ILK modulates epithelial polarity and matrix formation in hair follicles.

Science.gov (United States)

Rudkouskaya, Alena; Welch, Ian; Dagnino, Lina

2014-03-01

Hair follicle morphogenesis requires coordination of multiple signals and communication between its epithelial and mesenchymal constituents. Cell adhesion protein platforms, which include integrins and integrin-linked kinase (ILK), are critical for hair follicle formation. However, their precise contribution to this process is poorly understood. We show that in the absence of ILK, the hair follicle matrix lineage fails to develop, likely due to abnormalities in development of apical-basal cell polarity, as well as in laminin-511 and basement membrane assembly at the tip of the hair bud. These defects also result in impaired specification of hair matrix and absence of precortex and inner sheath root cell lineages. The molecular pathways affected in ILK-deficient follicles are similar to those in the absence of epidermal integrin β1 and include Wnt, but not sonic hedgehog, signaling. ILK-deficient hair buds also show abnormalities in the dermal papilla. Addition of exogenous laminin-511 restores morphological and molecular markers associated with hair matrix formation, indicating that ILK regulates hair bud cell polarity and functions upstream from laminin-511 assembly to regulate the developmental progression of hair follicles beyond the germ stage.

Fetal brain extracellular matrix boosts neuronal network formation in 3D bioengineered model of cortical brain tissue.

Science.gov (United States)

Sood, Disha; Chwalek, Karolina; Stuntz, Emily; Pouli, Dimitra; Du, Chuang; Tang-Schomer, Min; Georgakoudi, Irene; Black, Lauren D; Kaplan, David L

2016-01-01

The extracellular matrix (ECM) constituting up to 20% of the organ volume is a significant component of the brain due to its instructive role in the compartmentalization of functional microdomains in every brain structure. The composition, quantity and structure of ECM changes dramatically during the development of an organism greatly contributing to the remarkably sophisticated architecture and function of the brain. Since fetal brain is highly plastic, we hypothesize that the fetal brain ECM may contain cues promoting neural growth and differentiation, highly desired in regenerative medicine. Thus, we studied the effect of brain-derived fetal and adult ECM complemented with matricellular proteins on cortical neurons using in vitro 3D bioengineered model of cortical brain tissue. The tested parameters included neuronal network density, cell viability, calcium signaling and electrophysiology. Both, adult and fetal brain ECM as well as matricellular proteins significantly improved neural network formation as compared to single component, collagen I matrix. Additionally, the brain ECM improved cell viability and lowered glutamate release. The fetal brain ECM induced superior neural network formation, calcium signaling and spontaneous spiking activity over adult brain ECM. This study highlights the difference in the neuroinductive properties of fetal and adult brain ECM and suggests that delineating the basis for this divergence may have implications for regenerative medicine.

STRUCTURAL MODIFICATION OF NEW FORMATIONS IN CEMENT MATRIX USING CARBON NANOTUBE DISPERSIONS AND NANOSILICA

Directory of Open Access Journals (Sweden)

B. M. Khroustalev

2017-01-01

Full Text Available Complex nanodispersed systems with multi-walled carbon nanotubes and nanodispersed silica have a significant impact on the processes of hydration, hardening and strength gain of construction composites predetermining their durability. While using a scanning electron microscope with an attachment for X-ray microanalysis and a device for infrared spectral analysis investigations have shown that the main effect of the cement matrix modification in the case of adding complex nanodispersed systems is provided by direct influence of hydration processes with subsequent crystallization of new formations. It has been noted that while adding carbon nanotube dispersion and nanosized silica a binding matrix is structured in the form of an extremely dense shell from crystalline hydrate new formations on the surface of solid phases that provides strong binding matrix in cement concrete. The addition effect of carbon nanotubes has been analyzed and quantitatively assessed through an investigation for every case of one sample with nanotubes and one sample without them with the help of a nanoindenter and scanning electron microscope. It is necessary to solve rather complicated challenging task in order to assess quantitatively the addition effect of CNT on material characteristics at a micromechanical level. At the same time it is possible to investigate surface of a concrete sample with one-micron resolution. In this case it is necessary to prepare samples for nanoindentation with exclusion of all CNT defectable effects that have been shown by a SEM. So in this case more adequate method for assessment must be a picoindenter , which combines a test method for nanoindentation with an optical SEM potential. Such equipment is in the stage of in-situ testing process at the Vienna University of Technology. The investigation is based on the fact that the main modification effect of mineral binding matrix while using incorporated complex nanodispersed systems and

The role of formative feedback in promoting higher order thinking ...

African Journals Online (AJOL)

The role of formative feedback in promoting higher order thinking skills in ... activities, task characteristics, validating students' thinking, and providing feedback. ... Keywords: classroom environment, formative assessment, formative feedback, ...

Fibronectin alters the rate of formation and structure of the fibrin matrix.

Science.gov (United States)

Ramanathan, Anand; Karuri, Nancy

2014-01-10

Plasma fibronectin is a vital component of the fibrin clot; however its role on clot structure is not clearly understood. The goal of this study was to examine the influence of fibronectin on the kinetics of formation, structural characteristics and composition of reconstituted fibrin clots or fibrin matrices. Fibrin matrices were formed by adding thrombin to 1, 2 or 4 mg/ml fibrinogen supplemented with 0-0.4 mg/ml fibronectin. The rate of fibrin matrix formation was then monitored by measuring light absorbance properties at different time points. Confocal microscopy of fluorescein conjugated fibrinogen was used to visualize the structural characteristics of fibrin matrices. The amount of fibronectin in fibrin matrices was determined through electrophoresis and immunoblotting of solubilized matrices. Fibronectin concentration positively correlated with the initial rate of fibrin matrix formation and with steady state light absorbance values of fibrin matrices. An increase in fibronectin concentration resulted in thinner and denser fibers in the fibrin matrices. Electrophoresis and immunoblotting showed that fibronectin was covalently and non-covalently bound to fibrin matrices and in the form of high molecular weight multimers. The formation of fibronectin multimers was attributed to cross-linking of fibronectin by trace amounts Factor XIIIa. These findings are novel because they link results from light absorbance studies to microcopy analyses and demonstrate an influence of fibronectin on fibrin matrix structural characteristics. This data is important in developing therapies that destabilize fibrin clots. Copyright © 2014. Published by Elsevier Inc.

Dermatopontin interacts with fibronectin, promotes fibronectin fibril formation, and enhances cell adhesion.

Science.gov (United States)

Kato, Aiko; Okamoto, Osamu; Ishikawa, Kazushi; Sumiyoshi, Hideaki; Matsuo, Noritaka; Yoshioka, Hidekatsu; Nomizu, Motoyoshi; Shimada, Tatsuo; Fujiwara, Sakuhei

2011-04-29

We report that dermatopontin (DP), an abundant dermal extracellular matrix protein, is found in the fibrin clot and in the wound fluid, which comprise the provisional matrix at the initial stage of wound healing. DP was also found in the serum but at a lower concentration than that in wound fluid. DP co-localized with both fibrin and fibronectin on fibrin fibers and interacted with both proteins. Both normal fibroblast and HT1080 cell adhesion to the fibrin-fibronectin matrix were dose-dependently enhanced by DP, and the adhesion was mediated by α5β1 integrin. The cytoskeleton was more organized in the cells that adhered to the fibrin-fibronectin-DP complex. When incubated with DP, fibronectin formed an insoluble complex of fibronectin fibrils as visualized by electron microscopy. The interacting sites of fibronectin with DP were the first, thirteenth, and fourteenth type III repeats (III(1), III(13), and III(14)), with III(13) and III(14) assumed to be the major sites. The interaction between III(2-3) and III(12-14) was inhibited by DP, whereas the interaction between I(1-5) and III(12-14) was specifically and strongly enhanced by DP. Because the interaction between III(2-3) and III(12-14) is involved in forming a globular conformation of fibronectin, and that between I(1-5) and III(12-14) is required for forming fibronectin fibrils, DP promotes fibronectin fibril formation probably by changing the fibronectin conformation. These results suggest that DP has an accelerating role in fibroblast cell adhesion to the provisional matrix in the initial stage of wound healing.

An anti vimentin antibody promotes tube formation

DEFF Research Database (Denmark)

Jørgensen, Mathias Lindh; Møller, Carina Kjeldahl; Rasmussen, Lasse

2017-01-01

antibody technology, promotes tube formation of endothelial cells in a 2D matrigel assay. By binding vimentin, the antibody increases the tube formation by 21% after 5 hours of incubation. Addition of the antibody directly to cultured endothelial cells does not influence endothelial cell migration...... or proliferation. The enhanced tube formation can be seen for up to 10 hours where after the effect decreases. It is shown that the antibody-binding site is located on the coil 2 domain of vimentin. To our knowledge this is the first study that demonstrates an enhanced tube formation by binding vimentin in a 2D...

Extracellular DNA facilitates the formation of functional amyloids in Staphylococcus aureus biofilms.

Science.gov (United States)

Schwartz, Kelly; Ganesan, Mahesh; Payne, David E; Solomon, Michael J; Boles, Blaise R

2016-01-01

Persistent staphylococcal infections often involve surface-associated communities called biofilms. Staphylococcus aureus biofilm development is mediated by the co-ordinated production of the biofilm matrix, which can be composed of polysaccharides, extracellular DNA (eDNA) and proteins including amyloid fibers. The nature of the interactions between matrix components, and how these interactions contribute to the formation of matrix, remain unclear. Here we show that the presence of eDNA in S. aureus biofilms promotes the formation of amyloid fibers. Conditions or mutants that do not generate eDNA result in lack of amyloids during biofilm growth despite the amyloidogeneic subunits, phenol soluble modulin peptides, being produced. In vitro studies revealed that the presence of DNA promotes amyloid formation by PSM peptides. Thus, this work exposes a previously unacknowledged interaction between biofilm matrix components that furthers our understanding of functional amyloid formation and S. aureus biofilm biology. © 2015 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells.

Science.gov (United States)

Li, Q S; Meng, F Y; Zhao, Y H; Jin, C L; Tian, J; Yi, X J

2017-08-01

This study aimed to investigate the functional effects of microRNA (miR)-214-5p on osteoblastic cells, which might provide a potential role of miR-214-5p in bone fracture healing. Blood samples were obtained from patients with hand fracture or intra-articular calcaneal fracture and from healthy controls (HCs). Expression of miR-214-5p was monitored by qRT-PCR at day 7, 14 and 21 post-surgery. Mouse osteoblastic MC3T3-E1 cells were transfected with antisense oligonucleotides (ASO)-miR-214-5p, collagen type IV alpha 1 (COL4A1) vector or their controls; thereafter, cell viability, apoptotic rate, and the expression of collagen type I alpha 1 (COL1A1), type II collagen (COL-II), and type X collagen (COL-X) were determined. Luciferase reporter assay, qRT-PCR, and Western blot were performed to ascertain whether COL4A1 was a target of miR-214-5p. Plasma miR-214-5p was highly expressed in patients with bone fracture compared with HCs after fracture (p extracellular matrix (ECM) formation of osteoblastic MC3T3-E1 cells by targeting COL4A1. Cite this article: Q. S. Li, F. Y. Meng, Y. H. Zhao, C. L. Jin, J. Tian, X. J. Yi. Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells. Bone Joint Res 2017;6:464-471. DOI: 10.1302/2046-3758.68.BJR-2016-0208.R2. © 2017 Yi et al.

Matrix metalloproteinases regulate the formation of dendritic spine head protrusions during chemically induced long-term potentiation.

Directory of Open Access Journals (Sweden)

Zsuzsanna Szepesi

Full Text Available Dendritic spines are are small membranous protrusions that extend from neuronal dendrites and harbor the majority of excitatory synapses. Increasing evidence has shown that matrix metalloproteinases (MMPs, a family of extracellularly acting and Zn(2+-dependent endopeptidases, are able to rapidly modulate dendritic spine morphology. Spine head protrusions (SHPs are filopodia-like processes that extend from the dendritic spine head, representing a form of postsynaptic structural remodeling in response to altered neuronal activity. Herein, we show that chemically induced long-term potentiation (cLTP in dissociated hippocampal cultures upregulates MMP-9 activity that controls the formation of SHPs. Blocking of MMPs activity or microtubule dynamics abolishes the emergence of SHPs. In addition, autoactive recombinant MMP-9, promotes the formation of SHPs in organotypic hippocampal slices. Furthermore, spines with SHPs gained postsynaptic α-amino-3-hydroxyl-5-methyl-4-isoxazole propionic acid (AMPA receptors upon cLTP and the synaptic delivery of AMPA receptors was controlled by MMPs. The present results strongly imply that MMP-9 is functionally involved in the formation of SHPs and the control of postsynaptic receptor distribution upon cLTP.

Influence of short-term aluminum exposure on demineralized bone matrix induced bone formation

Energy Technology Data Exchange (ETDEWEB)

Severson, A.R. (Minnesota Univ., Duluth, MN (United States). Dept. of Anatomy and Cell Biology); Haut, C.F.; Firling, C.E. (Minnesota Univ., Duluth, MN (United States). Dept. of Biology); Huntley, T.E. (Minnesota Univ., Duluth, MN (United States). Dept. of Biochemistry and Molecular Biology)

1992-12-01

The effects of aluminum exposure on bone formation employing the demineralized bone matrix (DBM) induced bone development model were studied using 4-week-old Sprague-Dawley rats injected with a saline (control) or an aluminum chloride (experimental) solution. After 2 weeks of aluminum treatment, 20-mg portions of rat DBM were implanted subcutaneously on each side in the thoracic region of the control and experimental rats. Animals were killed 7, 12, or 21 days after implantation of the DBM and the developing plaques removed. No morphological, histochemical, or biochemical differences were apparent between plaques from day 7 control and experimental rats. Plaques from day 12 control and experimental rats exhibited cartilage formation and alkaline phosphatase activity localized in osteochondrogenic cells, chondrocytes, osteoblasts, and extracellular matrix. Unlike the plaques from control rats that contained many osteoblastic mineralizing fronts, the plaques from the 12-day experimental group had a preponderance of cartilaginous tissue, no evidence of mineralization, increased levels of alkaline phosphatase activity, and a reduced calcium content. Plaques developing for 21 days in control animals demonstrated extensive new bone formation and bone marrow development, while those in the experimental rats demonstrated unmineralized osteoid-like matrix with poorly developed bone marrow. Alkaline phosphatase activity of the plaques continued to remain high on day 21 for the control and experimental groups. Calcium levels were significantly reduced in the experimental group. These biochemical changes correlated with histochemical reductions in bone calcification. Thus, aluminum administration to rats appears to alter the differentiation and calcification of developing cartilage and bone in the DBM-induced bone formation model and suggests that aluminum by some mechanism alters the matrix calcification in growing bones. (orig.).

Sparse matrix-vector multiplication on GPGPU clusters: A new storage format and a scalable implementation

OpenAIRE

Kreutzer, Moritz; Hager, Georg; Wellein, Gerhard; Fehske, Holger; Basermann, Achim; Bishop, Alan R.

2011-01-01

Sparse matrix-vector multiplication (spMVM) is the dominant operation in many sparse solvers. We investigate performance properties of spMVM with matrices of various sparsity patterns on the nVidia “Fermi” class of GPGPUs. A new “padded jagged diagonals storage” (pJDS) format is proposed which may substantially reduce the memory overhead intrinsic to the widespread ELLPACK-R scheme while making no assumptions about the matrix structure. In our test scenarios the pJDS format cuts the ...

Osteoblast Differentiation and Bone Matrix Formation In Vivo and In Vitro.

Science.gov (United States)

Blair, Harry C; Larrouture, Quitterie C; Li, Yanan; Lin, Hang; Beer-Stoltz, Donna; Liu, Li; Tuan, Rocky S; Robinson, Lisa J; Schlesinger, Paul H; Nelson, Deborah J

2017-06-01

We review the characteristics of osteoblast differentiation and bone matrix synthesis. Bone in air breathing vertebrates is a specialized tissue that developmentally replaces simpler solid tissues, usually cartilage. Bone is a living organ bounded by a layer of osteoblasts that, because of transport and compartmentalization requirements, produce bone matrix exclusively as an organized tight epithelium. With matrix growth, osteoblasts are reorganized and incorporated into the matrix as living cells, osteocytes, which communicate with each other and surface epithelium by cell processes within canaliculi in the matrix. The osteoblasts secrete the organic matrix, which are dense collagen layers that alternate parallel and orthogonal to the axis of stress loading. Into this matrix is deposited extremely dense hydroxyapatite-based mineral driven by both active and passive transport and pH control. As the matrix matures, hydroxyapatite microcrystals are organized into a sophisticated composite in the collagen layer by nucleation in the protein lattice. Recent studies on differentiating osteoblast precursors revealed a sophisticated proton export network driving mineralization, a gene expression program organized with the compartmentalization of the osteoblast epithelium that produces the mature bone matrix composite, despite varying serum calcium and phosphate. Key issues not well defined include how new osteoblasts are incorporated in the epithelial layer, replacing those incorporated in the accumulating matrix. Development of bone in vitro is the subject of numerous projects using various matrices and mesenchymal stem cell-derived preparations in bioreactors. These preparations reflect the structure of bone to variable extents, and include cells at many different stages of differentiation. Major challenges are production of bone matrix approaching the in vivo density and support for trabecular bone formation. In vitro differentiation is limited by the organization and

Fibroblast Cluster Formation on 3D Collagen Matrices Requires Cell Contraction-Dependent Fibronectin Matrix Organization

Science.gov (United States)

da Rocha-Azevedo, Bruno; Ho, Chin-Han; Grinnell, Frederick

2012-01-01

Fibroblasts incubated on 3D collagen matrices in serum or lysophosphatidic acid (LPA)-containing medium self-organize into clusters through a mechanism that requires cell contraction. However, in platelet-derived growth factor (PDGF)-containing medium, cells migrate as individuals and do not form clusters even though they constantly encounter each other. Here, we present evidence that a required function of cell contraction in clustering is formation of fibronectin fibrillar matrix. We found that in serum or LPA but not in PDGF or basal medium, cells organized FN (both serum and cellular) into a fibrillar, detergent-insoluble matrix. Cell clusters developed concomitant with FN matrix formation. FN fibrils accumulated beneath cells and along the borders of cell clusters in regions of cell-matrix tension. Blocking Rho kinase or myosin II activity prevented FN matrix assembly and cell clustering. Using siRNA silencing and function-blocking antibodies and peptides, we found that cell clustering and FN matrix assembly required α5β1 integrins and fibronectin. Cells were still able to exert contractile force and compact the collagen matrix under the latter conditions, which showed that contraction was not sufficient for cell clustering to occur. Our findings provide new insights into how procontractile (serum/LPA) and promigratory (PDGF) growth factor environments can differentially regulate FN matrix assembly by fibroblasts interacting with collagen matrices and thereby influence mesenchymal cell morphogenetic behavior under physiologic circumstances such as wound repair, morphogenesis and malignancy. PMID:23117111

Fibroblast cluster formation on 3D collagen matrices requires cell contraction dependent fibronectin matrix organization.

Science.gov (United States)

da Rocha-Azevedo, Bruno; Ho, Chin-Han; Grinnell, Frederick

2013-02-15

Fibroblasts incubated on 3D collagen matrices in serum or lysophosphatidic acid (LPA)-containing medium self-organize into clusters through a mechanism that requires cell contraction. However, in platelet-derived growth factor (PDGF)-containing medium, cells migrate as individuals and do not form clusters even though they constantly encounter each other. Here, we present evidence that a required function of cell contraction in clustering is formation of fibronectin (FN) fibrillar matrix. We found that in serum or LPA but not in PDGF or basal medium, cells organized FN (both serum and cellular) into a fibrillar, detergent-insoluble matrix. Cell clusters developed concomitant with FN matrix formation. FN fibrils accumulated beneath cells and along the borders of cell clusters in regions of cell-matrix tension. Blocking Rho kinase or myosin II activity prevented FN matrix assembly and cell clustering. Using siRNA silencing and function-blocking antibodies and peptides, we found that cell clustering and FN matrix assembly required α5β1 integrins and fibronectin. Cells were still able to exert contractile force and compact the collagen matrix under the latter conditions, which showed that contraction was not sufficient for cell clustering to occur. Our findings provide new insights into how procontractile (serum/LPA) and promigratory (PDGF) growth factor environments can differentially regulate FN matrix assembly by fibroblasts interacting with collagen matrices and thereby influence mesenchymal cell morphogenetic behavior under physiologic circumstances such as wound repair, morphogenesis and malignancy. Copyright © 2012 Elsevier Inc. All rights reserved.

Protein kinase C involvement in focal adhesion formation

DEFF Research Database (Denmark)

Woods, A; Couchman, J R

1992-01-01

Matrix molecules such as fibronectin can promote cell attachment, spreading and focal adhesion formation. Although some interactions of fibronectin with cell surface receptors have now been identified, the consequent activation of intracellular messenger systems by cell/matrix interactions have...... still to be elucidated. We show here that the kinase inhibitors H7 and HA1004 reduce focal adhesion and stress fiber formation in response to fibronectin in a dose-dependent manner, and that activators of protein kinase C can promote their formation under conditions where they do not normally form....... Fibroblasts spread within 1h on substrata composed of fibronectin and formed focal adhesions by 3h, as monitored by interference reflection microscopy (IRM) and by labeling for talin, vinculin and integrin beta 1 subunits. In addition, stress fibers were visible. When cells were allowed to spread for 1h...

NDMA formation from amine-based pharmaceuticals--impact from prechlorination and water matrix.

Science.gov (United States)

Shen, Ruqiao; Andrews, Susan A

2013-05-01

The presence of N-nitrosodimethylamine (NDMA) in drinking water is most commonly associated with the chloramination of amine-based precursors. One option to control the NDMA formation is to remove the precursors via pre-oxidation, and prechlorination is among the most effective options in reducing NDMA formation. However, most of the findings to-date are based on single-precursor scenarios using the model precursor dimethylamine (DMA) and natural organic matter (NOM), while few studies have considered the potential interactions between water matrix components and the target precursors when investigating the prechlorination impact. Specifically, little is known for the behaviour of amine-based pharmaceuticals which have recently been reported to contribute to NDMA formation upon chloramination. This work demonstrates that prechlorination can affect both the ultimate NDMA conversion and the reaction kinetics from selected pharmaceuticals, and the nature and extent of the impact was compound-specific and matrix-specific. In the absence of NOM, the NDMA formation from most pharmaceuticals was reduced upon prechlorination, except for sumatriptan which showed a consistent increase in NDMA formation with increasing free chlorine contact time. In the presence of NOM, prechlorination was shown to enhance initial reactions by reducing the binding between NOM and pharmaceuticals, but prolonged prechlorination broke down NOM into smaller products which could then form new bonds with pharmaceuticals and thus inhibit their further conversion into NDMA. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanisms of formation damage in matrix-permeability geothermal wells

Energy Technology Data Exchange (ETDEWEB)

Bergosh, J.L.; Wiggins, R.B.; Enniss, D.O.

1982-04-01

Tests were conducted to determine mechanisms of formation damage that can occur in matrix permeability geothermal wells. Two types of cores were used in the testing, actual cores from the East Mesa Well 78-30RD and cores from a fairly uniform generic sandstone formation. Three different types of tests were run. The East Mesa cores were used in the testing of the sensitivity of core to filtrate chemistry. The tests began with the cores exposed to simulated East Mesa brine and then different filtrates were introduced and the effects of the fluid contrast on core permeability were measured. The East Mesa cores were also used in the second series of tests which tested formation sandstone cores were used in the third test series which investigated the effects of different sizes of entrained particles in the fluid. Tests were run with both single-particle sizes and distributions of particle mixes. In addition to the testing, core preparation techniques for simulating fracture permeability were evaluated. Three different fracture formation mechanisms were identified and compared. Measurement techniques for measuring fracture size and permeability were also developed.

A Comparative Study of Collagen Matrix Density Effect on Endothelial Sprout Formation Using Experimental and Computational Approaches.

Science.gov (United States)

Shamloo, Amir; Mohammadaliha, Negar; Heilshorn, Sarah C; Bauer, Amy L

2016-04-01

A thorough understanding of determining factors in angiogenesis is a necessary step to control the development of new blood vessels. Extracellular matrix density is known to have a significant influence on cellular behaviors and consequently can regulate vessel formation. The utilization of experimental platforms in combination with numerical models can be a powerful method to explore the mechanisms of new capillary sprout formation. In this study, using an integrative method, the interplay between the matrix density and angiogenesis was investigated. Owing the fact that the extracellular matrix density is a global parameter that can affect other parameters such as pore size, stiffness, cell-matrix adhesion and cross-linking, deeper understanding of the most important biomechanical or biochemical properties of the ECM causing changes in sprout morphogenesis is crucial. Here, we implemented both computational and experimental methods to analyze the mechanisms responsible for the influence of ECM density on the sprout formation that is difficult to be investigated comprehensively using each of these single methods. For this purpose, we first utilized an innovative approach to quantify the correspondence of the simulated collagen fibril density to the collagen density in the experimental part. Comparing the results of the experimental study and computational model led to some considerable achievements. First, we verified the results of the computational model using the experimental results. Then, we reported parameters such as the ratio of proliferating cells to migrating cells that was difficult to obtain from experimental study. Finally, this integrative system led to gain an understanding of the possible mechanisms responsible for the effect of ECM density on angiogenesis. The results showed that stable and long sprouts were observed at an intermediate collagen matrix density of 1.2 and 1.9 mg/ml due to a balance between the number of migrating and proliferating

Effects of interface formation kinetics on the microstructural properties of wear-resistant metal-matrix composites

International Nuclear Information System (INIS)

Ilo, S.; Just, Ch.; Badisch, E.; Wosik, J.; Danninger, H.

2010-01-01

Research highlights: The dissolution reaction kinetics and the formation of intermediate layers of tungsten carbides in Ni-(Cr)-B-Si matrices were studied in liquid-phase sintering with well-defined temperature/time relationship. → The internal intermediate layer formation, close to the original primary tungsten carbide showed diffusion-controlled kinetic (∼t 0.5 ), whereas the outside layer thickness formation, proportional to the processing time (∼t), was formed by the subsequent eutectic reaction of the Ni-(Cr)-B-Si matrix with the WC/W 2 C component. → Cr-addition in the matrix highly influences the inner layer thickness caused probably by increasing the C-diffusion rate, whereas the outer layer thickness was not dependent on the initial Cr-content in the matrix. Generally, the Cr-addition in the Ni-based matrix increased the hardness and elastic modulus of the intermediate phases along the carbide/matrix interface. → The different microstructure gradients are depended mainly on the interface growth kinetics. → The intermediate layers are hard phases (carbides, borides or carbo-borides). → The hardness of the carbide/matrix interface area is significantly lower as the hardness of the original primary tungsten carbides. - Abstract: Hard-particle metal-matrix composites (MMC) are generally used to increase the lifetime of machinery equipment exposed to severe wear conditions. Depending on the manufacturing technology, dissolution reactions of hard phases undergo different temperature/time profiles during processing affecting the microstructure and mechanical properties of the MMCs. Therefore, quantification of the carbide dissolution effects on the microstructure and micro-mechanical properties is the key to success in the development and optimisation of MMCs. Dissolution kinetics of WC/W 2 C in Ni-based matrices were determined in the liquid-sintering with a well-defined temperature/time profile. Microscopic evaluation of the samples showed two

Thromboxane A(2 receptor stimulation promotes closure of the rat ductus arteriosus through enhancing neointima formation.

Directory of Open Access Journals (Sweden)

Tomohiro Yokota

Full Text Available Ductus arteriosus (DA closure follows constriction and remodeling of the entire vessel wall. Patent ductus arteriosus occurs when the DA does not close after birth, and this condition is currently treated using cyclooxygenase inhibitors. However, the efficacy of cyclooxygenase inhibitors is often limited. Our previous study demonstrated that low-dose thromboxane A2 receptor (TP stimulation constricted the DA with minimal adverse effects in rat neonates. However, its effect on DA remodeling remains unknown. In this study, we focused on the impact of the exogenous TP stimulation on the DA remodeling, especially intimal thickening. Using DA explants from rat fetuses at embryonic day 19 as a ex vivo model and primary cultured rat DA smooth muscle cells from embryonic day 21 as a in vitro model, we evaluated the effect of TP stimulation on the DA remodeling. The selective TP agonists U46619 and I-BOP promoted neointima formation in the ex vivo DA explants, and TP stimulation increased DA SMC migration in a dose-dependent manner. Both effects were inhibited by the selective TP antagonist SQ29548 or the siRNA against TP. TP stimulation also increased DA SMC proliferation in the presence of 10% fetal bovine serum. LC/MS/MS analysis revealed that TP stimulation increased secretion of several extracellular matrix proteins that may contribute to an increase in neointima formation. In conclusion, we uncovered that exogenous administration of TP agonist promotes neointima formation through the induction of migration and proliferation of DA SMC, which could contribute to DA closure and also to its vasoconstrictive action.

Extracellular matrix dynamics during vertebrate axis formation.

Science.gov (United States)

Czirók, András; Rongish, Brenda J; Little, Charles D

2004-04-01

The first evidence for the dynamics of in vivo extracellular matrix (ECM) pattern formation during embryogenesis is presented below. Fibrillin 2 filaments were tracked for 12 h throughout the avian intraembryonic mesoderm using automated light microscopy and algorithms of our design. The data show that these ECM filaments have a reproducible morphogenic destiny that is characterized by directed transport. Fibrillin 2 particles initially deposited in the segmental plate mesoderm are translocated along an unexpected trajectory where they eventually polymerize into an intricate scaffold of cables parallel to the anterior-posterior axis. The cables coalesce near the midline before the appearance of the next-formed somite. Moreover, the ECM filaments define global tissue movements with high precision because the filaments act as passive motion tracers. Quantification of individual and collective filament "behaviors" establish fate maps, trajectories, and velocities. These data reveal a caudally propagating traveling wave pattern in the morphogenetic movements of early axis formation. We conjecture that within vertebrate embryos, long-range mechanical tension fields are coupled to both large-scale patterning and local organization of the ECM. Thus, physical forces or stress fields are essential requirements for executing an emergent developmental pattern-in this case, paraxial fibrillin cable assembly.

Phase separation and formation of omega phase in the beta matrix of a Ti-V-Cu alloy

Energy Technology Data Exchange (ETDEWEB)

Ng, H.P. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Devaraj, A.; Nag, S. [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Bettles, C.J. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Gibson, M. [CSIRO Process Science and Engineering, Locked Bag 10, Clayton South, Victoria 3169 (Australia); Fraser, H.L. [Center for the Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH (United States); Muddle, B.C. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Banerjee, R., E-mail: rajarshi.banerjee@unt.edu [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States)

2011-05-15

The formation of the {omega} phase in the presence of simultaneous development of compositional modulations (or phase separation) within the body-centered cubic {beta} matrix phase of a Ti-10V-6Cu (wt.%) alloy during continuous cooling has been investigated using a combination of transmission electron microscopy and atom probe tomography. While a water quench from the high-temperature {beta} phase field allows apparently athermal formation of {omega} domains without any significant partitioning of solute or modulation in matrix composition, subsequent annealing at 500 {sup o}C for just 60 s leads to unusually rapid growth of the {omega} domains concurrent with, but apparently independent of, a slower development of finer-scale modulations in solute composition occurring apparently uniformly across both {omega} and {beta} phases. In contrast, on slower air cooling from the solution treatment temperature, there are pronounced compositional fluctuations within the {beta} phase, presumably as a product of spinodal decomposition, that are detectable prior to the formation of {omega} phase. The {omega} phase subsequently forms preferentially in solute-depleted regions of the matrix {beta}, with a composition reflecting the local matrix composition and a solute content significantly lower than the average matrix composition. As a result, it has a cuboidal morphology, distinguishably different from the elliposoidal form that is observed in samples water-quenched and annealed at 500 deg. C.

Function of Matrix IGF-1 in Coupling Bone Resorption and Formation

Science.gov (United States)

Crane, Janet L.; Cao, Xu

2013-01-01

Balancing bone resorption and formation is the quintessential component for the prevention of osteoporosis. Signals that determine the recruitment, replication, differentiation, function, and apoptosis of osteoblasts and osteoclasts direct bone remodeling and determine whether bone tissue is gained, lost, or balanced. Therefore understanding the signaling pathways involved in the coupling process will help develop further targets for osteoporosis therapy, by blocking bone resorption or enhancing bone formation in a space and time dependent manner. Insulin-like growth factor type 1 (IGF-1) has long been known to play a role in bone strength. It is one of the most abundant substances in the bone matrix, circulates systemically and is secreted locally, and has a direct relationship with bone mineral density. Recent data has helped further our understanding of the direct role of IGF-1 signaling in coupling bone remodeling which will be discussed in this review. The bone marrow microenvironment plays a critical role in the fate of MSCs and HSCs and thus how IGF-1 interacts with other factors in the microenvironment are equally important. While previous clinical trials with IGF-1 administration have been unsuccessful at enhancing bone formation, advances in basic science studies have provided insight into further mechanisms that should be considered for future trials. Additional basic science studies dissecting the regulation and the function of matrix IGF-1 in modeling and remodeling will continue to provide further insight for future directions for anabolic therapies for osteoporosis. PMID:24068256

Function of matrix IGF-1 in coupling bone resorption and formation.

Science.gov (United States)

Crane, Janet L; Cao, Xu

2014-02-01

Balancing bone resorption and formation is the quintessential component for the prevention of osteoporosis. Signals that determine the recruitment, replication, differentiation, function, and apoptosis of osteoblasts and osteoclasts direct bone remodeling and determine whether bone tissue is gained, lost, or balanced. Therefore, understanding the signaling pathways involved in the coupling process will help develop further targets for osteoporosis therapy, by blocking bone resorption or enhancing bone formation in a space- and time-dependent manner. Insulin-like growth factor type 1 (IGF-1) has long been known to play a role in bone strength. It is one of the most abundant substances in the bone matrix, circulates systemically and is secreted locally, and has a direct relationship with bone mineral density. Recent data has helped further our understanding of the direct role of IGF-1 signaling in coupling bone remodeling which will be discussed in this review. The bone marrow microenvironment plays a critical role in the fate of mesenchymal stem cells and hematopoietic stem cells and thus how IGF-1 interacts with other factors in the microenvironment are equally important. While previous clinical trials with IGF-1 administration have been unsuccessful at enhancing bone formation, advances in basic science studies have provided insight into further mechanisms that should be considered for future trials. Additional basic science studies dissecting the regulation and the function of matrix IGF-1 in modeling and remodeling will continue to provide further insight for future directions for anabolic therapies for osteoporosis.

In vitro human periodontal ligament-like tissue formation with porous poly-L-lactide matrix

International Nuclear Information System (INIS)

Liao, Wen; Okada, Masahiro; Sakamoto, Fumito; Okita, Naoya; Inami, Kaoru; Nishiura, Aki; Hashimoto, Yoshiya; Matsumoto, Naoyuki

2013-01-01

This study aimed to establish an in vitro human periodontal ligament-like tissue (HPdLLT) by three-dimensional culturing of human periodontal ligament fibroblasts (HPdLFs) in a porous poly-L-lactide (PLLA) matrix modified hydrophilically with ammonia solution. After ammonia modification, the surface roughness and culture-medium-soaking-up ability of the PLLA matrix increased, whereas the contact angle of water drops decreased. The thickness, porosity, and pore size of the PLLA matrix were 400 ± 50 μm, 83.3%, and 75–150 μm, respectively. HPdLFs (1 × 10 5 cells) were seeded on the modified PLLA matrix and centrifuged to facilitate seeding into its interior and cultured for 14 days. Scanning electron microscope (SEM) observation, proliferation assay, picrosirius-red staining, and real-time polymerase chain reaction (RT-PCR) for type-1 collagen (COL1), periodontal ligament associated protein-1 (PLAP-1), fibroblast growth factor-2 (FGF-2), and alkaline phosphatase (ALP) mRNA were conducted on days 1, 3, 7, and 14. HPdLFs were observed entirely from the surface to the rear side of the matrix. Cell proliferation analysis, SEM observation, and picrosirius-red staining showed both progressive growth of 3D-cultured HPdLFs and extracellular matrix maturation by the secretion of COL1 and type 3 collagen (COL3) from days 1 to 14. Expressions of COL1, PLAP-1, and FGF-2 mRNA suggested the formation of cellular components and supplementation of extracellular components. Expressions of ALP, COL1, and PLAP-1 mRNA suggested the osteogenic potential of the HPdLLT. The results indicated in vitro HPdLLT formation, and it could be used in future periodontal ligament tissue engineering to achieve optimal periodontal regeneration. - Highlights: • First report on ammonia treated PLLA matrix for in vitro human periodontal ligament-like tissue generation. • Good combination of matrix thickness, pore size, and porosity. • Biodegradable PLLA is also possible to be used in vivo

In vitro human periodontal ligament-like tissue formation with porous poly-L-lactide matrix

Energy Technology Data Exchange (ETDEWEB)

Liao, Wen [Graduate School of Dentistry, Department of Orthodontics, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan); Okada, Masahiro [Department of Biomaterials, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan); Sakamoto, Fumito; Okita, Naoya [Graduate School of Dentistry, Department of Orthodontics, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan); Inami, Kaoru; Nishiura, Aki [Department of Orthodontics, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan); Hashimoto, Yoshiya, E-mail: yoshiya@cc.osaka-dent.ac.jp [Department of Biomaterials, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan); Matsumoto, Naoyuki [Department of Orthodontics, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata-shi, Osaka-fu 573-1121 (Japan)

2013-08-01

This study aimed to establish an in vitro human periodontal ligament-like tissue (HPdLLT) by three-dimensional culturing of human periodontal ligament fibroblasts (HPdLFs) in a porous poly-L-lactide (PLLA) matrix modified hydrophilically with ammonia solution. After ammonia modification, the surface roughness and culture-medium-soaking-up ability of the PLLA matrix increased, whereas the contact angle of water drops decreased. The thickness, porosity, and pore size of the PLLA matrix were 400 ± 50 μm, 83.3%, and 75–150 μm, respectively. HPdLFs (1 × 10{sup 5} cells) were seeded on the modified PLLA matrix and centrifuged to facilitate seeding into its interior and cultured for 14 days. Scanning electron microscope (SEM) observation, proliferation assay, picrosirius-red staining, and real-time polymerase chain reaction (RT-PCR) for type-1 collagen (COL1), periodontal ligament associated protein-1 (PLAP-1), fibroblast growth factor-2 (FGF-2), and alkaline phosphatase (ALP) mRNA were conducted on days 1, 3, 7, and 14. HPdLFs were observed entirely from the surface to the rear side of the matrix. Cell proliferation analysis, SEM observation, and picrosirius-red staining showed both progressive growth of 3D-cultured HPdLFs and extracellular matrix maturation by the secretion of COL1 and type 3 collagen (COL3) from days 1 to 14. Expressions of COL1, PLAP-1, and FGF-2 mRNA suggested the formation of cellular components and supplementation of extracellular components. Expressions of ALP, COL1, and PLAP-1 mRNA suggested the osteogenic potential of the HPdLLT. The results indicated in vitro HPdLLT formation, and it could be used in future periodontal ligament tissue engineering to achieve optimal periodontal regeneration. - Highlights: • First report on ammonia treated PLLA matrix for in vitro human periodontal ligament-like tissue generation. • Good combination of matrix thickness, pore size, and porosity. • Biodegradable PLLA is also possible to be used in vivo.

High-Frequency Promoter Firing Links THO Complex Function to Heavy Chromatin Formation

DEFF Research Database (Denmark)

Mouaikel, John; Causse, Sébastien Z; Rougemaille, Mathieu

2013-01-01

The THO complex is involved in transcription, genome stability, and messenger ribonucleoprotein (mRNP) formation, but its precise molecular function remains enigmatic. Under heat shock conditions, THO mutants accumulate large protein-DNA complexes that alter the chromatin density of target genes...... (heavy chromatin), defining a specific biochemical facet of THO function and a powerful tool of analysis. Here, we show that heavy chromatin distribution is dictated by gene boundaries and that the gene promoter is necessary and sufficient to convey THO sensitivity in these conditions. Single......-molecule fluorescence insitu hybridization measurements show that heavy chromatin formation correlates with an unusually high firing pace of the promoter with more than 20 transcription events per minute. Heavy chromatin formation closely follows the modulation of promoter firing and strongly correlates with polymerase...

Chinese red yeast rice (Monascus purpureus-fermented rice promotes bone formation

Directory of Open Access Journals (Sweden)

Rabie Bakr

2008-03-01

Full Text Available Abstract Background Statin can induce the gene expression of bone morphogenetic protein-2. Red yeast rice (RYR, Hongqu, i.e. rice fermented with Monascus purpureus, contains a natural form of statin. This study demonstrates the effects of RYR extract on bone formation. Methods Bone defects were created in the parietal bones of two New Zealand white rabbits. In the test animal, two defects were grafted with collagen matrix mixed with RYR extract. In the control animal, two defects were grafted with collagen matrix alone. UMR 106 cell line was used to test RYR extract in vitro. In the control group, cells were cultured for three durations (24 hours, 48 hours and 72 hours without any intervention. In the RYR group, cells were cultured for the same durations with various concentrations of RYR extract (0.001 g/ml, 0.005 g/ml and 0.01 g/ml. Bicinchoninic acid (BCA assay, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and alkaline phosphatase (ALP assay were performed to measure total protein, mitochondrial activity and bone cell formation respectively. Results The test animal showed more formation of new bone in the defects than the control animal. RYR significantly increased the optical density in the MTT assay and ALP activity in vitro. Conclusion RYR extract stimulated new bone formation in bone defects in vivo and increased bone cell formation in vitro.

Polymer nanocomposites enhance S-nitrosoglutathione intestinal absorption and promote the formation of releasable nitric oxide stores in rat aorta.

Science.gov (United States)

Wu, Wen; Perrin-Sarrado, Caroline; Ming, Hui; Lartaud, Isabelle; Maincent, Philippe; Hu, Xian-Ming; Sapin-Minet, Anne; Gaucher, Caroline

2016-10-01

Alginate/chitosan nanocomposite particles (GSNO-acNCPs), i.e. S-nitrosoglutathione (GSNO) loaded polymeric nanoparticles incorporated into an alginate and chitosan matrix, were developed to increase the effective GSNO loading capacity, a nitric oxide (NO) donor, and to sustain its release from the intestine following oral administration. Compared with free GSNO and GSNO loaded nanoparticles, GSNO-acNCPs promoted 2.7-fold GSNO permeation through a model of intestinal barrier (Caco-2 cells). After oral administration to Wistar rats, GSNO-acNCPs promoted NO storage into the aorta during at least 17h, as highlighted by (i) a long-lasting hyporeactivity to phenylephrine (decrease in maximum vasoconstrictive effect of aortic rings) and (ii) N-acetylcysteine (a thiol which can displace NO from tissues)-induced vasodilation of aorxxtic rings preconstricted with phenylephrine. In conclusion, GSNO-acNCPs enhance GSNO intestinal absorption and promote the formation of releasable NO stores into the rat aorta. GSNO-acNCPs are promising carriers for chronic oral application devoted to the treatment of cardiovascular diseases. Copyright © 2016. Published by Elsevier Inc.

Endothelial cell-derived matrix promotes the metabolic functional maturation of hepatocyte via integrin-Src signalling.

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Guo, Xinyue; Li, Weihong; Ma, Minghui; Lu, Xin; Zhang, Haiyan

2017-11-01

The extracellular matrix (ECM) microenvironment is involved in the regulation of hepatocyte phenotype and function. Recently, the cell-derived extracellular matrix has been proposed to represent the bioactive and biocompatible materials of the native ECM. Here, we show that the endothelial cell-derived matrix (EC matrix) promotes the metabolic maturation of human adipose stem cell-derived hepatocyte-like cells (hASC-HLCs) through the activation of the transcription factor forkhead box protein A2 (FOXA2) and the nuclear receptors hepatocyte nuclear factor 4 alpha (HNF4α) and pregnane X receptor (PXR). Reducing the fibronectin content in the EC matrix or silencing the expression of α5 integrin in the hASC-HLCs inhibited the effect of the EC matrix on Src phosphorylation and hepatocyte maturation. The inhibition of Src phosphorylation using the inhibitor PP2 or silencing the expression of Src in hASC-HLCs also attenuated the up-regulation of the metabolic function of hASC-HLCs in a nuclear receptor-dependent manner. These data elucidate integrin-Src signalling linking the extrinsic EC matrix signals and metabolic functional maturation of hepatocyte. This study provides a model for studying the interaction between hepatocytes and non-parenchymal cell-derived matrix. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Local effect of zoledronic acid on new bone formation in posterolateral spinal fusion with demineralized bone matrix in a murine model.

Science.gov (United States)

Zwolak, Pawel; Farei-Campagna, Jan; Jentzsch, Thorsten; von Rechenberg, Brigitte; Werner, Clément M

2018-01-01

Posterolateral spinal fusion is a common orthopaedic surgery performed to treat degenerative and traumatic deformities of the spinal column. In posteriolateral spinal fusion, different osteoinductive demineralized bone matrix products have been previously investigated. We evaluated the effect of locally applied zoledronic acid in combination with commercially available demineralized bone matrix putty on new bone formation in posterolateral spinal fusion in a murine in vivo model. A posterolateral sacral spine fusion in murine model was used to evaluate the new bone formation. We used the sacral spine fusion model to model the clinical situation in which a bone graft or demineralized bone matrix is applied after dorsal instrumentation of the spine. In our study, group 1 received decortications only (n = 10), group 2 received decortication, and absorbable collagen sponge carrier, group 3 received decortication and absorbable collagen sponge carrier with zoledronic acid in dose 10 µg, group 4 received demineralized bone matrix putty (DBM putty) plus decortication (n = 10), and group 5 received DBM putty, decortication and locally applied zoledronic acid in dose 10 µg. Imaging was performed using MicroCT for new bone formation assessment. Also, murine spines were harvested for histopathological analysis 10 weeks after surgery. The surgery performed through midline posterior approach was reproducible. In group with decortication alone there was no new bone formation. Application of demineralized bone matrix putty alone produced new bone formation which bridged the S1-S4 laminae. Local application of zoledronic acid to demineralized bone matrix putty resulted in significant increase of new bone formation as compared to demineralized bone matrix putty group alone. A single local application of zoledronic acid with DBM putty during posterolateral fusion in sacral murine spine model increased significantly new bone formation in situ in our model. Therefore, our

Tissue Inhibitor of Matrix Metalloproteinase-1 Promotes Myocardial Fibrosis by Mediating CD63-Integrin β1 Interaction.

Science.gov (United States)

Takawale, Abhijit; Zhang, Pu; Patel, Vaibhav B; Wang, Xiuhua; Oudit, Gavin; Kassiri, Zamaneh

2017-06-01

Myocardial fibrosis is excess accumulation of the extracellular matrix fibrillar collagens. Fibrosis is a key feature of various cardiomyopathies and compromises cardiac systolic and diastolic performance. TIMP1 (tissue inhibitor of metalloproteinase-1) is consistently upregulated in myocardial fibrosis and is used as a marker of fibrosis. However, it remains to be determined whether TIMP1 promotes tissue fibrosis by inhibiting extracellular matrix degradation by matrix metalloproteinases or via an matrix metalloproteinase-independent pathway. We examined the function of TIMP1 in myocardial fibrosis using Timp1 -deficient mice and 2 in vivo models of myocardial fibrosis (angiotensin II infusion and cardiac pressure overload), in vitro analysis of adult cardiac fibroblasts, and fibrotic myocardium from patients with dilated cardiomyopathy (DCM). Timp1 deficiency significantly reduced myocardial fibrosis in both in vivo models of cardiomyopathy. We identified a novel mechanism for TIMP1 action whereby, independent from its matrix metalloproteinase-inhibitory function, it mediates an association between CD63 (cell surface receptor for TIMP1) and integrin β1 on cardiac fibroblasts, initiates activation and nuclear translocation of Smad2/3 and β-catenin, leading to de novo collagen synthesis. This mechanism was consistently observed in vivo, in cultured cardiac fibroblasts, and in human fibrotic myocardium. In addition, after long-term pressure overload, Timp1 deficiency persistently reduced myocardial fibrosis and ameliorated diastolic dysfunction. This study defines a novel matrix metalloproteinase-independent function of TIMP1 in promoting myocardial fibrosis. As such targeting TIMP1 could prove to be a valuable approach in developing antifibrosis therapies. © 2017 American Heart Association, Inc.

Modulation of enamel matrix proteins on the formation and nano-assembly of hydroxyapatite in vitro

Energy Technology Data Exchange (ETDEWEB)

Li Hong, E-mail: tlihong@jnu.edu.cn [Department of Materials Science and Engineering, Jinan University, Guangzhou, Guangdong 510630 (China); Department of Bioengineering, Clemson University, Charleston, SC 29425 (United States); Huang Weiya [Department of Chemistry, Jinan University, Guangzhou, Guangdong 510630 (China); Department of Materials Science and Engineering, Taizhou, Taizhou University, Zhejiang 317000 (China); Zhang Yuanming [Department of Chemistry, Jinan University, Guangzhou, Guangdong 510630 (China); Xue Bo [Department of Materials Science and Engineering, Jinan University, Guangzhou, Guangdong 510630 (China); Wen Xuejun [Department of Bioengineering, Clemson University, Charleston, SC 29425 (United States)

2012-05-01

Natural enamel has a hierarchically nanoassembled architecture that is regulated by enamel matrix proteins (EMPs) during the formation of enamel crystals. To understand the role of EMPs on enamel mineralization, calcium phosphate (CaP) growth experiments in both the presence and absence of native rat EMPs in a single diffusion system were conducted. The morphology and organization of formed CaP crystals were examined by X-Ray Diffraction (XRD), High-Resolution Transmission Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED). In the system containing the EMPs, hydroxyapatite (HAP) with hierarchical lamellar nanostructure can be formed and the aligned HAP assembly tightly bundled by 3-4 rod-like nanocrystals like an enamel prism. However, in the absence of EMPs, only a sheet-like structure of octacalcium phosphate (OCP) phase was presented. EMPs promote HAP formation and inhibit the growth of OCP on the (010) plane. It is discussed that the organized Amelogenin/Amorphous Calcium Phosphate might be the precursor to the bundled HAP crystal prism. The study benefits the understanding of biomineralization of tooth enamel. - Highlights: Black-Right-Pointing-Pointer An aligned hydroxyapatite crystal bundled by rod-like nanosize crystals was obtained. Black-Right-Pointing-Pointer An organized Amel/ACP would be the precursor of the bundled hydroxyapatite crystal prism. Black-Right-Pointing-Pointer EMPs inhibit the growth of octacalcium phosphate in a defined plane.

Modulation of enamel matrix proteins on the formation and nano-assembly of hydroxyapatite in vitro

International Nuclear Information System (INIS)

Li Hong; Huang Weiya; Zhang Yuanming; Xue Bo; Wen Xuejun

2012-01-01

Natural enamel has a hierarchically nanoassembled architecture that is regulated by enamel matrix proteins (EMPs) during the formation of enamel crystals. To understand the role of EMPs on enamel mineralization, calcium phosphate (CaP) growth experiments in both the presence and absence of native rat EMPs in a single diffusion system were conducted. The morphology and organization of formed CaP crystals were examined by X-Ray Diffraction (XRD), High-Resolution Transmission Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED). In the system containing the EMPs, hydroxyapatite (HAP) with hierarchical lamellar nanostructure can be formed and the aligned HAP assembly tightly bundled by 3–4 rod-like nanocrystals like an enamel prism. However, in the absence of EMPs, only a sheet-like structure of octacalcium phosphate (OCP) phase was presented. EMPs promote HAP formation and inhibit the growth of OCP on the (010) plane. It is discussed that the organized Amelogenin/Amorphous Calcium Phosphate might be the precursor to the bundled HAP crystal prism. The study benefits the understanding of biomineralization of tooth enamel. - Highlights: ► An aligned hydroxyapatite crystal bundled by rod-like nanosize crystals was obtained. ► An organized Amel/ACP would be the precursor of the bundled hydroxyapatite crystal prism. ► EMPs inhibit the growth of octacalcium phosphate in a defined plane.

RNA-binding IMPs promote cell adhesion and invadopodia formation

DEFF Research Database (Denmark)

Vikesaa, Jonas; Hansen, Thomas V O; Jønson, Lars

2006-01-01

Oncofetal RNA-binding IMPs have been implicated in mRNA localization, nuclear export, turnover and translational control. To depict the cellular actions of IMPs, we performed a loss-of-function analysis, which showed that IMPs are necessary for proper cell adhesion, cytoplasmic spreading and inva......Oncofetal RNA-binding IMPs have been implicated in mRNA localization, nuclear export, turnover and translational control. To depict the cellular actions of IMPs, we performed a loss-of-function analysis, which showed that IMPs are necessary for proper cell adhesion, cytoplasmic spreading...... and invadopodia formation. Loss of IMPs was associated with a coordinate downregulation of mRNAs encoding extracellular matrix and adhesion proteins. The transcripts were present in IMP RNP granules, implying that IMPs were directly involved in the post-transcriptional control of the transcripts. In particular......-mediated invadopodia formation. Taken together, our results indicate that RNA-binding proteins exert profound effects on cellular adhesion and invasion during development and cancer formation....

Heterogeneous and self-organizing mineralization of bone matrix promoted by hydroxyapatite nanoparticles.

Science.gov (United States)

Campi, G; Cristofaro, F; Pani, G; Fratini, M; Pascucci, B; Corsetto, P A; Weinhausen, B; Cedola, A; Rizzo, A M; Visai, L; Rea, G

2017-11-16

The mineralization process is crucial to the load-bearing characteristics of the bone extracellular matrix. In this work, we have studied the spatiotemporal dynamics of mineral deposition by human bone marrow mesenchymal stem cells differentiating toward osteoblasts promoted by the presence of exogenous hydroxyapatite nanoparticles. At the molecular level, the added nanoparticles positively modulated the expression of bone-specific markers and enhanced calcified matrix deposition during osteogenic differentiation. The nucleation, growth and spatial arrangement of newly deposited hydroxyapatite nanocrystals have been evaluated using scanning micro X-ray diffraction and scanning micro X-ray fluorescence. As leading results, we have found the emergence of a complex scenario where the spatial organization and temporal evolution of the process exhibit heterogeneous and self-organizing dynamics. At the same time the possibility of controlling the differentiation kinetics, through the addition of synthetic nanoparticles, paves the way to empower the generation of more structured bone scaffolds in tissue engineering and to design new drugs in regenerative medicine.

Cadherin adhesion, tissue tension, and noncanonical Wnt signaling regulate fibronectin matrix organization.

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Dzamba, Bette J; Jakab, Karoly R; Marsden, Mungo; Schwartz, Martin A; DeSimone, Douglas W

2009-03-01

In this study we demonstrate that planar cell polarity signaling regulates morphogenesis in Xenopus embryos in part through the assembly of the fibronectin (FN) matrix. We outline a regulatory pathway that includes cadherin adhesion and signaling through Rac and Pak, culminating in actin reorganization, myosin contractility, and tissue tension, which, in turn, directs the correct spatiotemporal localization of FN into a fibrillar matrix. Increased mechanical tension promotes FN fibril assembly in the blastocoel roof (BCR), while reduced BCR tension inhibits matrix assembly. These data support a model for matrix assembly in tissues where cell-cell adhesions play an analogous role to the focal adhesions of cultured cells by transferring to integrins the tension required to direct FN fibril formation at cell surfaces.

Multi-protein delivery by nanodiamonds promotes bone formation.

Science.gov (United States)

Moore, L; Gatica, M; Kim, H; Osawa, E; Ho, D

2013-11-01

Bone morphogenetic proteins (BMPs) are well-studied regulators of cartilage and bone development that have been Food and Drug Administration (FDA)-approved for the promotion of bone formation in certain procedures. BMPs are seeing more use in oral and maxillofacial surgeries because of recent FDA approval of InFUSE(®) for sinus augmentation and localized alveolar ridge augmentation. However, the utility of BMPs in medical and dental applications is limited by the delivery method. Currently, BMPs are delivered to the surgical site by the implantation of bulky collagen sponges. Here we evaluate the potential of detonation nanodiamonds (NDs) as a delivery vehicle for BMP-2 and basic fibroblast growth factor (bFGF). Nanodiamonds are biocompatible, 4- to 5-nm carbon nanoparticles that have previously been used to deliver a wide variety of molecules, including proteins and peptides. We find that both BMP-2 and bFGF are readily loaded onto NDs by physisorption, forming a stable colloidal solution, and are triggered to release in slightly acidic conditions. Simultaneous delivery of BMP-2 and bFGF by ND induces differentiation and proliferation in osteoblast progenitor cells. Overall, we find that NDs provide an effective injectable alternative for the delivery of BMP-2 and bFGF to promote bone formation.

Fibrin promotes proliferation and matrix production of intervertebral disc cells cultured in three-dimensional poly(lactic-co-glycolic acid) scaffold.

Science.gov (United States)

Sha'ban, Munirah; Yoon, Sun Jung; Ko, Youn Kyung; Ha, Hyun Jung; Kim, Soon Hee; So, Jung Won; Idrus, Ruszymah Bt Hj; Khang, Gilson

2008-01-01

Previously, we have proven that fibrin and poly(lactic-co-glycolic acid) (PLGA) scaffolds facilitate cell proliferation, matrix production and early chondrogenesis of rabbit articular chondrocytes in in vitro and in vivo experiments. In this study, we evaluated the potential of fibrin/PLGA scaffold for intervertebral disc (IVD) tissue engineering using annulus fibrosus (AF) and nucleus pulposus (NP) cells in relation to potential clinical application. PLGA scaffolds were soaked in cells-fibrin suspension and polymerized by dropping thrombin-sodium chloride (CaCl(2)) solution. A PLGA-cell complex without fibrin was used as control. Higher cellular proliferation activity was observed in fibrin/PLGA-seeded AF and NP cells at each time point of 3, 7, 14 and 7 days using the MTT assay. After 3 weeks in vitro incubation, fibrin/PLGA exhibited a firmer gross morphology than PLGA groups. A significant cartilaginous tissue formation was observed in fibrin/PLGA, as proven by the development of cells cluster of various sizes and three-dimensional (3D) cartilaginous histoarchitecture and the presence of proteoglycan-rich matrix and glycosaminoglycan (GAG). The sGAG production measured by 1,9-dimethylmethylene blue (DMMB) assay revealed greater sGAG production in fibrin/PLGA than PLGA group. Immunohistochemical analyses showed expressions of collagen type II, aggrecan core protein and collagen type I genes throughout in vitro culture in both fibrin/PLGA and PLGA. In conclusion, fibrin promotes cell proliferation, stable in vitro tissue morphology, superior cartilaginous tissue formation and sGAG production of AF and NP cells cultured in PLGA scaffold. The 3D porous PLGA scaffold-cell complexes using fibrin can provide a vehicle for delivery of cells to regenerate tissue-engineered IVD tissue.

Interaction of Munc18c and syntaxin4 facilitates invadopodium formation and extracellular matrix invasion of tumor cells.

Science.gov (United States)

Brasher, Megan I; Martynowicz, David M; Grafinger, Olivia R; Hucik, Andrea; Shanks-Skinner, Emma; Uniacke, James; Coppolino, Marc G

2017-09-29

Tumor cell invasion involves targeted localization of proteins required for interactions with the extracellular matrix and for proteolysis. The localization of many proteins during these cell-extracellular matrix interactions relies on membrane trafficking mediated in part by SNAREs. The SNARE protein syntaxin4 (Stx4) is involved in the formation of invasive structures called invadopodia; however, it is unclear how Stx4 function is regulated during tumor cell invasion. Munc18c is known to regulate Stx4 activity, and here we show that Munc18c is required for Stx4-mediated invadopodium formation and cell invasion. Biochemical and microscopic analyses revealed a physical association between Munc18c and Stx4, which was enhanced during invadopodium formation, and that a reduction in Munc18c expression decreases invadopodium formation. We also found that an N-terminal Stx4-derived peptide associates with Munc18c and inhibits endogenous interactions of Stx4 with synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2). Furthermore, expression of the Stx4 N-terminal peptide decreased invadopodium formation and cell invasion in vitro Of note, cells expressing the Stx4 N-terminal peptide exhibited impaired trafficking of membrane type 1 matrix metalloproteinase (MT1-MMP) and EGF receptor (EGFR) to the cell surface during invadopodium formation. Our findings implicate Munc18c as a regulator of Stx4-mediated trafficking of MT1-MMP and EGFR, advancing our understanding of the role of SNARE function in the localization of proteins that drive tumor cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Electron microscopic studies of the matrix formation of hard tissue organized cell

International Nuclear Information System (INIS)

Chou, Ching-Eng

1982-01-01

In order to study the functions of odontoblast, especially on the matrix formation, odontoblasts of rats' incisor and molar teeth were used. The animals were sacrificed 5 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours and 24 hours after 3 H-proline administration to obtain the specimen. The specimens were processed for electron microscopic autoradiography. The following results were obtained. 1. 5 minutes after 3 H-proline administration: Silver grains indicated 3 H-proline uptake were already noted within the cells and localized in the rough surfaced endoplasmic reticulum and surrounding ribosomes, partially within the karyoplasm. 2. 15 minutes after 3 H-proline administration: The number of silver grains were generally increased as compared with the findings obtained in 5 minutes. The localization moved to the Golgi apparatus and their surroundings. 3. 30 minutes after 3 H-proline administration: Silver grains obtained in Tome's fibers area and some in predentin. In this area granules derived from Golgi body were found. 4. 1 hour after 3 H-proline administration: The number of silver grains were generally decreased and more pronounced movement toward predentin, the marked movement of silver grains were obtained onto the collagen fibers and surroundings. 5. 2 hours after 3 H-proline administration: Silver grains moved to the calcified area and there collagen fibers became more remarkable. 6. 24 hours after 3 H-proline administration: No silver grains were founded in the odontoblast side but deposited in the predentin calcified area with stable condition. Based on the results of these observations, odontoblasts were shown to perform the function of synthesis, storage, transportation and control of collagen formation in addition to the role of matrix formation. (author)

Extracellular matrix formation enhances the ability of Streptococcus pneumoniae to cause invasive disease.

Directory of Open Access Journals (Sweden)

Claudia Trappetti

Full Text Available During infection, pneumococci exist mainly in sessile biofilms rather than in planktonic form, except during sepsis. However, relatively little is known about how biofilms contribute to pneumococcal pathogenesis. Here, we carried out a biofilm assay on opaque and transparent variants of a clinical serotype 19F strain WCH159. After 4 days incubation, scanning electron microscopy revealed that opaque biofilm bacteria produced an extracellular matrix, whereas the transparent variant did not. The opaque biofilm-derived bacteria translocated from the nasopharynx to the lungs and brain of mice, and showed 100-fold greater in vitro adherence to A549 cells than transparent bacteria. Microarray analysis of planktonic and sessile bacteria from transparent and opaque variants showed differential gene expression in two operons: the lic operon, which is involved in choline uptake, and in the two-component system, ciaRH. Mutants of these genes did not form an extracellular matrix, could not translocate from the nasopharynx to the lungs or the brain, and adhered poorly to A549 cells. We conclude that only the opaque phenotype is able to form extracellular matrix, and that the lic operon and ciaRH contribute to this process. We propose that during infection, extracellular matrix formation enhances the ability of pneumococci to cause invasive disease.

Regulation of extracellular matrix vesicles via rapid responses to steroid hormones during endochondral bone formation.

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Asmussen, Niels; Lin, Zhao; McClure, Michael J; Schwartz, Zvi; Boyan, Barbara D

2017-12-09

Endochondral bone formation is a precise and highly ordered process whose exact regulatory framework is still being elucidated. Multiple regulatory pathways are known to be involved. In some cases, regulation impacts gene expression, resulting in changes in chondrocyte phenotypic expression and extracellular matrix synthesis. Rapid regulatory mechanisms are also involved, resulting in release of enzymes, factors and micro RNAs stored in extracellular matrisomes called matrix vesicles. Vitamin D metabolites modulate endochondral development via both genomic and rapid membrane-associated signaling pathways. 1α,25-dihydroxyvitamin D3 [1α,25(OH) 2 D 3 ] acts through the vitamin D receptor (VDR) and a membrane associated receptor, protein disulfide isomerase A3 (PDIA3). 24R,25-dihydroxyvitamin D3 [24R,25(OH) 2 D 3 ] affects primarily chondrocytes in the resting zone (RC) of the growth plate, whereas 1α,25(OH) 2 D 3 affects cells in the prehypertrophic and upper hypertrophic cell zones (GC). This includes genomically directing the cells to produce matrix vesicles with zone specific characteristics. In addition, vitamin D metabolites produced by the cells interact directly with the matrix vesicle membrane via rapid signal transduction pathways, modulating their activity in the matrix. The matrix vesicle payload is able to rapidly impact the extracellular matrix via matrix processing enzymes as well as providing a feedback mechanism to the cells themselves via the contained micro RNAs. Copyright © 2017. Published by Elsevier Inc.

Formation of failure matrix and failure–free control algorithm for multi–sectioned Switched–reluctance drive

International Nuclear Information System (INIS)

Odnokopylov, G; Rozayev, I

2014-01-01

We review fault-tolerant switched reluctance drive with sectioning of the three–phase stator winding. In the operating process of an electric drive, there will be continuous monitoring of the operating state on the basis of a developed algorithm to analyse drive operability and formation tabulate a failure matrix. The paper introduces a failure–free control algorithm for multi–section switch – reluctance motor with formation the assignment values of amplitude phase currents taking into account the failure matrix. We show that in an emergency such single failure or multiple failure in switched–reluctance drive it is possible to provide reduction of torque fall and pro–gressively stock depletion with providing fault–tolerance of drive system. A method of residual life evaluation is proposed on the basis of calculating the coefficient of operability of the electric drive system that gives possibility to control the endurance of electric drive in real time from operational to completely unusable

Quadrupole corrections to matrix elements of transitions in resonant reactions of muonic molecule formation

International Nuclear Information System (INIS)

Faifman, M.P.; Strizh, T.A.; Armour, E.A.G.; Harston, M.R.

1996-01-01

The calculated resonant formation rates of the muonic molecules DDμ and DTμ are presented. The approach developed earlier for calculating the transition matrix elements in the dipole approximation has been extended to include the quadrupole terms in the multipole expansion of the interaction operator. The calculated dependence of the DTμ formation rates on the energies of the incident Tμ muonic atoms shows that the effect of including the quadrupole correction is to reduce the magnitude of the peak rates by about 20-30% at the different temperatures, compared to those calculated in the dipole approximation. The dependence on temperature for the DDμ formation rates is obtained with the differences between the presented and previous calculations being less than 5%. (orig.)

Decellularized matrix from tumorigenic human mesenchymal stem cells promotes neovascularization with galectin-1 dependent endothelial interaction.

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Jorge S Burns

Full Text Available BACKGROUND: Acquisition of a blood supply is fundamental for extensive tumor growth. We recently described vascular heterogeneity in tumours derived from cell clones of a human mesenchymal stem cell (hMSC strain (hMSC-TERT20 immortalized by retroviral vector mediated human telomerase (hTERT gene expression. Histological analysis showed that cells of the most vascularized tumorigenic clone, -BD11 had a pericyte-like alpha smooth muscle actin (ASMA+ and CD146+ positive phenotype. Upon serum withdrawal in culture, -BD11 cells formed cord-like structures mimicking capillary morphogenesis. In contrast, cells of the poorly tumorigenic clone, -BC8 did not stain for ASMA, tumours were less vascularized and serum withdrawal in culture led to cell death. By exploring the heterogeneity in hMSC-TERT20 clones we aimed to understand molecular mechanisms by which mesenchymal stem cells may promote neovascularization. METHODOLOGY/PRINCIPAL FINDINGS: Quantitative qRT-PCR analysis revealed similar mRNA levels for genes encoding the angiogenic cytokines VEGF and Angiopoietin-1 in both clones. However, clone-BD11 produced a denser extracellular matrix that supported stable ex vivo capillary morphogenesis of human endothelial cells and promoted in vivo neovascularization. Proteomic characterization of the -BD11 decellularized matrix identified 50 extracellular angiogenic proteins, including galectin-1. siRNA knock down of galectin-1 expression abrogated the ex vivo interaction between decellularized -BD11 matrix and endothelial cells. More stable shRNA knock down of galectin-1 expression did not prevent -BD11 tumorigenesis, but greatly reduced endothelial migration into -BD11 cell xenografts. CONCLUSIONS: Decellularized hMSC matrix had significant angiogenic potential with at least 50 angiogenic cell surface and extracellular proteins, implicated in attracting endothelial cells, their adhesion and activation to form tubular structures. hMSC -BD11 surface galectin-1

Decellularized Matrix from Tumorigenic Human Mesenchymal Stem Cells Promotes Neovascularization with Galectin-1 Dependent Endothelial Interaction

Science.gov (United States)

Burns, Jorge S.; Kristiansen, Malthe; Kristensen, Lars P.; Larsen, Kenneth H.; Nielsen, Maria O.; Christiansen, Helle; Nehlin, Jan; Andersen, Jens S.; Kassem, Moustapha

2011-01-01

Background Acquisition of a blood supply is fundamental for extensive tumor growth. We recently described vascular heterogeneity in tumours derived from cell clones of a human mesenchymal stem cell (hMSC) strain (hMSC-TERT20) immortalized by retroviral vector mediated human telomerase (hTERT) gene expression. Histological analysis showed that cells of the most vascularized tumorigenic clone, -BD11 had a pericyte-like alpha smooth muscle actin (ASMA+) and CD146+ positive phenotype. Upon serum withdrawal in culture, -BD11 cells formed cord-like structures mimicking capillary morphogenesis. In contrast, cells of the poorly tumorigenic clone, -BC8 did not stain for ASMA, tumours were less vascularized and serum withdrawal in culture led to cell death. By exploring the heterogeneity in hMSC-TERT20 clones we aimed to understand molecular mechanisms by which mesenchymal stem cells may promote neovascularization. Methodology/Principal Findings Quantitative qRT-PCR analysis revealed similar mRNA levels for genes encoding the angiogenic cytokines VEGF and Angiopoietin-1 in both clones. However, clone-BD11 produced a denser extracellular matrix that supported stable ex vivo capillary morphogenesis of human endothelial cells and promoted in vivo neovascularization. Proteomic characterization of the -BD11 decellularized matrix identified 50 extracellular angiogenic proteins, including galectin-1. siRNA knock down of galectin-1 expression abrogated the ex vivo interaction between decellularized -BD11 matrix and endothelial cells. More stable shRNA knock down of galectin-1 expression did not prevent -BD11 tumorigenesis, but greatly reduced endothelial migration into -BD11 cell xenografts. Conclusions Decellularized hMSC matrix had significant angiogenic potential with at least 50 angiogenic cell surface and extracellular proteins, implicated in attracting endothelial cells, their adhesion and activation to form tubular structures. hMSC -BD11 surface galectin-1 expression was

A unified approach for description of gas hydrate formation kinetics in the presence of kinetic promoters in gas hydrate converters

International Nuclear Information System (INIS)

ZareNezhad, Bahman; Varaminian, Farshad

2013-01-01

Highlights: • A unified kinetic model for description of promoted and non-promoted gas hydrate formation processes is presented. • Effects of impeller speed, promoter concentration and different kinetic promoters are investigated. • A unique region of gas hydrate formation is identified regarding gas hydrate formation processes. • The proposed model is useful for understanding the behavior of gas hydrate formation processes and design of GTH converters. - Abstract: The kinetic promoters have found wide applications in enhancing the rate of energy conversion and storage via gas hydrate formation processes. Effects of different kinetic promoters such as anionic surfactants sodium dodecyl sulfate (SDS), dodecylbenzene sulfonic acid (DBSA), and sodium dodecyl benzene sulfonate (SDBS); cationic surfactants, Cetyl trimethyl ammonium bromide (CTAB), dodecyl trimethyl ammonium bromide (DTAB) and non-ionic surfactants, alkylpolyglucoside (APG), dodecyl polysaccharide glycoside (DPG), TritonX-100 (TX100) on methane (CH 4 ), ethane (C 2 H 6 ) and propane (C 3 H 8 ) gas hydrate formation processes are investigated in this work. A macroscopic kinetic model based on the time variations of reaction chemical potential is also presented for global description of gas hydrate formation processes. Experimental gas hydrate formation data are employed to validate the proposed kinetic model. Effects of promoter’s concentrations and agitation intensities on the gas consumption profiles are also investigated. A universal correlation and a unified kinetic map have been proposed for macroscopic description of gas hydrate formation kinetics in the presence or absence of kinetic promoters. According to the presented unified kinetic map, a unique region of gas hydrate formation is identified for the first time. For negligible amounts of kinetic promoters, the presented region disappears and approaches to a unique path at high agitation intensities. The presented unified approach is

Interplay of Matrix Stiffness and c-SRC in Hepatic Fibrosis

DEFF Research Database (Denmark)

Görtzen, Jan; Schierwagen, Robert; Bierwolf, Jeanette

2015-01-01

. This study investigated the interaction of c-SRC and RhoA under different matrix stiffness conditions. METHODS: Liver fibrosis was induced in rats using bile duct ligation (BDL), thioacetamide (TAA) or carbon tetrachloride (CCl4) models. mRNA levels of albumin, PDGF-R, RHOA, COL1A1, and αSMA were analyzed......INTRODUCTION: In liver fibrosis activation of hepatic stellate cells (HSC) comprises phenotypical change into profibrotic and myofibroplastic cells with increased contraction and secretion of extracellular matrix (ECM) proteins. The small GTPase RhoA orchestrates cytoskeleton formation, migration......, and mobility via non-receptor tyrosine-protein kinase c-SRC (cellular sarcoma) in different cells. Furthermore, RhoA and its downstream effector Rho-kinase also play a crucial role in hepatic stellate cells and hepatic fibrogenesis. Matrix stiffness promotes HSC activation via cytoskeleton modulation...

Thyroid dysfunction, either hyper or hypothyroidism, promotes gallstone formation by different mechanisms*

Science.gov (United States)

Wang, Yong; Yu, Xing; Zhao, Qun-zi; Zheng, Shu; Qing, Wen-jie; Miao, Chun-di; Sanjay, Jaiswal

2016-01-01

We have investigated comprehensively the effects of thyroid function on gallstone formation in a mouse model. Gonadectomized gallstone-susceptible male C57BL/6 mice were randomly distributed into three groups each of which received an intervention to induce hyperthyroidism, hypothyroidism, or euthyroidism. After 5 weeks of feeding a lithogenic diet of 15% (w/w) butter fat, 1% (w/w) cholesterol, and 0.5% (w/w) cholic acid, mice were killed for further experiments. The incidence of cholesterol monohydrate crystal formation was 100% in mice with hyperthyroidism, 83% in hypothyroidism, and 33% in euthyroidism, the differences being statistically significant. Among the hepatic lithogenic genes, Trβ was found to be up-regulated and Rxr down-regulated in the mice with hypothyroidism. In contrast, Lxrα, Rxr, and Cyp7α1 were up-regulated and Fxr down-regulated in the mice with hyperthyroidism. In conclusion, thyroid dysfunction, either hyperthyroidism or hypothyroidism, promotes the formation of cholesterol gallstones in C57BL/6 mice. Gene expression differences suggest that thyroid hormone disturbance leads to gallstone formation in different ways. Hyperthyroidism induces cholesterol gallstone formation by regulating expression of the hepatic nuclear receptor genes such as Lxrα and Rxr, which are significant in cholesterol metabolism pathways. However, hypothyroidism induces cholesterol gallstone formation by promoting cholesterol biosynthesis. PMID:27381728

Bile canaliculi formation and biliary transport in 3D sandwich-cultured hepatocytes in dependence of the extracellular matrix composition.

Science.gov (United States)

Deharde, Daniela; Schneider, Christin; Hiller, Thomas; Fischer, Nicolas; Kegel, Victoria; Lübberstedt, Marc; Freyer, Nora; Hengstler, Jan G; Andersson, Tommy B; Seehofer, Daniel; Pratschke, Johann; Zeilinger, Katrin; Damm, Georg

2016-10-01

Primary human hepatocytes (PHH) are still considered as gold standard for investigation of in vitro metabolism and hepatotoxicity in pharmaceutical research. It has been shown that the three-dimensional (3D) cultivation of PHH in a sandwich configuration between two layers of extracellular matrix (ECM) enables the hepatocytes to adhere three dimensionally leading to formation of in vivo like cell-cell contacts and cell-matrix interactions. The aim of the present study was to investigate the influence of different ECM compositions on morphology, cellular arrangement and bile canaliculi formation as well as bile excretion processes in PHH sandwich cultures systematically. Freshly isolated PHH were cultured for 6 days between two ECM layers made of collagen and/or Matrigel in four different combinations. The cultures were investigated by phase contrast microscopy and immunofluorescence analysis with respect to cell-cell connections, repolarization as well as bile canaliculi formation. The influence of the ECM composition on cell activity and viability was measured using the XTT assay and a fluorescent dead or alive assay. Finally, the bile canalicular transport was analyzed by live cell imaging to monitor the secretion and accumulation of the fluorescent substance CDF in bile canaliculi. Using collagen and Matrigel in different compositions in sandwich cultures of hepatocytes, we observed differences in morphology, cellular arrangement and cell activity of PHH in dependence of the ECM composition. Sandwich-cultured hepatocytes with an underlay of collagen seem to represent the best in vivo tissue architecture in terms of formation of trabecular cell arrangement. Cultures overlaid with collagen were characterized by the formation of abundant bile canaliculi, while the bile canaliculi network in hepatocytes cultured on a layer of Matrigel and overlaid with collagen showed the most branched and stable canalicular network. All cultures showed a time-dependent leakage of

HOXB4 Promotes Hemogenic Endothelium Formation without Perturbing Endothelial Cell Development

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Nadine Teichweyde

2018-03-01

Full Text Available Summary: Generation of hematopoietic stem cells (HSCs from pluripotent stem cells, in vitro, holds great promise for regenerative therapies. Primarily, this has been achieved in mouse cells by overexpression of the homeotic selector protein HOXB4. The exact cellular stage at which HOXB4 promotes hematopoietic development, in vitro, is not yet known. However, its identification is a prerequisite to unambiguously identify the molecular circuits controlling hematopoiesis, since the activity of HOX proteins is highly cell and context dependent. To identify that stage, we retrovirally expressed HOXB4 in differentiating mouse embryonic stem cells (ESCs. Through the use of Runx1(−/− ESCs containing a doxycycline-inducible Runx1 coding sequence, we uncovered that HOXB4 promoted the formation of hemogenic endothelium cells without altering endothelial cell development. Whole-transcriptome analysis revealed that its expression mediated the upregulation of transcription of core transcription factors necessary for hematopoiesis, culminating in the formation of blood progenitors upon initiation of Runx1 expression. : In this article, Klump and colleagues demonstrate that the human homeotic selector protein HOXB4 promotes ESC-derived hematopoiesis by inducing hemogenic endothelium formation, in vitro. It propels hematopoietic specification by upregulating the transcription of genes essential for hematopoietic development, such as those encoding members of the so-called heptad transcription factors. Keywords: HOXB4, hematopoietic stem cells, hemangioblast, hemogenic endothelium, hematopoietic specification, EHT, RUNX1, pluripotent stem cells

Surface Topography and Mechanical Strain Promote Keratocyte Phenotype and Extracellular Matrix Formation in a Biomimetic 3D Corneal Model.

Science.gov (United States)

Zhang, Wei; Chen, Jialin; Backman, Ludvig J; Malm, Adam D; Danielson, Patrik

2017-03-01

The optimal functionality of the native corneal stroma is mainly dependent on the well-ordered arrangement of extracellular matrix (ECM) and the pressurized structure. In order to develop an in vitro corneal model, it is crucial to mimic the in vivo microenvironment of the cornea. In this study, the influence of surface topography and mechanical strain on keratocyte phenotype and ECM formation within a biomimetic 3D corneal model is studied. By modifying the surface topography of materials, it is found that patterned silk fibroin film with 600 grooves mm -1 optimally supports cell alignment and ECM arrangement. Furthermore, treatment with 3% dome-shaped mechanical strain, which resembles the shape and mechanics of native cornea, significantly enhances the expression of keratocyte markers as compared to flat-shaped strain. Accordingly, a biomimetic 3D corneal model, in the form of a collagen-modified, silk fibroin-patterned construct subjected to 3% dome-shaped strain, is created. Compared to traditional 2D cultures, it supports a significantly higher expression of keratocyte and ECM markers, and in conclusion better maintains keratocyte phenotype, alignment, and fusiform cell shape. Therefore, the novel biomimetic 3D corneal model developed in this study serves as a useful in vitro 3D culture model to improve current 2D cultures for corneal studies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells☆

Science.gov (United States)

Nalluri, Sandeep M.; Krishnan, G. Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A.; Yang, Shuying; Sarkar, Debanjan

2016-01-01

Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell–matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell–cell and cell–matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell–matrix interaction, and cell–cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. PMID:26046282

Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.

Science.gov (United States)

Nalluri, Sandeep M; Krishnan, G Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A; Yang, Shuying; Sarkar, Debanjan

2015-09-01

Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Biofilms of vaginal Lactobacillus reuteri CRL 1324 and Lactobacillus rhamnosus CRL 1332: kinetics of formation and matrix characterization.

Science.gov (United States)

Leccese Terraf, María Cecilia; Juárez Tomás, María Silvina; Rault, Lucie; Le Loir, Yves; Even, Sergine; Nader-Macías, María Elena Fátima

2016-09-01

Adhesion and biofilm formation are strain properties that reportedly contribute to the permanence of lactobacilli in the human vagina. The kinetics of biofilm formation and the chemical nature of the biofilm matrix formed by Lactobacillus reuteri CRL (Centro de Referencia para Lactobacilos Culture Collection) 1324 and Lactobacillus rhamnosus CRL 1332, vaginal beneficial strains, were evaluated in this work. Crystal violet-stained microplate assay and techniques of epifluorescence, electron and confocal microscopy were applied. The highest density and complexity of biofilms of both vaginal lactobacilli were observed at 72 h of incubation. Protease, proteinase K, α-chymotrypsin and trypsin treatments efficiently detached L. reuteri CRL 1324 biofilm that was also partially affected by α-amylase. However, L. rhamnosus CRL 1332 biofilm was slightly affected by protease, proteinase K and α-amylase. Confocal microscopy revealed greater amount of polysaccharides in L. rhamnosus CRL 1332 biofilm matrix than in L. reuteri CRL 1324 biofilm matrix. The results indicate that proteins are one of the main components of the L. reuteri CRL 1324 biofilm, while the biofilm matrix of L. rhamnosus CRL 1332 is composed of carbohydrates and proteins. The results obtained support the knowledge, understanding and characterization of two biofilm-forming vaginal Lactobacillus strains.

The extracellular matrix of the lung and its role in edema formation

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Paolo Pelosi

2007-06-01

Full Text Available The extracellular matrix is composed of a three-dimensional fiber mesh filled with different macromolecules such as: collagen (mainly type I and III, elastin, glycosaminoglycans, and proteoglycans. In the lung, the extracellular matrix has several functions which provide: 1 mechanical tensile and compressive strength and elasticity, 2 low mechanical tissue compliance contributing to the maintenance of normal interstitial fluid dynamics, 3 low resistive pathway for an effective gas exchange, d control of cell behavior by the binding of growth factors, chemokines, cytokines and the interaction with cell-surface receptors, and e tissue repair and remodeling. Fragmentation and disorganization of extracellular matrix components comprises the protective role of the extracellular matrix, leading to interstitial and eventually severe lung edema. Thus, once conditions of increased microvascular filtration are established, matrix remodeling proceeds fairly rapidly due to the activation of proteases. Conversely, a massive matrix deposition of collagen fiber decreases interstitial compliance and therefore makes the tissue safety factor stronger. As a result, changes in lung extracellular matrix significantly affect edema formation and distribution in the lung.A matriz extracelular é um aglomerado tridimensional demacromoléculas composta por: fibras colágenas (principalmente, tipos I e III, elastina, glicosaminoglicanos e proteoglicanos. No pulmão, a matriz extracelular tem várias funções, tais como: 1 promover estresse tensil e elasticidade tecidual, 2 contribuir para a manutenção da dinâmica de fluidos no interstício, 3 propiciar efetiva troca gasosa, 4 controlar a função celular através de sua ligação com fatores de crescimento, quimiocinas, citocinas e interação com receptores de superfície, e 5 remodelamento e reparo tecidual. A fragmentação e a desorganização da matriz extracelular pode acarretar edema intersticial e

A synthetic peptide from the COOH-terminal heparin-binding domain of fibronectin promotes focal adhesion formation

DEFF Research Database (Denmark)

Woods, A; McCarthy, J B; Furcht, L T

1993-01-01

Cell adhesion to extracellular matrix molecules such as fibronectin involves complex transmembrane signaling processes. Attachment and spreading of primary fibroblasts can be promoted by interactions of cell surface integrins with RGD-containing fragments of fibronectin, but the further process o...

Capillary network formation from dispersed endothelial cells: Influence of cell traction, cell adhesion, and extracellular matrix rigidity

Science.gov (United States)

Ramos, João R. D.; Travasso, Rui; Carvalho, João

2018-01-01

The formation of a functional vascular network depends on biological, chemical, and physical processes being extremely well coordinated. Among them, the mechanical properties of the extracellular matrix and cell adhesion are fundamental to achieve a functional network of endothelial cells, able to fully cover a required domain. By the use of a Cellular Potts Model and Finite Element Method it is shown that there exists a range of values of endothelial traction forces, cell-cell adhesion, and matrix rigidities where the network can spontaneously be formed, and its properties are characterized. We obtain the analytical relation that the minimum traction force required for cell network formation must obey. This minimum value for the traction force is approximately independent on the considered cell number and cell-cell adhesion. We quantify how these two parameters influence the morphology of the resulting networks (size and number of meshes).

Matrix Metalloproteinases: Inflammatory Regulators of Cell Behaviors in Vascular Formation and Remodeling

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Qishan Chen

2013-01-01

Full Text Available Abnormal angiogenesis and vascular remodeling contribute to pathogenesis of a number of disorders such as tumor, arthritis, atherosclerosis, restenosis, hypertension, and neurodegeneration. During angiogenesis and vascular remodeling, behaviors of stem/progenitor cells, endothelial cells (ECs, and vascular smooth muscle cells (VSMCs and its interaction with extracellular matrix (ECM play a critical role in the processes. Matrix metalloproteinases (MMPs, well-known inflammatory mediators are a family of zinc-dependent proteolytic enzymes that degrade various components of ECM and non-ECM molecules mediating tissue remodeling in both physiological and pathological processes. MMPs including MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-12, and MT1-MMP, are stimulated and activated by various stimuli in vascular tissues. Once activated, MMPs degrade ECM proteins or other related signal molecules to promote recruitment of stem/progenitor cells and facilitate migration and invasion of ECs and VSMCs. Moreover, vascular cell proliferation and apoptosis can also be regulated by MMPs via proteolytically cleaving and modulating bioactive molecules and relevant signaling pathways. Regarding the importance of vascular cells in abnormal angiogenesis and vascular remodeling, regulation of vascular cell behaviors through modulating expression and activation of MMPs shows therapeutic potential.

Effect of multicomponent InAsSbP matrix surface on formation of InSb quantum dots at MOVPE growth

International Nuclear Information System (INIS)

Romanov, V. V.; Dement’ev, P. A.; Moiseev, K. D.

2016-01-01

Indium-antimonide quantum dots (7–9 × 10"9 cm"2) are produced on an InAs(001) substrate by metal-organic vapor-phase epitaxy at a temperature of T = 440°C. Epitaxial deposition occurred simultaneously onto an InAs binary matrix and an InAsSbP quaternary alloy matrix layer lattice-matched to the InAs substrate in terms of the lattice parameter. Transformation of the quantum-dot shape and size is studied in relation to the chemical composition of the working matrix surface, onto which the quantum dots are deposited. The use of a multicomponent layer makes it possible to control the lattice parameter of the matrix and the strains produced in the system during the formation of self-assembled quantum dots.

Mesenchymal stem cell-derived extracellular matrix enhances chondrogenic phenotype of and cartilage formation by encapsulated chondrocytes in vitro and in vivo.

Science.gov (United States)

Yang, Yuanheng; Lin, Hang; Shen, He; Wang, Bing; Lei, Guanghua; Tuan, Rocky S

2018-03-15

Mesenchymal stem cell derived extracellular matrix (MSC-ECM) is a natural biomaterial with robust bioactivity and good biocompatibility, and has been studied as a scaffold for tissue engineering. In this investigation, we tested the applicability of using decellularized human bone marrow derived MSC-ECM (hBMSC-ECM) as a culture substrate for chondrocyte expansion in vitro, as well as a scaffold for chondrocyte-based cartilage repair. hBMSC-ECM deposited by hBMSCs cultured on tissue culture plastic (TCP) was harvested, and then subjected to a decellularization process to remove hBMSCs. Compared with chondrocytes grown on TCP, chondrocytes seeded onto hBMSC-ECM exhibited significantly increased proliferation rate, and maintained better chondrocytic phenotype than TCP group. After being expanded to the same cell number and placed in high-density micromass cultures, chondrocytes from the ECM group showed better chondrogenic differentiation profile than those from the TCP group. To test cartilage formation ability, composites of hBMSC-ECM impregnated with chondrocytes were subjected to brief trypsin treatment to allow cell-mediated contraction, and folded to form 3-dimensional chondrocyte-impregnated hBMSC-ECM (Cell/ECM constructs). Upon culture in vitro in chondrogenic medium for 21 days, robust cartilage formation was observed in the Cell/ECM constructs. Similarly prepared Cell/ECM constructs were tested in vivo by subcutaneous implantation into SCID mice. Prominent cartilage formation was observed in the implanted Cell/ECM constructs 14 days post-implantation, with higher sGAG deposition compared to controls consisting of chondrocyte cell sheets. Taken together, these findings demonstrate that hBMSC-ECM is a superior culture substrate for chondrocyte expansion and a bioactive matrix potentially applicable for cartilage regeneration in vivo. Current cell-based treatments for focal cartilage defects face challenges, including chondrocyte dedifferentiation, need for

Coke formation on hydrodesulphurization catalysts. [Including effects of different promoters

Energy Technology Data Exchange (ETDEWEB)

Ternan, M.; Furimsky, E.; Parsons, B.I.

1979-02-01

The extent of coke formation was measured on a number of different hydrodesulfurization catalysts, primarily as a function of the catalyst chemical composition. Variations in the concentration of MoO/sub 3/ on the alumina, the type of catalyst promoter, the promoter/MoO/sub 3/ ratio, the presulfiding material and the reaction temperature were made. Increases in the reaction rate caused by either changes in the catalyst composition or by moderate changes in the reaction temperature were compared to the catalyst coke content. It was suggested that two types of coke were present on the catalyst, a reactive coke which is subsequently converted to reaction products and an unreactive coke which blocks catalytic sites.

Tridax procumbens flavonoids promote osteoblast differentiation and bone formation

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Md. Abdullah Al Mamun

Full Text Available BACKGROUND: Tridaxprocumbens flavonoids (TPFs are well known for their medicinal properties among local natives. Besides traditionally used for dropsy, anemia, arthritis, gout, asthma, ulcer, piles, and urinary problems, it is also used in treating gastric problems, body pain, and rheumatic pains of joints. TPFs have been reported to increase osteogenic functioning in mesenchymal stem cells. Our previous study showed that TPFs were significantly suppressed the RANKL-induced differentiation of osteoclasts and bone resorption. However, the effects of TPFs to promote osteoblasts differentiation and bone formation remain unclear. TPFs were isolated from Tridax procumbens and investigated for their effects on osteoblasts differentiation and bone formation by using primary mouse calvarial osteoblasts RESULTS: TPFs promoted osteoblast differentiation in a dose-dependent manner demonstrated by up-regulation of alkaline phosphatase and osteocalcin. TPFs also upregulated osteoblast differentiation related genes, including osteocalcin, osterix, and Runx2 in primary osteoblasts. TPFs treated primary osteoblast cells showed significant upregulation of bone morphogenetic proteins (BMPs including Bmp-2, Bmp-4, and Bmp-7. Addition of noggin, a BMP specific-antagonist, inhibited TPFs induced upregulation of the osteocalcin, osterix, and Runx2 CONCLUSION: Our findings point towards the induction of osteoblast differentiation by TPFs and suggested that TPFs could be a potential anabolic agent to treat patients with bone loss-associated diseases such as osteoporosis

Regulation of Matrix Metalloproteinase-2 Activity by COX-2-PGE2-pAKT Axis Promotes Angiogenesis in Endometriosis

Science.gov (United States)

Ray, Amlan K.; DasMahapatra, Pramathes; Swarnakar, Snehasikta

2016-01-01

Endometriosis is characterized by the ectopic development of the endometrium which relies on angiogenesis. Although studies have identified the involvement of different matrix metalloproteinases (MMPs) in endometriosis, no study has yet investigated the role of MMP-2 in endometriosis-associated angiogenesis. The present study aims to understand the regulation of MMP-2 activity in endothelial cells and on angiogenesis during progression of ovarian endometriosis. Histological and biochemical data showed increased expressions of vascular endothelial growth factor (VEGF), VEGF receptor-2, cycloxygenase (COX)-2, von Willebrand factor along with angiogenesis during endometriosis progression. Women with endometriosis showed decreased MMP-2 activity in eutopic endometrium as compared to women without endometriosis. However, ectopic ovarian endometrioma showed significantly elevated MMP-2 activity with disease severity. In addition, increased MT1MMP and decreased tissue inhibitors of metalloproteinases (TIMP)-2 expressions were found in the late stages of endometriosis indicating more MMP-2 activation with disease progression. In vitro study using human endothelial cells showed that prostaglandin E2 (PGE2) significantly increased MMP-2 activity as well as tube formation. Inhibition of COX-2 and/or phosphorylated AKT suppressed MMP-2 activity and endothelial tube formation suggesting involvement of PGE2 in regulation of MMP-2 activity during angiogenesis. Moreover, specific inhibition of MMP-2 by chemical inhibitor significantly reduced cellular migration, invasion and tube formation. In ovo assay showed decreased angiogenic branching upon MMP-2 inhibition. Furthermore, a significant reduction of lesion numbers was observed upon inhibition of MMP-2 and COX-2 in mouse model of endometriosis. In conclusion, our study establishes the involvement of MMP-2 activity via COX-2-PGE2-pAKT axis in promoting angiogenesis during endometriosis progression. PMID:27695098

Matrix Gla Protein is Involved in Crystal Formation in Kidney of Hyperoxaluric Rats

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Xiuli Lu

2013-02-01

Full Text Available Background: Matrix Gla protein (MGP is a molecular determinant regulating vascular calcification of the extracellular matrix. However, it is still unclear how MGP may be invovled in crystal formation in the kidney of hyperoxaluric rats. Methods: Male Sprague-Dawley rats were divided into the hyperoxaluric group and control group. Hyperoxaluric rats were administrated by 0.75% ethylene glycol (EG for up to 8 weeks. Renal MGP expression was detected by the standard avidin-biotin complex (ABC method. Renal crystal deposition was observed by a polarizing microscope. Total RNA and protein from the rat kidney tissue were extracted. The levels of MGP mRNA and protein expression were analyzed by the real-time polymerase chain reaction (RT-PCR and Western blot. Results: Hyperoxaluria was induced successfully in rats. The MGP was polarly distributed, on the apical membrane of renal tubular epithelial cells, and was found in the ascending thick limbs of Henle's loop (cTAL and the distal convoluted tubule (DCT in hyperoxaluric rats, its expression however, was present in the medullary collecting duct (MCD in stone-forming rats. Crystals with multilaminated structure formed in the injurious renal tubules with lack of MGP expression.MGP mRNA expression was significantly upregulated by the crystals' stimulations. Conclusion: Our results suggested that the MGP was involved in crystals formation by the continuous expression, distributing it polarly in the renal tubular cells and binding directly to the crystals.

FORMATION AND FURTHER DEVELOPMENT OF MODERN PROMOTION OF PHARMACEUTICAL PRODUCTS

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Юрий Владимирович Тарасов

2014-02-01

Full Text Available The articles addresses key notions and elements of marketing of pharmaceutical companies. Key stages and particularities of formation of pharmaceutical marketing are considered. It is proved that in general pharmaceutical market is developing under general marketing rules, however while developing strategy of promotion of pharmaceutical products specific features of the industry must be taken into consideration. The authors describes specific features of modern pharmaceutical market, which must be considered while developing policy of promotion of pharmaceutical products.The analysis is made of modern state of Russian pharmaceutical industry, its place in world pharmaceutical market. It is found that development of pharmaceutical market is directly influenced by the reform of pharmaceutical industry initiated by the Government of our country in 2008. Characteristic of current stage of market development is more strict conditions in marketing sphere and promotion of drugs. DOI: http://dx.doi.org/10.12731/2218-7405-2013-12-2

A specific role of iron in promoting meristematic cell division during adventitious root formation.

Science.gov (United States)

Hilo, Alexander; Shahinnia, Fahimeh; Druege, Uwe; Franken, Philipp; Melzer, Michael; Rutten, Twan; von Wirén, Nicolaus; Hajirezaei, Mohammad-Reza

2017-07-10

Adventitious root (AR) formation is characterized by a sequence of physiological and morphological processes and determined by external factors, including mineral nutrition, the impacts of which remain largely elusive. Morphological and anatomical evaluation of the effects of mineral elements on AR formation in leafy cuttings of Petunia hybrida revealed a striking stimulation by iron (Fe) and a promotive action of ammonium (NH4+). The optimal application period for these nutrients corresponded to early division of meristematic cells in the rooting zone and coincided with increased transcript levels of mitotic cyclins. Fe-localization studies revealed an enhanced allocation of Fe to the nuclei of meristematic cells in AR initials. NH4+ supply promoted AR formation to a lesser extent, most likely by favoring the availability of Fe. We conclude that Fe acts locally by promoting cell division in the meristematic cells of AR primordia. These results highlight a specific biological function of Fe in AR development and point to an unexploited importance of Fe for the vegetative propagation of plants from cuttings. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Half a century of "the nuclear matrix".

Science.gov (United States)

Pederson, T

2000-03-01

A cell fraction that would today be termed "the nuclear matrix" was first described and patented in 1948 by Russian investigators. In 1974 this fraction was rediscovered and promoted as a fundamental organizing principle of eukaryotic gene expression. Yet, convincing evidence for this functional role of the nuclear matrix has been elusive and has recently been further challenged. What do we really know about the nonchromatin elements (if any) of internal nuclear structure? Are there objective reasons (as opposed to thinly veiled disdain) to question experiments that use harsh nuclear extraction steps and precipitation-prone conditions? Are the known biophysical properties of the nucleoplasm in vivo consistent with the existence of an extensive network of anastomosing filaments coursing dendritically throughout the interchromatin space? To what extent may the genome itself contribute information for its own quarternary structure in the interphase nucleus? These questions and recent work that bears on the mystique of the nuclear matrix are addressed in this essay. The degree to which gene expression literally depends on nonchromatin nuclear structure as a facilitating organizational format remains an intriguing but unsolved issue in eukaryotic cell biology, and considerable skepticism continues to surround the nuclear matrix fraction as an accurate representation of the in vivo situation.

Elastin-derived peptides promote abdominal aortic aneurysm formation by modulating M1/M2 macrophage polarization1

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Dale, Matthew A; Xiong, Wanfen; Carson, Jeffrey S; Suh, Melissa K; Karpisek, Andrew D.; Meisinger, Trevor M.; Casale, George P.; Baxter, B. Timothy

2016-01-01

Abdominal aortic aneurysm (AAA) is a dynamic vascular disease characterized by inflammatory cell invasion and extracellular matrix (ECM) degradation. Damage to elastin in the ECM results in release of elastin-derived peptides (EDPs), which are chemotactic for inflammatory cells such as monocytes. Their effect on macrophage polarization is less well known. Pro-inflammatory M1 macrophages initially are recruited to sites of injury but, if their effects are prolonged, they can lead to chronic inflammation that prevents normal tissue repair. Conversely, anti-inflammatory M2 macrophages reduce inflammation and aid in wound healing. Thus, a proper M1/M2 ratio is vital for tissue homeostasis. AAA tissue reveals a high M1/M2 ratio where pro-inflammatory cells and their associated markers dominate. In the present study, in vitro treatment of bone marrow-derived macrophages with EDPs induced M1 macrophage polarization. By using C57Bl/6 mice, antibody-mediated neutralization of EDPs reduced aortic dilation, matrix metalloproteinase activity, and pro-inflammatory cytokine expression at early and late time points after aneurysm induction. Furthermore, direct manipulation of the M1/M2 balance altered aortic dilation. Injection of M2 polarized macrophages reduced aortic dilation after aneurysm induction. EDPs promoted a pro-inflammatory environment in aortic tissue by inducing M1 polarization and neutralization of EDPs attenuated aortic dilation. The M1/M2 imbalance is vital to aneurysm formation. PMID:27183603

Bistability and Biofilm Formation in Bacillus subtilis

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Chai, Yunrong; Chu, Frances; Kolter, Roberto; Losick, Richard

2008-01-01

Summary Biofilms of Bacillus subtilis consist of long chains of cells that are held together in bundles by an extracellular matrix of exopolysaccharide and the protein TasA. The exopolysaccharide is produced by enzymes encoded by the epsA-O operon and the gene encoding TasA is located in the yqxM-sipW-tasA operon. Both operons are under the control of the repressor SinR. Derepression is mediated by the antirepressor SinI, which binds to SinR with a 1:1 stoichiometry. Paradoxically, in medium promoting derepression of the matrix operons, the overall concentration of SinR in the culture greatly exceeded that of SinI. We show that under biofilm-promoting conditions sinI, which is under the control of the response regulator Spo0A, was expressed only in a small subpopulation of cells, whereas sinR was expressed in almost all cells. Activation of Spo0A is known to be subject to a bistable switch, and we infer that SinI reaches levels sufficient to trigger matrix production only in the subpopulation of cells in which Spo0A is active. Additionally, evidence suggests that sinI is expressed at intermediate, but not low or high, levels of Spo0A activity, which may explain why certain nutritional conditions are more effective in promoting biofilm formation than others. PMID:18047568

Insulin-like growth factor I has independent effects on bone matrix formation and cell replication

International Nuclear Information System (INIS)

Hock, J.M.; Centrella, M.; Canalis, E.

1988-01-01

The effects of insulin-like growth factor-I (IGF-I) and insulin on bone matrix synthesis and bone cell replication were studied in cultured 21-day-old fetal rat calvariae. Histomorphometry techniques were developed to measure the incorporation of [2,3- 3 H]proline and [methyl- 3 H]thymidine into bone matrix and bone cell nuclei, respectively, using autoradiographs of sagittal sections of calvariae cultured with IGF-I, insulin, or vehicle for up to 96 h. To confirm an effect on bone formation, IGF-I was also studied for its effects on [ 3 H]proline incorporation into collagenase-digestible protein (CDP) and noncollagen protein and on [ 3 H]thymidine incorporation into acid-precipitable material (DNA). IGF-I at 10(-9)-10(-7) M significantly increased the rate of bone matrix apposition and CDP after 24 h by 45-50% and increased cell labeling by 8-fold in the osteoprogenitor cell zone, by 4-fold in the osteoblast cell zone, and by 2-fold in the periosteal fibroblast zone. Insulin at 10(-9)-10(-6) M also increased matrix apposition rate and CDP by 40-50%, but increased cell labeling by 2-fold only at a concentration of 10(-7) M or higher and then only in the osteoprogenitor cell zone. When hydroxyurea was added to IGF-I-treated bones, the effects of IGF-I on DNA synthesis were abolished, but the increase in bone matrix apposition induced by IGF-I was only partly diminished. In conclusion, IGF-I stimulates matrix synthesis in calvariae, an effect that is partly, although not completely, dependent on its stimulatory effect on DNA synthesis

CO_2 capture from flue gas using clathrate formation in the presence of thermodynamic promoters

International Nuclear Information System (INIS)

Kim, Soyoung; Choi, Sung-Deuk; Seo, Yongwon

2017-01-01

Tetrahydrofuran (THF) as a water-soluble sII clathrate former, cyclopentane (CP) as a water-insoluble sII clathrate former, and tetra n-butyl ammonium chloride (TBAC) as a water-soluble semiclathrate former were used to investigate their thermodynamic promotion effects on clathrate-based CO_2 capture from simulated flue gas. The phase equilibria of CO_2 (20%) + N_2 (80%) + promoter clathrates at different promoter concentrations revealed that the presence of THF, CP, and TBAC could significantly reduce the clathrate formation pressure. THF solutions provided the highest gas uptake and steepest CO_2 concentration changes in the vapor phase, whereas TBAC solutions showed the highest CO_2 selectivity (∼61%) in the clathrate phase. CP solutions exhibited a slower formation rate, but their final gas uptake and CO_2 selectivity in the clathrate phase were comparable to the THF solutions. Raman spectroscopy confirmed the enclathration of both CO_2 and N_2 in the clathrate cages and a structural transition due to the inclusion of promoters in the clathrate phase. The overall experimental results indicate that TBAC is a viable thermodynamic promoter for clathrate-based CO_2 capture from simulated flue gas, considering the lower pressure requirement for clathrate formation, higher CO_2 enrichment in the clathrate phase, non-toxicity, and non-volatility. - Highlights: • Clathrate-based CO_2 capture was investigated in the presence of thermodynamic promoters. • THF, CP, and TBAC demonstrated a significant thermodynamic promotion for CO_2 (20%) + N_2 (80%) clathrates. • The highest gas uptake was observed for the THF (5.6 mol%) solution. • TBAC solutions showed the highest CO_2 selectivity in the clathrate phase (∼61%). • Raman spectroscopy confirmed the guest gas enclathration and clathrate structure.

The effect of a collagen-elastin matrix on adhesion formation after flexor tendon repair in a rabbit model.

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Wichelhaus, Dagmar Alice; Beyersdoerfer, Sascha Tobias; Gierer, Philip; Vollmar, Brigitte; Mittlmeier, Th

2016-07-01

The outcome of flexor tendon surgery is negatively affected by the formation of adhesions which can occur during the healing of the tendon repair. In this experimental study, we sought to prevent adhesion formation by wrapping a collagen-elastin scaffold around the repaired tendon segment. In 28 rabbit hind legs, the flexor tendons of the third and fourth digits were cut and then repaired using a two-strand suture technique on the fourth digit and a four-strand technique on the third digit. Rabbits were randomly assigned to study and control groups. In the control group, the operation ended by closing the tendon sheath and the skin. In the study group, a collagen-elastin scaffold was wrapped around the repaired tendon segment in both digits. After 3 and 8 weeks, the tendons were harvested and processed histologically. The range of motion of the digits and the gap formation between the repaired tendon ends were measured. The formation of adhesions, infiltration of leucocytes and extracellular inflammatory response were quantified. At the time of tendon harvesting, all joints of the operated toes showed free range of motion. Four-strand core sutures lead to significantly less diastasis between the repaired tendon ends than two-strand core suture repairs. The collagen-elastin scaffold leads to greater gapping after 3 weeks compared to the controls treated without the matrix. Within the tendons treated with the collagen-elastin matrix, a significant boost of cellular and extracellular inflammation could be stated after 3 weeks which was reflected by a higher level of CAE positive cells and more formation of myofibroblasts in the αSMA stain in the study group. The inflammatory response subsided gradually and significantly until the late stage of the study. Both the cellular and extracellular inflammatory response was emphasized with the amount of material used for the repair. The use of a collagen-elastin matrix cannot be advised for the prevention of adhesion

Inflammation induced mTORC2-Akt-mTORC1 signaling promotes macrophage foam cell formation.

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Banerjee, Dipanjan; Sinha, Archana; Saikia, Sudeshna; Gogoi, Bhaskarjyoti; Rathore, Arvind K; Das, Anindhya Sundar; Pal, Durba; Buragohain, Alak K; Dasgupta, Suman

2018-06-05

The transformation of macrophages into lipid loaded foam cells is a critical and early event in the pathogenesis of atherosclerosis. Several recent reports highlighted that induction of TLR4 signaling promotes macrophage foam cell formation; however, the underlying molecular mechanisms have not been clearly elucidated. Here, we found that the TLR4 mediated inflammatory signaling communicated with mTORC2-Akt-mTORC1 metabolic cascade in macrophage and thereby promoting lipid uptake and foam cell formation. Mechanistically, LPS treatment markedly upregulates TLR4 mediated inflammatory pathway which by activating mTORC2 induces Akt phosphorylation at serine 473 and that aggravate mTORC1 dependent scavenger receptors expression and consequent lipid accumulation in THP-1 macrophages. Inhibition of mTORC2 either by silencing Rictor expression or inhibiting its association with mTOR notably prevents LPS induced Akt activation, scavenger receptors expression and macrophage lipid accumulation. Although suppression of mTORC1 expression by genetic knockdown of Raptor did not produce any significant change in Akt S473 phosphorylation, however, incubation with Akt activator in Rictor silenced cells failed to promote scavenger receptors expression and macrophage foam cell formation. Thus, present research explored the signaling pathway involved in inflammation induced macrophage foam cells formation and therefore, targeting this pathway might be useful for preventing macrophage foam cell formation. Copyright © 2018 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

The combined effect of thermodynamic promoters tetrahydrofuran and cyclopentane on the kinetics of flue gas hydrate formation

DEFF Research Database (Denmark)

Daraboina, Nagu; von Solms, Nicolas

2015-01-01

) hydrate formation using a rocking cell apparatus. Hydrate formation and decomposition kinetics were investigated by constant cooling (hydrate nucleation temperature) and isothermal (hydrate nucleation time) methods. Improved (synergistic) hydrate formation kinetics (hydrate nucleation and growth) were...... of these two promoters is favorable both thermodynamically and kinetically for hydrate formation from flue gas....

Peeping into human renal calcium oxalate stone matrix: characterization of novel proteins involved in the intricate mechanism of urolithiasis.

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Kanu Priya Aggarwal

Full Text Available BACKGROUND: The increasing number of patients suffering from urolithiasis represents one of the major challenges which nephrologists face worldwide today. For enhancing therapeutic outcomes of this disease, the pathogenic basis for the formation of renal stones is the need of hour. Proteins are found as major component in human renal stone matrix and are considered to have a potential role in crystal-membrane interaction, crystal growth and stone formation but their role in urolithiasis still remains obscure. METHODS: Proteins were isolated from the matrix of human CaOx containing kidney stones. Proteins having MW>3 kDa were subjected to anion exchange chromatography followed by molecular-sieve chromatography. The effect of these purified proteins was tested against CaOx nucleation and growth and on oxalate injured Madin-Darby Canine Kidney (MDCK renal epithelial cells for their activity. Proteins were identified by Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF MS followed by database search with MASCOT server. In silico molecular interaction studies with CaOx crystals were also investigated. RESULTS: Five proteins were identified from the matrix of calcium oxalate kidney stones by MALDI-TOF MS followed by database search with MASCOT server with the competence to control the stone formation process. Out of which two proteins were promoters, two were inhibitors and one protein had a dual activity of both inhibition and promotion towards CaOx nucleation and growth. Further molecular modelling calculations revealed the mode of interaction of these proteins with CaOx at the molecular level. CONCLUSIONS: We identified and characterized Ethanolamine-phosphate cytidylyltransferase, Ras GTPase-activating-like protein, UDP-glucose:glycoprotein glucosyltransferase 2, RIMS-binding protein 3A, Macrophage-capping protein as novel proteins from the matrix of human calcium oxalate stone which play a critical role in kidney stone

Promotion of Tumor Invasion by Cooperation of Granulocytes and Macrophages Activated by Anti-tumor Antibodies

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Emilio Barbera-Guillem

1999-11-01

Full Text Available We investigated the potential role of anti-tumor antibodies and tumor antigens in the formation of immune complexes which promote matrix degradation and angiogenesis. B-cell deficient or B-cell depleted mice showed a reduction in tumor invasion and metastasis. In vitro invasion assays and in vivo models of metastasis showed that anti-sTn antibodies and sTn tumor antigens form complexes which induce granulocytes and macrophages together to mediate tumor invasion and metastasis by processes including extracellular matrix degradation and angiogenesis. These results suggest the existence of a tumor promoting role of a B-cell immune response induced by shed tumor associated antigens of solid, nonlymphoid tumors.

Mechanical Loading Improves Tendon-Bone Healing in a Rabbit Anterior Cruciate Ligament Reconstruction Model by Promoting Proliferation and Matrix Formation of Mesenchymal Stem Cells and Tendon Cells

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Fanglong Song

2017-02-01

Full Text Available Background/Aims: This study investigated the effect of mechanical stress on tendon-bone healing in a rabbit anterior cruciate ligament (ACL reconstruction model as well as cell proliferation and matrix formation in co-culture of bone-marrow mesenchymal stem cells (BMSCs and tendon cells (TCs. Methods: The effect of continuous passive motion (CPM therapy on tendon-bone healing in a rabbit ACL reconstruction model was evaluated by histological analysis, biomechanical testing and gene expressions at the tendon-bone interface. Furthermore, the effect of mechanical stretch on cell proliferation and matrix synthesis in BMSC/TC co-culture was also examined. Results: Postoperative CPM therapy significantly enhanced tendon-bone healing, as evidenced by increased amount of fibrocartilage, elevated ultimate load to failure levels, and up-regulated gene expressions of Collagen I, alkaline phosphatase, osteopontin, Tenascin C and tenomodulin at the tendon-bone junction. In addition, BMSC/TC co-culture treated with mechanical stretch showed a higher rate of cell proliferation and enhanced expressions of Collagen I, Collagen III, alkaline phosphatase, osteopontin, Tenascin C and tenomodulin than that of controls. Conclusion: These results demonstrated that proliferation and differentiation of local precursor cells could be enhanced by mechanical stimulation, which results in enhanced regenerative potential of BMSCs and TCs in tendon-bone healing.

Pseudomonas biofilm matrix composition and niche biology

Science.gov (United States)

Mann, Ethan E.; Wozniak, Daniel J.

2014-01-01

Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Critical for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Additionally, other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix molecules, including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphology. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, respectively, and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review will focus on various polysaccharides as well as additional Pseudomonas biofilm matrix components. Discussions will center on structure–function relationships, regulation, and the role of individual matrix molecules in niche biology. PMID:22212072

Three-Dimensional-Bioprinted Dopamine-Based Matrix for Promoting Neural Regeneration.

Science.gov (United States)

Zhou, Xuan; Cui, Haitao; Nowicki, Margaret; Miao, Shida; Lee, Se-Jun; Masood, Fahed; Harris, Brent T; Zhang, Lijie Grace

2018-03-14

Central nerve repair and regeneration remain challenging problems worldwide, largely because of the extremely weak inherent regenerative capacity and accompanying fibrosis of native nerves. Inadequate solutions to the unmet needs for clinical therapeutics encourage the development of novel strategies to promote nerve regeneration. Recently, 3D bioprinting techniques, as one of a set of valuable tissue engineering technologies, have shown great promise toward fabricating complex and customizable artificial tissue scaffolds. Gelatin methacrylate (GelMA) possesses excellent biocompatible and biodegradable properties because it contains many arginine-glycine-aspartic acids (RGD) and matrix metalloproteinase sequences. Dopamine (DA), as an essential neurotransmitter, has proven effective in regulating neuronal development and enhancing neurite outgrowth. In this study, GelMA-DA neural scaffolds with hierarchical structures were 3D-fabricated using our custom-designed stereolithography-based printer. DA was functionalized on GelMA to synthesize a biocompatible printable ink (GelMA-DA) for improving neural differentiation. Additionally, neural stem cells (NSCs) were employed as the primary cell source for these scaffolds because of their ability to terminally differentiate into a variety of cell types including neurons, astrocytes, and oligodendrocytes. The resultant GelMA-DA scaffolds exhibited a highly porous and interconnected 3D environment, which is favorable for supporting NSC growth. Confocal microscopy analysis of neural differentiation demonstrated that a distinct neural network was formed on the GelMA-DA scaffolds. In particular, the most significant improvements were the enhanced neuron gene expression of TUJ1 and MAP2. Overall, our results demonstrated that 3D-printed customizable GelMA-DA scaffolds have a positive role in promoting neural differentiation, which is promising for advancing nerve repair and regeneration in the future.

MMP-sensitive PEG diacrylate hydrogels with spatial variations in matrix properties stimulate directional vascular sprout formation.

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Michael V Turturro

Full Text Available The spatial presentation of immobilized extracellular matrix (ECM cues and matrix mechanical properties play an important role in directed and guided cell behavior and neovascularization. The goal of this work was to explore whether gradients of elastic modulus, immobilized matrix metalloproteinase (MMP-sensitivity, and YRGDS cell adhesion ligands are capable of directing 3D vascular sprout formation in tissue engineered scaffolds. PEGDA hydrogels were engineered with mechanical and biofunctional gradients using perfusion-based frontal photopolymerization (PBFP. Bulk photopolymerized hydrogels with uniform mechanical properties, degradation, and immobilized biofunctionality served as controls. Gradient hydrogels exhibited an 80.4% decrease in elastic modulus and a 56.2% decrease in immobilized YRGDS. PBFP hydrogels also demonstrated gradients in hydrogel degradation with degradation times ranging from 10-12 hours in the more crosslinked regions to 4-6 hours in less crosslinked regions. An in vitro model of neovascularization, composed of co-culture aggregates of endothelial and smooth muscle cells, was used to evaluate the effect of these gradients on vascular sprout formation. Aggregate invasion in gradient hydrogels occurred bi-directionally with sprout alignment observed in the direction parallel to the gradient while control hydrogels with homogeneous properties resulted in uniform invasion. In PBFP gradient hydrogels, aggregate sprout length was found to be twice as long in the direction parallel to the gradient as compared to the perpendicular direction after three weeks in culture. This directionality was found to be more prominent in gradient regions of increased stiffness, crosslinked MMP-sensitive peptide presentation, and immobilized YRGDS concentration.

In-situ formation of nanoparticles within a silicon-based matrix

Science.gov (United States)

Thoma, Steven G [Albuquerque, NM; Wilcoxon, Jess P [Albuquerque, NM; Abrams, Billie L [Albuquerque, NM

2008-06-10

A method for encapsulating nanoparticles with an encapsulating matrix that minimizes aggregation and maintains favorable properties of the nanoparticles. The matrix comprises silicon-based network-forming compounds such as ormosils and polysiloxanes. The nanoparticles are synthesized from precursors directly within the silicon-based matrix.

Assembly and development of the Pseudomonas aeruginosa biofilm matrix.

Directory of Open Access Journals (Sweden)

Luyan Ma

2009-03-01

Full Text Available Virtually all cells living in multicellular structures such as tissues and organs are encased in an extracellular matrix. One of the most important features of a biofilm is the extracellular polymeric substance that functions as a matrix, holding bacterial cells together. Yet very little is known about how the matrix forms or how matrix components encase bacteria during biofilm development. Pseudomonas aeruginosa forms environmentally and clinically relevant biofilms and is a paradigm organism for the study of biofilms. The extracellular polymeric substance of P. aeruginosa biofilms is an ill-defined mix of polysaccharides, nucleic acids, and proteins. Here, we directly visualize the product of the polysaccharide synthesis locus (Psl exopolysaccharide at different stages of biofilm development. During attachment, Psl is anchored on the cell surface in a helical pattern. This promotes cell-cell interactions and assembly of a matrix, which holds bacteria in the biofilm and on the surface. Chemical dissociation of Psl from the bacterial surface disrupted the Psl matrix as well as the biofilm structure. During biofilm maturation, Psl accumulates on the periphery of 3-D-structured microcolonies, resulting in a Psl matrix-free cavity in the microcolony center. At the dispersion stage, swimming cells appear in this matrix cavity. Dead cells and extracellular DNA (eDNA are also concentrated in the Psl matrix-free area. Deletion of genes that control cell death and autolysis affects the formation of the matrix cavity and microcolony dispersion. These data provide a mechanism for how P. aeruginosa builds a matrix and subsequently a cavity to free a portion of cells for seeding dispersal. Direct visualization reveals that Psl is a key scaffolding matrix component and opens up avenues for therapeutics of biofilm-related complications.

Mixed Fibronectin-Derived Peptides Conjugated to a Chitosan Matrix Effectively Promotes Biological Activities through Integrins, α4β1, α5β1, αvβ3, and Syndecan

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Hozumi Kentaro

2016-11-01

Full Text Available Mimicking the biological function of the extracellular matrix is an approach to developing cell adhesive biomaterials. The RGD peptide, derived from fibronectin (Fn, mainly binds to integrin αvβ3 and has been widely used as a cell adhesive peptide on various biomaterials. However, cell adhesion to Fn is thought to be mediated by several integrin subtypes and syndecans. In this study, we synthesized an RGD-containing peptide (FIB1 and four integrin α4β1-binding-related motif-containing peptides (LDV, IDAPS, KLDAPT, and PRARI and constructed peptide-chitosan matrices. The FIB1-chitosan matrix promoted human dermal fibroblast (HDF attachment, and the C-terminal elongated PRARI (ePRARI-C-conjugated chitosan matrix significantly promoted HDF attachment through integrin α4β1 and syndecan binding. Next, we constructed a mixed ePRARI-C- and FIB1-chitosan matrix to develop a Fn mimetic biomaterial. The mixed ePRARI-C/FIB1-chitosan matrix promoted significantly better cell attachment and neurite outgrowth compared to those of either ePRARI-C- or FIB1-chitosan matrices. HDF adhesion to the ePRARI-C/FIB1-chitosan matrix was mediated by integrin, α4β1, α5β1, and αvβ3, similar to HDF adhesion to Fn. These data suggest that an ePRARI-C/FIB1-chitosan matrix can be used as a tool to analyze the multiple functions of Fn and can serve as a Fn-mimetic biomaterial.

Prophage spontaneous activation promotes DNA release enhancing biofilm formation in Streptococcus pneumoniae.

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Margarida Carrolo

Full Text Available Streptococcus pneumoniae (pneumococcus is able to form biofilms in vivo and previous studies propose that pneumococcal biofilms play a relevant role both in colonization and infection. Additionally, pneumococci recovered from human infections are characterized by a high prevalence of lysogenic bacteriophages (phages residing quiescently in their host chromosome. We investigated a possible link between lysogeny and biofilm formation. Considering that extracellular DNA (eDNA is a key factor in the biofilm matrix, we reasoned that prophage spontaneous activation with the consequent bacterial host lysis could provide a source of eDNA, enhancing pneumococcal biofilm development. Monitoring biofilm growth of lysogenic and non-lysogenic pneumococcal strains indicated that phage-infected bacteria are more proficient at forming biofilms, that is their biofilms are characterized by a higher biomass and cell viability. The presence of phage particles throughout the lysogenic strains biofilm development implicated prophage spontaneous induction in this effect. Analysis of lysogens deficient for phage lysin and the bacterial major autolysin revealed that the absence of either lytic activity impaired biofilm development and the addition of DNA restored the ability of mutant strains to form robust biofilms. These findings establish that limited phage-mediated host lysis of a fraction of the bacterial population, due to spontaneous phage induction, constitutes an important source of eDNA for the S. pneumoniae biofilm matrix and that this localized release of eDNA favors biofilm formation by the remaining bacterial population.

Facultative control of matrix production optimizes competitive fitness in Pseudomonas aeruginosa PA14 biofilm models.

Science.gov (United States)

Madsen, Jonas S; Lin, Yu-Cheng; Squyres, Georgia R; Price-Whelan, Alexa; de Santiago Torio, Ana; Song, Angela; Cornell, William C; Sørensen, Søren J; Xavier, Joao B; Dietrich, Lars E P

2015-12-01

As biofilms grow, resident cells inevitably face the challenge of resource limitation. In the opportunistic pathogen Pseudomonas aeruginosa PA14, electron acceptor availability affects matrix production and, as a result, biofilm morphogenesis. The secreted matrix polysaccharide Pel is required for pellicle formation and for colony wrinkling, two activities that promote access to O2. We examined the exploitability and evolvability of Pel production at the air-liquid interface (during pellicle formation) and on solid surfaces (during colony formation). Although Pel contributes to the developmental response to electron acceptor limitation in both biofilm formation regimes, we found variation in the exploitability of its production and necessity for competitive fitness between the two systems. The wild type showed a competitive advantage against a non-Pel-producing mutant in pellicles but no advantage in colonies. Adaptation to the pellicle environment selected for mutants with a competitive advantage against the wild type in pellicles but also caused a severe disadvantage in colonies, even in wrinkled colony centers. Evolution in the colony center produced divergent phenotypes, while adaptation to the colony edge produced mutants with clear competitive advantages against the wild type in this O2-replete niche. In general, the structurally heterogeneous colony environment promoted more diversification than the more homogeneous pellicle. These results suggest that the role of Pel in community structure formation in response to electron acceptor limitation is unique to specific biofilm models and that the facultative control of Pel production is required for PA14 to maintain optimum benefit in different types of communities. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Marginal zinc deficiency in pregnant rats impairs bone matrix formation and bone mineralization in their neonates.

Science.gov (United States)

Nagata, Masashi; Kayanoma, Megumu; Takahashi, Takeshi; Kaneko, Tetsuo; Hara, Hiroshi

2011-08-01

Zinc (Zn) deficiency during pregnancy may result in a variety of defects in the offspring. We evaluated the influence of marginal Zn deficiency during pregnancy on neonatal bone status. Nine-week-old male Sprague-Dawley rats were divided into two groups and fed AIN-93G-based experimental diets containing 35 mg Zn/kg (Zn adequately supplied, N) or 7 mg Zn/kg (low level of Zn, L) from 14-day preconception to 20 days of gestation, that is, 1 day before normal delivery. Neonates were delivered by cesarean section. Litter size and neonate weight were not different between the two groups. However, in the L-diet-fed dam group, bone matrix formation in isolated neonatal calvaria culture was clearly impaired and was not recovered by the addition of Zn into the culture media. Additionally, serum concentration of osteocalcin, as a bone formation parameter, was lower in neonates from the L-diet-fed dam group. Impaired bone mineralization was observed with a significantly lower content of phosphorus in neonate femurs from L-diet-fed dams compared with those from N-diet-fed dams. Moreover, Zn content in the femur and calvaria of neonates from the L-diet group was lower than that of the N-diet-fed group. In the marginally Zn-deficient dams, femoral Zn content, serum concentrations of Zn, and osteocalcin were reduced when compared with control dams. We conclude that maternal Zn deficiency causes impairment of bone matrix formation and bone mineralization in neonates, implying the importance of Zn intake during pregnancy for proper bone development of offspring.

Formation Mechanism of Self Assembled Horizontal ErSb Nanowires Embedded in a GaSb(001) Matrix

Science.gov (United States)

Wilson, Nathaniel; Kraemer, Stephan; PalmstrøM, Chris

The ErxGa1-xSb exhibits a variety of self-assembling nanostructures. In order to harness these nanostructures for use in devices and other material systems it is important to understand their formation. We have characterized the growth mechanism of self-assembled horizontal ErSb nanowires in a GaSb(001) matrix through the use of in-situ Scanning Tunneling Microscopy (STM) as well as ex-situ Transmission Electron Microscopy (TEM). We observe large GaSb macrosteps on the growth surface of Er.3Ga.7Sb samples. The areas near the ledge and base of the macrosteps show significant differences in size and distribution of ErSb nanowires. Results suggest that the formation of macrosteps drives the transition from vertical to horizontal nanowires in the ErxGa1-xSb system. We also observe a low temperature growth mode, which results in horizontal nanowire formation under a wide range of flux conditions. This new growth mode does not exhibit the embedded growth observed in the formation of nanowires at higher temperatures and may allow for horizontal nanowire formation without the presence of macrosteps, as well as the formation of smaller nanoparticles which may be useful for achieving smaller nanoparticle dimensions and electron confinement effects. This work was supported by NSF-DMR under 1507875.

A failure of matrix metalloproteinase inhibition in the prevention of rat intracranial aneurysm formation

International Nuclear Information System (INIS)

Kaufmann, T.J.; Kallmes, D.F.; Marx, W.F.

2006-01-01

We tested the hypothesis that nonspecific matrix metalloproteinase (MMP) inhibition with doxycycline would decrease the incidence of intracranial aneurysm formation in a rat aneurysm model. We performed common carotid artery ligation on 96 Long-Evans rats. A treatment group of 48 animals was chosen at random to receive oral doxycycline (3 mg/kg) in addition to standard rat chow, and the control group of 48 animals received standard rat chow only. The major circle of Willis arteries was dissected at 1 year following carotid ligation, and the proportions of animals with aneurysms were compared between groups using Fisher's exact test. Four animals given oral doxycycline and ten control animals expired before 1 year. Of the examined animals, eight saccular intracranial aneurysms were found in 8 of 45 animals which had received doxycycline (17.8%) and seven saccular intracranial aneurysms were found in 7 of 37 control animals (18.9%). There was no significant difference in aneurysm formation between the doxycycline-treated and control groups (P=0.894). Nonspecific MMP inhibition with doxycycline is not effective in preventing intracranial aneurysm formation in a rat model. (orig.)

Functional role of EMMPRIN in the formation and mineralisation of dental matrix in mouse molars.

Science.gov (United States)

Xie, Ming; Xing, Guofang; Hou, Liwen; Bao, Jing; Chen, Yuqing; Jiao, Ting; Zhang, Fuqiang

2015-02-01

Our previous research has shown that the extracellular matrix metalloproteinase inducer (EMMPRIN) is expressed during and may function in the early development of tooth germs. In the present study, we observed the specific expression of EMMPRIN in ameloblasts and odontoblasts during the middle and late stages of tooth germ development using immunohistochemistry. Furthermore, to extend our understanding of the function of EMMPRIN in odontogenesis, we used an anti-EMMPRIN function-blocking antibody to remove EMMPRIN activity in tooth germ culture in vitro. Both the formation and mineralisation of dental hard tissues were suppressed in the tooth germ culture after the abrogation of EMMPRIN. Meanwhile, significant reductions in VEGF, MMP-9, ALPL, ameloblastin, amelogenin and enamelin expression were observed in antibody-treated tooth germ explants compared to control and normal serum-treated explants. The current results illustrate that EMMPRIN may play a critical role in the processing and maturation of the dental matrix.

Study on the Promotion Effect of Ionic Liquid on CH4 Hydrate Formation

International Nuclear Information System (INIS)

Shin, Ju-Young; Mun, Sungyong; Kang, Seong-Pil; Kim, Kisub

2013-01-01

In this study, we investigated the kinetics of gas hydrate formation in the presence of ionic liquid (IL). Hydroxyethyl-methyl-morpholinium chloride (HEMM-Cl) was chosen as a material for the promotion effect test. Phase equilibrium curve for CH 4 hydrate with aqueous IL solution was obtained and its induction time and consumed amount of CH 4 gas were also measured. Aqueous solutions containing 20-20,000 ppm of HEMM-Cl was prepared and studied at 70 bar and 274.15 K. To compare the measured results to those of the conventional promoter, sodium dodecyl sulfate was also tested at the same condition. Result showed that the hydrate equilibrium curve was shifted toward higher pressure and lower temperature region. In addition, the induction time on CH 4 hydrate formation in the presence of IL was not shown. The amount of consumed CH 4 was increased with the whole range of tested concentration of IL and the highest consumption of CH 4 happened at 1,000 ppm of HEMM-Cl. HEMM-Cl induced and enhanced the CH 4 hydrate formation with a small amount of addition. Obtained result is expected to be applied for the development of technologies such as gas storage and transport using gas hydrates

Association of matrix metalloproteinase-2 gene promoter ...

Indian Academy of Sciences (India)

coronary heart disease. Atherosclerosis of the coronary ar- teries is the predominant AMI mechanism. Atherosclerotic plaque growth occurs through structural changes which al- low the accumulation of cells, extracellular matrix and lipids in the intimate layer of the diseased artery. The rupture or erosion of the fibrous layer of ...

Study on invadopodia formation for lung carcinoma invasion with a microfluidic 3D culture device.

Science.gov (United States)

Wang, Shanshan; Li, Encheng; Gao, Yanghui; Wang, Yan; Guo, Zhe; He, Jiarui; Zhang, Jianing; Gao, Zhancheng; Wang, Qi

2013-01-01

Invadopodia or invasive feet, which are actin-rich membrane protrusions with matrix degradation activity formed by invasive cancer cells, are a key determinant in the malignant invasive progression of tumors and represent an important target for cancer therapies. In this work, we presented a microfluidic 3D culture device with continuous supplement of fresh media via a syringe pump. The device mimicked tumor microenvironment in vivo and could be used to assay invadopodia formation and to study the mechanism of human lung cancer invasion. With this device, we investigated the effects of epidermal growth factor (EGF) and matrix metalloproteinase (MMP) inhibitor, GM6001 on invadopodia formation by human non-small cell lung cancer cell line A549 in 3D matrix model. This device was composed of three units that were capable of achieving the assays on one control group and two experimental groups' cells, which were simultaneously pretreated with EGF or GM6001 in parallel. Immunofluorescence analysis of invadopodia formation and extracellular matrix degradation was conducted using confocal imaging system. We observed that EGF promoted invadopodia formation by A549 cells in 3D matrix and that GM6001 inhibited the process. These results demonstrated that epidermal growth factor receptor (EGFR) signaling played a significant role in invadopodia formation and related ECM degradation activity. Meanwhile, it was suggested that MMP inhibitor (GM6001) might be a powerful therapeutic agent targeting invadopodia formation in tumor invasion. This work clearly demonstrated that the microfluidic-based 3D culture device provided an applicable platform for elucidating the mechanism of cancer invasion and could be used in testing other anti-invasion agents.

Host-race formation: promoted by phenology, constrained by heritability.

Science.gov (United States)

Whipple, A V; Abrahamson, W G; Khamiss, M A; Heinrich, P L; Urian, A G; Northridge, E M

2009-04-01

Host-race formation is promoted by genetic trade-offs in the ability of herbivores to use alternate hosts, including trade-offs due to differential timing of host-plant availability. We examined the role of phenology in limiting host-plant use in the goldenrod gall fly (Eurosta solidaginis) by determining: (1) whether phenology limits alternate host use, leading to a trade-off that could cause divergent selection on Eurosta emergence time and (2) whether Eurosta has the genetic capacity to respond to such selection in the face of existing environmental variation. Experiments demonstrated that oviposition and gall induction on the alternate host, Solidago canadensis, were the highest on young plants, whereas the highest levels of gall induction on the normal host, Solidago gigantea, occurred on intermediate-age plants. These findings indicate a phenological trade-off for host-plant use that sets up the possibility of divergent selection on emergence time. Heritability, estimated by parent-offspring regression, indicated that host-race formation is impeded by the amount of genetic variation, relative to environmental, for emergence time.

The Biological Observation Matrix (BIOM) format or: how I learned to stop worrying and love the ome-ome.

Science.gov (United States)

McDonald, Daniel; Clemente, Jose C; Kuczynski, Justin; Rideout, Jai Ram; Stombaugh, Jesse; Wendel, Doug; Wilke, Andreas; Huse, Susan; Hufnagle, John; Meyer, Folker; Knight, Rob; Caporaso, J Gregory

2012-07-12

We present the Biological Observation Matrix (BIOM, pronounced "biome") format: a JSON-based file format for representing arbitrary observation by sample contingency tables with associated sample and observation metadata. As the number of categories of comparative omics data types (collectively, the "ome-ome") grows rapidly, a general format to represent and archive this data will facilitate the interoperability of existing bioinformatics tools and future meta-analyses. The BIOM file format is supported by an independent open-source software project (the biom-format project), which initially contains Python objects that support the use and manipulation of BIOM data in Python programs, and is intended to be an open development effort where developers can submit implementations of these objects in other programming languages. The BIOM file format and the biom-format project are steps toward reducing the "bioinformatics bottleneck" that is currently being experienced in diverse areas of biological sciences, and will help us move toward the next phase of comparative omics where basic science is translated into clinical and environmental applications. The BIOM file format is currently recognized as an Earth Microbiome Project Standard, and as a Candidate Standard by the Genomic Standards Consortium.

Nanocomposites with thermosetting matrix: structure formation at the interphase boundary

Directory of Open Access Journals (Sweden)

KOROLEV Evgenij Valerjevich

2014-06-01

Full Text Available Composites with thermosetting matrix are often characterized by elevated values of operational properties – flexural and compressive strength, resistance to aggressive environments, etc. At the same time the cost of most thermosets (particularly – epoxy resins is quite high. Because of this the area of application of polymer composites in construction is limited. One of such application is the creation of multifunctional coatings. The high cost of resin dictates the need to improve the operational properties to ensure economic efficiency. So far, the known way to improve the operational properties is to produce nanoscale interfacial layer between fine filler and matrix in block. This way proved to be effective, but mechanism of the improvement is still uncertain. There areat least two different theories – so-called «adhesion theory» and «theory of deformable layer». The investigation is complicated by the variety of oligomers, hardeners (crosslinking agents and precursors of nanomodifiers. It is becoming more common lately to use adducts of aliphatic amines and epoxy oligomers as hardeners. As precursors of nanomodifiers the organosilicon compounds with siloxane bond in the main chain can be successfully used. In this paper we present results of investigation of a model system comprised of oligomer, crosslinking agent and precursor. The analysis of structure is carried out by means of Raman spectroscopy and atomic force microscopy. It is shown that at gelation point modifier has no significant effect on the chemical composition of the curing products; nevertheless, the admixture of modifier reduces the regularity of the emerging three-dimensional spatial net of thermoset. After completion of curing process the irregular spatial grid is still present. This indicates that in composites admixture of organosilicon precursors may lead to the formation of transition layer with reduced modulus of elasticity. Such layer, in turn, causes stress

Mini-lecture course: Introduction into hierarchical matrix technique

KAUST Repository

Litvinenko, Alexander

2017-12-14

The H-matrix format has a log-linear computational cost and storage O(kn log n), where the rank k is a small integer and n is the number of locations (mesh points). The H-matrix technique allows us to work with general class of matrices (not only structured or Toeplits or sparse). H-matrices can keep the H-matrix data format during linear algebra operations (inverse, update, Schur complement).

Response of induced bone defects in horses to collagen matrix containing the human parathyroid hormone gene.

Science.gov (United States)

Backstrom, Kristin C; Bertone, Alicia L; Wisner, Erik R; Weisbrode, Stephen E

2004-09-01

To determine whether human parathyroid hormone (hPTH) gene in collagen matrix could safely promote bone formation in diaphyseal or subchondral bones of horses. 8 clinically normal adult horses. Amount, rate, and quality of bone healing for 13 weeks were determined by use of radiography, quantitative computed tomography, and histomorphometric analysis. Diaphyseal cortex and subchondral bone defects of metacarpi were filled with hPTH(1-34) gene-activated matrix (GAM) or remained untreated. Joints were assessed on the basis of circumference, synovial fluid analysis, pain on flexion, lameness, and gross and histologic examination. Bone volume index was greater for cortical defects treated with hPTH(1-34) GAM, compared with untreated defects. Bone production in cortical defects treated with hPTH(1-34) GAM positively correlated with native bone formation in untreated defects. In contrast, less bone was detected in hPTH(1-34) GAM-treated subchondral bone defects, compared with untreated defects, and histology confirmed poorer healing and residual collagen sponge. Use of hPTH(1-34) GAM induced greater total bone, specifically periosteal bone, after 13 weeks of healing in cortical defects of horses. The hPTH(1-34) GAM impeded healing of subchondral bone but was biocompatible with joint tissues. Promotion of periosteal bone formation may be beneficial for healing of cortical fractures in horses, but the delay in onset of bone formation may negate benefits. The hPTH(1-34) GAM used in this study should not be placed in articular subchondral bone defects, but contact with articular surfaces is unlikely to cause short-term adverse effects.

A survey of matrix theory and matrix inequalities

CERN Document Server

Marcus, Marvin

2010-01-01

Written for advanced undergraduate students, this highly regarded book presents an enormous amount of information in a concise and accessible format. Beginning with the assumption that the reader has never seen a matrix before, the authors go on to provide a survey of a substantial part of the field, including many areas of modern research interest.Part One of the book covers not only the standard ideas of matrix theory, but ones, as the authors state, ""that reflect our own prejudices,"" among them Kronecker products, compound and induced matrices, quadratic relations, permanents, incidence

Matrix- and plasma-derived peptides promote tissue-specific injury responses and wound healing in diabetic swine.

Science.gov (United States)

Sheets, Anthony R; Massey, Conner J; Cronk, Stephen M; Iafrati, Mark D; Herman, Ira M

2016-07-02

Non-healing wounds are a major global health concern and account for the majority of non-traumatic limb amputations worldwide. However, compared to standard care practices, few advanced therapeutics effectively resolve these injuries stemming from cardiovascular disease, aging, and diabetes-related vasculopathies. While matrix turnover is disrupted in these injuries, debriding enzymes may promote healing by releasing matrix fragments that induce cell migration, proliferation, and morphogenesis, and plasma products may also stimulate these processes. Thus, we created matrix- and plasma-derived peptides, Comb1 and UN3, which induce cellular injury responses in vitro, and accelerate healing in rodent models of non-healing wounds. However, the effects of these peptides in non-healing wounds in diabetes are not known. Here, we interrogated whether these peptides stimulate healing in a diabetic porcine model highly reminiscent of human healing impairments in type 1 and type 2-diabetes. After 3-6 weeks of streptozotocin-induced diabetes, full-thickness wounds were surgically created on the backs of adult female Yorkshire swine under general anesthesia. Comb1 and UN3 peptides or sterile saline (negative control) were administered to wounds daily for 3-7 days. Following sacrifice, wound tissues were harvested, and quantitative histological and immunohistochemical analyses were performed for wound closure, angiogenesis and granulation tissue deposition, along with quantitative molecular analyses of factors critical for angiogenesis, epithelialization, and dermal matrix remodeling. Comb1 and UN3 significantly increase re-epithelialization and angiogenesis in diabetic porcine wounds, compared to saline-treated controls. Additionally, fluorescein-conjugated Comb1 labels keratinocytes, fibroblasts, and vascular endothelial cells in porcine wounds, and Far western blotting reveals these cell populations express multiple fluorescein-Comb1-interacting proteins in vitro. Further

Matrix Information Geometry

CERN Document Server

Bhatia, Rajendra

2013-01-01

This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR).  During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented  are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.  

Aging promotes todorokite formation from layered manganese oxide at near-surface conditions

Energy Technology Data Exchange (ETDEWEB)

Cui, Haojie [Chinese Academy of Sciences, Xiamen (China). Key Lab. of Urban Environment and Health; Huazhong Agricultural Univ., Ministry of Agriculture, Wuhan (China). Key Lab. of Subtropical Agricultural Resources and Environment; Liu, Fan; Feng, Xionghan; Tan, Wenfeng [Huazhong Agricultural Univ., Ministry of Agriculture, Wuhan (China). Key Lab. of Subtropical Agricultural Resources and Environment; Wang, Ming Kuang [National Taiwan Univ., Taipei (China). Dept. of Agricultural Chemistry

2010-12-15

Todorokite is one common manganese oxide in soils and sediments and is commonly formed from layered Na-buserite. Aging processes can alter the physicochemical properties of freshly formed Na-buserite in natural environments. However, it is not clear whether and how aging affects the formation of todorokites. In the present paper, Na-buserite with aging treatment was employed to prepare todorokite at atmospheric pressure to investigate the effects of aging treatment of Na-buserite on the formation of todorokite. Four aged Na-buserite samples, which are produced through oxidation of Mn{sup 2+} in concentrated NaOH medium by O{sub 2} with aging for 3, 6, 9, and 12 months, were employed to investigate the effects of aging processes on the transformation from Na-buserite to todorokite by Mg{sup 2+}-templating reaction at atmospheric pressure. The manganese oxides were examined using X-ray diffraction (XRD), elemental analysis, determinations of the average manganese oxidation number, infrared spectroscopy (IR), and transmission electron microscopy (TEM). The XRD, IR, and elemental analyses indicate that aging treatment can alter the substructure of the freshly synthesized Na-buserite. During the aging process, some of the Mn(III) may migrate into the interlayer region or disproportionate to form Mn{sup 2+} and Mn{sup 4+} from the layer of Na-buserite and the concomitant formation of layer vacancies. The interlayer Mn{sup 3+} or Mn{sup 2+} occupied above or below the layer vacancy sites and become corner-sharing octahedral. XRD analyses and TEM clearly show that the transformation from Na-buserite to todorokite was promoted by aging treatments. The alterations of substructure of aged Na-buserites can promote the rearrangement of manganese to construct a tunnel structure during the transformation from layered manganese oxides to tunnel-structure todorokite at atmospheric pressure. The transformation from Na-buserite to todorokite was promoted by aging treatments at

Effect of enamel matrix derivative and parathyroid hormone on bone formation in standardized osseous defects: an experimental study in minipigs

DEFF Research Database (Denmark)

Jensen, Simon S; Chen, B; Bornstein, Michael M

2011-01-01

Previous experimental studies have indicated that locally administered enamel matrix derivative (EMD) and parathyroid hormone (PTH) may have a stimulatory effect on bone formation. However, it is not clear if the positive effect of EMD is related to its effect on the periodontium as a whole...

Increased extracellular matrix density decreases MCF10A breast cell acinus formation in 3D culture conditions.

Science.gov (United States)

Lance, Amanda; Yang, Chih-Chao; Swamydas, Muthulekha; Dean, Delphine; Deitch, Sandy; Burg, Karen J L; Dréau, Didier

2016-01-01

The extracellular matrix (ECM) contributes to the generation and dynamic of normal breast tissue, in particular to the generation of polarized acinar and ductal structures. In vitro 3D culture conditions, including variations in the composition of the ECM, have been shown to directly influence the formation and organization of acinus-like and duct-like structures. Furthermore, the density of the ECM appears to also play a role in the normal mammary tissue and tumour formation. Here we show that the density of the ECM directly influences the number, organization and function of breast acini. Briefly, non-malignant human breast MCF10A cells were incubated in increasing densities of a Matrigel®-collagen I matrix. Elastic moduli near and distant to the acinus structures were measured by atomic force microscopy, and the number of acinus structures was determined. Immunochemistry was used to investigate the expression levels of E-cadherin, laminin, matrix metalloproteinase-14 and ß-casein in MCF10A cells. The modulus of the ECM was significantly increased near the acinus structures and the number of acinus structures decreased with the increase in Matrigel-collagen I density. As evaluated by the expression of laminin, the organization of the acinus structures present was altered as the density of the ECM increased. Increases in both E-cadherin and MMP14 expression by MCF10A cells as ECM density increased were also observed. In contrast, MCF10A cells expressed lower ß-casein levels as the ECM density increased. Taken together, these observations highlight the key role of ECM density in modulating the number, organization and function of breast acini. Copyright © 2013 John Wiley & Sons, Ltd.

Adapted Boolean network models for extracellular matrix formation

Directory of Open Access Journals (Sweden)

Wollbold Johannes

2009-07-01

Full Text Available Abstract Background Due to the rapid data accumulation on pathogenesis and progression of chronic inflammation, there is an increasing demand for approaches to analyse the underlying regulatory networks. For example, rheumatoid arthritis (RA is a chronic inflammatory disease, characterised by joint destruction and perpetuated by activated synovial fibroblasts (SFB. These abnormally express and/or secrete pro-inflammatory cytokines, collagens causing joint fibrosis, or tissue-degrading enzymes resulting in destruction of the extra-cellular matrix (ECM. We applied three methods to analyse ECM regulation: data discretisation to filter out noise and to reduce complexity, Boolean network construction to implement logic relationships, and formal concept analysis (FCA for the formation of minimal, but complete rule sets from the data. Results First, we extracted literature information to develop an interaction network containing 18 genes representing ECM formation and destruction. Subsequently, we constructed an asynchronous Boolean network with biologically plausible time intervals for mRNA and protein production, secretion, and inactivation. Experimental gene expression data was obtained from SFB stimulated by TGFβ1 or by TNFα and discretised thereafter. The Boolean functions of the initial network were improved iteratively by the comparison of the simulation runs to the experimental data and by exploitation of expert knowledge. This resulted in adapted networks for both cytokine stimulation conditions. The simulations were further analysed by the attribute exploration algorithm of FCA, integrating the observed time series in a fine-tuned and automated manner. The resulting temporal rules yielded new contributions to controversially discussed aspects of fibroblast biology (e.g., considerable expression of TNF and MMP9 by fibroblasts stimulation and corroborated previously known facts (e.g., co-expression of collagens and MMPs after TNF�

ATX-LPA1 axis contributes to proliferation of chondrocytes by regulating fibronectin assembly leading to proper cartilage formation.

Science.gov (United States)

Nishioka, Tatsuji; Arima, Naoaki; Kano, Kuniyuki; Hama, Kotaro; Itai, Eriko; Yukiura, Hiroshi; Kise, Ryoji; Inoue, Asuka; Kim, Seok-Hyung; Solnica-Krezel, Lilianna; Moolenaar, Wouter H; Chun, Jerold; Aoki, Junken

2016-03-23

The lipid mediator lysophosphatidic acid (LPA) signals via six distinct G protein-coupled receptors to mediate both unique and overlapping biological effects, including cell migration, proliferation and survival. LPA is produced extracellularly by autotaxin (ATX), a secreted lysophospholipase D, from lysophosphatidylcholine. ATX-LPA receptor signaling is essential for normal development and implicated in various (patho)physiological processes, but underlying mechanisms remain incompletely understood. Through gene targeting approaches in zebrafish and mice, we show here that loss of ATX-LPA1 signaling leads to disorganization of chondrocytes, causing severe defects in cartilage formation. Mechanistically, ATX-LPA1 signaling acts by promoting S-phase entry and cell proliferation of chondrocytes both in vitro and in vivo, at least in part through β1-integrin translocation leading to fibronectin assembly and further extracellular matrix deposition; this in turn promotes chondrocyte-matrix adhesion and cell proliferation. Thus, the ATX-LPA1 axis is a key regulator of cartilage formation.

Effect of Matrix-Wellbore Flow and Porosity on Pressure Transient Response in Shale Formation Modeling by Dual Porosity and Dual Permeability System

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Daolun Li

2015-01-01

Full Text Available A mathematical dual porosity and dual permeability numerical model based on perpendicular bisection (PEBI grid is developed to describe gas flow behaviors in shale-gas reservoirs by incorporating slippage corrected permeability and adsorbed gas effect. Parametric studies are conducted for a horizontal well with multiple infinite conductivity hydraulic fractures in shale-gas reservoir to investigate effect of matrix-wellbore flow, natural fracture porosity, and matrix porosity. We find that the ratio of fracture permeability to matrix permeability approximately decides the bottom hole pressure (BHP error caused by omitting the flow between matrix and wellbore and that the effect of matrix porosity on BHP is related to adsorption gas content. When adsorbed gas accounts for large proportion of the total gas storage in shale formation, matrix porosity only has a very small effect on BHP. Otherwise, it has obvious influence. This paper can help us understand the complex pressure transient response due to existence of the adsorbed gas and help petroleum engineers to interpret the field data better.

The Biological Observation Matrix (BIOM format or: how I learned to stop worrying and love the ome-ome

Directory of Open Access Journals (Sweden)

McDonald Daniel

2012-07-01

Full Text Available Abstract Background We present the Biological Observation Matrix (BIOM, pronounced “biome” format: a JSON-based file format for representing arbitrary observation by sample contingency tables with associated sample and observation metadata. As the number of categories of comparative omics data types (collectively, the “ome-ome” grows rapidly, a general format to represent and archive this data will facilitate the interoperability of existing bioinformatics tools and future meta-analyses. Findings The BIOM file format is supported by an independent open-source software project (the biom-format project, which initially contains Python objects that support the use and manipulation of BIOM data in Python programs, and is intended to be an open development effort where developers can submit implementations of these objects in other programming languages. Conclusions The BIOM file format and the biom-format project are steps toward reducing the “bioinformatics bottleneck” that is currently being experienced in diverse areas of biological sciences, and will help us move toward the next phase of comparative omics where basic science is translated into clinical and environmental applications. The BIOM file format is currently recognized as an Earth Microbiome Project Standard, and as a Candidate Standard by the Genomic Standards Consortium.

TMEM59 potentiates Wnt signaling by promoting signalosome formation.

Science.gov (United States)

Gerlach, Jan P; Jordens, Ingrid; Tauriello, Daniele V F; van 't Land-Kuper, Ineke; Bugter, Jeroen M; Noordstra, Ivar; van der Kooij, Johanneke; Low, Teck Y; Pimentel-Muiños, Felipe X; Xanthakis, Despina; Fenderico, Nicola; Rabouille, Catherine; Heck, Albert J R; Egan, David A; Maurice, Madelon M

2018-04-09

Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt-FZD assemblies via intramembrane interactions. Subsequently, these Wnt-FZD-TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions. Copyright © 2018 the Author(s). Published by PNAS.

Physiological type I collagen organization induces the formation of a novel class of linear invadosomes

Science.gov (United States)

Juin, Amélie; Billottet, Clotilde; Moreau, Violaine; Destaing, Olivier; Albiges-Rizo, Corinne; Rosenbaum, Jean; Génot, Elisabeth; Saltel, Frédéric

2012-01-01

Invadosomes are F-actin structures capable of degrading the matrix through the activation of matrix metalloproteases. As fibrillar type I collagen promotes pro-matrix metalloproteinase 2 activation by membrane type 1 matrix metalloproteinase, we aimed at investigating the functional relationships between collagen I organization and invadosome induction. We found that fibrillar collagen I induced linear F-actin structures, distributed along the fibrils, on endothelial cells, macrophages, fibroblasts, and tumor cells. These structures share features with conventional invadosomes, as they express cortactin and N-WASP and accumulate the scaffold protein Tks5, which proved essential for their formation. On the basis of their ability to degrade extracellular matrix elements and their original architecture, we named these structures “linear invadosomes.” Interestingly, podosomes or invadopodia were replaced by linear invadosomes upon contact of the cells with fibrillar collagen I. However, linear invadosomes clearly differ from classical invadosomes, as they do not contain paxillin, vinculin, and β1/β3 integrins. Using knockout mouse embryonic fibroblasts and RGD peptide, we demonstrate that linear invadosome formation and activity are independent of β1 and β3 integrins. Finally, linear invadosomes also formed in a three-dimensional collagen matrix. This study demonstrates that fibrillar collagen I is the physiological inducer of a novel class of invadosomes. PMID:22114353

Low nuclear body formation and tax SUMOylation do not prevent NF-kappaB promoter activation

Directory of Open Access Journals (Sweden)

Bonnet Amandine

2012-09-01

Full Text Available Abstract Background The Tax protein encoded by Human T-lymphotropic virus type 1 (HTLV-1 is a powerful activator of the NF-κB pathway, a property critical for HTLV-1-induced immortalization of CD4+ T lymphocytes. Tax permanently stimulates this pathway at a cytoplasmic level by activating the IκB kinase (IKK complex and at a nuclear level by enhancing the binding of the NF-κB factor RelA to its cognate promoters and by forming nuclear bodies, believed to represent transcriptionally active structures. In previous studies, we reported that Tax ubiquitination and SUMOylation play a critical role in Tax localization and NF-κB activation. Indeed, analysis of lysine Tax mutants fused or not to ubiquitin or SUMO led us to propose a two-step model in which Tax ubiquitination first intervenes to activate IKK while Tax SUMOylation is subsequently required for promoter activation within Tax nuclear bodies. However, recent studies showing that ubiquitin or SUMO can modulate Tax activities in either the nucleus or the cytoplasm and that SUMOylated Tax can serve as substrate for ubiquitination suggested that Tax ubiquitination and SUMOylation may mediate redundant rather than successive functions. Results In this study, we analyzed the properties of a new Tax mutant that is properly ubiquitinated, but defective for both nuclear body formation and SUMOylation. We report that reducing Tax SUMOylation and nuclear body formation do not alter the ability of Tax to activate IKK, induce RelA nuclear translocation, and trigger gene expression from a NF-κB promoter. Importantly, potent NF-κB promoter activation by Tax despite low SUMOylation and nuclear body formation is also observed in T cells, including CD4+ primary T lymphocytes. Moreover, we show that Tax nuclear bodies are hardly observed in HTLV-1-infected T cells. Finally, we provide direct evidence that the degree of NF-κB activation by Tax correlates with the level of Tax ubiquitination, but not

Low nuclear body formation and tax SUMOylation do not prevent NF-kappaB promoter activation.

Science.gov (United States)

Bonnet, Amandine; Randrianarison-Huetz, Voahangy; Nzounza, Patrycja; Nedelec, Martine; Chazal, Maxime; Waast, Laetitia; Pene, Sabrina; Bazarbachi, Ali; Mahieux, Renaud; Bénit, Laurence; Pique, Claudine

2012-09-25

The Tax protein encoded by Human T-lymphotropic virus type 1 (HTLV-1) is a powerful activator of the NF-κB pathway, a property critical for HTLV-1-induced immortalization of CD4⁺ T lymphocytes. Tax permanently stimulates this pathway at a cytoplasmic level by activating the IκB kinase (IKK) complex and at a nuclear level by enhancing the binding of the NF-κB factor RelA to its cognate promoters and by forming nuclear bodies, believed to represent transcriptionally active structures. In previous studies, we reported that Tax ubiquitination and SUMOylation play a critical role in Tax localization and NF-κB activation. Indeed, analysis of lysine Tax mutants fused or not to ubiquitin or SUMO led us to propose a two-step model in which Tax ubiquitination first intervenes to activate IKK while Tax SUMOylation is subsequently required for promoter activation within Tax nuclear bodies. However, recent studies showing that ubiquitin or SUMO can modulate Tax activities in either the nucleus or the cytoplasm and that SUMOylated Tax can serve as substrate for ubiquitination suggested that Tax ubiquitination and SUMOylation may mediate redundant rather than successive functions. In this study, we analyzed the properties of a new Tax mutant that is properly ubiquitinated, but defective for both nuclear body formation and SUMOylation. We report that reducing Tax SUMOylation and nuclear body formation do not alter the ability of Tax to activate IKK, induce RelA nuclear translocation, and trigger gene expression from a NF-κB promoter. Importantly, potent NF-κB promoter activation by Tax despite low SUMOylation and nuclear body formation is also observed in T cells, including CD4⁺ primary T lymphocytes. Moreover, we show that Tax nuclear bodies are hardly observed in HTLV-1-infected T cells. Finally, we provide direct evidence that the degree of NF-κB activation by Tax correlates with the level of Tax ubiquitination, but not SUMOylation. These data reveal that the

Matrix density alters zyxin phosphorylation, which limits peripheral process formation and extension in endothelial cells invading 3D collagen matrices.

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Abbey, Colette A; Bayless, Kayla J

2014-09-01

This study was designed to determine the optimal conditions required for known pro-angiogenic stimuli to elicit successful endothelial sprouting responses. We used an established, quantifiable model of endothelial cell (EC) sprout initiation where ECs were tested for invasion in low (1 mg/mL) and high density (5 mg/mL) 3D collagen matrices. Sphingosine 1-phosphate (S1P) alone, or S1P combined with stromal derived factor-1α (SDF) and phorbol ester (TPA), elicited robust sprouting responses. The ability of these factors to stimulate sprouting was more effective in higher density collagen matrices. S1P stimulation resulted in a significant increase in invasion distance, and with the exception of treatment groups containing phorbol ester, invasion distance was longer in 1mg/mL compared to 5mg/mL collagen matrices. Closer examination of cell morphology revealed that increasing matrix density and supplementing with SDF and TPA enhanced the formation of multicellular structures more closely resembling capillaries. TPA enhanced the frequency and size of lumen formation and correlated with a robust increase in phosphorylation of p42/p44 Erk kinase, while S1P and SDF did not. Also, a higher number of significantly longer extended processes formed in 5mg/mL compared to 1mg/mL collagen matrices. Because collagen matrices at higher density have been reported to be stiffer, we tested for changes in the mechanosensitive protein, zyxin. Interestingly, zyxin phosphorylation levels inversely correlated with matrix density, while levels of total zyxin did not change significantly. Immunofluorescence and localization studies revealed that total zyxin was distributed evenly throughout invading structures, while phosphorylated zyxin was slightly more intense in extended peripheral processes. Silencing zyxin expression increased extended process length and number of processes, while increasing zyxin levels decreased extended process length. Altogether these data indicate that ECs

Role of myeloperoxidase in abdominal aortic aneurysm formation: mitigation by taurine.

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Kim, Ha Won; Blomkalns, Andra L; Ogbi, Mourad; Thomas, Manesh; Gavrila, Daniel; Neltner, Bonnie S; Cassis, Lisa A; Thompson, Robert W; Weiss, Robert M; Lindower, Paul D; Blanco, Victor M; McCormick, Michael L; Daugherty, Alan; Fu, Xiaoming; Hazen, Stanley L; Stansfield, Brian K; Huo, Yuqing; Fulton, David J; Chatterjee, Tapan; Weintraub, Neal L

2017-12-01

Oxidative stress plays a fundamental role in abdominal aortic aneurysm (AAA) formation. Activated polymorphonuclear leukocytes (or neutrophils) are associated with AAA and express myeloperoxidase (MPO), which promotes inflammation, matrix degradation, and other pathological features of AAA, including enhanced oxidative stress through generation of reactive oxygen species. Both plasma and aortic MPO levels are elevated in patients with AAA, but the role of MPO in AAA pathogenesis has, heretofore, never been investigated. Here, we show that MPO gene deletion attenuates AAA formation in two animal models: ANG II infusion in apolipoprotein E-deficient mice and elastase perfusion in C57BL/6 mice. Oral administration of taurine [1% or 4% (wt/vol) in drinking water], an amino acid known to react rapidly with MPO-generated oxidants like hypochlorous acid, also prevented AAA formation in the ANG II and elastase models as well as the CaCl 2 application model of AAA formation while reducing aortic peroxidase activity and aortic protein-bound dityrosine levels, an oxidative cross link formed by MPO. Both MPO gene deletion and taurine supplementation blunted aortic macrophage accumulation, elastin fragmentation, and matrix metalloproteinase activation, key features of AAA pathogenesis. Moreover, MPO gene deletion and taurine administration significantly attenuated the induction of serum amyloid A, which promotes ANG II-induced AAAs. These data implicate MPO in AAA pathogenesis and suggest that studies exploring whether taurine can serve as a potential therapeutic for the prevention or treatment of AAA in patients merit consideration. NEW & NOTEWORTHY Neutrophils are abundant in abdominal aortic aneurysm (AAA), and myeloperoxidase (MPO), prominently expressed in neutrophils, is associated with AAA in humans. This study demonstrates that MPO gene deletion or supplementation with the natural product taurine, which can scavenge MPO-generated oxidants, can prevent AAA formation

Chondrogenic properties of collagen type XI, a component of cartilage extracellular matrix.

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Li, Ang; Wei, Yiyong; Hung, Clark; Vunjak-Novakovic, Gordana

2018-08-01

Cartilage extracellular matrix (ECM) has been used for promoting tissue engineering. However, the exact effects of ECM on chondrogenesis and the acting mechanisms are not well understood. In this study, we investigated the chondrogenic effects of cartilage ECM on human mesenchymal stem cells (MSCs) and identified the contributing molecular components. To this end, a preparation of articular cartilage ECM was supplemented to pellets of chondrogenically differentiating MSCs, pellets of human chondrocytes, and bovine articular cartilage explants to evaluate the effects on cell proliferation and the production of cartilaginous matrix. Selective enzymatic digestion and screening of ECM components were conducted to identify matrix molecules with chondrogenic properties. Cartilage ECM promoted MSC proliferation, production of cartilaginous matrix, and maturity of chondrogenic differentiation, and inhibited the hypertrophic differentiation of MSC-derived chondrocytes. Selective digestion of ECM components revealed a contributory role of collagens in promoting chondrogenesis. The screening of various collagen subtypes revealed strong chondrogenic effect of collagen type XI. Finally, collagen XI was found to promote production and inhibit degradation of cartilage matrix in human articular chondrocyte pellets and bovine articular cartilage explants. Our results indicate that cartilage ECM promotes chondrogenesis and inhibits hypertrophic differentiation in MSCs. Collagen type XI is the ECM component that has the strongest effects on enhancing the production and inhibiting the degradation of cartilage matrix. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kartogenin with PRP promotes the formation of fibrocartilage zone in the tendon-bone interface.

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Zhou, Yiqin; Zhang, Jianying; Yang, Jinsong; Narava, Manoj; Zhao, Guangyi; Yuan, Ting; Wu, Haishan; Zheng, Nigel; Hogan, MaCalus V; Wang, James H-C

2017-12-01

Treatment of tendon-bone junction injuries is a challenge because tendon-bone interface often heals poorly and the fibrocartilage zone, which reduces stress concentration, at the interface is not formed. In this study, we used a compound called kartogenin (KGN) with platelet-rich plasma (PRP) to induce the formation of fibrocartilage zone in a rat tendon graft-bone tunnel model. The experimental rats received KGN-PRP or PRP injections in the tendon graft-bone tunnel interface. The control group received saline. After 4, 8 and 12 weeks, Safranin O staining of the tendon graft-bone tunnels revealed abundant proteoglycans in the KGN-PRP group indicating the formation of cartilage-like transition zone. Immunohistochemical and immuno-fluorescence staining revealed collagen types I (Col-I) and II (Col-II) in the newly formed fibrocartilage zone. Both fibrocartilage zone formation and maturation were healing time dependent. In contrast, the PRP and saline control groups had no cartilage-like tissues and minimal Col-I and Col-II staining. Some gaps were also present in the saline control group. Finally, pull-out strength in the KGN-PRP-treated group at 8 weeks was 1.4-fold higher than the PRP-treated group and 1.6-fold higher than the saline control group. These findings indicate that KGN, with PRP as a carrier, promotes the formation of fibrocartilage zone between the tendon graft and bone interface. Thus, KGN-PRP may be used as a convenient cell-free therapy in clinics to promote fibrocartilage zone formation in rotator calf repair and anterior cruciate ligament reconstruction, thereby enhancing the mechanical strength of the tendon-bone interface and hence the clinical outcome of these procedures. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates

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Bartlett, John D.

2013-01-01

This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389

Three-dimensional piezoelectric fibrous scaffolds selectively promote mesenchymal stem cell differentiation.

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Damaraju, Sita M; Shen, Yueyang; Elele, Ezinwa; Khusid, Boris; Eshghinejad, Ahmad; Li, Jiangyu; Jaffe, Michael; Arinzeh, Treena Livingston

2017-12-01

The discovery of electric fields in biological tissues has led to efforts in developing technologies utilizing electrical stimulation for therapeutic applications. Native tissues, such as cartilage and bone, exhibit piezoelectric behavior, wherein electrical activity can be generated due to mechanical deformation. Yet, the use of piezoelectric materials have largely been unexplored as a potential strategy in tissue engineering, wherein a piezoelectric biomaterial acts as a scaffold to promote cell behavior and the formation of large tissues. Here we show, for the first time, that piezoelectric materials can be fabricated into flexible, three-dimensional fibrous scaffolds and can be used to stimulate human mesenchymal stem cell differentiation and corresponding extracellular matrix/tissue formation in physiological loading conditions. Piezoelectric scaffolds that exhibit low voltage output, or streaming potential, promoted chondrogenic differentiation and piezoelectric scaffolds with a high voltage output promoted osteogenic differentiation. Electromechanical stimulus promoted greater differentiation than mechanical loading alone. Results demonstrate the additive effect of electromechanical stimulus on stem cell differentiation, which is an important design consideration for tissue engineering scaffolds. Piezoelectric, smart materials are attractive as scaffolds for regenerative medicine strategies due to their inherent electrical properties without the need for external power sources for electrical stimulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Urokinase receptor expression on human microvascular endothelial cells is increased by hypoxia: Implications for capillary-like tube formation in a fibrin matrix

NARCIS (Netherlands)

Kroon, M.E.; Koolwijk, P.; Vecht, B. van der; Hinsbergh, V.W.M. van

2000-01-01

Hypoxia stimulates angiogenesis, the formation of new blood vessels. This study evaluates the direct effect of hypoxia (1% oxygen) on the angiogenic response of human microvascular endothelial cells (hMVECs) seeded on top of a 3-dimensional fibrin matrix, hMVECs stimulated with fibroblast growth

In situ formation of ZrB2 particulates and their influence on microstructure and tensile behavior of AA7075 aluminum matrix composites

Directory of Open Access Journals (Sweden)

J. David Raja Selvam

2017-02-01

Full Text Available In situ synthesis of aluminum matrix composites (AMCs has become a popular method due to several advantages over conventional stir casting method. In the present study, AA7075/ZrB2 AMCs reinforced with various content of ZrB2 particulates (0, 3, 6, 9 and 12 wt.% were synthesized by the in situ reaction of molten aluminum with inorganic salts K2ZrF6 and KBF4. The composites were characterized using XRD, OM, SEM, EBSD and TEM. The XRD patterns revealed the formation of ZrB2 particulates without the presence of any other compounds. The formation of ZrB2 particulates refined the grains of aluminum matrix extensively. Most of the ZrB2 particulates were located near the grain boundaries. The ZrB2 particulates exhibited various morphologies including spherical, cylindrical and hexagonal shapes. The size of the ZrB2 particulates was in the order of nano, sub micron and micron level. A good interfacial bonding was observed between the aluminum matrix and the ZrB2 particulates. The in situ formed ZrB2 particulates enhanced the mechanical properties such as microhardness and the ultimate tensile strength. Various strengthening mechanisms were identified.

Effect of 3D-scaffold formation on differentiation and survival in human neural progenitor cells.

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Ortinau, Stefanie; Schmich, Jürgen; Block, Stephan; Liedmann, Andrea; Jonas, Ludwig; Weiss, Dieter G; Helm, Christiane A; Rolfs, Arndt; Frech, Moritz J

2010-11-11

3D-scaffolds have been shown to direct cell growth and differentiation in many different cell types, with the formation and functionalisation of the 3D-microenviroment being important in determining the fate of the embedded cells. Here we used a hydrogel-based scaffold to investigate the influences of matrix concentration and functionalisation with laminin on the formation of the scaffolds, and the effect of these scaffolds on human neural progenitor cells cultured within them. In this study we used different concentrations of the hydrogel-based matrix PuraMatrix. In some experiments we functionalised the matrix with laminin I. The impact of concentration and treatment with laminin on the formation of the scaffold was examined with atomic force microscopy. Cells from a human fetal neural progenitor cell line were cultured in the different matrices, as well as in a 2D culture system, and were subsequently analysed with antibody stainings against neuronal markers. In parallel, the survival rate of the cells was determined by a live/dead assay. Atomic force microscopy measurements demonstrated that the matrices are formed by networks of isolated PuraMatrix fibres and aggregates of fibres. An increase of the hydrogel concentration led to a decrease in the mesh size of the scaffolds and functionalisation with laminin promoted aggregation of the fibres (bundle formation), which further reduces the density of isolated fibres. We showed that laminin-functionalisation is essential for human neural progenitor cells to build up 3D-growth patterns, and that proliferation of the cells is also affected by the concentration of matrix. In addition we found that 3D-cultures enhanced neuronal differentiation and the survival rate of the cells compared to 2D-cultures. Taken together, we have demonstrated a direct influence of the 3D-scaffold formation on the survival and neuronal differentiation of human neural progenitor cells. These findings emphasize the importance of optimizing 3

Altered Liver Proteoglycan/Glycosaminoglycan Structure as a Manifestation of Extracellular Matrix Remodeling upon BCG-induced Granulomatosis in Mice.

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Kim, L B; Shkurupy, V A; Putyatina, A N

2017-01-01

Experimental BCG-induced granulomatosis in mice was used to study changes in the dynamics of individual liver proteoglycan components reflecting phasic extracellular matrix remodeling, determined by the host-parasite interaction and associated with granuloma development. In the early BCG-granulomatosis period, the increase in individual proteoglycan components promotes granuloma formation, providing conditions for mycobacteria adhesion to host cells, migration of phagocytic cells from circulation, and cell-cell interaction leading to granuloma development and fibrosis. Later, reduced reserve capacity of the extracellular matrix, development of interstitial fibrosis and granuloma fibrosis can lead to trophic shortage for cells within the granulomas, migration of macrophages out of them, and development of spontaneous necrosis and apoptosis typical of tuberculosis.

Matrix metalloproteinase (MMP) 9 transcription in mouse brain induced by fear learning.

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Ganguly, Krishnendu; Rejmak, Emilia; Mikosz, Marta; Nikolaev, Evgeni; Knapska, Ewelina; Kaczmarek, Leszek

2013-07-19

Memory formation requires learning-based molecular and structural changes in neurons, whereas matrix metalloproteinase (MMP) 9 is involved in the synaptic plasticity by cleaving extracellular matrix proteins and, thus, is associated with learning processes in the mammalian brain. Because the mechanisms of MMP-9 transcription in the brain are poorly understood, this study aimed to elucidate regulation of MMP-9 gene expression in the mouse brain after fear learning. We show here that contextual fear conditioning markedly increases MMP-9 transcription, followed by enhanced enzymatic levels in the three major brain structures implicated in fear learning, i.e. the amygdala, hippocampus, and prefrontal cortex. To reveal the role of AP-1 transcription factor in MMP-9 gene expression, we have used reporter gene constructs with specifically mutated AP-1 gene promoter sites. The constructs were introduced into the medial prefrontal cortex of neonatal mouse pups by electroporation, and the regulation of MMP-9 transcription was studied after contextual fear conditioning in the adult animals. Specifically, -42/-50- and -478/-486-bp AP-1 binding motifs of the mouse MMP-9 promoter sequence have been found to play a major role in MMP-9 gene activation. Furthermore, increases in MMP-9 gene promoter binding by the AP-1 transcription factor proteins c-Fos and c-Jun have been demonstrated in all three brain structures under investigation. Hence, our results suggest that AP-1 acts as a positive regulator of MMP-9 transcription in the brain following fear learning.

Mechanics and crack formation in the extracellular matrix with articular cartilage as a model system

Science.gov (United States)

Kearns, Sarah; Silverberg, Jesse; Bonassar, Lawrence; Cohen, Itai; Das, Moumita

We investigate the mechanical structure-function relations in the extracellular matrix (ECM) with focus on crack formation and failure. As a model system, our study focuses on the ECM in articular cartilage (AC), the tissue that covers the ends of bones, and distributes load in joints including in the knees, shoulders, and hips. The strength, toughness, and crack resistance of native articular cartilage is unparalleled in materials made by humankind. This mechanical response is mainly due to its ECM. The ECM in AC has two major mechanobiological components: a network of the biopolymer collagen and a flexible aggrecan gel. We model this system as a biopolymer network embedded in a swelling gel, and investigate the conditions for the formation and propagation of cracks using a combination of rigidity percolation theory and energy minimization approaches. Our results may provide useful insights into the design principles of the ECM as well as of biomimetic hydrogels that are mechanically robust and can, at the same time, easily adapt to cues in their surroundings. This work was partially supported by a Cottrell College Science Award.

Podoplanin promotes progression of malignant pleural mesothelioma by regulating motility and focus formation.

Science.gov (United States)

Takeuchi, Shinji; Fukuda, Koji; Yamada, Tadaaki; Arai, Sachiko; Takagi, Satoshi; Ishii, Genichiro; Ochiai, Atsushi; Iwakiri, Shotaro; Itoi, Kazumi; Uehara, Hisanori; Nishihara, Hiroshi; Fujita, Naoya; Yano, Seiji

2017-04-01

Malignant pleural mesothelioma (MPM) is characterized by dissemination and aggressive growth in the thoracic cavity. Podoplanin (PDPN) is an established diagnostic marker for MPM, but the function of PDPN in MPM is not fully understood. The purpose of this study was to determine the pathogenetic function of PDPN in MPM. Forty-seven of 52 tumors (90%) from Japanese patients with MPM and 3/6 (50%) MPM cell lines tested positive for PDPN. Knocking down PDPN in PDPN-high expressing MPM cells resulted in decreased cell motility. In contrast, overexpression of PDPN in PDPN-low expressing MPM cells enhanced cell motility. PDPN stimulated motility was mediated by activation of the RhoA/ROCK pathway. Moreover, knocking down PDPN with short hairpin (sh) RNA in PDPN-high expressing MPM cells resulted in decreased development of a thoracic tumor in mice with severe combined immune deficiency (SCID). In sharp contrast, transfection of PDPN in PDPN-low expressing MPM cells resulted in an increase in the number of Ki-67-positive proliferating tumor cells and it promoted progression of a thoracic tumor in SCID mice. Interestingly, PDPN promoted focus formation in vitro, and a low level of E-cadherin expression and YAP1 activation was observed in PDPN-high MPM tumors. These findings indicate that PDPN is a diagnostic marker as well as a pathogenetic regulator that promotes MPM progression by increasing cell motility and inducing focus formation. Therefore, PDPN might be a pathogenetic determinant of MPM dissemination and aggressive growth and may thus be an ideal therapeutic target. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Reduction of Inflammatory Responses and Enhancement of Extracellular Matrix Formation by Vanillin-Incorporated Poly(Lactic-co-Glycolic Acid) Scaffolds

OpenAIRE

Lee, Yujung; Kwon, Jeongil; Khang, Gilson; Lee, Dongwon

2012-01-01

Vanillin is one of the major components of vanilla, a commonly used flavoring agent and preservative and is known to exert potent antioxidant and anti-inflammatory activities. In this work, vanillin-incorporated poly(lactic-co-glycolic acid) (PLGA) films and scaffolds were fabricated to evaluate the effects of vanillin on the inflammatory responses and extracellular matrix (ECM) formation in vitro and in vivo. The incorporation of vanillin to PLGA films induced hydrophilic nature, resulting i...

Transcriptional factor DLX3 promotes the gene expression of enamel matrix proteins during amelogenesis.

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Zhang, Zhichun; Tian, Hua; Lv, Ping; Wang, Weiping; Jia, Zhuqing; Wang, Sainan; Zhou, Chunyan; Gao, Xuejun

2015-01-01

Mutation of distal-less homeobox 3 (DLX3) is responsible for human tricho-dento-osseous syndrome (TDO) with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP) genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO) inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.

Vibration acceleration promotes bone formation in rodent models.

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Ryohei Uchida

BV in the centrifuge acceleration group had no significant difference compared those in control-CA group. Union rate and BV in the low-magnitude group of RFH model were also significantly higher than those in the other groups (Union rate: 60% v.s. 0% in the high-magnitude group and 10% in the control-VA group, BV: 0.69±0.30mm3 v.s. 0.15±0.09mm3 in high-magnitude group and 0.22±0.17mm3 in control-VA group. BV/TV in the low-magnitude group of RFH model was significantly higher than that in control-VA group (59.4±14.9% v.s. 35.8±13.5%. On the other hand, radiographic union rate (10% in centrifuge acceleration group v.s. 20% in control-CA group and micro-CT parameters in RFH model were not significantly different between two groups in the constant acceleration studies. Radiographic images of non-union rib fractures showed cartilage at the fracture site and poor new bone formation, whereas union samples showed only new bone. In conclusion, low-magnitude vibration acceleration promoted bone formation at the trunk in both BMP-induced ectopic bone formation and rib fracture healing models. However, the micro-CT parameters were not similar between two models, which suggested that there might be difference in the mechanism of effect by vibration between two models.

Influence of boron on ferrite formation in copper-added spheroidal graphite cast iron

Directory of Open Access Journals (Sweden)

Ying Zou

2014-07-01

Full Text Available This paper reviews the original work of the authors published recently, describing the influence of B on the matrix of the Cuadded spheroidal graphite cast iron. The effect of Cu has been corrected as a ferrite formation promoter in the matrix of the grey cast iron by the usage of high-purity material. Also, this paper focuses on the ferrite formation and the observation of the Cu distribution in the B-added and B-free Cu-containing spheroidal graphite cast iron. The Cu film on the spheroidal graphite can be successfully observed in the B-free sample using a special etching method. However, in the B-added sample, no Cu film could be found, while the secondary graphite was formed on the surface of the spheroidal graphite. The interaction between B and Cu is stressed as a peculiar phenomenon by the employment of a contrast experiment of B and Mn. The heat treatment could make Cu precipitate more significantly in the eutectic cells and in the matrix in the form of large Cu particles because of the limited solubility of Cu.

Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes.

Science.gov (United States)

Hobley, Laura; Harkins, Catriona; MacPhee, Cait E; Stanley-Wall, Nicola R

2015-09-01

Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars. © FEMS 2015.

Human recombinant cementum attachment protein (hrPTPLa/CAP) promotes hydroxyapatite crystal formation in vitro and bone healing in vivo.

Science.gov (United States)

Montoya, Gonzalo; Arenas, Jesús; Romo, Enrique; Zeichner-David, Margarita; Alvarez, Marco; Narayanan, A Sampath; Velázquez, Ulises; Mercado, Gabriela; Arzate, Higinio

2014-12-01

Cementum extracellular matrix is similar to other mineralized tissues; however, this unique tissue contains molecules only present in cementum. A cDNA of these molecules, cementum attachment protein (hrPTPLa/CAP) was cloned and expressed in a prokaryotic system. This molecule is an alternative splicing of protein tyrosine phosphatase-like A (PTPLa). In this study, we wanted to determine the structural and functional characteristics of this protein. Our results indicate that hrPTPLa/CAP contains a 43.2% α-helix, 8.9% β-sheet, 2% β-turn and 45.9% random coil secondary structure. Dynamic light scattering shows that this molecule has a size distribution of 4.8 nm and aggregates as an estimated mass of 137 kDa species. AFM characterization and FE-SEM studies indicate that this protein self-assembles into nanospheres with sizes ranging from 7.0 to 27 nm in diameter. Functional studies demonstrate that hrPTPLa/CAP promotes hydroxyapatite crystal nucleation: EDS analysis revealed that hrPTPLa/CAP-induced crystals had a 1.59 ± 0.06 Ca/P ratio. Further confirmation with MicroRaman spectrometry and TEM confirm the presence of hydroxyapatite. In vivo studies using critical-size defects in rat cranium showed that hrPTPLa/CAP promoted 73% ± 2.19% and 87% ± 1.97% new bone formation at 4 and 8 weeks respectively. Although originally identified in cementum, PTPLa/CAP is very effective at inducing bone repair and healing and therefore this novel molecule has a great potential to be used for mineralized tissue bioengineering and tissue regeneration. Copyright © 2014 Elsevier Inc. All rights reserved.

Formation of Neural Networks in 3D Scaffolds Fabricated by Means of Laser Microstereolithography.

Science.gov (United States)

Vedunova, M V; Timashev, P S; Mishchenko, T A; Mitroshina, E V; Koroleva, A V; Chichkov, B N; Panchenko, V Ya; Bagratashvili, V N; Mukhina, I V

2016-08-01

We developed and tested new 3D scaffolds for neurotransplantation. Scaffolds of predetermined architectonic were prepared using microstereolithography technique. Scaffolds were highly biocompatible with the nervous tissue cells. In vitro studies showed that the material of fabricated scaffolds is not toxic for dissociated brain cells and promotes the formation of functional neural networks in the matrix. These results demonstrate the possibility of fabrication of tissue-engineering constructs for neurotransplantation based on created scaffolds.

Etanercept Promotes Bone Formation via Suppression of Dickkopf-1 Expression in Rats with Collagen-Induced Arthritis

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Tanida, Atsushi; Kishimoto, Yuji; Okano, Toru; Hagino, Hiroshi

2013-01-01

Background Various clinical reports suggest etanercept (ETN) has some efficacy in bone formation in rheumatoid arthritis (RA). To examine this effect, we investigated the gene expression of cytokines relevant to osteoblast/osteoclast differentiation, and evaluated histomorphometric findings in mature rats with collagen-induced arthritis (CIA). Methods Total RNA was extracted from knee joints with CIA after ETN or placebo administration. Subsequently, realtime-PCR was carried out to quantify the mRNAs encoding Wnt-1, Dickkopf-1 (DKK-1), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegelin (OPG) and TNF (tumor necrosis factor)-alpha. In histomorphometric analysis, the infiltrating pannus volume and pannus surface, and the following items in contact with pannus surface were measured: osteoclast number, osteoid surface, osteoid volume and labeling surface. These were evaluated in the distal femur with CIA with or without ETN administration. Results TNF-alpha, RANKL and OPG mRNA expressions, linked to osteoclastogenesis, were not significantly different with or without ETN administration. ETN administration significantly increased Wnt-1 mRNA expression, the osteoblast promoter, and decreased DKK-1 mRNA expression, the Wnt signal inhibitor. In histomorphometric analysis, pannus volume, pannus surface and osteoclast number, parameters of bone destruction, were not significantly different among groups. Osteoid volume, osteoid surface and labeling surface, parameters of bone formation, increased significantly with ETN administration. Conclusion Our results suggest that ETN suppresses DDK-1 expression, and, as a result, Wnt expression is promoted and osteoblastogenesis becomes more active, independent of the regulation of osteoclast activity. Marked bone formation is attributed to the fact that ETN directly promotes osteoblastogenesis, not as a result of suppressing osteoclastogenesis. PMID:24031147

Enamel matrix derivative enhances tissue formation around scaffolds used for tissue engineering of ligaments.

Science.gov (United States)

Messenger, Michael P; Raïf, El M; Seedhom, Bahaa B; Brookes, Steven J

2010-02-01

The following in vitro translational study investigated whether enamel matrix derivative (EMD), an approved biomimetic treatment for periodontal disease (Emdogain) and hard-to-heal wounds (Xelma), enhanced synovial cell colonization and protein synthesis around a scaffold used clinically for in situ tissue engineering of the torn anterior cruciate ligament (ACL). Synovial cells were enzymatically extracted from bovine synovium and dynamically seeded onto polyethylene terephthalate (PET) scaffolds. The cells were cultured in low-serum medium (0.5% FBS) for 4 weeks with either a single administration of EMD at the start of the 4 week period or multiple administrations of EMD at regular intervals throughout the 4 weeks. Samples were harvested and evaluated using the Hoechst DNA assay, BCA protein assay, cresolphthalein complexone calcium assay, SDS-PAGE, ELISA and electron microscopy. A significant increase in cell number (DNA) (p < 0.01), protein content (p < 0.01) and TGFbeta1 synthesis (p < 0.01) was observed with multiple administrations of EMD. Additionally, SDS-PAGE showed an increase in high molecular weight proteins, characteristic of the fibril-forming collagens. Electron microscopy supported these findings, showing that scaffolds treated with multiple administrations of EMD were heavily coated with cells and extracellular matrix (ECM) that enveloped the fibres. Multiple administrations of EMD to synovial cell-seeded scaffolds enhanced the formation of tissue in vitro. Additionally, it was shown that EMD enhanced TGFbeta1 synthesis of synovial cells, suggesting a potential mode of action for EMD's capacity to stimulate tissue regeneration.

Shaping Synapses by the Neural Extracellular Matrix

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Maura Ferrer-Ferrer

2018-05-01

Full Text Available Accumulating data support the importance of interactions between pre- and postsynaptic neuronal elements with astroglial processes and extracellular matrix (ECM for formation and plasticity of chemical synapses, and thus validate the concept of a tetrapartite synapse. Here we outline the major mechanisms driving: (i synaptogenesis by secreted extracellular scaffolding molecules, like thrombospondins (TSPs, neuronal pentraxins (NPs and cerebellins, which respectively promote presynaptic, postsynaptic differentiation or both; (ii maturation of synapses via reelin and integrin ligands-mediated signaling; and (iii regulation of synaptic plasticity by ECM-dependent control of induction and consolidation of new synaptic configurations. Particularly, we focused on potential importance of activity-dependent concerted activation of multiple extracellular proteases, such as ADAMTS4/5/15, MMP9 and neurotrypsin, for permissive and instructive events in synaptic remodeling through localized degradation of perisynaptic ECM and generation of proteolytic fragments as inducers of synaptic plasticity.

Nitrite promotes protein carbonylation and Strecker aldehyde formation in experimental fermented sausages: are both events connected?

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Villaverde, A; Ventanas, J; Estévez, M

2014-12-01

The role played by curing agents (nitrite, ascorbate) on protein oxidation and Strecker aldehyde formation is studied. To fulfill this objective, increasing concentrations of nitrite (0, 75 and 150ppm) and ascorbate (0, 250 and 500ppm) were added to sausages subjected to a 54day drying process. The concurrence of intense proteolysis, protein carbonylation and formation of Strecker aldehydes during processing of sausages suggests that α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) may be implicated in the formation of Strecker aldehydes. The fact that nitrite (150ppm, ingoing amount) significantly promoted the formation of protein carbonyls at early stages of processing and the subsequent formation of Strecker aldehydes provides strength to this hypothesis. Ascorbate (125 and 250ppm) controlled the overall extent of protein carbonylation in sausages without declining the formation of Strecker aldehydes. These results may contribute to understanding the chemistry fundamentals of the positive influence of nitrite on the flavor and overall acceptability of cured muscle foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

Implication of the oligomeric state of the N-terminal PTX3 domain in cumulus matrix assembly.

Science.gov (United States)

Ievoli, Elena; Lindstedt, Ragnar; Inforzato, Antonio; Camaioni, Antonella; Palone, Francesca; Day, Anthony J; Mantovani, Alberto; Salvatori, Giovanni; Salustri, Antonietta

2011-06-01

Pentraxin 3 (PTX3) plays a key role in the formation of the hyaluronan-rich matrix of the cumulus oophorus surrounding ovulated eggs that is required for successful fertilization and female fertility. PTX3 is a multimeric protein consisting of eight identical protomers held together by a combination of non-covalent interactions and disulfide bonds. Recent findings suggest that the oligomeric status of PTX3 is important for stabilizing the cumulus matrix. Because the role of PTX3 in the cumulus resides in the unique N-terminal sequence of the protomer, we investigated further this issue by testing the ability of distinct Cys/Ser mutants of recombinant N-terminal region of PTX3 (N(_)PTX3) with different oligomeric arrangement to promote in vitro normal expansion in cumuli from Ptx3-null mice. Here we report that the dimer of the N(_)PTX3 is unable to rescue cumulus matrix organization, and that the tetrameric assembly of the protein is the minimal oligomeric state required for accomplishing this function. We have previously demonstrated that PTX3 binds to HCs of IαI and TSG-6, which are essential for cumulus matrix formation and able to interact with hyaluronan. Interestingly, here we show by solid-phase binding experiments that the dimer of the N(_)PTX3 retains the ability to bind to both IαI and TSG-6, suggesting that the octameric structure of PTX3 provides multiple binding sites for each of these ligands. These findings support the hypothesis that PTX3 contributes to cumulus matrix organization by cross-linking HA polymers through interactions with multiple HCs of IαI and/or TSG-6. The N-terminal PTX3 tetrameric oligomerization was recently reported to be also required for recognition and inhibition of FGF2. Given that this growth factor has been detected in the mammalian preovulatory follicle, we wondered whether FGF2 negatively influences cumulus expansion and PTX3 may also serve in vivo to antagonize its activity. We found that a molar excess of FGF2, above

Service Innovation by Industrial Cluster Formation and Export Promotion

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Noleen Pisa

2017-12-01

Full Text Available Service innovation drives economic growth and structural change by stimulating the development of new sectors and productivity improvements in existing sectors. Resource based sectors are the main contributors to South Africa’s North West province’s economic output This paper illustrates how such a region can use industrial cluster formation and focused export promotion as a strategy to enhance service innovation. Four service clusters were identified within the above mentioned province through structural path analysis and power of pull methods. An export market selection model is applied to the identified service industrial clusters to reveal realistic export opportunities associated with each cluster. Finally, trade multipliers are used to show the spill-over benefits given an increase in the clusters’ exports. Policymakers can use these results to inform actions that may assist in the development of these services clusters to strengthen the province’s competitive advantage and diversify its output.

The FAK–Arp2/3 interaction promotes leading edge advance and haptosensing by coupling nascent adhesions to lamellipodia actin

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Swaminathan, Vinay; Fischer, R. S.; Waterman, Clare M.

2016-01-01

Cell migration is initiated in response to biochemical or physical cues in the environment that promote actin-mediated lamellipodial protrusion followed by the formation of nascent integrin adhesions (NAs) within the protrusion to drive leading edge advance. Although FAK is known to be required for cell migration through effects on focal adhesions, its role in NA formation and lamellipodial dynamics is unclear. Live-cell microscopy of FAK−/− cells with expression of phosphorylation deficient or a FERM-domain mutant deficient in Arp2/3 binding revealed a requirement for FAK in promoting the dense formation, transient stabilization, and timely turnover of NA within lamellipodia to couple actin-driven protrusion to adhesion and advance of the leading edge. Phosphorylation on Y397 of FAK promotes dense NA formation but is dispensable for transient NA stabilization and leading edge advance. In contrast, transient NA stabilization and advance of the cell edge requires FAK–Arp2/3 interaction, which promotes Arp2/3 localization to NA and reduces FAK activity. Haptosensing of extracellular matrix (ECM) concentration during migration requires the interaction between FAK and Arp2/3, whereas FAK phosphorylation modulates mechanosensing of ECM stiffness during spreading. Taken together, our results show that mechanistically separable functions of FAK in NA are required for cells to distinguish distinct properties of their environment during migration. PMID:26842895

ℋ-matrix techniques for approximating large covariance matrices and estimating its parameters

KAUST Repository

Litvinenko, Alexander; Genton, Marc G.; Sun, Ying; Keyes, David E.

2016-01-01

In this work the task is to use the available measurements to estimate unknown hyper-parameters (variance, smoothness parameter and covariance length) of the covariance function. We do it by maximizing the joint log-likelihood function. This is a non-convex and non-linear problem. To overcome cubic complexity in linear algebra, we approximate the discretised covariance function in the hierarchical (ℋ-) matrix format. The ℋ-matrix format has a log-linear computational cost and storage O(knlogn), where rank k is a small integer. On each iteration step of the optimization procedure the covariance matrix itself, its determinant and its Cholesky decomposition are recomputed within ℋ-matrix format. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

ℋ-matrix techniques for approximating large covariance matrices and estimating its parameters

KAUST Repository

Litvinenko, Alexander

2016-10-25

In this work the task is to use the available measurements to estimate unknown hyper-parameters (variance, smoothness parameter and covariance length) of the covariance function. We do it by maximizing the joint log-likelihood function. This is a non-convex and non-linear problem. To overcome cubic complexity in linear algebra, we approximate the discretised covariance function in the hierarchical (ℋ-) matrix format. The ℋ-matrix format has a log-linear computational cost and storage O(knlogn), where rank k is a small integer. On each iteration step of the optimization procedure the covariance matrix itself, its determinant and its Cholesky decomposition are recomputed within ℋ-matrix format. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Dynamic Compression Promotes the Matrix Synthesis of Nucleus Pulposus Cells Through Up-Regulating N-CDH Expression in a Perfusion Bioreactor Culture.

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Xu, Yichun; Yao, Hui; Li, Pei; Xu, Wenbin; Zhang, Junbin; Lv, Lulu; Teng, Haijun; Guo, Zhiliang; Zhao, Huiqing; Hou, Gang

2018-01-01

. This study provides a promising strategy to promote the matrix deposition of tissue-engineered NP tissue in vitro prior to clinical transplantation. © 2018 The Author(s). Published by S. Karger AG, Basel.

Transcriptional factor DLX3 promotes the gene expression of enamel matrix proteins during amelogenesis.

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Zhichun Zhang

Full Text Available Mutation of distal-less homeobox 3 (DLX3 is responsible for human tricho-dento-osseous syndrome (TDO with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.

The Exopolysaccharide Matrix

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Koo, H.; Falsetta, M.L.; Klein, M.I.

2013-01-01

Many infectious diseases in humans are caused or exacerbated by biofilms. Dental caries is a prime example of a biofilm-dependent disease, resulting from interactions of microorganisms, host factors, and diet (sugars), which modulate the dynamic formation of biofilms on tooth surfaces. All biofilms have a microbial-derived extracellular matrix as an essential constituent. The exopolysaccharides formed through interactions between sucrose- (and starch-) and Streptococcus mutans-derived exoenzymes present in the pellicle and on microbial surfaces (including non-mutans) provide binding sites for cariogenic and other organisms. The polymers formed in situ enmesh the microorganisms while forming a matrix facilitating the assembly of three-dimensional (3D) multicellular structures that encompass a series of microenvironments and are firmly attached to teeth. The metabolic activity of microbes embedded in this exopolysaccharide-rich and diffusion-limiting matrix leads to acidification of the milieu and, eventually, acid-dissolution of enamel. Here, we discuss recent advances concerning spatio-temporal development of the exopolysaccharide matrix and its essential role in the pathogenesis of dental caries. We focus on how the matrix serves as a 3D scaffold for biofilm assembly while creating spatial heterogeneities and low-pH microenvironments/niches. Further understanding on how the matrix modulates microbial activity and virulence expression could lead to new approaches to control cariogenic biofilms. PMID:24045647

Absorbable Suture as an Apical Matrix in Single Visit Apexification with Mineral Trioxide Aggregate

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Ayush Goyal

2016-01-01

Full Text Available Several procedures have been recommended to induce the root end barrier formation in teeth with open apices. Conventional treatment for such cases will require many appointments with an average duration of 12.9 months. During this period, the root canal is susceptible to reinfection from around the provisional restoration, which may promote apical periodontitis and arrest of apical repair. Mineral trioxide aggregate (MTA has been successfully used for one visit apexification wherein the root canal can be obturated within 24 hours after placement of MTA. Using a matrix prior to the placement of MTA avoids its extrusion, reduces leakage in the sealing material, and allows favorable response of the periapical tissues. This report presents a case of apexification where an absorbable suture was used as an apical matrix. Use of an absorbable suture circumvents all the problems associated with other conventional materials. Conclusion. Placement of the matrix made from the suture material is predictable and is easily positioned at the apex and the length can be adjusted as required. 10-month follow-up of the case shows resorbed matrix and bone healing in the periapical region. The patient was asymptomatic during the whole follow-up period and tooth exhibited mobility within physiologic limits and was functioning normally.

Absorbable Suture as an Apical Matrix in Single Visit Apexification with Mineral Trioxide Aggregate.

Science.gov (United States)

Goyal, Ayush; Nikhil, Vineeta; Jha, Padmanabh

2016-01-01

Several procedures have been recommended to induce the root end barrier formation in teeth with open apices. Conventional treatment for such cases will require many appointments with an average duration of 12.9 months. During this period, the root canal is susceptible to reinfection from around the provisional restoration, which may promote apical periodontitis and arrest of apical repair. Mineral trioxide aggregate (MTA) has been successfully used for one visit apexification wherein the root canal can be obturated within 24 hours after placement of MTA. Using a matrix prior to the placement of MTA avoids its extrusion, reduces leakage in the sealing material, and allows favorable response of the periapical tissues. This report presents a case of apexification where an absorbable suture was used as an apical matrix. Use of an absorbable suture circumvents all the problems associated with other conventional materials. Conclusion . Placement of the matrix made from the suture material is predictable and is easily positioned at the apex and the length can be adjusted as required. 10-month follow-up of the case shows resorbed matrix and bone healing in the periapical region. The patient was asymptomatic during the whole follow-up period and tooth exhibited mobility within physiologic limits and was functioning normally.

Oxidative stress specifically downregulates survivin to promote breast tumour formation.

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Pervin, S; Tran, L; Urman, R; Braga, M; Parveen, M; Li, S A; Chaudhuri, G; Singh, R

2013-03-05

Breast cancer, a heterogeneous disease has been broadly classified into oestrogen receptor positive (ER+) or oestrogen receptor negative (ER-) tumour types. Each of these tumours is dependent on specific signalling pathways for their progression. While high levels of survivin, an anti-apoptotic protein, increases aggressive behaviour in ER- breast tumours, oxidative stress (OS) promotes the progression of ER+ breast tumours. Mechanisms and molecular targets by which OS promotes tumourigenesis remain poorly understood. DETA-NONOate, a nitric oxide (NO)-donor induces OS in breast cancer cell lines by early re-localisation and downregulation of cellular survivin. Using in vivo models of HMLE(HRAS) xenografts and E2-induced breast tumours in ACI rats, we demonstrate that high OS downregulates survivin during initiation of tumourigenesis. Overexpression of survivin in HMLE(HRAS) cells led to a significant delay in tumour initiation and tumour volume in nude mice. This inverse relationship between survivin and OS was also observed in ER+ human breast tumours. We also demonstrate an upregulation of NADPH oxidase-1 (NOX1) and its activating protein p67, which are novel markers of OS in E2-induced tumours in ACI rats and as well as in ER+ human breast tumours. Our data, therefore, suggest that downregulation of survivin could be an important early event by which OS initiates breast tumour formation.

CAPN 7 promotes the migration and invasion of human endometrial stromal cell by regulating matrix metalloproteinase 2 activity.

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Liu, Hongyu; Jiang, Yue; Jin, Xiaoyan; Zhu, Lihua; Shen, Xiaoyue; Zhang, Qun; Wang, Bin; Wang, Junxia; Hu, Yali; Yan, Guijun; Sun, Haixiang

2013-07-15

Matrix metalloproteinase 2 (MMP-2) has been reported to be an important regulator of cell migration and invasion through degradation of the extracellular matrix (ECM) in many diseases, such as cancer and endometriosis. Here, we found calcium-activated neutral protease 7 (CAPN 7) expression was markedly upregulated in the eutopic endometrium and endometrial stromal cells of women diagnosed with endometriosis. Our studies were carried out to detect the effects of CAPN 7 on human endometrial stromal cell (hESC) migration and invasion. Western blotting and quantitative real-time PCR were used to detect the expression of CAPN 7 in endometriosis patients and normal fertile women. Scratch-wound-healing and invasion chamber assay were used to investigate the role of CAPN 7 in hESC migration and invasion. Western blotting, quantitative real-time PCR and zymography were carried out to detect the effect of CAPN 7 on the expressions and activity of MMP-2. CAPN 7 was markedly up-regulated in endometriosis, thereby promoting the migration and invasion of hESC. CAPN 7 overexpression led to increased expression of MMP-2 and tissue inhibitor of metalloproteinases 2 (TIMP-2); CAPN 7 knockdown reversed these changes. CAPN 7 increased MMP-2 activity by increasing the ratio of MMP-2 to TIMP-2. We also found that OA-Hy (an MMP-2 inhibitor) decreased the effects of CAPN 7 overexpression on hESC migration and invasion by approximately 50% and 55%, respectively. Additionally, a coimmunoprecipitation assay demonstrated that CAPN 7 interacted with activator protein 2α (AP-2α): an important transcription factor of MMP-2. CAPN 7 promotes hESC migration and invasion by increasing the activity of MMP-2 via an increased ratio of MMP-2 to TIMP-2.

Decreased Neointimal Extracellular Matrix Formation in RAGE-Knockout Mice After Microvascular Denudation

Energy Technology Data Exchange (ETDEWEB)

Groezinger, Gerd, E-mail: gerd.groezinger@med.uni-tuebingen.de; Schmehl, Joerg, E-mail: joerg.schmehl@med.uni-tuebingen.de; Bantleon, Ruediger, E-mail: ruediger.bantleon@med.uni-tuebingen.de; Kehlbach, Rainer, E-mail: rainer.kehlbach@uni-tuebingen.de [University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Mehra, Tarun, E-mail: tarun.mehra@med.uni-tuebingen.de [University of Tuebingen, Department of Dermatology (Germany); Claussen, Claus, E-mail: gerd.groezinger@med.uni-tuebingen.de; Wiesinger, Benjamin, E-mail: benjamin.wiesinger@med.uni-tuebingen.de [University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

2012-12-15

Purpose: To evaluate in vivo the role of RAGE (receptor for advanced glycated end products) in the development of restenosis and neointimal proliferation in RAGE-deficient knockout (KO) mice compared with wild-type (WT) mice in an animal model. Materials and Methods: Sixteen WT and 15 RAGE-deficient mice underwent microvascular denudation of the common femoral artery under general anaesthesia. Contralateral arteries underwent a sham operation and served as controls. Four weeks after the intervention, all animals were killed, and paraformaldehyde-fixed specimens of the femoral artery were analysed with different stains (hematoxylin and eosin and Elastica van Gieson) and several different types of immunostaining (proliferating cell nuclear antigen, {alpha}-actin, collagen, von Willebrand factor, RAGE). Luminal area, area of the neointima, and area of the media were measured in all specimens. In addition, colony-formation assays were performed, and collagen production by WT smooth muscle cells (SMCs) and RAGE-KO SMCs was determined. For statistical analysis, P < 0.05 was considered statistically significant. Results: Four weeks after denudation, WT mice showed a 49.6% loss of luminal area compared with 14.9% loss of luminal area in RAGE-deficient mice (sham = 0% loss) (P < 0.001). The neointima was 18.2 (*1000 {mu}m{sup 2} [n = 15) in the WT group compared with only 8.4 (*1000 {mu}m{sup 2} [n = 16]) in the RAGE-KO group. RAGE-KO SMCs showed significantly decreased proliferation activity and production of extracellular matrix protein. Conclusion: RAGE may be shown to play a considerable role in the formation of neointima leading to restenosis after vascular injury.

Microstructural study and densification analysis of hot work tool steel matrix composites reinforced with TiB{sub 2} particles

Energy Technology Data Exchange (ETDEWEB)

Fedrizzi, A., E-mail: anna.fedrizzi@ing.unitn.it [Department of Industrial Engineering, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Pellizzari, M. [Department of Industrial Engineering, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Zadra, M. [K4Sint, Start-up of the University of Trento, Viale Dante 300, 38057 Pergine Valsugana (Italy); Marin, E. [Department of Chemistry, Physics and Environment, University of Udine, Via Cotonificio 108, 33100 Udine (Italy)

2013-12-15

Hot work tool steels are characterized by good toughness and high hot hardness but are less wear resistant than other tooling materials, such as high speed steel. Metal matrix composites show improved tribological behavior, but not much work has been done in the field of hot work tool steels. In this paper TiB{sub 2}-reinforced hot work tool steel matrix composites were produced by spark plasma sintering (SPS). Mechanical alloying (MA) was proposed as a suited process to improve the composite microstructure. Density measurements and microstructure confirmed that MA promotes sintering and produces a fine and homogeneous dispersion of reinforcing particles. X-ray diffraction patterns of the sintered composites highlighted the formation of equilibrium Fe{sub 2}B and TiC, as predicted by thermodynamic calculations using Thermo-Calc® software. Scanning electron microscopy as well as scanning Kelvin probe force microscopy highlighted the reaction of the steel matrix with TiB{sub 2} particles, showing the formation of a reaction layer at the TiB{sub 2}-steel interface. Phase investigations pointed out that TiB{sub 2} is not chemically stable in steel matrix because of the presence of carbon even during short time SPS. - Highlights: • TiB{sub 2} reinforced steel matrix composites were produced by spark plasma sintering. • TiB{sub 2} was successfully dispersed in the steel matrix by mechanical alloying. • Steel and TiB{sub 2} react during sintering forming equilibrium Fe{sub 2}B and TiC. • The new phases were investigated by means of AFM, Volta potential and XRD analyses.

Matrix metalloproteinase-10 promotes tumor progression through regulation of angiogenic and apoptotic pathways in cervical tumors

International Nuclear Information System (INIS)

Zhang, Ge; Miyake, Makito; Lawton, Adrienne; Goodison, Steve; Rosser, Charles J

2014-01-01

Cancer invasion and metastasis develops through a series of steps that involve the loss of cell to cell and cell to matrix adhesion, degradation of extracellular matrix and induction of angiogenesis. Different protease systems (e.g., matrix metalloproteinases, MMPs) are involved in these steps. MMP-10, one of the lesser studied MMPs, is limited to epithelial cells and can facilitate tumor cell invasion by targeting collagen, elastin and laminin. Enhanced MMP-10 expression has been linked to poor clinical prognosis in some cancers, however, mechanisms underlying a role for MMP-10 in tumorigenesis and progression remain largely unknown. Here, we report that MMP-10 expression is positively correlated with the invasiveness of human cervical and bladder cancers. Using commercial tissue microarray (TMA) of cervical and bladder tissues, MMP-10 immunohistochemical staining was performed. Furthermore using a panel of human cells (HeLa and UROtsa), in vitro and in vivo experiments were performed in which MMP-10 was overexpressed or silenced and we noted phenotypic and genotypic changes. Experimentally, we showed that MMP-10 can regulate tumor cell migration and invasion, and endothelial cell tube formation, and that MMP-10 effects are associated with a resistance to apoptosis. Further investigation revealed that increasing MMP-10 expression stimulates the expression of HIF-1α and MMP-2 (pro-angiogenic factors) and PAI-1 and CXCR2 (pro-metastatic factors), and accordingly, targeting MMP-10 with siRNA in vivo resulted in diminution of xenograft tumor growth with a concomitant reduction of angiogenesis and a stimulation of apoptosis. Taken together, our findings show that MMP-10 can play a significant role in tumor growth and progression, and that MMP-10 perturbation may represent a rational strategy for cancer treatment

Phenylethanol promotes adhesion and biofilm formation of the antagonistic yeast Kloeckera apiculata for the control of blue mold on citrus.

Science.gov (United States)

Pu, Liu; Jingfan, Fang; Kai, Chen; Chao-an, Long; Yunjiang, Cheng

2014-06-01

The yeast Kloeckera apiculata strain 34-9 is an antagonist with biological control activity against postharvest diseases of citrus fruit. In a previous study it was demonstrated that K. apiculata produced the aromatic alcohol phenylethanol. In the present study, we found that K. apiculata was able to form biofilm on citrus fruit and embed in an extracellular matrix, which created a mechanical barrier interposed between the wound surface and pathogen. As a quorum-sensing molecule, phenylethanol can promote the formation of filaments by K. apiculata in potato dextrose agar medium, whereas on the citrus fruit, the antagonist remains as yeast after being treated with the same concentration of phenylethanol. It only induced K. apiculata to adhere and form biofilm. Following genome-wide computational and experimental identification of the possible genes associated with K. apiculata adhesion, we identified nine genes possibly involved in triggering yeast adhesion. Six of these genes were significantly induced after phenylethanol stress treatment. This study provides a new model system of the biology of the antagonist-pathogen interactions that occur in the antagonistic yeast K. apiculata for the control of blue mold on citrus caused by Penicillium italicum. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

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

2017-11-01

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 35:2506-2512, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Using quantitative magnetic resonance methods to understand better the gel-layer formation on polymer-matrix tablets.

Science.gov (United States)

Mikac, Urša; Kristl, Julijana; Baumgartner, Saša

2011-05-01

Magnetic resonance imaging is a powerful, non-invasive technique that can help improve our understanding of the hydrogel layer formed on swellable, polymer-matrix tablets, as well as the layer's properties and its influence on drug release. In this paper, the authors review the NMR and MRI investigations of hydrophilic, swellable polymers published since 1994. The review covers NMR studies on the properties of water and drugs within hydrated polymers. In addition, MRI studies using techniques for determining the different moving-front positions within the swollen tablets, the polymer concentration profiles across them, the influence of the incorporated drug, and so on, are presented. Some complementary methods are also briefly presented and discussed. Using MRI, the formation of a hydrogel along with simultaneous determination of the drug's position within it can be observed non-invasively. However, the MRI parameters can influence the signal's intensity and therefore they need to be considered carefully in order to prevent any misinterpretation of the results. MRI makes possible an in situ investigation of swollen-matrix tablets and provides valuable information that can lead, when combined with other techniques, to a better understanding of polymeric systems and a more effective development of optimal dosage forms.

Analysis of Invasion Dynamics of Matrix-Embedded Cells in a Multisample Format.

Science.gov (United States)

Van Troys, Marleen; Masuzzo, Paola; Huyck, Lynn; Bakkali, Karima; Waterschoot, Davy; Martens, Lennart; Ampe, Christophe

2018-01-01

In vitro tests of cancer cell invasion are the "first line" tools of preclinical researchers for screening the multitude of chemical compounds or cell perturbations that may aid in halting or treating cancer malignancy. In order to have predictive value or to contribute to designing personalized treatment regimes, these tests need to take into account the cancer cell environment and measure effects on invasion in sufficient detail. The in vitro invasion assays presented here are a trade-off between feasibility in a multisample format and mimicking the complexity of the tumor microenvironment. They allow testing multiple samples and conditions in parallel using 3D-matrix-embedded cells and deal with the heterogeneous behavior of an invading cell population in time. We describe the steps to take, the technical problems to tackle and useful software tools for the entire workflow: from the experimental setup to the quantification of the invasive capacity of the cells. The protocol is intended to guide researchers to standardize experimental set-ups and to annotate their invasion experiments in sufficient detail. In addition, it provides options for image processing and a solution for storage, visualization, quantitative analysis, and multisample comparison of acquired cell invasion data.

A single cysteine post-translational oxidation suffices to compromise globular proteins kinetic stability and promote amyloid formation

Directory of Open Access Journals (Sweden)

Patrizia Marinelli

2018-04-01

Full Text Available Oxidatively modified forms of proteins accumulate during aging. Oxidized protein conformers might act as intermediates in the formation of amyloids in age-related disorders. However, it is not known whether this amyloidogenic conversion requires an extensive protein oxidative damage or it can be promoted just by a discrete, localized post-translational modification of certain residues. Here, we demonstrate that the irreversible oxidation of a single free Cys suffices to severely perturb the folding energy landscape of a stable globular protein, compromise its kinetic stability, and lead to the formation of amyloids under physiological conditions. Experiments and simulations converge to indicate that this specific oxidation-promoted protein aggregation requires only local unfolding. Indeed, a large scale analysis indicates that many cellular proteins are at risk of undergoing this kind of deleterious transition; explaining how oxidative stress can impact cell proteostasis and subsequently lead to the onset of pathological states. Keywords: Protein oxidation, Protein misfolding, Protein aggregation, Oxidative stress, Post-translational modification

Machining of Metal Matrix Composites

CERN Document Server

2012-01-01

Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

Impact of flavonoids on matrix metalloproteinase secretion and invadopodia formation in highly invasive A431-III cancer cells.

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Yo-Chuen Lin

Full Text Available Metastasis is a major cause of mortality in cancer patients. Invadopodia are considered to be crucial structures that allow cancer cells to penetrate across the extracellular matrix (ECM by using matrix metalloproteinases (MMPs. Previously, we isolated a highly invasive A431-III subline from parental A431 cells by Boyden chamber assay. The A431-III cells possess higher invasive and migratory abilities, elevated levels of MMP-9 and an enhanced epithelial-mesenchymal transition (EMT phenotype. In this study, we discovered that A431-III cells had an increased potential to form invadopodia and an improved capacity to degrade ECM compared with the original A431 cells. We also observed enhanced phosphorylation levels of cortactin and Src in A431-III cells; these phosphorylated proteins have been reported to be the main regulators of invadopodia formation. Flavonoids, almost ubiquitously distributed in food plants and plant food products, have been documented to exhibit anti-tumor properties. Therefore, it was of much interest to explore the effects of flavonoid antioxidants on the metastatic activity of A431-III cells. Exposure of A431-III cells to two potent dietary flavonoids, namely luteolin (Lu and quercetin (Qu, caused inhibition of invadopodia formation and decrement in ECM degradation. We conclude that Lu and Qu attenuate the phosphorylation of cortactin and Src in A431-III cells. As a consequence, there ensues a disruption of invadopodia generation and the suppression of MMP secretion. These changes, in concert, bring about a reduction in metastasis.

Proteoliposomes as matrix vesicles' biomimetics to study the initiation of skeletal mineralization

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A.M.S. Simão

2010-03-01

Full Text Available During the process of endochondral bone formation, chondrocytes and osteoblasts mineralize their extracellular matrix by promoting the formation of hydroxyapatite (HA seed crystals in the sheltered interior of membrane-limited matrix vesicles (MVs. Ion transporters control the availability of phosphate and calcium needed for HA deposition. The lipidic microenvironment in which MV-associated enzymes and transporters function plays a crucial physiological role and must be taken into account when attempting to elucidate their interplay during the initiation of biomineralization. In this short mini-review, we discuss the potential use of proteoliposome systems as chondrocyte- and osteoblast-derived MVs biomimetics, as a means of reconstituting a phospholipid microenvironment in a manner that recapitulates the native functional MV microenvironment. Such a system can be used to elucidate the interplay of MV enzymes during catalysis of biomineralization substrates and in modulating in vitro calcification. As such, the enzymatic defects associated with disease-causing mutations in MV enzymes could be studied in an artificial vesicular environment that better mimics their in vivo biological milieu. These artificial systems could also be used for the screening of small molecule compounds able to modulate the activity of MV enzymes for potential therapeutic uses. Such a nanovesicular system could also prove useful for the repair/treatment of craniofacial and other skeletal defects and to facilitate the mineralization of titanium-based tooth implants.

Stress relaxing hyaluronic acid-collagen hydrogels promote cell spreading, fiber remodeling, and focal adhesion formation in 3D cell culture.

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Lou, Junzhe; Stowers, Ryan; Nam, Sungmin; Xia, Yan; Chaudhuri, Ovijit

2018-02-01

The physical and architectural cues of the extracellular matrix (ECM) play a critical role in regulating important cellular functions such as spreading, migration, proliferation, and differentiation. Natural ECM is a complex viscoelastic scaffold composed of various distinct components that are often organized into a fibrillar microstructure. Hydrogels are frequently used as synthetic ECMs for 3D cell culture, but are typically elastic, due to covalent crosslinking, and non-fibrillar. Recent work has revealed the importance of stress relaxation in viscoelastic hydrogels in regulating biological processes such as spreading and differentiation, but these studies all utilize synthetic ECM hydrogels that are non-fibrillar. Key mechanotransduction events, such as focal adhesion formation, have only been observed in fibrillar networks in 3D culture to date. Here we present an interpenetrating network (IPN) hydrogel system based on HA crosslinked with dynamic covalent bonds and collagen I that captures the viscoelasticity and fibrillarity of ECM in tissues. The IPN hydrogels exhibit two distinct processes in stress relaxation, one from collagen and the other from HA crosslinking dynamics. Stress relaxation in the IPN hydrogels can be tuned by modulating HA crosslinker affinity, molecular weight of the HA, or HA concentration. Faster relaxation in the IPN hydrogels promotes cell spreading, fiber remodeling, and focal adhesion (FA) formation - behaviors often inhibited in other hydrogel-based materials in 3D culture. This study presents a new, broadly adaptable materials platform for mimicking key ECM features of viscoelasticity and fibrillarity in hydrogels for 3D cell culture and sheds light on how these mechanical and structural cues regulate cell behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

IL-33 activates tumor stroma to promote intestinal polyposis.

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Maywald, Rebecca L; Doerner, Stephanie K; Pastorelli, Luca; De Salvo, Carlo; Benton, Susan M; Dawson, Emily P; Lanza, Denise G; Berger, Nathan A; Markowitz, Sanford D; Lenz, Heinz-Josef; Nadeau, Joseph H; Pizarro, Theresa T; Heaney, Jason D

2015-05-12

Tumor epithelial cells develop within a microenvironment consisting of extracellular matrix, growth factors, and cytokines produced by nonepithelial stromal cells. In response to paracrine signals from tumor epithelia, stromal cells modify the microenvironment to promote tumor growth and metastasis. Here, we identify interleukin 33 (IL-33) as a regulator of tumor stromal cell activation and mediator of intestinal polyposis. In human colorectal cancer, IL-33 expression was induced in the tumor epithelium of adenomas and carcinomas, and expression of the IL-33 receptor, IL1RL1 (also referred to as IL1-R4 or ST2), localized predominantly to the stroma of adenoma and both the stroma and epithelium of carcinoma. Genetic and antibody abrogation of responsiveness to IL-33 in the Apc(Min/+) mouse model of intestinal tumorigenesis inhibited proliferation, induced apoptosis, and suppressed angiogenesis in adenomatous polyps, which reduced both tumor number and size. Similar to human adenomas, IL-33 expression localized to tumor epithelial cells and expression of IL1RL1 associated with two stromal cell types, subepithelial myofibroblasts and mast cells, in Apc(Min/+) polyps. In vitro, IL-33 stimulation of human subepithelial myofibroblasts induced the expression of extracellular matrix components and growth factors associated with intestinal tumor progression. IL-33 deficiency reduced mast cell accumulation in Apc(Min/+) polyps and suppressed the expression of mast cell-derived proteases and cytokines known to promote polyposis. Based on these findings, we propose that IL-33 derived from the tumor epithelium promotes polyposis through the coordinated activation of stromal cells and the formation of a protumorigenic microenvironment.

Preparation of nickel-coated titanium carbide particulates and their use in the production of reinforced iron matrix composites

International Nuclear Information System (INIS)

Yi, Danqing; Yu, Pengchao; Hu, Bin; Liu, Huiqun; Wang, Bin; Jiang, Yong

2013-01-01

Highlights: • Ni-coated TiC composite powders were prepared by electroless plating. • Iron-based composites reinforced by TiC particles was prepared by HIP. • Mechanical and wear properties were improved with the addition of Ni-coated TiC. • The nickel coating promotes the formation and growth of sintering neck. - Abstract: Ni-coated titanium carbide (TiC) composite powders were prepared by electroless plating (EP). Further, using hot isostatic pressing (HIP), iron matrix composites reinforced with 4 wt% Ni-coated TiC particulates with relative density close to 100% were prepared. The microstructure and phase composition of the Ni-coated powders and the composites were analyzed using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results showed that the TiC particles were distributed uniformly in the matrix and were free of segregation or coarsening. Compared to the TiC particles without Ni coating, the reinforced iron-based composites containing the Ni-coated particles showed higher relative densities and better mechanical properties. The density, hardness, tensile strength, and elongation were enhanced to 99.98%, 243 HV, 565 MPa, and 11.7%, respectively in composites containing Ni-coated TiC particles from 99.70%, 210 HV, 514 MPa, and 10.3%, respectively in composites that were prepared using particles without Ni coating. In addition, the mass losses in the composites containing the Ni-coated particles were reduced by 32–75% in the abrasive wear test with various vertical loads. We propose that the nickel coatings on the particulates had a beneficial effect on the microstructure and properties of the reinforced iron-based composites is due to promotion of neck formation and growth between TiC and iron powders during sintering, which enhanced the density of the sintered compact and the bonding strength between the TiC particles and the iron matrix

An Exploration of Teachers' Narratives: What Are the Facilitators and Constraints Which Promote or Inhibit "Good" Formative Assessment Practices in Schools?

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Sach, Elizabeth

2015-01-01

This paper set out to explore teachers' narratives in order to understand some of the facilitators and constraints which promote or inhibit good formative assessment practices in schools. A "responsive interview" approach was used to probe a small sample of lower and middle school teachers' perceptions of formative assessment.…

Self-Assembled Matrix by Umbilical Cord Stem Cells

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Biagio Saitta

2011-09-01

Full Text Available Corneal integrity is critical for vision. Corneal wounds frequently heal with scarring that impairs vision. Recently, human umbilical cord mesenchymal stem cells (cord stem cells have been investigated for tissue engineering and therapy due to their availability and differentiation potential. In this study, we used cord stem cells in a 3-dimensional (3D stroma-like model to observe extracellular matrix organization, with human corneal fibroblasts acting as a control. For 4 weeks, the cells were stimulated with a stable Vitamin C (VitC derivative ±TGF-b1. After 4 weeks, the mean thickness of the constructs was ~30 mm; however, cord stem cell constructs had 50% less cells per unit volume, indicating the formation of a dense matrix. We found minimal change in decorin and lumican mRNA, and a significant increase in perlecan mRNA in the presence of TGF-b1. Keratocan on the other hand decreased with TGF-b1 in both cell lineages. With both cell types, the constructs possessed aligned collagen fibrils and associated glycosaminoglycans. Fibril diameters did not change with TGF-b1 stimulation or cell lineage; however, highly sulfated glycosaminoglycans associated with the collagen fibrils significantly increased with TGF-b1. Overall, we have shown that cord stem cells can secrete their own extracellular matrix and promote the deposition and sulfation of various proteoglycans. Furthermore, these cells are at least comparable to commonly used corneal fibroblasts and present an alternative for the 3D in vitro tissue engineered model.

Support vector regression-guided unravelling: antioxidant capacity and quantitative structure-activity relationship predict reduction and promotion effects of flavonoids on acrylamide formation

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Huang, Mengmeng; Wei, Yan; Wang, Jun; Zhang, Yu

2016-09-01

We used the support vector regression (SVR) approach to predict and unravel reduction/promotion effect of characteristic flavonoids on the acrylamide formation under a low-moisture Maillard reaction system. Results demonstrated the reduction/promotion effects by flavonoids at addition levels of 1-10000 μmol/L. The maximal inhibition rates (51.7%, 68.8% and 26.1%) and promote rates (57.7%, 178.8% and 27.5%) caused by flavones, flavonols and isoflavones were observed at addition levels of 100 μmol/L and 10000 μmol/L, respectively. The reduction/promotion effects were closely related to the change of trolox equivalent antioxidant capacity (ΔTEAC) and well predicted by triple ΔTEAC measurements via SVR models (R: 0.633-0.900). Flavonols exhibit stronger effects on the acrylamide formation than flavones and isoflavones as well as their O-glycosides derivatives, which may be attributed to the number and position of phenolic and 3-enolic hydroxyls. The reduction/promotion effects were well predicted by using optimized quantitative structure-activity relationship (QSAR) descriptors and SVR models (R: 0.926-0.994). Compared to artificial neural network and multi-linear regression models, SVR models exhibited better fitting performance for both TEAC-dependent and QSAR descriptor-dependent predicting work. These observations demonstrated that the SVR models are competent for predicting our understanding on the future use of natural antioxidants for decreasing the acrylamide formation.

Effect of Human Serum and 2 Different Types of Platelet Concentrates on Human Meniscus Cell Migration, Proliferation, and Matrix Formation.

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Freymann, Undine; Metzlaff, Sebastian; Krüger, Jan-Philipp; Hirsh, Glen; Endres, Michaela; Petersen, Wolf; Kaps, Christian

2016-06-01

To evaluate the effect of 10% human serum (HS), 5% platelet-rich plasma (PRP), and 5% autologous conditioned plasma (ACP) on migration, proliferation, and extracellular matrix (ECM) synthesis of human meniscus cells. Cell migration and proliferation on stimulation with HS, PRP, and ACP were assessed by chemotaxis assays and measurement of genomic DNA content. Meniscus cells were cultivated in pellets stimulated with 10% HS, 5% PRP, or 5% ACP. Meniscal ECM formation was evaluated by histochemical staining of collagen type I, type II, and proteoglycans and by analysis of fibrochondrocyte marker gene expression. Human meniscus cells were significantly attracted by all 3 blood-derived products (10% HS and 5% ACP: P = .0001, 5% PRP: P = .0002). Cell proliferation at day 9 was significantly increased on stimulation with 10% HS (P = .0001) and 5% PRP (P = .0002) compared with 5% ACP and controls. Meniscus cell pellet cultures showed the formation of a well-structured meniscal ECM with deposition of collagen type I, type II, and proteoglycans on stimulation with 10% HS, whereas 5% PRP or 5% ACP resulted in the formation of an inhomogeneous and more fibrous ECM. Stimulation with 10% HS and 5% ACP showed a significant induction of fibrochondrocyte marker genes such as aggrecan (HS: P = .0002, ACP: P = .0147), cartilage oligomeric matrix protein (HS: P = .0002, ACP: P = .0005), and biglycan (HS: P = .0002, ACP: P = .0003), whereas PRP showed no inducing effect. Among all tested blood-derived products, only stimulation with HS showed the formation of a meniscal ECM as well as positive cell proliferating and migrating effects in vitro. Regarding a potential biological repair of nonvascular meniscus lesions, our results may point toward the use of HS as a beneficial augment in regenerative meniscus repair approaches. Our findings may suggest that HS might be a beneficial augment for meniscus repair. Copyright © 2016 Arthroscopy Association of North America. Published

Membrane-type-3 matrix metalloproteinase (MT3-MMP functions as a matrix composition-dependent effector of melanoma cell invasion.

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Olga Tatti

Full Text Available In primary human melanoma, the membrane-type matrix metalloproteinase, MT3-MMP, is overexpressed in the most aggressive nodular-type tumors. Unlike MT1-MMP and MT2-MMP, which promote cell invasion through basement membranes and collagen type I-rich tissues, the function of MT3-MMP in tumor progression remains unclear. Here, we demonstrate that MT3-MMP inhibits MT1-MMP-driven melanoma cell invasion in three-dimensional collagen, while yielding an altered, yet MT1-MMP-dependent, form of expansive growth behavior that phenocopies the formation of nodular cell colonies. In melanoma cell lines originating from advanced primary or metastatic lesions, endogenous MT3-MMP expression was associated with limited collagen-invasive potential. In the cell lines with highest MT3-MMP expression relative to MT1-MMP, collagen-invasive activity was increased following stable MT3-MMP gene silencing. Consistently, MT3-MMP overexpression in cells derived from less advanced superficially spreading melanoma lesions, or in the MT3-MMP knockdown cells, reduced MT1-MMP-dependent collagen invasion. Rather than altering MT1-MMP transcription, MT3-MMP interacted with MT1-MMP in membrane complexes and reduced its cell surface expression. By contrast, as a potent fibrinolytic enzyme, MT3-MMP induced efficient invasion of the cells in fibrin, a provisional matrix component frequently found at tumor-host tissue interfaces and perivascular spaces of melanoma. Since MT3-MMP was significantly upregulated in biopsies of human melanoma metastases, these results identify MT3-MMP as a matrix-dependent modifier of the invasive tumor cell functions during melanoma progression.

Detachment-induced E-cadherin expression promotes 3D tumor spheroid formation but inhibits tumor formation and metastasis of lung cancer cells.

Science.gov (United States)

Powan, Phattrakorn; Luanpitpong, Sudjit; He, Xiaoqing; Rojanasakul, Yon; Chanvorachote, Pithi

2017-11-01

The epithelial-to-mesenchymal transition is proposed to be a key mechanism responsible for metastasis-related deaths. Similarly, cancer stem cells (CSCs) have been proposed to be a key driver of tumor metastasis. However, the link between the two events and their control mechanisms is unclear. We used a three-dimensional (3D) tumor spheroid assay and other CSC-indicating assays to investigate the role of E-cadherin in CSC regulation and its association to epithelial-to-mesenchymal transition in lung cancer cells. Ectopic overexpression and knockdown of E-cadherin were found to promote and retard, respectively, the formation of tumor spheroids in vitro but had opposite effects on tumor formation and metastasis in vivo in a xenograft mouse model. We explored the discrepancy between the in vitro and in vivo results and demonstrated, for the first time, that E-cadherin is required as a component of a major survival pathway under detachment conditions. Downregulation of E-cadherin increased the stemness of lung cancer cells but had an adverse effect on their survival, particularly on non-CSCs. Such downregulation also promoted anoikis resistance and invasiveness of lung cancer cells. These results suggest that anoikis assay could be used as an alternative method for in vitro assessment of CSCs that involves dysregulated adhesion proteins. Our data also suggest that agents that restore E-cadherin expression may be used as therapeutic agents for metastatic cancers. Copyright © 2017 the American Physiological Society.

Inter-organizational relationships: promoters and restrictive factors in the formation of cooperation network

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Marcos Antonio Gaspar

2014-04-01

Full Text Available The present paper had as aim to identify factors of inter-organizational relationships which promotes and restricts the formation of companies’ cooperation network, from two levels of analysis (organizational and inter-organizational. To achieve this goal, it was developed a descriptive-qualitative study, with prospecting for primary and secondary data on a cooperation network. The universe was composed by 41 participating companies associated to the analyzed network. The sampling procedure was for researcher’s accessibility and convenience. As a result, it was identified that the network is guided by goals of cooperation among the participating companies, in addition to representing the sector and provide services in the interests of the associates. The main factors influencing the formation of the network were: business center, marketing and training; but only training has been achieved satisfactorily. The business center and marketing factors have not yet been fully developed, being both identified as restrictive factors.

Liarozole inhibits transforming growth factor-β3–mediated extracellular matrix formation in human three-dimensional leiomyoma cultures

Science.gov (United States)

Levy, Gary; Malik, Minnie; Britten, Joy; Gilden, Melissa; Segars, James; Catherino, William H.

2014-01-01

Objective To investigate the impact of liarozole on transforming growth factor-β3 (TGF-β3) expression, TGF-β3 controlled profibrotic cytokines, and extracellular matrix formation in a three-dimensional (3D) leiomyoma model system. Design Molecular and immunohistochemical analysis in a cell line evaluated in a three-dimensional culture. Setting Laboratory study. Patient(s) None. Intervention(s) Treatment of leiomyoma and myometrial cells with liarozole and TGF-β3 in a three-dimensional culture system. Main Outcome Measure(s) Quantitative real-time reverse-transcriptase polymerase chain reaction and Western blotting to assess fold gene and protein expression of TGF-β3 and TGF-β3 regulated fibrotic cytokines: collagen 1A1 (COL1A1), fibronectin, and versican before and after treatment with liarozole, and confirmatory immunohistochemical stains of treated three-dimensional cultures. Result(s) Both TGF-β3 gene and protein expression were elevated in leiomyoma cells compared with myometrium in two-dimensional and 3D cultures. Treatment with liarozole decreased TGF-β3 gene and protein expression. Extracellular matrix components versican, COL1A1, and fibronectin were also decreased by liarozole treatment in 3D cultures. Treatment of 3D cultures with TGF-β3 increased gene expression and protein production of COL1A1, fibronectin, and versican. Conclusion(s) Liarozole decreased TGF-β3 and TGF-β3–mediated extracellular matrix expression in a 3D uterine leiomyoma culture system. PMID:24825427

Osteoblasts extracellular matrix induces vessel like structures through glycosylated collagen I

Energy Technology Data Exchange (ETDEWEB)

Palmieri, D. [Genetics, DIBIO, University of Genova, Corso Europa 26, 16132 Genova (Italy); Valli, M.; Viglio, S. [Department of Biochemistry, University of Pavia (Italy); Ferrari, N. [Istituto Nazionale per la ricerca sul Cancro, Genova (Italy); Ledda, B.; Volta, C. [Genetics, DIBIO, University of Genova, Corso Europa 26, 16132 Genova (Italy); Manduca, P., E-mail: man-via@unige.it [Genetics, DIBIO, University of Genova, Corso Europa 26, 16132 Genova (Italy)

2010-03-10

Extracellular matrix (ECM) plays a fundamental role in angiogenesis affecting endothelial cells proliferation, migration and differentiation. Vessels-like network formation in vitro is a reliable test to study the inductive effects of ECM on angiogenesis. Here we utilized matrix deposed by osteoblasts as substrate where the molecular and structural complexity of the endogenous ECM is preserved, to test if it induces vessel-like network formation by endothelial cells in vitro. ECM is more similar to the physiological substrate in vivo than other substrates previously utilized for these studies in vitro. Osteogenic ECM, prepared in vitro from mature osteoblasts at the phase of maximal deposition and glycosylation of collagen I, induces EAhy926, HUVEC, and HDMEC endothelial cells to form vessels-like structures and promotes the activation of metalloproteinase-2 (MMP-2); the functionality of the p-38/MAPK signaling pathway is required. Osteogenic ECM also induces a transient increase of CXCL12 and a decrease of the receptor CXCR4. The induction of vessel-like networks is dependent from proper glycosylation of collagens and does not occur on osteogenic ECMs if deglycosylated by -galactosidase or on less glycosylated ECMs derived from preosteoblasts and normal fibroblasts, while is sustained on ECM from osteogenesis imperfecta fibroblasts only when their mutation is associated with over-glycosylation of collagen type I. These data support that post-translational glycosylation has a role in the induction in endothelial cells in vitro of molecules conductive to self-organization in vessels-like structures.

Osteoblasts extracellular matrix induces vessel like structures through glycosylated collagen I

International Nuclear Information System (INIS)

Palmieri, D.; Valli, M.; Viglio, S.; Ferrari, N.; Ledda, B.; Volta, C.; Manduca, P.

2010-01-01

Extracellular matrix (ECM) plays a fundamental role in angiogenesis affecting endothelial cells proliferation, migration and differentiation. Vessels-like network formation in vitro is a reliable test to study the inductive effects of ECM on angiogenesis. Here we utilized matrix deposed by osteoblasts as substrate where the molecular and structural complexity of the endogenous ECM is preserved, to test if it induces vessel-like network formation by endothelial cells in vitro. ECM is more similar to the physiological substrate in vivo than other substrates previously utilized for these studies in vitro. Osteogenic ECM, prepared in vitro from mature osteoblasts at the phase of maximal deposition and glycosylation of collagen I, induces EAhy926, HUVEC, and HDMEC endothelial cells to form vessels-like structures and promotes the activation of metalloproteinase-2 (MMP-2); the functionality of the p-38/MAPK signaling pathway is required. Osteogenic ECM also induces a transient increase of CXCL12 and a decrease of the receptor CXCR4. The induction of vessel-like networks is dependent from proper glycosylation of collagens and does not occur on osteogenic ECMs if deglycosylated by -galactosidase or on less glycosylated ECMs derived from preosteoblasts and normal fibroblasts, while is sustained on ECM from osteogenesis imperfecta fibroblasts only when their mutation is associated with over-glycosylation of collagen type I. These data support that post-translational glycosylation has a role in the induction in endothelial cells in vitro of molecules conductive to self-organization in vessels-like structures.

Improvement of characteristics of diffraction gratings in Dot-matrix holograms

International Nuclear Information System (INIS)

ZHUMALIEV, K.M.; ISMAILOV, D.A.; ZHEENBEKOV, A.A.; SARYBAEVA, A.A.; KAZAKBAEVA, Z.M.

2014-01-01

This paper describes the results of research of the formation and recording of matrix hologram by Dot-matrix (dot-matrix hologram) technology on the photosensitive material of the photoresist. The principle of creating and modifying the characteristics of diffraction gratings of each pixel based on the diffraction efficiency, and recovery of colors and dynamic visual effects in dot-matrix holograms are discussed. An optical schematic diagram of the device and the process of recording dot-matrix holograms are presented. (authors)

Subinhibitory concentrations of triclosan promote Streptococcus mutans biofilm formation and adherence to oral epithelial cells.

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Telma Blanca Lombardo Bedran

Full Text Available Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at sub-MICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that sub-MICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since sub-MICs may promote colonization of the oral cavity by S. mutans.

Cisplatin upregulates mitochondrial nitric oxide synthase and peroxynitrite formation to promote renal injury

International Nuclear Information System (INIS)

Jung, Michaela; Hotter, Georgina; Vinas, Jose Luis; Sola, Anna

2009-01-01

The mitochondria are a critical target for cisplatin-associated nephrotoxicity. Though nitric oxide formation has been implicated in the toxicity of cisplatin, this formation has not so far been related to a possible activation of mitochondrial nitric oxide synthase (mNOS). We show here that the upregulation of oxide mNOS and peroxynitrite formation in cisplatin treatment are key events that influence the development of the harmful parameters described in cisplatin-associated kidney failure. We confirm this by isolating the mitochondrial fraction of the kidney and across different access routes such as the use of a specific inhibitor of neuronal NOS, L-NPA, a peroxynitrite scavenger, FeTMPyP, and a peroxynitrite donor, SIN-1. The in vitro studies corroborated the information obtained in the in vivo experiments. The administration of cisplatin reveals a clear upregulation in the transcription of neuronal NOS and an increase in the levels of nitrites in the mitochondrial fractions of the kidneys. The upregulated transcription directly affects the cytoskeleton structure and the apoptosis. The inhibition of neuronal NOS reduces the levels of nitrites, cell death, and cytoskeleton derangement. Peroxynitrite is involved in the mechanism promoting the NOS transcription. In addition, in controls SIN-1 imitates the effects of cisplatin. In summary, we demonstrate that upregulation of mNOS in cisplatin treatment is a key component in both the initiation and the spread of cisplatin-associated damage in the kidney. Furthermore, peroxynitrite formation is directly involved in this process

Silicon-Doped Titanium Dioxide Nanotubes Promoted Bone Formation on Titanium Implants.

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Zhao, Xijiang; Wang, Tao; Qian, Shi; Liu, Xuanyong; Sun, Junying; Li, Bin

2016-02-26

While titanium (Ti) implants have been extensively used in orthopaedic and dental applications, the intrinsic bioinertness of untreated Ti surface usually results in insufficient osseointegration irrespective of the excellent biocompatibility and mechanical properties of it. In this study, we prepared surface modified Ti substrates in which silicon (Si) was doped into the titanium dioxide (TiO₂) nanotubes on Ti surface using plasma immersion ion implantation (PIII) technology. Compared to TiO₂ nanotubes and Ti alone, Si-doped TiO₂ nanotubes significantly enhanced the expression of genes related to osteogenic differentiation, including Col-I, ALP, Runx2, OCN, and OPN, in mouse pre-osteoblastic MC3T3-E1 cells and deposition of mineral matrix. In vivo, the pull-out mechanical tests after two weeks of implantation in rat femur showed that Si-doped TiO₂ nanotubes improved implant fixation strength by 18% and 54% compared to TiO₂-NT and Ti implants, respectively. Together, findings from this study indicate that Si-doped TiO₂ nanotubes promoted the osteogenic differentiation of osteoblastic cells and improved bone-Ti integration. Therefore, they may have considerable potential for the bioactive surface modification of Ti implants.

Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

Science.gov (United States)

Linsheng, Li; Guoxiang, Lin; Lihui, Li

2016-08-12

In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity.

Mifepristone inhibits extracellular matrix formation in uterine leiomyoma.

Science.gov (United States)

Patel, Amrita; Malik, Minnie; Britten, Joy; Cox, Jeris; Catherino, William H

2016-04-01

To characterize the efficacy of mifepristone treatment on extracellular matrix (ECM) production in leiomyomas. Laboratory study. University research laboratory. None. Treatment of human immortalized two-dimensional (2D) and three-dimensional (3D) leiomyoma and myometrial cells with mifepristone and the progestin promegestone (R5020). Expression of COL1A1, fibronectin, versican variant V0, and dermatopontin in treated leiomyoma cells by Western blot analysis and confirmatory immunohistochemistry staining of treated 3D cultures. Treatment with progestin stimulated production of COL1A1, fibronectin, versican, and dermatopontin. Mifepristone treatment inhibited protein production of these genes, most notably with versican expression. Combination treatment with both the agonist and antagonist further inhibited protein expression of these genes. Immunohistochemistry performed on 3D cultures demonstrated generalized inhibition of ECM protein concentration. Our study demonstrated that the progesterone agonist R5020 directly stimulated extracellular matrix components COL1A1, fibronectin, versican, and dermatopontin production in human leiomyoma cells. Progesterone antagonist mifepristone decreased protein production of these genes to levels comparable with untreated leiomyoma cells. Published by Elsevier Inc.

A Peptide Derived from the HIV-1 gp120 Coreceptor-Binding Region Promotes Formation of PAP248-286 Amyloid Fibrils to Enhance HIV-1 Infection.

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Jinquan Chen

Full Text Available Semen is a major vehicle for HIV transmission. Prostatic acid phosphatase (PAP fragments, such as PAP248-286, in human semen can form amyloid fibrils to enhance HIV infection. Other endogenous or exogenous factors present during sexual intercourse have also been reported to promote the formation of seminal amyloid fibrils.Here, we demonstrated that a synthetic 15-residue peptide derived from the HIV-1 gp120 coreceptor-binding region, designated enhancing peptide 2 (EP2, can rapidly self-assemble into nanofibers. These EP2-derivated nanofibers promptly accelerated the formation of semen amyloid fibrils by PAP248-286, as shown by Thioflavin T (ThT and Congo red assays. The amyloid fibrils presented similar morphology, assessed via transmission electron microscopy (TEM, in the presence or absence of EP2. Circular dichroism (CD spectroscopy revealed that EP2 accelerates PAP248-286 amyloid fibril formation by promoting the structural transition of PAP248-286 from a random coil into a cross-β-sheet. Newly formed semen amyloid fibrils effectively enhanced HIV-1 infection in TZM-bl cells and U87 cells by promoting the binding of HIV-1 virions to target cells.Nanofibers composed of EP2 promote the formation of PAP248-286 amyloid fibrils and enhance HIV-1 infection.

FAP-overexpressing fibroblasts produce an extracellular matrix that enhances invasive velocity and directionality of pancreatic cancer cells

International Nuclear Information System (INIS)

Lee, Hyung-Ok; Mullins, Stefanie R; Franco-Barraza, Janusz; Valianou, Matthildi; Cukierman, Edna; Cheng, Jonathan D

2011-01-01

Alterations towards a permissive stromal microenvironment provide important cues for tumor growth, invasion, and metastasis. In this study, Fibroblast activation protein (FAP), a serine protease selectively produced by tumor-associated fibroblasts in over 90% of epithelial tumors, was used as a platform for studying tumor-stromal interactions. We tested the hypothesis that FAP enzymatic activity locally modifies stromal ECM (extracellular matrix) components thus facilitating the formation of a permissive microenvironment promoting tumor invasion in human pancreatic cancer. We generated a tetracycline-inducible FAP overexpressing fibroblastic cell line to synthesize an in vivo-like 3-dimensional (3D) matrix system which was utilized as a stromal landscape for studying matrix-induced cancer cell behaviors. A FAP-dependent topographical and compositional alteration of the ECM was characterized by measuring the relative orientation angles of fibronectin fibers and by Western blot analyses. The role of FAP in the matrix-induced permissive tumor behavior was assessed in Panc-1 cells in assorted matrices by time-lapse acquisition assays. Also, FAP + matrix-induced regulatory molecules in cancer cells were determined by Western blot analyses. We observed that FAP remodels the ECM through modulating protein levels, as well as through increasing levels of fibronectin and collagen fiber organization. FAP-dependent architectural/compositional alterations of the ECM promote tumor invasion along characteristic parallel fiber orientations, as demonstrated by enhanced directionality and velocity of pancreatic cancer cells on FAP + matrices. This phenotype can be reversed by inhibition of FAP enzymatic activity during matrix production resulting in the disorganization of the ECM and impeded tumor invasion. We also report that the FAP + matrix-induced tumor invasion phenotype is β 1 -integrin/FAK mediated. Cancer cell invasiveness can be affected by alterations in the tumor

Extracellular-matrix-mediated osmotic pressure drives Vibrio cholerae biofilm expansion and cheater exclusion.

Science.gov (United States)

Yan, Jing; Nadell, Carey D; Stone, Howard A; Wingreen, Ned S; Bassler, Bonnie L

2017-08-23

Biofilms, surface-attached communities of bacteria encased in an extracellular matrix, are a major mode of bacterial life. How the material properties of the matrix contribute to biofilm growth and robustness is largely unexplored, in particular in response to environmental perturbations such as changes in osmotic pressure. Here, using Vibrio cholerae as our model organism, we show that during active cell growth, matrix production enables biofilm-dwelling bacterial cells to establish an osmotic pressure difference between the biofilm and the external environment. This pressure difference promotes biofilm expansion on nutritious surfaces by physically swelling the colony, which enhances nutrient uptake, and enables matrix-producing cells to outcompete non-matrix-producing cheaters via physical exclusion. Osmotic pressure together with crosslinking of the matrix also controls the growth of submerged biofilms and their susceptibility to invasion by planktonic cells. As the basic physicochemical principles of matrix crosslinking and osmotic swelling are universal, our findings may have implications for other biofilm-forming bacterial species.Most bacteria live in biofilms, surface-attached communities encased in an extracellular matrix. Here, Yan et al. show that matrix production in Vibrio cholerae increases the osmotic pressure within the biofilm, promoting biofilm expansion and physical exclusion of non-matrix producing cheaters.

By activating matrix metalloproteinase-7, shear stress promotes chondrosarcoma cell motility, invasion and lung colonization.

Science.gov (United States)

Guan, Pei-Pei; Yu, Xin; Guo, Jian-Jun; Wang, Yue; Wang, Tao; Li, Jia-Yi; Konstantopoulos, Konstantinos; Wang, Zhan-You; Wang, Pu

2015-04-20

Interstitial fluid flow and associated shear stress are relevant mechanical signals in cartilage and bone (patho)physiology. However, their effects on chondrosarcoma cell motility, invasion and metastasis have yet to be delineated. Using human SW1353, HS.819.T and CH2879 chondrosarcoma cell lines as model systems, we found that fluid shear stress induces the accumulation of cyclic AMP (cAMP) and interleukin-1β (IL-1β), which in turn markedly enhance chondrosarcoma cell motility and invasion via the induction of matrix metalloproteinase-7 (MMP-7). Specifically, shear-induced cAMP and IL-1β activate PI3-K, ERK1/2 and p38 signaling pathways, which lead to the synthesis of MMP-7 via transactivating NF-κB and c-Jun in human chondrosarcoma cells. Importantly, MMP-7 upregulation in response to shear stress exposure has the ability to promote lung colonization of chondrosarcomas in vivo. These findings offer a better understanding of the mechanisms underlying MMP-7 activation in shear-stimulated chondrosarcoma cells, and provide insights on designing new therapeutic strategies to interfere with chondrosarcoma invasion and metastasis.

CDP-choline modulates matrix metalloproteinases in rat sciatic injury.

Science.gov (United States)

Gundogdu, Elif Basaran; Bekar, Ahmet; Turkyilmaz, Mesut; Gumus, Abdullah; Kafa, Ilker Mustafa; Cansev, Mehmet

2016-02-01

CDP-choline (cytidine-5'-diphosphocholine) improves functional recovery, promotes nerve regeneration, and decreases perineural scarring in rat peripheral nerve injury. The aim of the present study was to investigate the mechanism of action of CDP-choline with regard to matrix metalloproteinase (MMP) activity in the rat-transected sciatic nerve injury model. Male Wistar rats were randomized into Sham, Saline, and CDP-choline groups. Rats in Sham group received Sham surgery, whereas rats in Saline and CDP-choline groups underwent right sciatic nerve transection followed by immediate primary saturation and injected intraperitoneally with 0.9% NaCl (1 mL/kg) and CDP-choline (600 μg/kg), respectively. Sciatic nerve samples were obtained 1, 3, and 7 d after the surgery and analyzed for levels and activities of MMP-2 and MMP-9, levels of tissue inhibitor of metalloproteinases-1 (TIMP-1) and TIMP-3, and axonal regeneration. CDP-choline treatment decreased the levels and activities of MMP-2 and MMP-9, whereas increasing levels of TIMP-1 and TIMP-3 significantly on the third and seventh day after injury compared to Saline group. In addition, CDP-choline administration resulted in new axon formation and formation and advancement of myelination on newly formed islets (compartments) of axonal regrowth. Our data show, for the first time, that CDP-choline modulates MMP activity and promotes the expression of TIMPs to stimulate axonal regeneration. These data help to explain one mechanism by which CDP-choline provides neuroprotection in peripheral nerve injury. Copyright © 2016 Elsevier Inc. All rights reserved.

NEW METHODS FOR IMPLANT MATRIX FORMATION BASED ON ELECTROSPINNING AND BIOPRINTING TECHNOLOGIES

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V. N. Vasilets

2009-01-01

Full Text Available New implant materials for regenerative and replacement surgery based on biodegradable polymers like collagens and polyoxybutirates are developed. Porous structures with controllable morphology were formed from biodegradable polymers using electrospinning and bioprinting technologies. The matrixes were studied by visible and electron scanning microscopy as well as INTEGRA Tomo scanning probe platform making possible the restoration of inner 3D structure of polymer matrix. 

Reduction of inflammatory responses and enhancement of extracellular matrix formation by vanillin-incorporated poly(lactic-co-glycolic acid) scaffolds.

Science.gov (United States)

Lee, Yujung; Kwon, Jeongil; Khang, Gilson; Lee, Dongwon

2012-10-01

Vanillin is one of the major components of vanilla, a commonly used flavoring agent and preservative and is known to exert potent antioxidant and anti-inflammatory activities. In this work, vanillin-incorporated poly(lactic-co-glycolic acid) (PLGA) films and scaffolds were fabricated to evaluate the effects of vanillin on the inflammatory responses and extracellular matrix (ECM) formation in vitro and in vivo. The incorporation of vanillin to PLGA films induced hydrophilic nature, resulting in the higher cell attachment and proliferation than the pure PLGA film. Vanillin also reduced the generation of reactive oxygen species (ROS) in cells cultured on the pure PLGA film and significantly inhibited the PLGA-induced inflammatory responses in vivo, evidenced by the reduced accumulation of inflammatory cells and thinner fibrous capsules. The effects of vanillin on the ECM formation were evaluated using annulus fibrous (AF) cell-seeded porous PLGA/vanillin scaffolds. PLGA/vanillin scaffolds elicited the more production of glycosaminoglycan and collagen than the pure PLGA scaffold, in a concentration-dependent manner. Based on the low level of inflammatory responses and enhanced ECM formation, vanillin-incorporated PLGA constructs make them promising candidates in the future biomedical applications.

Reduction of Inflammatory Responses and Enhancement of Extracellular Matrix Formation by Vanillin-Incorporated Poly(Lactic-co-Glycolic Acid) Scaffolds

Science.gov (United States)

Lee, Yujung; Kwon, Jeongil; Khang, Gilson

2012-01-01

Vanillin is one of the major components of vanilla, a commonly used flavoring agent and preservative and is known to exert potent antioxidant and anti-inflammatory activities. In this work, vanillin-incorporated poly(lactic-co-glycolic acid) (PLGA) films and scaffolds were fabricated to evaluate the effects of vanillin on the inflammatory responses and extracellular matrix (ECM) formation in vitro and in vivo. The incorporation of vanillin to PLGA films induced hydrophilic nature, resulting in the higher cell attachment and proliferation than the pure PLGA film. Vanillin also reduced the generation of reactive oxygen species (ROS) in cells cultured on the pure PLGA film and significantly inhibited the PLGA-induced inflammatory responses in vivo, evidenced by the reduced accumulation of inflammatory cells and thinner fibrous capsules. The effects of vanillin on the ECM formation were evaluated using annulus fibrous (AF) cell-seeded porous PLGA/vanillin scaffolds. PLGA/vanillin scaffolds elicited the more production of glycosaminoglycan and collagen than the pure PLGA scaffold, in a concentration-dependent manner. Based on the low level of inflammatory responses and enhanced ECM formation, vanillin-incorporated PLGA constructs make them promising candidates in the future biomedical applications. PMID:22551555

Research on the promoting role of apelin-13 in proliferation, migration and capillary-like tube formation of RF/6A cells

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Kun-Peng Xie

2017-05-01

Full Text Available AIM: To investigate the effects of apelin-13 on proliferation, migration and capillary-like tube formation of a monkey choroid / retinal endothelial cell line, RF/6A, to clarify whether apelin-13 could promote retinal angiogenesis in vitro.METHODS: RF/6A cells in good conditions were administrated with DMSO(the control group, apelin-13 at 0.1μmol/L(low dose groupor apelin-13 at 1μmol/L(high dose group. Cell proliferation, migration and capillary-like tube formation were detected by using the MTT assay, scratch assay and matrigel assay, respectively, at 24h after plating the cells. RESULTS: Cell proliferation was promoted in both low and high dose apelin-13 groups compared to the control cells(PPPCONCLUSION: Apelin-13 could obviously promote the angiogenesis capacity of RF/6A cells, suggesting that apelin-13 was an important pro-angiogenic factor in retinal endothelial cells.

IL-10 Promotes Neurite Outgrowth and Synapse Formation in Cultured Cortical Neurons after the Oxygen-Glucose Deprivation via JAK1/STAT3 Pathway.

Science.gov (United States)

Chen, Hongbin; Lin, Wei; Zhang, Yixian; Lin, Longzai; Chen, Jianhao; Zeng, Yongping; Zheng, Mouwei; Zhuang, Zezhong; Du, Houwei; Chen, Ronghua; Liu, Nan

2016-07-26

As a classic immunoregulatory and anti-inflammatory cytokine, interleukin-10 (IL-10) provides neuroprotection in cerebral ischemia in vivo or oxygen-glucose deprivation (OGD)-induced injury in vitro. However, it remains blurred whether IL-10 promotes neurite outgrowth and synapse formation in cultured primary cortical neurons after OGD injury. In order to evaluate its effect on neuronal apoptosis, neurite outgrowth and synapse formation, we administered IL-10 or IL-10 neutralizing antibody (IL-10NA) to cultured rat primary cortical neurons after OGD injury. We found that IL-10 treatment activated the Janus kinase 1 (JAK1)/signal transducers and activators of transcription 3 (STAT3) signaling pathway. Moreover, IL-10 attenuated OGD-induced neuronal apoptosis by down-regulating the Bax expression and up-regulating the Bcl-2 expression, facilitated neurite outgrowth by increasing the expression of Netrin-1, and promoted synapse formation in cultured primary cortical neurons after OGD injury. These effects were partly abolished by JAK1 inhibitor GLPG0634. Contrarily, IL-10NA produced opposite effects on the cultured cortical neurons after OGD injury. Taken together, our findings suggest that IL-10 not only attenuates neuronal apoptosis, but also promotes neurite outgrowth and synapse formation via the JAK1/STAT3 signaling pathway in cultured primary cortical neurons after OGD injury.

Influence of temperature and rooting-promoter on the formation of root-primodia and on the rooting of chrysanthemum cuttings under storage

International Nuclear Information System (INIS)

Nishio, J.; Fukuda, M.

1998-01-01

In order to promote rooting for direct planting cuttings in a lighting cultivation of chrysanthemum, we clarified the effects of light, temperature and term of storage of the cuttings, and analyzed ways of using rooting promoters as a pre-treatment of cuttings for root-primodia formation and rooting. Light as a pre-treatment had little effect, so it seemed to be not necessary for the formation of root primodia. The formation of the root-primodia was most hastened at 25 degrees C; inversely, it was slowed down at low temperatures, that is, the root-primodia were formed in four days at 25 degrees C, five days at 20 degrees C, and seven days at 15 degrees C. With the use of rooting promoters as a pre-treatment for the rooting of cuttings, the root-primodia were formed faster when the whole of cuttings were dipped in 40 mg/L solution of indelebutyric acid (IBA) than when the base of cuttings were dipped or sprayed 400 mg/L solution of IBA. It was appropriate that cuttings were dipped in IBA then put in in plastic-pots (7.5cm) vertically, packed in polyethylene-bags and stored in a corrugated carton box

Oxytocin promotes bone formation during the alveolar healing process in old acyclic female rats.

Science.gov (United States)

Colli, Vilma Clemi; Okamoto, Roberta; Spritzer, Poli Mara; Dornelles, Rita Cássia Menegati

2012-09-01

OT was reported to be a direct regulator of bone mass in young rodents, and this anabolic effect on bone is a peripheral action of OT. The goal of this study was to investigate the peripheral action of oxytocin (OT) in the alveolar healing process in old female rats. Females Wistar rats (24-month-old) in permanent diestrus phase, received two ip (12h apart) injections of saline (NaCl 0.15M - control group) or OT (45μg/rat - treated group). Seven days later, the right maxillary incisor was extracted and analyses were performed up to 28 days of the alveolar healing process (35 days after saline or OT administration). Calcium and phosphorus plasma concentrations did not differ between the groups. The plasma biochemical bone formations markers, alkaline phosphatase (ALP) and osteocalcin were significantly higher in the treated group. Histomorphometric analyses confirmed bone formation as the treated group presented the highest mean value of post-extraction bone formation. Tartrate-resistant acid phosphatase (TRAP) was significantly reduced in the treated group indicating an anti-resorptive effect of OT. Immunohistochemistry reactions performed in order to identify the presence of osteocalcin and TRAP in the bone cells of the dental socket confirmed these outcomes. OT was found to promote bone formation and to inhibit bone resorption in old acyclic female rats during the alveolar healing process. Published by Elsevier Ltd.

High fidelity visualization of cell-to-cell variation and temporal dynamics in nascent extracellular matrix formation.

Science.gov (United States)

McLeod, Claire M; Mauck, Robert L

2016-12-12

Extracellular matrix dynamics are key to tissue morphogenesis, homeostasis, injury, and repair. The spatiotemporal organization of this matrix has profound biological implications, but is challenging to monitor using standard techniques. Here, we address these challenges by using noncanonical amino acid tagging to fluorescently label extracellular matrix synthesized in the presence of bio-orthogonal methionine analogs. This strategy labels matrix proteins with high resolution, without compromising their distribution or mechanical function. We demonstrate that the organization and temporal dynamics of the proteinaceous matrix depend on the biophysical features of the microenvironment, including the biomaterial scaffold and the niche constructed by cells themselves. Pulse labeling experiments reveal that, in immature constructs, nascent matrix is highly fibrous and interdigitates with pre-existing matrix, while in more developed constructs, nascent matrix lacks fibrous organization and is retained in the immediate pericellular space. Inhibition of collagen crosslinking increases matrix synthesis, but compromises matrix organization. Finally, these data demonstrate marked cell-to-cell heterogeneity amongst both chondrocytes and mesenchymal stem cells undergoing chondrogenesis. Collectively, these results introduce fluorescent noncanonical amino acid tagging as a strategy to investigate spatiotemporal matrix organization, and demonstrate its ability to identify differences in phenotype, microenvironment, and matrix assembly at the single cell level.

Regeneration of soft tissues is promoted by MMP1 treatment after digit amputation in mice.

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Xiaodong Mu

Full Text Available The ratio of matrix metalloproteinases (MMPs to the tissue inhibitors of metalloproteinases (TIMPs in wounded tissues strictly control the protease activity of MMPs, and therefore regulate the progress of wound closure, tissue regeneration and scar formation. Some amphibians (i.e. axolotl/newt demonstrate complete regeneration of missing or wounded digits and even limbs; MMPs play a critical role during amphibian regeneration. Conversely, mammalian wound healing re-establishes tissue integrity, but at the expense of scar tissue formation. The differences between amphibian regeneration and mammalian wound healing can be attributed to the greater ratio of MMPs to TIMPs in amphibian tissue. Previous studies have demonstrated the ability of MMP1 to effectively promote skeletal muscle regeneration by favoring extracellular matrix (ECM remodeling to enhance cell proliferation and migration. In this study, MMP1 was administered to the digits amputated at the mid-second phalanx of adult mice to observe its effect on digit regeneration. Results indicated that the regeneration of soft tissue and the rate of wound closure were significantly improved by MMP1 administration, but the elongation of the skeletal tissue was insignificantly affected. During digit regeneration, more mutipotent progenitor cells, capillary vasculature and neuromuscular-related tissues were observed in MMP1 treated tissues; moreover, there was less fibrotic tissue formed in treated digits. In summary, MMP1 was found to be effective in promoting wound healing in amputated digits of adult mice.

Integrins and extracellular matrix in mechanotransduction

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Ramage L

2011-12-01

Full Text Available Lindsay RamageQueen’s Medical Research Institute, University of Edinburgh, Edinburgh, UKAbstract: Integrins are a family of cell surface receptors which mediate cell–matrix and cell–cell adhesions. Among other functions they provide an important mechanical link between the cells external and intracellular environments while the adhesions that they form also have critical roles in cellular signal-transduction. Cell–matrix contacts occur at zones in the cell surface where adhesion receptors cluster and when activated the receptors bind to ligands in the extracellular matrix. The extracellular matrix surrounds the cells of tissues and forms the structural support of tissue which is particularly important in connective tissues. Cells attach to the extracellular matrix through specific cell-surface receptors and molecules including integrins and transmembrane proteoglycans. Integrins work alongside other proteins such as cadherins, immunoglobulin superfamily cell adhesion molecules, selectins, and syndecans to mediate cell–cell and cell–matrix interactions and communication. Activation of adhesion receptors triggers the formation of matrix contacts in which bound matrix components, adhesion receptors, and associated intracellular cytoskeletal and signaling molecules form large functional, localized multiprotein complexes. Cell–matrix contacts are important in a variety of different cell and tissue properties including embryonic development, inflammatory responses, wound healing, and adult tissue homeostasis. This review summarizes the roles and functions of integrins and extracellular matrix proteins in mechanotransduction.Keywords: ligand binding, α subunit, ß subunit, focal adhesion, cell differentiation, mechanical loading, cell–matrix interaction

Library designs for generic C++ sparse matrix computations of iterative methods

Energy Technology Data Exchange (ETDEWEB)

Pozo, R.

1996-12-31

A new library design is presented for generic sparse matrix C++ objects for use in iterative algorithms and preconditioners. This design extends previous work on C++ numerical libraries by providing a framework in which efficient algorithms can be written *independent* of the matrix layout or format. That is, rather than supporting different codes for each (element type) / (matrix format) combination, only one version of the algorithm need be maintained. This not only reduces the effort for library developers, but also simplifies the calling interface seen by library users. Furthermore, the underlying matrix library can be naturally extended to support user-defined objects, such as hierarchical block-structured matrices, or application-specific preconditioners. Utilizing optimized kernels whenever possible, the resulting performance of such framework can be shown to be competitive with optimized Fortran programs.

Matrix metalloproteinase 2 is required for ovulation and corpus luteum formation in Drosophila.

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Lylah D Deady

2015-02-01

Full Text Available Ovulation is critical for successful reproduction and correlates with ovarian cancer risk, yet genetic studies of ovulation have been limited. It has long been thought that the mechanism controlling ovulation is highly divergent due to speciation and fast evolution. Using genetic tools available in Drosophila, we now report that ovulation in Drosophila strongly resembles mammalian ovulation at both the cellular and molecular levels. Just one of up to 32 mature follicles per ovary pair loses posterior follicle cells ("trimming" and protrudes into the oviduct, showing that a selection process prefigures ovulation. Follicle cells that remain after egg release form a "corpus luteum (CL" at the end of the ovariole, develop yellowish pigmentation, and express genes encoding steroid hormone biosynthetic enzymes that are required for full fertility. Finally, matrix metalloproteinase 2 (Mmp2, a type of protease thought to facilitate mammalian ovulation, is expressed in mature follicle and CL cells. Mmp2 activity is genetically required for trimming, ovulation and CL formation. Our studies provide new insights into the regulation of Drosophila ovulation and establish Drosophila as a model for genetically investigating ovulation in diverse organisms, including mammals.

The exopolysaccharide gene cluster Bcam1330-Bcam1341 is involved in Burkholderia cenocepacia biofilm formation, and its expression is regulated by c-di-GMP and Bcam1349

DEFF Research Database (Denmark)

Fazli, Mustafa; McCarthy, Yvonne; Givskov, Michael

2013-01-01

In Burkholderia cenocepacia, the second messenger cyclic diguanosine monophosphate (c-di-GMP) has previously been shown to positively regulate biofilm formation and the expression of cellulose and type-I fimbriae genes through binding to the transcriptional regulator Bcam1349. Here, we provide...... evidence that cellulose and type-I fimbriae are not involved in B. cenocepacia biofilm formation in flow chambers, and we identify a novel Bcam1349/c-di-GMP-regulated exopolysaccharide gene cluster which is essential for B. cenocepacia biofilm formation. Overproduction of Bcam1349 in trans promotes wrinkly...... matrix exopolysaccharide and to be essential for flow-chamber biofilm formation. We demonstrate that Bcam1349 binds to the promoter region of genes in the Bcam1330-Bcam1341 cluster and that this binding is enhanced by the presence of c-di-GMP. Furthermore, we demonstrate that overproduction of both c-di-GMP...

Demineralized bone matrix fibers formable as general and custom 3D printed mold-based implants for promoting bone regeneration.

Science.gov (United States)

Rodriguez, Rudy U; Kemper, Nathan; Breathwaite, Erick; Dutta, Sucharita M; Hsu, Erin L; Hsu, Wellington K; Francis, Michael P

2016-07-26

Bone repair frequently requires time-consuming implant construction, particularly when using un-formed implants with poor handling properties. We therefore developed osteoinductive, micro-fibrous surface patterned demineralized bone matrix (DBM) fibers for engineering both defect-matched and general three-dimensional implants. Implant molds were filled with demineralized human cortical bone fibers there were compressed and lyophilized, forming mechanically strong shaped DBM scaffolds. Enzyme linked immunosorbent assays and mass spectrometry confirmed that DBM fibers contained abundant osteogenic growth factors (bone morphogenetic proteins, insulin-like growth factor-I) and extracellular matrix proteins. Mercury porosimetry and mechanical testing showed interconnected pores within the mechanically stable, custom DBM fiber scaffolds. Mesenchymal stem cells readily attached to the DBM and showed increasing metabolic activity over time. DBM fibers further increased alkaline phosphatase activity in C2C12 cells. In vivo, DBM implants elicited osteoinductive potential in a mouse muscle pouch, and also promoted spine fusion in a rat arthrodesis model. DBM fibers can be engineered into custom-shaped, osteoinductive and osteoconductive implants with potential for repairing osseous defects with precise fitment, potentially reducing operating time. By providing pre-formed and custom implants, this regenerative allograft may improve patient outcomes following surgical bone repair, while further advancing personalized orthopedic and craniomaxillofacial medicine using three-dimensional-printed tissue molds.

Decreased hypertrophic differentiation accompanies enhanced matrix formation in co-cultures of outer meniscus cells with bone marrow mesenchymal stromal cells

Science.gov (United States)

2012-01-01

Introduction The main objective of this study was to determine whether meniscus cells from the outer (MCO) and inner (MCI) regions of the meniscus interact similarly to or differently with mesenchymal stromal stem cells (MSCs). Previous study had shown that co-culture of meniscus cells with bone marrow-derived MSCs result in enhanced matrix formation relative to mono-cultures of meniscus cells and MSCs. However, the study did not examine if cells from the different regions of the meniscus interacted similarly to or differently with MSCs. Methods Human menisci were harvested from four patients undergoing total knee replacements. Tissue from the outer and inner regions represented pieces taken from one third and two thirds of the radial distance of the meniscus, respectively. Meniscus cells were released from the menisci after collagenase treatment. Bone marrow MSCs were obtained from the iliac crest of two patients after plastic adherence and in vitro culture until passage 2. Primary meniscus cells from the outer (MCO) or inner (MCI) regions of the meniscus were co-cultured with MSCs in three-dimensional (3D) pellet cultures at 1:3 ratio, respectively, for 3 weeks in the presence of serum-free chondrogenic medium containing TGF-β1. Mono-cultures of MCO, MCI and MSCs served as experimental control groups. The tissue formed after 3 weeks was assessed biochemically, histochemically and by quantitative RT-PCR. Results Co-culture of inner (MCI) or outer (MCO) meniscus cells with MSCs resulted in neo-tissue with increased (up to 2.2-fold) proteoglycan (GAG) matrix content relative to tissues formed from mono-cultures of MSCs, MCI and MCO. Co-cultures of MCI or MCO with MSCs produced the same amount of matrix in the tissue formed. However, the expression level of aggrecan was highest in mono-cultures of MSCs but similar in the other four groups. The DNA content of the tissues from co-cultured cells was not statistically different from tissues formed from mono-cultures of

Activation of Wnt Planar Cell Polarity (PCP) signaling promotes growth plate column formation in vitro.

Science.gov (United States)

Randall, Rachel M; Shao, Yvonne Y; Wang, Lai; Ballock, R Tracy

2012-12-01

Disrupting the Wnt Planar Cell Polarity (PCP) signaling pathway in vivo results in loss of columnar growth plate architecture, but it is unknown whether activation of this pathway in vitro is sufficient to promote column formation. We hypothesized that activation of the Wnt PCP pathway in growth plate chondrocyte cell pellets would promote columnar organization in these cells that are normally oriented randomly in culture. Rat growth plate chondrocytes were transfected with plasmids encoding the Fzd7 cell-surface Wnt receptor, a Fzd7 deletion mutant lacking the Wnt-binding domain, or Wnt receptor-associated proteins Ror2 or Vangl2, and then cultured as three-dimensional cell pellets in the presence of recombinant Wnt5a or Wnt5b for 21 days. Cellular morphology was evaluated using histomorphometric measurements. Activation of Wnt PCP signaling components promoted the initiation of columnar morphogenesis in the chondrocyte pellet culture model, as measured by histomorphometric analysis of the column index (ANOVA p = 0.01). Activation of noncanonical Wnt signaling through overexpression of both the cell-surface Wnt receptor Fzd7 and receptor-associated protein Ror2 with addition of recombinant Wnt5a promotes the initiation of columnar architecture of growth plate chondrocytes in vitro, representing an important step toward growth plate regeneration. Copyright © 2012 Orthopaedic Research Society.

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander

2015-01-05

We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(nlogn). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and op- timal design.

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander; Genton, Marc G.; Sun, Ying; Tempone, Raul

2015-01-01

We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(nlogn). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and op- timal design.

Direct synthesis of II-VI compound nanocrystals in polymer matrix

International Nuclear Information System (INIS)

Antolini, F.; Di Luccio, T.; Laera, A.M.; Mirenghi, L.; Piscopiello, E.; Re, M.; Tapfer, L.

2007-01-01

The production of II-VI semiconductor compound - polymer matrix nanocomposites by a direct in-situ thermolysis process is described. Metal-thiolate precursor molecules embedded in a polymer matrix decompose by a thermal annealing and the nucleation of semiconductor nanocrystals occurs. It is shown that the nucleation of nanoparticles and the formation of the nanocomposite can be also achieved by laser beam irradiation; this opens the way towards a ''lithographic'' in-situ nanocomposite production process. A possible growth and nanocomposite formation mechanism, describing the structural and chemical transformation of the precursor molecules, their decomposition and the formation of the nanoparticles, is presented. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Effect of enamel organic matrix on the potential of Galla chinensis to promote the remineralization of initial enamel carious lesions in vitro

Energy Technology Data Exchange (ETDEWEB)

Zhang Linglin; Zou Ling; Li Jiyao; Hao Yuqing; Xiao Liying; Zhou Xuedong; Li Wei, E-mail: leewei2000@sina.co, E-mail: zhll_sc@yahoo.c [State Key Laboratory of Oral Diseases, West China College of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu (China)

2009-06-15

Galla chinensis, a natural traditional Chinese medicine with main composition of tannic acid and gallic acid, is formed when the Chinese sumac aphid Baker (Melaphis chinensis bell) parasitizes the levels of Rhus chinensis Mill. Galla chinensis has shown the potential to enhance the remineralization of initial enamel carious lesion, but the mechanism is still unknown. This study was to investigate whether the enamel organic matrix plays a significant role in the potential of Galla chinensis to promote the remineralization of initial enamel caries. Bovine sound enamel blocks and non-organic enamel blocks were demineralized and exposed to a 12 day pH cycling. During the pH cycling, 30 specimens with the enamel organic matrix were randomly divided into three groups, and treated with 1 g L{sup -1} NaF (group A), 4 g L{sup -1} Galla chinensis extract (group B1) or double deionized water (group C1). Twenty specimens without the enamel organic matrix were randomly divided into two groups, and treated with 4 g L{sup -1} Galla chinensis extract (group B2) or double deionized water (group C2). The integrated mineral loss and lesion depth of all the specimens were analysed by transverse microradiography. The integrated mineral loss and lesion depth of group B1 were less than those of groups B2, C1 and C2, and there were no statistical differences among groups B2, C1 and C2. In conclusion, Galla chinensis can enhance the remineralization of initial enamel carious lesion, and the enamel organic matrix plays a significant role in this potential of Galla chinensis.

Self-Ordered Voids Formation in SiO2 Matrix by Ge Outdiffusion

OpenAIRE

B. Pivac; P. Dubček; J. Dasović; H. Zorc; S. Bernstorff; J. Zavašnik; B. Vlahovic

2018-01-01

The annealing behavior of very thin SiO2/Ge multilayers deposited on Si substrate by e-gun deposition in high vacuum was explored. It is shown that, after annealing at moderate temperatures (800°C) in inert atmosphere, Ge is completely outdiffused from the SiO2 matrix leaving small (about 3 nm) spherical voids embedded in the SiO2 matrix. These voids are very well correlated and formed at distances governed by the preexisting multilayer structure (in vertical direction) and self-organization ...

A J matrix engine for density functional theory calculations

International Nuclear Information System (INIS)

White, C.A.; Head-Gordon, M.

1996-01-01

We introduce a new method for the formation of the J matrix (Coulomb interaction matrix) within a basis of Cartesian Gaussian functions, as needed in density functional theory and Hartree endash Fock calculations. By summing the density matrix into the underlying Gaussian integral formulas, we have developed a J matrix open-quote open-quote engine close-quote close-quote which forms the exact J matrix without explicitly forming the full set of two electron integral intermediates. Several precomputable quantities have been identified, substantially reducing the number of floating point operations and memory accesses needed in a J matrix calculation. Initial timings indicate a speedup of greater than four times for the (pp parallel pp) class of integrals with speedups increasing to over ten times for (ff parallel ff) integrals. copyright 1996 American Institute of Physics

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander

2015-01-07

We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(n log n). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and optimal design

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander; Genton, Marc G.; Sun, Ying; Tempone, Raul

2015-01-01

We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(n log n). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and optimal design

Matrix metalloproteinase 12 is induced by heterogeneous nuclear ribonucleoprotein K and promotes migration and invasion in nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Chung, I-Che; Li, Hsin-Pai; Chang, Yu-Sun; Chen, Lih-Chyang; Chung, An-Ko; Chao, Mei; Huang, Hsin-Yi; Hsueh, Chuen; Tsang, Ngan-Ming; Chang, Kai-Ping; Liang, Ying

2014-01-01

Overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a DNA/RNA binding protein, is associated with metastasis in nasopharyngeal carcinoma (NPC). However, the mechanisms underlying hnRNP K-mediated metastasis is unclear. The aim of the present study was to determine the role of matrix metalloproteinase (MMP) in hnRNP K-mediated metastasis in NPC. We studied hnRNP K-regulated MMPs by analyzing the expression profiles of MMP family genes in NPC tissues and hnRNP K-knockdown NPC cells using Affymetrix microarray analysis and quantitative RT-PCR. The association of hnRNP K and MMP12 expression in 82 clinically proven NPC cases was determined by immunohistochemical analysis. The hnRNP K-mediated MMP12 regulation was determined by zymography and Western blot, as well as by promoter, DNA pull-down and chromatin immunoprecipitation (ChIP) assays. The functional role of MMP12 in cell migration and invasion was demonstrated by MMP12-knockdown and the treatment of MMP12-specific inhibitor, PF-356231. MMP12 was overexpressed in NPC tissues, and this high level of expression was significantly correlated with high-level expression of hnRNP K (P = 0.026). The levels of mRNA, protein and enzyme activity of MMP12 were reduced in hnRNP K-knockdown NPC cells. HnRNP K interacting with the region spanning −42 to −33 bp of the transcription start site triggered transcriptional activation of the MMP12 promoter. Furthermore, inhibiting MMP12 by MMP12 knockdown and MMP12-specific inhibitor, PF-356231, significantly reduced the migration and invasion of NPC cells. Overexpression of MMP12 was significantly correlated with hnRNP K in NPC tissues. HnRNP K can induce MMP12 expression and enzyme activity through activating MMP12 promoter, which promotes cell migration and invasion in NPC cells. In vitro experiments suggest that NPC metastasis with high MMP12 expression may be treated with PF-356231. HnRNP K and MMP12 may be potential therapeutic markers for NPC, but

Formation and properties of selected quantum dots in maize amylopectin matrix

Energy Technology Data Exchange (ETDEWEB)

Khachatryan, Karen, E-mail: rrchacza@cyf-kr.edu.pl [Department of Chemistry and Physics, Agricultural University, Balicka Street 122, 30 149 Krakow (Poland); Khachatryan, Gohar; Fiedorowicz, Maciej [Department of Chemistry and Physics, Agricultural University, Balicka Street 122, 30 149 Krakow (Poland); Tomasik, Piotr [Krakow College of Health Promotion, Krowoderska Street 73, 31 158 Krakow (Poland)

2014-09-01

Highlights: • Synthesis of quantum dots in aqueous gel of amylopectin. • Generation of quantum dots in non-ionic polysaccharide. • Preparation of CdS, Ga{sub 2}S{sub 3} and ZnS quantum dots of the size below 10 nm. • The amylopectin matrix is not suitable for generation of CaS and Cs{sub 2}S quantum dots. - Abstract: CdS, ZnS, Ga{sub 2}S{sub 3}, CaS and Cs{sub 2}S quantum dots (QDs) were generated in the amylopectin (Ap) matrix. They all emitted a light between 460 (ZnS) and 475 (CdS) nm. Sizes of Ga{sub 2}S{sub 3} and CdS QDs were 7–9 nm and 5–7 nm, respectively. Single ZnS QDs had 6–7 nm but they readily aggregated. The CaS and Cs{sub 2}S appeared mainly as 30–100 nm aggregates. There were no significant interactions between QDs and the Ap matrix. Presented method appeared unsuitable for the generation of CaS and Cs{sub 2}S QDs as they as well as their substrates [Ca(NO{sub 3}){sub 2}] hydrolyzed. Calcium compounds formed complexes with Ap and alkaline solution from CsOH could produce cesium salts of Ap as well as cause oxidation of Ap.

biojs-io-biom, a BioJS component for handling data in Biological Observation Matrix (BIOM format [version 2; referees: 1 approved, 2 approved with reservations

Directory of Open Access Journals (Sweden)

Markus J. Ankenbrand

2017-01-01

Full Text Available The Biological Observation Matrix (BIOM format is widely used to store data from high-throughput studies. It aims at increasing interoperability of bioinformatic tools that process this data. However, due to multiple versions and implementation details, working with this format can be tricky. Currently, libraries in Python, R and Perl are available, whilst such for JavaScript are lacking. Here, we present a BioJS component for parsing BIOM data in all format versions. It supports import, modification, and export via a unified interface. This module aims to facilitate the development of web applications that use BIOM data. Finally, we demonstrate its usefulness by two applications that already use this component. Availability: https://github.com/molbiodiv/biojs-io-biom, https://dx.doi.org/10.5281/zenodo.218277

The Candida albicans Biofilm Matrix: Composition, Structure and Function.

Science.gov (United States)

Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L

2017-03-01

A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.

Combination of platelet-rich plasma within periodontal ligament stem cell sheets enhances cell differentiation and matrix production.

Science.gov (United States)

Xu, Qiu; Li, Bei; Yuan, Lin; Dong, Zhiwei; Zhang, Hao; Wang, Han; Sun, Jin; Ge, Song; Jin, Yan

2017-03-01

The longstanding goal of periodontal therapy is to regenerate periodontal tissues. Although platelet-rich plasma (PRP) has been gaining increasing popularity for use in the orofacial region, whether PRP is useful for periodontal regeneration is still unknown. The purpose of this study was to determine whether a mixture of periodontal ligament stem cell (PDLSC) sheets and PRP promoted bone regeneration, one of the most important measurement indices of periodontal tissue regenerative capability in vitro and in vivo. In this study, we evaluated the effects of different doses of PRP on the differentiation of human PDLSCs. Then cell sheet formation, extracellular matrix deposition and osteogenic gene expression in response to different doses of PRP treatment during sheet grafting was investigated. Furthermore, we implanted PDLSC sheets treated with 1% PRP subcutaneously into immunocompromised mice to evaluate their bone-regenerative capability. The results revealed that 1% PRP significantly enhanced the osteogenic differentiation of PDLSCs. Based on the production of extracellular matrix proteins, the results of scanning electron microscopy and the expression of the osteogenic genes ALP, Runx2, Col-1 and OCN, the provision of 1% PRP for PDLSC sheets was the most effective PRP administration mode for cell sheet formation. The results of in vivo transplantation showed that 1% PRP-mediated PDLSC sheets exhibited better periodontal tissue regenerative capability than those obtained without PRP intervention. These data suggest that a suitable concentration of PRP stimulation may enhance extracellular matrix production and positively affect cell behaviour in PDLSC sheets. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Alpha-Toxin Promotes Mucosal Biofilm Formation by Staphylococcus aureus

Directory of Open Access Journals (Sweden)

Michele J Anderson

2012-05-01

Full Text Available Staphylococcus aureus causes numerous diseases in humans ranging from the mild skin infections to serious, life-threatening, superantigen-mediated Toxic Shock Syndrome (TSS. S. aureus may also be asymptomatically carried in the anterior nares, vagina or on the skin, which serve as reservoirs for infection. Pulsed-field gel electrophoresis clonal type USA200 is the most widely disseminated colonizer and a major cause of TSS. Our prior studies indicated that α-toxin was a major epithelial proinflammatory exotoxin produced by TSS S. aureus USA200 isolates. It also facilitated the penetration of TSS Toxin-1 (TSST-1 across vaginal mucosa. However, the majority of menstrual TSS isolates produce low α-toxin due to a nonsense point mutation at codon 113, designated hly, suggesting mucosal adaptation. The aim of this study was to characterize the differences between TSS USA200 strains [high (hla+ and low (hly+ α-toxin producers] in their abilities to infect and disrupt vaginal mucosal tissue. A mucosal model was developed using ex vivo porcine vaginal mucosa, LIVE/DEAD® staining and confocal microscropy to characterize biofilm formation and tissue viability of TSS USA 200 isolates CDC587 and MN8, which contain the α-toxin pseudogene (hly, MNPE (hla+ and MNPE isogenic hla knockout (hlaKO. All TSS strains grew to similar bacterial densities (1-5 x 108 CFU on the mucosa and were proinflammatory over 3 days. However, MNPE formed biofilms with significant reductions in the mucosal viability whereas neither CDC587, MN8 (hly+, or MNPE hlaKO, formed biofilms and were less cytotoxic. The addition of exogenous, purified α-toxin to MNPE hlaKO restored the biofilm phenotype. Our studies suggest α-toxin affects S. aureus phenotypic growth on vaginal mucosa, by promoting tissue disruption and biofilm formation; and α–toxin mutants (hly are not benign colonizers, but rather form a different type of infection, which we have termed high density pathogenic

In situ study of the formation kinetics of InSb quantum dots grown in an InAs(Sb) matrix

International Nuclear Information System (INIS)

Semenov, A. N.; Lyublinskaya, O. G.; Solov’ev, V. A.; Mel’tser, B. Ya.; Ivanov, S. V.

2008-01-01

Formation of InSb quantum dots grown in an InAs matrix by molecular-beam epitaxy that does not involve forced deposition of InSb is studied. Detection of intensity oscillations in the reflection of high-energy electron diffraction patterns was used to study in situ the kinetics of the formation of InSb quantum dots and an InAsSb wetting layer. The effects of the substrate temperature, the shutter operation sequence, and the introduction of growth interruptions on the properties of the array of InSb quantum dots are examined. Introduction of a growth interruption immediately after completing the exposure of the InAs surface to the antimony flux leads to a reduction in the nominal thickness of InSb and to an enhancement in the uniformity of the quantum-dot array. It is shown that, in the case of deposition of submonolayer-thickness InSb/InAs quantum dots, the segregation layer of InAsSb plays the role of the wetting layer. The Sb segregation length and segregation ratio, as well as their temperature dependences, are determined.

Biomedical Application of Low Molecular Weight Heparin/Protamine Nano/Micro Particles as Cell- and Growth Factor-Carriers and Coating Matrix

Directory of Open Access Journals (Sweden)

Masayuki Ishihara

2015-05-01

Full Text Available Low molecular weight heparin (LMWH/protamine (P nano/micro particles (N/MPs (LMWH/P N/MPs were applied as carriers for heparin-binding growth factors (GFs and for adhesive cells including adipose-derived stromal cells (ADSCs and bone marrow-derived mesenchymal stem cells (BMSCs. A mixture of LMWH and P yields a dispersion of N/MPs (100 nm–3 μm in diameter. LMWH/P N/MPs can be immobilized onto cell surfaces or extracellular matrix, control the release, activate GFs and protect various GFs. Furthermore, LMWH/P N/MPs can also bind to adhesive cell surfaces, inducing cells and LMWH/P N/MPs-aggregate formation. Those aggregates substantially promoted cellular viability, and induced vascularization and fibrous tissue formation in vivo. The LMWH/P N/MPs, in combination with ADSCs or BMSCs, are effective cell-carriers and are potential promising novel therapeutic agents for inducing vascularization and fibrous tissue formation in ischemic disease by transplantation of the ADSCs and LMWH/P N/MPs-aggregates. LMWH/P N/MPs can also bind to tissue culture plates and adsorb exogenous GFs or GFs from those cells. The LMWH/P N/MPs-coated matrix in the presence of GFs may provide novel biomaterials that can control cellular activity such as growth and differentiation. Furthermore, three-dimensional (3D cultures of cells including ADSCs and BMSCs using plasma-medium gel with LMWH/P N/MPs exhibited efficient cell proliferation. Thus, LMWH/P N/MPs are an adequate carrier both for GFs and for stromal cells such as ADSCs and BMSCs, and are a functional coating matrix for their cultures.

[Levels of bone mineral matrix organization and the mechanisms determining parameters of its formation].

Science.gov (United States)

Avrunin, A S; Tikhilov, R M; Abolin, A B; Shcherbak, I G

2005-01-01

Authors suggest to regard bone mineral matrix as the four-level structure. The first level is represented by an internal structure of a mineral, the second--by mineral morphological structure, the third--by coplanar association of minerals, and the fourth--by macroassociation of minerals in a single complex inside each bone. The most probable mechanisms determining stability of reproduction of mineral matrix parameters on each of these levels are shown. As a result of their functioning, the variants of bone mineral matrix structures are formed that are the programmed reflection of specificity of the given site of organic structures.

Characteristics of Methane Hydrate Formation in Artificial and Natural Media

OpenAIRE

Peng Zhang; Qingbai Wu; Yuzhong Yang

2013-01-01

The formation of methane hydrate in two significantly different media was investigated, using silica gel as an artificial medium and loess as a natural medium. The methane hydrate formation was observed through the depletion of water in the matrix, measured via the matrix potential and the relationship between the matrix potential and the water content was determined using established equations. The velocity of methane hydrate nucleation slowed over the course of the reaction, as it relied on...

Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) promotes lung fibroblast proliferation, survival and differentiation to myofibroblasts.

Science.gov (United States)

Hasaneen, Nadia A; Cao, Jian; Pulkoski-Gross, Ashleigh; Zucker, Stanley; Foda, Hussein D

2016-02-17

Idiopathic pulmonary fibrosis (IPF) is a chronic progressively fatal disease. Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) is a glycosylated transmembrane protein that induces the expression of some matrix metalloproteinase (MMP) in neighboring stromal cells through direct epithelial-stromal interactions. EMMPRIN is highly expressed in type II alveolar epithelial cells at the edges of the fibrotic areas in IPF lung sections. However, the exact role of EMMPRIN in IPF is unknown. To determine if EMMPRIN contributes to lung fibroblast proliferation, resistance to apoptosis, and differentiation to myofibroblasts, normal Human lung fibroblasts (NHLF) transiently transfected with either EMMPRIN/GFP or GFP were treated with TGF- β1 from 0 to 10 ng/ml for 48 h and examined for cell proliferation (thymidine incorporation), apoptosis (FACS analysis and Cell Death Detection ELISA assay), cell migration (Modified Boyden chamber) and differentiation to myofibroblasts using Western blot for α-smooth actin of cell lysates. The effect of EMMPRIN inhibition on NHLF proliferation, apoptosis, migration and differentiation to myofibroblasts after TGF- β1 treatment was examined using EMMPRIN blocking antibody. We examined the mechanism by which EMMPRIN induces its effects on fibroblasts by studying the β-catenin/canonical Wnt signaling pathway using Wnt luciferase reporter assays and Western blot for total and phosphorylated β-catenin. Human lung fibroblasts overexpressing EMMPRIN had a significant increase in cell proliferation and migration compared to control fibroblasts. Furthermore, EMMPRIN promoted lung fibroblasts resistance to apoptosis. Lung fibroblasts overexpressing EMMPRIN showed a significantly increased expression of α- smooth muscle actin, a marker of differentiation to myofibroblasts compared to control cells. TGF-β1 increased the expression of EMMPRIN in lung fibroblasts in a dose-dependent manner. Attenuation of EMMPRIN expression with the use of an

Matrix protein of vesicular stomatitis virus: a potent inhibitor of vascular endothelial growth factor and malignant ascites formation.

Science.gov (United States)

Zhou, Y; Wen, F; Zhang, P; Tang, R; Li, Q

2013-03-01

Malignant ascites is common in various types of cancers and is difficult to manage. Vascular endothelial growth factor (VEGF) has a pivotal role in malignant ascites. The matrix protein of vesicular stomatitis virus (VSVMP) has been shown to inhibit host gene expression and induce the apoptosis of cancer cells. The present study was designed to determine whether VSVMP suppresses the formation of ascites in ascites-producing peritoneal carcinomatosis. BALB/c female mice, 6-8 weeks old, bearing peritoneal tumors of H22 or MethA cells received an intraperitoneal administration of 50 μg VSVMP/250 μg liposome complexes, 50 μg empty plasmid/250 μg liposome complexes or 0.9% NaCl solution, respectively, every 2 days for 3 weeks. Administration of VSVMP resulted in a significant inhibition in ascites formation, improvement in health condition and prolonged survival of the treated mice. Decreased peritoneum osmolarity and reduced tumor vascularity coincided with dramatic reductions in the VEGF level in ascites fluid and plasma. Examination of floating tumor cells collected from the peritoneal wash revealed an apparently increased number of apoptotic cells and profound downregulation of VEGF mRNA in the VSVMP-treated mice. Our data indicate for the first time that in BALB/c mice bearing H22 or MethA cell peritoneal tumors, VSVMP may inhibit VEGF production and suppress angiogenesis, consequently abolishing ascites formation.

The Extracellular Matrix of Candida albicans Biofilms Impairs Formation of Neutrophil Extracellular Traps.

Science.gov (United States)

Johnson, Chad J; Cabezas-Olcoz, Jonathan; Kernien, John F; Wang, Steven X; Beebe, David J; Huttenlocher, Anna; Ansari, Hamayail; Nett, Jeniel E

2016-09-01

Neutrophils release extracellular traps (NETs) in response to planktonic C. albicans. These complexes composed of DNA, histones, and proteins inhibit Candida growth and dissemination. Considering the resilience of Candida biofilms to host defenses, we examined the neutrophil response to C. albicans during biofilm growth. In contrast to planktonic C. albicans, biofilms triggered negligible release of NETs. Time lapse imaging confirmed the impairment in NET release and revealed neutrophils adhering to hyphae and migrating on the biofilm. NET inhibition depended on an intact extracellular biofilm matrix as physical or genetic disruption of this component resulted in NET release. Biofilm inhibition of NETosis could not be overcome by protein kinase C activation via phorbol myristate acetate (PMA) and was associated with suppression of neutrophil reactive oxygen species (ROS) production. The degree of impaired NET release correlated with resistance to neutrophil attack. The clinical relevance of the role for extracellular matrix in diminishing NET production was corroborated in vivo using a rat catheter model. The C. albicans pmr1Δ/Δ, defective in production of matrix mannan, appeared to elicit a greater abundance of NETs by scanning electron microscopy imaging, which correlated with a decreased fungal burden. Together, these findings show that C. albicans biofilms impair neutrophil response through an inhibitory pathway induced by the extracellular matrix.

Efficiency criterion for teleportation via channel matrix, measurement matrix and collapsed matrix

Directory of Open Access Journals (Sweden)

Xin-Wei Zha

Full Text Available In this paper, three kinds of coefficient matrixes (channel matrix, measurement matrix, collapsed matrix associated with the pure state for teleportation are presented, the general relation among channel matrix, measurement matrix and collapsed matrix is obtained. In addition, a criterion for judging whether a state can be teleported successfully is given, depending on the relation between the number of parameter of an unknown state and the rank of the collapsed matrix. Keywords: Channel matrix, Measurement matrix, Collapsed matrix, Teleportation

The roles of TGF-beta1 gene transfer on collagen formation during Achilles tendon healing.

Science.gov (United States)

Hou, Yu; Mao, ZeBing; Wei, XueLei; Lin, Lin; Chen, LianXu; Wang, HaiJun; Fu, Xin; Zhang, JiYing; Yu, ChangLong

2009-05-29

Collagen content and cross-linking are believed to be major determinants of tendon structural integrity and function. The current study aimed to investigate the effects of transforming growth factor (TGF)-beta1 on the collagen content and cross-linking of Achilles tendons, and on the histological and biomechanical changes occurring during Achilles tendon healing in rabbits. Bone marrow-derived mesenchymal stem cells (BMSCs) transfected with the TGF-beta1 gene were surgically implanted into experimentally injured Achilles tendons. Collagen proteins were identified by immunohistochemical staining and fiber bundle accumulation was revealed by Sirius red staining. Achilles tendons treated with TGF-beta1-transfected BMSCs showed higher concentrations of collagen I protein, more rapid matrix remodeling, and larger fiber bundles. Thus TGF-beta1 can promote mechanical strength in healing Achilles tendons by regulating collagen synthesis, cross-link formation, and matrix remodeling.

Sfp-type PPTase inactivation promotes bacterial biofilm formation and ability to enhance wheat drought tolerance

Directory of Open Access Journals (Sweden)

Salme eTimmusk

2015-05-01

Full Text Available Paenibacillus polymyxa is a common soil bacterium with broad range of practical applications. An important group of secondary metabolites in P. polymyxa are nonribosomal peptide and polyketide derived metabolites (NRP/PK. Modular nonribosomal peptide synthetases catalyse main steps in the biosynthesis of the complex secondary metabolites. Here we report on the inactivation of an A26 sfp-type phosphopantetheinyl transferase. The inactivation of the gene resulted in loss of NRP/PK production. In contrast to the former Bacillus spp. model the mutant strain compared to wild type showed greatly enhanced biofilm formation ability. Its biofilm promotion is directly mediated by NRP/PK, as exogenous addition of the wild type metabolite extracts restores its biofilm formation level. Wheat inoculation with bacteria that had lost their sfp-type PPTase gene resulted in two times higher plant survival and about three times increased biomass under severe drought stress compared to wild type.

Synthesis of zinc sulfide nanoparticles and their incorporation into poly(hydroxybutyrate) matrix in the formation of a novel nanocomposite

Science.gov (United States)

Riaz, Shahina; Raza, Zulfiqar Ali; Majeed, Muhammad Irfan; Jan, Tariq

2018-05-01

In the present study, zinc sulfide (ZnS) nanoparticles (NPs) were successfully synthesized through a modified chemical precipitation protocol and then mediated into poly(hydroxybutyrate) (PHB) matrix to get ZnS/PHB nanocomposite. Mean diameter and zeta potential of ZnS NPs, as determined using dynamic light scattering technique (DLS), were observed to be 53 nm and ‑89 mV, respectively. The structural investigations performed using x-ray diffraction (XRD) technique depicted the phase purity of ZnS NPs exhibiting cubic crystal structure. Fourier transform infrared (FTIR) spectroscopic analysis was conducted to identify the presence or absence of bonding vibrational modes on the surface of synthesized single phase ZnS NPs. The FTIR analysis confirmed the metal to sulphur bond formation by showing the characteristic band at 1123 cm‑1. The UV–vis absorption spectra of ZnS NPs confirmed the synthesis of particles in nanoscale regime showing a λ max of 302 nm. These NPs were then successfully incorporated into PHB matrix to synthesize ZnS/PHB nanocomposite. The synthesis of nanocomposite was confirmed by EDX analysis. The chemical bonding and structural properties of ZnS/PHB nanocomposite were determined by FTIR and XRD analysis, respectively. The FTIR analysis confirmed the synthesis of ZnS/PHB nanocomposite. Moreover, XRD analysis showed that structure of nanocomposite was completely controlled by ZnS NPs as pure PHB exhibited orthorhombic crystal structure while the nanocomposite demonstrated cubic crystal structure of ZnS. Thermal properties of nanocomposite were studied through thermogravimetric analysis revealing that the incorporation of ZnS NPs into PHB matrix lead to enhance heat resistance properties of PHB.

Petrology and geochemistry of the orbicular granitoid of Caldera, northern Chile. Models and hypotheses on the formation of radial orbicular textures

Science.gov (United States)

Díaz-Alvarado, Juan; Rodríguez, Natalia; Rodríguez, Carmen; Fernández, Carlos; Constanzo, Ítalo

2017-07-01

columnar and equiaxial crystallization. According to the obtained results, the formation of the orbicular granitoid of Caldera may have initiated 1) during the generation of a magmatic fracture in the crystallization front of the Relincho pluton, where the water released by the host crystal mush was dissolved in the new batch of dioritic magma. 2) The high influx of water-rich liquids induced superheating conditions in the newly intruding magma that became a depolymerized liquid, where the only solid particules were the small irregular fragments of the host mush dragged from the fracture walls. 3) Volatile exsolution promoted crystallization under undercooling conditions. 4) Undercooling and nucleation around the core (cold germs) involved the physical and geochemical fractionation between two sub-systems: a gabbroic sub-system that comprises the solid paragénesis with a residual water-rich liquid and a granodioritic sub-system. 5) The orbicules, including core and inner shell, behaved as viscous bodies (crystals + residual liquid) floating in the granodioritic magma. 6) Higher undercooling rates occurred at the starting stage, close to the liquidus, promoting columnar crystallization around the cores and formation of the shells. Conversely, in the granodioritic matrix sub-system, equiaxial crystallization was promoted by low relative crystallization rates. 7) The rest of the crystallization process evolved later in the outer shell and the matrix, as suggested by the poikilitic textures observed in both sides of the orbicule contact, and under conditions close to the solidus of both sub-systems (shell and matrix). The water-rich residual liquid expelled during the orbicular shell crystallization was mingled with the partially crystallized matrix magma, generating the pegmatitic domains with large Kfs megacrysts.

Highly scalable ZIF-based mixed-matrix hollow fiber membranes for advanced hydrocarbon separations

KAUST Repository

Zhang, Chen

2014-05-29

ZIF-8/6FDA-DAM, a proven mixed-matrix material that demonstrated remarkably enhanced C3H6/C3H8 selectivity in dense film geometry, was extended to scalable hollow fiber geometry in the current work. We successfully formed dual-layer ZIF-8/6FDA-DAM mixed-matrix hollow fiber membranes with ZIF-8 nanoparticle loading up to 30 wt % using the conventional dry-jet/wet-quench fiber spinning technique. The mixed-matrix hollow fibers showed significantly enhanced C3H6/C3H8 selectivity that was consistent with mixed-matrix dense films. Critical variables controlling successful formation of mixed-matrix hollow fiber membranes with desirable morphology and attractive transport properties were discussed. Furthermore, the effects of coating materials on selectivity recovery of partially defective fibers were investigated. To our best knowledge, this is the first article reporting successful formation of high-loading mixed-matrix hollow fiber membranes with significantly enhanced selectivity for separation of condensable olefin/paraffin mixtures. Therefore, it represents a major step in the research area of advanced mixed-matrix membranes. © 2014 American Institute of Chemical Engineers.

Mini-lecture course: Introduction into hierarchical matrix technique

KAUST Repository

Litvinenko, Alexander

2017-01-01

allows us to work with general class of matrices (not only structured or Toeplits or sparse). H-matrices can keep the H-matrix data format during linear algebra operations (inverse, update, Schur complement).

Influence of chloride admixtures on cement matrix durability

International Nuclear Information System (INIS)

Sheikh, I.A.; Zamorani, E.; Serrini, G.

1989-01-01

The influence of various inorganic salts, as chloride admixtures to Portland cement, on the mechanical properties and the durability of the matrix has been studied. The salts used in this study are chromium, nickel and cadmium chlorides. Improved compressive strength values are obtained which have been correlated to the stable metal hydroxide formation in high pH environment. Under static water conditions at 50 0 C, hydrolyzed chloride ions exhibit adverse effects on the matrix durability through rapid release of calcium as calcium chloride in the initial period of leaching. On the contrary, enhanced matrix durability is obtained on long term leaching in the case of cement containing chromium chloride

Phase difference between calcification and organic matrix formation in the diurnal growth of otoliths in rainbow trout, Salmo gairdneri

International Nuclear Information System (INIS)

Mugiya, Y.

1987-01-01

The relative role of calcium and organic matrix deposition in the formation of daily increments in otoliths was studied in in vitro preparations of otolith-containing sacculi of rainbow trout, Salmo gairdneri. Sacculi were incubated in a Ringer solution containing both 45 Ca and 3 H-glutamic acid for 2 hours at 6-h intervals throughout a 24-h period and then the uptake of these isotopes was determined for both otolith and saccular tissue fractions. Serum calcium and sodium concentrations were also analyzed for diurnal variations. Serum calcium concentrations varied diurnally by 8% in a single phasic pattern, reaching a peak at dusk (1600 h) and a nadir at night (2200 h), while sodium concentrations remained almost constant throughout a 24-h period. Diurnal variation in the otolith's uptake of calcium and glutamic acid showed discrete, antiphasic cycles. The rate of calcium uptake varied in a pattern closely resembling that of serum calcium (the peak at 1600 h and the nadir at 2200 h); glutamic acid uptake remained almost constant during the daytime and peaked at night (2200 h). The results indicate that in rainbow trout daily increments of otoliths are formed by the antiphasic deposition of calcium and organic matrix

NG2 proteoglycan increases mesangial cell proliferation and extracellular matrix production

International Nuclear Information System (INIS)

Xiong Jing; Wang Yang; Zhu, Zhonghua; Liu Jianshe; Wang Yumei; Zhang Chun; Hammes, Hans-Peter; Lang, Florian; Feng Yuxi

2007-01-01

As a membrane-spanning protein, NG2 chondroitin sulfate proteoglycan interacts with molecules on both sides of plasma membrane. The present study explored the role of NG2 in the pathogenesis of diabetic nephropathy. In the normal kidneys, NG2 was observed predominantly in glomerular mesangium, Bowman's capsule and interstitial vessels. Both mRNA and protein expression in kidneys was significantly higher in strepozotocin-induced diabetic rats than that in normal rats. In the cultured rat mesangial cell line HBZY-1, overexpression of NG2 promoted mesangial cell proliferation and extracellular matrix (ECM) production, such as type VI collagen and laminin. Furthermore, target knockdown of NG2 resulted in decreased cell proliferation and ECM formation. The observations suggest that NG2 is up-regulated in diabetic nephropathy. It actively participates in the development and progression of glomerulosclerosis by stimulating proliferation of mesangial cells and deposition of ECM

Patchwork structure-function analysis of the Sendai virus matrix protein.

Science.gov (United States)

Mottet-Osman, Geneviève; Miazza, Vincent; Vidalain, Pierre-Olivier; Roux, Laurent

2014-09-01

Paramyxoviruses contain a bi-lipidic envelope decorated by two transmembrane glycoproteins and carpeted on the inner surface with a layer of matrix proteins (M), thought to bridge the glycoproteins with the viral nucleocapsids. To characterize M structure-function features, a set of M domains were mutated or deleted. The genes encoding these modified M were incorporated into recombinant Sendai viruses and expressed as supplemental proteins. Using a method of integrated suppression complementation system (ISCS), the functions of these M mutants were analyzed in the context of the infection. Cellular membrane association, localization at the cell periphery, nucleocapsid binding, cellular protein interactions and promotion of viral particle formation were characterized in relation with the mutations. At the end, lack of nucleocapsid binding go together with lack of cell surface localization and both features definitely correlate with loss of M global function estimated by viral particle production. Copyright © 2014 Elsevier Inc. All rights reserved.

Interactions between the nuclear matrix and an enhancer of the tryptophan oxygenase gene

International Nuclear Information System (INIS)

Kaneoka, Hidenori; Miyake, Katsuhide; Iijima, Shinji

2009-01-01

The gene for tryptophan oxygenase (TO) is expressed in adult hepatocytes in a tissue- and differentiation-specific manner. The TO promoter has two glucocorticoid-responsive elements (GREs), and its expression is regulated by glucocorticoid hormone in the liver. We found a novel GRE in close proximity to a scaffold/matrix attachment region (S/MAR) that was located around -8.5 kb from the transcriptional start site of the TO gene by electrophoretic mobility shift and chromatin immunoprecipitation (ChIP) assays. A combination of nuclear fractionation and quantitative PCR analysis showed that the S/MAR was tethered to the nuclear matrix in both fetal and adult hepatocytes. ChIP assay showed that, in adult hepatocytes, the S/MAR-GRE and the promoter proximal regions interacted with lamin and heterogeneous nuclear ribonucleoprotein U in a dexamethasone dependent manner, but this was not the case in fetal cells, suggesting that developmental stage-specific expression of the TO gene might rely on the binding of the enhancer (the -8.5 kb S/MAR-GRE) and the promoter to the inner nuclear matrix.

Interactions between the nuclear matrix and an enhancer of the tryptophan oxygenase gene

Energy Technology Data Exchange (ETDEWEB)

Kaneoka, Hidenori [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Miyake, Katsuhide, E-mail: miyake@nubio.nagoya-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Iijima, Shinji [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2009-10-02

The gene for tryptophan oxygenase (TO) is expressed in adult hepatocytes in a tissue- and differentiation-specific manner. The TO promoter has two glucocorticoid-responsive elements (GREs), and its expression is regulated by glucocorticoid hormone in the liver. We found a novel GRE in close proximity to a scaffold/matrix attachment region (S/MAR) that was located around -8.5 kb from the transcriptional start site of the TO gene by electrophoretic mobility shift and chromatin immunoprecipitation (ChIP) assays. A combination of nuclear fractionation and quantitative PCR analysis showed that the S/MAR was tethered to the nuclear matrix in both fetal and adult hepatocytes. ChIP assay showed that, in adult hepatocytes, the S/MAR-GRE and the promoter proximal regions interacted with lamin and heterogeneous nuclear ribonucleoprotein U in a dexamethasone dependent manner, but this was not the case in fetal cells, suggesting that developmental stage-specific expression of the TO gene might rely on the binding of the enhancer (the -8.5 kb S/MAR-GRE) and the promoter to the inner nuclear matrix.

Topical hemostatic powder promotes reepithelialization and reduces scar formation after extensive esophageal mucosal resection.

Science.gov (United States)

Beye, B; Barret, M; Alatawi, A; Beuvon, F; Nicco, C; Pratico, C A; Chereau, C; Chaussade, S; Batteux, F; Prat, F

2016-08-01

The development of techniques for endoscopic resection has provided new strategies for radical conservative treatment of superficial esophageal neoplasms, even those that are circumferential, such as Barrett's neoplasia. However, it is necessary to prevent the formation of scar tissue that can be responsible for esophageal strictures following circumferential resection. Preliminary data have suggested the possible efficacy of a hemostatic powder in the promotion of wound healing. The study aims to assess the effectiveness of Hemospray (Cook Medical) in a swine model of post-endoscopic esophageal stricture. Our prospective controlled study included 21 pigs. A 6-cm circumferential submucosal dissection of the esophagus (CESD) was performed in each pig. Group 1 (n = 11) only underwent CESD and Group 2 (n = 10) had repeated Hemospray applications after CESD. Clinical, endoscopic, and radiological monitoring were performed, blood levels of four inflammatory or pro-fibrotic cytokines were assessed, and histological analysis was performed. Median esophageal diameter was greater in the group treated with Hemospray (2 mm [1-3] vs. 3 mm [2-4], P = 0.01), and the rate of symptomatic esophageal stricture was 100% and 60% in Groups 1 and 2, respectively (P = 0.09). The thicknesses of esophageal fibrosis and inflammatory cell infiltrate were significantly lower in Group 2 than in Group 1 (P = 0.002 and 0.0003, respectively). The length of the neoepithelium was greater in Group 2 than in Group 1 (P = 0.0004). Transforming growth factor-β levels were significantly lower in Group 2 than in Group 1 (P = 0.01). The application of Hemospray after esophageal CESD reduces scar tissue formation and promotes reepithelialization, and therefore is a promising therapeutic approach in the prevention of post-endoscopic esophageal stricture. © 2015 International Society for Diseases of the Esophagus.

Nuclear Energy Research Initiative. Development of a Stabilized Light Water Reactor Fuel Matrix for Extended Burnup

International Nuclear Information System (INIS)

BD Hanson; J Abrefah; SC Marschman; SG Prussin

2000-01-01

The main objective of this project is to develop an advanced fuel matrix capable of achieving extended burnup while improving safety margins and reliability for present operations. In the course of this project, the authors improve understanding of the mechanism for high burnup structure (HBS) formation and attempt to design a fuel to minimize its formation. The use of soluble dopants in the UO 2 matrix to stabilize the matrix and minimize fuel-side corrosion of the cladding is the main focus

Electrolyte matrix for molten carbonate fuel cells

Science.gov (United States)

Huang, C.M.; Yuh, C.Y.

1999-02-09

A matrix is described for a carbonate electrolyte including a support material and an additive constituent having a relatively low melting temperature and a relatively high coefficient of thermal expansion. The additive constituent is from 3 to 45 weight percent of the matrix and is formed from raw particles whose diameter is in a range of 0.1 {micro}m to 20 {micro}m and whose aspect ratio is in a range of 1 to 50. High energy intensive milling is used to mix the support material and additive constituent during matrix formation. Also disclosed is the use of a further additive constituent comprising an alkaline earth containing material. The further additive is mixed with the support material using high energy intensive milling. 5 figs.

Electrolyte matrix for molten carbonate fuel cells

Science.gov (United States)

Huang, Chao M.; Yuh, Chao-Yi

1999-01-01

A matrix for a carbonate electrolyte including a support material and an additive constituent having a relatively low melting temperature and a relatively high coefficient of thermal expansion. The additive constituent is from 3 to 45 weight percent of the matrix and is formed from raw particles whose diameter is in a range of 0.1 .mu.m to 20 .mu.m and whose aspect ratio is in a range of 1 to 50. High energy intensive milling is used to mix the support material and additive constituent during matrix formation. Also disclosed is the use of a further additive constituent comprising an alkaline earth containing material. The further additive is mixed with the support material using high energy intensive milling.

Widening the Scope of R-matrix Methods

Energy Technology Data Exchange (ETDEWEB)

Thompson, Ian J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dimitriou, Paraskevi [IAEA, Vienna (Austria); DeBoer, Richard J. [Nieuwland Science Hall, Notre Dame, IN (United States); Kunieda, Satoshi [Nuclear Data Center (JAEA), Tokai (Japan); Paris, Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thompson, Ian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Trkov, Andrej [IAEA, Vienna (Austria)

2016-03-01

A Consultant’s Meeting was held at the IAEA Headquarters, from 7 to 9 December 2015, to discuss the status of R-matrix codes currently used in calculations of charged-particle induced reaction cross sections at low energies. The ultimate goal was to initiate an international effort, coordinated by the IAEA, to evaluate charged-particle induced reactions in the resolved-resonance region. Participants reviewed the capabilities of the codes, the different implementations of R-matrix theory and translatability of the R-matrix parameters, the evaluation methods and suitable data formats for broader dissemination. The details of the presentations and technical discussions, as well as the actions that were proposed to achieve the goal of the meeting are summarized in this report.

Extracellular DNA as matrix component in microbial biofilms

DEFF Research Database (Denmark)

Chiang, Wen-Chi; Tolker-Nielsen, Tim

2010-01-01

Bacteria in nature primarily live in surface-associated communities commonly known as biofilms. Because bacteria in biofilms, in many cases, display tolerance to host immune systems, antibiotics, and biocides, they are often difficult or impossible to eradicate. Biofilm formation, therefore, leads...... to various persistent infections in humans and animals, and to a variety of complications in industry, where solid–water interfaces occur. Knowledge about the molecular mechanisms involved in biofilm formation is necessary for creating strategies to control biofilms. Recent studies have shown...... that extracellular DNA is an important component of the extracellular matrix of microbial biofilms. The present chapter is focussed on extracellular DNA as matrix component in biofilms formed by Pseudomonas aeruginosa as an example from the Gram-negative bacteria, and Streptococcus and Staphylococcus as examples...

Advances in biomimetic regeneration of elastic matrix structures

Science.gov (United States)

Sivaraman, Balakrishnan; Bashur, Chris A.

2012-01-01

Elastin is a vital component of the extracellular matrix, providing soft connective tissues with the property of elastic recoil following deformation and regulating the cellular response via biomechanical transduction to maintain tissue homeostasis. The limited ability of most adult cells to synthesize elastin precursors and assemble them into mature crosslinked structures has hindered the development of functional tissue-engineered constructs that exhibit the structure and biomechanics of normal native elastic tissues in the body. In diseased tissues, the chronic overexpression of proteolytic enzymes can cause significant matrix degradation, to further limit the accumulation and quality (e.g., fiber formation) of newly deposited elastic matrix. This review provides an overview of the role and importance of elastin and elastic matrix in soft tissues, the challenges to elastic matrix generation in vitro and to regenerative elastic matrix repair in vivo, current biomolecular strategies to enhance elastin deposition and matrix assembly, and the need to concurrently inhibit proteolytic matrix disruption for improving the quantity and quality of elastogenesis. The review further presents biomaterial-based options using scaffolds and nanocarriers for spatio-temporal control over the presentation and release of these biomolecules, to enable biomimetic assembly of clinically relevant native elastic matrix-like superstructures. Finally, this review provides an overview of recent advances and prospects for the application of these strategies to regenerating tissue-type specific elastic matrix structures and superstructures. PMID:23355960

Subinhibitory concentrations of cell wall synthesis inhibitors promote biofilm formation of Enterococcus faecalis

Science.gov (United States)

Yu, Wen; Hallinen, Kelsey; Wood, Kevin

Enterococcus faecalis are commonly associated with hospital acquired infections, because they readily form biofilms on instruments and medical devices. Biofilms are inherently more resistant to killing by antibiotics compared to planktonic bacteria, in part because of their heterogeneous spatial structure. Surprisingly, however, subminimal inhibitory concentrations (sub-MICs) of some antibiotics can actually promote biofilm formation. Unfortunately, much is still unknown about how low drug doses affect the composition and spatial structure of the biofilm. In this work, we investigate the effects of sub-MICs of ampicillin on the formation of E. faecalis biofilms. First, we quantified biofilm mass using crystal violet staining in polystyrene microtiter plates. We found that total biofilm mass is increased over a narrow range of ampicillin concentrations before ultimately declining at higher concentrations. Second, we show that sub-MICs of ampicillin can increase mass of E. faecalis biofilms while simultaneously increasing extracellular DNA/RNA and changing total number of viable cells under confocal microscopy. Further, we use RNA-seq to identify genes differentially expressed under sub-MICs of ampicillin. Finally, we show a mathematical model to explain this phenomenon. This work was funded by The Hartwell Foundation Individual Biomedical Research Award and NSF CAREER 1553208 to KBW.

PARTITIONING TUNGSTEN BETWEEN MATRIX PRECURSORS AND CHONDRULE PRECURSORS THROUGH RELATIVE SETTLING

Energy Technology Data Exchange (ETDEWEB)

Hubbard, Alexander, E-mail: ahubbard@amnh.org [American Museum of Natural History, New York, NY (United States)

2016-08-01

Recent studies of chondrites have found a tungsten isotopic anomaly between chondrules and matrix. Given the refractory nature of tungsten, this implies that W was carried into the solar nebula by at least two distinct families of pre-solar grains. The observed chondrule/matrix split requires that the distinct families were kept separate during the dust coagulation process, and that the two families of grain interacted with the chondrule formation mechanism differently. We take the co-existence of different families of solids in the same general orbital region at the chondrule-precursor size as given, and explore the requirements for them to have interacted with the chondrule formation process at significantly different rates. We show that this sorting of families of solids into chondrule- and matrix-destined dust had to have been at least as powerful a sorting mechanism as the relative settling of aerodynamically distinct grains at least two scale heights above the midplane. The requirement that the chondrule formation mechanism was correlated in some fashion with a dust-grain sorting mechanism argues strongly for spatially localized chondrule formation mechanisms such as turbulent dissipation in non-thermally ionized disk surface layers, and argues against volume-filling mechanisms such as planetesimal bow shocks.

PARTITIONING TUNGSTEN BETWEEN MATRIX PRECURSORS AND CHONDRULE PRECURSORS THROUGH RELATIVE SETTLING

International Nuclear Information System (INIS)

Hubbard, Alexander

2016-01-01

Recent studies of chondrites have found a tungsten isotopic anomaly between chondrules and matrix. Given the refractory nature of tungsten, this implies that W was carried into the solar nebula by at least two distinct families of pre-solar grains. The observed chondrule/matrix split requires that the distinct families were kept separate during the dust coagulation process, and that the two families of grain interacted with the chondrule formation mechanism differently. We take the co-existence of different families of solids in the same general orbital region at the chondrule-precursor size as given, and explore the requirements for them to have interacted with the chondrule formation process at significantly different rates. We show that this sorting of families of solids into chondrule- and matrix-destined dust had to have been at least as powerful a sorting mechanism as the relative settling of aerodynamically distinct grains at least two scale heights above the midplane. The requirement that the chondrule formation mechanism was correlated in some fashion with a dust-grain sorting mechanism argues strongly for spatially localized chondrule formation mechanisms such as turbulent dissipation in non-thermally ionized disk surface layers, and argues against volume-filling mechanisms such as planetesimal bow shocks.

Endocytosis and Enamel Formation

Directory of Open Access Journals (Sweden)

Cong-Dat Pham

2017-07-01

Full Text Available Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build the enamel layer (secretory stage and to reach final mineralization (maturation stage. Each stage has specific functional requirements for the ameloblasts. Ameloblasts adopt different cell morphologies during each stage. Protein trafficking including the secretion and endocytosis of enamel proteins is a fundamental task in ameloblasts. The sites of internalization of enamel proteins on the ameloblast membrane are specific for every stage. In this review, an overview of endocytosis and trafficking of vesicles in ameloblasts is presented. The pathways for internalization and routing of vesicles are described. Endocytosis is proposed as a mechanism to remove debris of degraded enamel protein and to obtain feedback from the matrix on the status of the maturing enamel.

Wnt3a Promotes the Vasculogenic Mimicry Formation of Colon Cancer via Wnt/β-Catenin Signaling.

Science.gov (United States)

Qi, Lisha; Song, Wangzhao; Liu, Zhiyong; Zhao, Xiulan; Cao, Wenfeng; Sun, Baocun

2015-08-10

Our previous study provided evidence that non-canonical Wnt signaling is involved in regulating vasculogenic mimicry (VM) formation. However, the functions of canonical Wnt signaling in VM formation have not yet been explored. In this study, we found the presence of VM was related to colon cancer histological differentiation (p colon cancer samples showed increased Wnt3a expression (p colon cancer cells promoted the capacity to form tube-like structures in the three-dimensional (3-D) culture together with increased expression of endothelial phenotype-associated proteins such as VEGFR2 and VE-cadherin. The mouse xenograft model showed that Wnt3a-overexpressing cells grew into larger tumor masses and formed more VM than the control cells. In addition, the Wnt/β-catenin signaling antagonist Dickkopf-1(Dkk1) can reverse the capacity to form tube-like structures and can decrease the expressions of VEGFR2 and VE-cadherin in Wnt3a-overexpressing cells. Taken together, our results suggest that Wnt/β-catenin signaling is involved in VM formation in colon cancer and might contribute to the development of more accurate treatment modalities aimed at VM.

Vinculin is required for cell polarization, migration, and extracellular matrix remodeling in 3D collagen.

Science.gov (United States)

Thievessen, Ingo; Fakhri, Nikta; Steinwachs, Julian; Kraus, Viola; McIsaac, R Scott; Gao, Liang; Chen, Bi-Chang; Baird, Michelle A; Davidson, Michael W; Betzig, Eric; Oldenbourg, Rudolf; Waterman, Clare M; Fabry, Ben

2015-11-01

Vinculin is filamentous (F)-actin-binding protein enriched in integrin-based adhesions to the extracellular matrix (ECM). Whereas studies in 2-dimensional (2D) tissue culture models have suggested that vinculin negatively regulates cell migration by promoting cytoskeleton-ECM coupling to strengthen and stabilize adhesions, its role in regulating cell migration in more physiologic, 3-dimensional (3D) environments is unclear. To address the role of vinculin in 3D cell migration, we analyzed the morphodynamics, migration, and ECM remodeling of primary murine embryonic fibroblasts (MEFs) with cre/loxP-mediated vinculin gene disruption in 3D collagen I cultures. We found that vinculin promoted 3D cell migration by increasing directional persistence. Vinculin was necessary for persistent cell protrusion, cell elongation, and stable cell orientation in 3D collagen, but was dispensable for lamellipodia formation, suggesting that vinculin-mediated cell adhesion to the ECM is needed to convert actin-based cell protrusion into persistent cell shape change and migration. Consistent with this finding, vinculin was necessary for efficient traction force generation in 3D collagen without affecting myosin II activity and promoted 3D collagen fiber alignment and macroscopical gel contraction. Our results suggest that vinculin promotes directionally persistent cell migration and tension-dependent ECM remodeling in complex 3D environments by increasing cell-ECM adhesion and traction force generation. © FASEB.

Calcium-Oxidant Signaling Network Regulates AMP-activated Protein Kinase (AMPK) Activation upon Matrix Deprivation*

Science.gov (United States)

Sundararaman, Ananthalakshmy; Amirtham, Usha; Rangarajan, Annapoorni

2016-01-01

The AMP-activated protein kinase (AMPK) has recently been implicated in anoikis resistance. However, the molecular mechanisms that activate AMPK upon matrix detachment remain unexplored. In this study, we show that AMPK activation is a rapid and sustained phenomenon upon matrix deprivation, whereas re-attachment to the matrix leads to its dephosphorylation and inactivation. Because matrix detachment leads to loss of integrin signaling, we investigated whether integrin signaling negatively regulates AMPK activation. However, modulation of focal adhesion kinase or Src, the major downstream components of integrin signaling, failed to cause a corresponding change in AMPK signaling. Further investigations revealed that the upstream AMPK kinases liver kinase B1 (LKB1) and Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) contribute to AMPK activation upon detachment. In LKB1-deficient cells, we found AMPK activation to be predominantly dependent on CaMKKβ. We observed no change in ATP levels under detached conditions at early time points suggesting that rapid AMPK activation upon detachment was not triggered by energy stress. We demonstrate that matrix deprivation leads to a spike in intracellular calcium as well as oxidant signaling, and both these intracellular messengers contribute to rapid AMPK activation upon detachment. We further show that endoplasmic reticulum calcium release-induced store-operated calcium entry contributes to intracellular calcium increase, leading to reactive oxygen species production, and AMPK activation. We additionally show that the LKB1/CaMKK-AMPK axis and intracellular calcium levels play a critical role in anchorage-independent cancer sphere formation. Thus, the Ca2+/reactive oxygen species-triggered LKB1/CaMKK-AMPK signaling cascade may provide a quick, adaptable switch to promote survival of metastasizing cancer cells. PMID:27226623

Studies of the structure and function of Mms6, a bacterial protein that promotes the formation of magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Wang, Lijun [Iowa State Univ., Ames, IA (United States)

2011-01-01

Here we report structural and functional studies of Mms6, a biomineralization protein that can promote the formation in vitro of magnetic nanoparticles with sizes and morphologies similar to the magnetites synthesized by magnetotactic bacteria. We found the binding pattern of Mms6 to ferric ion to be two-phase and multivalent. We quantatively determined that Mms6 binds one Fe³⁺ with a very high affinity (K_d = 10¹⁶ M). The second phase of iron binding is multivalent and cooperative with respect to iron with a K_d in the μM range and a stoichiometry of about 20 ferric ion per protein molecule. We found that Mms6 exists in large particles of two sizes, one consisting of 20-40 monomeric units and the other of 200 units. From proteolytic digestion, ultracentrifugation and liposome fusion studies, we found that Mms6 forms a large micellar quaternary structure with the N-terminal domain self-assembling into a uniformly sized micelle and the C-terminal domain on the surface. The two-phase iron-binding pattern may be relevant to iron crystal formation. We propose that the first high affinity phase may stabilize a new conformation of the C-terminal domain that allows interaction with other C-terminal domains leading to a structural change in the multimeric protein complex that enables the second low affinity iron binding phase to organize iron and initiate crystal formation. We also observed a dimeric apparent molecular mass of the Mms6 C-terminal peptide (C21Mms6). We speculate that the C-terminal domain may form higher order quaternary arrangements on the surface of the micelle or when anchored to a membrane by the N-terminal domain. The change in fluorescence quenching in the N-terminal domain with iron binding suggests a structural integrity between the C- and N-terminal domains. The slow change in trp fluorescence as a function of time after adding iron suggests a very slow conformational change in the protein that involves

L-plastin nanobodies perturb matrix degradation, podosome formation, stability and lifetime in THP-1 macrophages.

Directory of Open Access Journals (Sweden)

Sarah De Clercq

Full Text Available Podosomes are cellular structures acting as degradation 'hot-spots' in monocytic cells. They appear as dot-like structures at the ventral cell surface, enriched in F-actin and actin regulators, including gelsolin and L-plastin. Gelsolin is an ubiquitous severing and capping protein, whereas L-plastin is a leukocyte-specific actin bundling protein. The presence of the capping protein CapG in podosomes has not yet been investigated. We used an innovative approach to investigate the role of these proteins in macrophage podosomes by means of nanobodies or Camelid single domain antibodies. Nanobodies directed against distinct domains of gelsolin, L-plastin or CapG were stably expressed in macrophage-like THP-1 cells. CapG was not enriched in podosomes. Gelsolin nanobodies had no effect on podosome formation or function but proved very effective in tracing distinct gelsolin populations. One gelsolin nanobody specifically targets actin-bound gelsolin and was effectively enriched in podosomes. A gelsolin nanobody that blocks gelsolin-G-actin interaction was not enriched in podosomes demonstrating that the calcium-activated and actin-bound conformation of gelsolin is a constituent of podosomes. THP-1 cells expressing inhibitory L-plastin nanobodies were hampered in their ability to form stable podosomes. Nanobodies did not perturb Ser5 phosphorylation of L-plastin although phosphorylated L-plastin was highly enriched in podosomes. Furthermore, nanobody-induced inhibition of L-plastin function gave rise to an irregular and unstable actin turnover of podosomes, resulting in diminished degradation of the underlying matrix. Altogether these results indicate that L-plastin is indispensable for podosome formation and function in macrophages.

Matrix metalloproteinases (MMPs) safeguard osteoblasts from apoptosis during transdifferentiation into osteocytes

DEFF Research Database (Denmark)

Karsdal, M A; Levin Andersen, Thomas; Bonewald, L

2004-01-01

of osteoblasts forced to transdifferentiate into osteocytes in 3D type I collagen gels were inhibited by more than 50% when exposed to 10 microM GM6001 and to Tissue Inhibitor of Metalloproteinase-2 (TIMP-2), a natural MT1-MMP inhibitor. This shows the importance of MMPs in safeguarding osteoblasts from......Osteoblasts undergo apoptosis or differentiate into either osteocytes or bone-lining cells after termination of bone matrix synthesis. In this study, we investigated the role of matrix metalloproteinases (MMPs) in differentiation of osteoblasts, bone formation, transdifferentiation into osteocytes......, and osteocyte apoptosis. This was accomplished by using calvarial sections from the MT1-MMP-deficient mouse and by culture of the mouse osteoblast cell line MC3T3-E1 and primary mouse calvarial osteoblasts. We found that a synthetic matrix metalloprotease inhibitor, GM6001, strongly inhibited bone formation...

GENERALIZED MATRIXES OF GALOIS PROTOCOLS EXCHANGE ENCRYPTION KEYS

Directory of Open Access Journals (Sweden)

Anatoly Beletsky

2016-03-01

Full Text Available The methods of construction of matrix formation the secret protocols legalized subscribers of public communications networks encryption keys. Based key exchange protocols laid asymmetric cryptography algorithms. The solution involves the calculation of one-way functions and is based on the use of generalized Galois arrays of isomorphism relationship with forming elements, and depending on the selected irreducible polynomial generating matrix. A simple method for constructing generalized Galois matrix by the method of filling the diagonal. In order to eliminate the isomorphism of Galois arrays and their constituent elements, limiting the possibility of building one-way functions, Galois matrix subjected to similarity transformation carried out by means of permutation matrices. The variant of the organization of the algebraic attacks on encryption keys sharing protocols and discusses options for easing the consequences of an attack.

A review of biostratigraphic studies in the olistostrome deposits of Karangsambung Formation

Science.gov (United States)

Hendrizan, Marfasran

2018-02-01

Planktonic foraminifera is widely used for marine sediment biostratigraphy. Foraminiferal biostratigraphy of Karangsambung Formation is relatively rare to be investigated by previous researchers. A review of foraminiferal biostratigraphy is expected to be early work to perform a research about the ages of Tertiary rock formations in Karangsambung. The research area is formed by olistostrome process; a sedimentary slide deposit characterized by bodies of harder rock mixed and dispersed in a matrix. Biostratigraphic studies based on foraminifera and nannoplankton in Karangsambung Formation are still qualitative analysis using fossils biomarker. However, the age of this formation is still debatable based on foraminifera and nannofossil analysis. Two explanations of debatable ages in Karangsambung Formation that is possibly developed in Karangsambung area: firstly, Karangsambung Formation is characterized by normal sedimentation in some places and other regions such Kali Welaran and Clebok, Village as a product of olistostrome, and secondly, Karangsambung Formation is olistostrome deposit. However, micropaleontology sampling and analysis in matrix clays from olistostrome were ignored causing biostratigraphical results in those matrix clays occurred in normal sedimentation process and achieving the age of middle Eocene to Oligocene. We suppose previous authors picked samples in matrix of Karangsambung Formation from several river sections, which will make misinterpretation of the age of Karangsambung Formation. The age of middle to late Eocene probably is the dates of the older sediment that was reworked by sliding and sampling process and accumulated in Karangsambung Formation. The date of Karangsambung Fm is in Oligocene period based on a finding of several calcareous nannofossils. Detailed micropaleontological analysis of olistostrome deposits in Karangsambung Formation should be reevaluated for new finding of the accurate dating. Re-evaluation should start from

The gravitational S-matrix

CERN Document Server

Giddings, Steven B

2010-01-01

We investigate the hypothesized existence of an S-matrix for gravity, and some of its expected general properties. We first discuss basic questions regarding existence of such a matrix, including those of infrared divergences and description of asymptotic states. Distinct scattering behavior occurs in the Born, eikonal, and strong gravity regimes, and we describe aspects of both the partial wave and momentum space amplitudes, and their analytic properties, from these regimes. Classically the strong gravity region would be dominated by formation of black holes, and we assume its unitary quantum dynamics is described by corresponding resonances. Masslessness limits some powerful methods and results that apply to massive theories, though a continuation path implying crossing symmetry plausibly still exists. Physical properties of gravity suggest nonpolynomial amplitudes, although crossing and causality constrain (with modest assumptions) this nonpolynomial behavior, particularly requiring a polynomial bound in c...

Splenectomy after partial hepatectomy accelerates liver regeneration in mice by promoting tight junction formation via polarity protein Par 3-aPKC.

Science.gov (United States)

Liu, Guoxing; Xie, Chengzhi; Fang, Yu; Qian, Ke; Liu, Qiang; Liu, Gao; Cao, Zhenyu; Du, Huihui; Fu, Jie; Xu, Xundi

2018-01-01

Several experimental studies have demonstrated that removal of the spleen accelerates liver regeneration after partial hepatectomy. While the mechanism of splenectomy promotes liver regeneration by the improvement of the formation of tight junction and the establishment of hepatocyte polarity is still unknown. We analyzed the cytokines, genes and proteins expression between 70% partial hepatectomy mice (PHx) and simultaneous 70% partial hepatectomy and splenectomy mice (PHs) at predetermined timed points. Compared with the PHx group mice, splenectomy accelerated hepatocyte proliferation in PHs group. The expression of Zonula occludens-1 (ZO-1) indicated that splenectomy promotes the formation of tight junction during liver regeneration. TNF-α, IL-6, HGF, TSP-1 and TGF-β1 were essential factors for the formation of tight junction and the establishment of hepatocytes polarity in liver regeneration. After splenectomy, Partitioning defective 3 homolog (Par 3) and atypical protein kinase C (aPKC) regulate hepatocyte localization and junctional structures in regeneration liver. Our data suggest that the time course expression of TNF-α, IL-6, HGF, TSP-1, and TGF-β1 and the change of platelets take part in liver regeneration. Combination with splenectomy accelerates liver regeneration by improvement of the tight junction formation which may help to establish hepatocyte polarity via Par 3-aPKC. This may provide a clue for us that splenectomy could accelerate liver regeneration after partial hepatectomy of hepatocellular carcinoma and living donor liver transplantation. Copyright © 2017 Elsevier Inc. All rights reserved.

CD14+ monocytes promote the immunosuppressive effect of human umbilical cord matrix stem cells

International Nuclear Information System (INIS)

Wang, Ding; Chen, Ke; Du, Wei Ting; Han, Zhi-Bo; Ren, He; Chi, Ying

2010-01-01

Here, the effect of CD14 + monocytes on human umbilical cord matrix stem cell (hUC-MSC)-mediated immunosuppression was studied in vitro. hUC-MSCs exerted a potent inhibitory effect on the proliferation and interferon-γ (IFN-γ) secretion capacities of CD4 + and CD8 + T cells in response to anti-CD3/CD28 stimulation. Transwell co-culture system revealed that the suppressive effect was primarily mediated by soluble factors. Addition of prostaglandin synthesis inhibitors (indomethacin or NS-398) almost completely abrogated the immunosuppression activity of hUC-MSCs, identifying prostaglandin E 2 (PGE 2 ) as an important soluble mediator. CD14 + monocytes were found to be able to enhance significantly the immunosuppressive effect of hUC-MSCs in a dose-dependent fashion. Moreover, the inflammatory cytokine IL-1β, either exogenously added or produced by CD14 + monocytes in culture, could trigger expression of high levels of PGE 2 by hUC-MSCs, whereas inclusion of the IL-1 receptor antagonist (IL-1RA) in the culture down-regulated not only PGE 2 expression, but also reversed the promotional effect of CD14 + monocytes and partially restored CD4 + and CD8 + T cell proliferation and IFN-γ secretion. Our data demonstrate an important role of monocytes in the hUC-MSC-induced immunomodulation, which may have important implications in future efforts to explore the clinical potentials of hUC-MSCs.

A major protein component of the Bacillus subtilis biofilm matrix.

Science.gov (United States)

Branda, Steven S; Chu, Frances; Kearns, Daniel B; Losick, Richard; Kolter, Roberto

2006-02-01

Microbes construct structurally complex multicellular communities (biofilms) through production of an extracellular matrix. Here we present evidence from scanning electron microscopy showing that a wild strain of the Gram positive bacterium Bacillus subtilis builds such a matrix. Genetic, biochemical and cytological evidence indicates that the matrix is composed predominantly of a protein component, TasA, and an exopolysaccharide component. The absence of TasA or the exopolysaccharide resulted in a residual matrix, while the absence of both components led to complete failure to form complex multicellular communities. Extracellular complementation experiments revealed that a functional matrix can be assembled even when TasA and the exopolysaccharide are produced by different cells, reinforcing the view that the components contribute to matrix formation in an extracellular manner. Having defined the major components of the biofilm matrix and the control of their synthesis by the global regulator SinR, we present a working model for how B. subtilis switches between nomadic and sedentary lifestyles.

KinD is a checkpoint protein linking spore formation to extracellular-matrix production in Bacillus subtilis biofilms.

Science.gov (United States)

Aguilar, Claudio; Vlamakis, Hera; Guzman, Alejandra; Losick, Richard; Kolter, Roberto

2010-05-18

Bacillus subtilis cells form multicellular biofilm communities in which spatiotemporal regulation of gene expression occurs, leading to differentiation of multiple coexisting cell types. These cell types include matrix-producing and sporulating cells. Extracellular matrix production and sporulation are linked in that a mutant unable to produce matrix is delayed for sporulation. Here, we show that the delay in sporulation is not due to a growth advantage of the matrix-deficient mutant under these conditions. Instead, we show that the link between matrix production and sporulation is through the Spo0A signaling pathway. Both processes are regulated by the phosphorylated form of the master transcriptional regulator Spo0A. When cells have low levels of phosphorylated Spo0A (Spo0A~P), matrix genes are expressed; however, at higher levels of Spo0A~P, sporulation commences. We have found that Spo0A~P levels are maintained at low levels in the matrix-deficient mutant, thereby delaying expression of sporulation-specific genes. This is due to the activity of one of the components of the Spo0A phosphotransfer network, KinD. A deletion of kinD suppresses the sporulation defect of matrix mutants, while its overproduction delays sporulation. Our data indicate that KinD displays a dual role as a phosphatase or a kinase and that its activity is linked to the presence of extracellular matrix in the biofilms. We propose a novel role for KinD in biofilms as a checkpoint protein that regulates the onset of sporulation by inhibiting the activity of Spo0A until matrix, or a component therein, is sensed.

Corticotropin-Releasing Hormone (CRH Promotes Macrophage Foam Cell Formation via Reduced Expression of ATP Binding Cassette Transporter-1 (ABCA1.

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Wonkyoung Cho

Full Text Available Atherosclerosis, the major pathology of cardiovascular disease, is caused by multiple factors involving psychological stress. Corticotropin-releasing hormone (CRH, which is released by neurosecretory cells in the hypothalamus, peripheral nerve terminals and epithelial cells, regulates various stress-related responses. Our current study aimed to verify the role of CRH in macrophage foam cell formation, the initial critical stage of atherosclerosis. Our quantitative real-time reverse transcriptase PCR (qRT-PCR, semi-quantitative reverse transcriptase PCR, and Western blot results indicate that CRH down-regulates ATP-binding cassette transporter-1 (ABCA1 and liver X receptor (LXR-α, a transcription factor for ABCA1, in murine peritoneal macrophages and human monocyte-derived macrophages. Oil-red O (ORO staining and intracellular cholesterol measurement of macrophages treated with or without oxidized LDL (oxLDL and with or without CRH (10 nM in the presence of apolipoprotein A1 (apoA1 revealed that CRH treatment promotes macrophage foam cell formation. The boron-dipyrromethene (BODIPY-conjugated cholesterol efflux assay showed that CRH treatment reduces macrophage cholesterol efflux. Western blot analysis showed that CRH-induced down-regulation of ABCA1 is dependent on phosphorylation of Akt (Ser473 induced by interaction between CRH and CRH receptor 1(CRHR1. We conclude that activation of this pathway by CRH accelerates macrophage foam cell formation and may promote stress-related atherosclerosis.

Competitive Promoter-Associated Matrix Attachment Region Binding of the Arid3a and Cux1 Transcription Factors

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Dongkyoon Kim

2017-12-01

Full Text Available Arid3a/Bright/Dril1 is a B cell-specific transactivator that regulates immunoglobulin heavy chain (IgH gene transcription by binding promoter and enhancer-associated matrix attachment regions (MARs within the IgH gene locus. Promoter MAR-mediated Arid3a transactivation is antagonized by direct competition of MAR binding by Cux1/CDP—a ubiquitously expressed repressor originally termed NF-μNR. We report that the NF-μNR complex includes Arid3a in B cells but not in non-B cells through mobility shift assays. The binding activity of NF-μNR and Arid3a in B cells is reciprocally altered during the cell division cycle and by the B cell mitogen lipopolysaccharide LPS. LPS treatment had no effect on Arid3a localization but increased its total abundance within the nucleus and cytoplasm. We show that this increased level of Arid3a is capable of displacing Cux from the MARs to facilitate IgH gene transcription. Finally, we showed that the MARs (termed Bf150 and Tx125 associated with the VH1 rearranged variable region expressed in the S107 murine plasmacytoma, can repress reporter gene transcription in non-B cells and that they can relieve the repression mediated by Eμ enhancer in B cells. These results have significant implications for early human development and demonstrate that MARs in IgH locus, NF-µNR and Arid3a regulate IgH gene expression in a concerted fashion. This paves the way for future studies examining the misregulation of this pathway in pediatric disease.

Enhancement of polar crystalline phase formation in transparent PVDF-CaF{sub 2} composite films

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Goo; Ha, Jong-Wook, E-mail: jongwook@krict.re.kr; Sohn, Eun-Ho; Park, In Jun; Lee, Soo-Bok

2016-12-30

Highlights: • The crystalline phase in transparent PVDF-CaF{sub 2} composite films was investigated. • CaF{sub 2} promoted the formation of polar crystalline phases in PVDF matrix. • Ordered γ-phase was obtained by thermal treatment of as-cast films at the vicinity of its melting temperature. - Abstract: We consider the influence of calcium fluoride (CaF{sub 2}) nanoparticles on the crystalline phase formation of poly(vinylidene fluoride) (PVDF) for the first time. The transparent PVDF-CaF{sub 2} composite films were prepared by casting on PET substrates using N,N-dimethylacetamide (DMAc) as a solvent. It was found that CaF{sub 2} promoted the formation of polar crystalline phase of PVDF in composites, whereas nonpolar α-phase was dominant in the neat PVDF film prepared at the same condition. The portion of polar crystalline phase increased in proportional to the weight fraction of CaF{sub 2} in the composite films up to 10 wt%. Further addition of CaF{sub 2} suppressed completely the α-phase formation. Polar crystalline phase observed in as-cast composite films was a mixture of β- and γ-polymorph structures. It was also shown that much ordered γ-phase could be obtained through thermal treatment of as-cast PVDF-CaF{sub 2} composite film at the temperatures above the melting temperature of the composite films, but below that of γ-phase.

Improved success of sparse matrix protein crystallization screening with heterogeneous nucleating agents.

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Anil S Thakur

2007-10-01

Full Text Available Crystallization is a major bottleneck in the process of macromolecular structure determination by X-ray crystallography. Successful crystallization requires the formation of nuclei and their subsequent growth to crystals of suitable size. Crystal growth generally occurs spontaneously in a supersaturated solution as a result of homogenous nucleation. However, in a typical sparse matrix screening experiment, precipitant and protein concentration are not sampled extensively, and supersaturation conditions suitable for nucleation are often missed.We tested the effect of nine potential heterogenous nucleating agents on crystallization of ten test proteins in a sparse matrix screen. Several nucleating agents induced crystal formation under conditions where no crystallization occurred in the absence of the nucleating agent. Four nucleating agents: dried seaweed; horse hair; cellulose and hydroxyapatite, had a considerable overall positive effect on crystallization success. This effect was further enhanced when these nucleating agents were used in combination with each other.Our results suggest that the addition of heterogeneous nucleating agents increases the chances of crystal formation when using sparse matrix screens.

Overexpression of Catalase in Vascular Smooth Muscle Cells Prevents the Formation of Abdominal Aortic Aneurysms

Science.gov (United States)

Parastatidis, Ioannis; Weiss, Daiana; Joseph, Giji; Taylor, W Robert

2013-01-01

Objective Elevated levels of oxidative stress have been reported in abdominal aortic aneurysms (AAA), but which reactive oxygen species (ROS) promotes the development of AAA remains unclear. Here we investigate the effect of the hydrogen peroxide (H2O2) degrading enzyme catalase on the formation of AAA. Approach and Results AAA were induced with the application of calcium chloride (CaCl2) on mouse infrarenal aortas. The administration of PEG-catalase, but not saline, attenuated the loss of tunica media and protected against AAA formation (0.91±0.1 mm vs. 0.76±0.09 mm). Similarly, in a transgenic mouse model, catalase over-expression in the vascular smooth muscle cells (VSMC) preserved the thickness of tunica media and inhibited aortic dilatation by 50% (0.85±0.14 mm vs. 0.57±0.08 mm). Further studies showed that injury with CaCl2 decreased catalase expression and activity in the aortic wall. Pharmacologic administration or genetic over-expression of catalase restored catalase activity and subsequently decreased matrix metalloproteinase activity. In addition, a profound reduction in inflammatory markers and VSMC apoptosis was evident in aortas of catalase over-expressing mice. Interestingly, as opposed to infusion of PEG-catalase, chronic over-expression of catalase in VSMC did not alter the total aortic H2O2 levels. Conclusions The data suggest that a reduction in aortic wall catalase activity can predispose to AAA formation. Restoration of catalase activity in the vascular wall enhances aortic VSMC survival and prevents AAA formation primarily through modulation of matrix metalloproteinase activity. PMID:23950141

Self-Ordered Voids Formation in SiO2 Matrix by Ge Outdiffusion

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B. Pivac

2018-01-01

Full Text Available The annealing behavior of very thin SiO2/Ge multilayers deposited on Si substrate by e-gun deposition in high vacuum was explored. It is shown that, after annealing at moderate temperatures (800°C in inert atmosphere, Ge is completely outdiffused from the SiO2 matrix leaving small (about 3 nm spherical voids embedded in the SiO2 matrix. These voids are very well correlated and formed at distances governed by the preexisting multilayer structure (in vertical direction and self-organization (in horizontal direction. The formed films produce intensive photoluminescence (PL with a peak at 500 nm. The explored dynamics of the PL decay show the existence of a very rapid process similar to the one found at Ge/SiO2 defected interface layers.

EXPANSINA17 up-regulated by LBD18/ASL20 promotes lateral root formation during the auxin response.

Science.gov (United States)

Lee, Han Woo; Kim, Jungmook

2013-10-01

Expansins are non-hydrolytic cell wall-loosening proteins involved in a variety of plant developmental processes during which cell wall modification occurs. Cell wall remodeling proteins including expansins have been suggested to be involved in cell separation to facilitate the emergence of lateral roots (LRs) through the overlaying tissues of the primary root. LBD18/ASL20 activates EXPANSINA14 (EXPA14) expression by directly binding to the EXPA14 promoter to enhance LR emergence in Arabidopsis thaliana. Here we show that EXPA17 is another target gene regulated by LBD18 to promote LR formation in Arabidopsis. We showed that nuclear translocation of the LBD18:GR fusion protein expressed under the Cauliflower mosaic virus (CaMV) 35S promoter or under the LBD18 promoter by dexamethasone treatment results in an increase in EXPA17 transcript levels. β-Glucuronidase (GUS) expression under the EXPA17 promoter, which is detected only in the roots of the wild type, was reduced in the LR primordium and overlaying tissues in an lbd18 mutant background. The number of emerged LRs of the EXPA17 RNAi (RNA interference) Arabidopsis lines was significantly lower than that of the wild type. Overexpression of EXPA17 in Arabidopsis increased the density of emerged LRs in the presence of auxin compared with the wild type. LR induction experiments with a gravitropic stimulus showed that LR emergence is delayed in the EXPA17 RNAi plants compared with the wild type. In addition, EXPA4 expression was also detected in overlaying tissues of the LR primordium and was inducible by LBD18. Taken together, these results support the notion that LBD18 up-regulates a subset of EXP genes to enhance cell separation to promote LR emergence in Arabidopsis.

Stable Formation Control of Multi-Robot System with Communication Delay

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Limei Jiang

2012-03-01

Full Text Available In this paper, a distributed formation control algorithm with delayed information exchange is discussed. The algorithm, which is derived from the flocking behaviour of birds and consensus theory, enables robots to move in formation at a desired velocity. After a series of orthogonal transformations to the original formation system, the upper bound tolerable delay is obtained by using matrix theory and the Nyquist criterion. According to the results, the upper bound tolerable delay depends on the control parameters and eigenvalues of the Laplacian matrix. Therefore, the effect of the parameters on the maximum tolerable delay is analysed, obtaining the following conclusions: the upper bound tolerable delay is proportional to the parameters associated with the velocity, inversely proportional to the parameters associated with the position, and inversely proportional to the difference between the eigenvalue of Laplacian matrix and 1. The simulation results of a four-robot formation system with different communication delays verify the effectiveness of the formation control algorithm and the correctness of the theoretical analysis.

Sam37 is crucial for formation of the mitochondrial TOM-SAM supercomplex, thereby promoting β-barrel biogenesis.

Science.gov (United States)

Wenz, Lena-Sophie; Ellenrieder, Lars; Qiu, Jian; Bohnert, Maria; Zufall, Nicole; van der Laan, Martin; Pfanner, Nikolaus; Wiedemann, Nils; Becker, Thomas

2015-09-28

Biogenesis of mitochondrial β-barrel proteins requires two preprotein translocases, the general translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). TOM and SAM form a supercomplex that promotes transfer of β-barrel precursors. The SAM core complex contains the channel protein Sam50, which cooperates with Sam35 in precursor recognition, and the peripheral membrane protein Sam37. The molecular function of Sam37 has been unknown. We report that Sam37 is crucial for formation of the TOM-SAM supercomplex. Sam37 interacts with the receptor domain of Tom22 on the cytosolic side of the mitochondrial outer membrane and links TOM and SAM complexes. Sam37 thus promotes efficient transfer of β-barrel precursors to the SAM complex. We conclude that Sam37 functions as a coupling factor of the translocase supercomplex of the mitochondrial outer membrane. © 2015 Wenz et al.

Inhibition of the NLRP3 inflammasome attenuates foam cell formation of THP-1 macrophages by suppressing ox-LDL uptake and promoting cholesterol efflux.

Science.gov (United States)

Chen, Liang; Yao, Qiying; Xu, Siwei; Wang, Hongyan; Qu, Peng

2018-01-01

The NOD-like receptor family, pyrin domain-containing protein 3 (NLRP3) inflammasome plays an important role in the development of atherosclerosis. The activated NLRP3 inflammasome has been reported to promote macrophage foam cell formation, but not all studies have obtained the same result, and how NLRP3 inflammasome is involved in the formation of foam cells remains elusive. We used selective NLRP3 inflammasome inhibitors and NLRP3-deficient THP-1 cells to assess the effect of NLRP3 inflammasome inhibition on macrophage foam cell formation, oxidized low-density lipoprotein (ox-LDL) uptake, esterification, and cholesterol efflux, as well as the expression of associated proteins. Inhibition of the NLRP3 inflammasome attenuated foam cell formation, diminished ox-LDL uptake, and promoted cholesterol efflux from THP-1 macrophages. Moreover, it downregulated CD36, acyl coenzyme A: cholesterol acyltransferase-1 and neutral cholesterol ester hydrolase expression; upregulated ATP-binding cassette transporter A1 (ABCA1) and scavenger receptor class B type I (SR-BI) expression; but had no effect on the expression of scavenger receptor class A and ATP-binding cassette transporter G1. Collectively, our findings show that inhibition of the NLRP3 inflammasome decreases foam cell formation of THP-1 macrophages via suppression of ox-LDL uptake and enhancement of cholesterol efflux, which may be due to downregulation of CD36 expression and upregulation of ABCA1 and SR-BI expression, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

Ejection of matrix-polymer clusters in matrix-assisted laser evaporation: Experimental observations

International Nuclear Information System (INIS)

Sellinger, Aaron T; Leveugle, Elodie; Gogick, Kristy; Peman, Guillaume; Zhigilei, Leonid V; Fitz-Gerald, James M

2007-01-01

The morphology of polymer films deposited with the matrix-assisted pulsed laser evaporation (MAPLE) technique is explored for various target compositions and laser fluences. Composite targets of 1 to 5 wt.% poly(methyl methacrylate), PMMA, dissolved in a volatile matrix material, toluene, were ablated using an excimer laser at fluences ranging from 0.045 J/cm 2 to 0.75 J/cm 2 . Films were deposited on Si substrates at room temperature in a dynamic 100 mTorr Ar atmosphere. Scanning electron microscopy (SEM) imaging revealed that the morphology of the deposited films varied significantly with both laser fluence and PMMA concentration. The morphologies of large deposited particles were similar to that of deflated ''balloons''. It is speculated that during ablation of the frozen target, clusters comprised of both polymer and solvent ranging from 100 nm to 10 μm in size are ejected and deposited onto the substrate. The solvent begins to evaporate from the clusters during flight from the target, but does not completely evaporate until deposited on the room temperature substrate. The dynamics of the toluene evaporation may lead to the formation of the deflated structures. This explanation is supported by the observation of stable polymer-matrix droplets ejected in molecular dynamics simulations of MAPLE

Strategy BMT Al-Ittihad Using Matrix IE, Matrix SWOT 8K, Matrix SPACE and Matrix TWOS

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Nofrizal Nofrizal

2018-03-01

Full Text Available This research aims to formulate and select BMT Al-Ittihad Rumbai strategy to face the changing of business environment both from internal environment such as organization resources, finance, member and external business such as competitor, economy, politics and others. This research method used Analysis of EFAS, IFAS, IE Matrix, SWOT-8K Matrix, SPACE Matrix and TWOS Matrix. our hope from this research it can assist BMT Al-Ittihad in formulating and selecting strategies for the sustainability of BMT Al-Ittihad in the future. The sample in this research is using purposive sampling technique that is the manager and leader of BMT Al-IttihadRumbaiPekanbaru. The result of this research shows that the position of BMT Al-Ittihad using IE Matrix, SWOT-8K Matrix and SPACE Matrix is in growth position, stabilization and aggressive. The choice of strategy after using TWOS Matrix is market penetration, market development, vertical integration, horizontal integration, and stabilization (careful.

Different matrix micro-environments in colon cancer and diverticular disease.

Science.gov (United States)

Klinge, U; Rosch, R; Junge, K; Krones, C J; Stumpf, M; Lynen-Jansen, P; Mertens, P R; Schumpelick, V

2007-05-01

The extracellular matrix and the interactive signalling between its components are thought to play a pivotal role for tumour development and metastasis formation. An altered matrix composition as potential underlying pathology for the development of colorectal cancer was hypothesized. In a retrospective study of patients with colon cancer, the extracellular matrix in tumour-free bowel specimen was investigated in comparison with non-infected bowel specimen from patients operated on for colonic diverticulosis. The following matrix parameters with known associations to tumour formation, cell proliferation, invasion and metastasis were analysed by immunohistochemistry and quantified by a scoring system: VEGF, TGF-beta, ESDN, CD117, c-erb-2, cyclin D1, p53, p27, COX-2, YB-1, collagen I/III, MMP-13, PAI and uPAR. Expression profiles and correlations were calculated. The comparison of the two groups revealed a significantly decreased immunostaining for CD117 and TGF-beta in the cancer group (8.5+/-2.6 vs 10.3+/-2,1 and 4.9+/-1.5 vs 8.1+/-3, respectively), whereas PAI scores were significantly higher than in patients with diverticular disease (8.1+/-1.6 vs 6.2+/-0.9). Overall correlation patterns of matrix parameters indicated pronounced differences between tumour-free tissue in cancer patients compared with patients with diverticular disease. Our results indicate distinct differences in the colonic tissue architecture between cancer patients and patients with diverticulitis that support the notion of an altered matrix composition predisposing to the development of colon cancer.

"Tipping" extracellular matrix remodeling towards regression of liver fibrosis

DEFF Research Database (Denmark)

Magdaleno, Fernando; Schierwagen, Robert; Uschner, Frank E

2018-01-01

Fibrosis development was initially conceived as an incessant progressive condition. Nowadays, it has become evident that fibrotic tissue undergoes a continuous two-way process: fibrogenesis and fibrinolysis, characterizing the remodeling of extracellular matrix (ECM). However, in established...... fibrosis, this two-way process is tipped towards fibrogenesis and this leads to a self-perpetuating accumulation of ECM, a distinct metabolic unit, together with other cells and processes promoting fibrosis deposition. Several mechanisms promote fibrosis regression, such as degradation of ECM, infiltration...

The secreted protein ANGPTL2 promotes metastasis of osteosarcoma cells through integrin α5β1, p38 MAPK, and matrix metalloproteinases.

Science.gov (United States)

Odagiri, Haruki; Kadomatsu, Tsuyoshi; Endo, Motoyoshi; Masuda, Tetsuro; Morioka, Masaki Suimye; Fukuhara, Shigetomo; Miyamoto, Takeshi; Kobayashi, Eisuke; Miyata, Keishi; Aoi, Jun; Horiguchi, Haruki; Nishimura, Naotaka; Terada, Kazutoyo; Yakushiji, Toshitake; Manabe, Ichiro; Mochizuki, Naoki; Mizuta, Hiroshi; Oike, Yuichi

2014-01-21

The tumor microenvironment can enhance the invasive capacity of tumor cells. We showed that expression of angiopoietin-like protein 2 (ANGPTL2) in osteosarcoma (OS) cell lines increased and the methylation of its promoter decreased with time when grown as xenografts in mice compared with culture. Compared with cells grown in normal culture conditions, the expression of genes encoding DNA demethylation-related enzymes increased in tumor cells implanted into mice or grown in hypoxic, serum-starved culture conditions. ANGPTL2 expression in OS cell lines correlated with increased tumor metastasis and decreased animal survival by promoting tumor cell intravasation mediated by the integrin α5β1, p38 mitogen-activated protein kinase, and matrix metalloproteinases. The tolloid-like 1 (TLL1) protease cleaved ANGPTL2 into fragments in vitro that did not enhance tumor progression when overexpressed in xenografts. Expression of TLL1 was weak in OS patient tumors, suggesting that ANGPTL2 may not be efficiently cleaved upon secretion from OS cells. These findings demonstrate that preventing ANGPTL2 signaling stimulated by the tumor microenvironment could inhibit tumor cell migration and metastasis.

Comprehensive profiling and localisation of the matrix metalloproteinases in urothelial carcinoma

OpenAIRE

Wallard, M J; Pennington, C J; Veerakumarasivam, A; Burtt, G; Mills, I G; Warren, A; Leung, H Y; Murphy, G; Edwards, D R; Neal, D E; Kelly, J D

2006-01-01

The matrix metalloproteinases (MMPs) are endopeptidases which break down the extracellular matrix and regulate cytokine and growth factor activity. Several MMPs have been implicated in the promotion of invasion and metastasis in a broad range of tumours including urothelial carcinoma. In this study, RNA from 132 normal bladder and urothelial carcinoma specimens was profiled for each of the 24 human MMPs, the four endogenous tissue inhibitors of MMPs (TIMPs) and several key growth factors and ...

Structure and decomposition of the silver formate Ag(HCO2)

International Nuclear Information System (INIS)

Puzan, Anna N.; Baumer, Vyacheslav N.; Mateychenko, Pavel V.

2017-01-01

Crystal structure of the silver formate Ag(HCO 2 ) has been determined (orthorhombic, sp.gr. Pccn, a=7.1199(5), b=10.3737(4), c=6.4701(3)Å, V=477.88(4) Å 3 , Z=8). The structure contains isolated formate ions and the pairs Ag 2 2+ which form the layers in (001) planes (the shortest Ag–Ag distances is 2.919 in the pair and 3.421 and 3.716 Å between the nearest Ag atoms of adjacent pairs). Silver formate is unstable compound which decompose spontaneously vs time. Decomposition was studied using Rietveld analysis of the powder diffraction patterns. It was concluded that the diffusion of Ag atoms leads to the formation of plate-like metal particles as nuclei in the (100) planes which settle parallel to (001) planes of the silver formate matrix. - Highlights: • Silver formate Ag(HCO 2 ) was synthesized and characterized. • Layered packing of Ag-Ag pairs in the structure was found. • Decomposition of Ag(HCO 2 ) and formation of metal phase were studied. • Rietveld-refined micro-structural characteristics during decomposition reveal the space relationship between the matrix structure and forming Ag phase REPLACE with: Space relationship between the matrix structure and forming Ag phase.

The immobilized NaHSO4·H2O on activated charcoal: a highly efficient promoter system for N-formylation of amines with ethyl formate

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Behzad Zeynizadeh

2016-03-01

Full Text Available The immobilized NaHSO4·H2O on activated charcoal was used as a highly efficient promoter system for facile N-formylation of amines with ethyl formate. All reactions were carried out in refluxing ethyl formate (54 ºC under mild conditions within 10-100 min to afford the product formamides in high to excellent yields (80-94%.

 The role of metalloproteinases in modification of extracellular matrix in invasive tumor growth, metastasis and angiogenesis

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Krzysztof Fink

2012-09-01

Full Text Available Extracellular matrix metalloproteinases (MMPs are a family of endopeptydases which recquire a zinc ion at their active site, for proteolityc activity. There are six members of the MMP family: matrilysins, collagenases, stromelysins, gelatinases, membrane MMPs and other MMPs. Activity of MMPs is regulated at the level of gene transcription, mRNA stability, zymogene proteolitic activation, inhibition of an active enzyme and MMP degradation. Tissue inhibitors of metalloproteinases (TIMPs are main intracellular inhibitors of MMPs. Host cells can be stimulated by tumor cells to produce MMPs by secreted interleukins, interferons, growth factors and an extracellular matrix metalloproteinase inducer (EMMPRIN. MMPs are produced by tumor cells, fibroblasts, macrophages, mast cells, polimorphonuclear neutrophiles (PMNs and endothelial cells (ECs. MMPs affect many stages of tumor development, facilitating its growth through promoting tumor cells proliferation, invasion and migration, new blood vessels formation and blocking tumor cells apoptosis. MMPs can promote tumor development in several ways. ECM degradation results in release of peptide growth factors. Growth factors linked with cell surface or binding proteins can also be liberated by MMPs. MMPs can indirectly regulate integrin signalling or cleave E-cadherins, facilitating cell migration. MMPs support metastasis inducing an epithelial to mesenchymal transition (EMT. MMP also support transendothelial migration. MMPs support angiogenesis by releasing pro-angiogenic factors and degrading ECM to support ECs migration. Cell surface growth factor receptors are also cleaved by MMPs, which results in inhibition of tumor development, so is release of anti-angiogenic factors from ECM. 

The hemostatic agent ethamsylate promotes platelet/leukocyte aggregate formation in a model of vascular injury.

Science.gov (United States)

Hernandez, Maria Rosa; Alvarez-Guerra, Miriam; Escolar, Ginés; Chiavaroli, Carlo; Hannaert, Patrick; Garay, Ricardo P

2004-08-01

The hemostatic agent ethamsylate enhances membrane expression of P-selectin in human platelets, but whether this promotes platelet-leukocyte aggregate formation is unknown. Here we investigated this point by flow cytometry determination of human platelet-leukocyte aggregates under basal conditions and after whole-blood perfusion through a damaged rabbit aorta segment. Actions of ethamsylate on adhesive molecules of platelets and leukocytes were investigated in parallel. Under basal conditions, ethamsylate was unable to modify whole-blood platelet-leukocyte aggregation, but following whole-blood perfusion through a damaged vessel, ethamsylate produced a modest, but significant increase in platelet-leukocyte aggregates (48+/-21 and 45+/-26% above control levels at ethamsylate 20 and 40 microm respectively). In isolated leukocyte plasma membranes, 14C-ethamsylate specifically bound up to an amount of 660 pmol/mg protein. Moreover, at concentrations > or =1 microm, ethamsylate induced an important (100-200%) and significant increase in the P-selectin glycoprotein ligand 1 (PSGL-1) fluorescence signal in isolated leukocytes and was unable to significantly modify the percentage of CD11b-positive cells. However, no significant changes in aggregate formation were found when ethamsylate was incubated with isolated leukocytes and blood was reconstituted and perfused. In isolated platelet cell membranes, anti-P-selectin antibody and the anti-integrin RGD-containing pentapeptide (GRDGS) were unable to displace 14C-ethamsylate binding. In conclusion, ethamsylate specifically binds to plasma membranes of leukocytes, enhances membrane PSGL-1 expression and promotes leukocyte-platelet aggregation in whole-blood perfused through a damaged vascular segment. These results together with the previously observed enhancement of platelet P-selectin membrane expression [Thromb. Res. (2002)107:329-335] confirms and extends the view that ethamsylate acts on the first step of hemostasis, by

PrP P102L and Nearby Lysine Mutations Promote Spontaneous In Vitro Formation of Transmissible Prions.

Science.gov (United States)

Kraus, Allison; Raymond, Gregory J; Race, Brent; Campbell, Katrina J; Hughson, Andrew G; Anson, Kelsie J; Raymond, Lynne D; Caughey, Byron

2017-11-01

Accumulation of fibrillar protein aggregates is a hallmark of many diseases. While numerous proteins form fibrils by prion-like seeded polymerization in vitro , only some are transmissible and pathogenic in vivo To probe the structural features that confer transmissibility to prion protein (PrP) fibrils, we have analyzed synthetic PrP amyloids with or without the human prion disease-associated P102L mutation. The formation of infectious prions from PrP molecules in vitro has required cofactors and/or unphysiological denaturing conditions. Here, we demonstrate that, under physiologically compatible conditions without cofactors, the P102L mutation in recombinant hamster PrP promoted prion formation when seeded by minute amounts of scrapie prions in vitro Surprisingly, combination of the P102L mutation with charge-neutralizing substitutions of four nearby lysines promoted spontaneous prion formation. When inoculated into hamsters, both of these types of synthetic prions initiated substantial accumulation of prion seeding activity and protease-resistant PrP without transmissible spongiform encephalopathy (TSE) clinical signs or notable glial activation. Our evidence suggests that PrP's centrally located proline and lysine residues act as conformational switches in the in vitro formation of transmissible PrP amyloids. IMPORTANCE Many diseases involve the damaging accumulation of specific misfolded proteins in thread-like aggregates. These threads (fibrils) are capable of growing on the ends by seeding the refolding and incorporation of the normal form of the given protein. In many cases such aggregates can be infectious and propagate like prions when transmitted from one individual host to another. Some transmitted aggregates can cause fatal disease, as with human iatrogenic prion diseases, while other aggregates appear to be relatively innocuous. The factors that distinguish infectious and pathogenic protein aggregates from more innocuous ones are poorly understood

Filamin A Mediates Wound Closure by Promoting Elastic Deformation and Maintenance of Tension in the Collagen Matrix

Science.gov (United States)

Mohammadi, Hamid; Pinto, Vanessa I.; Wang, Yongqiang; Hinz, Boris; Janmey, Paul A.; McCulloch, Christopher A.

2016-01-01

Cell-mediated remodeling and wound closure are critical for efficient wound healing, but the contribution of actin-binding proteins to contraction of the extracellular matrix is not defined. We examined the role of filamin A (FLNa), an actin filament cross-linking protein, in wound contraction and maintenance of matrix tension. Conditional deletion of FLNa in fibroblasts in mice was associated with ~ 4 day delay of full-thickness skin wound contraction compared with wild-type (WT) mice. We modeled the healing wound matrix using cultured fibroblasts plated on grid-supported collagen gels that create lateral boundaries, which are analogues to wound margins. In contrast to WT cells, FLNa knockdown (KD) cells could not completely maintain tension when matrix compaction was resisted by boundaries, which manifested as relaxed matrix tension. Similarly, WT cells on cross-linked collagen, which requires higher levels of sustained tension, exhibited approximately fivefold larger deformation fields and approximately twofold greater fiber alignment compared with FLNa KD cells. Maintenance of boundary-resisted tension markedly influenced the elongation of cell extensions: in WT cells, the number (~50%) and length (~300%) of cell extensions were greater than FLNa KD cells. We conclude that FLNa is required for wound contraction, in part by enabling elastic deformation and maintenance of tension in the matrix. PMID:26134946

TNF-α promotes human retinal pigment epithelial (RPE) cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression through activation of Akt/mTORC1 signaling

International Nuclear Information System (INIS)

Wang, Cheng-hu; Cao, Guo-Fan; Jiang, Qin; Yao, Jin

2012-01-01

Highlights: ► TNF-α induces MMP-9 expression and secretion to promote RPE cell migration. ► MAPK activation is not critical for TNF-α-induced MMP-9 expression. ► Akt and mTORC1 signaling mediate TNF-α-induced MMP-9 expression. ► SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-α. -- Abstract: Tumor necrosis factor-alpha (TNF-α) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-α promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-α-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-α-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-α promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.

TNF-{alpha} promotes human retinal pigment epithelial (RPE) cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression through activation of Akt/mTORC1 signaling

Energy Technology Data Exchange (ETDEWEB)

Wang, Cheng-hu; Cao, Guo-Fan [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Jiang, Qin, E-mail: Jqin710@vip.sina.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Yao, Jin, E-mail: dryaojin@yahoo.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China)

2012-08-17

Highlights: Black-Right-Pointing-Pointer TNF-{alpha} induces MMP-9 expression and secretion to promote RPE cell migration. Black-Right-Pointing-Pointer MAPK activation is not critical for TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer Akt and mTORC1 signaling mediate TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-{alpha}. -- Abstract: Tumor necrosis factor-alpha (TNF-{alpha}) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-{alpha} promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-{alpha}-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-{alpha}-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-{alpha} promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.

A Candida biofilm-induced pathway for matrix glucan delivery: implications for drug resistance.

Directory of Open Access Journals (Sweden)

Heather T Taff

Full Text Available Extracellular polysaccharides are key constituents of the biofilm matrix of many microorganisms. One critical carbohydrate component of Candida albicans biofilms, β-1,3 glucan, has been linked to biofilm protection from antifungal agents. In this study, we identify three glucan modification enzymes that function to deliver glucan from the cell to the extracellular matrix. These enzymes include two predicted glucan transferases and an exo-glucanase, encoded by BGL2, PHR1, and XOG1, respectively. We show that the enzymes are crucial for both delivery of β-1,3 glucan to the biofilm matrix and for accumulation of mature matrix biomass. The enzymes do not appear to impact cell wall glucan content of biofilm cells, nor are they necessary for filamentation or biofilm formation. We demonstrate that mutants lacking these genes exhibit enhanced susceptibility to the commonly used antifungal, fluconazole, during biofilm growth only. Transcriptional analysis and biofilm phenotypes of strains with multiple mutations suggest that these enzymes act in a complementary fashion to distribute matrix downstream of the primary β-1,3 glucan synthase encoded by FKS1. Furthermore, our observations suggest that this matrix delivery pathway works independently from the C. albicans ZAP1 matrix formation regulatory pathway. These glucan modification enzymes appear to play a biofilm-specific role in mediating the delivery and organization of mature biofilm matrix. We propose that the discovery of inhibitors for these enzymes would provide promising anti-biofilm therapeutics.

Monosodium Urate in the Presence of RANKL Promotes Osteoclast Formation through Activation of c-Jun N-Terminal Kinase

Directory of Open Access Journals (Sweden)

Jung-Yoon Choe

2015-01-01

Full Text Available The aim of this study was to clarify the role of monosodium urate (MSU crystals in receptor activator of nuclear factor kB ligand- (RANKL- RANK-induced osteoclast formation. RAW 264.7 murine macrophage cells were incubated with MSU crystals or RANKL and differentiated into osteoclast-like cells as confirmed by staining for tartrate-resistant acid phosphatase (TRAP and actin ring, pit formation assay, and TRAP activity assay. MSU crystals in the presence of RANKL augmented osteoclast differentiation, with enhanced mRNA expression of NFATc1, cathepsin K, carbonic anhydrase II, and matrix metalloproteinase-9 (MMP-9, in comparison to RAW 264.7 macrophages incubated in the presence of RANKL alone. Treatment with both MSU crystals and RANKL induced osteoclast differentiation by activating downstream molecules in the RANKL-RANK pathway including tumor necrosis factor receptor-associated factor 6 (TRAF-6, JNK, c-Jun, and NFATc1. IL-1b produced in response to treatment with both MSU and RANKL is involved in osteoclast differentiation in part through the induction of TRAF-6 downstream of the IL-1b pathway. This study revealed that MSU crystals contribute to enhanced osteoclast formation through activation of RANKL-mediated pathways and recruitment of IL-1b. These findings suggest that MSU crystals might be a pathologic causative agent of bone destruction in gout.

β1 integrin signaling promotes neuronal migration along vascular scaffolds in the post-stroke brain

Directory of Open Access Journals (Sweden)

Teppei Fujioka

2017-02-01

Full Text Available Cerebral ischemic stroke is a main cause of chronic disability. However, there is currently no effective treatment to promote recovery from stroke-induced neurological symptoms. Recent studies suggest that after stroke, immature neurons, referred to as neuroblasts, generated in a neurogenic niche, the ventricular-subventricular zone, migrate toward the injured area, where they differentiate into mature neurons. Interventions that increase the number of neuroblasts distributed at and around the lesion facilitate neuronal repair in rodent models for ischemic stroke, suggesting that promoting neuroblast migration in the post-stroke brain could improve efficient neuronal regeneration. To move toward the lesion, neuroblasts form chain-like aggregates and migrate along blood vessels, which are thought to increase their migration efficiency. However, the molecular mechanisms regulating these migration processes are largely unknown. Here we studied the role of β1-class integrins, transmembrane receptors for extracellular matrix proteins, in these migrating neuroblasts. We found that the neuroblast chain formation and blood vessel-guided migration critically depend on β1 integrin signaling. β1 integrin facilitated the adhesion of neuroblasts to laminin and the efficient translocation of their soma during migration. Moreover, artificial laminin-containing scaffolds promoted neuroblast chain formation and migration toward the injured area. These data suggest that laminin signaling via β1 integrin supports vasculature-guided neuronal migration to efficiently supply neuroblasts to injured areas. This study also highlights the importance of vascular scaffolds for cell migration in development and regeneration.

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

International Nuclear Information System (INIS)

Zhang, Bingyu; Luo, Qing; Mao, Xinjian; Xu, Baiyao; Yang, Li; Ju, Yang; Song, Guanbin

2014-01-01

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

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

The Microbial Efficiency-Matrix Stabilization (MEMS) framework integrates plant litter decomposition with soil organic matter stabilization: do labile plant inputs form stable soil organic matter?

Science.gov (United States)

Cotrufo, M Francesca; Wallenstein, Matthew D; Boot, Claudia M; Denef, Karolien; Paul, Eldor

2013-04-01

The decomposition and transformation of above- and below-ground plant detritus (litter) is the main process by which soil organic matter (SOM) is formed. Yet, research on litter decay and SOM formation has been largely uncoupled, failing to provide an effective nexus between these two fundamental processes for carbon (C) and nitrogen (N) cycling and storage. We present the current understanding of the importance of microbial substrate use efficiency and C and N allocation in controlling the proportion of plant-derived C and N that is incorporated into SOM, and of soil matrix interactions in controlling SOM stabilization. We synthesize this understanding into the Microbial Efficiency-Matrix Stabilization (MEMS) framework. This framework leads to the hypothesis that labile plant constituents are the dominant source of microbial products, relative to input rates, because they are utilized more efficiently by microbes. These microbial products of decomposition would thus become the main precursors of stable SOM by promoting aggregation and through strong chemical bonding to the mineral soil matrix. © 2012 Blackwell Publishing Ltd.

Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations.

Science.gov (United States)

Esteve-Altava, Borja; Rasskin-Gutman, Diego

2014-09-01

Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articulations, we have built a network null model of the skull that simulates unconstrained bone growth. This null model predicts bone articulations that arise due to a process of bone growth that is uniform in rate, direction and timing. By comparing predicted articulations with the actual bone articulations of the human skull, we have identified which boundaries specifically need the presence of functional matrices for their formation. We show that functional matrices are necessary to connect facial bones, whereas an unconstrained bone growth is sufficient to connect non-facial bones. This finding challenges the role of the brain in the formation of boundaries between bones in the braincase without neglecting its effect on skull shape. Ultimately, our null model suggests where to look for modified developmental mechanisms promoting changes in bone growth patterns that could affect the development and evolution of the head skeleton. © 2014 Anatomical Society.

Another Face of the Hero: "The Matrix" as Modern Hero-Quest.

Science.gov (United States)

Stroud, Scott R.

This paper analyzes the interesting narrative structure of the hero-quest myth contained within the 1999 film, "The Matrix," and explicates the implications of this message upon the audience. Initially, the relevance of myth to movies and the format of Joseph Campbell's hero-quest is illustrated. This format is then applied to "The…

Matrix stiffness reverses the effect of actomyosin tension on cell proliferation.

Science.gov (United States)

Mih, Justin D; Marinkovic, Aleksandar; Liu, Fei; Sharif, Asma S; Tschumperlin, Daniel J

2012-12-15

The stiffness of the extracellular matrix exerts powerful effects on cell proliferation and differentiation, but the mechanisms transducing matrix stiffness into cellular fate decisions remain poorly understood. Two widely reported responses to matrix stiffening are increases in actomyosin contractility and cell proliferation. To delineate their relationship, we modulated cytoskeletal tension in cells grown across a physiological range of matrix stiffnesses. On both synthetic and naturally derived soft matrices, and across a panel of cell types, we observed a striking reversal of the effect of inhibiting actomyosin contractility, switching from the attenuation of proliferation on rigid substrates to the robust promotion of proliferation on soft matrices. Inhibiting contractility on soft matrices decoupled proliferation from cytoskeletal tension and focal adhesion organization, but not from cell spread area. Our results demonstrate that matrix stiffness and actomyosin contractility converge on cell spreading in an unexpected fashion to control a key aspect of cell fate.

Nanoindentation studies of ex situ AlN/Al metal matrix nanocomposites

International Nuclear Information System (INIS)

Fale, Sandeep; Likhite, Ajay; Bhatt, Jatin

2014-01-01

Highlights: • Formation of in-situ phases nucleated on AlN particles strengthens the matrix. • Formation of in-situ phases increases with AlN content in nanocomposites. • Stronger in-situ phases results in increased hardness and modulus of elasticity. - Abstract: Nanocrystalline Aluminium nitride (AlN) powder is dispersed in different weight ratio in Aluminum matrix to fabricate metal matrix nanocomposite (MMNC) using ex situ melt metallurgy process. The synthesized Al–AlN nanocomposites are studied for phase analysis using high resolution scanning electron microscopy (FEG-SEM) and for hardness behavior using microindentation and nanoindentation tests. Quantitative analysis of the oxide phases is calculated from thermodynamic data and mass balance equation using elemental data obtained from energy dispersive spectroscopy (EDS) results. Role of oxide phases in association with AlN particles is investigated to understand the mechanical behavior of composites using nanoindentation tester. Load–displacement profile obtained from nanoindentation test reveals distribution of oxide phases along with AlN particle and their effect on indent penetration

Impact of matrix size on observer performance in digital chest radiography

International Nuclear Information System (INIS)

Koelblinger, C.

2003-02-01

This thesis compared the observer performance in the detection of abnormalities on 2k matrix(0,2 mm pixel size) and 4k matrix (0,1 mm pixel size) digital chest radiographs. Eighty five patients who underwent CT of the thorax were prospectively reccruited into the study. A chest x-ray of each patient was acquired in 2k and 4k format and four readers analyzed the images by different criterias. On the one hand a ROC analysis was performed with the CT data as goldstandard. On the other hand each reader had to rate different anatomical structures in a direct comparison of the pictures. The results of the ratings did not show any significant difference between the 2k and the 4k format. The conclusion or this study is that the use of a 4k instead of a 2k matrix in digital chest radiography does not yield to an improved observer performance. (author)

Circulating levels of matrix metalloproteinases and tissue inhibitors of metalloproteinases in patients with incisional hernia

DEFF Research Database (Denmark)

Henriksen, Nadia A; Sørensen, Lars T; Jorgensen, Lars N

2013-01-01

Incisional hernia formation is a common complication to laparotomy and possibly associated with alterations in connective tissue metabolism. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are closely involved in the metabolism of the extracellular matrix. Our...

Formation and vibrational structure of Si nano-clusters in ZnO matrix

Energy Technology Data Exchange (ETDEWEB)

Garcia-Serrano, J. [Universidad Autonoma del Estado de Hidalgo, Hidalgo (Mexico); Pal, U. [Universidad Autonoma de Puebla, Puebla (Mexico); Koshizaki, N.; Sasaki, T. [National Institute of Materials and Chemical Research, Ibaraki (Japan)

2001-02-01

We have studied the formation and vibrational structure of Si nano-clusters in ZnO matrix prepared by radio-frequency (r.f.) co-sputtering, and characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and Infrared (IR) spectroscopy techniques. The composite films of Si/ZnO were grown o quartz substrates by co-sputtering of Si and ZnO targets. TEM images show a homogeneous distribution of clusters in the matrix with average size varied from 3.7 nm to 34 nm depending on the temperature of annealing. IR absorption measurements revealed the bands correspond to the modes of vibrations of Si{sub 3} in its triangular geometrical structure. By analysing the IR absorption and XPS spectra we found that the nano-clusters consist of a Si{sub 3} core and a SiO{sub x} cap layer. With the increase of annealing temperature, the vibrational states of Si changed from the triplet {sup 3}B1(C2{sub v}) and {sup 3}A'{sub 2}(D{sub 3h}) states to its singlet ground state {sup 1}A{sub 1}(C2{sub v}) and the oxidation state of Si in SiO{sub x} increased. The evolution of the local atomic structure of the Si nano-clusters with the variation of Si content in the film and with the variation of the temperature of annealing are discussed. [Spanish] Se estudia la formacion y estructura vibracional de nano-cumulos de Si en matriz de ZnO preparados por la tecnica de radio-frecuencia (r.f.) co-sputtering, y caracterizados por Microscopia Electronica de Transmision (TEM), Espectroscopia Fotoelectronica de rayos X (XPS) y Espectroscopia de Infrarrojo (IR). Las peliculas compositas de Si/ZnO fueron crecidas sobre sustratos de cuarzo mediante el co-sputtering de blancos de Si y ZnO. Las imagenes de TEM mostraron una distribucion homogenea de cumulos en la matriz con un tamano promedio de 3.7 nm a 34 nm dependiendo de la temperatura de tratamiento. Las mediciones de IR relevaron las bandas correspondientes a los modos de vibracion de Si{sub 3} en su estructura

Oxidation behaviour of cast aluminium matrix composites with Ce surface coatings

International Nuclear Information System (INIS)

Pardo, A.; Merino, M.C.; Arrabal, R.; Feliu, S.; Viejo, F.

2007-01-01

The oxidation behaviour of SiC-reinforced aluminium matrix composites (A3xx.x/SiCp) has been studied after Ce-based treatments. Kinetics data of oxidation process were obtained from gravimetric tests performed at different temperatures (350, 425 and 500 o C). The nature of the oxidation layer was analyzed by scanning electron and atomic force microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. The extent of oxidation degradation in untreated composites was preferentially localized in matrix/SiCp interfaces favouring the MgO formation. Ce coatings favoured a uniform oxidation of the composite surface with MgAl 2 O 4 spinel formation. This oxide increased the surface hardness of the materials

Alpinumisoflavone and abyssinone V 4'-methylether derived from Erythrina lysistemon (Fabaceae) promote HDL-cholesterol synthesis and prevent cholesterol gallstone formation in ovariectomized rats.

Science.gov (United States)

Mvondo, Marie A; Njamen, Dieudonné; Kretzschmar, Georg; Imma Bader, Manuela; Tanee Fomum, Stephen; Wandji, Jean; Vollmer, Günter

2015-07-01

Erythrina lysistemon was found to improve lipid profile in ovariectomized rats. Alpinumisoflavone (AIF) and abyssinone V 4'-methylether (AME) derived from this plant induced analogous effects on lipid profile and decreased atherogenic risks. To highlight the molecular mechanism of action of these natural products, we evaluated their effects on the expression of some estrogen-sensitive genes associated with cholesterol synthesis (Esr1 and Apoa1) and cholesterol clearance (Ldlr, Scarb1 and Cyp7a1). Ovariectomized rats were subcutaneously treated for three consecutive days with either compound at the daily dose of 0.1, 1 and 10 mg/kg body weight (BW). Animals were sacrificed thereafter and their liver was collected. The mRNA of genes of interest was analysed by quantitative real-time polymerase chain reaction. Both compounds downregulated the mRNA expression of Esr1, a gene associated with cholesterogenesis and cholesterol gallstone formation. AME leaned the Apoa1/Scarb1 balance in favour of Apoa1, an effect promoting high-density lipoprotein (HDL)-cholesterol formation. It also upregulated the mRNA expression of Ldlr at 1 mg/kg/BW per day (25%) and 10 mg/kg/BW per day (133.17%), an effect favouring the clearance of low-density lipoprotein (LDL)-cholesterol. Both compounds may also promote the conversion of cholesterol into bile acids as they upregulated Cyp7a1 mRNA expression. AIF and AME atheroprotective effects may result from their ability to upregulate mechanisms promoting HDL-cholesterol and bile acid formation. © 2015 Royal Pharmaceutical Society.

Cell-mediated fibre recruitment drives extracellular matrix mechanosensing in engineered fibrillar microenvironments

Science.gov (United States)

Baker, Brendon M.; Trappmann, Britta; Wang, William Y.; Sakar, Mahmut S.; Kim, Iris L.; Shenoy, Vivek B.; Burdick, Jason A.; Chen, Christopher S.

2015-12-01

To investigate how cells sense stiffness in settings structurally similar to native extracellular matrices, we designed a synthetic fibrous material with tunable mechanics and user-defined architecture. In contrast to flat hydrogel surfaces, these fibrous materials recapitulated cell-matrix interactions observed with collagen matrices including stellate cell morphologies, cell-mediated realignment of fibres, and bulk contraction of the material. Increasing the stiffness of flat hydrogel surfaces induced mesenchymal stem cell spreading and proliferation; however, increasing fibre stiffness instead suppressed spreading and proliferation for certain network architectures. Lower fibre stiffness permitted active cellular forces to recruit nearby fibres, dynamically increasing ligand density at the cell surface and promoting the formation of focal adhesions and related signalling. These studies demonstrate a departure from the well-described relationship between material stiffness and spreading established with hydrogel surfaces, and introduce fibre recruitment as a previously undescribed mechanism by which cells probe and respond to mechanics in fibrillar matrices.

Universal shocks in the Wishart random-matrix ensemble.

Science.gov (United States)

Blaizot, Jean-Paul; Nowak, Maciej A; Warchoł, Piotr

2013-05-01

We show that the derivative of the logarithm of the average characteristic polynomial of a diffusing Wishart matrix obeys an exact partial differential equation valid for an arbitrary value of N, the size of the matrix. In the large N limit, this equation generalizes the simple inviscid Burgers equation that has been obtained earlier for Hermitian or unitary matrices. The solution, through the method of characteristics, presents singularities that we relate to the precursors of shock formation in the Burgers equation. The finite N effects appear as a viscosity term in the Burgers equation. Using a scaling analysis of the complete equation for the characteristic polynomial, in the vicinity of the shocks, we recover in a simple way the universal Bessel oscillations (so-called hard-edge singularities) familiar in random-matrix theory.

Formic acid dimers in a nitrogen matrix

Science.gov (United States)

Lopes, Susy; Fausto, Rui; Khriachtchev, Leonid

2018-01-01

Formic acid (HCOOH) dimers are studied by infrared spectroscopy in a nitrogen matrix and by ab initio calculations. We benefit from the use of a nitrogen matrix where the lifetime of the higher-energy (cis) conformer is very long (˜11 h vs. 7 min in an argon matrix). As a result, in a nitrogen matrix, a large proportion of the cis conformer can be produced by vibrational excitation of the lower-energy (trans) conformer. Three trans-trans, four trans-cis, and three cis-cis dimers are found in the experiments. The spectroscopic information on most of these dimers is enriched compared to the previous studies in an argon matrix. The cis-cis dimers of ordinary formic acid (without deuteration) are reported here for the first time. Several conformational processes are obtained using selective excitation by infrared light, some of them also for the first time. In particular, we report on the formation of cis-cis dimers upon vibrational excitation of trans-cis dimers. Tunneling decays of several dimers have been detected in the dark. The tunneling decay of cis-cis dimers of formic acid as well as the stabilization of cis units in cis-cis dimers is also observed for the first time.

Erythorbic acid promoted formation of CdS QDs in a tube-in-tube micro-channel reactor

Energy Technology Data Exchange (ETDEWEB)

Liang, Yan; Tan, Jiawei; Wang, Jiexin; Chen, Jianfeng [State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Sun, Baochang, E-mail: sunbc@mail.buct.edu.cn [State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Shao, Lei, E-mail: shaol@mail.buct.edu.cn [State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)

2014-12-15

Erythorbic acid assistant synthesis of CdS quantum dots (QDs) was conducted by homogeneous mixing of two continuous liquids in a high-throughput microporous tube-in-tube micro-channel reactor (MTMCR) at room temperature. The effects of the micropore size of the MTMCR, liquid flow rate, mixing time and reactant concentration on the size and size distribution of CdS QDs were investigated. It was found that the size and size distribution of CdS QDs could be tuned in the MTMCR. A combination of erythorbic acid promoted formation technique with the MTMCR may be a promising pathway for controllable mass production of QDs.

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander; Genton, Marc G.; Sun, Ying

2015-01-01

We approximate large non-structured Matérn covariance matrices of size n×n in the H-matrix format with a log-linear computational cost and storage O(kn log n), where rank k ≪ n is a small integer. Applications are: spatial statistics, machine learning and image analysis, kriging and optimal design.

Hierarchical matrix approximation of large covariance matrices

KAUST Repository

Litvinenko, Alexander

2015-11-30

We approximate large non-structured Matérn covariance matrices of size n×n in the H-matrix format with a log-linear computational cost and storage O(kn log n), where rank k ≪ n is a small integer. Applications are: spatial statistics, machine learning and image analysis, kriging and optimal design.

Exploiting Data Sparsity for Large-Scale Matrix Computations

KAUST Repository

Akbudak, Kadir

2018-02-24

Exploiting data sparsity in dense matrices is an algorithmic bridge between architectures that are increasingly memory-austere on a per-core basis and extreme-scale applications. The Hierarchical matrix Computations on Manycore Architectures (HiCMA) library tackles this challenging problem by achieving significant reductions in time to solution and memory footprint, while preserving a specified accuracy requirement of the application. HiCMA provides a high-performance implementation on distributed-memory systems of one of the most widely used matrix factorization in large-scale scientific applications, i.e., the Cholesky factorization. It employs the tile low-rank data format to compress the dense data-sparse off-diagonal tiles of the matrix. It then decomposes the matrix computations into interdependent tasks and relies on the dynamic runtime system StarPU for asynchronous out-of-order scheduling, while allowing high user-productivity. Performance comparisons and memory footprint on matrix dimensions up to eleven million show a performance gain and memory saving of more than an order of magnitude for both metrics on thousands of cores, against state-of-the-art open-source and vendor optimized numerical libraries. This represents an important milestone in enabling large-scale matrix computations toward solving big data problems in geospatial statistics for climate/weather forecasting applications.

Exploiting Data Sparsity for Large-Scale Matrix Computations

KAUST Repository

Akbudak, Kadir; Ltaief, Hatem; Mikhalev, Aleksandr; Charara, Ali; Keyes, David E.

2018-01-01

Exploiting data sparsity in dense matrices is an algorithmic bridge between architectures that are increasingly memory-austere on a per-core basis and extreme-scale applications. The Hierarchical matrix Computations on Manycore Architectures (HiCMA) library tackles this challenging problem by achieving significant reductions in time to solution and memory footprint, while preserving a specified accuracy requirement of the application. HiCMA provides a high-performance implementation on distributed-memory systems of one of the most widely used matrix factorization in large-scale scientific applications, i.e., the Cholesky factorization. It employs the tile low-rank data format to compress the dense data-sparse off-diagonal tiles of the matrix. It then decomposes the matrix computations into interdependent tasks and relies on the dynamic runtime system StarPU for asynchronous out-of-order scheduling, while allowing high user-productivity. Performance comparisons and memory footprint on matrix dimensions up to eleven million show a performance gain and memory saving of more than an order of magnitude for both metrics on thousands of cores, against state-of-the-art open-source and vendor optimized numerical libraries. This represents an important milestone in enabling large-scale matrix computations toward solving big data problems in geospatial statistics for climate/weather forecasting applications.

Promoter And Duties And Responsibilities Of Promoters In English Company Law

OpenAIRE

Neval Okan

2003-01-01

Any person who does an act with reference to the formation of a company or in aid of its organization whether he has the intention to be a partners or not is a promoter. No statuory definition of promoter is given in English company law; definition is given in case law. Promoters stand in a fiduciary relation to the proposed company. Apromoter is not an agent for the company which he is forming because a company cannot have an agent before it comes into existence. The fiduciary duty is owed t...

Kaempferol-immobilized titanium dioxide promotes formation of new bone: effects of loading methods on bone marrow stromal cell differentiation in vivo and in vitro.

Science.gov (United States)

Tsuchiya, Shuhei; Sugimoto, Keisuke; Kamio, Hisanobu; Okabe, Kazuto; Kuroda, Kensuke; Okido, Masazumi; Hibi, Hideharu

2018-01-01

Surface modification of titanium dioxide (TiO 2 ) implants promotes bone formation and shortens the osseointegration period. Kaempferol is a flavonoid that has the capacity to promote osteogenic differentiation in bone marrow stromal cells. The aim of this study was to promote bone formation around kaempferol immobilized on TiO 2 implants. There were four experimental groups. Alkali-treated TiO 2 samples (implants and discs) were used as a control and immersed in Dulbecco's phosphate-buffered saline (DPBS) (Al-Ti). For the coprecipitation sample (Al-cK), the control samples were immersed in DPBS containing 50 µg kaempferol/100% ethanol. For the adsorption sample (Al-aK), 50 µg kaempferol/100% ethanol was dropped onto control samples. The surface topography of the TiO 2 implants was observed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, and a release assay was performed. For in vitro experiments, rat bone marrow stromal cells (rBMSCs) were cultured on each of the TiO 2 samples to analyze cell proliferation, alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. For in vivo experiments, TiO 2 implants placed on rat femur bones were analyzed for bone-implant contact by histological methods. Kaempferol was detected on the surface of Al-cK and Al-aK. The results of the in vitro study showed that rBMSCs cultured on Al-cK and Al-aK promoted alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. The in vivo histological analysis revealed that Al-cK and Al-aK stimulated new bone formation around implants. TiO 2 implant-immobilized kaempferol may be an effective tool for bone regeneration around dental implants.

Structure and decomposition of the silver formate Ag(HCO{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Puzan, Anna N., E-mail: anna_puzan@mail.ru; Baumer, Vyacheslav N.; Mateychenko, Pavel V.

2017-02-15

Crystal structure of the silver formate Ag(HCO{sub 2}) has been determined (orthorhombic, sp.gr. Pccn, a=7.1199(5), b=10.3737(4), c=6.4701(3)Å, V=477.88(4) Å{sup 3}, Z=8). The structure contains isolated formate ions and the pairs Ag{sub 2}{sup 2+} which form the layers in (001) planes (the shortest Ag–Ag distances is 2.919 in the pair and 3.421 and 3.716 Å between the nearest Ag atoms of adjacent pairs). Silver formate is unstable compound which decompose spontaneously vs time. Decomposition was studied using Rietveld analysis of the powder diffraction patterns. It was concluded that the diffusion of Ag atoms leads to the formation of plate-like metal particles as nuclei in the (100) planes which settle parallel to (001) planes of the silver formate matrix. - Highlights: • Silver formate Ag(HCO{sub 2}) was synthesized and characterized. • Layered packing of Ag-Ag pairs in the structure was found. • Decomposition of Ag(HCO{sub 2}) and formation of metal phase were studied. • Rietveld-refined micro-structural characteristics during decomposition reveal the space relationship between the matrix structure and forming Ag phase REPLACE with: Space relationship between the matrix structure and forming Ag phase.

CD14{sup +} monocytes promote the immunosuppressive effect of human umbilical cord matrix stem cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Ding, E-mail: qqhewd@gmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Chen, Ke, E-mail: chenke_59@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Du, Wei Ting, E-mail: duwtpumc@yahoo.com.cn [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); Han, Zhi-Bo, E-mail: zhibohan@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Ren, He, E-mail: knifesharp2000@hotmail.com [National Engineering Research Center of Cell Products, AmCellGene Co. Ltd, TEDA, Tianjin (China); Chi, Ying, E-mail: caizhuying@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); and others

2010-09-10

Here, the effect of CD14{sup +} monocytes on human umbilical cord matrix stem cell (hUC-MSC)-mediated immunosuppression was studied in vitro. hUC-MSCs exerted a potent inhibitory effect on the proliferation and interferon-{gamma} (IFN-{gamma}) secretion capacities of CD4{sup +} and CD8{sup +} T cells in response to anti-CD3/CD28 stimulation. Transwell co-culture system revealed that the suppressive effect was primarily mediated by soluble factors. Addition of prostaglandin synthesis inhibitors (indomethacin or NS-398) almost completely abrogated the immunosuppression activity of hUC-MSCs, identifying prostaglandin E{sub 2} (PGE{sub 2}) as an important soluble mediator. CD14{sup +} monocytes were found to be able to enhance significantly the immunosuppressive effect of hUC-MSCs in a dose-dependent fashion. Moreover, the inflammatory cytokine IL-1{beta}, either exogenously added or produced by CD14{sup +} monocytes in culture, could trigger expression of high levels of PGE{sub 2} by hUC-MSCs, whereas inclusion of the IL-1 receptor antagonist (IL-1RA) in the culture down-regulated not only PGE{sub 2} expression, but also reversed the promotional effect of CD14{sup +} monocytes and partially restored CD4{sup +} and CD8{sup +} T cell proliferation and IFN-{gamma} secretion. Our data demonstrate an important role of monocytes in the hUC-MSC-induced immunomodulation, which may have important implications in future efforts to explore the clinical potentials of hUC-MSCs.

A significant abiotic pathway for the formation of unknown nitrogen in nature

Science.gov (United States)

Jokic, A.; Schulten, H.-R.; Cutler, J. N.; Schnitzer, M.; Huang, P. M.

2004-03-01

The global nitrogen cycle is of prime importance in natural ecosystems. However, the origin and nature of up to one-half of total soil N remains obscure despite all attempts at elucidation. Our data provide, for the first time, unequivocal evidence that the promoting action of Mn (IV) oxide on the Maillard reaction (sugar-amino acid condensation) under ambient conditions results in the abiotic formation of heterocyclic N compounds, which are often referred to as unknown nitrogen, and of amides which are apparently the dominant N moieties in nature. The information presented is of fundamental significance in understanding the role of mineral colloids in abiotic transformations of organic N moieties, the incorporation of N in the organic matrix of fossil fuels, and the global N cycle.

Processing of aluminum matrix composites by electroless plating and melt infiltration

International Nuclear Information System (INIS)

Leon, C.A.; Bourassa, A.-M.; Drew, R.A.L.

2000-01-01

Reduction of the SiC/ Al interaction and enhancement of wetting between reinforcements and molten aluminum was obtained by modifying the ceramic surface with deposition of nickel and copper coatings. The preparation of nickel- and copper-coated ceramic particles as precursors for MMC fabrication was studied. Al 2 O 3 and SiC powders were successfully coated with Ni and Cu using electroless metal plating. Uniform and continuous metal films were deposited on both, alumina and silicon carbide powders XRD showed that the Ni-P deposit was predominantly amorphous, while the copper deposit was essentially polycrystalline. Infiltration results showed that the use of the coated powders enhances the wettability between the matrix and ceramic phase when processing particulate MMCs by a vacuum infiltration technique, giving a porosity-free composite with a homogeneously distributed reinforcing phase. The coating promoted easy metal flow through the preform, compared to the non-infiltration behavior of the uncoated counterpart samples XRD microstructural analysis of the composites indicates the formation of intermetallic phases such as CuAl 2 , in the case of copper coating, and NiAl and NiAl 3 when nickel-coated powders are infiltrated. Metallization of the ceramics minimizes the interfacial reaction of the SiC/Al composites and promotes wetting of Al 2 O 3 reinforcements with liquid aluminum. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

Characteristics of Methane Hydrate Formation in Artificial and Natural Media

Directory of Open Access Journals (Sweden)

Qingbai Wu

2013-03-01

Full Text Available The formation of methane hydrate in two significantly different media was investigated, using silica gel as an artificial medium and loess as a natural medium. The methane hydrate formation was observed through the depletion of water in the matrix, measured via the matrix potential and the relationship between the matrix potential and the water content was determined using established equations. The velocity of methane hydrate nucleation slowed over the course of the reaction, as it relied on water transfer to the hydrate surfaces with lower Gibbs free energy after nucleation. Significant differences in the reactions in the two types of media arose from differences in the water retention capacity and lithology of media due to the internal surface area and pore size distributions. Compared with methane hydrate formation in silica gel, the reaction in loess was much slower and formed far less methane hydrate. The results of this study will advance the understanding of how the properties of the environment affect the formation of gas hydrates in nature.

Two genetic loci produce distinct carbohydrate-rich structural components of the Pseudomonas aeruginosa biofilm matrix.

Science.gov (United States)

Friedman, Lisa; Kolter, Roberto

2004-07-01

Pseudomonas aeruginosa forms biofilms, which are cellular aggregates encased in an extracellular matrix. Molecular genetics studies of three common autoaggregative phenotypes, namely wrinkled colonies, pellicles, and solid-surface-associated biofilms, led to the identification of two loci, pel and psl, that are involved in the production of carbohydrate-rich components of the biofilm matrix. The pel gene cluster is involved in the production of a glucose-rich matrix material in P. aeruginosa strain PA14 (L. Friedman and R. Kolter, Mol. Microbiol. 51:675-690, 2004). Here we investigate the role of the pel gene cluster in P. aeruginosa strain ZK2870 and identify a second genetic locus, termed psl, involved in the production of a mannose-rich matrix material. The 11 predicted protein products of the psl genes are homologous to proteins involved in carbohydrate processing. P. aeruginosa is thus able to produce two distinct carbohydrate-rich matrix materials. Either carbohydrate-rich matrix component appears to be sufficient for mature biofilm formation, and at least one of them is required for mature biofilm formation in P. aeruginosa strains PA14 and ZK2870. Copyright 2004 American Society for Microbiology

NONLINEAR PLANT PIECEWISE-CONTINUOUS MODEL MATRIX PARAMETERS ESTIMATION

Directory of Open Access Journals (Sweden)

Roman L. Leibov

2017-09-01

Full Text Available This paper presents a nonlinear plant piecewise-continuous model matrix parameters estimation technique using nonlinear model time responses and random search method. One of piecewise-continuous model application areas is defined. The results of proposed approach application for aircraft turbofan engine piecewisecontinuous model formation are presented

Formative assessment promotes learning in undergraduate clinical ...

African Journals Online (AJOL)

Introduction. Clinical clerkships, typically situated in environments lacking educational structure, form the backbone of undergraduate medical training. The imperative to develop strategies that enhance learning in this context is apparent. This study explored the impact of longitudinal bedside formative assessment on ...

Matrix remodeling between cells and cellular interactions with collagen bundle

Science.gov (United States)

Kim, Jihan; Sun, Bo

When cells are surrounded by complex environment, they continuously probe and interact with it by applying cellular traction forces. As cells apply traction forces, they can sense rigidity of their local environment and remodel the matrix microstructure simultaneously. Previous study shows that single human carcinoma cell (MDA-MB-231) remodeled its surrounding extracellular matrix (ECM) and the matrix remodeling was reversible. In this study we examined the matrix microstructure between cells and cellular interaction between them using quantitative confocal microscopy. The result shows that the matrix microstructure is the most significantly remodeled between cells consisting of aligned, and densified collagen fibers (collagen bundle)., the result shows that collagen bundle is irreversible and significantly change micromechanics of ECM around the bundle. We further examined cellular interaction with collagen bundle by analyzing dynamics of actin and talin formation along with the direction of bundle. Lastly, we analyzed dynamics of cellular protrusion and migrating direction of cells along the bundle.

Mechanosensing in cell–matrix adhesions – Converting tension into chemical signals

International Nuclear Information System (INIS)

Hytönen, Vesa P.; Wehrle-Haller, Bernhard

2016-01-01

Cell-matrix adhesions have since long been recognized to be critical for the survival and proliferation of cells. In fact, these adhesive structures do not only physically anchor cells, but they also induce vital intracellular signaling at cell-matrix adhesion sites. Recent progress in the cell adhesion field is now starting to provide data and ideas how this so far enigmatic signaling process is induced and regulated by intracellular acto-myosin tension, or stiffness of the extracellular matrix. Understanding how cells are using this mechanosignaling system will be key to control biological processes such as development, cancer growth, metastasis formation and tissue regeneration. In this review, we illustrate and discuss the mechanosignaling mechanisms important in the regulation of cell-matrix adhesions at the molecular level.

Mechanosensing in cell–matrix adhesions – Converting tension into chemical signals

Energy Technology Data Exchange (ETDEWEB)

Hytönen, Vesa P. [BioMediTech, University of Tampere, Biokatu 6, FI-33520 Tampere (Finland); Fimlab Laboratories, Biokatu 4, FI-33520 Tampere (Finland); Wehrle-Haller, Bernhard [University of Geneva, Department of Cell Physiology and Metabolism, Centre Médical Universitaire, 1. Rue Michel-Servet, 1211 Geneva 4 (Switzerland); University of Geneva, Diabetes Center, Medical Faculty, 1211 Geneva 4 (Switzerland)

2016-04-10

Cell-matrix adhesions have since long been recognized to be critical for the survival and proliferation of cells. In fact, these adhesive structures do not only physically anchor cells, but they also induce vital intracellular signaling at cell-matrix adhesion sites. Recent progress in the cell adhesion field is now starting to provide data and ideas how this so far enigmatic signaling process is induced and regulated by intracellular acto-myosin tension, or stiffness of the extracellular matrix. Understanding how cells are using this mechanosignaling system will be key to control biological processes such as development, cancer growth, metastasis formation and tissue regeneration. In this review, we illustrate and discuss the mechanosignaling mechanisms important in the regulation of cell-matrix adhesions at the molecular level.

Matrix completion by deep matrix factorization.

Science.gov (United States)

Fan, Jicong; Cheng, Jieyu

2018-02-01

Conventional methods of matrix completion are linear methods that are not effective in handling data of nonlinear structures. Recently a few researchers attempted to incorporate nonlinear techniques into matrix completion but there still exists considerable limitations. In this paper, a novel method called deep matrix factorization (DMF) is proposed for nonlinear matrix completion. Different from conventional matrix completion methods that are based on linear latent variable models, DMF is on the basis of a nonlinear latent variable model. DMF is formulated as a deep-structure neural network, in which the inputs are the low-dimensional unknown latent variables and the outputs are the partially observed variables. In DMF, the inputs and the parameters of the multilayer neural network are simultaneously optimized to minimize the reconstruction errors for the observed entries. Then the missing entries can be readily recovered by propagating the latent variables to the output layer. DMF is compared with state-of-the-art methods of linear and nonlinear matrix completion in the tasks of toy matrix completion, image inpainting and collaborative filtering. The experimental results verify that DMF is able to provide higher matrix completion accuracy than existing methods do and DMF is applicable to large matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

A genetic meta-algorithm-assisted inversion approach: hydrogeological study for the determination of volumetric rock properties and matrix and fluid parameters in unsaturated formations

Science.gov (United States)

Szabó, Norbert Péter

2018-03-01

An evolutionary inversion approach is suggested for the interpretation of nuclear and resistivity logs measured by direct-push tools in shallow unsaturated sediments. The efficiency of formation evaluation is improved by estimating simultaneously (1) the petrophysical properties that vary rapidly along a drill hole with depth and (2) the zone parameters that can be treated as constant, in one inversion procedure. In the workflow, the fractional volumes of water, air, matrix and clay are estimated in adjacent depths by linearized inversion, whereas the clay and matrix properties are updated using a float-encoded genetic meta-algorithm. The proposed inversion method provides an objective estimate of the zone parameters that appear in the tool response equations applied to solve the forward problem, which can significantly increase the reliability of the petrophysical model as opposed to setting these parameters arbitrarily. The global optimization meta-algorithm not only assures the best fit between the measured and calculated data but also gives a reliable solution, practically independent of the initial model, as laboratory data are unnecessary in the inversion procedure. The feasibility test uses engineering geophysical sounding logs observed in an unsaturated loessy-sandy formation in Hungary. The multi-borehole extension of the inversion technique is developed to determine the petrophysical properties and their estimation errors along a profile of drill holes. The genetic meta-algorithmic inversion method is recommended for hydrogeophysical logging applications of various kinds to automatically extract the volumetric ratios of rock and fluid constituents as well as the most important zone parameters in a reliable inversion procedure.

Control of cell fate by the formation of an architecturally complex bacterial community.

Science.gov (United States)

Vlamakis, Hera; Aguilar, Claudio; Losick, Richard; Kolter, Roberto

2008-04-01

Bacteria form architecturally complex communities known as biofilms in which cells are held together by an extracellular matrix. Biofilms harbor multiple cell types, and it has been proposed that within biofilms individual cells follow different developmental pathways, resulting in heterogeneous populations. Here we demonstrate cellular differentiation within biofilms of the spore-forming bacterium Bacillus subtilis, and present evidence that formation of the biofilm governs differentiation. We show that motile, matrix-producing, and sporulating cells localize to distinct regions within the biofilm, and that the localization and percentage of each cell type is dynamic throughout development of the community. Importantly, mutants that do not produce extracellular matrix form unstructured biofilms that are deficient in sporulation. We propose that sporulation is a culminating feature of biofilm formation, and that spore formation is coupled to the formation of an architecturally complex community of cells.

Local System Matrix Compression for Efficient Reconstruction in Magnetic Particle Imaging

Directory of Open Access Journals (Sweden)

T. Knopp

2015-01-01

Full Text Available Magnetic particle imaging (MPI is a quantitative method for determining the spatial distribution of magnetic nanoparticles, which can be used as tracers for cardiovascular imaging. For reconstructing a spatial map of the particle distribution, the system matrix describing the magnetic particle imaging equation has to be known. Due to the complex dynamic behavior of the magnetic particles, the system matrix is commonly measured in a calibration procedure. In order to speed up the reconstruction process, recently, a matrix compression technique has been proposed that makes use of a basis transformation in order to compress the MPI system matrix. By thresholding the resulting matrix and storing the remaining entries in compressed row storage format, only a fraction of the data has to be processed when reconstructing the particle distribution. In the present work, it is shown that the image quality of the algorithm can be considerably improved by using a local threshold for each matrix row instead of a global threshold for the entire system matrix.

Clonorchis sinensis infestation promotes three-dimensional aggregation and invasion of cholangiocarcinoma cells.

Directory of Open Access Journals (Sweden)

Jihee Won

Full Text Available Numerous experimental and epidemiological studies have demonstrated a correlation between Clonorchis sinensis (C. sinensis infestation and cholangiocarcinoma (CCA. However, the role of C. sinensis in the increased invasiveness and proliferation involved in the malignancy of CCA has not been addressed yet. Here, we investigated the possibility that C. sinensis infestation promotes expression of focal and cell-cell adhesion proteins in CCA cells and secretion of matrix metalloproteinases (MMPs. Adhesion proteins help maintain cell aggregates, and MMPs promote the three-dimensional invasion of cells into the neighboring extracellular matrix (ECM. Using a novel microfluidic assay, we quantitatively addressed the role of excretory-secretory products (ESPs gradients from C. sinensis in promoting the invasion of cells into the neighboring ECM.

Okara promoted acrylamide and carboxymethyl-lysine formation in bakery products.

Science.gov (United States)

Palermo, Mariantonella; Fiore, Alberto; Fogliano, Vincenzo

2012-10-10

Soybeans are widely used in bakery products because of their technological advantages and, recently, soybean-containing products have been marketed as functional foods thanks to several health benefits. Okara is a soybean-based ingredient obtained after elimination of the water-soluble component from ground soybeans. In this paper the effect of okara addition to bakery products on the formation of some potentially harmful Maillard reaction products was evaluated. Cookies obtained by replacing 15% of wheat flour with okara showed a visible browning increase and a more intense Maillard reaction development as shown by higher concentrations of 5-hydroxymethyl-2-furaldehyde (HMF) (+100%), acrylamide (+60%), and carboxymethyl-lysine (CML) (+400%) with respect to the control. This phenomenon could be related to the presence in okara of about 50% of insoluble dietary fiber: the fiber reduces water activity during cooking, thus promoting Maillard reaction. To confirm this hypothesis, cookies obtained by replacing 7% of wheat flour with three different types of dietary fiber (cellulose, chitosan, and pea fiber) were prepared: these experimental cookies showed higher Maillard reaction product concentration with respect to the control and, in particular, HMF and CML values were directly related to the fiber water-holding capacity (WHC). To extend the observation to the food market, a sampling of soybean-containing commercial bakery products was analyzed by comparing the concentrations of Maillard reaction products with those of similar bakery products without soy. Soybean-containing samples showed higher concentrations of acrylamide and CML than corresponding controls.

Crystal structure representations for machine learning models of formation energies

Energy Technology Data Exchange (ETDEWEB)

Faber, Felix [Department of Chemistry, Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials, University of Basel Switzerland; Lindmaa, Alexander [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping Sweden; von Lilienfeld, O. Anatole [Department of Chemistry, Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials, University of Basel Switzerland; Argonne Leadership Computing Facility, Argonne National Laboratory, 9700 S. Cass Avenue Lemont Illinois 60439; Armiento, Rickard [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping Sweden

2015-04-20

We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit cell repeated over the lattice; (ii) an extended Coulomb-like matrix that takes into account a number of neighboring unit cells; and (iii) an ansatz that mimics the periodicity and the basic features of the elements in the Ewald sum matrix using a sine function of the crystal coordinates of the atoms. The representations are compared for a Laplacian kernel with Manhattan norm, trained to reproduce formation energies using a dataset of 3938 crystal structures obtained from the Materials Project. For training sets consisting of 3000 crystals, the generalization error in predicting formation energies of new structures corresponds to (i) 0.49, (ii) 0.64, and (iii) 0.37eV/atom for the respective representations.

Optimizing Sparse Matrix-Multiple Vectors Multiplication for Nuclear Configuration Interaction Calculations

Energy Technology Data Exchange (ETDEWEB)

Aktulga, Hasan Metin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Buluc, Aydin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Williams, Samuel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Chao [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2014-08-14

Obtaining highly accurate predictions on the properties of light atomic nuclei using the configuration interaction (CI) approach requires computing a few extremal Eigen pairs of the many-body nuclear Hamiltonian matrix. In the Many-body Fermion Dynamics for nuclei (MFDn) code, a block Eigen solver is used for this purpose. Due to the large size of the sparse matrices involved, a significant fraction of the time spent on the Eigen value computations is associated with the multiplication of a sparse matrix (and the transpose of that matrix) with multiple vectors (SpMM and SpMM-T). Existing implementations of SpMM and SpMM-T significantly underperform expectations. Thus, in this paper, we present and analyze optimized implementations of SpMM and SpMM-T. We base our implementation on the compressed sparse blocks (CSB) matrix format and target systems with multi-core architectures. We develop a performance model that allows us to understand and estimate the performance characteristics of our SpMM kernel implementations, and demonstrate the efficiency of our implementation on a series of real-world matrices extracted from MFDn. In particular, we obtain 3-4 speedup on the requisite operations over good implementations based on the commonly used compressed sparse row (CSR) matrix format. The improvements in the SpMM kernel suggest we may attain roughly a 40% speed up in the overall execution time of the block Eigen solver used in MFDn.

Heterotopic bone formation in the musculus latissimus dorsi of sheep using β-tricalcium phosphate scaffolds: evaluation of an extended prefabrication time on bone formation and matrix degeneration.

Science.gov (United States)

Spalthoff, S; Jehn, P; Zimmerer, R; Möllmann, U; Gellrich, N-C; Kokemueller, H

2015-06-01

We previously generated viable heterotopic bone in living animals and found that 3 months of intrinsic vascularization improved bone formation and matrix degeneration. In this study, we varied the pre-vascularization time to determine its effects on the kinetics of bone formation and ceramic degradation. Two 25-mm-long cylindrical β-tricalcium phosphate scaffolds were filled intraoperatively with autogenous iliac crest bone marrow and implanted in the latissimus dorsi muscle in six sheep. To examine the effect of axial perfusion, one scaffold was surgically implanted with (group C) or without (group D) a central vascular bundle. All animals were sacrificed 6 months postoperatively and histomorphometric measurements were compared to previous results. All implanted scaffolds exhibited ectopic bone growth. However, bone growth was not significantly different between the 3-month (group A, 0.191±0.097 vs. group C, 0.237±0.075; P=0.345) and 6-month (group B, 0.303±0.105 vs. group D, 0.365±0.258; P=0.549) pre-vascularization durations, regardless of vessel supply; early differences between surgically and extrinsically vascularized constructs disappeared after 6 months. Here, we describe a reliable procedure for generating ectopic bone in vivo. A 3-month pre-vascularization duration appears sufficient and ceramic degradation proceeds in accordance with bone generation, supporting the hypothesis of cell-mediated resorption. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Age-related collagen turnover of the interstitial matrix and basement membrane: Implications of age- and sex-dependent remodeling of the extracellular matrix

DEFF Research Database (Denmark)

Kehlet, Stephanie N.; Willumsen, Nicholas; Armbrecht, Gabriele

2018-01-01

The extracellular matrix (ECM) plays a vital role in maintaining normal tissue function. Collagens are major components of the ECM and there is a tight equilibrium between degradation and formation of these proteins ensuring tissue health and homeostasis. As a consequence of tissue turnover, small...... collagen fragments are released into the circulation, which act as important biomarkers in the study of certain tissue-related remodeling factors in health and disease. The aim of this study was to establish an age-related collagen turnover profile of the main collagens of the interstitial matrix (type I...... an increased turnover. In summary, collagen turnover is affected by age and sex with the interstitial matrix and the basement membrane being differently regulated. The observed changes needs to be accounted for when measuring ECM related biomarkers in clinical studies....

Model for UV induced formation of gold nanoparticles in solid polymeric matrices

Science.gov (United States)

Sapogova, N.; Bityurin, N.

2009-09-01

UV irradiation of polymeric PMMA films containing HAuCl 4 followed by annealing at 60-80 °C forms gold nanoparticles directly within the bulk material. The kinetics of nanoparticle formation was traced by extinction spectra of nanocomposite film changes vs annealing time. We propose that UV irradiation causes HAuCl 4 dissociation and thus provides a polymeric matrix with atomic gold. The presence of an oversaturated solid solution of atomic gold in the polymeric matrix leads to Au nanoparticle formation during annealing. This process can be understood as a phase transition of the first order. In this paper we apply several common kinetic models of the phase transition for describing Au nanoparticle formation inside the solid polymer matrix. We compare predictions of these models with the experimental data and show that these models cannot describe the process. We propose that the stabilization effect of the matrix on the growing gold nanoparticles is important. The simplest model introducing some probability for the transition from growing nanoparticle to the non-growing, stabilized form is suggested. It is shown that this model satisfactorily describes the experimentally observed evolution of the extinction spectrum of Au nanoparticles forming in a polymer matrix.

The Use of Injectable Chitosan/Nanohydroxyapatite/Collagen Composites with Bone Marrow Mesenchymal Stem Cells to Promote Ectopic Bone Formation In Vivo

Directory of Open Access Journals (Sweden)

Bo Yu

2013-01-01

Full Text Available The aim of this study was to evaluate ectopic in vivo bone formation with or without rat bone mesenchymal stem cells (rBMSCs of an injectable Chitosan/Nanohydroxyapatite/Collagen (CS/nHAC composite. The CS/nHAC composites were injected subcutaneously into the backs of Wistar rats with freshly loaded rBMSCs at a density of 10×106 cells/mL, and the CS/nHAC composites without cells were used as negative controls. New bone formation, degradation of composites, and degree of calcification were evaluated by Computed Tomography (CT and three-dimensional (3D CT reconstruction. Histological evaluations were performed to further assess bone structure and extracellular matrix by HE and Masson staining. The inflammatory reactions related to osteogenesis were also investigated in the present study. In comparison with the CS/nHAC composites, this study revealed that CS/nHAC/rBMSCs composites showed relatively higher percentage of calcification, better establishment of ECM, and less degradation rate. Meanwhile, different extents of inflammatory reactions were also observed in the CS/nHAC and CS/nHAC/rBMSCs explants at 2 and 4 weeks after implantation. Altogether, CS/nHAC/rBMSCs composites are superior to CS/nHAC composites in ectopic bone formation. In conclusion, the rBMSCs-seeded CS/nHAC composites may be beneficial to enhancing ectopic bone formation in vivo.

Effects of matrix elasticity and cell density on human mesenchymal stem cells differentiation.

Science.gov (United States)

Xue, Ruyue; Li, Julie Yi-Shuan; Yeh, Yiting; Yang, Li; Chien, Shu

2013-09-01

Human mesenchymal stem cells (hMSCs) can differentiate into various cell types, including osteogenic and chondrogenic cells. The matrix elasticity and cell seeding density are important factors in hMSCs differentiation. We cultured hMSCs at different seeding densities on polyacrylamide hydrogels with different stiffness corresponding to Young's moduli of 1.6 ± 0.3 and 40 ± 3.6 kPa. The promotion of osteogenic marker expression by hard gel is overridden by a high seeding density. Cell seeding density, however, did not influence the chondrogenic marker expressions induced by soft gel. These findings suggest that interplays between cell-matrix and cell-cell interactions contribute to hMSCs differentiation. The promotion of osteogenic differentiation on hard matrix was shown to be mediated through the Ras pathway. Inhibition of Ras (RasN17) significantly decreased ERK, Smad1/5/8 and AKT activation, and osteogenic markers expression. However, constitutively active Ras (RasV12) had little effect on osteogenic marker expression, suggesting that the Ras pathways are necessary but not sufficient for osteogenesis. Taken together, our results indicate that matrix elasticity and cell density are important microenvironmental cues driving hMSCs proliferation and differentiation. Copyright © 2013 Orthopaedic Research Society.

MoS_2/Ag nanohybrid: A novel matrix with synergistic effect for small molecule drugs analysis by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Zhao, Yaju; Deng, Guoqing; Liu, Xiaohui; Sun, Liang; Li, Hui; Cheng, Quan; Xi, Kai; Xu, Danke

2016-01-01

This paper reports a facile synthesis of molybdenum disulfide nanosheets/silver nanoparticles (MoS_2/Ag) hybrid and its use as an effective matrix in negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The nanohybrid exerts a strong synergistic effect, leading to high performance detection of small molecule analytes including amino acids, peptides, fatty acids and drugs. The enhancement of laser desorption/ionization (LDI) efficiency is largely attributed to the high surface roughness and large surface area for analyte adsorption, better dispersibility, increased thermal conductivity and enhanced UV energy absorption as compared to pure MoS_2. Moreover, both Ag nanoparticles and the edge of the MoS_2 layers function as deprotonation sites for proton capture, facilitating the charging process in negative ion mode and promoting formation of negative ions. As a result, the MoS_2/Ag nanohybrid proves to be a highly attractive matrix in MALDI-TOF MS, with desired features such as high desorption/ionization efficiency, low fragmentation interference, high salt tolerance, and no sweet-spots for mass signal. These characteristic properties allowed for simultaneous analysis of eight different drugs and quantification of acetylsalicylic acid in the spiked human serum. This work demonstrates for the first time the fabrication and application of a novel MoS_2/Ag hybrid, and provides a new platform for use in the rapid and high throughput analysis of small molecules by mass spectrometry. - Highlights: • MoS_2/Ag nanohybrid was applied as a novel matrix in negative-ion MALDI-TOF MS. • The MoS_2/Ag nanohybrid exerted synergistic effect on the detection of small molecules. • The MoS_2/Ag nanohybrid showed good signal reproducibility and low background interferences comparing to organic matrices. • MoS_2/Ag allows simultaneous analysis of multiple drugs and quantification of acetylsalicylic acid in spiked serum samples.

Osteogenic Matrix Cell Sheets Facilitate Osteogenesis in Irradiated Rat Bone

Directory of Open Access Journals (Sweden)

Yoshinobu Uchihara

2015-01-01

Full Text Available Reconstruction of large bone defects after resection of malignant musculoskeletal tumors is a significant challenge in orthopedic surgery. Extracorporeal autogenous irradiated bone grafting is a treatment option for bone reconstruction. However, nonunion often occurs because the osteogenic capacity is lost by irradiation. In the present study, we established an autogenous irradiated bone graft model in the rat femur to assess whether osteogenic matrix cell sheets improve osteogenesis of the irradiated bone. Osteogenic matrix cell sheets were prepared from bone marrow-derived stromal cells and co-transplanted with irradiated bone. X-ray images at 4 weeks after transplantation showed bridging callus formation around the irradiated bone. Micro-computed tomography images at 12 weeks postoperatively showed abundant callus formation in the whole circumference of the irradiated bone. Histology showed bone union between the irradiated bone and host femur. Mechanical testing showed that the failure force at the irradiated bone site was significantly higher than in the control group. Our study indicates that osteogenic matrix cell sheet transplantation might be a powerful method to facilitate osteogenesis in irradiated bones, which may become a treatment option for reconstruction of bone defects after resection of malignant musculoskeletal tumors.

Convergence of bone morphogenetic protein and laminin-1 signaling pathways promotes proliferation and colony formation by fetal mouse pancreatic cells

International Nuclear Information System (INIS)

Jiang Fangxu; Harrison, Leonard C.

2005-01-01

We previously reported that bone morphogenetic proteins (BMPs), members of the transforming growth factor superfamily, together with the basement membrane glycoprotein laminin-1 (Ln-1), promote proliferation of fetal pancreatic cells and formation of colonies containing peripheral insulin-positive cells. Here, we further investigate the cross-talk between BMP and Ln-1 signals. By RT-PCR, receptors for BMP (BMPR) (excepting BMPR-1B) and Ln-1 were expressed in the fetal pancreas between E13.5 and E17.5. Specific blocking antibodies to BMP-4 and -6 and selective BMP antagonists partially inhibited colony formation by fetal pancreas cells. Colony formation induced by BMP-6 and Ln-1 was completely abolished in a dose-dependent manner by blocking Ln-1 binding to its α 6 integrin and α-dystroglycan receptors or by blocking the Ln-1 signaling molecules, phosphatidyl-inositol-3-kinase (P13K) and MAP kinase kinase-1. These results demonstrate a convergence of BMP and Ln-1 signaling through P13K and MAP kinase pathways to induce proliferation and colony formation in E15.5 fetal mouse pancreatic cells

Escherichia coli biofilms have an organized and complex extracellular matrix structure.

Science.gov (United States)

Hung, Chia; Zhou, Yizhou; Pinkner, Jerome S; Dodson, Karen W; Crowley, Jan R; Heuser, John; Chapman, Matthew R; Hadjifrangiskou, Maria; Henderson, Jeffrey P; Hultgren, Scott J

2013-09-10

Bacterial biofilms are ubiquitous in nature, and their resilience is derived in part from a complex extracellular matrix that can be tailored to meet environmental demands. Although common developmental stages leading to biofilm formation have been described, how the extracellular components are organized to allow three-dimensional biofilm development is not well understood. Here we show that uropathogenic Escherichia coli (UPEC) strains produce a biofilm with a highly ordered and complex extracellular matrix (ECM). We used electron microscopy (EM) techniques to image floating biofilms (pellicles) formed by UPEC. EM revealed intricately constructed substructures within the ECM that encase individual, spatially segregated bacteria with a distinctive morphology. Mutational and biochemical analyses of these biofilms confirmed curli as a major matrix component and revealed important roles for cellulose, flagella, and type 1 pili in pellicle integrity and ECM infrastructure. Collectively, the findings of this study elucidated that UPEC pellicles have a highly organized ultrastructure that varies spatially across the multicellular community. Bacteria can form biofilms in diverse niches, including abiotic surfaces, living cells, and at the air-liquid interface of liquid media. Encasing these cellular communities is a self-produced extracellular matrix (ECM) that can be composed of proteins, polysaccharides, and nucleic acids. The ECM protects biofilm bacteria from environmental insults and also makes the dissolution of biofilms very challenging. As a result, formation of biofilms within humans (during infection) or on industrial material (such as water pipes) has detrimental and costly effects. In order to combat bacterial biofilms, a better understanding of components required for biofilm formation and the ECM is required. This study defined the ECM composition and architecture of floating pellicle biofilms formed by Escherichia coli.

The effect of riboflavin/UVA cross-linking on anti-degeneration and promoting angiogenic capability of decellularized liver matrix.

Science.gov (United States)

Xiang, Junxi; Liu, Peng; Zheng, Xinglong; Dong, Dinghui; Fan, Shujuan; Dong, Jian; Zhang, Xufeng; Liu, Xuemin; Wang, Bo; Lv, Yi

2017-10-01

Weak mechanical property and unstable degradation rate limited the application of decellularized liver matrix in tissue engineering. The aim of this study was to explore a new method for improving the mechanical properties, anti-degeneration and angiogenic capability of decellularized liver matrix. This was achieved by a novel approach using riboflavin/ultraviolet A treatment to induce collagen cross-linking of decellularized matrix. Histological staining and scanning electron microscope showed that the diameter of cross-linked fibers significantly increased compared with the control group. The average peak load and Young's modulus of decellularized matrix were obviously improved after cross-linking. Then we implanted the modified matrix into the rat hepatic injury model to test the anti-degeneration and angiogenic capability of riboflavin/UVA cross-linked decellularized liver scaffolds in vivo. The results indicated that cross-linked scaffolds degrade more slowly than those in the control group. In the experiment group, average microvessel density in the implanted matrix was higher than that in the control group since the first week after implantation. In conclusion, we initiated the method to improve the biomechanical properties of decellularized liver scaffolds by riboflavin/UVA cross-linking, and more importantly, its improvement on anti-degeneration and angiogenesis was identified. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2662-2669, 2017. © 2017 Wiley Periodicals, Inc.

Interval and continuous exercise regimens suppress neutrophil-derived microparticle formation and neutrophil-promoted thrombin generation under hypoxic stress.

Science.gov (United States)

Chen, Yi-Ching; Ho, Ching-Wen; Tsai, Hsing-Hua; Wang, Jong-Shyan

2015-04-01

Acute hypoxic exposure increases vascular thrombotic risk. The release of procoagulant-rich microparticles from neutrophils accelerates the pathogenesis of inflammatory thrombosis. The present study explicates the manner in which interval and continuous exercise regimens affect neutrophil-derived microparticle (NDMP) formation and neutrophil/NDMP-mediated thrombin generation (TG) under hypoxic condition. A total of 60 sedentary males were randomized to perform either aerobic interval training [AIT; 3-min intervals at 40% and 80% V̇O2max (maximal O2 consumption)] or moderate continuous training (MCT; sustained 60% V̇O2max) for 30 min/day, 5 days/week for 5 weeks, or to a control (CTL) group who did not receive any form of training. At rest and immediately after hypoxic exercise test (HE, 100 W under 12% O2 for 30 min), the NDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. Before the intervention, HE (i) elevated coagulant factor VIII/fibrinogen concentrations and shortened activated partial thromboplastin time (aPTT), (ii) increased total and tissue factor (TF)-rich/phosphatidylserine (PS)-exposed NDMP counts and (iii) enhanced the peak height and rate of TG promoted by neutrophils/NDMPs. Following the 5-week intervention, AIT exhibited higher enhancement of V̇O2max than did MCT. Notably, both MCT and AIT attenuated the extents of HE-induced coagulant factor VIII/fibrinogen elevations and aPTT shortening. Furthermore, the two exercise regimens significantly decreased TF-rich/PS-exposed NDMP formation and depressed neutrophil/NDMP-mediated dynamic TG at rest and following HE. Hence, we conclude that AIT is superior to MCT for enhancing aerobic capacity. Moreover, either AIT or MCT effectively ameliorates neutrophil/NDMP-promoted TG by down-regulating expression of procoagulant factors during HE, which may reduce thrombotic risk evoked by hypoxia. Moreover, either AIT or MCT effectively ameliorates neutrophil/NDMP-promoted

Matrix metalloproteinase-2 of human carotid atherosclerotic plaques promotes platelet activation. Correlation with ischaemic events.

Science.gov (United States)

Lenti, Massimo; Falcinelli, Emanuela; Pompili, Marcella; de Rango, Paola; Conti, Valentina; Guglielmini, Giuseppe; Momi, Stefania; Corazzi, Teresa; Giordano, Giuseppe; Gresele, Paolo

2014-06-01

Purified active matrix metalloproteinase-2 (MMP-2) is able to promote platelet aggregation. We aimed to assess the role of MMP-2 expressed in atherosclerotic plaques in the platelet-activating potential of human carotid plaques and its correlation with ischaemic events. Carotid plaques from 81 patients undergoing endarterectomy were tested for pro-MMP-2 and TIMP-2 content by zymography and ELISA. Plaque extracts were incubated with gel-filtered platelets from healthy volunteers for 2 minutes before the addition of a subthreshold concentration of thrombin receptor activating peptide-6 (TRAP-6) and aggregation was assessed. Moreover, platelet deposition on plaque extracts immobilised on plastic coverslips under high shear-rate flow conditions was measured. Forty-three plaque extracts (53%) potentiated platelet aggregation (+233 ± 26.8%), an effect prevented by three different specific MMP-2 inhibitors (inhibitor II, TIMP-2, moAb anti-MMP-2). The pro-MMP-2/TIMP-2 ratio of plaques potentiating platelet aggregation was significantly higher than that of plaques not potentiating it (3.67 ± 1.21 vs 1.01 ± 0.43, p<0.05). Moreover, the platelet aggregation-potentiating effect, the active-MMP-2 content and the active MMP-2/pro-MMP-2 ratio of plaque extracts were significantly higher in plaques from patients who developed a subsequent major cardiovascular event. In conclusion, atherosclerotic plaques exert a prothrombotic effect by potentiating platelet activation due to their content of MMP-2; an elevated MMP-2 activity in plaques is associated with a higher rate of subsequent ischaemic cerebrovascular events.

Immobilization of (dd)heteronuclear hexacyanoferrates(II) in a gelatin matrix

International Nuclear Information System (INIS)

Mikhajlov, O.V.

2008-01-01

Data pertinent to potentiality of preparing salts of (dd)heteronuclear hexacyanoferrates(II) with(M 1 ) II and (M 2 ) II (M 1 , M 2 = Mn, Co, Ni, Cu, Zn, Cd) as a result of contact between M 1 2 [Fe(CN) 6 ] immobilized in a gelatin matrix and aqueous solutions of metal chlorides have been systematized and summarized. The decisive role of the gelatin matrix, performing the function of an organizing system in formation of (dd)heteronuclear hexacyanoferrates(II) of metals, has been pointed out [ru

In Situ Gold Nanoparticle Gradient Formation in a 3D Meso- and Macroporous Polymer Matrix.

Science.gov (United States)

Penders, Jelle; Rajasekharan, Anand K; Hulander, Mats; Andersson, Martin

2017-08-01

Herein, the development and characterization of a 3D gradient structure of gold nanoparticles is described. The gradient of gold nanoparticles is made in situ in a macroporous nonionic block copolymer hydrogel matrix, through gold ion diffusion control. The polymer provides a matrix for diffusion of gold ions, acts as a template for controlling nanoparticle growth, and facilitates the in situ reduction of gold ions to gold nanoparticles. A clear gradient in gold nanoparticles is observed across the 3D space of the polymer matrix using scanning electron microscopy, fluorescence microscopy, atomic force microscopy, and thermogravimetric analysis. The particle gradient is further functionalized with both hydrophobic and hydrophilic groups via thiol-gold linkage to demonstrate the ability to form gradients with different chemical functionalities. Using additive manufacturing, the polymer can also be printed as a porous network with possible applications for 3D cell culturing in, e.g., biomaterials research. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Positive/negative liquid secondary ion mass spectrometry of Ln-EDTA (1:1) complexes. Formation of molecular ion adducts with neutral species of the matrix or Ln-EDTA

International Nuclear Information System (INIS)

Plaziak, A.S.; Lis, S.; Elbanowski, M.

1992-01-01

The mass spectra of 1:1 complexes of EDTA with lanthanide cations (Ln=Sm, Eu, Gd, Tb or Dy) upon positive/negative LSIMS are presented. In glycerol used as a matrix, adduct-ions such as [M+H] + , [M+H+nGly] + , [2M+H] + , [2M+H+Gly] + (positive LSIMS) or [M-H] - , [M-H+nGly] - , [2M-H] - , [2M-H+Gly] - (negative LSIMS), where n=1-3, are formed. Reactions leading to the formation of adduct-ions are suggested. (authors)

Efficient implementations of block sparse matrix operations on shared memory vector machines

International Nuclear Information System (INIS)

Washio, T.; Maruyama, K.; Osoda, T.; Doi, S.; Shimizu, F.

2000-01-01

In this paper, we propose vectorization and shared memory-parallelization techniques for block-type random sparse matrix operations in finite element (FEM) applications. Here, a block corresponds to unknowns on one node in the FEM mesh and we assume that the block size is constant over the mesh. First, we discuss some basic vectorization ideas (the jagged diagonal (JAD) format and the segmented scan algorithm) for the sparse matrix-vector product. Then, we extend these ideas to the shared memory parallelization. After that, we show that the techniques can be applied not only to the sparse matrix-vector product but also to the sparse matrix-matrix product, the incomplete or complete sparse LU factorization and preconditioning. Finally, we report the performance evaluation results obtained on an NEC SX-4 shared memory vector machine for linear systems in some FEM applications. (author)

MoS{sub 2}/Ag nanohybrid: A novel matrix with synergistic effect for small molecule drugs analysis by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yaju, E-mail: daisy19900911@hotmail.com [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 (China); Deng, Guoqing, E-mail: denggqq@sina.com [Department of Polymer Science and Engineering, Nanjing University, Nanjing, 210023 (China); Liu, Xiaohui, E-mail: lcswyh@126.com [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 (China); Sun, Liang, E-mail: sunliang@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 (China); Li, Hui, E-mail: lihui@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 (China); Cheng, Quan, E-mail: quan.cheng@ucr.edu [Department of Chemistry, University of California, Riverside, CA, 92521 (United States); Xi, Kai, E-mail: xikai@nju.edu.cn [Department of Polymer Science and Engineering, Nanjing University, Nanjing, 210023 (China); Xu, Danke, E-mail: xudanke@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 (China)

2016-09-21

This paper reports a facile synthesis of molybdenum disulfide nanosheets/silver nanoparticles (MoS{sub 2}/Ag) hybrid and its use as an effective matrix in negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The nanohybrid exerts a strong synergistic effect, leading to high performance detection of small molecule analytes including amino acids, peptides, fatty acids and drugs. The enhancement of laser desorption/ionization (LDI) efficiency is largely attributed to the high surface roughness and large surface area for analyte adsorption, better dispersibility, increased thermal conductivity and enhanced UV energy absorption as compared to pure MoS{sub 2}. Moreover, both Ag nanoparticles and the edge of the MoS{sub 2} layers function as deprotonation sites for proton capture, facilitating the charging process in negative ion mode and promoting formation of negative ions. As a result, the MoS{sub 2}/Ag nanohybrid proves to be a highly attractive matrix in MALDI-TOF MS, with desired features such as high desorption/ionization efficiency, low fragmentation interference, high salt tolerance, and no sweet-spots for mass signal. These characteristic properties allowed for simultaneous analysis of eight different drugs and quantification of acetylsalicylic acid in the spiked human serum. This work demonstrates for the first time the fabrication and application of a novel MoS{sub 2}/Ag hybrid, and provides a new platform for use in the rapid and high throughput analysis of small molecules by mass spectrometry. - Highlights: • MoS{sub 2}/Ag nanohybrid was applied as a novel matrix in negative-ion MALDI-TOF MS. • The MoS{sub 2}/Ag nanohybrid exerted synergistic effect on the detection of small molecules. • The MoS{sub 2}/Ag nanohybrid showed good signal reproducibility and low background interferences comparing to organic matrices. • MoS{sub 2}/Ag allows simultaneous analysis of multiple drugs and quantification of

Feedback amplification of fibrosis through matrix stiffening and COX-2 suppression

Science.gov (United States)

Liu, Fei; Mih, Justin D.; Shea, Barry S.; Kho, Alvin T.; Sharif, Asma S.; Tager, Andrew M.

2010-01-01

Tissue stiffening is a hallmark of fibrotic disorders but has traditionally been regarded as an outcome of fibrosis, not a contributing factor to pathogenesis. In this study, we show that fibrosis induced by bleomycin injury in the murine lung locally increases median tissue stiffness sixfold relative to normal lung parenchyma. Across this pathophysiological stiffness range, cultured lung fibroblasts transition from a surprisingly quiescent state to progressive increases in proliferation and matrix synthesis, accompanied by coordinated decreases in matrix proteolytic gene expression. Increasing matrix stiffness strongly suppresses fibroblast expression of COX-2 (cyclooxygenase-2) and synthesis of prostaglandin E2 (PGE2), an autocrine inhibitor of fibrogenesis. Exogenous PGE2 or an agonist of the prostanoid EP2 receptor completely counteracts the proliferative and matrix synthetic effects caused by increased stiffness. Together, these results demonstrate a dominant role for normal tissue compliance, acting in part through autocrine PGE2, in maintaining fibroblast quiescence and reveal a feedback relationship between matrix stiffening, COX-2 suppression, and fibroblast activation that promotes and amplifies progressive fibrosis. PMID:20733059

Activity of matrix metalloproteinases during antimycobacterial therapy in mice with simulated tuberculous inflammation.

Science.gov (United States)

Sumenkova, D V; Russkikh, G S; Poteryaeva, O N; Polyakov, L M; Panin, L E

2013-05-01

Matrix metalloproteinases are shown to be involved in the pathogenesis of tuberculosis inflammation. In the early stages of BCG-granuloma formation in mouse liver and lungs, the serum levels of matrix metalloproteinases 2 and 7 increased by 4.5 times and remained unchanged while the pathology developed. Antimycobacterial therapy with isoniazid reduced enzyme activity almost to the level of intact control. The decrease in activity of matrix metalloproteinases 2 and 7 that play the most prominent role in the development of destructive forms of tuberculosis is of great therapeutic importance.

Metal matrix coated fiber composites and the methods of manufacturing such composites

Science.gov (United States)

Weeks, J.K. Jr.; Gensse, C.

1993-09-14

A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials. 8 figures.

Positron scattering by atomic hydrogen including positronium formation

International Nuclear Information System (INIS)

Higgins, K.; Burke, P.G.

1993-01-01

Positron scattering by atomic hydrogen including positronium formation has been formulated using the R-matrix method and a general computer code written. Partial wave elastic and ground state positronium formation cross sections have been calculated for L ≤ 6 using a six-state approximation which includes the ground state and the 2s and 2p pseudostates of both hydrogen and positronium. The elastic scattering results obtained are in good agreement with those derived from a highly accurate calculation based upon the intermediate energy R-matrix approach. As in a previous coupled-channel static calculation, resonance effects are observed at intermediate energies in the S-wave positronium formation cross section. However, in the present results, the dominant resonance arises in the P-wave cross sections at an energy of 2.73 Ryd and with a width of 0.19 Ryd. (author)

Effects of cell-attachment and extracellular matrix on bone formation in vivo in collagen-hydroxyapatite scaffolds.

Science.gov (United States)

Villa, Max M; Wang, Liping; Rowe, David W; Wei, Mei

2014-01-01

Cell-based tissue engineering can be used to replace missing or damaged bone, but the optimal methods for delivering therapeutic cells to a bony defect have not yet been established. Using transgenic reporter cells as a donor source, two different collagen-hydroxyapatite (HA) scaffolds, and a critical-size calvarial defect model, we investigated the effect of a cell-attachment period prior to implantation, with or without an extracellular matrix-based seeding suspension, on cell engraftment and osteogenesis. When quantitatively compared, the in-house scaffold implanted immediately had a higher mean radiopacity than in-house scaffolds incubated overnight. Both scaffold types implanted immediately had significantly higher area fractions of donor cells, while the in-house collagen-HA scaffolds implanted immediately had higher area fractions of the mineralization label compared with groups incubated overnight. When the cell loading was compared in vitro for each delivery method using the in-house scaffold, immediate loading led to higher numbers of delivered cells. Immediate loading may be preferable in order to ensure robust bone formation in vivo. The use of a secondary ECM carrier improved the distribution of donor cells only when a pre-attachment period was applied. These results have improved our understanding of cell delivery to bony defects in the context of in vivo outcomes.

Extending the bidding format to promote demand response

International Nuclear Information System (INIS)

Liu, Yanchao; Holzer, Jesse T.; Ferris, Michael C.

2015-01-01

We propose an extended bidding structure to allow more realistic demand characteristics and behaviors to be expressed via flexible bids. In today's ISO-run energy markets, demand bid formats are all separable over time. However, a significant and growing segment of demand can be shifted across time and therefore has no way to bid its true valuation of consumption. We propose additional bid types that allow deferrable, adjustable and storage-type loads to better express their value, and thus elicit demand response in the most natural way – via direct participation in the market. We show that the additional bid types are easily incorporated into the existing market with no technological barrier and that they preserve the market's efficiency and incentive-compatibility properties. Using real market data, we give a numerical demonstration that the extended bid format could substantially increase social welfare, and also present additional insight on storage expansion scenarios. - Highlights: • Three new bid types are proposed to enrich demand-side participation. • Time value of electricity demand can be clearly conveyed to central dispatcher. • The extended format preserves market efficiency and incentive compatibility. • Energy storage is most effective to neutralize price volatility, with a limitation.

Methylobacterium Species Promoting Rice and Barley Growth and Interaction Specificity Revealed with Whole-Cell Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF/MS Analysis.

Directory of Open Access Journals (Sweden)

Akio Tani

Full Text Available Methylobacterium species frequently inhabit plant surfaces and are able to utilize the methanol emitted from plants as carbon and energy sources. As some of the Methylobacterium species are known to promote plant growth, significant attention has been paid to the mechanism of growth promotion and the specificity of plant-microbe interactions. By screening our Methylobacterium isolate collection for the high growth promotion effect in vitro, we selected some candidates for field and pot growth tests for rice and barley, respectively. We found that inoculation resulted in better ripening of rice seeds, and increased the size of barley grains but not the total yield. In addition, using whole-cell matrix-assister laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS analysis, we identified and classified Methylobacterium isolates from Methylobacterium-inoculated rice plants. The inoculated species could not be recovered from the rice plants, and in some cases, the Methylobacterium community structure was affected by the inoculation, but not with predomination of the inoculated species. The isolates from non-inoculated barley of various cultivars grown in the same field fell into just two species. These results suggest that there is a strong selection pressure at the species level of Methylobacterium residing on a given plant species, and that selection of appropriate species that can persist on the plant is important to achieve growth promotion.

Inhibition of matrix metalloproteinase-14 in osteosarcoma cells by clodronate

NARCIS (Netherlands)

Heikkilä, P.; Teronen, O.; Hirn, M.Y.; Sorsa, T.; Tervahartiala, T.; Salo, T.; Konttinen, Y.T.; Halttunen, T.; Moilanen, M.; Hanemaaijer, R.; Laitinen, M.

2003-01-01

Background. Bisphosphonates reduce the bone metastasis formation and angiogenesis but the exact molecular mechanisms involved are unclear. Progelatinase A (proMMP-2; 78 KDa) is activated up during the tumor spread and metastasis by a cell surface-associated matrix metalloproteinase (membrane-type

Matrix-isolation studies on the radiation-induced chemistry in H₂O/CO₂ systems: reactions of oxygen atoms and formation of HOCO radical.

Science.gov (United States)

Ryazantsev, Sergey V; Feldman, Vladimir I

2015-03-19

The radiation-induced transformations occurring upon X-ray irradiation of solid CO2/H2O/Ng systems (Ng = Ar, Kr, Xe) at 8-10 K and subsequent annealing up to 45 K were studied by Fourier transform infrared spectroscopy. The infrared (IR) spectra of deposited matrices revealed the presence of isolated monomers, dimers, and intermolecular H2O···CO2 complexes. Irradiation resulted in effective decomposition of matrix-isolated carbon dioxide and water yielding CO molecules and OH radicals, respectively. Annealing of the irradiated samples led to formation of O3, HO2, and a number of xenon hydrides of HXeY type (in the case of xenon matrices). The formation of these species was used for monitoring of the postirradiation thermally induced chemical reactions involving O and H atoms generated by radiolysis. It was shown that the radiolysis of CO2 in noble-gas matrices produced high yields of stabilized oxygen atoms. In all cases, the temperatures at which O atoms become mobile and react are lower than those of H atoms. Dynamics and reactivity of oxygen atoms was found to be independent of the precursor nature. In addition, the formation of HOCO radicals was observed in all the noble-gas matrices at remarkably low temperatures. The IR spectra of HOCO and DOCO were first characterized in krypton and xenon matrices. It was concluded that the formation of HOCO was mainly due to the radiation-induced evolution of the weakly bound H2O···CO2 complexes. This result indicates the significance of weak intermolecular interactions in the radiation-induced chemical processes in inert low-temperature media.

SclR, a basic helix-loop-helix transcription factor, regulates hyphal morphology and promotes sclerotial formation in Aspergillus oryzae.

Science.gov (United States)

Jin, Feng Jie; Takahashi, Tadashi; Matsushima, Ken-ichiro; Hara, Seiichi; Shinohara, Yasutomo; Maruyama, Jun-ichi; Kitamoto, Katsuhiko; Koyama, Yasuji

2011-07-01

Most known basic-region helix-loop-helix (bHLH) proteins belong to a superfamily of transcription factors often involved in the control of growth and differentiation. Therefore, inappropriate expression of genes encoding bHLH proteins is frequently associated with developmental dysfunction. In our previously reported study, a novel bHLH protein-encoding gene (AO090011000215) of Aspergillus oryzae was identified. The gene-disrupted strain was found to produce dense conidia, but sparse sclerotia, relative to the parent strain. Here, to further analyze its function, we generated an overexpressing strain using the A. oryzae amyB gene promoter. Genetic overexpression led to a large number of initial hyphal aggregations and then the formation of mature sclerotia; it was therefore designated sclR (sclerotium regulator). At the same time, the sclR-overexpressing strain also displayed both delayed and decreased conidiation. Scanning electron microscopy indicated that the aerial hyphae of the sclR-overexpressing strain were extremely branched and intertwined with each other. In the generation of the SclR-enhanced green fluorescent protein (EGFP) expression strain, the SclR-EGFP protein fusion was conditionally detected in the nuclei. In addition, the loss of sclR function led to rapid protein degradation and cell lysis in dextrin-polypeptone-yeast extract liquid medium. Taken together, these observations indicate that SclR plays an important role in hyphal morphology, asexual conidiospore formation, and the promotion of sclerotial production, even retaining normal cell function, at least in submerged liquid culture.

Matrix acidification in carbonate reservoirs; Acidificacoes matriciais em reservatorios carbonaticos

Energy Technology Data Exchange (ETDEWEB)

Martins, Marcio de Oliveira [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

2012-07-01

Carbonate reservoirs are characterized by great diversity of its properties, including permeability and porosity. When submitted to matrix acidification, if no effort is employed, acid will tend to consume carbonates where permeability and porosity are higher, further increasing conductivity of these sites and also increasing permeability and porosity contrast existing before acid effects on formation. That would give limited production as result of small effective producer zone extent, with probable underutilization of potential reservoirs productivity. To overcome this effect and to achieve greater coverage of treatments, divergence techniques should be applied, including associations of them. This paper presents divergence techniques performed in matrix acidification of Campos and Espirito Santo basins wells, which represent great structural diversity and, as consequence, a significant range of situations. Formations tests results are analyzed to verify diversion systems effectiveness, and how they contribute to the growth of productive potential. (author)

Modeling the influence of interaction layer formation on thermal conductivity of U–Mo dispersion fuel

International Nuclear Information System (INIS)

Burkes, Douglas E.; Casella, Andrew M.; Huber, Tanja K.

2015-01-01

Highlights: • Hsu equation provides best thermal conductivity estimate of U–Mo dispersion fuel. • Simple model considering interaction layer formation was coupled with Hsu equation. • Interaction layer thermal conductivity is not the most important attribute. • Effective thermal conductivity is mostly influenced by interaction layer formation. • Fuel particle distribution also influences the effective thermal conductivity. - Abstract: The Global Threat Reduction Initiative Program continues to develop existing and new test reactor fuels to achieve the maximum attainable uranium loadings to support the conversion of a number of the world’s remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of a fuel design that consists of a uranium–molybdenum (U–Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel and can be influenced by interaction layer formation between the dispersed phase and matrix, porosity that forms during fabrication of the fuel plates or rods, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation, dispersed particle size, and volume fraction of dispersed phase in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be as important in determining the effective conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the dispersed particle distribution by minimizing interaction

Genotypic and Phenotypic Characteristics Associated with Biofilm Formation by Human Clinical Escherichia coli Isolates of Different Pathotypes.

Science.gov (United States)

Schiebel, Juliane; Böhm, Alexander; Nitschke, Jörg; Burdukiewicz, Michał; Weinreich, Jörg; Ali, Aamir; Roggenbuck, Dirk; Rödiger, Stefan; Schierack, Peter

2017-12-15

Bacterial biofilm formation is a widespread phenomenon and a complex process requiring a set of genes facilitating the initial adhesion, maturation, and production of the extracellular polymeric matrix and subsequent dispersal of bacteria. Most studies on Escherichia coli biofilm formation have investigated nonpathogenic E. coli K-12 strains. Due to the extensive focus on laboratory strains in most studies, there is poor information regarding biofilm formation by pathogenic E. coli isolates. In this study, we genotypically and phenotypically characterized 187 human clinical E. coli isolates representing various pathotypes (e.g., uropathogenic, enteropathogenic, and enteroaggregative E. coli ). We investigated the presence of biofilm-associated genes ("genotype") and phenotypically analyzed the isolates for motility and curli and cellulose production ("phenotype"). We developed a new screening method to examine the in vitro biofilm formation ability. In summary, we found a high prevalence of biofilm-associated genes. However, we could not detect a biofilm-associated gene or specific phenotype correlating with the biofilm formation ability. In contrast, we did identify an association of increased biofilm formation with a specific E. coli pathotype. Enteroaggregative E. coli (EAEC) was found to exhibit the highest capacity for biofilm formation. Using our image-based technology for the screening of biofilm formation, we demonstrated the characteristic biofilm formation pattern of EAEC, consisting of thick bacterial aggregates. In summary, our results highlight the fact that biofilm-promoting factors shown to be critical for biofilm formation in nonpathogenic strains do not reflect their impact in clinical isolates and that the ability of biofilm formation is a defined characteristic of EAEC. IMPORTANCE Bacterial biofilms are ubiquitous and consist of sessile bacterial cells surrounded by a self-produced extracellular polymeric matrix. They cause chronic and device

σ and η Phase formation in advanced polycrystalline Ni-base superalloys

Energy Technology Data Exchange (ETDEWEB)

Antonov, Stoichko, E-mail: santonov@hawk.iit.edu [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States); Huo, Jiajie; Feng, Qiang [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Isheim, Dieter; Seidman, David N. [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208 (United States); Northwestern University Center for Atom Probe Tomography (NUCAPT), 2220 Campus Drive, Evanston, IL 60208 (United States); Helmink, Randolph C.; Sun, Eugene [Rolls-Royce Corporation, 450 S. Meridian Street, Indianapolis, IN 46225 (United States); Tin, Sammy [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States)

2017-02-27

In polycrystalline Ni-base superalloys, grain boundary precipitation of secondary phases can be significant due to the effects they pose on the mechanical properties. As new alloying concepts for polycrystalline Ni-base superalloys are being developed to extend their temperature capability, the effect of increasing levels of Nb alloying additions on long term phase stability and the formation of topologically close packed (TCP) phases needs to be studied. Elevated levels of Nb can result in increased matrix supersaturation and promote the precipitation of secondary phases. Long term thermal exposures on two experimental powder processed Ni-base superalloys containing various levels of Nb were completed to assess the stability and precipitation of TCP phases. It was found that additions of Nb promoted the precipitation of η-Ni{sub 6}AlNb along the grain boundaries in powder processed, polycrystalline Ni-base superalloys, while reduced Nb levels favored the precipitation of blocky Cr and Mo – rich σ phase precipitates along the grain boundary. Evaluation of the thermodynamic stability of these two phases in both alloys using Thermo-calc showed that while σ phase predictions are fairly accurate, predictions of the η phase are limited.

Fabrication of fiber composites with a MAX phase matrix by reactive melt infiltration

International Nuclear Information System (INIS)

Lenz, F; Krenkel, W

2011-01-01

Due to the inherent brittleness of ceramics it is very desirable to increase the damage tolerance of ceramics. The ternary MAX phases are a promising group of materials with high fracture toughness. The topic of this study is the development of ceramic matrix composites (CMCs) with a matrix containing MAX phases, to achieve a damage tolerant structural composite material. For this purpose carbon fiber reinforced preforms with a carbon-titanium carbide matrix (C/C-TiC) were developed and infiltrated with silicon by a pressureless reactive melt infiltration. Finally liquid silicon caused the formation of SiC, TiSi 2 and Ti 3 SiC 2 in the matrix of the composite.

Enamel formation and amelogenesis imperfecta.

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Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

2007-01-01

Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel. Copyright 2007 S. Karger AG, Basel.

Formation of the methodological matrix of the strategic analysis of the enterprise

Directory of Open Access Journals (Sweden)

N.H. Vygovskaya

2018-04-01

Full Text Available The article is devoted to the study of the methodological matrix of the strategic analysis of the enterprise. The aim of this article is to analyze the influence of methodological changes in the 20th century on the methodology of strategic analysis; critical assessment and generalization of scientific approaches to its methods. Evaluation of scientific works on analysis made it possible to identify such problems in the methodology of strategic analysis as the lack of consideration of the features of strategic analysis in the formation of its methods, which often leads to confusion of methods of financial (economic, thrifty analysis; failure to use the fact that the strategic analysis contains, besides the methods of analyzing the internal and external environment, the methods of forecast analysis aimed at forming the strategy for the development of the enterprise; identification of the concepts «image», «reception», «method» of analysis; multidirectionality and indistinctness of signs of classification of methods of strategic analysis; blind copying of foreign methods of application of techniques and methods of strategic analysis without taking into account the specifics of domestic economic conditions. The expediency of using the system approach in forming the methodological design of strategic analysis is proved, which will allow to combine the methodology as a science of methods (a broad approach to the methods of strategic analysis with methodology as a set of applied methods and methods of analysis (narrow approach to methodology. The use of the system approach allowed to distinguish three levels of the methodology of strategic analysis. The first and second levels of methodology correspond to the level of science, the third level – the practice. When developing the third level of special methods of strategic analysis, an approach is applied that differentiates them depending on the stages of strategic analysis (methods of the stage

Formation of silver nanoparticles inside a soda-lime glass matrix in the presence of a high intensity Ar+ laser beam

International Nuclear Information System (INIS)

Niry, M. D.; Khalesifard, H. R.; Mostafavi-Amjad, J.; Ahangary, A.; Azizian-Kalandaragh, Y.

2012-01-01

Formation and motion of the silver nanoparticles inside an ion-exchanged soda-lime glass in the presence of a focused high intensity continuous wave Ar + laser beam (intensity: 9.2 x 10 4 W/cm 2 ) have been studied in here. One-dimensional diffusion equation has been used to model the diffusion of the silver ions into the glass matrix, and a two-dimensional reverse diffusion model has been introduced to explain the motion of the silver clusters and their migration toward the glass surface in the presence of the laser beam. The results of the mentioned models were in agreement with our measurements on thickness of the ion-exchange layer by means of optical microscopy and recorded morphology of the glass surface around the laser beam axis by using a Mirau interferometer. SEM micrographs were used to extract the size distribution of the migrated silver particles over the glass surface.

Xenogenic (porcine) acellular dermal matrix promotes growth of granulation tissues in the wound healing of Fournier gangrene.

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Zhang, Zhaoxin; Lv, Lei; Mamat, Masut; Chen, Zhao; Zhou, Zhitao; Liu, Lihua; Wang, Zhizhong

2015-01-01

This article investigates the application values of Xenogenic (porcine) acellular dermal matrix (XADM) in preparation of a Fournier gangrene wound bed. Thirty-six consecutive cases of patients with Fournier gangrene between 2002 and 2012 were enrolled in our department of our hospital. The patients were divided into two groups according to different methods of wound bed preparation after surgical débridement, including the experimental group (17 cases) and the control group (19 cases). The wounds in the experimental group were covered with XADM after surgical wound débridement, whereas the wounds were cleaned with hydrogen peroxide and sodium hypochlorite solution (one time/day) in the control group. The wound bed preparation time and hospital stay were then compared in the two groups. The wound preparation time was 13.64 ± 1.46 days and hospitalization period was 26.06 ± 0.83 days in the experimental XADM group. In the control group, the wound bed preparation time and hospitalization period were 22.37 ± 1.38 and 38.11 ± 5.60 days, respectively. The results showed statistical differences between these two groups. When used in wound débridement after Fournier gangrene, XADM protects interecological organizations, promotes the growth of granulation tissues, and maximally retains function and morphology of the perineum and penis.

Matrix Metalloproteinases as Therapeutic Targets for Idiopathic Pulmonary Fibrosis

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Craig, Vanessa J.; Zhang, Li; Hagood, James S.

2015-01-01

Idiopathic pulmonary fibrosis (IPF) is a restrictive lung disease that is associated with high morbidity and mortality. Current medical therapies are not fully effective at limiting mortality in patients with IPF, and new therapies are urgently needed. Matrix metalloproteinases (MMPs) are proteinases that, together, can degrade all components of the extracellular matrix and numerous nonmatrix proteins. MMPs and their inhibitors, tissue inhibitors of MMPs (TIMPs), have been implicated in the pathogenesis of IPF based upon the results of clinical studies reporting elevated levels of MMPs (including MMP-1, MMP-7, MMP-8, and MMP-9) in IPF blood and/or lung samples. Surprisingly, studies of gene-targeted mice in murine models of pulmonary fibrosis (PF) have demonstrated that most MMPs promote (rather than inhibit) the development of PF and have identified diverse mechanisms involved. These mechanisms include MMPs: (1) promoting epithelial-to-mesenchymal transition (MMP-3 and MMP-7); (2) increasing lung levels or activity of profibrotic mediators or reducing lung levels of antifibrotic mediators (MMP-3, MMP-7, and MMP-8); (3) promoting abnormal epithelial cell migration and other aberrant repair processes (MMP-3 and MMP-9); (4) inducing the switching of lung macrophage phenotypes from M1 to M2 types (MMP-10 and MMP-28); and (5) promoting fibrocyte migration (MMP-8). Two MMPs, MMP-13 and MMP-19, have antifibrotic activities in murine models of PF, and two MMPs, MMP-1 and MMP-10, have the potential to limit fibrotic responses to injury. Herein, we review what is known about the contributions of MMPs and TIMPs to the pathogenesis of IPF and discuss their potential as therapeutic targets for IPF. PMID:26121236

Matrix metalloproteinases as therapeutic targets for idiopathic pulmonary fibrosis.

Science.gov (United States)

Craig, Vanessa J; Zhang, Li; Hagood, James S; Owen, Caroline A

2015-11-01

Idiopathic pulmonary fibrosis (IPF) is a restrictive lung disease that is associated with high morbidity and mortality. Current medical therapies are not fully effective at limiting mortality in patients with IPF, and new therapies are urgently needed. Matrix metalloproteinases (MMPs) are proteinases that, together, can degrade all components of the extracellular matrix and numerous nonmatrix proteins. MMPs and their inhibitors, tissue inhibitors of MMPs (TIMPs), have been implicated in the pathogenesis of IPF based upon the results of clinical studies reporting elevated levels of MMPs (including MMP-1, MMP-7, MMP-8, and MMP-9) in IPF blood and/or lung samples. Surprisingly, studies of gene-targeted mice in murine models of pulmonary fibrosis (PF) have demonstrated that most MMPs promote (rather than inhibit) the development of PF and have identified diverse mechanisms involved. These mechanisms include MMPs: (1) promoting epithelial-to-mesenchymal transition (MMP-3 and MMP-7); (2) increasing lung levels or activity of profibrotic mediators or reducing lung levels of antifibrotic mediators (MMP-3, MMP-7, and MMP-8); (3) promoting abnormal epithelial cell migration and other aberrant repair processes (MMP-3 and MMP-9); (4) inducing the switching of lung macrophage phenotypes from M1 to M2 types (MMP-10 and MMP-28); and (5) promoting fibrocyte migration (MMP-8). Two MMPs, MMP-13 and MMP-19, have antifibrotic activities in murine models of PF, and two MMPs, MMP-1 and MMP-10, have the potential to limit fibrotic responses to injury. Herein, we review what is known about the contributions of MMPs and TIMPs to the pathogenesis of IPF and discuss their potential as therapeutic targets for IPF.

Interaction between the enamel matrix proteins amelogenin and ameloblastin

International Nuclear Information System (INIS)

Ravindranath, Hanumanth H.; Chen, Li-Sha; Zeichner-David, Margaret; Ishima, Rieko; Ravindranath, Rajeswari M.H.

2004-01-01

Enamel matrix consists of amelogenin and non-amelogenins. Though amelogenin is not involved in nucleation of minerals, the enamel mineralization is impaired when amelogenin or other matrix protein (ameloblastin/enamelin) genes are mutated. We hypothesize that amelogenin may promote enamel mineralization by interacting with the calcium-binding matrix proteins. Specific binding of amelogenin to N-acetylglucosamine (GlcNAc), GlcNAc-mimicking peptides (GMps), and their carrier proteins and the identification of amelogenin-trityrosyl-motif-peptide (ATMP) as a GlcNAc/GMp-binding domain in amelogenin favor the hypothesis. This study tested the interaction of amelogenin with ameloblastin, a carrier of GMp sequence at intermittent sites. Neither GlcNAc nor sialic acids were identified in the recombinant-ameloblastin. Amelogenin bound to recombinant-ameloblastin in both Western blots and in ELISA. More specifically, [ 3 H]ATMP bound to both recombinant and native ameloblastins. Dosimetry and Scatchard analyses showed the specific interaction between ATMP and ameloblastin, suggesting that amelogenin may interact with ameloblastin to form a heteromolecular assembly

Interaction between the enamel matrix proteins amelogenin and ameloblastin.

Science.gov (United States)

Ravindranath, Hanumanth H; Chen, Li-Sha; Zeichner-David, Margaret; Ishima, Rieko; Ravindranath, Rajeswari M H

2004-10-22

Enamel matrix consists of amelogenin and non-amelogenins. Though amelogenin is not involved in nucleation of minerals, the enamel mineralization is impaired when amelogenin or other matrix protein (ameloblastin/enamelin) genes are mutated. We hypothesize that amelogenin may promote enamel mineralization by interacting with the calcium-binding matrix proteins. Specific binding of amelogenin to N-acetylglucosamine (GlcNAc), GlcNAc-mimicking peptides (GMps), and their carrier proteins and the identification of amelogenin-trityrosyl-motif-peptide (ATMP) as a GlcNAc/GMp-binding domain in amelogenin favor the hypothesis. This study tested the interaction of amelogenin with ameloblastin, a carrier of GMp sequence at intermittent sites. Neither GlcNAc nor sialic acids were identified in the recombinant-ameloblastin. Amelogenin bound to recombinant-ameloblastin in both Western blots and in ELISA. More specifically, [(3)H]ATMP bound to both recombinant and native ameloblastins. Dosimetry and Scatchard analyses showed the specific interaction between ATMP and ameloblastin, suggesting that amelogenin may interact with ameloblastin to form a heteromolecular assembly.

Cartilage oligomeric matrix protein enhances matrix assembly during chondrogenesis of human mesenchymal stem cells.

Science.gov (United States)

Haleem-Smith, Hana; Calderon, Raul; Song, Yingjie; Tuan, Rocky S; Chen, Faye H

2012-04-01

Cartilage oligomeric matrix protein/thrombospondin-5 (COMP/TSP5) is an abundant cartilage extracellular matrix (ECM) protein that interacts with major cartilage ECM components, including aggrecan and collagens. To test our hypothesis that COMP/TSP5 functions in the assembly of the ECM during cartilage morphogenesis, we have employed mesenchymal stem cell (MSC) chondrogenesis in vitro as a model to examine the effects of COMP over-expression on neo-cartilage formation. Human bone marrow-derived MSCs were transfected with either full-length COMP cDNA or control plasmid, followed by chondrogenic induction in three-dimensional pellet or alginate hydrogel culture. MSC chondrogenesis and ECM production was estimated based on quantitation of sulfated glycosaminoglycan (sGAG) accumulation, immunohistochemistry of the presence and distribution of cartilage ECM proteins, and real-time RT-PCR analyis of mRNA expression of cartilage markers. Our results showed that COMP over-expression resulted in increased total sGAG content during the early phase of MSC chondrogenesis, and increased immuno-detectable levels of aggrecan and collagen type II in the ECM of COMP-transfected pellet and alginate cultures, indicating more abundant cartilaginous matrix. COMP transfection did not significantly increase the transcript levels of the early chondrogenic marker, Sox9, or aggrecan, suggesting that enhancement of MSC cartilage ECM was effected at post-transcriptional levels. These findings strongly suggest that COMP functions in mesenchymal chondrogenesis by enhancing cartilage ECM organization and assembly. The action of COMP is most likely mediated not via direct changes in cartilage matrix gene expression but via interactions of COMP with other cartilage ECM proteins, such as aggrecan and collagens, that result in enhanced assembly and retention.

CARTILAGE OLIGOMERIC MATRIX PROTEIN ENHANCES MATRIX ASSEMBLY DURING CHONDROGENESIS OF HUMAN MESENCHYMAL STEM CELLS

Science.gov (United States)

Haleem-Smith, Hana; Calderon, Raul; Song, Yingjie; Tuan, Rocky S.; Chen, Faye H.

2011-01-01

Cartilage oligomeric matrix protein/thrombospondin-5 (COMP/TSP5) is an abundant cartilage extracellular matrix (ECM) protein that interacts with major cartilage ECM components, including aggrecan and collagens. To test our hypothesis that COMP/TSP5 functions in the assembly of the ECM during cartilage morphogenesis, we have employed mesenchymal stem cell (MSC) chondrogenesis in vitro as a model to examine the effects of COMP over-expression on neo-cartilage formation. Human bone marrow-derived MSCs were transfected with either full-length COMP cDNA or control plasmid, followed by chondrogenic induction in three-dimensional pellet or alginate-hydrogel culture. MSC chondrogenesis and ECM production was estimated based on quantitation of sulfated glycosaminoglycan (sGAG) accumulation, immunohistochemistry of the presence and distribution of cartilage ECM proteins, and real-time RT-PCR analyis of mRNA expression of cartilage markers. Our results showed that COMP over-expression resulted in increased total sGAG content during the early phase of MSC chondrogenesis, and increased immuno-detectable levels of aggrecan and collagen type II in the ECM of COMP-transfected pellet and alginate cultures, indicating more abundant cartilaginous matrix. COMP transfection did not significantly increase the transcript levels of the early chondrogenic marker, Sox9, or aggrecan, suggesting that enhancement of MSC cartilage ECM was effected at post-transcriptional levels. These findings strongly suggest that COMP functions in mesenchymal chondrogenesis by enhancing cartilage ECM organization and assembly. The action of COMP is most likely mediated not via direct changes in cartilage matrix gene expression but via interactions of COMP with other cartilage ECM proteins, such as aggrecan and collagens, that result in enhanced assembly and retention. PMID:22095699

Laminin and Matrix metalloproteinase 11 regulate Fibronectin levels in the zebrafish myotendinous junction.

Science.gov (United States)

Jenkins, Molly H; Alrowaished, Sarah S; Goody, Michelle F; Crawford, Bryan D; Henry, Clarissa A

2016-01-01

Remodeling of the extracellular matrix (ECM) regulates cell adhesion as well as signaling between cells and their microenvironment. Despite the importance of tightly regulated ECM remodeling for normal muscle development and function, mechanisms underlying ECM remodeling in vivo remain elusive. One excellent paradigm in which to study ECM remodeling in vivo is morphogenesis of the myotendinous junction (MTJ) during zebrafish skeletal muscle development. During MTJ development, there are dramatic shifts in the primary components comprising the MTJ matrix. One such shift involves the replacement of Fibronectin (Fn)-rich matrix, which is essential for both somite and early muscle development, with laminin-rich matrix essential for normal function of the myotome. Here, we investigate the mechanism underlying this transition. We show that laminin polymerization indirectly promotes Fn downregulation at the MTJ, via a matrix metalloproteinase 11 (Mmp11)-dependent mechanism. Laminin deposition and organization is required for localization of Mmp11 to the MTJ, where Mmp11 is both necessary and sufficient for Fn downregulation in vivo. Furthermore, reduction of residual Mmp11 in laminin mutants promotes a Fn-rich MTJ that partially rescues skeletal muscle architecture. These results identify a mechanism for Fn downregulation at the MTJ, highlight crosstalk between laminin and Fn, and identify a new in vivo function for Mmp11. Taken together, our data demonstrate a novel signaling pathway mediating Fn downregulation. Our data revealing new regulatory mechanisms that guide ECM remodeling during morphogenesis in vivo may inform pathological conditions in which Fn is dysregulated.

Dynamic 3D cell rearrangements guided by a fibronectin matrix underlie somitogenesis.

Directory of Open Access Journals (Sweden)

Gabriel G Martins

Full Text Available Somites are transient segments formed in a rostro-caudal progression during vertebrate development. In chick embryos, segmentation of a new pair of somites occurs every 90 minutes and involves a mesenchyme-to-epithelium transition of cells from the presomitic mesoderm. Little is known about the cellular rearrangements involved, and, although it is known that the fibronectin extracellular matrix is required, its actual role remains elusive. Using 3D and 4D imaging of somite formation we discovered that somitogenesis consists of a complex choreography of individual cell movements. Epithelialization starts medially with the formation of a transient epithelium of cuboidal cells, followed by cell elongation and reorganization into a pseudostratified epithelium of spindle-shaped epitheloid cells. Mesenchymal cells are then recruited to this medial epithelium through accretion, a phenomenon that spreads to all sides, except the lateral side of the forming somite, which epithelializes by cell elongation and intercalation. Surprisingly, an important contribution to the somite epithelium also comes from the continuous egression of mesenchymal cells from the core into the epithelium via its apical side. Inhibition of fibronectin matrix assembly first slows down the rate, and then halts somite formation, without affecting pseudopodial activity or cell body movements. Rather, cell elongation, centripetal alignment, N-cadherin polarization and egression are impaired, showing that the fibronectin matrix plays a role in polarizing and guiding the exploratory behavior of somitic cells. To our knowledge, this is the first 4D in vivo recording of a full mesenchyme-to-epithelium transition. This approach brought new insights into this event and highlighted the importance of the extracellular matrix as a guiding cue during morphogenesis.

Extracellular Matrix-Mediated Maturation of Human Pluripotent Stem Cell-Derived Cardiac Monolayer Structure and Electrophysiological Function.

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Herron, Todd J; Rocha, Andre Monteiro Da; Campbell, Katherine F; Ponce-Balbuena, Daniela; Willis, B Cicero; Guerrero-Serna, Guadalupe; Liu, Qinghua; Klos, Matt; Musa, Hassan; Zarzoso, Manuel; Bizy, Alexandra; Furness, Jamie; Anumonwo, Justus; Mironov, Sergey; Jalife, José

2016-04-01

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) monolayers generated to date display an immature embryonic-like functional and structural phenotype that limits their utility for research and cardiac regeneration. In particular, the electrophysiological function of hPSC-CM monolayers and bioengineered constructs used to date are characterized by slow electric impulse propagation velocity and immature action potential profiles. Here, we have identified an optimal extracellular matrix for significant electrophysiological and structural maturation of hPSC-CM monolayers. hPSC-CM plated in the optimal extracellular matrix combination have impulse propagation velocities ≈2× faster than previously reported (43.6±7.0 cm/s; n=9) and have mature cardiomyocyte action potential profiles, including hyperpolarized diastolic potential and rapid action potential upstroke velocity (146.5±17.7 V/s; n=5 monolayers). In addition, the optimal extracellular matrix promoted hypertrophic growth of cardiomyocytes and the expression of key mature sarcolemmal (SCN5A, Kir2.1, and connexin43) and myofilament markers (cardiac troponin I). The maturation process reported here relies on activation of integrin signaling pathways: neutralization of β1 integrin receptors via blocking antibodies and pharmacological blockade of focal adhesion kinase activation prevented structural maturation. Maturation of human stem cell-derived cardiomyocyte monolayers is achieved in a 1-week period by plating cardiomyocytes on PDMS (polydimethylsiloxane) coverslips rather than on conventional 2-dimensional cell culture formats, such as glass coverslips or plastic dishes. Activation of integrin signaling and focal adhesion kinase is essential for significant maturation of human cardiac monolayers. © 2016 American Heart Association, Inc.

The exopolysaccharide matrix: a virulence determinant of cariogenic biofilm.

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Koo, H; Falsetta, M L; Klein, M I

2013-12-01

Many infectious diseases in humans are caused or exacerbated by biofilms. Dental caries is a prime example of a biofilm-dependent disease, resulting from interactions of microorganisms, host factors, and diet (sugars), which modulate the dynamic formation of biofilms on tooth surfaces. All biofilms have a microbial-derived extracellular matrix as an essential constituent. The exopolysaccharides formed through interactions between sucrose- (and starch-) and Streptococcus mutans-derived exoenzymes present in the pellicle and on microbial surfaces (including non-mutans) provide binding sites for cariogenic and other organisms. The polymers formed in situ enmesh the microorganisms while forming a matrix facilitating the assembly of three-dimensional (3D) multicellular structures that encompass a series of microenvironments and are firmly attached to teeth. The metabolic activity of microbes embedded in this exopolysaccharide-rich and diffusion-limiting matrix leads to acidification of the milieu and, eventually, acid-dissolution of enamel. Here, we discuss recent advances concerning spatio-temporal development of the exopolysaccharide matrix and its essential role in the pathogenesis of dental caries. We focus on how the matrix serves as a 3D scaffold for biofilm assembly while creating spatial heterogeneities and low-pH microenvironments/niches. Further understanding on how the matrix modulates microbial activity and virulence expression could lead to new approaches to control cariogenic biofilms.

Hydrogen-bond-driven electrophilic activation for selectivity control: scope and limitations of fluorous alcohol-promoted selective formation of 1,2-disubstituted benzimidazoles and mechanistic insight for rationale of selectivity.

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Chebolu, Rajesh; Kommi, Damodara N; Kumar, Dinesh; Bollineni, Narendra; Chakraborti, Asit K

2012-11-16

Hydrogen-bond-driven electrophilic activation for selectivity control during competitive formation of 1,2-disubstituted and 2-substituted benzimidazoles from o-phenylenediamine and aldehydes is reported. The fluorous alcohols trifluoroethanol and hexafluoro-2-propanol efficiently promote the cyclocondensation of o-phenylenediamine with aldehydes to afford selectively the 1,2-disubstituted benzimidazoles at rt in short times. A mechanistic insight is invoked by NMR, mass spectrometry, and chemical studies to rationalize the selectivity. The ability of the fluorous alcohols in promoting the reaction and controlling the selectivity can be envisaged from their better hydrogen bond donor (HBD) abilities compared to that of the other organic solvents as well as of water. Due to the better HBD values, the fluorous alcohols efficiently promote the initial bisimine formation by electrophilic activation of the aldehyde carbonyl. Subsequently the hydrogen-bond-mediated activation of the in situ-formed bisimine triggers the rearrangement via 1,3-hydride shift to form the 1,2-disubstituted benzimidazoles.

Using formative research to develop CHANGE!: a curriculum-based physical activity promoting intervention

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Knowles Zoe R

2011-10-01

Full Text Available Abstract Background Low childhood physical activity levels are currently one of the most pressing public health concerns. Numerous school-based physical activity interventions have been conducted with varied success. Identifying effective child-based physical activity interventions are warranted. The purpose of this formative study was to elicit subjective views of children, their parents, and teachers about physical activity to inform the design of the CHANGE! (Children's Health, Activity, and Nutrition: Get Educated! intervention programme. Methods Semi-structured mixed-gender interviews (group and individual were conducted in 11 primary schools, stratified by socioeconomic status, with 60 children aged 9-10 years (24 boys, 36 girls, 33 parents (4 male, 29 female and 10 teachers (4 male, 6 female. Questions for interviews were structured around the PRECEDE stage of the PRECEDE-PROCEDE model and addressed knowledge, attitudes and beliefs towards physical activity, as well as views on barriers to participation. All data were transcribed verbatim. Pen profiles were constructed from the transcripts in a deductive manner using the Youth Physical Activity Promotion Model framework. The profiles represented analysis outcomes via a diagram of key emergent themes. Results Analyses revealed an understanding of the relationship between physical activity and health, although some children had limited understanding of what constitutes physical activity. Views elicited by children and parents were generally consistent. Fun, enjoyment and social support were important predictors of physical activity participation, though several barriers such as lack of parental support were identified across all group interviews. The perception of family invested time was positively linked to physical activity engagement. Conclusions Families have a powerful and important role in promoting health-enhancing behaviours. Involvement of parents and the whole family is a

Intact fetal ovarian cord formation promotes mouse oocyte survival and development

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Pera Renee

2010-01-01

Full Text Available Abstract Background Female reproductive potential, or the ability to propagate life, is limited in mammals with the majority of oocytes lost before birth. In mice, surviving perinatal oocytes are enclosed in ovarian follicles for subsequent oocyte development and function in the adult. Before birth, fetal germ cells of both sexes develop in clusters, or germline cysts, in the undifferentiated gonad. Upon sex determination of the fetal gonad, germ cell cysts become organized into testicular or ovarian cord-like structures and begin to interact with gonadal somatic cells. Although germline cysts and testicular cords are required for spermatogenesis, the role of cyst and ovarian cord formation in mammalian oocyte development and female fertility has not been determined. Results Here, we examine whether intact fetal ovarian germ and somatic cell cord structures are required for oocyte development using mouse gonad re-aggregation and transplantation to disrupt gonadal organization. We observed that germ cells from disrupted female gonad prior to embryonic day e13.5 completed prophase I of meiosis but did not survive following transplantation. Furthermore, re-aggregated ovaries from e13.5 to e15.5 developed with a reduced number of oocytes. Oocyte loss occurred before follicle formation and was associated with an absence of ovarian cord structure and ovary disorganization. However, disrupted ovaries from e16.5 or later were resistant to the re-aggregation impairment and supported robust oocyte survival and development in follicles. Conclusions Thus, we demonstrate a critical window of oocyte development from e13.5 to e16.5 in the intact fetal mouse ovary, corresponding to the establishment of ovarian cord structure, which promotes oocyte interaction with neighboring ovarian somatic granulosa cells before birth and imparts oocytes with competence to survive and develop in follicles. Because germline cyst and ovarian cord structures are conserved in the

Matrix Metalloproteinases: The Gene Expression Signatures of Head and Neck Cancer Progression

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Iizuka, Shinji [Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037 (United States); Ishimaru, Naozumi; Kudo, Yasusei, E-mail: yasusei@tokushima-u.ac.jp [Department of Oral Molecular Pathology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-8-15 Kuramoto, Tokushima 770-8504 (Japan)

2014-02-13

Extracellular matrix degradation by matrix metalloproteinases (MMPs) plays a pivotal role in cancer progression by promoting motility, invasion and angiogenesis. Studies have shown that MMP expression is increased in head and neck squamous cell carcinomas (HNSCCs), one of the most common cancers in the world, and contributes to poor outcome. In this review, we examine the expression pattern of MMPs in HNSCC by microarray datasets and summarize the current knowledge of MMPs, specifically MMP-1, -3, -7 -10, -12, -13, 14 and -19, that are highly expressed in HNSCCs and involved cancer invasion and angiogenesis.

Enalapril alters the formation of the collagen matrix in spontaneously hypertensive rats

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Alfredo de Souza Bomfim

2003-07-01

Full Text Available OBJECTIVE: To assess the effect of the inhibition of the angiotensin-converting enzyme on the collagen matrix (CM of the heart of newborn spontaneously hypertensive rats (SHR during embryonic development. METHODS: The study comprised the 2 following groups of SHR (n=5 each: treated group - rats conceived from SHR females treated with enalapril maleate (15 mg. kg-1.day-1 during gestation; and nontreated group - offspring of nontreated females. The newborns were euthanized within the first 24 hours after birth and their hearts were removed and processed for histological study. Three fields per animal were considered for computer-assisted digital analysis and determination of the volume densities (Vv of the nuclei and CM. The images were segmented with the aid of Image Pro Plus® 4.5.029 software (Media Cybernetics. RESULTS: No difference was observed between the treated and nontreated groups in regard to body mass, cardiac mass, and the relation between cardiac and body mass. A significant reduction in the Vv[matrix] and a concomitant increase in the Vv[nuclei] were observed in the treated group as compared with those in the nontreated group. CONCLUSION: The treatment with enalapril of hypertensive rats during pregnancy alters the collagen content and structure of the myocardium of newborns.

Experiences of interprofessional implementation of a healthcare matrix.

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Lee, Su-Shin; Chiang, Hung-Che; Chen, Meng-Chum; Chen, Ling-Sui; Hsu, Pei-Ling; Sun, I-Feng; Lai, Chung-Sheng

2008-12-01

The Taiwan Joint Commission on Hospital Accreditation endorsed the Institute of Medicine (IOM) dimensions of health care quality as safe, timely, effective, efficient, equitable, and patient-centered. The Taiwan Association of Medical Education has also adopted the Accreditation Council for Graduate Medical Education (ACGME) outcome project and core competencies for Taiwan physicians in training. These schemes focus on patient care, medical knowledge and skills, interpersonal and communication skills, professionalism, system-based practice and practice-based learning and improvement. Bingham (2004) described a Healthcare Matrix that links to the ACGME Core Competencies and the IOM Dimensions of Quality as a tool to improve health care. The matrix provides a blueprint to help residents learn the core competencies in patient care, and to help the faculty to link mastery of the competencies with improvements in quality of care. However, the "six-by-six" framework was too complicated to fill in. Furthermore, the translation of the IOM aims and ACGME core competencies into the Chinese language seemed incoherent and difficult to remember. We simplified the matrix by merging some columns of the original Healthcare Matrix, and reduced the 6 x 6 form into a 4 x 5 framework. The matrix was applied in case conferences, mortality and morbidity conferences, combined meetings and nursing quality assurance meetings in different departments. This format organizes the presentation and discussion, highlighting strengths or deficiencies in key aspects of patient care. With interprofessional collaboration, the matrix has been used in the departments of Plastic Surgery, and Nursing and Performance Management in our hospital. The achievements are encouraging. The Taiwan Edition Healthcare Matrix is worthy of consideration, having been used in a Mandarin-speaking region of Asia.

Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

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Chen, Yan; Lu, Xiaoling; Guo, Luo; Ni, Wenli; Zhang, Yanping; Zhao, Liping; Wu, Lingjie; Sun, Shan; Zhang, Shasha; Tang, Mingliang; Li, Wenyan; Chai, Renjie; Li, Huawei

2017-01-01

Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway. PMID:29311816

Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

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Yan Chen

2017-12-01

Full Text Available Hair cell (HC loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.

Advance on Al2O3 Particulates Reinforced Aluminum Metal Matrix Composites (Al-MMCs Manufactured by the Power Metallurgy(PM Methods- Improved PM Techniques

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Xu Lina

2016-01-01

Full Text Available Aluminum metal matrix composites (Al-MMCs with Al2O3 particulates as reinforcement fabricated by the power metallurgy (PM methods have gained much attention due to their unique characteristics of the wide range of Al2O3 particles addition, easy-operating process and effectiveness. The improved PM techniques, such as the high energy ball milling, powder extruder and high pressure torsion were applied to further strengthening the properties or/and diminishing the agglomeration of strength particles. The formation of liquid phase assisted densification of compacts to promote the sintering of composites. Complex design of Al2O3 particles with other particles was another efficient method to tailor the properties of Al-MMCs.

Matrix Production, Pigment Synthesis, and Sporulation in a Marine Isolated Strain of Bacillus pumilus.

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Di Luccia, Blanda; Riccio, Antonio; Vanacore, Adele; Baccigalupi, Loredana; Molinaro, Antonio; Ricca, Ezio

2015-10-21

The ability to produce an extracellular matrix and form multicellular communities is an adaptive behavior shared by many bacteria. In Bacillus subtilis, the model system for spore-forming bacteria, matrix production is one of the possible differentiation pathways that a cell can follow when vegetative growth is no longer feasible. While in B. subtilis the genetic system controlling matrix production has been studied in detail, it is still unclear whether other spore formers utilize similar mechanisms. We report that SF214, a pigmented strain of Bacillus pumilus isolated from the marine environment, can produce an extracellular matrix relying on orthologs of many of the genes known to be important for matrix synthesis in B. subtilis. We also report a characterization of the carbohydrates forming the extracellular matrix of strain SF214. The isolation and characterization of mutants altered in matrix synthesis, pigmentation, and spore formation suggest that in strain SF214 the three processes are strictly interconnected and regulated by a common molecular mechanism.

Photon-induced formation of CdS nanocrystals in selected areas of polymer matrices

International Nuclear Information System (INIS)

Athanassiou, Athanassia; Cingolani, Roberto; Tsiranidou, Elsa; Fotakis, Costas; Laera, Anna Maria; Piscopiello, Emanuela; Tapfer, Leander

2007-01-01

We demonstrate light-induced formation of semiconductor quantum dots in TOPAS registered polymer matrix with very high control of their size and their spatial localization. Irradiation with UV laser pulses of polymer films embedding Cd thiolate precursors results in the formation of cadmium sulfide nanocrystals well confined in the irradiation area, through a macroscopically nondestructive procedure for the host matrix. With increasing number of laser pulses, we accomplish the formation of nanoparticles with gradually increasing dimensions, resulting in the dynamic change of the spectra emitted by the formed nanocomposite areas. The findings are supported by x-ray diffraction and transmission electron microscopy measurements

Improved Spectra for MALDI MSI of Peptides Using Ammonium Phosphate Monobasic in MALDI Matrix.

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Ucal, Yasemin; Ozpinar, Aysel

2018-05-10

MALDI mass spectrometry imaging (MSI) enables analysis of peptides along with histology. However, there are several critical steps in MALDI MSI of peptides, one of which is spectral quality. Suppression of MALDI matrix clusters by the aid of ammonium salts in MALDI experiments is well-known. It is asserted that addition of ammonium salts dissociates potential matrix adducts and thereafter decreases matrix cluster formation. Consequently, MALDI MS sensitivity and mass accuracy increases. Up to our knowledge, a limited number of MALDI MSI studies used ammonium salts as matrix additives to suppress matrix clusters and enhance peptide signals. In this work, we investigated the effect of ammonium phosphate monobasic (AmP) as alpha-cyano-4-hydroxycinnamic acid (α-CHCA) matrix additive in MALDI MSI of peptides. Prior to MALDI MSI, the effect of varying concentrations of AmP in α-CHCA were assessed in bovine serum albumin (BSA) tryptic digests and compared with the control (α-CHCA without AmP). Based on our data, the addition of AmP as matrix additive decreased matrix cluster formation regardless of its concentration and, specifically 8 mM AmP and 10 mM AmP increased BSA peptide signal intensities. In MALDI MSI of peptides, both 8 mM, and 10 mM AmP in α-CHCA improved peptide signals especially in the mass range of m/z 2000 to 3000. In particular, 9 peptide signals were found to have differential intensities within the tissues deposited with AmP in α-CHCA (AUC>0.60). To the best of our knowledge, this is the first MALDI MSI of peptides work investigating different concentrations of AmP as α-CHCA matrix additive in order to enhance peptide signals in formalin fixed paraffin embedded (FFPE) tissues. Further, AmP as part of α-CHCA matrix could enhance protein identifications and support MALDI MSI based proteomic approaches. This article is protected by copyright. All rights reserved.

Periostin is an extracellular matrix protein required for eruption of incisors in mice

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Kii, Isao; Amizuka, Norio; Minqi, Li; Kitajima, Satoshi; Saga, Yumiko; Kudo, Akira

2006-01-01

A characteristic tooth of rodents, the incisor continuously grows throughout life by the constant formation of dentin and enamel. Continuous eruption of the incisor is accompanied with formation of shear zone, in which the periodontal ligament is remodeled. Although the shear zone plays a role in the remodeling, its molecular biological aspect is barely understood. Here, we show that periostin is essential for formation of the shear zone. Periostin -/- mice showed an eruption disturbance of incisors. Histological observation revealed that deletion of periostin led to disappearance of the shear zone. Electron microscopy revealed that the disappearance of the shear zone resulted from a failure in digestion of collagen fibers in the periostin -/- mice. Furthermore, immunohistochemical analysis using anti-periostin antibodies demonstrated the restricted localization of periostin protein in the shear zone. Periostin is an extracellular matrix protein, and immunoelectron microscopy showed a close association of periostin with collagen fibrils in vivo. These results suggest that periostin functions in the remodeling of collagen matrix in the shear zone

Impact of matrix stiffness on fibroblast function

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El-Mohri, Hichem; Wu, Yang; Mohanty, Swetaparna; Ghosh, Gargi, E-mail: gargi@umich.edu

2017-05-01

Chronic non-healing wounds, caused by impaired production of growth factors and reduced vascularization, represent a significant burden to patients, health care professionals, and health care system. While several wound dressing biomaterials have been developed, the impact of the mechanical properties of the dressings on the residing cells and consequently on the healing of the wounds is largely overlooked. The primary focus of this study is to explore whether manipulation of the substrate mechanics can regulate the function of fibroblasts, particularly in the context of their angiogenic activity. A photocrosslinkable hydrogel platform with orthogonal control over gel modulus and cell adhesive sites was developed to explore the quantitative relationship between ECM compliance and fibroblast function. Increase in matrix stiffness resulted in enhanced fibroblast proliferation and stress fiber formation. However, the angiogenic activity of fibroblasts was found to be optimum when the cells were seeded on compliant matrices. Thus, the observations suggest that the stiffness of the wound dressing material may play an important role in the progression of wound healing. - Highlights: • Proliferation and stress fiber formation of fibroblasts increase with increasing matrix mechanics. • Cell area correlates with the growth of fibroblasts. • Angiogenic activity of fibroblasts optimum when cells seeded on compliant gels.

Extracellular matrix components and culture regimen selectively regulate cartilage formation by self-assembling human mesenchymal stem cells in vitro and in vivo.

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Ng, Johnathan; Wei, Yiyong; Zhou, Bin; Burapachaisri, Aonnicha; Guo, Edward; Vunjak-Novakovic, Gordana

2016-12-09

Cartilage formation from self-assembling mesenchymal stem cells (MSCs) in vitro recapitulate important cellular events during mesenchymal condensation that precedes native cartilage development. The goal of this study was to investigate the effects of cartilaginous extracellular matrix (ECM) components and culture regimen on cartilage formation by self-assembling human MSCs in vitro and in vivo. Human bone marrow-derived MSCs (hMSCs) were seeded and compacted in 6.5-mm-diameter transwell inserts with coated (type I, type II collagen) or uncoated (vehicle) membranes, at different densities (0.5 × 10 6 , 1.0 × 10 6 , 1.5 × 10 6 per insert). Pellets were formed by aggregating hMSCs (0.25 × 10 6 ) in round-bottomed wells. All tissues were cultured for up to 6 weeks for in vitro analyses. Discs (cultured for 6, 8 or 10 weeks) and pellets (cultured for 10 weeks) were implanted subcutaneously in immunocompromised mice to evaluate the cartilage stability in vivo. Type I and type II collagen coatings enabled cartilage disc formation from self-assembling hMSCs. Without ECM coating, hMSCs formed dome-shaped tissues resembling the pellets. Type I collagen, expressed in the prechondrogenic mesenchyme, improved early chondrogenesis versus type II collagen. High seeding density improved cartilage tissue properties but resulted in a lower yield of disc formation. Discs and pellets exhibited compositional and organizational differences in vitro and in vivo. Prolonged chondrogenic induction of the discs in vitro expedited endochondral ossification in vivo. The outcomes of cartilage tissues formed from self-assembling MSCs in vitro and in vivo can be modulated by the control of culture parameters. These insights could motivate new directions for engineering cartilage and bone via a cartilage template from self-assembling MSCs.

Characterisation of cell cycle arrest and terminal differentiation in a maximally proliferative human epithelial tissue: Lessons from the human hair follicle matrix.

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Purba, Talveen S; Brunken, Lars; Peake, Michael; Shahmalak, Asim; Chaves, Asuncion; Poblet, Enrique; Ceballos, Laura; Gandarillas, Alberto; Paus, Ralf

2017-09-01

Human hair follicle (HF) growth and hair shaft formation require terminal differentiation-associated cell cycle arrest of highly proliferative matrix keratinocytes. However, the regulation of this complex event remains unknown. CIP/KIP family member proteins (p21 CIP1 , p27 KIP1 and p57 KIP2 ) regulate cell cycle progression/arrest, endoreplication, differentiation and apoptosis. Since they have not yet been adequately characterized in the human HF, we asked whether and where CIP/KIP proteins localise in the human hair matrix and pre-cortex in relation to cell cycle activity and HF-specific epithelial cell differentiation that is marked by keratin 85 (K85) protein expression. K85 expression coincided with loss or reduction in cell cycle activity markers, including in situ DNA synthesis (EdU incorporation), Ki-67, phospho-histone H3 and cyclins A and B1, affirming a post-mitotic state of pre-cortical HF keratinocytes. Expression of CIP/KIP proteins was found abundantly within the proliferative hair matrix, concomitant with a role in cell cycle checkpoint control. p21 CIP1 , p27 KIP1 and cyclin E persisted within post-mitotic keratinocytes of the pre-cortex, whereas p57 KIP2 protein decreased but became nuclear. These data imply a supportive role for CIP/KIP proteins in maintaining proliferative arrest, differentiation and anti-apoptotic pathways, promoting continuous hair bulb growth and hair shaft formation in anagen VI. Moreover, post-mitotic hair matrix regions contained cells with enlarged nuclei, and DNA in situ hybridisation showed cells that were >2N in the pre-cortex. This suggests that CIP/KIP proteins might counterbalance cyclin E to control further rounds of DNA replication in a cell population that has a propensity to become tetraploid. These data shed new light on the in situ-biography of human hair matrix keratinocytes on their path of active cell cycling, arrest and terminal differentiation, and showcase the human HF as an excellent, clinically

Proteomic analysis of the organic matrix of the abalone Haliotis asinina calcified shell

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Degnan Bernard M

2010-11-01

Full Text Available Abstract Background The formation of the molluscan shell is regulated to a large extent by a matrix of extracellular macromolecules that are secreted by the shell forming tissue, the mantle. This so called "calcifying matrix" is a complex mixture of proteins and glycoproteins that is assembled and occluded within the mineral phase during the calcification process. While the importance of the calcifying matrix to shell formation has long been appreciated, most of its protein components remain uncharacterised. Results Recent expressed sequence tag (EST investigations of the mantle tissue from the tropical abalone (Haliotis asinina provide an opportunity to further characterise the proteins in the shell by a proteomic approach. In this study, we have identified a total of 14 proteins from distinct calcified layers of the shell. Only two of these proteins have been previously characterised from abalone shells. Among the novel proteins are several glutamine- and methionine-rich motifs and hydrophobic glycine-, alanine- and acidic aspartate-rich domains. In addition, two of the new proteins contained Kunitz-like and WAP (whey acidic protein protease inhibitor domains. Conclusion This is one of the first comprehensive proteomic study of a molluscan shell, and should provide a platform for further characterization of matrix protein functions and interactions.

Biomineralization of a Self-assembled, Soft-Matrix Precursor: Enamel

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Snead, Malcolm L.

2015-04-01

Enamel is the bioceramic covering of teeth, a composite tissue composed of hierarchical organized hydroxyapatite crystallites fabricated by cells under physiologic pH and temperature. Enamel material properties resist wear and fracture to serve a lifetime of chewing. Understanding the cellular and molecular mechanisms for enamel formation may allow a biology-inspired approach to material fabrication based on self-assembling proteins that control form and function. A genetic understanding of human diseases exposes insight from nature's errors by exposing critical fabrication events that can be validated experimentally and duplicated in mice using genetic engineering to phenocopy the human disease so that it can be explored in detail. This approach led to an assessment of amelogenin protein self-assembly that, when altered, disrupts fabrication of the soft enamel protein matrix. A misassembled protein matrix precursor results in loss of cell-to-matrix contacts essential to fabrication and mineralization.

Matrix metalloproteinases in the brain and blood–brain barrier: Versatile breakers and makers

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Rempe, Ralf G; Hartz, Anika MS

2016-01-01

Matrix metalloproteinases are versatile endopeptidases with many different functions in the body in health and disease. In the brain, matrix metalloproteinases are critical for tissue formation, neuronal network remodeling, and blood–brain barrier integrity. Many reviews have been published on matrix metalloproteinases before, most of which focus on the two best studied matrix metalloproteinases, the gelatinases MMP-2 and MMP-9, and their role in one or two diseases. In this review, we provide a broad overview of the role various matrix metalloproteinases play in brain disorders. We summarize and review current knowledge and understanding of matrix metalloproteinases in the brain and at the blood–brain barrier in neuroinflammation, multiple sclerosis, cerebral aneurysms, stroke, epilepsy, Alzheimer’s disease, Parkinson’s disease, and brain cancer. We discuss the detrimental effects matrix metalloproteinases can have in these conditions, contributing to blood–brain barrier leakage, neuroinflammation, neurotoxicity, demyelination, tumor angiogenesis, and cancer metastasis. We also discuss the beneficial role matrix metalloproteinases can play in neuroprotection and anti-inflammation. Finally, we address matrix metalloproteinases as potential therapeutic targets. Together, in this comprehensive review, we summarize current understanding and knowledge of matrix metalloproteinases in the brain and at the blood–brain barrier in brain disorders. PMID:27323783

SPARC regulates extracellular matrix organization through its modulation of integrin-linked kinase activity.

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Barker, Thomas H; Baneyx, Gretchen; Cardó-Vila, Marina; Workman, Gail A; Weaver, Matt; Menon, Priya M; Dedhar, Shoukat; Rempel, Sandra A; Arap, Wadih; Pasqualini, Renata; Vogel, Viola; Sage, E Helene

2005-10-28

SPARC, a 32-kDa matricellular glycoprotein, mediates interactions between cells and their extracellular matrix, and targeted deletion of Sparc results in compromised extracellular matrix in mice. Fibronectin matrix provides provisional tissue scaffolding during development and wound healing and is essential for the stabilization of mature extracellular matrix. Herein, we report that SPARC expression does not significantly affect fibronectin-induced cell spreading but enhances fibronectin-induced stress fiber formation and cell-mediated partial unfolding of fibronectin molecules, an essential process in fibronectin matrix assembly. By phage display, we identify integrin-linked kinase as a potential binding partner of SPARC and verify the interaction by co-immunoprecipitation and colocalization in vitro. Cells lacking SPARC exhibit diminished fibronectin-induced integrin-linked kinase activation and integrin-linked kinase-dependent cell-contractile signaling. Furthermore, induced expression of SPARC in SPARC-null fibroblasts restores fibronectin-induced integrin-linked kinase activation, downstream signaling, and fibronectin unfolding. These data further confirm the function of SPARC in extracellular matrix organization and identify a novel mechanism by which SPARC regulates extracellular matrix assembly.

Regulation of the human ADAMTS-4 promoter by transcription factors and cytokines

International Nuclear Information System (INIS)

Thirunavukkarasu, Kannan; Pei, Yong; Moore, Terry L.; Wang, He; Yu, Xiao-peng; Geiser, Andrew G.; Chandrasekhar, Srinivasan

2006-01-01

ADAMTS-4 (aggrecanase-1) is a metalloprotease that plays a role in aggrecan degradation in the cartilage extracellular matrix. In order to understand the regulation of ADAMTS-4 gene expression we have cloned and characterized a functional 4.5 kb human ADAMTS-4 promoter. Sequence analysis of the promoter revealed the presence of putative binding sites for nuclear factor of activated T cells (NFAT) and Runx family of transcription factors that are known to regulate chondrocyte maturation and differentiation. Using promoter-reporter assays and mRNA analysis we have analyzed the role of chondrocyte-expressed transcription factors NFATp and Runx2 and have shown that ADAMTS-4 is a potential downstream target of these two factors. Our results suggest that inhibition of the expression/function of NFATp and/or Runx2 may enable us to modulate aggrecan degradation in normal physiology and/or in degenerative joint diseases. The ADAMTS-4 promoter would serve as a valuable mechanistic tool to better understand the regulation of ADAMTS-4 expression by signaling pathways that modulate cartilage matrix breakdown

Molecular events in matrix protein metabolism in the aging kidney

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Sataranatarajan, Kavithalakshmi; Feliers, Denis; Mariappan, Meenalakshmi M.; Lee, Hak Joo; Lee, Myung Ja; Day, Robert T.; Yalamanchili, Hima Bindu; Choudhury, Goutam G.; Barnes, Jeffrey L.; Van Remmen, Holly; Richardson, Arlan; Kasinath, Balakuntalam S.

2018-01-01

Summary We explored molecular events associated with aging-induced matrix changes in the kidney. C57BL6 mice were studied in youth, middle age, and old age. Albuminuria and serum cystatin C level (an index of glomerular filtration) increased with aging. Renal hypertrophy was evident in middle-aged and old mice and was associated with glomerulomegaly and increase in mesangial fraction occupied by extracellular matrix. Content of collagen types I and III and fibronectin was increased with aging; increment in their mRNA varied with the phase of aging. The content of ZEB1 and ZEB2, collagen type I transcription inhibitors, and their binding to the collagen type Iα2 promoter by ChIP assay also showed age-phase-specific changes. Lack of increase in mRNA and data from polysome assay suggested decreased degradation as a potential mechanism for kidney collagen type I accumulation in the middle-aged mice. These changes occurred with increment in TGFβ mRNA and protein and activation of its SMAD3 pathway; SMAD3 binding to the collagen type Iα2 promoter was also increased. TGFβ-regulated microRNAs (miRs) exhibited selective regulation. The renal cortical content of miR-21 and miR-200c, but not miR-192, miR-200a, or miR-200b, was increased with aging. Increased miR-21 and miR-200c contents were associated with reduced expression of their targets, Sprouty-1 and ZEB2, respectively. These data show that aging is associated with complex molecular events in the kidney that are already evident in the middle age and progress to old age. Agephase-specific regulation of matrix protein synthesis occurs and involves matrix protein-specific transcriptional and post-transcriptional mechanisms. PMID:23020145

The C. elegans DSB-2 protein reveals a regulatory network that controls competence for meiotic DSB formation and promotes crossover assurance.

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Simona Rosu

Full Text Available For most organisms, chromosome segregation during meiosis relies on deliberate induction of DNA double-strand breaks (DSBs and repair of a subset of these DSBs as inter-homolog crossovers (COs. However, timing and levels of DSB formation must be tightly controlled to avoid jeopardizing genome integrity. Here we identify the DSB-2 protein, which is required for efficient DSB formation during C. elegans meiosis but is dispensable for later steps of meiotic recombination. DSB-2 localizes to chromatin during the time of DSB formation, and its disappearance coincides with a decline in RAD-51 foci marking early recombination intermediates and precedes appearance of COSA-1 foci marking CO-designated sites. These and other data suggest that DSB-2 and its paralog DSB-1 promote competence for DSB formation. Further, immunofluorescence analyses of wild-type gonads and various meiotic mutants reveal that association of DSB-2 with chromatin is coordinated with multiple distinct aspects of the meiotic program, including the phosphorylation state of nuclear envelope protein SUN-1 and dependence on RAD-50 to load the RAD-51 recombinase at DSB sites. Moreover, association of DSB-2 with chromatin is prolonged in mutants impaired for either DSB formation or formation of downstream CO intermediates. These and other data suggest that association of DSB-2 with chromatin is an indicator of competence for DSB formation, and that cells respond to a deficit of CO-competent recombination intermediates by prolonging the DSB-competent state. In the context of this model, we propose that formation of sufficient CO-competent intermediates engages a negative feedback response that leads to cessation of DSB formation as part of a major coordinated transition in meiotic prophase progression. The proposed negative feedback regulation of DSB formation simultaneously (1 ensures that sufficient DSBs are made to guarantee CO formation and (2 prevents excessive DSB levels that could

Nanophosphor composite scintillators comprising a polymer matrix

Science.gov (United States)

Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

2010-11-16

An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

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Singh, Mrityunjay; Morscher, Gregory N.

2004-01-01

Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, and nuclear industries. Potential composite applications differ in their requirements for thickness. For example, many space applications such as "nozzle ramps" or "heat exchangers" require very thin (structures whereas turbine blades would require very thick parts (> or = 1 cm). Little is known about the effect of thickness on stress-strain behavior or the elevated temperature tensile properties controlled by oxidation diffusion. In this study, composites consisting of woven Hi-Nicalon (trademark) fibers a carbon interphase and CVI SiC matrix were fabricated with different numbers of plies and thicknesses. The effect of thickness on matrix crack formation, matrix crack growth and diffusion kinetics will be discussed. In another approach, hybrid fiber-lay up concepts have been utilized to "alloy" desirable properties of different fiber types for mechanical properties, thermal stress management, and oxidation resistance. Such an approach has potential for the C(sub I)-SiC and SiC(sub f)-SiC composite systems. CVI SiC matrix composites with different stacking sequences of woven C fiber (T300) layers and woven SiC fiber (Hi-Nicalon (trademark)) layers were fabricated. The results will be compared to standard C fiber reinforced CVI SiC matrix and Hi-Nicalon reinforced CVI SiC matrix composites. In addition, shear properties of these composites at different temperatures will also be presented. Other design and implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

Wormholes propagation for fractured-vuggy formation: Laboratory tests, numerical simulation and field application

Directory of Open Access Journals (Sweden)

Fei Liu

2017-12-01

Full Text Available The propagation of wormhole is vital important for matrix acidizing and acid fracturing in carbonate reservoirs. While the formation of acid dissolved wormhole is derived from heterogeneous physical and chemical transportations and reactions. Alveolate dissolved pores, krast caves, and natural fissures are the major reservoir spaces for the Sinian dolomite formation in the Anyue gas field of the Sichuan Basin. There were four categories of formation, which are matrix dominated, inter-breccia dissolved pore dominated, dissolved pore and cave dominated, and fissure and cave dominated, based on the development intensity and connectedness of caves and fissures. The caves and fissures make the wormhole formation and propagation particularly complicated. Firstly, the 3-D topological structure of dissolved pores, vugs, fissures and throats inside cores is quantitatively scanned by CT imaging technology for its feature of vivid and damage-free. Secondly, 3-D patterns of wormhole are obtained with CT scanning after core flooding by acid. Additionally, the pore-throat network model is reconstructed with digital cores technology. Then, the size and ratio of pore and throat before and after core flooding by acid is analyzed and the absolute permeability of pore scale flow is numerically simulated to understand the fundamental influence of pores and vugs distribution and connectedness on wormhole propagation. Lastly, the wormhole pattern gained by CT scanning and simulating with two-scale model is compared. Meanwhile, the corrected two-scale model is utilized to simulate the wormhole propagation for matrix acidizing and acid fracturing of Sinian fractured-vuggy dolomite in Anyue gas field, Sichuan Basin. The optimized injection rate and volume were in agreement with the characteristic matrix acidizing operating curve, which indicates that the two-scale model was suitable for matrix acidizing optimization design of such formations. In addition, the simulated

Transcriptional Inhibition of Matrix Metal loproteinase 9 (MMP-9 Activity by a c-fos/Estrogen Receptor Fusion Protein is Mediated by the Proximal AP-1 Site of the MMP-9 Promoter and Correlates with Reduced Tumor Cell Invasion

Directory of Open Access Journals (Sweden)

David L. Crowe

1999-10-01

Full Text Available Tumor cell invasion of basement membranes is one of the hallmarks of malignant transformation. Tumor cells secrete proteolytic enzymes known as matrix metalloproteinases (MMPs which degrade extracellular matrix molecules. Increased expression of MMP-9 has been associated with acquisition of invasive phenotype in many tumors. However, multiple mechanisms for regulation of MMP-9 gene expression by tumor cell lines have been proposed. A number of transcription factor binding sites have been characterized in the upstream regulatory region of the MMP-9 gene, including those for AP-1. To determine how a specific AP-1 family member, c-fos, regulates MMP-9 promoter activity through these sites, we used an expression vector containing the c-fos coding region fused to the estrogen receptor (ER ligand binding domain. This construct is activated upon binding estradiol. Stable expression of this construct in ER negative squamous cell carcinoma (SCC lines produced an estradiol dependent decrease in the number of cells that migrated through a reconstituted basement membrane. This decreased invasiveness was accompanied by estradiol dependent downregulation of MMP-9 activity as determined by gelatin zymography. Estradiol also produced transcriptional downregulation of an MMP-9 promoter construct in cells transiently transfected with the c-fosER expression vector. This downregulation was mediated by the AP-1 site at —79 by in the MMP-9 promoter. We concluded that the proximal AP-1 site mediated the transcriptional downregulation of the MMP-9 promoter by a conditionally activated c-fos fusion protein.

Experimental Investigation of Effect on Hydrate Formation in Spray Reactor

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Jianzhong Zhao

2015-01-01

Full Text Available The effects of reaction condition on hydrate formation were conducted in spray reactor. The temperature, pressure, and gas volume of reaction on hydrate formation were measured in pure water and SDS solutions at different temperature and pressure with a high-pressure experimental rig for hydrate formation. The experimental data and result reveal that additives could improve the hydrate formation rate and gas storage capacity. Temperature and pressure can restrict the hydrate formation. Lower temperature and higher pressure can promote hydrate formation, but they can increase production cost. So these factors should be considered synthetically. The investigation will promote the advance of gas storage technology in hydrates.

Spermine oxidase promotes bile canalicular lumen formation through acrolein production.

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Uemura, Takeshi; Takasaka, Tomokazu; Igarashi, Kazuei; Ikegaya, Hiroshi

2017-11-01

Spermine oxidase (SMOX) catalyzes oxidation of spermine to generate spermidine, hydrogen peroxide (H 2 O 2 ) and 3-aminopropanal, which is spontaneously converted to acrolein. SMOX is induced by a variety of stimuli including bacterial infection, polyamine analogues and acetaldehyde exposure. However, the physiological functions of SMOX are not yet fully understood. We investigated the physiological role of SMOX in liver cells using human hepatocellular carcinoma cell line HepG2. SMOX localized to the bile canalicular lumen, as determined by F-actin staining. Knockdown of SMOX reduced the formation of bile canalicular lumen. We also found that phospho-Akt (phosphorylated protein kinase B) was localized to canalicular lumen. Treatment with Akt inhibitor significantly reduced the formation of bile canalicular lumen. Acrolein scavenger also inhibited the formation of bile canalicular lumen. PTEN, phosphatase and tensin homolog and an inhibitor of Akt, was alkylated in a SMOX-dependent manner. Our results suggest that SMOX plays a central role in the formation of bile canalicular lumen in liver cells by activating Akt pathway through acrolein production.

Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

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Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.

2016-07-01

Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

Experiences of Interprofessional Implementation of a Healthcare Matrix

Directory of Open Access Journals (Sweden)

Su-Shin Lee

2008-12-01

Full Text Available The Taiwan Joint Commission on Hospital Accreditation endorsed the Institute of Medicine (IOM dimensions of health care quality as safe, timely, effective, efficient, equitable, and patient-centered. The Taiwan Association of Medical Education has also adopted the Accreditation Council for Graduate Medical Education (ACGME outcome project and core competencies for Taiwan physicians in training. These schemes focus on patient care, medical knowledge and skills, interpersonal and communication skills, professionalism, system-based practice and practice-based learning and improvement. Bingham (2004 described a Healthcare Matrix that links to the ACGME Core Competencies and the IOM Dimensions of Quality as a tool to improve health care. The matrix provides a blueprint to help residents learn the core competencies in patient care, and to help the faculty to link mastery of the competencies with improvements in quality of care. However, the “six-by-six” framework was too complicated to fill in. Furthermore, the translation of the IOM aims and ACGME core competencies into the Chinese language seemed incoherent and difficult to remember. We simplified the matrix by merging some columns of the original Healthcare Matrix, and reduced the 6 × 6 form into a 4 × 5 framework. The matrix was applied in case conferences, mortality and morbidity conferences, combined meetings and nursing quality assurance meetings in different departments. This format organizes the presentation and discussion, highlighting strengths or deficiencies in key aspects of patient care. With interprofessional collaboration, the matrix has been used in the departments of Plastic Surgery, and Nursing and Performance Management in our hospital. The achievements are encouraging. The Taiwan Edition Healthcare Matrix is worthy of consideration, having been used in a Mandarin-speaking region of Asia.

Compilation and R-matrix analysis of Big Bang nuclear reaction rates

International Nuclear Information System (INIS)

Descouvemont, Pierre; Adahchour, Abderrahim; Angulo, Carmen; Coc, Alain; Vangioni-Flam, Elisabeth

2004-01-01

We use the R-matrix theory to fit low-energy data on nuclear reactions involved in Big Bang nucleosynthesis. Special attention is paid to the rate uncertainties which are evaluated on statistical grounds. We provide S factors and reaction rates in tabular and graphical formats

Overhydroxylation of Lysine of Collagen Increases Uterine Fibroids Proliferation: Roles of Lysyl Hydroxylases, Lysyl Oxidases, and Matrix Metalloproteinases

Directory of Open Access Journals (Sweden)

Marwa Kamel

2017-01-01

Full Text Available The role of the extracellular matrix (ECM in uterine fibroids (UF has recently been appreciated. Overhydroxylation of lysine residues and the subsequent formation of hydroxylysylpyridinoline (HP and lysylpyridinoline (LP cross-links underlie the ECM stiffness and profoundly affect tumor progression. The aim of the current study was to investigate the relationship between ECM of UF, collagen and collagen cross-linking enzymes [lysyl hydroxylases (LH and lysyl oxidases (LOX], and the development and progression of UF. Our results indicated that hydroxyl lysine (Hyl and HP cross-links are significantly higher in UF compared to the normal myometrial tissues accompanied by increased expression of LH (LH2b and LOX. Also, increased resistance to matrix metalloproteinases (MMP proteolytic degradation activity was observed. Furthermore, the extent of collagen cross-links was positively correlated with the expression of myofibroblast marker (α-SMA, growth-promoting markers (PCNA; pERK1/2; FAKpY397; Ki-67; and Cyclin D1, and the size of UF. In conclusion, our study defines the role of overhydroxylation of collagen and collagen cross-linking enzymes in modulating UF cell proliferation, differentiation, and resistance to MMP. These effects can establish microenvironment conducive for UF progression and thus represent potential target treatment options of UF.

Mechanical and corrosion behaviors of developed copper-based metal matrix composites

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Singh, Manvandra Kumar; Gautam, Rakesh Kumar; Prakash, Rajiv; Ji, Gopal

2018-03-01

This work investigates mechanical properties and corrosion resistances of cast copper-tungsten carbide (WC) metal matrix composites (MMCs). Copper matrix composites have been developed by stir casting technique. Different sizes of micro and nano particles of WC particles are utilized as reinforcement to prepare two copper-based composites, however, nano size of WC particles are prepared by high-energy ball milling. XRD (X-rays diffraction) characterize the materials for involvement of different phases. The mechanical behavior of composites has been studied by Vickers hardness test and compression test; while the corrosion behavior of developed composites is investigated by electrochemical impedance spectroscopy in 0.5 M H2SO4 solutions. The results show that hardness, compressive strength and corrosion resistance of copper matrix composites are very high in comparison to that of copper matrix, which attributed to the microstructural changes occurred during composite formation. SEM (Scanning electron microscopy) reveals the morphology of the corroded surfaces.

Poly-MVA attenuates 7,12- dimethylbenz[a]anthracene initiated and croton oil promoted skin papilloma formation on mice skin.

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Veena, Ravindran K; Ajith, Thekkuttuparambil A; Janardhanan, Kainoor K; Antonawich, Francis

2017-09-01

Chemopreventive agents which exhibit activities such as anti-inflammation, inhibition of carcinogen induced mutagenesis and scavenging of free radical might play a decisive role in the inhibition of chemical carcinogenesis either at the initiation or promotion stage. Many synthesized palladium (Pd) complexes tested experimentally for antitumor activity are found effective. Poly-MVA is a liquid blend preparation containing B complex vitamins, ruthenium with Pd complexed with alpha lipoic acid as the major ingredients. The antitumor effect of Poly-MVA was evaluated against 7,12-dimethylbenz[a] anthracene-initiated croton oil-promoted papilloma formation on mice skin. Skin tumor was initiated with a single application of 390 nmol of DMBA in 20 µl acetone. The effect of Poly-MVA against croton oil- induced inflammation and lipid peroxidation on the mice skin was also evaluated. Topical application of Poly-MVA (100 µl, twice weekly for 18 weeks) 30 minutes prior to each croton oil application, significantly decreased the tumor incidence (11%) and the average number of tumor per animals. Application of Poly-MVA (100 µl) before croton oil significantly (p < 0.05) protected the mouse skin from inflammation (36%) and lipid peroxidation (14%) when compared to the croton oil alone treated group. Experimental results indicate that Poly-MVA attenuate the tumor promoting effects of croton oil and the effect may probably be due to its anti-inflammatory and antioxidant activity.

Mutant IDH1 Promotes Glioma Formation In Vivo

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Beatrice Philip

2018-05-01

Full Text Available Summary: Isocitrate dehydrogenase 1 (IDH1 is the most commonly mutated gene in grade II–III glioma and secondary glioblastoma (GBM. A causal role for IDH1R132H in gliomagenesis has been proposed, but functional validation in vivo has not been demonstrated. In this study, we assessed the role of IDH1R132H in glioma development in the context of clinically relevant cooperating genetic alterations in vitro and in vivo. Immortal astrocytes expressing IDH1R132H exhibited elevated (R-2-hydroxyglutarate levels, reduced NADPH, increased proliferation, and anchorage-independent growth. Although not sufficient on its own, IDH1R132H cooperated with PDGFA and loss of Cdkn2a, Atrx, and Pten to promote glioma development in vivo. These tumors resembled proneural human mutant IDH1 GBM genetically, histologically, and functionally. Our findings support the hypothesis that IDH1R132H promotes glioma development. This model enhances our understanding of the biology of IDH1R132H-driven gliomas and facilitates testing of therapeutic strategies designed to combat this deadly disease. : Philip et al. show that mutant IDH1 cooperates with PDGFA and loss of Cdkn2a, Atrx, and Pten to promote gliomagenesis in vivo in a mouse model of glioma. These tumors resemble proneural human mutant IDH1 glioblastoma and exhibit enhanced sensitivity to PARP inhibition in combination with chemotherapy. Keywords: IDH1, Cdkn2a, Atrx, Pten, glioma, mouse model, RCAS/TVA

Complete horizontal skin cell resurfacing and delayed vertical cell infiltration into porcine reconstructive tissue matrix compared to bovine collagen matrix and human dermis.

Science.gov (United States)

Mirastschijski, Ursula; Kerzel, Corinna; Schnabel, Reinhild; Strauss, Sarah; Breuing, Karl-Heinz

2013-10-01

Xenogenous dermal matrices are used for hernia repair and breast reconstruction. Full-thickness skin replacement is needed after burn or degloving injuries with exposure of tendons or bones. The authors used a human skin organ culture model to study whether porcine reconstructive tissue matrix (Strattice) is effective as a dermal tissue replacement. Skin cells or split-thickness skin grafts were seeded onto human deepidermized dermis, Strattice, and Matriderm. Cellular resurfacing and matrix infiltration were monitored by live fluorescence imaging, histology, and electron microscopy. Proliferation, apoptosis, cell differentiation, and adhesion were analyzed by immunohistochemistry. Epithelial resurfacing and vertical proliferation were reduced and delayed with both bioartificial matrices compared with deepidermized dermis; however, no differences in apoptosis, cell differentiation, or basement membrane formation were found. Vertical penetration was greatest on Matriderm, whereas no matrix infiltration was found on Strattice in the first 12 days. Uncompromised horizontal resurfacing was greatest with Strattice but was absent with Matriderm. Strattice showed no stimulatory effect on cellular inflammation. Matrix texture and surface properties governed cellular performance on tissues. Although dense dermal compaction delayed vertical cellular ingrowth for Strattice, it allowed uncompromised horizontal resurfacing. Dense dermal compaction may slow matrix decomposition and result in prolonged biomechanical stability of the graft. Reconstructive surgeons should choose the adequate matrix substitute depending on biomechanical requirements at the recipient site. Strattice may be suitable as a dermal replacement at recipient sites with high mechanical load requirements.

Communication between integrin receptors facilitates epicardial cell adhesion and matrix organization.

Science.gov (United States)

Pae, So Hyun; Dokic, Danijela; Dettman, Robert W

2008-04-01

Formation of the epicardium requires interactions between alpha(4)beta(1) integrin, and the extracellular matrix. We investigated the role of other integrins expressed by epicardial cells. We detected transcripts for alpha(5), alpha(8), alpha(v), beta(1), beta(3), and beta(5) integrins in the chick proepicardial organ (PE). We demonstrate that alpha(5)beta(1), alpha(8)beta(1), and alpha(v)beta(3) integrins are expressed by chick epicardial mesothelial cells (EMCs). Migration of EMCs in vitro was reduced by RGD-containing peptides. Using adenoviruses expressing an antisense to chick alpha(4) (AdGFPalpha4AS), full-length (Adhalpha4V5), and C-terminal deleted alpha(4) (Adhalpha4DeltaCV5), we found that EMCs were less able to adhere to vitronectin and fibronectin(120) indicating that alpha(4)beta(1) plays a role in regulating EMC adhesion to ligands of alpha(5)beta(1), alpha(8)beta(1), and alpha(v)beta(3). In Adhalpha4DeltaCV5-infected EMCs, alpha(5)beta(1) was diminished in fibrillar adhesions and new FN matrix assembly was abnormal. We propose that cooperation between alpha(4)beta(1) and RGD integrins is important for EMC adhesion and subepicardial matrix formation. (c) 2008 Wiley-Liss, Inc.

Silicon Promotes Exodermal Casparian Band Formation in Si-Accumulating and Si-Excluding Species by Forming Phenol Complexes.

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Alexander T Fleck

Full Text Available We studied the effect of Silicon (Si on Casparian band (CB development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS and flame ionization detector (GC-FID. Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols.

Matrix metalloproteinase-19 is highly expressed in astroglial tumors and promotes invasion of glioma cells

Czech Academy of Sciences Publication Activity Database

Lettau, I.; Hattermann, K.; Held-Feindt, J.; Brauer, Rena; Sedláček, Radislav; Mentlein, R.

2010-01-01

Roč. 69, č. 3 (2010), s. 215-223 ISSN 0022-3069 Institutional research plan: CEZ:AV0Z50520514 Keywords : extracellular matrix * MMP-28 * keratinocytes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.190, year: 2010

Loss of metal ions, disulfide reduction and mutations related to familial ALS promote formation of amyloid-like aggregates from superoxide dismutase.

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Zeynep A Oztug Durer

Full Text Available Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1 are one of the causes of familial amyotrophic lateral sclerosis (FALS. Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1 formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

Single-stranded nucleic acids promote SAMHD1 complex formation.

Science.gov (United States)

Tüngler, Victoria; Staroske, Wolfgang; Kind, Barbara; Dobrick, Manuela; Kretschmer, Stefanie; Schmidt, Franziska; Krug, Claudia; Lorenz, Mike; Chara, Osvaldo; Schwille, Petra; Lee-Kirsch, Min Ae

2013-06-01

SAM domain and HD domain-containing protein 1 (SAMHD1) is a dGTP-dependent triphosphohydrolase that degrades deoxyribonucleoside triphosphates (dNTPs) thereby limiting the intracellular dNTP pool. Mutations in SAMHD1 cause Aicardi-Goutières syndrome (AGS), an inflammatory encephalopathy that mimics congenital viral infection and that phenotypically overlaps with the autoimmune disease systemic lupus erythematosus. Both disorders are characterized by activation of the antiviral cytokine interferon-α initiated by immune recognition of self nucleic acids. Here we provide first direct evidence that SAMHD1 associates with endogenous nucleic acids in situ. Using fluorescence cross-correlation spectroscopy, we demonstrate that SAMHD1 specifically interacts with ssRNA and ssDNA and establish that nucleic acid-binding and formation of SAMHD1 complexes are mutually dependent. Interaction with nucleic acids and complex formation do not require the SAM domain, but are dependent on the HD domain and the C-terminal region of SAMHD1. We finally demonstrate that mutations associated with AGS exhibit both impaired nucleic acid-binding and complex formation implicating that interaction with nucleic acids is an integral aspect of SAMHD1 function.

Efficient diagonalization of the sparse matrices produced within the framework of the UK R-matrix molecular codes

Science.gov (United States)

Galiatsatos, P. G.; Tennyson, J.

2012-11-01

The most time consuming step within the framework of the UK R-matrix molecular codes is that of the diagonalization of the inner region Hamiltonian matrix (IRHM). Here we present the method that we follow to speed up this step. We use shared memory machines (SMM), distributed memory machines (DMM), the OpenMP directive based parallel language, the MPI function based parallel language, the sparse matrix diagonalizers ARPACK and PARPACK, a variation for real symmetric matrices of the official coordinate sparse matrix format and finally a parallel sparse matrix-vector product (PSMV). The efficient application of the previous techniques rely on two important facts: the sparsity of the matrix is large enough (more than 98%) and in order to get back converged results we need a small only part of the matrix spectrum.

The Role of Formative Feedback in Promoting Higher Order ...

African Journals Online (AJOL)

DrNneka

An International Multi-disciplinary Journal, Ethiopia. AFRREV ... make contribution to this research gap by proposing a theoretical feedback model that can promote higher order thinking skills in the classroom. The proposed ..... process; students provided with tasks that are novel, complex, creative, and non- algorithmic ...

Ab initio study of MgH2 formation

International Nuclear Information System (INIS)

Novakovic, Nikola; Matovic, Ljiljana; Novakovic, Jasmina Grbovic; Manasijevic, Miodrag; Ivanovic, Nenad

2009-01-01

Even if there is considerable literature dealing with structure and properties of MgH 2 compound there are still some uncertain details about nature of bonding governing its formation and decomposition. In order to better understand the processes essential for absorption and desorption of MgH 2 , ab initio DFT based calculations of rutile MgH 2 compound, elemental hcp-Mg, and three different hypothetical hcp-Mg-derived hydrides are performed. Our findings show that all structures are unstable, and that MgH (Wurtzite) is a closest possible candidate for intermediate phase between the hcp-Mg and MgH 2 at 1:1 stoichiometry. An alternative hydration pathway is suggested, including promotion of hcp-Mg to bcc-Mg and consecutive transformation to rutile MgH 2 by means of hydrogen incorporation into Mg matrix. Rutile MgH 2 calculations with various hydrogen vacancies concentration are performed. Calculation shows that at high hydrogen concentration close to 1:2, stable substoichiometric hydride is possible. Calculation also shows that high vacancy (low hydrogen) concentration favors bcc-Mg 2 H over rutile Mg 2 H structure.

Photoaffinity Labeling Studies on a Promoter of Dendritic Spine Formation

Science.gov (United States)

Sibucao, Kevin Carlo Abril

The small molecule BTA-EG4 has been shown to be a promoter of dendritic spine formation. The mechanism behind this phenomenon, however, is not well understood. The work in this dissertation is motivated by this gap in knowledge. The first part of this dissertation focuses on photoaffinity labeling studies to identify the cellular targets of BTA-EG4. Chapter 1 provides a summary of Alzheimer's disease, the rational design of BTA-EG 4, and methods to determine targets of small molecules. In Chapter 2, the synthesis of a BTA-EG4-based photoaffinity labeling probe and photodegradation studies are presented. Kinetic studies demonstrate that the probe photolyzes rapidly under UV light. In Chapter 3, photoaffinity labeling studies and subsequent protein identification experiments are reported. Competition experiments with the photoaffinity labeling probe and BTA-EG4 demonstrate that the probe labels a 55-kDa protein specifically. Tandem mass spectrometry revealed that the 55-kDa protein is the actin binding protein fascin 1. The second part of this dissertation focuses on the major protein identified from photoaffinity labeling studies, fascin 1. Chapter 4 provides a brief survey of the structure and function of fascin 1. In Chapter 5, characterizations of the interaction between BTA-EG4 and fascin 1 are reported. Isothermal titration calorimetry confirms the physical binding between fascin 1 and BTA-EG6, a BTA-EG4 analog. Slow speed sedimentation assays reveal that BTA-EG4 does not affect the actin-bundling activity of fascin 1. However, GST pull-down experiments show that BTA-EG4 inhibits the binding of fascin 1 with the GTPase Rab35. In addition, this work demonstrates that BTA-EG4 may be mechanistically distinct from the known fascin inhibitor G2.

Regulation of invadopodia formation and activity by CD147

Science.gov (United States)

Grass, G. Daniel; Bratoeva, Momka; Toole, Bryan P.

2012-01-01

A defining feature of malignant tumor progression is cellular penetration through the basement membrane and interstitial matrices that separate various cellular compartments. Accumulating evidence supports the notion that invasive cells employ specialized structures termed invadopodia to breach these structural barriers. Invadopodia are actin-based, lipid-raft-enriched membrane protrusions containing membrane-type-1 matrix metalloproteinase (MT1-MMP; also known as matrix metalloproteinase 14; MMP14) and several signaling proteins. CD147 (emmprin, basigin), an immunoglobulin superfamily protein that is associated with tumor invasion and metastasis, induces the synthesis of various matrix metalloproteinases in many systems. In this study we show that upregulation of CD147 is sufficient to induce MT1-MMP expression, invasiveness and formation of invadopodia-like structures in non-transformed, non-invasive, breast epithelial cells. We also demonstrate that CD147 and MT1-MMP are in close proximity within these invadopodia-like structures and co-fractionate in membrane compartments with the properties of lipid rafts. Moreover, manipulation of CD147 levels in invasive breast carcinoma cells causes corresponding changes in MT1-MMP expression, invasiveness and invadopodia formation and activity. These findings indicate that CD147 regulates invadopodia formation and activity, probably through assembly of MT1-MMP-containing complexes within lipid-raft domains of the invadopodia. PMID:22389410

Increase in Bacterial Colony Formation from a Permafrost Ice Wedge Dosed with a Tomitella biformata Recombinant Resuscitation-Promoting Factor Protein.

Science.gov (United States)

Puspita, Indun Dewi; Kitagawa, Wataru; Kamagata, Yoichi; Tanaka, Michiko; Nakatsu, Cindy H

2015-01-01

Resuscitation-promoting factor (Rpf) is a protein that has been found in a number of different Actinobacteria species and has been shown to promote the growth of active cells and resuscitate dormant (non-dividing) cells. We previously reported the biological activity of an Rpf protein in Tomitella biformata AHU 1821(T), an Actinobacteria isolated from a permafrost ice wedge. This protein is excreted outside the cell; however, few studies have investigated its contribution in environmental samples to the growth or resuscitation of bacteria other than the original host. Therefore, the aim of the present study was to determine whether Rpf from T. biformata impacted the cultivation of other bacteria from the permafrost ice wedge from which it was originally isolated. All experiments used recombinant Rpf proteins produced using a Rhodococcus erythropolis expression system. Dilutions of melted surface sterilized ice wedge samples mixed with different doses of the purified recombinant Rpf (rRpf) protein indicated that the highest concentration tested, 1250 pM, had a significantly (p permafrost sediments. The results of the present study demonstrated that rRpf not only promoted the growth of T. biformata from which it was isolated, but also enhanced colony formation by another Actinobacteria in an environmental sample.

rFN/Cad-11-Modified Collagen Type II Biomimetic Interface Promotes the Adhesion and Chondrogenic Differentiation of Mesenchymal Stem Cells