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Sample records for collagen xiii play

  1. Muscle-derived collagen XIII regulates maturation of the skeletal neuromuscular junction

    PubMed Central

    Latvanlehto, Anne; Fox, Michael A.; Sormunen, Raija; Tu, Hongmin; Oikarainen, Tuomo; Koski, Anu; Naumenko, Nikolay; Shakirzyanova, Anastasia; Kallio, Mika; Ilves, Mika; Giniatullin, Rashid; Sanes, Joshua R.; Pihlajaniemi, Taina

    2010-01-01

    Formation, maturation, stabilization and functional efficacy of the neuromuscular junction (NMJ) are orchestrated by transsynaptic and autocrine signals embedded within the synaptic cleft. Here, we demonstrate that collagen XIII, a non-fibrillar transmembrane collagen, is another such signal. We show that collagen XIII is expressed by muscle and its ectodomain can be proteolytically shed into the extracellular matrix. The collagen XIII protein was found present in the postsynaptic membrane and synaptic basement membrane. To identify a role for collagen XIII at the NMJ, mice were generated lacking this collagen. Morphological and ultrastructural analysis of the NMJ revealed incomplete adhesion of pre- and postsynaptic specializations in collagen XIII-deficient mice of both gender. Strikingly, Schwann cells erroneously enwrapped nerve terminals and invaginated into the synaptic cleft resulting in a decreased contact surface for neurotransmission. Consistent with morphological findings, electrophysiological studies indicated both post- and presynaptic defects in Col13a1−/− mice such as decreased amplitude of postsynaptic potentials, diminished probabilities of spontaneous release, and reduced readily releasable neurotransmitter pool. To identify the role of collagen XIII at the NMJ, shed ectodomain of collagen XIII was applied to cultured myotubes, and it was found to advance acetylcholine receptor (AChR) cluster maturation. Together with the delay in AChR cluster development observed in collagen XIII-deficient mutants in vivo, these results suggest that collagen XIII plays an autocrine role in postsynaptic maturation of the NMJ. Altogether the results presented here reveal that collagen XIII is a novel muscle-derived cue necessary for the maturation and function of the vertebrate NMJ. PMID:20844119

  2. Overexpression of collagen XIII in extraocular fat affected by active thyroid-associated ophthalmopathy: A crucial piece of the puzzle?

    PubMed

    Morris, Olivia Claire; Schebitz Walter, Kirsten; Telemo, Esbjörn; Hintschich, Christoph

    2016-08-01

    Thyroid-associated ophthalmopathy (TAO) causes irreversible increase in extraocular fat volume that contributes to the risk of exophthalmos and compressive optic neuropathy. Collagen XIII is implicated in uncontrolled cell growth in some tumours, but we are not aware of any studies of collagen XIII in TAO-affected solid tissue to date. We conducted immunohistochemical staining for collagen XIII alpha 1 (COL13A1), present in both the transmembrane and cleaved forms of collagen XIII, in consecutive prospectively collected human extraocular tissue specimens from patients with TAO and controls. We identified overexpression of collagen XIII in active TAO-affected fat. We discuss how species and cell-type specific responses of collagen XIII to stressors may help explain the different phenotypes of TAO. PMID:27245701

  3. A novel component of epidermal cell-matrix and cell-cell contacts: transmembrane protein type XIII collagen.

    PubMed

    Peltonen, S; Hentula, M; Hägg, P; Ylä-Outinen, H; Tuukkanen, J; Lakkakorpi, J; Rehn, M; Pihlajaniemi, T; Peltonen, J

    1999-10-01

    Type XIII collagen is a short chain collagen which has recently been shown to be a transmembrane protein. The purpose of this study was to elucidate the presence and localization of type XIII collagen in normal human skin and cultured keratinocytes. Expression of type XIII collagen was demonstrated in normal human skin and epidermis at the RNA level using reverse transcription followed by polymerase chain reaction and at the protein level using western blotting and indirect immunofluorescence labeling. Immunolabeling of epidermis revealed type XIII collagen both in the cell-cell contact sites and in the dermal-epidermal junction. In cultured keratinocytes type XIII collagen epitopes were detected in focal contacts and in intercellular contacts. The results of this study show very little colocalization of type XIII collagen and desmosomal components at the light microscopic level. Thus, these results suggest that type XIII collagen is unlikely to be a component of desmosomes. Instead, the punctate labeling pattern of type XIII collagen at the cell-cell contact sites and high degree of colocalization with E-cadherin suggests that type XIII collagen is very likely to be closely associated with adherens type junctions, and may, in fact, be a component of these junctions. PMID:10504453

  4. Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction

    NASA Technical Reports Server (NTRS)

    Woodley, D. T.; Yamauchi, M.; Wynn, K. C.; Mechanic, G.; Briggaman, R. A.

    1991-01-01

    provide evidence that collagen telopeptide sites play a role in collagen gel lattice contraction.

  5. Gene structure for the. alpha. 1 chain of a human short-chain collagen (type XIII) with alternatively spliced transcripts and translation termination codon at the 5' end of the last exon

    SciTech Connect

    Tikka, L.; Pihlajaniemi, T.; Henttu, P.; Prockop, D.J.; Tryggvason, K. )

    1988-10-01

    Two overlapping human genomic clones that encode a short-chain collagen, designated {alpha}1(XIII), were isolated by using recently described cDNA clones. Characterization of the cosmid clones that span {approx} 65,000 base pairs (bp) of the 3' end of the gene established several unusual features of this collagen gene. The last exon encodes solely the 3' untranslated region and it begins with a complete stop codon. The 10 adjacent exons vary in size from 27 to 87 bp and two of them are 54 bp. Therefore, the {alpha}1-chain gene of type XIII collagen has some features found in genes for fibrillar collagens but other features that are distinctly different. Previous analysis of overlapping cDNA clones and nuclease S1 mapping of mRNAs indicated one alternative splicing site causing a deletion of 36 bp from the mature mRNA. The present study showed that the 36 bp is contained within the gene as a single exon and also that the gene has a 45-bp -Gly-Xaa-Xaa- repeat coding exon not found in the cDNA clones previously characterized. Nuclease S1 mapping experiments indicated that this 45-bp exon is found in normal human skin fibroblast mRNAs. Accordingly, the data demonstrate that there is alternative splicing of at least two exons of the type {alpha}1(XIII)-chain gene.

  6. Congenital Myasthenic Syndrome Type 19 Is Caused by Mutations in COL13A1, Encoding the Atypical Non-fibrillar Collagen Type XIII α1 Chain

    PubMed Central

    Logan, Clare V.; Cossins, Judith; Rodríguez Cruz, Pedro M.; Parry, David A.; Maxwell, Susan; Martínez-Martínez, Pilar; Riepsaame, Joey; Abdelhamed, Zakia A.; Lake, Alice V.R.; Moran, Maria; Robb, Stephanie; Chow, Gabriel; Sewry, Caroline; Hopkins, Philip M.; Sheridan, Eamonn; Jayawant, Sandeep; Palace, Jacqueline; Johnson, Colin A.; Beeson, David

    2015-01-01

    The neuromuscular junction (NMJ) consists of a tripartite synapse with a presynaptic nerve terminal, Schwann cells that ensheathe the terminal bouton, and a highly specialized postsynaptic membrane. Synaptic structural integrity is crucial for efficient signal transmission. Congenital myasthenic syndromes (CMSs) are a heterogeneous group of inherited disorders that result from impaired neuromuscular transmission, caused by mutations in genes encoding proteins that are involved in synaptic transmission and in forming and maintaining the structural integrity of NMJs. To identify further causes of CMSs, we performed whole-exome sequencing (WES) in families without an identified mutation in known CMS-associated genes. In two families affected by a previously undefined CMS, we identified homozygous loss-of-function mutations in COL13A1, which encodes the alpha chain of an atypical non-fibrillar collagen with a single transmembrane domain. COL13A1 localized to the human muscle motor endplate. Using CRISPR-Cas9 genome editing, modeling of the COL13A1 c.1171delG (p.Leu392Sfs∗71) frameshift mutation in the C2C12 cell line reduced acetylcholine receptor (AChR) clustering during myotube differentiation. This highlights the crucial role of collagen XIII in the formation and maintenance of the NMJ. Our results therefore delineate a myasthenic disorder that is caused by loss-of-function mutations in COL13A1, encoding a protein involved in organization of the NMJ, and emphasize the importance of appropriate symptomatic treatment for these individuals. PMID:26626625

  7. Congenital Myasthenic Syndrome Type 19 Is Caused by Mutations in COL13A1, Encoding the Atypical Non-fibrillar Collagen Type XIII α1 Chain.

    PubMed

    Logan, Clare V; Cossins, Judith; Rodríguez Cruz, Pedro M; Parry, David A; Maxwell, Susan; Martínez-Martínez, Pilar; Riepsaame, Joey; Abdelhamed, Zakia A; Lake, Alice V R; Moran, Maria; Robb, Stephanie; Chow, Gabriel; Sewry, Caroline; Hopkins, Philip M; Sheridan, Eamonn; Jayawant, Sandeep; Palace, Jacqueline; Johnson, Colin A; Beeson, David

    2015-12-01

    The neuromuscular junction (NMJ) consists of a tripartite synapse with a presynaptic nerve terminal, Schwann cells that ensheathe the terminal bouton, and a highly specialized postsynaptic membrane. Synaptic structural integrity is crucial for efficient signal transmission. Congenital myasthenic syndromes (CMSs) are a heterogeneous group of inherited disorders that result from impaired neuromuscular transmission, caused by mutations in genes encoding proteins that are involved in synaptic transmission and in forming and maintaining the structural integrity of NMJs. To identify further causes of CMSs, we performed whole-exome sequencing (WES) in families without an identified mutation in known CMS-associated genes. In two families affected by a previously undefined CMS, we identified homozygous loss-of-function mutations in COL13A1, which encodes the alpha chain of an atypical non-fibrillar collagen with a single transmembrane domain. COL13A1 localized to the human muscle motor endplate. Using CRISPR-Cas9 genome editing, modeling of the COL13A1 c.1171delG (p.Leu392Sfs(∗)71) frameshift mutation in the C2C12 cell line reduced acetylcholine receptor (AChR) clustering during myotube differentiation. This highlights the crucial role of collagen XIII in the formation and maintenance of the NMJ. Our results therefore delineate a myasthenic disorder that is caused by loss-of-function mutations in COL13A1, encoding a protein involved in organization of the NMJ, and emphasize the importance of appropriate symptomatic treatment for these individuals. PMID:26626625

  8. Genetics Home Reference: factor XIII deficiency

    MedlinePlus

    ... This protein plays a critical role in the coagulation cascade, which is a series of chemical reactions ... Biswas A, Ivaskevicius V, Thomas A, Oldenburg J. Coagulation factor XIII deficiency. Diagnosis, prevalence and management of ...

  9. Arf6 plays an early role in platelet activation by collagen and convulxin.

    PubMed

    Choi, Wangsun; Karim, Zubair A; Whiteheart, Sidney W

    2006-04-15

    Small GTPases play critical roles in hemostasis, though the roster of such molecules in platelets is not complete. In this study, we report the presence of Ras-related GTPases of the ADP-ribosylation factor (Arf) family. Platelets contain Arf1 or 3 and Arf6, with the latter being predominantly membrane associated. Using effector domain pull-down assays, we show, counter to other GTPases, that Arf6-GTP is present in resting platelets and decreases rapidly upon activation with collagen or convulxin. This decrease does not completely rely on secondary agonists (ADP and thromboxane A2) or require integrin signaling. The decrease in free Arf6-GTP temporally precedes activation of Rho family GTPases (RhoA, Cdc42, and Rac1). Using a membrane-permeant, myristoylated peptide, which mimics the N-terminus of Arf6, we show that the Arf6-GTP decrease is essential for collagen- and convulxin-induced aggregation, platelet adherence, and spreading on collagen-coated glass. Treatment with this peptide also affects the activation of Rho family GTPases, but has little effect on RalA and Rap1 or on agonist-induced calcium mobilization. These data show that Arf6 is a key element in activation through GPVI, and is required for activation of the Rho family GTPases and the subsequent cytoskeletal rearrangements needed for full platelet function. PMID:16352809

  10. GPVI and α2β1 play independent critical roles during platelet adhesion and aggregate formation to collagen under flow

    PubMed Central

    Sarratt, Kendra L.; Chen, Hong; Zutter, Mary M.; Santoro, Samuel A.; Hammer, Daniel A.; Kahn, Mark L.

    2005-01-01

    The roles of the 2 major platelet-collagen receptors, glycoprotein VI (GPVI) and integrin α2β1, have been intensely investigated using a variety of methods over the past decade. In the present study, we have used pharmacologic and genetic approaches to study human and mouse platelet adhesion to collagen under flow conditions. Our studies demonstrate that both GPVI and integrin α2β1 play significant roles for platelet adhesion to collagen under flow and that the loss of both receptors completely ablates this response. Intracellular signaling mediated by the cytoplasmic adaptor Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76) but not by the transmembrane adaptor linker for activation of T cells (LAT) is critical for platelet adhesion to collagen under flow. In addition, reduced GPVI receptor density results in severe defects in platelet adhesion to collagen under flow. Defective adhesion to collagen under flow is associated with prolonged tail-bleeding times in mice lacking one or both collagen receptors. These studies establish platelet-collagen responses under physiologic flow as the consequence of a close partnership between 2 structurally distinct receptors and suggest that both receptors play significant hemostatic roles in vivo. PMID:15886326

  11. Plasma factor XIII and platelet factor XIII in hyperlipaemia.

    PubMed

    Cucuianu, M P; Miloszewski, K; Porutiu, D; Losowsky, M S

    1976-12-31

    Plasma factor XIII activity measured by a quantitative assay was found to be significantly higher in hypertriglyceridaemic patients (type IV and combined hyperlipoproteinaemia), as compared to normolipaemic controls. No such elevation in plasma factor XIII activity was found in patients with type Ha hyperlipaemia. Plasma pseudocholinesterase was found to parallel the elevated factor XIII activity in hypertriglyceridaemic subjects. In contrast, platelet factor XIII activity was not raised in hyperlipaemic subjects, and plasma factor XIII was found to be normal in a normolipaemic subjects with thrombocythaemia. It was concluded that there is no significant contribution from platelets to plasma factor XIII activity, and that the observed increase in plasma factor XIII in hypertriglyceridaemia results from enhanced hepatic synthesis of the enzyme. PMID:1037152

  12. NLRP3 Inflammasome Plays an Important Role in the Pathogenesis of Collagen-Induced Arthritis

    PubMed Central

    Zhang, Yongfeng; Zheng, Yi; Li, Hongbin

    2016-01-01

    Objective. To investigate the relationship between NLRP3 and the pathogenesis of collagen-induced arthritis. Methods. We used the collagen-induced arthritis (CIA) mouse model. The mice were divided into two groups: the model group (CIA, n = 16) and the control group (Normal, n = 8). The mice were sacrificed seven weeks after immunization. The arthritis score and imaging evaluation (X-rays, Micro-CT, and MRI) were performed. Synovial tissue NLRP3 expression and peripheral blood cytokine levels were analyzed. Results. The arthritis score (6.00 ± 2.52), imaging score (4.63 ± 0.92), and synovial tissue NLRP3 expression (4.00 ± 2.03) significantly increased in the CIA mice. The expression of synovial NLRP3 was positively correlated with arthritis clinical and radiographic scores (r = 0.792 and r = 0.669, resp.). Conclusions. The synovial NLRP3 expression increased at the early onset of RA. Synovial NLRP3 expression level was correlated with the clinical arthritis severity and extent of radiological destruction, suggesting that NLRP3 is involved in the pathogenesis of RA. PMID:27034595

  13. Play.

    ERIC Educational Resources Information Center

    Rogers, Fred; Sharapan, Hedda

    1993-01-01

    Contends that, in childhood, work and play seem to come together. Says that for young children their play is their work, and the more adults encourage children to play, the more they emphasize important lifelong resource. Examines some uses of children's play, making and building, artwork, dramatic play, monsters and superheroes, gun play, and…

  14. The NC16A Domain of Collagen XVII Plays a Role in Triple Helix Assembly and Stability*

    PubMed Central

    Van den Bergh, Françoise; Fu, Chang-Ling; Olague-Marchan, Monica; Giudice, George J.

    2007-01-01

    Collagen XVII/BP180 is a transmembrane constituent of the epidermal anchoring complex. To study the role of its non-collagenous linker domain, NC16A, in protein assembly and stability, we analyzed the following recombinant proteins: the collagen XVII extracellular domain with or without NC16A, and a pair of truncated proteins comprising the COL15-NC15 stretch expressed with or without NC16A. All four proteins were found to exist as stable collagen triple helices; however, the two missing NC16A exhibited melting temperatures significantly lower than their NC16A-containing counterparts. Protein refolding experiments revealed that the rate of triple helix assembly of the collagen model peptide GPP10 is greatly increased by the addition of an upstream NC16A domain. In summary, the NC16A linker domain of collagen XVII exhibits a positive effect on both the rate of assembly and the stability of the adjoining collagen structure. PMID:17045967

  15. Play

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    Designing a game with a serious purpose involves considering the worlds of Reality and Meaning yet it is undeniably impossible to create a game without a third world, one that is specifically concerned with what makes a game a game: the play elements. This third world, the world of people like designers and artists, and disciplines as computer science and game design, I call the world of Play and this level is devoted to it. The level starts off with some of the misperceptions people have of play. Unlike some may think, we play all the time, even when we grow old—this was also very noticeable in designing the game Levee Patroller as the team exhibited very playful behavior at many occasions. From there, I go into the aspects that characterize this world. The first concerns the goal of the game. This relates to the objectives people have to achieve within the game. This is constituted by the second aspect: the gameplay. Taking actions and facing challenges is subsequently constituted by a gameworld, which concerns the third aspect. And all of it is not possible without the fourth and final aspect, the type of technology that creates and facilitates the game. The four aspects together make up a “game concept” and from this world such a concept can be judged on the basis of three closely interrelated criteria: engagement, immersion, and fun.

  16. Matrix Metalloproteinase 2 (MMP-2) Plays a Critical Role in the Softening of Common Carp Muscle during Chilled Storage by Degradation of Type I and V Collagens.

    PubMed

    Xu, Chao; Wang, Cheng; Cai, Qiu-Feng; Zhang, Qian; Weng, Ling; Liu, Guang-Ming; Su, Wen-Jin; Cao, Min-Jie

    2015-12-30

    Matrix metalloproteinases (MMPs) are proposed to play important roles in the degradation of collagens, thus causing the post-mortem softening of fish muscle, although the specific mechanism remains largely unresolved. Previously, we reported the existence of gelatinase-like proteinases in common carp (Cyprinus carpio) muscle. The primary structures of these proteinases, however, have never been investigated. In the present study, two MMPs with molecular masses of 66 and 65 kDa were purified to homogeneity from common carp muscle by ammonium sulfate fractionation and a series of column chromatographies. Matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS/MS) analysis indicated that they are completely identical to MMP-2 from common carp. During chilled storage of common carp at 4 °C, the enzymatic activity of MMP-2 increased to 212% in 12 h while the texture profile increased over the first 2 h and gradually decreased. On the other hand, type V collagen was purified to homogeneity and a specific polyclonal antibody against this protein was prepared. Both type I and V collagens were effectively hydrolyzed by MMP-2 at 30 °C and even at 4 °C. Furthermore, injection of metalloproteinase proteinase inhibitor EDTA into the blood vessel of live common carp suppressed post-mortem tenderization significantly. All of these results confirmed that MMP-2 is a major proteinase responsible for the degradation of collagens, resulting in the softening of fish muscle during chilled storage. PMID:26653826

  17. The Collagen Family

    PubMed Central

    Ricard-Blum, Sylvie

    2011-01-01

    Collagens are the most abundant proteins in mammals. The collagen family comprises 28 members that contain at least one triple-helical domain. Collagens are deposited in the extracellular matrix where most of them form supramolecular assemblies. Four collagens are type II membrane proteins that also exist in a soluble form released from the cell surface by shedding. Collagens play structural roles and contribute to mechanical properties, organization, and shape of tissues. They interact with cells via several receptor families and regulate their proliferation, migration, and differentiation. Some collagens have a restricted tissue distribution and hence specific biological functions. PMID:21421911

  18. Factor XIII: Structure and Function.

    PubMed

    Schroeder, Verena; Kohler, Hans P

    2016-06-01

    Over the last two decades, it became evident that factor XIII (FXIII) is not only a crucial determinant of clot characteristics but also has potentially important functions in many various fields such as bone biology, immunity, and adipogenesis. In this review, we aim to summarize the latest findings regarding structure and function of FXIII. In regard to FXIII structure, much progress has been made recently to understand how its subunits are held together. In the A subunit, the activation peptide has a crucial role in the formation of FXIII-A2 dimers. In the B subunit, Sushi domains that are involved in binding to the A subunit and in B2 dimer formation have been identified. In regard to FXIII function, interactions with immune cells and the complement system have been described. A novel function of FXIII-A in adipogenesis has been suggested. The role of FXIII-A in osteoblast differentiation has been further investigated; however, a novel double knockout mouse deficient in both FXIII-A and transglutaminase 2 showed normal bone formation. Thus, more research, in particular, into the cellular functions of FXIII-A is still required. PMID:27019464

  19. Interaction of factor XIII subunits.

    PubMed

    Katona, Eva; Pénzes, Krisztina; Csapó, Andrea; Fazakas, Ferenc; Udvardy, Miklós L; Bagoly, Zsuzsa; Orosz, Zsuzsanna Z; Muszbek, László

    2014-03-13

    Coagulation factor XIII (FXIII) is a heterotetramer consisting of 2 catalytic A subunits (FXIII-A2) and 2 protective/inhibitory B subunits (FXIII-B2). FXIII-B, a mosaic protein consisting of 10 sushi domains, significantly prolongs the lifespan of catalytic subunits in the circulation and prevents their slow progressive activation in plasmatic conditions. In this study, the biochemistry of the interaction between the 2 FXIII subunits was investigated. Using a surface plasmon resonance technique and an enzyme-linked immunosorbent assay-type binding assay, the equilibrium dissociation constant (Kd) for the interaction was established in the range of 10(-10) M. Based on the measured Kd, it was calculated that in plasma approximately 1% of FXIII-A2 should be in free form. This value was confirmed experimentally by measuring FXIII-A2 in plasma samples immunodepleted of FXIII-A2B2. Free plasma FXIII-A2 is functionally active, and when activated by thrombin and Ca(2+), it can cross-link fibrin. In cerebrospinal fluid and tears with much lower FXIII subunit concentrations, >80% of FXIII-A2 existed in free form. A monoclonal anti-FXIII-B antibody that prevented the interaction between the 2 subunits reacted with the recombinant combined first and second sushi domains of FXIII-B, and its epitope was localized to the peptide spanning positions 96 to 103 in the second sushi domain. PMID:24408323

  20. COLLAGEN STRUCTURE AND STABILITY

    PubMed Central

    Shoulders, Matthew D.; Raines, Ronald T.

    2010-01-01

    Collagen is the most abundant protein in animals. This fibrous, structural protein comprises a right-handed bundle of three parallel, left-handed polyproline II-type helices. Much progress has been made in elucidating the structure of collagen triple helices and the physicochemical basis for their stability. New evidence demonstrates that stereoelectronic effects and preorganization play a key role in that stability. The fibrillar structure of type I collagen–the prototypical collagen fibril–has been revealed in detail. Artificial collagen fibrils that display some properties of natural collagen fibrils are now accessible using chemical synthesis and self-assembly. A rapidly emerging understanding of the mechanical and structural properties of native collagen fibrils will guide further development of artificial collagenous materials for biomedicine and nanotechnology. PMID:19344236

  1. Localisation of factor XIII in human tissues using an immunoperoxidase technique.

    PubMed Central

    Fear, J D; Jackson, P; Gray, C; Miloszewski, K J; Losowsky, M S

    1984-01-01

    An immunoperoxidase technique has been used to localise clotting factor XIII subunits A and S in human tissues. The presence of factor XIII in placenta and megakaryocytes was confirmed. Factor XIII was also found in fibroblasts, a hitherto unreported finding. Factor XIII subunits were not detected in hepatocytes, although factor XIII was found in fibroblasts in portal tracts. These findings suggest that factor XIII is not synthesised in the liver as previously thought. Images PMID:6373832

  2. COLLAGEN PROCESSING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Collagen dispersions, produced from fibrils recovered from milled bovine collagen, have shown promise in environmental remediation in applications as settling aids, filtration aids, fractionation media, oil drop stabilizers, and water purification aids. Macroporous structures, processed by controll...

  3. [Anders Jahre Prize for Young Researchers 1994. The collagen family: new members and new concepts about their biosynthesis].

    PubMed

    Pihlajaniemi, T

    1995-01-01

    Nineteen distinct types of collagen have been found in vertebrates. Studies with newly discovered collagens have lead us to propose two new subgroups of collagens, namely membrane-associated collagens, including type XIII and XVII collagens, and a subgroup formed by the homologous collagens XV and XVIII. Type XIII collagen is found ubiquitously in the matrix, and in view of its plasma membrane localization it may function in cell adhesion. The new homologous collagens XV and XVIII are characterized by a collagenous sequence with frequent interruptions and large amino and carboxyterminal noncollagenous domains. Type XVIII collagen chains have three variant amino-terminal ends and one of these variants is characterized by a new cysteine-rich sequence motif, termed the fz sequence. A key enzyme of collagen biosynthesis is prolyl 4-hydroxylase consisting of two alpha and two beta subunits. The beta subunit is a multifunctional polypeptide with several distinct activities. Furthermore, two types of alpha subunit have been identified resulting in enzyme tetramers with highly similar properties with some interesting differences. PMID:7892127

  4. Bioengineered collagens

    PubMed Central

    Ramshaw, John AM; Werkmeister, Jerome A; Dumsday, Geoff J

    2014-01-01

    Mammalian collagen has been widely used as a biomedical material. Nevertheless, there are still concerns about the variability between preparations, particularly with the possibility that the products may transmit animal-based diseases. Many groups have examined the possible application of bioengineered mammalian collagens. However, translating laboratory studies into large-scale manufacturing has often proved difficult, although certain yeast and plant systems seem effective. Production of full-length mammalian collagens, with the required secondary modification to give proline hydroxylation, has proved difficult in E. coli. However, recently, a new group of collagens, which have the characteristic triple helical structure of collagen, has been identified in bacteria. These proteins are stable without the need for hydroxyproline and are able to be produced and purified from E. coli in high yield. Initial studies indicate that they would be suitable for biomedical applications. PMID:24717980

  5. 21 CFR 866.5330 - Factor XIII, A, S, immuno-logical test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Factor XIII, A, S, immuno-logical test system. 866.5330 Section 866.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN....5330 Factor XIII, A, S, immuno-logical test system. (a) Identification. A factor XIII, A,...

  6. 21 CFR 866.5330 - Factor XIII, A, S, immuno-logical test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Factor XIII, A, S, immuno-logical test system. 866.5330 Section 866.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN....5330 Factor XIII, A, S, immuno-logical test system. (a) Identification. A factor XIII, A,...

  7. 21 CFR 866.5330 - Factor XIII, A, S, immuno-logical test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Factor XIII, A, S, immuno-logical test system. 866.5330 Section 866.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN....5330 Factor XIII, A, S, immuno-logical test system. (a) Identification. A factor XIII, A,...

  8. 21 CFR 866.5330 - Factor XIII, A, S, immuno-logical test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Factor XIII, A, S, immuno-logical test system. 866.5330 Section 866.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN....5330 Factor XIII, A, S, immuno-logical test system. (a) Identification. A factor XIII, A,...

  9. Clinical Use of Factor XIII Concentrates.

    PubMed

    Lassila, Riitta

    2016-06-01

    Factor (F) XIII deficiency is a congenital rare bleeding disorder (RBD), with an estimated prevalence of 1 in 1 to 2 million individuals, and more than 1,200 patients have been diagnosed to date. In newborns, umbilical cord bleeding is typical, and later in life during trauma, surgery and even spontaneously prolonged bleeds, reproduction, and delivery complications occur frequently without appropriate replacement therapy. Also, an acquired form of FXIII deficiency may occur via massive bleeds or neutralizing antibodies. In the inherited form of FXIII deficiency, prophylaxis with FXIII concentrate is administered to prevent the very high risk of intracranial bleeds, the incidence being close to 30%. Laboratory diagnosis of FXIII deficiency is based on measuring plasma FXIII antigen and activity, and it is claimed that FXIII activity of around 5 IU/dL would suffice to protect from bleeds. However, at the low levels of detection, most FXIII methods are inaccurate, and quality controls and collaboration with reference laboratories are important to improve the accuracy of low-level FXIII measurements. The trough target for prophylaxis should be set to 10 to 20 IU/dL, which is achievable by administration of 25 to 35 IU/kg every 4 to 6 weeks. However, general risk factors influencing hemostasis should be carefully evaluated, including anemia and hypertension. Fibrin cross-linking by FXIII is of major importance and red cells bind to fibrin partially via platelets and FXIII to promote clot strength. Physiologically, platelets and macrophages contain FXIII providing cellular support; thus, the patients may benefit from platelet transfusion during problematic bleeds. Plasma-derived and recently a recombinant FXIII concentrate are available; however, the latter has mainly anecdotal data regarding management of bleeds and surgery, and its access is limited due to the high cost. The international registry RBD database, (RBDD) continues to gain cumulative knowledge, and

  10. Colorimetric assay of blood coagulation factor XIII in plasma.

    PubMed

    Lee, K N; Birckbichler, P J; Patterson, M K

    1988-05-01

    In this new colorimetric assay for Factor XIII in plasma, 5-(biotinamido)pentylamine is used as the amine substrate. Factor XIII, a zymogen, is transformed by thrombin and Ca2+ to active Factor XIIIa, and the incorporation of 5-(biotinamido)pentylamine into N,N-dimethylcasein is used to measure catalytically active Factor XIIIa. The biotinylated enzymatic product is immobilized onto 96-well microtiter plates, complexed with streptavidin-beta-galactosidase, and the absorbance at 405 nm is monitored for production of p-nitrophenol from p-nitrophenyl-beta-D-galactopyranoside. Concentrations of N,N-dimethylcasein, 5-(biotinamido)pentylamine, Ca2+, and thrombin were chosen to allow near-maximum velocity of amine incorporation. A linear relationship was obtained between assay product and plasma volume, from 0.5 to 50 microL of plasma. Results correlated well (r greater than 0.924) with those from the most frequently utilized radiometric filter-paper assay for Factor XIII. The method appears to be ideal for routine diagnostic estimation of Factor XIII in plasma because of its simplicity, its lack of use of radioisotopes, and its potential for assay of large numbers of samples by use of microtiter plates and automated plate readers. PMID:2897256

  11. Collagen fibril formation during development

    SciTech Connect

    Fleischmajer, R.; Perlish, J.S.; Timpl, R.; Olsen, B.R.

    1987-05-01

    Studies with embryonic skin and bone suggested that the aminopropeptide (AP) and carboxylpropeptide (CP) of type I pro-callagen (pro-col) play a role in fibril formation. Chick leg metatarsal tendons were studied by electron microscopy. AP and CP of type I pro-col were purified from chick leg tendons; antibodies developed in rabbits and purity tested by radioimmunoassays. Antibodies were used for immunofluorescence microscopy (IFM) and immunoblotting (IB). The peritendineum, consisting of thin 20-30 nm fibrils, revealed the AP of type I and type III procol. In the tendon area, collagen fibrils were arranged within small compartments and were of uniform diameter at 10d, 14d and 18d. However, beyond 21d, there was confluency of the compartments and a wide range of fibril diameters. IFM revealed fine streaks of collagen, staining with the AP of type I throughout the tendon. The CP was mainly intracellular with only a small amount present in the extracellular space. IB revealed procollagen, pN-collagen (AP+collagen) and pC-collagen, (CP+collagen) at all stages of development. Ratios of pN/pC collagen, determined by spectrophotometric scanning of autoradiographs, correlated well with the distribution of fibril diameter. This study suggests the hypothesis that AP initiates fibrillogenesis while CP may regulate additional fibril growth.

  12. Coated platelets function in platelet-dependent fibrin formation via integrin αIIbβ3 and transglutaminase factor XIII

    PubMed Central

    Mattheij, Nadine J.A.; Swieringa, Frauke; Mastenbroek, Tom G.; Berny-Lang, Michelle A.; May, Frauke; Baaten, Constance C.F.M.J.; van der Meijden, Paola E.J.; Henskens, Yvonne M.C.; Beckers, Erik A.M.; Suylen, Dennis P.L.; Nolte, Marc W.; Hackeng, Tilman M.; McCarty, Owen J.T.; Heemskerk, Johan W.M.; Cosemans, Judith M.E.M.

    2016-01-01

    Coated platelets, formed by collagen and thrombin activation, have been characterized in different ways: i) by the formation of a protein coat of α-granular proteins; ii) by exposure of procoagulant phosphatidylserine; or iii) by high fibrinogen binding. Yet, their functional role has remained unclear. Here we used a novel transglutaminase probe, Rhod-A14, to identify a subpopulation of platelets with a cross-linked protein coat, and compared this with other platelet subpopulations using a panel of functional assays. Platelet stimulation with convulxin/thrombin resulted in initial integrin αIIbβ3 activation, the appearance of a platelet population with high fibrinogen binding, (independently of active integrins, but dependent on the presence of thrombin) followed by phosphatidylserine exposure and binding of coagulation factors Va and Xa. A subpopulation of phosphatidylserine-exposing platelets bound Rhod-A14 both in suspension and in thrombi generated on a collagen surface. In suspension, high fibrinogen and Rhod-A14 binding were antagonized by combined inhibition of transglutaminase activity and integrin αIIbβ3. Markedly, in thrombi from mice deficient in transglutaminase factor XIII, platelet-driven fibrin formation and Rhod-A14 binding were abolished by blockage of integrin αIIbβ3. Vice versa, star-like fibrin formation from platelets of a patient with deficiency in αIIbβ3 (Glanzmann thrombasthenia) was abolished upon blockage of transglutaminase activity. We conclude that coated platelets, with initial αIIbβ3 activation and high fibrinogen binding, form a subpopulation of phosphatidylserine-exposing platelets, and function in platelet-dependent star-like fibrin fiber formation via transglutaminase factor XIII and integrin αIIbβ3. PMID:26721892

  13. 21 CFR 866.5330 - Factor XIII, A, S, immuno-logical test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Factor XIII, A, S, immuno-logical test system. 866.5330 Section 866.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunological Test Systems § 866.5330 Factor XIII, A, S, immuno-logical...

  14. Medical and Surgical Management of Postpartum Hemorrhage in a Woman with Factor XIII Deficiency

    PubMed Central

    Srey, Krisna; Canales, Alexander; Kiffin, Chauniqua; Ashmawy, Yessin

    2016-01-01

    Factor XIII deficiency is a rare inherited coagulopathy. Factor XIII is the last clotting factor in the coagulation cascade to insure strength and stability to fibrin clots. Without this enzyme, the fibrous clot is unstable and nonresistant to fibrinolysis. Gravid women with this congenital disease are especially at risk for complications including miscarriages and hemorrhage without appropriate interventions. We present a case of a woman in her 20s with Factor XIII deficiency who was treated with cryoprecipitate and had a successful normal spontaneous vaginal delivery; subsequently, patient suffered from postpartum hemorrhage and consumptive coagulopathy due to consumption of Factor XIII, requiring emergency surgical intervention. Intraoperative management was challenged by an ethical dilemma involving the patient's religious beliefs about not receiving blood. This paper will discuss the mechanism of Factor XIII and the medical and surgical management involved with this patient.

  15. Heterogeneity of Collagen VI Microfibrils

    PubMed Central

    Maaß, Tobias; Bayley, Christopher P.; Mörgelin, Matthias; Lettmann, Sandra; Bonaldo, Paolo; Paulsson, Mats; Baldock, Clair; Wagener, Raimund

    2016-01-01

    Collagen VI, a collagen with uncharacteristically large N- and C-terminal non-collagenous regions, forms a distinct microfibrillar network in most connective tissues. It was long considered to consist of three genetically distinct α chains (α1, α2, and α3). Intracellularly, heterotrimeric molecules associate to form dimers and tetramers, which are then secreted and assembled to microfibrils. The identification of three novel long collagen VI α chains, α4, α5, and α6, led to the question if and how these may substitute for the long α3 chain in collagen VI assembly. Here, we studied structural features of the novel long chains and analyzed the assembly of these into tetramers and microfibrils. N- and C-terminal globular regions of collagen VI were recombinantly expressed and studied by small angle x-ray scattering (SAXS). Ab initio models of the N-terminal globular regions of the α4, α5, and α6 chains showed a C-shaped structure similar to that found for the α3 chain. Single particle EM nanostructure of the N-terminal globular region of the α4 chain confirmed the C-shaped structure revealed by SAXS. Immuno-EM of collagen VI extracted from tissue revealed that like the α3 chain the novel long chains assemble to homotetramers that are incorporated into mixed microfibrils. Moreover, SAXS models of the C-terminal globular regions of the α1, α2, α4, and α6 chains were generated. Interestingly, the α1, α2, and α4 C-terminal globular regions dimerize. These self-interactions may play a role in tetramer formation. PMID:26742845

  16. Oleanane-type triterpene saponins with collagen synthesis-promoting activity from the flowers of Bellis perennis.

    PubMed

    Morikawa, Toshio; Ninomiya, Kiyofumi; Takamori, Yasunobu; Nishida, Eriko; Yasue, Misato; Hayakawa, Takao; Muraoka, Osamu; Li, Xuezheng; Nakamura, Seikou; Yoshikawa, Masayuki; Matsuda, Hisashi

    2015-08-01

    The methanol extract from Bellis perennis (Asteraceae) flowers was found to promote collagen synthesis in normal human dermal fibroblasts (NHDFs). Seven oleanane-type triterpene saponins, perennisosides XIII-XIX, and two known saponins, bellissaponins BS5 and BS9, were isolated from the methanol extract. The structures were determined based on chemical and physicochemical data, and confirmed using previously isolated related compounds as references. Among the isolates, including 19 previously reported saponins, perennisosides XVIII, I, II, VII, IX, and XI, asterbatanoside D, bernardioside B2, and bellissaponins BS5 and BS9 significantly promoted collagen synthesis at 3-30μM without cytotoxicity. PMID:26028520

  17. Acquired coagulation factor XIII deficiency: a case report.

    PubMed

    Jia, Yongqing; Hu, Huixian; Wei, Bin

    2016-06-01

    The main objective of the study is to summarize the clinical characteristics of acquired factor XIII (FXIII) deficiency caused by a spontaneous FXIII inhibitor. Here we report a new case of acquired FXIII deficiency caused by FXIII inhibitor and review the medical literature regarding the characteristics and treatment of this disorder. FXIII deficiency caused by FXIII inhibitors is rare and of uncertain pathogenesis. Experience with therapeutic measures is limited to data from case reports. Immunosuppressive drugs may reduce autoantibodies or inhibit the cell clone generating the antibodies and may have been of benefit in our patient. The impact of such therapy on patient prognosis is incompletely known. PMID:26588447

  18. Nonlinear optical response of the collagen triple helix and second harmonic microscopy of collagen liquid crystals

    NASA Astrophysics Data System (ADS)

    Deniset-Besseau, A.; De Sa Peixoto, P.; Duboisset, J.; Loison, C.; Hache, F.; Benichou, E.; Brevet, P.-F.; Mosser, G.; Schanne-Klein, M.-C.

    2010-02-01

    Collagen is characterized by triple helical domains and plays a central role in the formation of fibrillar and microfibrillar networks, basement membranes, as well as other structures of the connective tissue. Remarkably, fibrillar collagen exhibits efficient Second Harmonic Generation (SHG) and SHG microscopy proved to be a sensitive tool to score fibrotic pathologies. However, the nonlinear optical response of fibrillar collagen is not fully characterized yet and quantitative data are required to further process SHG images. We therefore performed Hyper-Rayleigh Scattering (HRS) experiments and measured a second order hyperpolarisability of 1.25 10-27 esu for rat-tail type I collagen. This value is surprisingly large considering that collagen presents no strong harmonophore in its amino-acid sequence. In order to get insight into the physical origin of this nonlinear process, we performed HRS measurements after denaturation of the collagen triple helix and for a collagen-like short model peptide [(Pro-Pro-Gly)10]3. It showed that the collagen large nonlinear response originates in the tight alignment of a large number of weakly efficient harmonophores, presumably the peptide bonds, resulting in a coherent amplification of the nonlinear signal along the triple helix. To illustrate this mechanism, we successfully recorded SHG images in collagen liquid solutions by achieving liquid crystalline ordering of the collagen triple helices.

  19. New developments in the management of congenital Factor XIII deficiency

    PubMed Central

    Fadoo, Zehra; Merchant, Quratulain; Rehman, Karim Abdur

    2013-01-01

    Congenital Factor XIII (FXIII) deficiency is a rare, inherited, autosomal recessive coagulation disorder. Most mutations of this condition are found in the A-subunit with almost half these being missense mutations. Globally, approximately one in three million people suffer from this deficiency. Factor XIII deficiency is associated with severe life threatening bleeding, intracranial hemorrhage, impaired wound healing, and recurrent pregnancy losses. FXIII is known to have a potential role in mediating inflammatory processes, insulin resistance, bone metabolism, neoplasia, and angiogenesis. The algorithm provided for FXIII diagnosis and classification will enable prompt identification and early intervention for controlling potential life threatening complications. Prophylactic replacement therapy using blood products containing FXIII such as fresh frozen plasma, cryoprecipitate, or using FXIII concentrate remains the mainstay for the management of FXIII deficiency. In most parts of the world, cryoprecipitate and plasma transfusions are the only treatments available. Management developments have revealed the effectiveness and safety of recombinant FXIII concentrate for prophylaxis and treatment. The aim of this review is to provide an overview of advancements made in the management of FXIII deficiency from the time it was first detected, highlighting novel developments made in recent years. Greater research is warranted in identifying novel approaches to manage FXIII deficiency in light of its underlying pathophysiology. PMID:23761984

  20. Biomedical applications of collagens.

    PubMed

    Ramshaw, John A M

    2016-05-01

    Collagen-based biomedical materials have developed into important, clinically effective materials used in a range of devices that have gained wide acceptance. These devices come with collagen in various formats, including those based on stabilized natural tissues, those that are based on extracted and purified collagens, and designed composite, biosynthetic materials. Further knowledge on the structure and function of collagens has led to on-going developments and improvements. Among these developments has been the production of recombinant collagen materials that are well defined and are disease free. Most recently, a group of bacterial, non-animal collagens has emerged that may provide an excellent, novel source of collagen for use in biomaterials and other applications. These newer collagens are discussed in detail. They can be modified to direct their function, and they can be fabricated into various formats, including films and sponges, while solutions can also be adapted for use in surface coating technologies. PMID:26448097

  1. Collagen vascular disease

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/001223.htm Collagen vascular disease To use the sharing features on ... were previously said to have "connective tissue" or "collagen vascular" disease. We now have names for many ...

  2. Planck 2013 results. XIII. Galactic CO emission

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Alves, M. I. R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cardoso, J.-F.; Catalano, A.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Dempsey, J. T.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Fukui, Y.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Handa, T.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hily-Blant, P.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jewell, J.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Moore, T. J. T.; Morgante, G.; Morino, J.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Nakajima, T.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Okuda, T.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Thomas, H. S.; Toffolatti, L.; Tomasi, M.; Torii, K.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Yamamoto, H.; Yoda, T.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    Rotational transition lines of CO play a major role in molecular radio astronomy as a mass tracer and in particular in the study of star formation and Galactic structure. Although a wealth of data exists for the Galactic plane and some well-known molecular clouds, there is no available high sensitivity all-sky survey of CO emission to date. Such all-sky surveys can be constructed using the Planck HFI data because the three lowest CO rotational transition lines at 115, 230 and 345 GHz significantly contribute to the signal of the 100, 217 and 353 GHz HFI channels, respectively. Two different component separation methods are used to extract the CO maps from Planck HFI data. The maps obtained are then compared to one another and to existing external CO surveys. From these quality checks the best CO maps, in terms of signal to noise ratio and/or residual contamination by other emission, are selected. Three different sets of velocity-integrated CO emission maps are produced with different trade-offs between signal-to-noise, angular resolution, and reliability. Maps for the CO J = 1 → 0, J = 2 → 1, and J = 3 → 2 rotational transitions are presented and described in detail. They are shown to be fully compatible with previous surveys of parts of the Galactic plane as well as with undersampled surveys of the high latitude sky. The Planck HFI velocity-integrated CO maps for the J = 1 → 0, J = 2 → 1, and J = 3 →2 rotational transitions provide an unprecedented all-sky CO view of the Galaxy. These maps are also of great interest to monitor potential CO contamination of the Planck studies of the cosmological microwave background.

  3. [Intradural hematoma of the foramen magnum associated with factor XIII deficiency].

    PubMed

    Donnet, A; Trefouret, S; Alessi, M C; Harlé, J R; Graziani, N; Grisoli, F

    1994-01-01

    A 50-year-old woman, with a history of IgG monoclonal gammapathy, presented with meningitis and intradural hematoma of the foramen magnum associated with factor XIII deficiency. The patient died postoperatively of diffuse haemorrhage. Inhibitors to factor XIII are extremely rare and are congenital or acquired. Patients with factor XIII inhibitor can experience severe bleeding, and many died of cerebral haemorrhage. The role of this defect is discussed. We recommend an extensive investigation of haemostasis for patients with both episode of haemorrhagic disorder and monoclonal gammapathy. PMID:7863159

  4. Mild factor XIII deficiency and concurrent hypofibrinogenemia: effect of pregnancy.

    PubMed

    Kaveney, Amanda D; Philipp, Claire S

    2016-06-01

    Factor XIII (FXIII) deficiency is a rare bleeding disorder. Patients with mild congenital FXIII deficiency tend to be asymptomatic, but may demonstrate significant bleeding symptoms with surgery, trauma, and pregnancy. Postpartum hemorrhage has been described in mild FXIII deficiency. We present a case of mild FXIII deficiency and concurrent hypofibrinogenemia manifested by recurrent postpartum hemorrhage, menorrhagia, and miscarriage. Mutational analysis identified a previously unreported heterozygous mutation of the FXIIIA subunit (p.Trp315Arg). No mutation was noted in the fibrinogen gene. FXIII levels decreased approximately 50% from nonpregnant levels to their nadir during labor, whereas fibrinogen levels rose approximately 1.5-fold from decreased nonpregnant levels to their peak at the time of labor. This case illustrates the course of mild FXIII and fibrinogen deficiencies during pregnancy, labor, and postpartum, and raises possible management options for prevention of antepartum and postpartum hemorrhage in women with these deficiencies. PMID:26575494

  5. Quantity change in collagen following 830-nm diode laser welding

    NASA Astrophysics Data System (ADS)

    Tang, Jing; O'Callaghan, David; Rouy, Simone; Godlewski, Guilhem; Prudhomme, Michel

    1996-12-01

    The actual mechanism for production of laser welding of tissue is presently unknown, but collagen plays an important role is tissue welded after laser irradiance. The quantity change in collagen extracted from the abdominal aorta of Wistar rats after tissue welding using an 830 nm diode laser was investigated. The collagen contents following repeated pepsin digestion after acetic acid extraction were determined with Sircol collagen assay. Compared with untreated aorta, the collagen content of the treated vessel was obvious decreased immediately after laser irradiation and following an initial increase on day 3, there was a peak at day 10. The results suggest that a part of collagen molecules is denatured by the heat of laser. There is an effect of stimulating collagen synthesis after laser welding with parameters used in this study.

  6. Factor XIII-A subunit Val34Leu polymorphism in fatal hemorrhagic stroke.

    PubMed

    Antalfi, B; Pongrácz, E; Csiki, Z; Mezei, Z A; Shemirani, A H

    2013-02-01

    Blood coagulation factor XIII (FXIII) plays a key role in the protection of fibrin clot against fibrinolysis, in the cross-linking of fibrin and its mechanical strength. The role of the FXIII-A subunit Val34Leu polymorphism with fatal primary intracerebral hemorrhages (PICH) has not been studied. We evaluated retrospectively the prevalence of this polymorphism in stroke patients with fatal PICH and population control matched for age and gender. The prevalence of this polymorphism was determined for patients with fatal PICH (n = 98, female/male: 41/57) and controls. DNA was obtained from peripheral white blood cells in case of controls and from paraffin-embedded tissue sections in case of fatal PICH. The odds for increasing the risk of PICH against the control group were 5.429, 3.286, and 7.661 for total, female, and male patients, respectively. The Leu34Leu homozygous variant of the FXIII Val34Leu polymorphism significantly increased the risk of fatal PICH stroke in men. PMID:22909010

  7. Structural basis of sequence-specific collagen recognition by SPARC

    PubMed Central

    Hohenester, Erhard; Sasaki, Takako; Giudici, Camilla; Farndale, Richard W.; Bächinger, Hans Peter

    2008-01-01

    Protein interactions with the collagen triple helix play a critical role in collagen fibril formation, cell adhesion, and signaling. However, structural insight into sequence-specific collagen recognition is limited to an integrin-peptide complex. A GVMGFO motif in fibrillar collagens (O denotes 4-hydroxyproline) binds 3 unrelated proteins: von Willebrand factor (VWF), discoidin domain receptor 2 (DDR2), and the extracellular matrix protein SPARC/osteonectin/BM-40. We report the crystal structure at 3.2 Å resolution of human SPARC bound to a triple-helical 33-residue peptide harboring the promiscuous GVMGFO motif. SPARC recognizes the GVMGFO motifs of the middle and trailing collagen chains, burying a total of 720 Å2 of solvent-accessible collagen surface. SPARC binding does not distort the canonical triple helix of the collagen peptide. In contrast, a critical loop in SPARC is substantially remodelled upon collagen binding, creating a deep pocket that accommodates the phenylalanine residue of the trailing collagen chain (“Phe pocket”). This highly restrictive specificity pocket is shared with the collagen-binding integrin I-domains but differs strikingly from the shallow collagen-binding grooves of the platelet receptor glycoprotein VI and microbial adhesins. We speculate that binding of the GVMGFO motif to VWF and DDR2 also results in structural changes and the formation of a Phe pocket. PMID:19011090

  8. Outdoor Play and Play Equipment.

    ERIC Educational Resources Information Center

    Naylor, Heather

    1985-01-01

    Discusses aspects of the play environment and its effect on children's play behavior. Indoor and outdoor play spaces are considered along with factors affecting the use of outdoor environments for play. Children's preferences for different outdoor play environments and for various play structures are explored. Guides for choosing play equipment…

  9. Enigmatic insight into collagen.

    PubMed

    Deshmukh, Shrutal Narendra; Dive, Alka M; Moharil, Rohit; Munde, Prashant

    2016-01-01

    Collagen is a unique, triple helical molecule which forms the major part of extracellular matrix. It is the most abundant protein in the human body, representing 30% of its dry weight. It is the fibrous structural protein that makes up the white fibers (collagen fibers) of skin, tendons, bones, cartilage and all other connective tissues. Collagens are not only essential for the mechanical resistance and resilience of multicellular organisms, but are also signaling molecules defining cellular shape and behavior. The human body has at least 16 types of collagen, but the most prominent types are I, II and III. Collagens are produced by several cell types and are distinguishable by their molecular compositions, morphologic characteristics, distribution, functions and pathogenesis. This is the major fibrous glycoprotein present in the extracellular matrix and in connective tissue and helps in maintaining the structural integrity of these tissues. It has a triple helical structure. Various studies have proved that mutations that modify folding of the triple helix result in identifiable genetic disorders. Collagen diseases share certain similarities with autoimmune diseases, because autoantibodies specific to each collagen disease are produced. Therefore, this review highlights the role of collagen in normal health and also the disorders associated with structural and functional defects in collagen. PMID:27601823

  10. Collagen and gelatin.

    PubMed

    Liu, Dasong; Nikoo, Mehdi; Boran, Gökhan; Zhou, Peng; Regenstein, Joe M

    2015-01-01

    Collagen and gelatin have been widely used in the food, pharmaceutical, and cosmetic industries due to their excellent biocompatibility, easy biodegradability, and weak antigenicity. Fish collagen and gelatin are of renewed interest, owing to the safety and religious concerns of their mammalian counterparts. The structure of collagen has been studied using various modern technologies, and interpretation of the raw data should be done with caution. The structure of collagen may vary with sources and seasons, which may affect its applications and optimal extraction conditions. Numerous studies have investigated the bioactivities and biological effects of collagen, gelatin, and their hydrolysis peptides, using both in vitro and in vivo assay models. In addition to their established nutritional value as a protein source, collagen and collagen-derived products may exert various potential biological activities on cells in the extracellular matrix through the corresponding food-derived peptides after ingestion, and this might justify their applications in dietary supplements and pharmaceutical preparations. Moreover, an increasing number of novel applications have been found for collagen and gelatin. Therefore, this review covers the current understanding of the structure, bioactivities, and biological effects of collagen, gelatin, and gelatin hydrolysates as well as their most recent applications. PMID:25884286

  11. Enigmatic insight into collagen

    PubMed Central

    Deshmukh, Shrutal Narendra; Dive, Alka M; Moharil, Rohit; Munde, Prashant

    2016-01-01

    Collagen is a unique, triple helical molecule which forms the major part of extracellular matrix. It is the most abundant protein in the human body, representing 30% of its dry weight. It is the fibrous structural protein that makes up the white fibers (collagen fibers) of skin, tendons, bones, cartilage and all other connective tissues. Collagens are not only essential for the mechanical resistance and resilience of multicellular organisms, but are also signaling molecules defining cellular shape and behavior. The human body has at least 16 types of collagen, but the most prominent types are I, II and III. Collagens are produced by several cell types and are distinguishable by their molecular compositions, morphologic characteristics, distribution, functions and pathogenesis. This is the major fibrous glycoprotein present in the extracellular matrix and in connective tissue and helps in maintaining the structural integrity of these tissues. It has a triple helical structure. Various studies have proved that mutations that modify folding of the triple helix result in identifiable genetic disorders. Collagen diseases share certain similarities with autoimmune diseases, because autoantibodies specific to each collagen disease are produced. Therefore, this review highlights the role of collagen in normal health and also the disorders associated with structural and functional defects in collagen. PMID:27601823

  12. Genetic variants of coagulation factor XIII, postmenopausal estrogen therapy, and risk of nonfatal myocardial infarction.

    PubMed

    Reiner, Alexander P; Heckbert, Susan R; Vos, Hans L; Ariëns, Robert A S; Lemaitre, Rozenn N; Smith, Nicholas L; Lumley, Thomas; Rea, Thomas D; Hindorff, Lucia A; Schellenbaum, Gina D; Rosendaal, Frits R; Siscovick, David S; Psaty, Bruce M

    2003-07-01

    We hypothesized that possession of either of 2 functional coagulation factor XIII polymorphisms, one within subunit A (Val34Leu) and one within subunit B (His95Arg), might modulate the prothrombotic effects of estrogen and help to explain the variation in incidence of arterial thrombotic events among postmenopausal women using hormone replacement therapy. In a population-based case-control study of 955 postmenopausal women, we assessed the associations of factor XIII genotypes and their interactions with estrogen therapy on risk of nonfatal myocardial infarction (MI). The presence of the factor XIIIA Leu34 allele was associated with a reduced risk of MI (odds ratio [OR] = 0.70, 95% confidence interval [95% CI] = 0.51-0.95). The presence of the factor XIIIB Arg95 allele had little association with MI risk. Neither factor XIII polymorphism alone significantly modified the association between the risk of MI and current estrogen use. In exploratory analyses, however, there was a significant factor XIII subunit gene-gene interaction. Compared to women homozygous for both common factor XIII alleles, the Arg95 variant was associated with a reduced risk of MI in the presence of the Leu34 variant (OR = 0.36, 95% CI = 0.17-0.75) but not in the absence of the Leu34 variant (OR = 1.11, 95% CI = 0.69-1.79). Moreover, among women who had at least 2 copies of the variant factor XIII alleles and were current estrogen users, the risk of MI was reduced by 70% relative to estrogen nonusers with fewer than 2 factor XIII variant alleles (P value for interaction =.03). If confirmed, these findings may permit a better assessment of the cardiovascular risks and benefits associated with postmenopausal estrogen therapy. PMID:12456499

  13. New Play.

    ERIC Educational Resources Information Center

    Lersten, Kenneth C.

    There have been many theories and hypotheses about play, one of which is the equation of play with "transcendence." Play may have the ingredients to allow us to transcend and, for a moment, remythologize life. There have been recent authors who have given play the status of theology, indicating that play contains elements also found in religion.…

  14. Playful Gaming.

    ERIC Educational Resources Information Center

    Makedon, Alexander

    A philosophical analysis of play and games is undertaken in this paper. Playful gaming, which is shown to be a synthesis of play and games, is utilized as a category for undertaking the examination of play and games. The significance of playful gaming to education is demonstrated through analyses of Plato's, Dewey's, Sartre's, and Marcuse's…

  15. Collagen: Biochemistry, biomechanics, biotechnology

    SciTech Connect

    Nimni, M.E.

    1988-01-01

    This book is an up-to-date reference for new ideas, information, and concepts in collagen research. The first volume emphasizes the relationship between the molecular structure and function of collagen, including descriptions of collagen types which exist in tissues as well as how these molecules organize into fibrils and the nature of the chemical crosslinks which stabilize them. In Volume II the biomechanical behavior of various specialized tissues, abnormal accumulation of collagen in the form of scars of fibrous infiltration are examined/and wound healing, tissue regulation and repair are covered in detail. Volume III explores the increasing application of collagen technology to the field of bioprosthesis, including the production of heart valve bioprosthesis, blood vessels, ligament substitutes, and bone substitutes.

  16. Oxidative damage to collagen.

    PubMed

    Monboisse, J C; Borel, J P

    1992-01-01

    Extracellular matrix molecules, such as collagens, are good targets for oxygen free radicals. Collagen is the only protein susceptible to fragmentation by superoxide anion as demonstrated by the liberation of small 4-hydroxyproline-containing-peptides. It seems likely that hydroxyl radicals in the presence of oxygen cleave collagen into small peptides, and the cleavage seems to be specific to proline or 4-hydroxyproline residues. Hydroxyl radicals in the absence of oxygen or hypochlorous acid do not induce fragmentation of collagen molecules, but they trigger a polymerization of collagen through the formation of new cross-links such as dityrosine or disulfure bridges. Moreover, these cross-links can not explain the totality of high molecular weight components generated under these experimental conditions, and the nature of new cross-links induced by hydroxyl radicals or hypochlorous acid remains unclear. PMID:1333311

  17. Collagen coated tantalum substrate for cell proliferation.

    PubMed

    Li, Yinli; Zhang, Shuai; Guo, Lijun; Dong, Mingdong; Liu, Bo; Mamdouh, Wael

    2012-06-15

    The extracellular matrix (ECM) plays a key role in cell culture in various physiological and pathological processes in the field of tissue engineering. Recently, the type I collagen ECM has been widely utilized in vitro model systems for the attachment of many different cell lines since it has multi-functions in human tissues. For example it accounts for 6% of the weight of strong, tendinous muscles. In this paper, we reported a new material by coating tantalum (Ta), one highly biocompatible metal, with type I collagen fibrils. The morphology of the new material was studied by high resolution atomic force microscope. It was shown that the adhesion force between type I collagen fibrils network and Ta was strong enough to overcome surface defects. A possible way to explain the phenomenon is that the longitudinal periodicity of collagen fibrils matches the grain size of the Ta domains, which results in increase of the physical adsorption contact area, thereby inducing the dramatic adhesion enhancement between collagen fibrils and Ta. The obtained material was then employed as a template for cell proliferation. Although the surface of this template is more hydrophobic by comparison with the bare Ta surface, the cells on this material were successfully incubated, indicating that the collagen coated Ta might be used as the buffer layer for proliferating cells in hydrophobic biomaterials. PMID:22494669

  18. Type VI Collagen Regulates Dermal Matrix Assembly and Fibroblast Motility.

    PubMed

    Theocharidis, Georgios; Drymoussi, Zoe; Kao, Alexander P; Barber, Asa H; Lee, David A; Braun, Kristin M; Connelly, John T

    2016-01-01

    Type VI collagen is a nonfibrillar collagen expressed in many connective tissues and implicated in extracellular matrix (ECM) organization. We hypothesized that type VI collagen regulates matrix assembly and cell function within the dermis of the skin. In the present study we examined the expression pattern of type VI collagen in normal and wounded skin and investigated its specific function in new matrix deposition by human dermal fibroblasts. Type VI collagen was expressed throughout the dermis of intact human skin, at the expanding margins of human keloid samples, and in the granulation tissue of newly deposited ECM in a mouse model of wound healing. Generation of cell-derived matrices (CDMs) by human dermal fibroblasts with stable knockdown of COL6A1 revealed that type VI collagen-deficient matrices were significantly thinner and contained more aligned, thicker, and widely spaced fibers than CDMs produced by normal fibroblasts. In addition, there was significantly less total collagen and sulfated proteoglycans present in the type VI collagen-depleted matrices. Normal fibroblasts cultured on de-cellularized CDMs lacking type VI collagen displayed increased cell spreading, migration speed, and persistence. Taken together, these findings indicate that type VI collagen is a key regulator of dermal matrix assembly, composition, and fibroblast behavior and may play an important role in wound healing and tissue regeneration. PMID:26763426

  19. Collagen XXVII Organises the Pericellular Matrix in the Growth Plate

    PubMed Central

    Plumb, Darren A.; Ferrara, Laila; Torbica, Tanja; Knowles, Lynnette; Mironov, Aleksandr; Kadler, Karl E.; Briggs, Michael D.; Boot-Handford, Raymond P.

    2011-01-01

    In order to characterise the function of the novel fibrillar type XXVII collagen, a series of mice expressing mutant forms of the collagen were investigated. Mice harboring a glycine to cysteine substitution in the collagenous domain were phenotypically normal when heterozygote and displayed a mild disruption of growth plate architecture in the homozygous state. Mice expressing an 87 amino acid deletion in the collagenous domain of collagen XXVII were phenotypically normal as heterozygotes whereas homozygotes exhibited a severe chondrodysplasia and died perinatally from a lung defect. Animals expressing the 87 amino acid deletion targeted specifically to cartilage were viable but severely dwarfed. The pericellular matrix of proliferative chondrocytes was disrupted and the proliferative cells exhibited a decreased tendency to flatten and form vertical columns. Collagen XXVII plays an important structural role in the pericellular extracellular matrix of the growth plate and is required for the organisation of the proliferative zone. PMID:22206015

  20. Guidelines for laboratory diagnosis of factor XIII deficiency.

    PubMed

    Dorgalaleh, Akbar; Tabibian, Shadi; Hosseini, Soudabeh; Shamsizadeh, Morteza

    2016-06-01

    Factor XIII (FXIII) deficiency is an extremely rare hemorrhagic disorder with an approximate worldwide incidence of one per two million. With current tests, diagnosis of this disease can be made more precisely. However, factors such as the number of patients with FXIII deficiency (FXIIID), available diagnostic coagulation tests and the number of molecular studies have affected the diagnosis of FXIIID in different parts of the world. Various laboratory approaches can be used, including screening and diagnosis of the disorder in countries with a relatively high rate of FXIIID and recurrent mutation(s) with a simple polymerase chain reaction-restriction fragment length polymorphism analysis or polymerase chain reaction-sequencing for detection of one or a few specific mutations. In other countries, two different laboratory approaches can be used, depending on available coagulation tests. In less-equipped coagulation laboratories, the clot solubility test remains the only diagnostic test for FXIIID. Even in these countries, at least one referral laboratory should perform FXIII activity and, if possible, confirmation of FXIIID by molecular analysis. In countries with well equipped coagulation laboratories, FXIII activity should be used to screen suspected FXIIID patients; more specific tests such as molecular analysis should be used for confirmation. This study suggests a simple, reliable and flexible algorithm for early diagnosis of FXIIID, and may, with one-time diagnosis of FXIIID, reduce the rate of morbidity and mortality in patients with the disorder. PMID:26588445

  1. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of...

  2. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of...

  3. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of...

  4. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of...

  5. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of...

  6. Mapping and Exploring the Collagen-I Proteostasis Network.

    PubMed

    DiChiara, Andrew S; Taylor, Rebecca J; Wong, Madeline Y; Doan, Ngoc-Duc; Rosario, Amanda M Del; Shoulders, Matthew D

    2016-05-20

    Collagen-I is the most abundant protein in the human body, yet our understanding of how the endoplasmic reticulum regulates collagen-I proteostasis (folding, quality control, and secretion) remains immature. Of particular importance, interactomic studies to map the collagen-I proteostasis network have never been performed. Such studies would provide insight into mechanisms of collagen-I folding and misfolding in cells, an area that is particularly important owing to the prominence of the collagen misfolding-related diseases. Here, we overcome key roadblocks to progress in this area by generating stable fibrosarcoma cells that inducibly express properly folded and modified collagen-I strands tagged with distinctive antibody epitopes. Selective immunoprecipitation of collagen-I from these cells integrated with quantitative mass spectrometry-based proteomics permits the first mapping of the collagen-I proteostasis network. Biochemical validation of the resulting map leads to the assignment of numerous new players in collagen-I proteostasis, and the unanticipated discovery of apparent aspartyl-hydroxylation as a new post-translational modification in the N-propeptide of collagen-I. Furthermore, quantitative analyses reveal that Erp29, an abundant endoplasmic reticulum proteostasis machinery component with few known functions, plays a key role in collagen-I retention under ascorbate-deficient conditions. In summary, the work here provides fresh insights into the molecular mechanisms of collagen-I proteostasis, yielding a detailed roadmap for future investigations. Straightforward adaptations of the cellular platform developed will also enable hypothesis-driven, comparative research on the likely distinctive proteostasis mechanisms engaged by normal and disease-causing, misfolding collagen-I variants, potentially motivating new therapeutic strategies for currently incurable collagenopathies. PMID:26848503

  7. Clinical studies on plasma fibronectin and factor XIII; with special reference to hyperlipoproteinemia.

    PubMed

    Cucuianu, M; Rus, H G; Cristea, A; Niculescu, F; Bedeleanu, D; Poruţiu, D; Roman, S

    1985-04-30

    When compared to age-matched normal weight normolipidemic control subjects, plasma factor XIII, plasma fibronectin and serum cholinesterase levels were found to be markedly decreased in patients with decompensated cirrhosis of the liver, not significantly changed in hyperlipoproteinemia type IIa (heterozygous subjects) and increased in hypertriglyceridemic subjects (type IIb and IV) as well as in hyperlipidemic nephrotic patients. A possible accelerated hepatic synthesis of certain plasma proteins including factor XIII and fibronectin in patients with the nephrotic syndrome as well as in endogenous hypertriglyceridemia is envisaged. It is also considered that mural thrombi, richer in factor XIII and fibronectin, would be more resistant to fibrinolysis and more readily attached to subendothelial structures. PMID:3922652

  8. Collagenous Colitis and Spondylarthropathy

    PubMed Central

    Ben Abdelghani, Kaouther; Sahli, Hana; Souabni, Leila; Chekili, Selma; Belhadj, Salwa; Kassab, Selma; Laatar, Ahmed; Zakraoui, Leith

    2012-01-01

    Collagenous colitis is a recent cause of chronic diarrhea. Cooccurrence with spondylarthropathy is rare. We describe two cases: one man and one woman of 33 and 20 years old were suffering from spondylarthropathy. They then developed collagenous colitis, 4 and 14 years after the onset of spondylarthropathy. The diagnosis was based on histological features. A sicca syndrome and vitiligo were observed with the female case. The presence of colitis leads to therapeutic problems. This association suggests a systemic kind of rheumatic disease of collagenous colitis. PMID:22701491

  9. Increased expression of factor XIII-A in patients with chronic rhinosinusitis with nasal polyps

    PubMed Central

    Takabayashi, Tetsuji; Kato, Atsushi; Peters, Anju T.; Hulse, Kathryn E.; Suh, Lydia A.; Carter, Roderick; Norton, James; Grammer, Leslie C.; Tan, Bruce K.; Chandra, Rakesh K.; Conley, David B.; Kern, Robert C.; Fujieda, Shigeharu; Schleimer, Robert P.

    2013-01-01

    Background Profound edema or formation of a pseudocyst containing plasma proteins is a prominent characteristic of Nasal polyps (NP). However, the mechanisms underlying NP retention of plasma proteins in the submucosa remain unclear. Recently, we reported that impairment of fibrinolysis causes excessive fibrin deposition in NP and this might be involved in retention of plasma proteins. Although the coagulation cascade plays a critical role in fibrin clot formation at extravascular sites, the expression and role of coagulation factors in NP remain unclear. Objective The objective of this study was to investigate the expression of coagulation factors in patients with chronic rhinosinusitis (CRS). Methods Sinonasal tissues were collected from patients with CRS and control subjects. We assayed mRNA for factor XIII-A (FXIII-A) by using real-time PCR and measured FXIII-A protein by means of ELISA, immunohistochemistry and immunofluorescence. Results FXIII-A mRNA levels were significantly increased in NP from patients with CRS with nasal polyps (CRSwNP; P < .001) compared with uncinate tissue from patients with CRS or control subjects. Similarly, FXIII-A protein levels were increased in NP. Immunofluorescence analysis revealed FXIII-A expression in inflammatory cells, and FXIII-A+ cell numbers were significantly increased in NP. Most FXIII-A staining was observed within CD68+/CD163+ M2 macrophages in NP. Levels of FXIII-A correlated with markers of M2 macrophages, suggesting that M2 macrophages are major FXIIIA producing cells in NP. Conclusion Overproduction of FXIII-A by M2 macrophages might contribute to the excessive fibrin deposition in the submucosa of NP, which might contribute to the tissue remodeling and pathogenesis of CRSwNP. PMID:23541322

  10. Extreme Ultraviolet Emission Lines of Iron Fe XI-XIII

    NASA Astrophysics Data System (ADS)

    Lepson, Jaan; Beiersdorfer, P.; Brown, G. V.; Liedahl, D. A.; Brickhouse, N. S.; Dupree, A. K.

    2013-04-01

    The extreme ultraviolet (EUV) spectral region (ca. 20--300 Å) is rich in emission lines from low- to mid-Z ions, particularly from the middle charge states of iron. Many of these emission lines are important diagnostics for astrophysical plasmas, providing information on properties such as elemental abundance, temperature, density, and even magnetic field strength. In recent years, strides have been made to understand the complexity of the atomic levels of the ions that emit the lines that contribute to the richness of the EUV region. Laboratory measurements have been made to verify and benchmark the lines. Here, we present laboratory measurements of Fe XI, Fe XII, and Fe XIII between 40-140 Å. The measurements were made at the Lawrence Livermore electron beam ion trap (EBIT) facility, which has been optimized for laboratory astrophysics, and which allows us to select specific charge states of iron to help line identification. We also present new calculations by the Hebrew University - Lawrence Livermore Atomic Code (HULLAC), which we also utilized for line identification. We found that HULLAC does a creditable job of reproducing the forest of lines we observed in the EBIT spectra, although line positions are in need of adjustment, and line intensities often differed from those observed. We identify or confirm a number of new lines for these charge states. This work was supported by the NASA Solar and Heliospheric Program under Contract NNH10AN31I and the DOE General Plasma Science program. Work was performed in part under the auspices of the Department of Energy by Lawrence Livermore National Laboratory under Contract DEAC52-07NA27344.

  11. Nanomechanics of collagen microfibrils

    PubMed Central

    Vesentini, Simone; Redaelli, Alberto; Gautieri, Alfonso

    2013-01-01

    Summary Collagen constitutes one third of the human proteome, providing mechanical stability, elasticity and strength to organisms and is thus the prime construction material in biology. Collagen is also the dominating material in the extracellular matrix where its stiffness controls cell differentiation, growth and pathology. We use atomistic-based hierarchical multiscale modeling to describe this complex biological material from the bottom up. This includes the use and development of large-scale computational modeling tools to investigate several aspects related to collagen-based tissues, including source of visco-elasticity and deformation mechanisms at the nanoscale level. The key innovation of this research is that until now, collagen materials have primarily been described at macroscopic scales, without explicitly understanding the mechanical contributions at the molecular and fibrillar levels. The major impact of this research will be the development of fundamental models of collagenous tissues, important to the design of new scaffolding biomaterials for regenerative medicine as well as for the understanding of collagen-related diseases. PMID:23885342

  12. Tumor suppression by collagen XV is independent of the restin domain

    PubMed Central

    Mutolo, Michael J; Morris, Kirsten J; Leir, Shih-Hsing; Caffrey, Thomas C.; Lewandowska, Marzena A.; Hollingsworth, Michael A; Harris, Ann

    2012-01-01

    Non-fibrillar collagen XV is a chondroitin sulphate modified glycoprotein that is associated with the basement membrane zone in many tissues. Its precise functions remain to be fully elucidated though it clearly plays a critical role in the structural integrity of the extracellular matrix. Loss of collagen XV from the basement membrane zone precedes invasion of a number of tumor types and we previously showed that collagen XV functions as a dose-dependent suppressor of tumorigenicity in cervical carcinoma cells. The carboxyl terminus of another non-fibrillar collagen (XVIII) is cleaved to produce endostatin, which has anti-angiogenic effects and thus may act as a tumor suppressor in vivo. Since collagen XV has structural similarity with collagen XVIII, its C-terminal restin domain could confer tumor suppressive functions on the molecule, though our previous data did not support this. We now show that expression of collagen XV enhances the adhesion of cervical carcinoma cells to collagen I in vitro as does the N-terminus and collagenous regions of collagen XV, but not the restin domain. Destruction of a cysteine residue in the collagenous region that is critical for intermolecular interactions of collagen XV abolished the enhanced adhesion to collagen I. Finally, we demonstrate that unlike full length collagen XV, expression of the restin domain alone does not suppress tumorigenicity of cervical carcinoma cells in vivo; hence, this process is dependent on functions and interactions of other parts of the protein. PMID:22531369

  13. Photo-active collagen systems with controlled triple helix architecture

    PubMed Central

    Tronci, Giuseppe; Russell, Stephen J.; Wood, David J.

    2016-01-01

    The design of photo-active collagen systems is presented as a basis for establishing biomimetic materials with varied network architecture and programmable macroscopic properties. Following in-house isolation of type I collagen, reaction with vinyl-bearing compounds of varied backbone rigidity, i.e. 4-vinylbenzyl chloride (4VBC) and glycidyl methacrylate (GMA), was carried out. TNBS colorimetric assay, 1H-NMR and ATR-FTIR confirmed covalent and tunable functionalization of collagen lysines. Depending on the type and extent of functionalization, controlled stability and thermal denaturation of triple helices were observed via circular dichroism (CD), whereby the hydrogen-bonding capability of introduced moieties was shown to play a major role. Full gel formation was observed following photo-activation of functionalized collagen solutions. The presence of a covalent network only slightly affected collagen triple helix conformation (as observed by WAXS and ATR-FTIR), confirming the structural organization of functionalized collagen precursors. Photo-activated hydrogels demonstrated an increased denaturation temperature (DSC) with respect to native collagen, suggesting that the formation of the covalent network successfully stabilized collagen triple helices. Moreover, biocompatibility and mechanical competence of obtained hydrogels were successfully demonstrated under physiologically-relevant conditions. These results demonstrate that this novel synthetic approach enabled the formation of biocompatible collagen systems with defined network architecture and programmable macroscopic properties, which can only partially be obtained with current synthetic methods.

  14. Adult Play.

    ERIC Educational Resources Information Center

    Charles, John M.

    In its broadest context, play can be interpreted as any pleasurable use of discretionary time. Playfulness is an intrinsic feature of being human, and should be viewed in the light of a total lifestyle, not as an occurrence in an isolated time of life. Adult play appears to be an indefinable and controversial concept. A holistic approach should be…

  15. Wanna Play?

    ERIC Educational Resources Information Center

    Chenfeld, Mimi Brodsky

    2006-01-01

    In this article, the author talks about the importance of play in the lives of children and describes how games and imaginative play contribute to the development of children. From her decades-old collection of countless incidents demonstrating children's love for self-directed, informal, imaginative play, the author shares three incidents that…

  16. City Play.

    ERIC Educational Resources Information Center

    Dargan, Amanda; Zeitlin, Steve

    2000-01-01

    Today, fewer city blocks preserve the confidence of lifestyle and urban geography that sustain traditional games and outdoor play. Large groups of children choosing sides and organizing Red Rover games are no longer commonplace. Teachers must encourage free play; urban planners must build cities that are safe play havens. (MLH)

  17. Type V collagen controls the initiation of collagen fibril assembly.

    PubMed

    Wenstrup, Richard J; Florer, Jane B; Brunskill, Eric W; Bell, Sheila M; Chervoneva, Inna; Birk, David E

    2004-12-17

    Vertebrate collagen fibrils are heterotypically composed of a quantitatively major and minor fibril collagen. In non-cartilaginous tissues, type I collagen accounts for the majority of the collagen mass, and collagen type V, the functions of which are poorly understood, is a minor component. Type V collagen has been implicated in the regulation of fibril diameter, and we reported recently preliminary evidence that type V collagen is required for collagen fibril nucleation (Wenstrup, R. J., Florer, J. B., Cole, W. G., Willing, M. C., and Birk, D. E. (2004) J. Cell. Biochem. 92, 113-124). The purpose of this study was to define the roles of type V collagen in the regulation of collagen fibrillogenesis and matrix assembly. Mouse embryos completely deficient in pro-alpha1(V) chains were created by homologous recombination. The col5a1-/- animals die in early embryogenesis, at approximately embryonic day 10. The type V collagen-deficient mice demonstrate a virtual lack of collagen fibril formation. In contrast, the col5a1+/- animals are viable. The reduced type V collagen content is associated with a 50% reduction in fibril number and dermal collagen content. In addition, relatively normal, cylindrical fibrils are assembled with a second population of large, structurally abnormal collagen fibrils. The structural properties of the abnormal matrix are decreased relative to the wild type control animals. These data indicate a central role for the evolutionary, ancient type V collagen in the regulation of fibrillogenesis. The complete dependence of fibril formation on type V collagen is indicative of the critical role of the latter in early fibril initiation. In addition, this fibril collagen is important in the determination of fibril structure and matrix organization. PMID:15383546

  18. Expression of Functional Human Coagulation Factor XIII A-domain in Plant Cell Suspensions and Whole Plants

    SciTech Connect

    Gao, Johnway; Hooker, Brian S.; Anderson, Daniel B.

    2004-09-01

    Coagulation factor XIII, a zymogen present in blood as a tetramer (A2B2) of A- and B-domains, is one of the components of many ''wound sealants'' which are proposed for use or currently in use as effective hemostatic agents, sealants and tissue adhesives in surgery. After activation by ?-thrombin cleavage, coagulation factor XIII A-domain, a transglutaminase, is formed and catalyzes the covalent crosslinking of the ?- and ?-chains of linear fibrin to form homopolymers, which can quickly stop bleeding. We have successfully expressed the A-domain of factor XIII in both plant cell cultures and whole plants. Transgenic plant cell culture allows a rapid method for testing production feasibility while expression in whole plants demonstrates an economic production system for recombinant human plasma-based proteins. The expressed factor XIII A-domain had a similar size as that of human plasma-derived factor XIII. Crude plant extract containing recombinant factor XIII A-domain showed transglutaminase activity with monodansylcadaverine and casein as substrates and crosslinking activity in the presence of linear fibrin. The expression of factor XIII A-domain was not affected by plant leaf position.

  19. Bleeding risk and reproductive capacity among patients with factor XIII deficiency: a case presentation and review of the literature.

    PubMed

    Burrows, R F; Ray, J G; Burrows, E A

    2000-02-01

    Factor XIII deficiency is an uncommon, inherited bleeding disorder that usually manifests in infancy or early childhood, involving both boys and girls. We present the case of a woman who had experienced two previous intracranial bleeding events, and was treated before and during her current pregnancy with factor XIII concentrate. Her pregnancy was successful, and she experienced an uncomplicated vaginal delivery. To better understand the issues surrounding bleeding, reproductive capacity, and management of factor XIII deficiency during pregnancy, we conducted a systematic literature review using MEDLINE from 1966 to December 1998. We also examined the bibliographic references from all articles, and included all cases, case reports, or case series of patients with factor XIII deficiency. We retrieved data on 117 patients from 37 articles, the majority of which had type II deficiency. Among untreated patients with type II factor XIII deficiency, the literature suggests an elevated mortality rate due to uncontrolled bleeding and intracranial hemorrhage. Because of its high degree of efficacy, the evidence supports the use of life long prophylactic therapy with at least monthly infusions of factor XIII concentrate, including during pregnancy. The opinion that women with type II factor XIII deficiency have inevitable recurrent abortions, or that men are sterile, is not well substantiated. No data were found on whether treatment alters male reproductive capacity. A policy of universal factor XIII replacement, starting in childhood, will likely enable more patients to attain reproductive status. The development of an international data registry would optimally address both bleeding risk and reproductive capacity among patients with factor XIII deficiency. PMID:10674253

  20. 25 CFR 36.40 - Standard XIII-Library/media program.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Standard XIII-Library/media program. 36.40 Section 36.40... § 36.40 Standard XIII—Library/media program. (a) Each school shall provide a library/media program... developed by a library committee in collaboration with the librarian and be approved by the school...

  1. Excitation rate coefficient measurements of Cu xiii and Cu xvii ions

    NASA Astrophysics Data System (ADS)

    Datla, R. U.; Roberts, J. R.; Rowan, W. L.; Mann, J. B.

    1986-12-01

    The absolute excitation rate coefficients for Cu xiii and Cu xvii optically allowed transitions have been measured using the Texas Experimental Tokamak (TEXT) tokamak. Cu is injected by the laser-ablation method at a time when the plasma has attained steady-state temperature and density profiles. The absolute intensities of the magnetic-dipole-forbidden transitions within the Cu xiii 3s23p5 and the Cu xvii 3s23p ground configurations are measured. The intensities of optically allowed vacuum-ultraviolet lines within the 3p43d-3p5 transition array of Cu xiii and within the 3d-3p transition array of Cu xvii are measured with a 2.2-m grazing incidence spectrometer. This instrument is radiometrically calibrated in situ by using the branching-ratio technique. The absolute excitation rate coefficients are deduced from these measurements, assuming coronal equilibrium, optically thin line emission, and statistical population within the ground configuration. The experimental rate coefficients for these transition arrays are found to be 2.84×10-8 cm3 s-1 for Cu xiii at an electron temperature of 127 eV and 3.5×10-8 cm3 s-1 for Cu xvii at an electron temperature of 240 eV. These results are in good agreement with excitation rate coefficients computed in a distorted-wave approximation. The estimated uncertainty in the experimental values is +/-70%.

  2. 25 CFR 36.40 - Standard XIII-Library/media program.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Standard XIII-Library/media program. 36.40 Section 36.40... § 36.40 Standard XIII—Library/media program. (a) Each school shall provide a library/media program... developed by a library committee in collaboration with the librarian and be approved by the school...

  3. 25 CFR 36.40 - Standard XIII-Library/media program.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Standard XIII-Library/media program. 36.40 Section 36.40... § 36.40 Standard XIII—Library/media program. (a) Each school shall provide a library/media program... developed by a library committee in collaboration with the librarian and be approved by the school...

  4. 25 CFR 36.40 - Standard XIII-Library/media program.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Standard XIII-Library/media program. 36.40 Section 36.40... § 36.40 Standard XIII—Library/media program. (a) Each school shall provide a library/media program... developed by a library committee in collaboration with the librarian and be approved by the school...

  5. 25 CFR 36.40 - Standard XIII-Library/media program.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Standard XIII-Library/media program. 36.40 Section 36.40... § 36.40 Standard XIII—Library/media program. (a) Each school shall provide a library/media program... developed by a library committee in collaboration with the librarian and be approved by the school...

  6. Collagen type VI myopathies.

    PubMed

    Bushby, Kate M D; Collins, James; Hicks, Debbie

    2014-01-01

    Mutations in each of the three collagen VI genes COL6A1, COL6A2 and COL6A3 cause two main types of muscle disorders: Ullrich congenital muscular dystrophy, a severe phenotype, and a mild to moderate phenotype Bethlem myopathy. Recently, two additional phenotypes, including a limb-girdle muscular dystrophy phenotype and an autosomal recessive myosclerosis reported in one family with mutations in COL6A2 have been reported. Collagen VI is an important component of the extracellular matrix which forms a microfibrillar network that is found in close association with the cell and surrounding basement membrane. Collagen VI is also found in the interstitial space of many tissues including muscle, tendon, skin, cartilage, and intervertebral discs. Thus, collagen VI mutations result in disorders with combined muscle and connective tissue involvement, including weakness, joint laxity and contractures, and abnormal skin findings.In this review we highlight the four recognized clinical phenotypes of collagen VI related - myopathies; Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM), autosomal dominant limb-girdle muscular dystrophy phenotype and autosomal recessive myosclerosis. We discuss the diagnostic criteria of these disorders, the molecular pathogenesis, genetics, treatment, and related disorders. PMID:24443028

  7. EDITORIAL: XIII Mexican Workshop on Particles and Fields

    NASA Astrophysics Data System (ADS)

    Barranco, Juan; Contreras, Guillermo; Delepine, David; Napsuciale, Mauro

    2012-08-01

    Juan Barranco Physics Department, Guanajuato University, Loma del Bosque 103, col. Loma del Campestre, 37150, Leon (Mexico) jbarranc@fisica.ugto.mx Guillermo Contreras Departamento de Fisica Aplicada Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Merida (Mexico) jgcn@mda.cinvestav.mx David Delepine Physics Department, Guanajuato University, Loma del Bosque 103, col. Loma del Campestre, 37150, Leon (Mexico) delepine@fisica.ugto.mx Mauro Napsuciale Physics Department, Guanajuato University, Loma del Bosque 103, col. Loma del Campestre, 37150, Leon (Mexico) mauro@fisica.ugto.mx The XIII Mexican Workshop on Particles and Fields (MWPF) took place from 20-26 October 2011, in the city of León, Guanajuato, México. This is a biennial meeting organized by the Division of Particles and Fields of the Mexican Physical Society designed to gather specialists in different areas of high energy physics to discuss the latest developments in the field. The thirteenth edition of this meeting was hosted by the Department of Cultural Studies of Guanajuato University in a nice environment dedicated to the Arts and Culture. The XIII MWPF was organized by three working groups who organized the corresponding sessions around three topics. The first one was Strings, Cosmology, Astroparticles and Physics Beyond the Standard Model. In this category we included: Cosmic Rays, Gamma Ray Bursts, Physics Beyond the Standard Model (theory and experimental searches), Strings and Cosmology. The working group for this topic was formed by Arnulfo Zepeda, Oscar Loaiza, Axel de la Macorra and Myriam Mondragón. The second topic was Hadronic Matter which included Perturbative QCD, Jets and Diffractive Physics, Hadronic Structure, Soft QCD, Hadron Spectroscopy, Heavy Ion Collisions and Soft Physics at Hadron Colliders, Lattice Results and Instrumentation. The working group for this topic was integrated by Wolfgang Bietenholz and Mariana Kirchbach. The third topic was

  8. Pretend play.

    PubMed

    Weisberg, Deena Skolnick

    2015-01-01

    Pretend play is a form of playful behavior that involves nonliteral action. Although on the surface this activity appears to be merely for fun, recent research has discovered that children's pretend play has connections to important cognitive and social skills, such as symbolic thinking, theory of mind, and counterfactual reasoning. The current article first defines pretend play and then reviews the arguments and evidence for these three connections. Pretend play has a nonliteral correspondence to reality, hence pretending may provide children with practice with navigating symbolic relationships, which may strengthen their language skills. Pretend play and theory of mind reasoning share a focus on others' mental states in order to correctly interpret their behavior, hence pretending and theory of mind may be mutually supportive in development. Pretend play and counterfactual reasoning both involve representing nonreal states of affairs, hence pretending may facilitate children's counterfactual abilities. These connections make pretend play an important phenomenon in cognitive science: Studying children's pretend play can provide insight into these other abilities and their developmental trajectories, and thereby into human cognitive architecture and its development. PMID:26263228

  9. Characterization of carbonic anhydrase XIII in the erythrocytes of the Burmese python, Python molurus bivittatus.

    PubMed

    Esbaugh, A J; Secor, S M; Grosell, M

    2015-09-01

    Carbonic anhydrase (CA) is one of the most abundant proteins found in vertebrate erythrocytes with the majority of species expressing a low activity CA I and high activity CA II. However, several phylogenetic gaps remain in our understanding of the expansion of cytoplasmic CA in vertebrate erythrocytes. In particular, very little is known about isoforms from reptiles. The current study sought to characterize the erythrocyte isoforms from two squamate species, Python molurus and Nerodia rhombifer, which was combined with information from recent genome projects to address this important phylogenetic gap. Obtained sequences grouped closely with CA XIII in phylogenetic analyses. CA II mRNA transcripts were also found in erythrocytes, but found at less than half the levels of CA XIII. Structural analysis suggested similar biochemical activity as the respective mammalian isoforms, with CA XIII being a low activity isoform. Biochemical characterization verified that the majority of CA activity in the erythrocytes was due to a high activity CA II-like isoform; however, titration with copper supported the presence of two CA pools. The CA II-like pool accounted for 90 % of the total activity. To assess potential disparate roles of these isoforms a feeding stress was used to up-regulate CO2 excretion pathways. Significant up-regulation of CA II and the anion exchanger was observed; CA XIII was strongly down-regulated. While these results do not provide insight into the role of CA XIII in the erythrocytes, they do suggest that the presence of two isoforms is not simply a case of physiological redundancy. PMID:26005204

  10. Shadow Play

    ERIC Educational Resources Information Center

    Trundle, Kathy Cabe; Hilson, Margilee P.

    2012-01-01

    A bunny rabbit playfully hops across the wall. Then hands realign and fingers shift to make a hawk soar toward the ceiling. Most children have enjoyed the delightful experience of playing with shadow puppets. The authors build on this natural curiosity to help students link shadows to complex astronomical concepts such as seasons. The…

  11. Collagen in organ development

    NASA Technical Reports Server (NTRS)

    Hardman, P.; Spooner, B. S.

    1992-01-01

    It is important to know whether microgravity will adversely affect developmental processes. Collagens are macromolecular structural components of the extracellular matrix (ECM) which may be altered by perturbations in gravity. Interstitial collagens have been shown to be necessary for normal growth and morphogenesis in some embryonic organs, and in the mouse salivary gland, the biosynthetic pattern of these molecules changes during development. Determination of the effects of microgravity on epithelial organ development must be preceded by crucial ground-based studies. These will define control of normal synthesis, secretion, and deposition of ECM macromolecules and the relationship of these processes to morphogenesis.

  12. Interstitial Collagen Catabolism*

    PubMed Central

    Fields, Gregg B.

    2013-01-01

    Interstitial collagen mechanical and biological properties are altered by proteases that catalyze the hydrolysis of the collagen triple-helical structure. Collagenolysis is critical in development and homeostasis but also contributes to numerous pathologies. Mammalian collagenolytic enzymes include matrix metalloproteinases, cathepsin K, and neutrophil elastase, and a variety of invertebrates and pathogens possess collagenolytic enzymes. Components of the mechanism of action for the collagenolytic enzyme MMP-1 have been defined experimentally, and insights into other collagenolytic mechanisms have been provided. Ancillary biomolecules may modulate the action of collagenolytic enzymes. PMID:23430258

  13. Genetic disorders of collagen.

    PubMed Central

    Tsipouras, P; Ramirez, F

    1987-01-01

    Osteogenesis imperfecta, Ehlers-Danlos syndrome, and Marfan syndrome form a group of genetic disorders of connective tissue. These disorders exhibit remarkable clinical heterogeneity which reflects their underlying biochemical and molecular differences. Defects in collagen types I and III have been found in all three syndromes. PMID:3543367

  14. Collagen and injectable fillers.

    PubMed

    Cheng, Jacqueline T; Perkins, Stephen W; Hamilton, Mark M

    2002-02-01

    Soft tissue augmentation of facial rhytids, scars, and deformities is a frequently performed office procedure. This article reviews the available biologic (collagen, Dermalogen, Autologen, Isolagen, autologous fat, Fibrel, hyaluronic acid derivatives, particulate fascia lata, micronized Alloderm) and alloplastic (silicone, Bioplastique, and Artecoll) soft tissue injectable fillers. PMID:11781208

  15. Collagen hydrolysate based collagen/hydroxyapatite composite materials

    NASA Astrophysics Data System (ADS)

    Ficai, Anton; Albu, Madalina Georgiana; Birsan, Mihaela; Sonmez, Maria; Ficai, Denisa; Trandafir, Viorica; Andronescu, Ecaterina

    2013-04-01

    The aim of this study was to study the influence of collagen hydrolysate (HAS) on the formation of ternary collagen-hydrolysate/hydroxyapatite composite materials (COLL-HAS/HA). During the precipitation process of HA, a large amount of brushite is resulted at pH = 7 but, practically pure HA is obtained at pH ⩾ 8. The FTIR data reveal the duplication of the most important collagen absorption bands due to the presence of the collagen hydrolysate. The presence of collagen hydrolysate is beneficial for the management of bone and joint disorders such as osteoarthritis and osteoporosis.

  16. Label-free visualization of collagen in submucosa as a potential diagnostic marker for early detection of colorectal cancer

    NASA Astrophysics Data System (ADS)

    Qiu, Jingting; Yang, Yinghong; Jiang, Weizhong; Feng, Changyin; Chen, Zhifen; Guan, Guoxian; Zhu, Xiaoqin; Zhuo, Shuangmu; Chen, Jianxin

    2014-09-01

    The collagen signature in colorectal submucosa is changed due to remodeling of the extracellular matrix during the malignant process and plays an important role in noninvasive early detection of human colorectal cancer. In this work, multiphoton microscopy (MPM) was used to monitor the changes of collagen in normal colorectal submucosa (NCS) and cancerous colorectal submucosa (CCS). What's more, the collagen content was quantitatively measured. It was found that in CCS the morphology of collagen becomes much looser and the collagen content is significantly reduced compared to NCS. These results suggest that MPM has the ability to provide collagen signature as a potential diagnostic marker for early detection of colorectal cancer.

  17. LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression

    PubMed Central

    Zhang, Yujie; Stefanovic, Branko

    2016-01-01

    Type I collagen is the most abundant structural protein in all vertebrates, but its constitutive rate of synthesis is low due to long half-life of the protein (60–70 days). However, several hundred fold increased production of type I collagen is often seen in reparative or reactive fibrosis. The mechanism which is responsible for this dramatic upregulation is complex, including multiple levels of regulation. However, posttranscriptional regulation evidently plays a predominant role. Posttranscriptional regulation comprises processing, transport, stabilization and translation of mRNAs and is executed by RNA binding proteins. There are about 800 RNA binding proteins, but only one, La ribonucleoprotein domain family member 6 (LARP6), is specifically involved in type I collagen regulation. In the 5′untranslated region (5’UTR) of mRNAs encoding for type I and type III collagens there is an evolutionally conserved stem-loop (SL) structure; this structure is not found in any other mRNA, including any other collagen mRNA. LARP6 binds to the 5′SL in sequence specific manner to regulate stability of collagen mRNAs and their translatability. Here, we will review current understanding of how is LARP6 involved in posttranscriptional regulation of collagen mRNAs. We will also discuss how other proteins recruited by LARP6, including nonmuscle myosin, vimentin, serine threonine kinase receptor associated protein (STRAP), 25 kD FK506 binding protein (FKBP25) and RNA helicase A (RHA), contribute to this process. PMID:27011170

  18. Changes in Scleral Collagen Organization in Murine Chronic Experimental Glaucoma

    PubMed Central

    Pijanka, Jacek K.; Kimball, Elizabeth C.; Pease, Mary E.; Abass, Ahmed; Sorensen, Thomas; Nguyen, Thao D.; Quigley, Harry A.; Boote, Craig

    2014-01-01

    Purpose. The organization of scleral collagen helps to determine the eye's biomechanical response to intraocular pressure (IOP), and may therefore be important in glaucoma. This study provides a quantitative assessment of changes in scleral collagen fibril organization in bead-induced murine experimental glaucoma. Methods. Wide-angle X-ray scattering was used to study the effect of bead-induced glaucoma on posterior scleral collagen organization in one eye of 12 CD1 mice, with untreated fellow eyes serving as controls. Three collagen parameters were measured: the local preferred fibril directions, the degree of collagen anisotropy, and the total fibrillar collagen content. Results. The mouse sclera featured a largely circumferential orientation of fibrillar collagen with respect to the optic nerve head canal. Localized alteration to fibril orientations was evident in the inferior peripapillary sclera of bead-treated eyes. Collagen anisotropy was significantly (P < 0.05) reduced in bead-treated eyes in the superior peripapillary (Treated: 43 ± 8%; Control: 49 ± 6%) and midposterior (Treated: 39 ± 4%; Control: 43 ± 4%) sclera, and in the peripapillary region overall (Treated: 43 ± 6%; Control: 47 ± 3%). No significant differences in total collagen content were found between groups. Conclusions. Spatial changes in collagen fibril anisotropy occur in the posterior sclera of mice with bead-induced chronic IOP elevation and axonal damage. These results support the idea that dynamic changes in scleral form and structure play a role in the development of experimental glaucoma in mice, and potentially in human glaucoma. PMID:25228540

  19. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  20. Playing Teacher.

    ERIC Educational Resources Information Center

    Gilbert, Juan E.

    The acceptance of animation technologies is increasing. Video games, such as Sony PlayStation (SONY, 2002), have become part of the culture for young people from kindergarten through undergraduate school. Animation technologies have been implemented into educational systems in the form of animated pedagogical agents (Johnson, 2000). The research…

  1. Game playing.

    PubMed

    Rosin, Christopher D

    2014-03-01

    Game playing has been a core domain of artificial intelligence research since the beginnings of the field. Game playing provides clearly defined arenas within which computational approaches can be readily compared to human expertise through head-to-head competition and other benchmarks. Game playing research has identified several simple core algorithms that provide successful foundations, with development focused on the challenges of defeating human experts in specific games. Key developments include minimax search in chess, machine learning from self-play in backgammon, and Monte Carlo tree search in Go. These approaches have generalized successfully to additional games. While computers have surpassed human expertise in a wide variety of games, open challenges remain and research focuses on identifying and developing new successful algorithmic foundations. WIREs Cogn Sci 2014, 5:193-205. doi: 10.1002/wcs.1278 CONFLICT OF INTEREST: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:26304308

  2. Sweet Play

    ERIC Educational Resources Information Center

    Leung, Shuk-kwan S.; Lo, Jane-Jane

    2010-01-01

    This article features Sweet play math, a "math by the month" activity that involves decorating and making sugar cubes. Teachers may want to substitute straws, paper squares, alphabet blocks, or such commercially made manipulatives as Unifix[R] cubes for the real sweets. Given no allergy concerns, teachers and students alike would enjoy some sweet…

  3. Dirac R-matrix calculations of photoionization cross-sections of Ni XIII

    NASA Astrophysics Data System (ADS)

    Sardar, S.; Bilal, M.; Bari, M. A.; Nazir, R. T.; Hannan, A.; Salahuddin, M.; Nasim, M. H.

    2016-05-01

    In this paper, we report total photoionization cross-sections of Ni XIII in the ground state (3P2) and four excited states (3P1,0, 1D2, 1S0) for the first time over the photon energy range 380-480 eV. The target wavefunctions are constructed with fully relativistic atomic structure GRASP code. Our calculated energy levels and oscillator strengths of core ion Ni XIV agree well with available experimental and theoretical results. The ionization threshold value of ground state of Ni XIII is found to be more closer to the experimental ionization energy and improved over the previous calculations. The photoionization cross-sections are calculated using the fully relativistic DARC code with an appropriate energy step of 0.01 eV to delineate the resonance structures. The calculated ionization cross-sections are important for the modelling of features of photoionized plasmas and for stellar opacities.

  4. Age-related changes in lung collagen metabolism. A role for degradation in regulating lung collagen production.

    PubMed

    Mays, P K; McAnulty, R J; Laurent, G J

    1989-08-01

    Lung collagen levels are determined by a balance between synthesis and degradation, processes known to have rapid rates in young animals. Here, we report age-related changes in lung collagen synthesis and degradation in rats at five ages from 1 month to 2 yr. Synthesis rates were determined after injection of [14C]proline with a flooding dose of unlabeled proline, and its appearance as hydroxy-[14C]proline in protein. To determine degradation of newly synthesized collagen, the appearance of hydroxy-[14C]proline, either free or in low-molecular-weight peptides, was compared with hydroxy-[14C]proline in protein. Fractional collagen synthesis rates decreased from 13.51 +/- 0.54%/day at 1 month to 0.97 +/- 0.14%/day at 2 yr of age (p less than 0.05). Total lung collagen production also fell, but only after 15 months, when it decreased from 2.01 +/- 0.16 mg/day at 15 months to 0.54 +/- 0.10 mg/day at 2 yr of age (p less than 0.05). Fractional rates of total collagen degradation, calculated from the difference between rates of synthesis and rates of collagen deposition, decreased 20-fold from 1 month to 2 yr of age. The proportion of newly synthesized collagen degraded increased from 27.6 +/- 3.2% at 1 month to a maximum of 82.3 +/- 1.1% at 15 months. These results suggest that lung collagen synthesis and degradation occur throughout life, and that degradative pathways may play important roles in regulating collagen production during growth and ageing. PMID:2788379

  5. Collagen Homeostasis and Metabolism.

    PubMed

    Magnusson, S Peter; Heinemeier, Katja M; Kjaer, Michael

    2016-01-01

    The musculoskeletal system and its collagen rich tissue is important for ensuring architecture of skeletal muscle, energy storage in tendon and ligaments, joint surface protection, and for ensuring the transfer of muscular forces into resulting limb movement. Structure of tendon is stable and the metabolic activity is low, but mechanical loading and subsequent mechanotransduction and molecular anabolic signaling can result in some adaptation of the tendon especially during youth and adolescence. Within short time, tendon will get stiffer with training and lack of mechanical tissue loading through inactivity or immobilization of the human body will conversely result in a dramatic loss in tendon stiffness and collagen synthesis. This illustrates the importance of regular mechanical load in order to preserve the stabilizing role of the connective tissue for the overall function of the musculoskeletal system in both daily activity and exercise. Adaptive responses may vary along the tendon, and differ between mid-substance and insertional areas of the tendon. PMID:27535245

  6. Free oscillation rheometry monitoring of haemodilution and hypothermia and correction with fibrinogen and factor XIII concentrates

    PubMed Central

    2013-01-01

    Background Haemodilution and hypothermia induce coagulopathy separately, but their combined effect on coagulation has not been widely studied. Fibrinogen concentrate can correct dilutional coagulopathy and has an additional effect when combined with factor XIII concentrate. However, their effect on dilutional coagulopathy concomitant with hypothermia has not been studied previously. Free oscillation rheometry – FOR (Reorox®) – is a novel viscoelastic haemostatic assay that has not been studied in this context before. Methods Blood from 10 healthy volunteers was diluted by 33% with hydroxyethyl starch or Ringer’s acetate solutions. Effects of fibrinogen added in vitro with and without factor XIII were studied at 33°C and 37°C. Coagulation velocity (coagulation time) and clot strength (elasticity) were assessed with FOR. Coagulation was initiated in vitro with thromboplastin alone, or thromboplastin plus a platelet inhibitor. Results Hydroxyethyl starch increased the coagulation time and decreased clot strength significantly more than Ringer’s acetate solution, both in the presence and absence of a platelet inhibitor. There was a significant interaction between haemodilution with hydroxyethyl starch and hypothermia, resulting in increased coagulation time. After addition of fibrinogen, coagulation time shortened and elasticity increased, with the exception of fibrinogen-dependent clot strength (i.e., elasticity in the presence of a platelet inhibitor) after hydroxyethyl starch haemodilution. Factor XIII had an additional effect with fibrinogen on fibrinogen-dependent clot strength in blood diluted with Ringer’s acetate solution. Hypothermia did not influence any of the coagulation factor effects. Conclusions Both haemodilution and mild hypothermia impaired coagulation. Coagulopathy was more pronounced after haemodilution with hydroxyethyl starch than with Ringer’s acetate. Addition of fibrinogen with factor XIII was unable to reverse hydroxyethyl

  7. Effect of supramolecular organization of a cartilaginous tissue on thermal stability of collagen II

    NASA Astrophysics Data System (ADS)

    Ignat'eva, N. Yu.; Averkiev, S. V.; Lunin, V. V.; Grokhovskaya, T. E.; Obrezkova, M. V.

    2006-08-01

    The thermal stability of collagen II in various cartilaginous tissues was studied. It was found that heating a tissue of nucleus pulposus results in collagen II melting within a temperature range of 60-70°C; an intact tissue of hyaline cartilage (of nasal septum and cartilage endplates) is a thermally stable system, where collagen II is not denatured completely up to 100°C. It was found that partial destruction of glycosaminoglycans in hyaline cartilage leads to an increase in the degree of denaturation of collagen II upon heating, although a significant fraction remains unchanged. It was shown that electrostatic interactions of proteoglycans and collagen only slightly affect the thermal stability of collagen II in the tissues. Evidently, proteoglycan aggregates play a key role: they create topological hindrances for moving polypeptide chains, thereby reducing the configurational entropy of collagen macromolecules in the state of a random coil.

  8. Stress-strain experiments on individual collagen fibrils.

    PubMed

    Shen, Zhilei L; Dodge, Mohammad Reza; Kahn, Harold; Ballarini, Roberto; Eppell, Steven J

    2008-10-01

    Collagen, a molecule consisting of three braided protein helices, is the primary building block of many biological tissues including bone, tendon, cartilage, and skin. Staggered arrays of collagen molecules form fibrils, which arrange into higher-ordered structures such as fibers and fascicles. Because collagen plays a crucial role in determining the mechanical properties of these tissues, significant theoretical research is directed toward developing models of the stiffness, strength, and toughness of collagen molecules and fibrils. Experimental data to guide the development of these models, however, are sparse and limited to small strain response. Using a microelectromechanical systems platform to test partially hydrated collagen fibrils under uniaxial tension, we obtained quantitative, reproducible mechanical measurements of the stress-strain curve of type I collagen fibrils, with diameters ranging from 150-470 nm. The fibrils showed a small strain (epsilon < 0.09) modulus of 0.86 +/- 0.45 GPa. Fibrils tested to strains as high as 100% demonstrated strain softening (sigma(yield) = 0.22 +/- 0.14 GPa; epsilon(yield) = 0.21 +/- 0.13) and strain hardening, time-dependent recoverable residual strain, dehydration-induced embrittlement, and susceptibility to cyclic fatigue. The results suggest that the stress-strain behavior of collagen fibrils is dictated by global characteristic dimensions as well as internal structure. PMID:18641067

  9. Stress-Strain Experiments on Individual Collagen Fibrils

    PubMed Central

    Shen, Zhilei L.; Dodge, Mohammad Reza; Kahn, Harold; Ballarini, Roberto; Eppell, Steven J.

    2008-01-01

    Collagen, a molecule consisting of three braided protein helices, is the primary building block of many biological tissues including bone, tendon, cartilage, and skin. Staggered arrays of collagen molecules form fibrils, which arrange into higher-ordered structures such as fibers and fascicles. Because collagen plays a crucial role in determining the mechanical properties of these tissues, significant theoretical research is directed toward developing models of the stiffness, strength, and toughness of collagen molecules and fibrils. Experimental data to guide the development of these models, however, are sparse and limited to small strain response. Using a microelectromechanical systems platform to test partially hydrated collagen fibrils under uniaxial tension, we obtained quantitative, reproducible mechanical measurements of the stress-strain curve of type I collagen fibrils, with diameters ranging from 150–470 nm. The fibrils showed a small strain (ɛ < 0.09) modulus of 0.86 ± 0.45 GPa. Fibrils tested to strains as high as 100% demonstrated strain softening (σyield = 0.22 ± 0.14 GPa; ɛyield = 0.21 ± 0.13) and strain hardening, time-dependent recoverable residual strain, dehydration-induced embrittlement, and susceptibility to cyclic fatigue. The results suggest that the stress-strain behavior of collagen fibrils is dictated by global characteristic dimensions as well as internal structure. PMID:18641067

  10. Heterogeneity of collagens in rabbit cornea: type VI collagen

    SciTech Connect

    Cintron, C.; Hong, B.S.

    1988-05-01

    Normal adult rabbit corneas were digested with 5% pepsin and their collagens extracted with acetic acid. Collagen extracts were fractionated by differential salt precipitation. The 2.5 M NaCl fraction was then redissolved with tris buffer and precipitated with sodium acetate. The precipitate contained a high-molecular-weight disulfide-bonded aggregate which, upon reduction with mercaptoethanol, was converted into three distinct polypeptides having molecular weights between 45 and 66 Kd. These physical characteristics, together with the susceptibility of these polypeptides to collagenase and their amino acid composition, identified the high molecular weight aggregate as type VI collagen. Corneas from neonate rabbits and adult corneas containing 2-week-old scars were organ cultured in the presence of (/sup 14/C) glycine to incorporate radiolabel into collagen. Tissues were digested with 0.02% pepsin and their collagens extracted with formic acid. The total radioactivity of the extracts and tissue residues was determined before the collagens were separated by SDS-polyacrylamide slab gel electrophoresis. Radioactive collagen polypeptides bands were then stained with Coomassie blue, processed for fluorography, and analyzed by densitometry. The results show that: (1) type VI collagen is synthesized by neonate corneas and healing adult corneas; (2) it is not readily solubilized from either corneal tissue by 0.02% pepsin digestion and formic acid extraction; and (3) the proportion of type VI collagen deposited in scar tissue is markedly lower than that found in neonate corneas.

  11. Heterogeneity of collagens in rabbit cornea: type III collagen

    SciTech Connect

    Cintron, C.; Hong, B.S.; Covington, H.I.; Macarak, E.J.

    1988-05-01

    Whole neonate rabbit corneas and adult corneas containing 2-week-old scars were incubated in the presence of (/sup 14/C) glycine. Radiolabeled collagen extracted from the corneas and scar tissue were analyzed by sodium dodecylsulfate/polyacrylamide gel electrophoresis and fluorography to determine the types and relative quantity of collagen polypeptides present and synthesized by these tissues. In addition to other collagen types, type III was found in both neonate cornea and scar tissue from adult cornea, albeit in relatively small quantities. Type III collagen in normal cornea was associated with the residue after pepsin digestion and formic acid extraction of the tissue, and the same type of collagen was extracted from scar tissue after similar treatment. Type III collagen-specific monoclonal antibody bound to developing normal corneas and healing adult tissue sections, as determined by immunofluorescence. Antibody binding was localized to the endothelium and growing Descemet's membrane in fetal and neonate corneas, and restricted to the most posterior region of the corneal scar tissue. Although monoclonal antibody to keratan sulfate, used as a marker for stromal fibroblasts, bound to most of the scar tissue, the antibody failed to bind to the posterior scar tissue positive for type III collagen. We conclude that endothelial cells from fetal and neonate rabbit cornea and endothelium-derived fibroblasts from healing wounds of adult cornea synthesize and deposit type III collagen. Moreover, this collagen appears to be incorporated into the growing Descemet's membrane of normal corneas and narrow posterior portion of the scar tissue.

  12. Osmotic pressure induced tensile forces in tendon collagen

    PubMed Central

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100 MPa, largely surpassing those of about 0.3 MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone. PMID:25608644

  13. Osmotic pressure induced tensile forces in tendon collagen

    NASA Astrophysics Data System (ADS)

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100 MPa, largely surpassing those of about 0.3 MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone.

  14. Matricryptins derived from collagens and proteoglycans.

    PubMed

    Ricard-Blum, Sylvie; Ballut, Lionel

    2011-01-01

    Controlled proteolysis of extracellular matrix components releases bioactive fragments or unmasks cryptic sites that play key roles in controlling various physio-pathological processes including angiogenesis, tissue remodeling, wound healing, inflammation, tumor growth, and metastasis. We review here the structure and mechanisms of release of i) the proteolytic fragments (matricryptins) cleaved from collagens, proteoglycans and glycosaminoglycans, and ii) the matricryptic sites existing in these molecules. The cell surface receptors and the signaling pathways they trigger to exert their biological activities is discussed with the major physio-pathological processes they control. Their involvement in autoimmune and inherited diseases is reported. Most matricryptins issued from collagens, proteoglycans and glycosaminoglycans exhibit anti-angiogenic and anti-tumor properties and their use as potential drugs and as potential disease markers is discussed. Perspectives for identifying the common structural features, if any, of the matricryptins and their use in combination with chemotherapy and radiotherapy in the treatment of cancer are presented. PMID:21196195

  15. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride.

    PubMed

    Li, Conghu; Tian, Zhenhua; Liu, Wentao; Li, Guoying

    2015-10-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen. PMID:26117763

  16. Lysyl Hydroxylase 3-mediated Glucosylation in Type I Collagen

    PubMed Central

    Sricholpech, Marnisa; Perdivara, Irina; Yokoyama, Megumi; Nagaoka, Hideaki; Terajima, Masahiko; Tomer, Kenneth B.; Yamauchi, Mitsuo

    2012-01-01

    Recently, by employing the short hairpin RNA technology, we have generated MC3T3-E1 (MC)-derived clones stably suppressing lysyl hydroxylase 3 (LH3) (short hairpin (Sh) clones) and demonstrated the LH3 function as glucosyltransferase in type I collagen (Sricholpech, M., Perdivara, I., Nagaoka, H., Yokoyama, M., Tomer, K. B., and Yamauchi, M. (2011) Lysyl hydroxylase 3 glucosylates galactosylhydroxylysine residues in type I collagen in osteoblast culture. J. Biol. Chem. 286, 8846–8856). To further elucidate the biological significance of this modification, we characterized and compared type I collagen phenotypes produced by Sh clones and two control groups, MC and those transfected with empty vector. Mass spectrometric analysis identified five glycosylation sites in type I collagen (i.e. α1,2-87, α1,2-174, and α2-219. Of these, the predominant glycosylation site was α1-87, one of the major helical cross-linking sites. In Sh collagen, the abundance of glucosylgalactosylhydroxylysine was significantly decreased at all of the five sites with a concomitant increase in galactosylhydroxylysine at four of these sites. The collagen cross-links were significantly diminished in Sh clones, and, for the major cross-link, dihydroxylysinonorleucine (DHLNL), glucosylgalactosyl-DHLNL was diminished with a concomitant increase in galactosyl-DHLNL. When subjected to in vitro incubation, in Sh clones, the rate of decrease in DHLNL was lower, whereas the rate of increase in its maturational cross-link, pyridinoline, was comparable with controls. Furthermore, in Sh clones, the mean diameters of collagen fibrils were significantly larger, and the onset of mineralized nodule formation was delayed when compared with those of controls. These results indicate that the LH3-mediated glucosylation occurs at the specific molecular loci in the type I collagen molecule and plays critical roles in controlling collagen cross-linking, fibrillogenesis, and mineralization. PMID:22573318

  17. Arterial calcification: Conscripted by collagen

    NASA Astrophysics Data System (ADS)

    Miller, Jordan D.

    2016-03-01

    In atherosclerotic plaques, patterns of calcification -- which have profound implications for plaque stability and vulnerability to rupture -- are determined by the collagen's content and patterning throughout the plaque.

  18. 40 CFR Appendix Xiii to Part 86 - State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations XIII Appendix XIII to Part 86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

  19. 40 CFR Appendix Xiii to Part 86 - State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations XIII Appendix XIII to Part 86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

  20. 40 CFR Appendix Xiii to Part 86 - State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations XIII Appendix XIII to Part 86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

  1. 40 CFR Appendix Xiii to Part 86 - State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false State Requirements Incorporated by Reference in Part 86 of the Code of Federal Regulations XIII Appendix XIII to Part 86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

  2. Collagen dynamics of partial small bowel obstruction

    SciTech Connect

    Stromberg, B.V.; Klein, L.

    1984-08-01

    The response of intestinal collagen to obstruction and stress was studied in the rat. Partial small bowel obstructions were created. Preobstruction collagen was measured by injection of tritium labeled proline. New collagen formation after obstruction occurred was followed by injection of carbon-14 labeled proline. At 3 weeks, collagen fractions were identified. Throughout the study, preexisting preobstruction intestinal collagen was metabolically stable with no breakdown or remodeling demonstrable. New collagen formation was rapid and occurred to the largest degree close to the obstruction.

  3. Platelet collagen receptors and coagulation. A characteristic platelet response as possible target for antithrombotic treatment.

    PubMed

    Heemskerk, Johan W M; Kuijpers, Marijke J E; Munnix, Imke C A; Siljander, Pia R M

    2005-04-01

    Collagen is a unique agonist of platelets, because it acts as an immobilized ligand that only causes platelet activation after stable adhesion. This review addresses the present understanding of how platelet interaction with collagen supports the process of thrombin generation and coagulation. Only some of the collagen-adhered platelets, that is, those showing profound changes in shape and shedding microparticles (resembling apoptotic cells), appear to contribute to the procoagulant activity of platelets. The main signaling receptor for collagen, glycoprotein VI, plays a key role in the platelet procoagulant response during thrombus formation; this is a reason why new anti-glycoprotein-VI antibodies are promising antithrombotic tools. PMID:16039967

  4. Effect of photon energy in collagen generation by interstitial low level laser stimulation

    NASA Astrophysics Data System (ADS)

    Jun, Eunkwon; Ha, Myungjin; Lee, Sangyeob; Radfar, Edalat; Park, Jihoon; Jung, Byungjo

    2015-03-01

    Although the mechanism of low level laser therapy (LLLT) is unclear, many studies demonstrated the positive clinical performance of LLLT for skin rejuvenation. An increase in dermal collagen plays an important role in skin rejuvenation and wound healing. This study aimed to investigate collagen generation after interstitial low level laser stimulation (ILLS). Rabbits were divided into two groups: surfacing irradiation and minimally invasive irradiation. 660nm diode laser of 20mW with 10J, 13J and 15J was applied to the backside of rabbits. Collagen formation was evaluated with ultrasound skin scanner every 12 hours. Results shows that ILLS groups have denser collagen density than surfacing groups.

  5. Mechano-regulation of Collagen Biosynthesis in Periodontal Ligament

    PubMed Central

    Kaku, Masaru; Yamauchi, Mitsuo

    2014-01-01

    Purpose Periodontal ligament (PDL) plays critical roles in the development and maintenance of periodontium such as tooth eruption and dissipation of masticatory force. The mechanical properties of PDL are mainly derived from fibrillar type I collagen, the most abundant extracellular component. Study selection The biosynthesis of type I collagen is a long, complex process including a number of intra- and extracellular post-translational modifications. The final modification step is the formation of covalent intra- and intermolecular cross-links that provide collagen fibrils with stability and connectivity. Results It is now clear that collagen post-translational modifications are regulated by groups of specific enzymes and associated molecules in a tissue-specific manner; and these modifications appear to change in response to mechanical force. Conclusions This review focuses on the effect of mechanical loading on collagen biosynthesis and fibrillogenesis in PDL with emphasis on the post-translational modifications of collagens, which is an important molecular aspect to understand in the field of prosthetic dentistry. PMID:25311991

  6. Hydroxyproline-free single composition ABC collagen heterotrimer.

    PubMed

    Jalan, Abhishek A; Demeler, Borries; Hartgerink, Jeffrey D

    2013-04-24

    Hydroxyproline plays a major role in stabilizing collagenous domains in eukaryotic organisms. Lack of this modification is associated with significant lowering in the thermal stability of the collagen triple helix and may also affect fibrillogenesis and folding of the peptide chains. In contrast, even though bacterial collagens lack hydroxyproline, their thermal stability is comparable to that of fibrillar collagen. This has been attributed to the high frequency of charged amino acids found in bacterial collagen. Here we report a thermally stable hydroxyproline-free ABC heterotrimeric collagen mimetic system composed of decapositive and decanegative peptides and a zwitterionic peptide. None of the peptides contain hydroxyproline, and furthermore the zwitterionic peptide does not even contain proline. The heterotrimer is electrostatically stabilized via multiple interpeptide lysine-aspartate and lysine-glutamate salt bridges and maintains good thermal stability with a melting temperature of 37 °C. The ternary peptide mixture also populates a single composition ABC heterotrimer as confirmed by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. This system illustrates the power of axial salt bridges to direct and stabilize the self-assembly of a triple helix and may be useful in analogous designs in expression systems where the incorporation of hydroxyproline is challenging. PMID:23574286

  7. Measurement of the quadratic hyperpolarizability of the collagen triple helix and application to second harmonic imaging of natural and biomimetic collagenous tissues

    NASA Astrophysics Data System (ADS)

    Deniset-Besseau, A.; Strupler, M.; Duboisset, J.; De Sa Peixoto, P.; Benichou, E.; Fligny, C.; Tharaux, P.-L.; Mosser, G.; Brevet, P.-F.; Schanne-Klein, M.-C.

    2009-09-01

    Collagen is a major protein of the extracellular matrix that is characterized by triple helical domains. It plays a central role in the formation of fibrillar and microfibrillar networks, basement membranes, as well as other structures of the connective tissue. Remarkably, fibrillar collagen exhibits efficient Second Harmonic Generation (SHG) so that SHG microscopy proved to be a sensitive tool to probe the three-dimensional architecture of fibrillar collagen and to assess the progression of fibrotic pathologies. We obtained sensitive and reproducible measurements of the fibrosis extent, but we needed quantitative data at the molecular level to further process SHG images. We therefore performed Hyper- Rayleigh Scattering (HRS) experiments and measured a second order hyperpolarisability of 1.25 10-27 esu for rat-tail type I collagen. This value is surprisingly large considering that collagen presents no strong harmonophore in its aminoacid sequence. In order to get insight into the physical origin of this nonlinear process, we performed HRS measurements after denaturation of the collagen triple helix and for a collagen-like short model peptide [(Pro-Pro- Gly)10]3. It showed that the collagen large nonlinear response originates in the tight alignment of a large number of weakly efficient harmonophores, presumably the peptide bonds, resulting in a coherent amplification of the nonlinear signal along the triple helix. To illustrate this mechanism, we successfully recorded SHG images in collagenous biomimetic matrices.

  8. Acid phosphatase activity and intracellular collagen degradation by fibroblasts in vitro.

    PubMed

    Yajima, T

    1986-01-01

    Human gingival fibroblasts were cultured with collagen fibrils. The precise process of collagen phagocytosis and the relationship between acid phosphatase activity and intracellular degradation of collagen were investigated by cytochemical methods at the ultrastructural level. The collagen fibrils were first engulfed at one end by cellular processes, or the cell membrane wrapped itself around the middle of the fibrils. Collagen phagocytosis induced acid phosphatase activity in the fibroblast Golgi-endoplasmic reticulum-lysosome system. By application of the tracer lanthanum, deposits were observed in the intercellular spaces and along the fibrils being phagocytosed. At this stage, primary lysosomes were seen in close proximity to the collagen being engulfed, but no signs of fusion were observed. When the fibrils had been interiorized in whole or in part, they ultimately became enclosed within phagosomes, and no tracer was observed along the interiorized portion of the fibrils. Primary lysosomes then fused with these collagen-containing phagosomes to form phagolysosomes. Collagen degradation occurred within these bodies even though the end of a fibril might have protruded outside of the cell. These results suggest that selective and controlled phagocytosis of collagen and intracellular digestion of it may play a central role in the physiological remodeling and metabolic breakdown of the collagen of connective tissues. PMID:3742560

  9. The effect of collagen ageing on its structure and cellular behaviour

    NASA Astrophysics Data System (ADS)

    Wilson, Samantha L.; Guilbert, Marie; Sulé-Suso, Josep; Torbet, James; Jeannesson, Pierre; Sockalingum, Ganesh D.; Yang, Ying

    2012-03-01

    Collagen is the most important component in extracellular matrix (ECM) and plays a pivotal role in individual tissue function in mammals. During ageing, collagen structure changes, which can detrimentally affect its biophysical and biomechanical properties due to an accumulation of advanced glycation end-products (AGEs). AGEs have been linked to non-enzymatic cross-linking of proteins resulting in the alteration of mechanical properties of the tissue. In this study we investigate the influence of different aged collagens on the mechanical and contractile properties of reconstituted hydrogel constructs seeded with corneal stromal fibroblasts. A non-destructive indentation technique and optical coherence tomography (OCT) are used to determine the elastic modulus and dimensional changes respectively. It is revealed that the youngest collagen constructs have a higher elastic modulus and increased contraction compared to the older collagen. These results provide new insights into the relationship between collagen molecular structures and their biomechanical properties.

  10. Role of Preferential Ions of Ammonium Ionic Liquid in Destabilization of Collagen.

    PubMed

    Tarannum, Aafiya; Muvva, Charuvaka; Mehta, Ami; Raghava Rao, J; Fathima, N Nishad

    2016-07-14

    Ions play a key role in the destabilization of collagen. This study explores the effect of diethyl methyl ammonium methane sulfonate (AMS), an ionic liquid (IL), on different hierarchical orderings of collagen, namely, at the molecular and fibrillar levels. The rheological behavior and secondary structural changes reveal changes in the hydrogen-bonding environment of collagen, leading to alterations in the triple helical structure of collagen. An increase in the concentration of AMS resulted in swelling of rat-tail tendon fibers, and also, decreased thermal stability signifies that ions are obliged to destabilize collagen at the fibrillar level. Molecular modeling studies confirm that anions are judiciously held responsible for structural deformities in collagen, whereas cations have a tenuous effect. Thus, the preferential role of ions present in an ammonium IL has been elucidated in this study. PMID:27327186

  11. Second-harmonic generation imaging of collagen fibers in myocardium for atrial fibrillation diagnosis

    NASA Astrophysics Data System (ADS)

    Tsai, Ming-Rung; Chiu, Yu-Wei; Lo, Men Tzung; Sun, Chi-Kuang

    2010-03-01

    Atrial fibrillation (AF) is the most common irregular heart rhythm and the mortality rate for patients with AF is approximately twice the mortality rate for patients with normal sinus rhythm (NSR). Some research has indicated that myocardial fibrosis plays an important role in predisposing patients to AF. Therefore, realizing the relationship between myocardial collagen fibrosis and AF is significant. Second-harmonic generation (SHG) is an optically nonlinear coherent process to image the collagen network. We perform SHG microscopic imaging of the collagen fibers in the human atrial myocardium. Utilizing the SHG images, we can identify the differences in morphology and the arrangement of collagen fibers between NSR and AF tissues. We also quantify the arrangement of the collagen fibers using Fourier transform images and calculating the values of angle entropy. We indicate that SHG imaging, a nondestructive and reproducible method to analyze the arrangement of collagen fibers, can provide explicit information about the relationship between myocardial fibrosis and AF.

  12. Type I Collagen and Collagen Mimetics as Angiogenesis Promoting Superpolymers

    SciTech Connect

    Twardowski, T.; Fertala, A.; Orgel, J.P.R.O.; San Antonio, J.D.

    2008-07-18

    Angiogenesis, the development of blood vessels from the pre-existing vasculature, is a key component of embryogenesis and tissue regeneration. Angiogenesis also drives pathologies such as tumor growth and metastasis, and hemangioma development in newborns. On the other hand, promotion of angiogenesis is needed in tissues with vascular insufficiencies, and in bioengineering, to endow tissue substitutes with appropriate microvasculatures. Therefore, much research has focused on defining mechanisms of angiogenesis, and identifying pro- and anti-angiogenic molecules. Type I collagen, the most abundant protein in humans, potently stimulates angiogenesis in vitro and in vivo. Crucial to its angiogenic activity appears to be ligation and possibly clustering of endothelial cell (EC) surface {alpha}1{beta}1/{alpha}2{beta}1 integrin receptors by the GFPGER502-507 sequence of the collagen fibril. However, additional aspects of collagen structure and function that may modulate its angiogenic properties are discussed. Moreover, type I collagen and fibrin, another angiogenic polymer, share several structural features. These observations suggest strategies for creating 'angiogenic superpolymers', including: modifying type I collagen to influence its biological half-life, immunogenicity, and integrin binding capacity; genetically engineering fibrillar collagens to include additional integrin binding sites or angiogenic determinants, and remove unnecessary or deleterious sequences without compromising fibril integrity; and exploring the suitability of poly(ortho ester), PEG-lysine copolymer, tubulin, and cholesteric cuticle as collagen mimetics, and suggesting means of modifying them to display ideal angiogenic properties. The collagenous and collagen mimetic angiogenic superpolymers described here may someday prove useful for many applications in tissue engineering and human medicine.

  13. Lumican deficiency results in cardiomyocyte hypertrophy with altered collagen assembly.

    PubMed

    Dupuis, Loren E; Berger, Matthew G; Feldman, Samuel; Doucette, Lorna; Fowlkes, Vennece; Chakravarti, Shukti; Thibaudeau, Sarah; Alcala, Nicolas E; Bradshaw, Amy D; Kern, Christine B

    2015-07-01

    The ability of the heart to adapt to increased stress is dependent on the modification of its extracellular matrix (ECM) architecture that is established during postnatal development as cardiomyocytes differentiate, a process that is poorly understood. We hypothesized that the small leucine-rich proteoglycan (SLRP) lumican (LUM), which binds collagen and facilitates collagen assembly in other tissues, may play a critical role in establishing the postnatal murine myocardial ECM. Although previous studies suggest that LUM deficient mice (lum(-/-)) exhibit skin anomalies consistent with Ehlers-Danlos syndrome, lum(-/-) hearts have not been evaluated. These studies show that LUM was immunolocalized to non-cardiomyocytes of the cardiac ventricles and its expression increased throughout development. Lumican deficiency resulted in significant (50%) perinatal death and further examination of the lum(-/-) neonatal hearts revealed an increase in myocardial tissue without a significant increase in cell proliferation. However cardiomyocytes from surviving postnatal day 0 (P0), 1 month (1 mo) and adult (4 mo) lum(-/-) hearts were significantly larger than their wild type (WT) littermates. Immunohistochemistry revealed that the increased cardiomyocyte size in the lum(-/-) hearts correlated with alteration of the cardiomyocyte pericellular ECM components collagenα1(I) and the class I SLRP decorin (DCN). Western blot analysis demonstrated that the ratio of glycosaminoglycan (GAG) decorated DCN to core DCN was reduced in P0 and 1 mo lum(-/-) hearts. There was also a reduction in the β and γ forms of collagenα1(I) in lum(-/-) hearts. While the total insoluble collagen content was significantly reduced, the fibril size was increased in lum(-/-) hearts, indicating that LUM may play a role in collagen fiber stability and lateral fibril assembly. These results suggest that LUM controls cardiomyocyte growth by regulating the pericellular ECM and also indicates that LUM may coordinate

  14. Electrostatic effects in collagen fibrillization

    NASA Astrophysics Data System (ADS)

    Morozova, Svetlana; Muthukumar, Murugappan

    2014-03-01

    Using light scattering and AFM techniques, we have measured the kinetics of fibrillization of collagen (pertinent to the vitreous of human eye) as a function of pH and ionic strength. At higher and lower pH, collagen triple-peptides remain stable in solution without fibrillization. At neutral pH, the fibrillization occurs and its growth kinetics is slowed upon either an increase in ionic strength or a decrease in temperature. We present a model, based on polymer crystallization theory, to describe the observed electrostatic nature of collagen assembly.

  15. ADAM10 controls collagen signaling and cell migration on collagen by shedding the ectodomain of discoidin domain receptor 1 (DDR1)

    PubMed Central

    Shitomi, Yasuyuki; Thøgersen, Ida B.; Ito, Noriko; Leitinger, Birgit; Enghild, Jan J.; Itoh, Yoshifumi

    2015-01-01

    Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that binds and transmits signals from various collagens in epithelial cells. However, how DDR1–dependent signaling is regulated has not been understood. Here we report that collagen binding induces ADAM10-dependent ectodomain shedding of DDR1. DDR1 shedding is not a result of an activation of its signaling pathway, since DDR1 mutants defective in signaling were shed in an efficient manner. DDR1 and ADAM10 were found to be in a complex on the cell surface, but shedding did not occur unless collagen bound to DDR1. Using a shedding-resistant DDR1 mutant, we found that ADAM10-dependent DDR1 shedding regulates the half-life of collagen-induced phosphorylation of the receptor. Our data also revealed that ADAM10 plays an important role in regulating DDR1-mediated cell adhesion to achieve efficient cell migration on collagen matrices. PMID:25540428

  16. Nature designs tough collagen: Explaining the nanostructure of collagen fibrils

    PubMed Central

    Buehler, Markus J.

    2006-01-01

    Collagen is a protein material with superior mechanical properties. It consists of collagen fibrils composed of a staggered array of ultra-long tropocollagen (TC) molecules. Theoretical and molecular modeling suggests that this natural design of collagen fibrils maximizes the strength and provides large energy dissipation during deformation, thus creating a tough and robust material. We find that the mechanics of collagen fibrils can be understood quantitatively in terms of two critical molecular length scales χS and χR that characterize when (i) deformation changes from homogeneous intermolecular shear to propagation of slip pulses and when (ii) covalent bonds within TC molecules begin to fracture, leading to brittle-like failure. The ratio χS/χR indicates which mechanism dominates deformation. Our modeling rigorously links the chemical properties of individual TC molecules to the macroscopic mechanical response of fibrils. The results help to explain why collagen fibers found in nature consist of TC molecules with lengths in the proximity of 300 nm and advance the understanding how collagen diseases that change intermolecular adhesion properties influence mechanical properties. PMID:16895989

  17. FE-XIII Infrared / FE-XIV Green Line Ratio Diagnostics (P55)

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; et al.

    2006-11-01

    aks.astro.itbhu@gmail.com We consider the first 27-level atomic model of Fe XIII (5.9 < log Te < 6.4 K) to estimate its ground level populations, taking account of electron as well as proton collisional excitations and de-excitations, radiative cascades, radiative excitations and de-excitations. Radiative cascade is important but the effect of dilution factor is negligible at higher electron densities. The 3 P1-3P0 and 3P2-3P1 transitions in the ground configuration 3s2 3p2 of Fe XIII result in two forbidden coronal emission lines in the infrared region, namely 10747 Å and 10798 Å., while the 5303 Å green line is formed in the 3s2 3p 2 2 ground configuration of Fe XIV as a result of P3 / 2 - P1 / 2 magnetic dipole transition. The line-widths of appropriate pair of forbidden coronal emission lines observed simultaneously can be useful diagnostic tool to deduce temperature and non-thermal velocity in the large scale coronal structures using intensity ratios of the lines as the temperature signature, instead of assuming ion temperature to be equal to the electron temperature. Since the line intensity ratios IG5303/IIR10747 and IG5303/IIR10798 have very week density dependence, they are ideal monitors of temperature mapping in the solar corona.

  18. VizieR Online Data Catalog: SiXIII and SXV collision strengths (Fernandez-Menchero+, 2016)

    NASA Astrophysics Data System (ADS)

    Fernandez-Menchero, L.; Del Zanna, G.; Badnell, N. R.

    2016-07-01

    In present online material we provide in CDS format the extrapolated values of energies, radiative parameters (gf), and electron-impact excitation effective collision strengths (Upsilon) obtained with the extrapolation rules described in the manuscript for the two test ions: He-like Si XIII and S XV. (6 data files).

  19. Nonlinear microscopy of collagen fibers

    NASA Astrophysics Data System (ADS)

    Strupler, M.; Pena, A.-M.; Hernest, M.; Tharaux, P.-L.; Fabre, A.; Marchal-Somme, J.; Crestani, B.; Débarre, D.; Martin, J.-L.; Beaurepaire, E.; Schanne-Klein, M.-C.

    2007-02-01

    We used intrinsic Second Harmonic Generation (SHG) by fibrillar collagen to visualize the three-dimensional architecture of collagen fibrosis at the micrometer scale using laser scanning nonlinear microscopy. We showed that SHG signals are highly specific to fibrillar collagen and provide a sensitive probe of the micrometer-scale structural organization of collagen in tissues. Moreover, recording simultaneously other nonlinear optical signals in a multimodal setup, we visualized the tissue morphology using Two-Photon Excited Fluorescence (2PEF) signals from endogenous chromophores such as NADH or elastin. We then compared different methods to determine accurate indexes of collagen fibrosis using nonlinear microscopy, given that most collagen fibrils are smaller than the microscope resolution and that second harmonic generation is a coherent process. In order to define a robust method to process our three-dimensional images, we either calculated the fraction of the images occupied by a significant SHG signal, or averaged SHG signal intensities. We showed that these scores provide an estimation of the extension of renal and pulmonary fibrosis in murine models, and that they clearly sort out the fibrotic mice.

  20. Human collagen produced in plants

    PubMed Central

    Shoseyov, Oded; Posen, Yehudit; Grynspan, Frida

    2014-01-01

    Consequential to its essential role as a mechanical support and affinity regulator in extracellular matrices, collagen constitutes a highly sought after scaffolding material for regeneration and healing applications. However, substantiated concerns have been raised with regard to quality and safety of animal tissue-extracted collagen, particularly in relation to its immunogenicity, risk of disease transmission and overall quality and consistency. In parallel, contamination with undesirable cellular factors can significantly impair its bioactivity, vis-a-vis its impact on cell recruitment, proliferation and differentiation. High-scale production of recombinant human collagen Type I (rhCOL1) in the tobacco plant provides a source of an homogenic, heterotrimeric, thermally stable “virgin” collagen which self assembles to fine homogenous fibrils displaying intact binding sites and has been applied to form numerous functional scaffolds for tissue engineering and regenerative medicine. In addition, rhCOL1 can form liquid crystal structures, yielding a well-organized and mechanically strong membrane, two properties indispensable to extracellular matrix (ECM) mimicry. Overall, the shortcomings of animal- and cadaver-derived collagens arising from their source diversity and recycled nature are fully overcome in the plant setting, constituting a collagen source ideal for tissue engineering and regenerative medicine applications. PMID:23941988

  1. Characterisations of collagen-silver-hydroxyapatite nanocomposites

    NASA Astrophysics Data System (ADS)

    Ciobanu, C. S.; Popa, C. L.; Petre, C. C.; Jiga, G.; Trusca, R.; Predoi, D.

    2016-05-01

    The XRD analysis were performed to confirm the formation of hydroxyapatite structure in collagen-silver-hydroxyapatite nanocomposites. The molecular interaction in collagen-hydroxyapatite nanocomposites was highlighted by Fourier transform infrared spectroscopy (FTIR) analysis. The SEM showed a nanostructure of collagen-silverhydroxyapatite nanocomposites composed of nano needle-like particles in a veil with collagen texture. The presence of vibrational groups characteristics to the hydroxyapatite structure in collagen-silver-hydroxyapatite (AgHApColl) nanocomposites was investigated by FTIR.

  2. Identification of an Electrostatic Ruler Motif for Sequence-Specific Binding of Collagenase to Collagen.

    PubMed

    Subramanian, Sundar Raman; Singam, Ettayapuram Ramaprasad Azhagiya; Berinski, Michael; Subramanian, Venkatesan; Wade, Rebecca C

    2016-08-25

    Sequence-specific cleavage of collagen by mammalian collagenase plays a pivotal role in cell function. Collagenases are matrix metalloproteinases that cleave the peptide bond at a specific position on fibrillar collagen. The collagenase Hemopexin-like (HPX) domain has been proposed to be responsible for substrate recognition, but the mechanism by which collagenases identify the cleavage site on fibrillar collagen is not clearly understood. In this study, Brownian dynamics simulations coupled with atomic-detail and coarse-grained molecular dynamics simulations were performed to dock matrix metalloproteinase-1 (MMP-1) on a collagen IIIα1 triple helical peptide. We find that the HPX domain recognizes the collagen triple helix at a conserved R-X11-R motif C-terminal to the cleavage site to which the HPX domain of collagen is guided electrostatically. The binding of the HPX domain between the two arginine residues is energetically stabilized by hydrophobic contacts with collagen. From the simulations and analysis of the sequences and structural flexibility of collagen and collagenase, a mechanistic scheme by which MMP-1 can recognize and bind collagen for proteolysis is proposed. PMID:27245212

  3. Control of melanoma cell invasion by type IV collagen.

    PubMed

    Pasco, Sylvie; Brassart, Bertrand; Ramont, Laurent; Maquart, François-Xavier; Monboisse, Jean-Claude

    2005-01-01

    Malignant melanoma is the leading cause of death from diseases of the skin. This review summarizes the data from the literature and our laboratory addressing the effects of type IV collagen on melanoma progression. Many different sequences from type IV collagen promote melanoma cell adhesion, migration and invasion. The triple helical conformation of the collagenous domain plays a critical role in some of these interactions. However, recent studies from our group demonstrated that a sequence from the alpha3(IV) NC1 domain inhibits melanoma cell proliferation, migration and invasion by decreasing MMP production and activation. Peptide sequences from the alpha1(IV), alpha2(IV) and alpha3(IV) chains named arresten, canstatin and tumstatin, respectively were shown to inhibit angiogenesis. Further investigations regarding the inhibitory effects of the alpha(IV) NC1 domains will have a paramount relevance for the design of efficient strategies to limit melanoma development. PMID:15936594

  4. Measurement of the Mechanical Properties of Intact Collagen Fibrils

    NASA Astrophysics Data System (ADS)

    Mercedes, H.; Heim, A.; Matthews, W. G.; Koob, T.

    2006-03-01

    Motivated by the genetic disorder Ehlers-Danlos syndrome (EDS), in which proper collagen synthesis is interrupted, we are investigating the structural and mechanical properties of collagen fibrils. The fibrous glycoprotein collagen is the most abundant protein found in the human body and plays a key role in the extracellular matrix of the connective tissue, the properties of which are altered in EDS. We have selected as our model system the collagen fibrils of the sea cucumber dermis, a naturally mutable tissue. This system allows us to work with native fibrils which have their proteoglycan complement intact, something that is not possible with reconstituted mammalian collagen fibrils. Using atomic force microscopy, we measure, as a function of the concentration of divalent cations, the fibril diameter, its response to force loading, and the changes in its rigidity. Through these experiments, we will shed light on the mechanisms which control the properties of the sea cucumber dermis and hope to help explain the altered connective tissue extracellular matrix properties associated with EDS.

  5. Nanomechanics of Type I Collagen.

    PubMed

    Varma, Sameer; Orgel, Joseph P R O; Schieber, Jay D

    2016-07-12

    Type I collagen is the predominant collagen in mature tendons and ligaments, where it gives them their load-bearing mechanical properties. Fibrils of type I collagen are formed by the packing of polypeptide triple helices. Higher-order structures like fibril bundles and fibers are assembled from fibrils in the presence of other collagenous molecules and noncollagenous molecules. Curiously, however, experiments show that fibrils/fibril bundles are less resistant to axial stress compared to their constituent triple helices-the Young's moduli of fibrils/fibril bundles are an order-of-magnitude smaller than the Young's moduli of triple helices. Given the sensitivity of the Young's moduli of triple helices to solvation environment, a plausible explanation is that the packing of triple helices into fibrils perhaps reduces the Young's modulus of an individual triple helix, which results in fibrils having smaller Young's moduli. We find, however, from molecular dynamics and accelerated conformational sampling simulations that the Young's modulus of the buried core of the fibril is of the same order as that of a triple helix in aqueous phase. These simulations, therefore, suggest that the lower Young's moduli of fibrils/fibril bundles cannot be attributed to the specific packing of triple helices in the fibril core. It is not the fibril core that yields initially to axial stress. Rather, it must be the portion of the fibril exposed to the solvent and/or the fibril-fibril interface that bears the initial strain. Overall, this work provides estimates of Young's moduli and persistence lengths at two levels of collagen's structural assembly, which are necessary to quantitatively investigate the response of various biological factors on collagen mechanics, including congenital mutations, posttranslational modifications and ligand binding, and also engineer new collagen-based materials. PMID:27410733

  6. Enhanced stabilization of collagen by furfural.

    PubMed

    Lakra, Rachita; Kiran, Manikantan Syamala; Usha, Ramamoorthy; Mohan, Ranganathan; Sundaresan, Raja; Korrapati, Purna Sai

    2014-04-01

    Furfural (2-furancarboxaldehyde), a product derived from plant pentosans, has been investigated for its interaction with collagen. Introduction of furfural during fibril formation enhanced the thermal and mechanical stability of collagen. Collagen films treated with furfural exhibited higher denaturation temperature (Td) (p<0.04) and showed a 3-fold increase in Young's modulus (p<0.04) at higher concentration. Furfural and furfural treated collagen films did not have any cytotoxic effect. Rheological characterization showed an increase in shear stress and shear viscosity with increasing shear rate for treated collagen. Circular dichroism (CD) studies indicated that the furfural did not have any impact on triple helical structure of collagen. Scanning electron microscopy (SEM) of furfural treated collagen exhibited small sized porous structure in comparison with untreated collagen. Thus this study provides an alternate ecologically safe crosslinking agent for improving the stability of collagen for biomedical and industrial applications. PMID:24468046

  7. PIXE and IL analysis of an archeologically problematic XIII century ceramic production

    NASA Astrophysics Data System (ADS)

    Zucchiatti, Alessandro; Jiménez-Rey, David; Climent-Font, Aurelio; Martina, Silvia; Faieta, Rosangela; Maggi, Marco; Giuntini, Lorenzo; Calusi, Silvia

    2015-11-01

    At the beginning of the XIII century the archaeologists have found evidence of a singular, transitional, pottery technique limited to a small area around western Liguria (Northwest of Italy). Known as Ligurian Protomajolica (PML), it shows in the same ceramic body and on the same surface white slip and enamel together, addressing questions about the technical reasons of this unusual combination, its origin and evolution. To integrate previous morphological and mineralogical studies, we have analysed by particle induced X-ray emission (also with mapping) and ionoluminescence (IL) the ceramic body, slip and glaze composition of 56 samples, of which 25 PML's. We have identified some PML's compositional features which are distinct from those of other coeval or later productions from the same area. A few PML imitations are described. A plausible explanation of the origin of the PML's, based both on the archaeometric results and the archaeological and historical knowledge, is presented.

  8. Saccharin sulfonamides as inhibitors of carbonic anhydrases I, II, VII, XII, and XIII.

    PubMed

    Morkūnaitė, Vaida; Baranauskienė, Lina; Zubrienė, Asta; Kairys, Visvaldas; Ivanova, Jekaterina; Trapencieris, Pēteris; Matulis, Daumantas

    2014-01-01

    A series of modified saccharin sulfonamides have been designed as carbonic anhydrase (CA) inhibitors and synthesized. Their binding to CA isoforms I, II, VII, XII, and XIII was measured by the fluorescent thermal shift assay (FTSA) and isothermal titration calorimetry (ITC). Saccharin bound the CAs weakly, exhibiting the affinities of 1-10 mM for four CAs except CA I where binding could not be detected. Several sulfonamide-bearing saccharines exhibited strong affinities of 1-10 nM towards particular CA isoforms. The functional group binding Gibbs free energy additivity maps are presented which may provide insights into the design of compounds with increased affinity towards selected CAs. PMID:25276805

  9. Saccharin Sulfonamides as Inhibitors of Carbonic Anhydrases I, II, VII, XII, and XIII

    PubMed Central

    Morkūnaitė, Vaida; Baranauskienė, Lina; Zubrienė, Asta; Trapencieris, Pēteris

    2014-01-01

    A series of modified saccharin sulfonamides have been designed as carbonic anhydrase (CA) inhibitors and synthesized. Their binding to CA isoforms I, II, VII, XII, and XIII was measured by the fluorescent thermal shift assay (FTSA) and isothermal titration calorimetry (ITC). Saccharin bound the CAs weakly, exhibiting the affinities of 1–10 mM for four CAs except CA I where binding could not be detected. Several sulfonamide-bearing saccharines exhibited strong affinities of 1–10 nM towards particular CA isoforms. The functional group binding Gibbs free energy additivity maps are presented which may provide insights into the design of compounds with increased affinity towards selected CAs. PMID:25276805

  10. Autoimmune antibody (IgG Kansas) against the fibrin stabilizing factor (factor XIII) system.

    PubMed Central

    Lorand, L; Velasco, P T; Rinne, J R; Amare, M; Miller, L K; Zucker, M L

    1988-01-01

    Serum from a patient who died from massive hemorrhage within 4 months after onset of an acquired bleeding disorder at age 85 contained a potent inhibitor of fibrin stabilization. Other parameters of coagulation and fibrinolysis and his bleeding time were within normal limits. The inhibitor was shown to be an IgG with kappa light chains (IgG Kansas); its specific target was the factor XIII system itself. Although IgG Kansas combined with the virgin [ab] form of the zymogen, it did not block the thrombin-catalyzed conversion to [a'b]. However, IgG Kansas prevented the subsequent Ca2+-mediated activation of [a'b] to a + b, where a denotes the catalytically competent factor XIIIa species. IgG Kansas, in contrast to a previously studied autoimmune antibody from a similar bleeding disorder (IgG Warsaw), could also inhibit the transamidating activity of the preactivated a enzyme. Images PMID:3422419

  11. Laboratory Diagnosis of Factor XIII Deficiency in Developing Countries: An Iranian Experience.

    PubMed

    Dorgalaleh, Akbar; Tabibian, Shadi; Shams, Mahmood; Tavasoli, Behnaz; Gheidishahran, Maryam; Shamsizadeh, Morteza

    2016-08-01

    Factor XIII (FXIII) deficiency is an extremely rare bleeding disorder with an approximately 12-times higher than the rest of the world. The International Society for Thrombosis and Hemostasis (ISTH) suggested a standard algorithm for precise diagnosis and classification of FXIII deficiency (FXIIID). However, due to lack of investment in proper equipment and procedures in Iran, almost no part of this algorithm can be used to diagnose Iranian patients. Thus, this study proposes a guideline for accurate molecular and laboratory diagnosis of FXIIID based on the available tools. Because this study suggests a simple and reliable algorithm for early diagnosis, it can therefore, reduce the rates of morbidity and mortality of FXIIID patients with this condition. PMID:27346867

  12. Platelet factor XIII increases the fibrinolytic resistance of platelet-rich clots by accelerating the crosslinking of alpha 2-antiplasmin to fibrin

    NASA Technical Reports Server (NTRS)

    Reed, G. L.; Matsueda, G. R.; Haber, E.

    1992-01-01

    Platelet clots resist fibrinolysis by plasminogen activators. We hypothesized that platelet factor XIII may enhance the fibrinolytic resistance of platelet-rich clots by catalyzing the crosslinking of alpha 2-antiplasmin (alpha 2AP) to fibrin. Analysis of plasma clot structure by polyacrylamide gel electrophoresis and immunoblotting revealed accelerated alpha 2AP-fibrin crosslinking in platelet-rich compared with platelet-depleted plasma clots. A similar study of clots formed with purified fibrinogen (depleted of factor XIII activity), isolated platelets, and specific factor XIII inhibitors indicated that this accelerated crosslinking was due to the catalytic activity of platelet factor XIII. Moreover, when washed platelets were aggregated by thrombin, there was evidence of platelet factor XIII-mediated crosslinking between platelet alpha 2AP and platelet fibrin(ogen). Specific inhibition (by a monoclonal antibody) of the alpha 2AP associated with washed platelet aggregates accelerated the fibrinolysis of the platelet aggregate. Thus in platelet-rich plasma clots, and in thrombin-induced platelet aggregates, platelet factor XIII actively formed alpha 2AP-fibrin crosslinks, which appeared to enhance the resistance of platelet-rich clots to fibrinolysis.

  13. Collagen advanced glycation inhibits its Discoidin Domain Receptor 2 (DDR2)-mediated induction of lysyl oxidase in osteoblasts.

    PubMed

    Khosravi, Roozbeh; Sodek, Katharine L; Faibish, Michael; Trackman, Philip C

    2014-01-01

    Diabetes increases the risk of bone fracture. Organic and inorganic bone extracellular matrix components determine bone strength. Previous studies indicate that in diabetes, glycation of collagen causes abnormal arrangements of collagen molecules and fragile bones. Diabetic bone fragility is additionally attributed to reduced levels of lysyl oxidase enzyme-dependent collagen cross-links. The mechanism underlying the presence of lower enzymatic collagen cross-links in diabetic bone has not been directly investigated. Here we determine in primary osteoblast cultures the regulation of lysyl oxidase protein by type I collagen and collagen modified by carboxymethylation (CML-collagen), a form of advanced glycation endproducts. Data indicate that non-glycated collagen up-regulates lysyl oxidase levels both in primary non-differentiated and in differentiating mouse and rat osteoblast cultures, while CML-collagen fails to regulate lysyl oxidase in these cells. Collagen binding to Discoidin Domain Receptor-2 (DDR2) mediates lysyl oxidase increases, determined in DDR2 shRNA knockdown studies. DDR2 binding and activation were disrupted by collagen glycation, pointing to a mechanism for the diminished levels of lysyl oxidase and consequently low lysyl oxidase-derived cross-links in diabetic bone. Our studies indicate that collagen-integrin interactions may not play a major role in up-regulating lysyl oxidase. Furthermore, non-collagenous ligands for the receptor for advanced glycation end products (RAGE) failed to alter lysyl oxidase levels. Taken together with published studies a new understanding emerges in which diabetes- and age-dependent inhibition of normal collagen-stimulated DDR2- and integrin-signaling, and independent advanced glycation-stimulated RAGE-signaling, each contributes to different aspects of diabetic osteopenia. PMID:24120383

  14. Collagen Advanced Glycation Inhibits Its Discoidin Domain Receptor 2 (DDR2)-Mediated Induction of Lysyl Oxidase in Osteoblasts

    PubMed Central

    Khosravi, Roozbeh; Sodek, Katharine L.; Faibish, Michael; Trackman, Philip C.

    2013-01-01

    Diabetes increases the risk of bone fracture. Organic and inorganic bone extracellular matrix components determine bone strength. Previous studies indicate that in diabetes, glycation of collagen causes abnormal arrangements of collagen molecules and fragile bones. Diabetic bone fragility is additionally attributed to reduced levels of lysyl oxidase enzyme-dependent collagen cross-links. The mechanism underlying the presence of lower enzymatic collagen cross-links in diabetic bone has not been directly investigated. Here we determine in primary osteoblast cultures the regulation of lysyl oxidase protein by type I collagen and collagen modified by carboxymethylation (CML-collagen), a form of advanced glycation endproducts. Data indicate that non-glycated collagen up-regulates lysyl oxidase levels both in primary non-differentiated and in differentiating mouse and rat osteoblast cultures, while CML-collagen fails to regulate lysyl oxidase in these cells. Collagen binding to Discoidin Domain Receptor-2 (DDR2) mediates lysyl oxidase increases, determined in DDR2 shRNA knockdown studies. DDR2 binding and activation were disrupted by collagen glycation, pointing to a mechanism for the diminished levels of lysyl oxidase and consequent low lysyl oxidase-derived cross-links in diabetic bone. Our studies indicate that collagen-integrin interactions may not play a major role in up-regulating lysyl oxidase. Furthermore, non-collagenous ligands for the receptor for advanced glycation end products (RAGE) failed to alter lysyl oxidase levels. Taken together with published studies a new understanding emerges in which diabetes- and age-dependent inhibition of normal collagen-stimulated DDR2- and integrin-signaling, and independent advanced glycation-stimulated RAGE-signaling, each contributes to different aspects of diabetic osteopenia. PMID:24120383

  15. Collagen VI related muscle disorders

    PubMed Central

    Lampe, A; Bushby, K

    2005-01-01

    Mutations in the genes encoding collagen VI (COL6A1, COL6A2, and COL6A3) cause Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD), two conditions which were previously believed to be completely separate entities. BM is a relatively mild dominantly inherited disorder characterised by proximal weakness and distal joint contractures. UCMD was originally described as an autosomal recessive condition causing severe muscle weakness with proximal joint contractures and distal hyperlaxity. Here we review the clinical phenotypes of BM and UCMD and their diagnosis and management, and provide an overview of the current knowledge of the pathogenesis of collagen VI related disorders. PMID:16141002

  16. Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy.

    PubMed

    McGuire, J D; Gorski, J P; Dusevich, V; Wang, Y; Walker, M P

    2014-10-01

    The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ

  17. Evaluation of epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes and concerns on osteoblasts.

    PubMed

    Chu, Chenyu; Deng, Jia; Xiang, Lin; Wu, Yingying; Wei, Xiawei; Qu, Yili; Man, Yi

    2016-10-01

    Collagen membranes have ideal biological and mechanical properties for supporting infiltration and proliferation of osteoblasts and play a vital role in guided bone regeneration (GBR). However, pure collagen can lead to inflammation, resulting in progressive bone resorption. Therefore, a method for regulating the level of inflammatory cytokines at surgical sites is paramount for the healing process. Epigallocatechin-3-gallate (EGCG) is a component extracted from green tea with numerous biological activities including an anti-inflammatory effect. Herein, we present a novel cross-linked collagen membrane containing different concentrations of EGCG (0.0064%, 0.064%, and 0.64%) to regulate the level of inflammatory factors secreted by pre-osteoblast cells; improve cell proliferation; and increase the tensile strength, wettability, and thermal stability of collagen membranes. Scanning electron microscope images show that the surfaces of collagen membranes became smoother and the collagen fiber diameters became larger with EGCG treatment. Measurement of the water contact angle demonstrated that introducing EGCG improved membrane wettability. Fourier transform infrared spectroscopy analyses indicated that the backbone of collagen was intact, and the thermal stability was significant improved in differential scanning calorimetry. The mechanical properties of 0.064% and 0.64% EGCG-treated collagen membranes were 1.5-fold greater than those of the control. The extent of cross-linking was significantly increased, as determined by a 2,4,6-trinitrobenzenesulfonic acid solution assay. The Cell Counting Kit-8 (CCK-8) and live/dead assays revealed that collagen membrane cross-linked by 0.0064% EGCG induced greater cell proliferation than pure collagen membranes. Additionally, real-time polymerase chain reaction and enzyme-linked immunosorbent assay results showed that EGCG significantly affected the production of inflammatory factors secreted by MC3T3-E1 cells. Taken together, our

  18. Craniofacial abnormalities in mice carrying a dominant interference mutation in type X collagen.

    PubMed

    Chung, K S; Jacenko, O; Boyle, P; Olsen, B R; Nishimura, I

    1997-04-01

    Type X collagen is a short, non-fibril forming collagen restricted to hypertrophic cartilage, and has been hypothesized to play a role in endochondral ossification. The purpose of the study was to investigate the consequences resulting from the interference of type X collagen function on the growth and development of the craniofacial skeleton through analysis of transgenic mice with a dominant interference mutation for type X collagen. The craniofacial tissues of 21-day-old transgenic mice were examined by: cephalometric and radiographic densitometry analyses, conventional histology, and immunohistochemistry using antibodies specific for either endogenous mouse type X collagen or the transgene product. Genotypically positive mutant mice showed moderate but statistically significant craniofacial skeletal abnormalities, including the underdevelopment of the chondrocranium and mandible, but no cleft palate. Mean radiographic optical densities of the mutant condylar cartilage and the subchondylar areas were 32% less than the corresponding areas of normal mandibles, while mean radiographic optical density measured at the incisor tooth point remained constant. Histologically, transgene-positive mice revealed compressed hypertrophic cartilage zones and reduced trabeculae in both the mandibular condyle and the synchondroses of the chondrocranium. In the normal condyle, mouse type X collagen was localized by the monospecific antibody against a synthetic rat type X collagen NC1 peptide throughout the hypertrophic cartilage layer; in the mutant condyle, immunoreactivity to endogenous type X collagen was only seen sporadically. The truncated type X collagen transgene product, identified with the monoclonal antibody against an epitope within the chick type X collagen NC2 domain, persisted in the lower hypertrophic cartilage layer and the primary spongiosa, rather than being removed by subsequent endochondral ossification. The data suggested that the expression of the chick type

  19. The evolution of fibrillar collagens: a sea-pen collagen shares common features with vertebrate type V collagen.

    PubMed

    Tillet, E; Franc, J M; Franc, S; Garrone, R

    1996-02-01

    The extracellular matrix of marine primitive invertebrates (sponges, polyps and jellyfishes) contains collagen fibrils with narrow diameters. From various data, it has been hypothesized that these primitive collagens could represent ancestral forms of the vertebrate minor collagens, i.e., types V or XI. Recently we have isolated a primitive collagen from the soft tissues of the sea-pen Veretillum cynomorium. This report examines whether the sea-pen collagen shares some features with vertebrate type V collagen. Rotary shadowed images of acid-soluble collagen molecules extracted from beta-APN treated animals, positive staining of segment-long-spacing crystallites precipitated from pepsinized collagen, Western blots of the pepsinized alpha1 and alpha2 chains with antibodies to vertebrate types I, III and V collagens, and in situ gold immunolabeling of ECM collagen fibrils were examined. Our results showed that the tissue form of the sea-pen collagen is a 340-nm threadlike molecule, which is close to the vertebrate type V collagen with its voluminous terminal globular domain, the distribution of most of its polar amino-acid residues, and its antigenic properties. PMID:8653581

  20. Cu,Zn-SOD deficiency induces the accumulation of hepatic collagen.

    PubMed

    Sakiyama, Haruhiko; Fujiwara, Noriko; Yoneoka, Yuka; Yoshihara, Daisaku; Eguchi, Hironobu; Suzuki, Keiichiro

    2016-06-01

    Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic diseases, and results in the development of fibrosis. Oxidative stress is thought to be one of the underlying causes of NAFLD. Copper/zinc superoxide dismutase (SOD1) is a primary antioxidative enzyme that scavenges superoxide anion radicals. Although SOD1 knockout (KO) mice have been reported to develop fatty livers, it is not known whether this lack of SOD1 leads to the development of fibrosis. Since the accumulation of collagen typically precedes liver fibrosis, we assessed the balance between the synthesis and degradation of collagen in liver tissue from SOD1 KO mice. We found a higher accumulation of collagen in the livers of SOD1 KO mice compared to wild type mice. The level of expression of HSP47, a chaperone of collagen, and a tissue inhibitor (TIMP1) of matrix metalloproteinases (a collagen degradating enzyme) was also increased in SOD1 KO mice livers. These results indicate that collagen synthesis is increased but that its degradation is inhibited in SOD1 KO mice livers. Moreover, SOD1 KO mice liver sections were extensively modified by advanced glycation end products (AGEs), which suggest that collagen in SOD1 KO mice liver might be also modified with AGEs and then would be more resistant to the action of collagen degrading enzymes. These findings clearly show that oxidative stress plays an important role in the progression of liver fibrosis. PMID:26981929

  1. Propolis Modifies Collagen Types I and III Accumulation in the Matrix of Burnt Tissue.

    PubMed

    Olczyk, Pawel; Wisowski, Grzegorz; Komosinska-Vassev, Katarzyna; Stojko, Jerzy; Klimek, Katarzyna; Olczyk, Monika; Kozma, Ewa M

    2013-01-01

    Wound healing represents an interactive process which requires highly organized activity of various cells, synthesizing cytokines, growth factors, and collagen. Collagen types I and III, serving as structural and regulatory molecules, play pivotal roles during wound healing. The aim of this study was to compare the propolis and silver sulfadiazine therapeutic efficacy throughout the quantitative and qualitative assessment of collagen types I and III accumulation in the matrix of burnt tissues. Burn wounds were inflicted on pigs, chosen for the evaluation of wound repair because of many similarities between pig and human skin. Isolated collagen types I and III were estimated by the surface plasmon resonance method with a subsequent collagenous quantification using electrophoretic and densitometric analyses. Propolis burn treatment led to enhanced collagens and its components expression, especially during the initial stage of the study. Less expressed changes were observed after silver sulfadiazine (AgSD) application. AgSD and, with a smaller intensity, propolis stimulated accumulation of collagenous degradation products. The assessed propolis therapeutic efficacy, throughout quantitatively and qualitatively analyses of collagen types I and III expression and degradation in wounds matrix, may indicate that apitherapeutic agent can generate favorable biochemical environment supporting reepithelization. PMID:23781260

  2. Transformation of amorphous calcium carbonate to rod-like single crystal calcite via "copying" collagen template.

    PubMed

    Xue, Zhonghui; Hu, Binbin; Dai, Shuxi; Du, Zuliang

    2015-10-01

    Collagen Langmuir films were prepared by spreading the solution of collagen over deionized water, CaCl2 solution and Ca(HCO3)2 solution. Resultant collagen Langmuir monolayers were then compressed to a lateral pressure of 10 mN/m and held there for different duration, allowing the crystallization of CaCO3. The effect of crystallization time on the phase composition and microstructure of CaCO3 was investigated. It was found that amorphous calcium carbonate (ACC) was obtained at a crystallization time of 6 h. The amorphous CaCO3 was transformed to rod-like single crystal calcite crystals at an extended crystallization time of 12 h and 24 h, via "copying" the symmetry and dimensionalities of collagen fibers. Resultant calcite crystallites were well oriented along the longitudinal axis of collagen fibers. The ordered surface structure of collagen fibers and electrostatic interactions played key roles in tuning the oriented nucleation and growth of the calcite crystallites. The mineralized collagen possessing both desired mechanical properties of collagen fiber and good biocompatibility of calcium carbonate may be assembled into an ideal biomaterial for bone implants. PMID:26117783

  3. Mussel adhesive protein provides cohesive matrix for collagen type-1α

    PubMed Central

    Martinez Rodriguez, Nadine R.; Das, Saurabh; Kaufman, Yair; Wei, Wei; Israelachvili, Jacob N.; Waite, J. Herbert

    2015-01-01

    Understanding the interactions between collagen and adhesive mussel foot proteins (mfps) can lead to improved medical and dental adhesives, particularly for collagen-rich tissues. Here we investigated interactions between collagen type-1, the most abundant loadbearing animal protein, and mussel foot protein-3 (mfp-3) using a quartz crystal microbalance and surface forces apparatus (SFA). Both hydrophilic and hydrophobic variants of mfp-3 were exploited to probe the nature of the interaction between the protein and collagen. Our chief findings are: 1) mfp-3 is an effective chaperone for tropocollagen adsorption to TiO2 and mica surfaces; 2) at pH 3, collagen addition between two mfp-3 films (Wc = 5.4 ± 0.2 mJ/m2) increased their cohesion by nearly 35%; 3) oxidation of Dopa in mfp-3 by periodate did not abolish the adhesion between collagen and mfp-3 films, and 4) collagen bridging between both hydrophilic and hydrophobic mfp-3 variant films is equally robust, suggesting that hydrophobic interactions play a minor role. Extensive H-bonding, π-cation and electrostatic interactions are more plausible to explain the reversible bridging of mfp-3 films by collagen. PMID:25770997

  4. A graphene oxide-based FRET sensor for rapid and specific detection of unfolded collagen fragments.

    PubMed

    Sun, Xiuxia; Fan, Jun; Zhang, Yuping; Chen, Hongli; Zhao, Yongqing; Xiao, Jianxi

    2016-05-15

    The unstructured collagen species plays a critical role in a variety of important biological processes as well as pathological conditions. In order to develop novel diagnosis and therapies for collagen-related diseases, it is essential to construct simple and efficient methods to detect unfolded collagen fragments. We therefore have designed a FITC-labeled collagen mimic triple helical peptide, whose adsorption on the surface of GO effectively quenches its fluorescence. The newly constructed GO/FITC-GPO complex specifically detects unstructured collagen fragments, but not fully folded triple helix species. The detection shows a clear preference for the collagen targets with complementary GPO-rich sequences. The conformation-sensitive, sequence-specific GO-based approach can be applied as an efficient biosensor for rapid detection of unfolded collagen fragments at nM level, and may have great potential in drug screening for inhibitors of unfolded collagen. It may provide a prototype to develop GO-based assays to detect other important unstructured proteins involved in diseases. PMID:26686918

  5. Mussel adhesive protein provides cohesive matrix for collagen type-1α.

    PubMed

    Martinez Rodriguez, Nadine R; Das, Saurabh; Kaufman, Yair; Wei, Wei; Israelachvili, Jacob N; Waite, J Herbert

    2015-05-01

    Understanding the interactions between collagen and adhesive mussel foot proteins (mfps) can lead to improved medical and dental adhesives, particularly for collagen-rich tissues. Here we investigated interactions between collagen type-1, the most abundant load-bearing animal protein, and mussel foot protein-3 (mfp-3) using a quartz crystal microbalance and surface forces apparatus (SFA). Both hydrophilic and hydrophobic variants of mfp-3 were exploited to probe the nature of the interaction between the protein and collagen. Our chief findings are: 1) mfp-3 is an effective chaperone for tropocollagen adsorption to TiO2 and mica surfaces; 2) at pH 3, collagen addition between two mfp-3 films (Wc = 5.4 ± 0.2 mJ/m(2)) increased their cohesion by nearly 35%; 3) oxidation of Dopa in mfp-3 by periodate did not abolish the adhesion between collagen and mfp-3 films, and 4) collagen bridging between both hydrophilic and hydrophobic mfp-3 variant films is equally robust, suggesting that hydrophobic interactions play a minor role. Extensive H-bonding, π-cation and electrostatic interactions are more plausible to explain the reversible bridging of mfp-3 films by collagen. PMID:25770997

  6. Fibroblast-Derived MMP-14 Regulates Collagen Homeostasis in Adult Skin.

    PubMed

    Zigrino, Paola; Brinckmann, Jürgen; Niehoff, Anja; Lu, Yinhui; Giebeler, Nives; Eckes, Beate; Kadler, Karl E; Mauch, Cornelia

    2016-08-01

    Proteolytic activities in the extracellular matrix by the matrix metalloproteinase (MMP)-14 have been implicated in the remodeling of collagenous proteins during development. To analyze the function of fibroblast-derived MMP-14 in adult skin homeostasis, we generated mice with inducible deletion of MMP-14 in the dermal fibroblast (MMP-14(Sf-/-)). These mice are smaller and display a fibrosis-like phenotype in the skin. The skin of these mice showed increased stiffness and tensile strength but no altered collagen cross-links. In vivo, we measured a significantly increased amount of collagen type I accumulated in the skin of MMP-14(Sf-/-) mice without an increase in collagen fibril diameters. However, bleomycin-induced fibrosis in skin proceeded in a comparable manner in MMP-14(Sf+/+) and MMP-14(Sf-/-) mice, but resolution over time was impaired in MMP-14(Sf-/-) mice. Increased accumulation of collagen type I was detected in MMP-14(Sf-/-) fibroblasts in culture without significant enhancement of collagen de novo synthesis. This points to a degradative but not synthetic phenotype. In support of this, MMP-14(Sf-/-) fibroblasts lost their ability to process fibrillar collagen type I and to activate proMMP-2. Taken together, these data indicate that MMP-14 expression in fibroblasts plays a crucial role in collagen remodeling in adult skin and largely contributes to dermal homeostasis underlying its pathogenic role in fibrotic skin disease. PMID:27066886

  7. Secretion and assembly of type IV and VI collagens depend on glycosylation of hydroxylysines.

    PubMed

    Sipilä, Laura; Ruotsalainen, Heli; Sormunen, Raija; Baker, Naomi L; Lamandé, Shireen R; Vapola, Miia; Wang, Chunguang; Sado, Yoshikazu; Aszodi, Attila; Myllylä, Raili

    2007-11-16

    Most lysines in type IV and VI collagens are hydroxylated and glycosylated, but the functions of these unique galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues are poorly understood. The formation of glycosylated hydroxylysines is catalyzed by multifunctional lysyl hydroxylase 3 (LH3) in vivo, and we have used LH3-manipulated mice and cells as models to study the function of these carbohydrates. These hydroxylysine-linked carbohydrates were shown recently to be indispensable for the formation of basement membranes (Ruotsalainen, H., Sipilä, L., Vapola, M., Sormunen, R., Salo, A. M., Uitto, L., Mercer, D. K., Robins, S. P., Risteli, M., Aszodi, A., Fässler, R., and Myllylä, R. (2006) J. Cell Sci. 119, 625-635). Analysis of LH3 knock-out embryos and cells in this work indicated that loss of glycosylated hydroxylysines prevents the intracellular tetramerization of type VI collagen and leads to impaired secretion of type IV and VI collagens. Mice lacking the LH activity of LH3 produced slightly underglycosylated type IV and VI collagens with abnormal distribution. The altered distribution and aggregation of type VI collagen led to similar ultrastructural alterations in muscle to those detected in collagen VI knockout and some Ullrich congenital muscular dystrophy patients. Our results provide new information about the function of hydroxylysine-linked carbohydrates of collagens, indicating that they play an important role in the secretion, assembly, and distribution of highly glycosylated collagen types. PMID:17873278

  8. Biology, chemistry and pathology of collagen

    SciTech Connect

    Fleischmajer, R.; Olsen, B.R.; Kuhn, K.

    1985-01-01

    This book consists of five parts and a section of poster papers. Some of the articles are: Structure of the Type II Collagen Gene; Structural and Functional Analysis of the Genes for ..cap alpha..2(1) and ..cap alpha..1(III) collagens; Structure and Expression of the Collagen Genes of C. Elegans; Molecular Basis of Clinical Heterogeneity in the Ehlers-Danlos Syndrome; and Normal and Mutant Human Collagen Genes.

  9. Phospholipase D1 decreases type I collagen levels in hepatic stellate cells via induction of autophagy.

    PubMed

    Seo, H-Y; Jang, B-K; Jung, Y-A; Lee, E-J; Kim, H-S; Jeon, J-H; Kim, J-G; Lee, I-K; Kim, M-K; Park, K-G

    2014-06-20

    Hepatic stellate cells (HSCs) are major players in liver fibrogenesis. Accumulating evidence shows that suppression of autophagy plays an important role in the development and progression of liver disease. Phospholipase D1 (PLD1), which catalyzes the hydrolysis of phosphatidylcholine to yield phosphatidic acid (PA) and choline, was recently shown to modulate autophagy. However, little is known about the effects of PLD1 on the production of type I collagen that characterizes liver fibrosis. Here, we examined whether PLD1 regulates type I collagen levels in HSCs through induction of autophagy. Adenovirus-mediated overexpression of PLD-1 (Ad-PLD1) reduced type I collagen levels in the activated human HSC lines, hTERT and LX2. Overexpression of PLD1 in HSCs led to induction of autophagy as demonstrated by increased LC3-II conversion and formation of LC3 puncta, and decreased p62 abundance. Moreover, inhibiting the induction of autophagy by treating cells with bafilomycin or a small interfering (si)RNA for ATG7 rescued Ad-PLD1-induced suppression of type I collagen accumulation in HSCs. The effects of PLD on type I collagen levels were not related to TGF-β/Smad signaling. Furthermore, treatment of cells with PA induced autophagy and inhibited type I collagen accumulation. The present study indicates that PLD1 plays a role in regulating type I collagen accumulation through induction of autophagy. PMID:24802400

  10. Micromechanical analysis of native and cross-linked collagen type I fibrils supports the existence of microfibrils.

    PubMed

    Yang, L; van der Werf, K O; Dijkstra, P J; Feijen, J; Bennink, M L

    2012-02-01

    The mechanical properties of individual collagen fibrils of approximately 200 nm in diameter were determined using a slightly adapted AFM system. Single collagen fibrils immersed in PBS buffer were attached between an AFM cantilever and a glass surface to perform tensile tests at different strain rates and stress relaxation measurements. The stress-strain behavior of collagen fibrils immersed in PBS buffer comprises a toe region up to a stress of 5 MPa, followed by the heel and linear region at higher stresses. Hysteresis and strain-rate dependent stress-strain behavior of collagen fibrils were observed, which suggest that single collagen fibrils have viscoelastic properties. The stress relaxation process of individual collagen fibrils could be best fitted using a two-term Prony series. Furthermore, the influence of different cross-linking agents on the mechanical properties of single collagen fibrils was investigated. Based on these results, we propose that sliding of microfibrils with respect to each other plays a role in the viscoelastic behavior of collagen fibrils in addition to the sliding of collagen molecules with respect to each other. Our finding provides a better insight into the relationship between the structure and mechanical properties of collagen and the micro-mechanical behavior of tissues. PMID:22301184

  11. Exposure to Mimivirus Collagen Promotes Arthritis

    PubMed Central

    Shah, Nikunj; Hülsmeier, Andreas J.; Hochhold, Nina; Neidhart, Michel; Gay, Steffen

    2014-01-01

    Collagens, the most abundant proteins in animals, also occur in some recently described nucleocytoplasmic large DNA viruses such as Mimiviridae, which replicate in amoebae. To clarify the impact of viral collagens on the immune response of animals exposed to Mimiviridae, we have investigated the localization of collagens in Acanthamoeba polyphaga mimivirus particles and the response of mice to immunization with mimivirus particles. Using protein biotinylation, we have first shown that viral collagen encoded by open reading frame L71 is present at the surface of mimivirus particles. Exposure to mimivirus collagens elicited the production of anti-collagen antibodies in DBA/1 mice immunized intradermally with mimivirus protein extracts. This antibody response also targeted mouse collagen type II and was accompanied by T-cell reactivity to collagen and joint inflammation, as observed in collagen-induced arthritis following immunization of mice with bovine collagen type II. The broad distribution of nucleocytoplasmic large DNA viruses in the environment suggests that humans are constantly exposed to such large virus particles. A survey of blood sera from healthy human subjects and from rheumatoid arthritis patients indeed demonstrated that 30% of healthy-subject and 36% of rheumatoid arthritis sera recognized the major mimivirus capsid protein L425. Moreover, whereas 6% of healthy-subject sera recognized the mimivirus collagen protein L71, 22% of rheumatoid arthritis sera were positive for mimivirus L71. Accordingly, our study shows that environmental exposure to mimivirus represents a risk factor in triggering autoimmunity to collagens. PMID:24173233

  12. Biomimetic Analogs for Collagen Biomineralization

    PubMed Central

    Gu, L.; Kim, Y.K.; Liu, Y.; Ryou, H.; Wimmer, C.E.; Dai, L.; Arola, D.D.; Looney, S.W.; Pashley, D.H.; Tay, F.R.

    2011-01-01

    Inability of chemical phosphorylation of sodium trimetaphosphate to induce intrafibrillar mineralization of type I collagen may be due to the failure to incorporate a biomimetic analog to stabilize amorphous calcium phosphates (ACP) as nanoprecursors. This study investigated adsorption/desorption characteristics of hydrolyzed and pH-adjusted sodium trimetaphosphate (HPA-Na3P3O9) to collagen. Based on those results, a 5-minute treatment time with 2.8 wt% HPA-Na3P3O9 was used in a single-layer reconstituted collagen model to confirm that both the ACP-stabilization analog and matrix phosphoprotein analog must be present for intrafibrillar mineralization. The results of that model were further validated by complete remineralization of phosphoric-acid-etched dentin treated with the matrix phosphoprotein analog and lined with a remineralizing lining composite, and with the ACP-stabilization analog supplied in simulated body fluid. An understanding of the basic processes involved in intrafibrillar mineralization of reconstituted collagen fibrils facilitates the design of novel tissue engineering materials for hard tissue repair and regeneration. PMID:20940362

  13. Associations of the β-Fibrinogen Hae III and Factor XIII Val34Leu Gene Variants with Venous Thrombosis

    PubMed Central

    Cushman, Mary; Cornell, Alexandra; Folsom, Aaron R.; Wang, Lu; Tsai, Michael Y.; Polak, Joseph; Tang, Zhonghua

    2008-01-01

    Introduction The factor XIII Val34Leu (100 G→T) and β-fibrinogen Hae III (-455 G→A) gene variants have been associated with reduced risk of venous thrombosis, but not in all studies. Methods We investigated the associations of these polymorphisms with risk of venous thrombosis in a prospective, population-based study of 21,680 men and women aged 45–100 years at enrollment. Factor XIII 100 G/T and β-fibrinogen -455 G/A were analyzed on stored DNA from 511 thrombosis cases and 1028 control subjects without thrombosis during follow up. Results The β-fibrinogen A allele was present in 24.4% of cases and 32.3% of controls. Compared to GG subjects, the age, race, and sex adjusted odds ratio (OR) of venous thrombosis was 0.77 (95% CI 0.59–0.99) for GA subjects, and 0.60 (95% CI 0.31–1.16) for AA subjects. The adjusted OR of thrombosis associated with factor XIII 100 G/T was 1.01 (95% CI 0.81–1.26) for GT subjects and 0.45 (95% CI 0.44–1.19) for TT subjects, compared to GG. For both genotypes, ORs of thrombosis were similar in whites and non-whites, although there were no non-white fibrinogen AA cases. β-Fibrinogen -455GA or AA attenuated the thrombosis risk associated with obesity (from 2.14 to 1.25) and factor V Leiden (from 3.89 to 2.36). Conclusions β-fibrinogen -455 G/A, but not factor XIII 100 G/T, was associated with a lower risk of venous thrombosis in this general population sample. β-Fibrinogen -455A may attenuate the increased thrombosis risk associated with obesity or factor V Leiden. PMID:17582472

  14. Play Therapy: A Review

    ERIC Educational Resources Information Center

    Porter, Maggie L.; Hernandez-Reif, Maria; Jessee, Peggy

    2009-01-01

    This article discusses the current issues in play therapy and its implications for play therapists. A brief history of play therapy is provided along with the current play therapy approaches and techniques. This article also touches on current issues or problems that play therapists may face, such as interpreting children's play, implementing…

  15. Lumican Deficiency Results In Cardiomyocyte Hypertrophy With Altered Collagen Assembly

    PubMed Central

    Dupuis, Loren E.; Berger, Matthew G.; Feldman, Samuel; Doucette, Lorna; Fowlkes, Vennece; Chakravarti, Shukti; Thibaudeau, Sarah; Alcala, Nicolas E.; Bradshaw, Amy D.; Kern, Christine B.

    2015-01-01

    The ability of the heart to adapt to increased stress is dependent on modification of its extracellular matrix (ECM) architecture that is established during postnatal development as cardiomyocytes differentiate, a process that is poorly understood. We hypothesized that the small leucine-rich proteoglycan (SLRP) lumican (LUM), which binds collagen and facilitates collagen assembly in other tissues, may play a critical role in establishing the postnatal murine myocardial ECM. Although previous studies suggest LUM deficient mice (lum−/−) exhibit skin anomalies consistent with Ehlers-Danlos syndrome, lum−/− hearts have not been evaluated. These studies show LUM was immunolocalized to non-cardiomyocytes of the cardiac ventricles and its expression increased throughout development. Lumican deficiency resulted in significant (50%) perinatal death and further examination of the lum−/− neonatal hearts revealed an increase in myocardial tissue without a significant increase in cell proliferation. However cardiomyocytes from surviving postnatal day 0 (P0), 1 month (1 mo) and adult (4 mo) lum−/− hearts were significantly larger than their wild type (WT) littermates. Immunohistochemistry revealed that the increased cardiomyocyte size in the lum−/− hearts correlated with alteration of the cardiomyocyte pericellular ECM components collagenα1(I) and the class I SLRP decorin (DCN). Western blot analysis demonstrated that the ratio of glycosaminoglycan (GAG) decorated DCN to core DCN was reduced in P0 and 1 mo lum−/− hearts. There was also a reduction in the β and γ forms of collagenα1(I) in lum−/− hearts. While the total insoluble collagen content was significantly reduced, the fibril size was increased in lum−/− hearts, indicating LUM may play a role in collagen fiber stability and lateral fibril assembly. These results suggest that LUM controls cardiomyocyte growth by regulating the pericellular ECM and also indicates that LUM may coordinate

  16. Collagen VI and Hyaluronan: The Common Role in Breast Cancer

    PubMed Central

    Karousou, Evgenia; D'Angelo, Maria Luisa; Kouvidi, Katerina; Vigetti, Davide; Viola, Manuela; Passi, Alberto

    2014-01-01

    Collagen VI and hyaluronan are widely distributed extracellular matrix macromolecules that play a crucial role in tissue development and are highly expressed in cancers. Both hyaluronan and collagen VI are upregulated in breast cancer, generating a microenvironment that promotes tumour progression and metastasis. A growing number of studies show that these two molecules are involved in inflammation and angiogenesis by recruiting macrophages and endothelial cells, respectively. Additionally, collagen VI induces epithelial-mesenchymal transition that is correlated to increased synthesis of hyaluronan in mammary cells. Hyaluronan has also a specific role in cellular functions that depends mainly on the size of the polymer, whereas the effect of collagen VI in tumour progression may be the result of the intact molecule or the C5 peptide of α3(VI) chain, known as endotrophin. Collectively, these findings strongly support the parallel role of these molecules in tumour progression and suggest that they may be used as prognostic factors for the breast cancer treatment. PMID:25126569

  17. Matrix metalloproteinase 9 modulates collagen matrices and wound repair

    PubMed Central

    LeBert, Danny C.; Squirrell, Jayne M.; Rindy, Julie; Broadbridge, Elizabeth; Lui, Yuming; Zakrzewska, Anna; Eliceiri, Kevin W.; Meijer, Annemarie H.; Huttenlocher, Anna

    2015-01-01

    Acute and chronic injuries are characterized by leukocyte infiltration into tissues. Although matrix metalloproteinase 9 (Mmp9) has been implicated in both conditions, its role in wound repair remains unclear. We previously reported a zebrafish chronic inflammation mutant caused by an insertion in the hepatocyte growth factor activator inhibitor gene 1 (hai1; also known as spint1) that is characterized by epithelial extrusions and neutrophil infiltration into the fin. Here, we performed a microarray analysis and found increased inflammatory gene expression in the mutant larvae, including a marked increase in mmp9 expression. Depletion of mmp9 partially rescued the chronic inflammation and epithelial phenotypes, in addition to restoring collagen fiber organization, as detected by second-harmonic generation imaging. Additionally, we found that acute wounding induces epithelial cell mmp9 expression and is associated with a thickening of collagen fibers. Interestingly, depletion of mmp9 impaired this collagen fiber reorganization. Moreover, mmp9 depletion impaired tissue regeneration after tail transection, implicating Mmp9 in acute wound repair. Thus, Mmp9 regulates both acute and chronic tissue damage and plays an essential role in collagen reorganization during wound repair. PMID:26015541

  18. Collagen interactions: Drug design and delivery.

    PubMed

    An, Bo; Lin, Yu-Shan; Brodsky, Barbara

    2016-02-01

    Collagen is a major component in a wide range of drug delivery systems and biomaterial applications. Its basic physical and structural properties, together with its low immunogenicity and natural turnover, are keys to its biocompatibility and effectiveness. In addition to its material properties, the collagen triple-helix interacts with a large number of molecules that trigger biological events. Collagen interactions with cell surface receptors regulate many cellular processes, while interactions with other ECM components are critical for matrix structure and remodeling. Collagen also interacts with enzymes involved in its biosynthesis and degradation, including matrix metalloproteinases. Over the past decade, much information has been gained about the nature and specificity of collagen interactions with its partners. These studies have defined collagen sequences responsible for binding and the high-resolution structures of triple-helical peptides bound to its natural binding partners. Strategies to target collagen interactions are already being developed, including the use of monoclonal antibodies to interfere with collagen fibril formation and the use of triple-helical peptides to direct liposomes to melanoma cells. The molecular information about collagen interactions will further serve as a foundation for computational studies to design small molecules that can interfere with specific interactions or target tumor cells. Intelligent control of collagen biological interactions within a material context will expand the effectiveness of collagen-based drug delivery. PMID:26631222

  19. Go natural and smarter: fenugreek as a hydration designer of collagen based biomaterials.

    PubMed

    Kanungo, Ivy; Fathima, Nishter Nishad; Jonnalagadda, Raghava Rao; Nair, Balachandran Unni

    2015-01-28

    Collagen-based biomaterials have received considerable attention for smarter biomedical applications due to their inherent superior mechano-biological properties. However, accumulating evidence suggests that water, as a probe liquid bound in collagen, might be investigated to explore the influence of additives on the static and dynamic solvation behavior of collagen. The structure and dynamics of water near the surface/interface of collagen-fenugreek composites were demonstrated via circular dichroic spectroscopy, thermoporometry and impedimetric measurements to enlighten about the configuration-function relationship of collagen. Thermodynamic parameters of the composites signify the fenugreek concentration dependent structural robustness of collagen. Thermodynamic parameters such as free energies for unfolding, enthalpies, entropies and activation energies indicate that the residual structure modulates the stability of the denatured state up to 22 kcal mol(-1) and the parameters correlate with structural data for collagen complexed with fenugreek. The association constant of fenugreek is found to be 0.5807 M(-1). The binding of fenugreek influences rearrangement of the collagen-water network, resulting in the transition from a disordered (high entropy) unbound state to a structured (lower entropy) bound state. Fenugreek concentration plays a crucial role in shaping up the free energy that governs the folding, structure and stability of collagen. Dielectric data emphasize the effect of hydrophobic and hydrophilic clusters on the side chain motion constraints. The thermoporometry technique probes the pore size distributions of the composites. These methods provide insights into the role of excluded volume, chain stiffness and stability of a new collagen-galactomannan based composite, expanding its utility in "smart biomaterial applications". PMID:25502597

  20. HST/WFPC2 imaging of the dwarf satellites And XI and And XIII: horizontal branch morphology and RR Lyraes

    NASA Astrophysics Data System (ADS)

    Yang, S.-C.; Sarajedini, A.

    2012-01-01

    We present a study of the stellar populations in two faint M31 dwarf satellites, Andromeda XI and Andromeda XIII. Using archival images from the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope, we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new template light-curve fitting routine [Robust RR Lyrae light curve FITing (RRFIT)] has been used to detect and characterize RRL populations in both galaxies. The mean periods of RRab (RR0) stars in And XI and And XIII are = 0.621 ± 0.026 (error1) ± 0.022 (error2) and 0.648 ± 0.026 (error1) ± 0.022 (error2), respectively, where 'error1' represents the standard error of the mean, while 'error2' is based on our synthetic light-curve simulations. The RRL populations in these galaxies show a lack of RRab stars with high amplitudes [Amp (V) > 1.0 mag] and relatively short periods (? d), yet their period-V-band amplitude [P- Amp (V)] relations track the relation defined by the M31 field halo RRL populations at ˜11 kpc from the centre of M31. The metallicities of the RRab stars are calculated via a relationship between [Fe/H], log Pab and Amp(V). The resultant abundances ([ Fe/H ]And XI=-1.75; [ Fe/H ]And XIII=-1.74) are consistent with the values calculated from the red giant branch slope, indicating that our measurements are not significantly affected by RRL evolutionary away from the zero-age HB. The distance to each galaxy, based on the absolute V magnitudes of the RRab stars, is (m-M)0, V= 24.33 ± 0.05 for And XI and (m-M)0, V= 24.62 ± 0.05 for And XIII. We discuss the origins of And XI and And XIII based on a comparative analysis of the luminosity-metallicity relation of Local Group dwarf galaxies. Based on observations taken with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute.

  1. Collagen scaffolds combined with collagen-binding ciliary neurotrophic factor facilitate facial nerve repair in mini-pigs.

    PubMed

    Lu, Chao; Meng, Danqing; Cao, Jiani; Xiao, Zhifeng; Cui, Yi; Fan, Jingya; Cui, Xiaolong; Chen, Bing; Yao, Yao; Zhang, Zhen; Ma, Jinling; Pan, Juli; Dai, Jianwu

    2015-05-01

    The preclinical studies using animal models play a very important role in the evaluation of facial nerve regeneration. Good models need to recapitulate the distance and time for axons to regenerate in humans. Compared with the most used rodent animals, the structure of facial nerve in mini-pigs shares more similarities with humans in microanatomy. To evaluate the feasibility of repairing facial nerve defects by collagen scaffolds combined with ciliary neurotrophic factor (CNTF), 10-mm-long gaps were made in the buccal branch of mini-pigs' facial nerve. Three months after surgery, electrophysiological assessment and histological examination were performed to evaluate facial nerve regeneration. Immunohistochemistry and transmission electron microscope observation showed that collagen scaffolds with collagen binding (CBD)-CNTF could promote better axon regeneration, Schwann cell migration, and remyelination at the site of implant device than using scaffolds alone. Electrophysiological assessment also showed higher recovery rate in the CNTF group. In summary, combination of collagen scaffolds and CBD-CNTF showed promising effects on facial nerve regeneration in mini-pig models. PMID:25098760

  2. Immunostimulation effect of jellyfish collagen.

    PubMed

    Sugahara, Takuya; Ueno, Masashi; Goto, Yoko; Shiraishi, Ryusuke; Doi, Mikiharu; Akiyama, Koichi; Yamauchi, Satoshi

    2006-09-01

    Certain edible large jellyfishes belonging to the order Rhizostomeae are consumed in large quantities in China and Japan. The exumbrella part of the edible jellyfish Stomolophus nomurai was cut and soaked in dilute hydrochloric acid solution (pH 3.0) for 12 h, and heated at 121 degrees C for 20 min. The immunostimulation effects of the jellyfish extract were examined. The jellyfish extract enhanced IgM production of human hybridoma HB4C5 cells 34-fold. IgM and IgG production of human peripheral blood lymphocytes (PBL) were also accelerated, 2.8- and 1.4-fold respectively. Moreover, production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by human PBL was stimulated 100- and 17-fold respectively. Collagenase treatment inactivated the immunostimulation activity of the jellyfish extract. In addition, purified collagen from bovine Achilles' tendon accelerated IgM production of hybridoma cells. These facts mean that collagen has an immunostimulation effect, and that the active substance in jellyfish extract is collagen. PMID:16960386

  3. The Denial of Play.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Well meaning parents and teachers often use children's play for the purposes of literacy and socialization. Yet, these attempts may deny play to children by subordinating play to some other concept. Evidence shows that even when parents play with their very young children they generally play games like shopping, cooking, and eating; whereas when…

  4. Factor XIII B Subunit Polymorphisms and the Risk of Coronary Artery Disease

    PubMed Central

    Mezei, Zoltán A.; Bereczky, Zsuzsanna; Katona, Éva; Gindele, Réka; Balogh, Emília; Fiatal, Szilvia; Balogh, László; Czuriga, István; Ádány, Róza; Édes, István; Muszbek, László

    2015-01-01

    The aim of the case-control study was to explore the effect of coagulation factor XIII (FXIII) B subunit (FXIII-B) polymorphisms on the risk of coronary artery disease, and on FXIII levels. In the study, 687 patients admitted for coronary angiography to investigate suspected coronary artery disease and 994 individuals representing the Hungarian population were enrolled. The patients were classified according to the presence of significant coronary atherosclerosis (CAS) and history of myocardial infarction (MI). The F13B gene was genotyped for p.His95Arg and for intron K nt29756 C>G polymorphisms; the latter results in the replacement of 10 C-terminal amino acids by 25 novel amino acids. The p.His95Arg polymorphism did not influence the risk of CAS or MI. The FXIII-B intron K nt29756 G allele provided significant protection against CAS and MI in patients with a fibrinogen level in the upper tertile. However, this effect prevailed only in the presence of the FXIII-A Leu34 allele, and a synergism between the two polymorphisms was revealed. Carriers of the intron K nt29756 G allele had significantly lower FXIII levels, and FXIII levels in the lower tertile provided significant protection against MI. It is suggested that the protective effect of the combined polymorphisms is related to decreased FXIII levels. PMID:25569091

  5. Revisiting the mechanism of coagulation factor XIII activation and regulation from a structure/functional perspective

    PubMed Central

    Gupta, Sneha; Biswas, Arijit; Akhter, Mohammad Suhail; Krettler, Christoph; Reinhart, Christoph; Dodt, Johannes; Reuter, Andreas; Philippou, Helen; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2016-01-01

    The activation and regulation of coagulation Factor XIII (FXIII) protein has been the subject of active research for the past three decades. Although discrete evidence exists on various aspects of FXIII activation and regulation a combinatorial structure/functional view in this regard is lacking. In this study, we present results of a structure/function study of the functional chain of events for FXIII. Our study shows how subtle chronological submolecular changes within calcium binding sites can bring about the detailed transformation of the zymogenic FXIII to its activated form especially in the context of FXIIIA and FXIIIB subunit interactions. We demonstrate what aspects of FXIII are important for the stabilization (first calcium binding site) of its zymogenic form and the possible modes of deactivation (thrombin mediated secondary cleavage) of the activated form. Our study for the first time provides a structural outlook of the FXIIIA2B2 heterotetramer assembly, its association and dissociation. The FXIIIB subunits regulatory role in the overall process has also been elaborated upon. In summary, this study provides detailed structural insight into the mechanisms of FXIII activation and regulation that can be used as a template for the development of future highly specific therapeutic inhibitors targeting FXIII in pathological conditions like thrombosis. PMID:27453290

  6. Pulsational frequencies of the eclipsing δ Scuti star HD 172189. Results of the STEPHI XIII campaign

    NASA Astrophysics Data System (ADS)

    Costa, J. E. S.; Michel, E.; Peña, J.; Creevey, O.; Li, Z. P.; Chevreton, M.; Belmonte, J. A.; Alvarez, M.; Fox Machado, L.; Parrao, L.; Pérez Hernández, F.; Fernández, A.; Fremy, J. R.; Pau, S.; Alonso, R.

    2007-06-01

    Context: The eclipsing δ Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. Aims: The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models. Methods: We performed a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign. Results: We have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level of 65%, in the range between 100-300 μHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system. Table 1 is only available in electronic form at http://www.aanda.org

  7. Impaired Activity of Blood Coagulant Factor XIII in Patients with Necrotizing Enterocolitis

    PubMed Central

    Tao, Guo-Zhong; Liu, Bo; Zhang, Rong; Liu, Gigi; Abdullah, Fizan; Harris, Mary Cay; Brandt, Mary L.; Ehrenkranz, Richard A.; Bowers, Corinna; Martin, Camilia R.; Moss, R. Lawrence; Sylvester, Karl G.

    2015-01-01

    Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) medical/surgical emergency of the newborn and a leading cause of preterm neonate morbidity and mortality. NEC is a challenge to diagnose since it often shares similar clinical features with neonatal sepsis. In the present study, plasma protein profiling was compared among NEC, sepsis and control cohorts using gel electrophoresis, immunoblot and mass spectrometry. We observed significant impairment in the formation of fibrinogen-γ dimers (FGG-dimer) in the plasma of newborns with NEC that could efficiently differentiate NEC and sepsis with a high level of sensitivity and specificity. Interestingly, the impaired FGG-dimer formation could be restored in NEC plasma by the addition of exogenous active factor XIII (FXIII). Enzymatic activity of FXIII was determined to be significantly lower in NEC subject plasma for crosslinking FGG when compared to sepsis. These findings demonstrate a potential novel biomarker and related biologic mechanism for diagnosing NEC, as well as suggest a possible therapeutic strategy. PMID:26277871

  8. Revisiting the mechanism of coagulation factor XIII activation and regulation from a structure/functional perspective.

    PubMed

    Gupta, Sneha; Biswas, Arijit; Akhter, Mohammad Suhail; Krettler, Christoph; Reinhart, Christoph; Dodt, Johannes; Reuter, Andreas; Philippou, Helen; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2016-01-01

    The activation and regulation of coagulation Factor XIII (FXIII) protein has been the subject of active research for the past three decades. Although discrete evidence exists on various aspects of FXIII activation and regulation a combinatorial structure/functional view in this regard is lacking. In this study, we present results of a structure/function study of the functional chain of events for FXIII. Our study shows how subtle chronological submolecular changes within calcium binding sites can bring about the detailed transformation of the zymogenic FXIII to its activated form especially in the context of FXIIIA and FXIIIB subunit interactions. We demonstrate what aspects of FXIII are important for the stabilization (first calcium binding site) of its zymogenic form and the possible modes of deactivation (thrombin mediated secondary cleavage) of the activated form. Our study for the first time provides a structural outlook of the FXIIIA2B2 heterotetramer assembly, its association and dissociation. The FXIIIB subunits regulatory role in the overall process has also been elaborated upon. In summary, this study provides detailed structural insight into the mechanisms of FXIII activation and regulation that can be used as a template for the development of future highly specific therapeutic inhibitors targeting FXIII in pathological conditions like thrombosis. PMID:27453290

  9. Abnormal Compartmentalization of Cartilage Matrix Components in Mice Lacking Collagen X: Implications for Function

    PubMed Central

    Kwan, Kin Ming; Pang, Michael K.M.; Zhou, Sheila; Cowan, Soot Keng; Kong, Richard Y.C.; Pfordte, Tim; Olsen, Bjorn R.; Sillence, David O.; Tam, Patrick P.L.; Cheah, Kathryn S.E.

    1997-01-01

    There are conflicting views on whether collagen X is a purely structural molecule, or regulates bone mineralization during endochondral ossification. Mutations in the human collagen α1(X) gene (COL10A1) in Schmid metaphyseal chondrodysplasia (SMCD) suggest a supportive role. But mouse collagen α1(X) gene (Col10a1) null mutants were previously reported to show no obvious phenotypic change. We have generated collagen X deficient mice, which shows that deficiency does have phenotypic consequences which partly resemble SMCD, such as abnormal trabecular bone architecture. In particular, the mutant mice develop coxa vara, a phenotypic change common in human SMCD. Other consequences of the mutation are reduction in thickness of growth plate resting zone and articular cartilage, altered bone content, and atypical distribution of matrix components within growth plate cartilage. We propose that collagen X plays a role in the normal distribution of matrix vesicles and proteoglycans within the growth plate matrix. Collagen X deficiency impacts on the supporting properties of the growth plate and the mineralization process, resulting in abnormal trabecular bone. This hypothesis would accommodate the previously conflicting views of the function of collagen X and of the molecular pathogenesis of SMCD. PMID:9015315

  10. The Staphylococcus aureus collagen adhesin is a virulence determinant in experimental septic arthritis.

    PubMed Central

    Patti, J M; Bremell, T; Krajewska-Pietrasik, D; Abdelnour, A; Tarkowski, A; Rydén, C; Höök, M

    1994-01-01

    The importance of a collagen-binding adhesin in the pathogenesis of septic arthritis has been examined by comparing the virulence of two sets of Staphylococcus aureus mutants in an animal model. Collagen adhesin-negative mutant PH100 was constructed by replacing the chromosomal collagen adhesin gene (cna) in a clinical strain, Phillips, with an inactivated copy of the gene. Collagen adhesin-positive mutant S. aureus CYL574 was generated by introducing the cna gene into CYL316, a strain that normally lacks the cna gene. Biochemical, immunological, and functional analyses of the generated mutants and their respective parent strains showed that binding of 125I-labeled collagen, expression of an immunoreactive collagen adhesin, and bacterial adherence to cartilage were directly correlated with the presence of a functional cna gene. Greater than 70% of the mice injected with the Cna+ strains developed clinical signs of arthritis, whereas less than 27% of the animals injected with Cna- strains showed symptoms of disease. Furthermore, mice injected with the Cna+ strain Phillips had remarkably elevated levels of immunoglobulin G1 and interleukin-6 compared with mice injected with the Cna- mutant PH100. Taken together, these results demonstrate that collagen adhesin plays an important role in the pathogenesis of septic arthritis induced by S. aureus. Images PMID:8262622

  11. Preferential sites for intramolecular glucosepane cross-link formation in type I collagen: A thermodynamic study.

    PubMed

    Collier, Thomas A; Nash, Anthony; Birch, Helen L; de Leeuw, Nora H

    2015-10-01

    The extracellular matrix (ECM) undergoes progressive age-related stiffening and loss of proteolytic digestibility due to an increase in concentration of advanced glycation end products (AGEs). The most abundant AGE, glucosepane, accumulates in collagen with concentrations over 100 times greater than all other AGEs. Detrimental collagen stiffening properties are believed to play a significant role in several age-related diseases such as osteoporosis and cardiovascular disease. Currently little is known of the potential location of covalently cross-linked glucosepane formation within collagen molecules; neither are there reports on how the respective cross-link sites affect the physical and biochemical properties of collagen. Using fully atomistic molecular dynamics simulations (MD) we have identified six sites where the formation of a covalent intra-molecular glucosepane cross-link within a single collagen molecule in a fibrillar environment is energetically favourable. Identification of these favourable sites enables us to align collagen cross-linking with experimentally observed changes to the ECM. For example, formation of glucosepane was found to be energetically favourable within close proximity of the Matrix Metalloproteinase-1 (MMP1) binding site, which could potentially disrupt collagen degradation. PMID:26049074

  12. Preferential sites for intramolecular glucosepane cross-link formation in type I collagen: A thermodynamic study

    PubMed Central

    Collier, Thomas A.; Nash, Anthony; Birch, Helen L.; de Leeuw, Nora H.

    2015-01-01

    The extracellular matrix (ECM) undergoes progressive age-related stiffening and loss of proteolytic digestibility due to an increase in concentration of advanced glycation end products (AGEs). The most abundant AGE, glucosepane, accumulates in collagen with concentrations over 100 times greater than all other AGEs. Detrimental collagen stiffening properties are believed to play a significant role in several age-related diseases such as osteoporosis and cardiovascular disease. Currently little is known of the potential location of covalently cross-linked glucosepane formation within collagen molecules; neither are there reports on how the respective cross-link sites affect the physical and biochemical properties of collagen. Using fully atomistic molecular dynamics simulations (MD) we have identified six sites where the formation of a covalent intra-molecular glucosepane cross-link within a single collagen molecule in a fibrillar environment is energetically favourable. Identification of these favourable sites enables us to align collagen cross-linking with experimentally observed changes to the ECM. For example, formation of glucosepane was found to be energetically favourable within close proximity of the Matrix Metalloproteinase-1 (MMP1) binding site, which could potentially disrupt collagen degradation. PMID:26049074

  13. Increase in the relative level of type V collagen during development and ageing of the placenta.

    PubMed Central

    Iwahashi, M; Ooshima, A; Nakano, R

    1996-01-01

    AIM: To obtain some insight into the extracellular matrix in the placenta, changes in the composition of collagens during placental development were investigated. METHODS: Collagen was extracted from placentas (group 1, 25-30 weeks, n = 21; group 2, 31-36 weeks, n = 32; and group 3, 37-41 weeks of gestation, n = 40) and the relative concentrations of various collagens were evaluated by SDS-PAGE. RESULTS: The ratio of the intensity of the alpha 1 (III) band to that of alpha 1 (I) chain collagen in group 3 placentas were lower than those in group 1 placentas. In contrast, the ratio of the intensity of the alpha 1 (V) band to that of alpha 1 (I) chain collagen in group 3 placentas were higher than those in group 1 and group 2 placentas. CONCLUSIONS: These results suggest that type V collagen might play an important role in the function of the placenta and that an increased relative concentration of type V collagen might be closely associated with the development and ageing of the placenta. Images PMID:8944612

  14. Fibril-forming collagens in lamprey.

    PubMed

    Kelly, J; Tanaka, S; Hardt, T; Eikenberry, E F; Brodsky, B

    1988-01-15

    Five types of collagen with triple-helical regions approximately 300 nm in length were found in lamprey tissues which show characteristic D-periodic collagen fibrils. These collagens are members of the fibril forming family of this primitive vertebrate. Lamprey collagens were characterized with respect to solubility, mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, carboxylmethyl-cellulose chromatography, peptide digestion patterns, composition, susceptibility to vertebrate collagenase, thermal stability, and segment long spacing-banding pattern. Comparison with fibril-forming collagens in higher vertebrates (types I, II, III, V, and XI) identified three lamprey collagens as types II, V, and XI. Both lamprey dermis and major body wall collagens had properties similar to type I but not the typical heterotrimer composition. Dermis molecules had only alpha 1(I)-like chains, while body wall molecules had alpha 2(I)-like chains combined with chains resembling lamprey type II. Neither collagen exhibited the interchain disulfide linkages or solubility properties of type III. The conservation of fibril organization in type II/type XI tissues in contrast to the major developments in type I and type III tissues after the divergence of lamprey and higher vertebrates is consistent with these results. The presence of type II and type I-like molecules as major collagens and types V and XI as minor collagens in the lamprey, and the differential susceptibility of these molecules to vertebrate collagenase is analogous to the findings in higher vertebrates. PMID:3335531

  15. Collagen Mimetic Peptides: Progress Towards Functional Applications

    PubMed Central

    Yu, S. Michael; Li, Yang; Kim, Daniel

    2015-01-01

    Traditionally, collagen mimetic peptides (CMPs) have been used for elucidating the structure of the collagen triple helix and the factors responsible for its stabilization. The wealth of fundamental knowledge on collagen structure and cell-extracellular matrix (ECM) interactions accumulated over the past decades has led to a recent burst of research exploring the potential of CMPs to recreate the higher order assembly and biological function of natural collagens for biomedical applications. Although a large portion of such research is still at an early stage, the collagen triple helix has become a promising structural motif for engineering self-assembled, hierarchical constructs similar to natural tissue scaffolds which are expected to exhibit unique or enhanced biological activities. This paper reviews recent progress in the field of collagen mimetic peptides that bears both direct and indirect implications to engineering collagen-like materials for potential biomedical use. Various CMPs and collagen-like proteins that mimic either structural or functional characteristics of natural collagens are discussed with particular emphasis on providing helpful information to bioengineers and biomaterials scientists interested in collagen engineering. PMID:26316880

  16. War, Conflict and Play. Debating Play

    ERIC Educational Resources Information Center

    Hyder, Tina

    2004-01-01

    Young refugees from many parts of the world are increasingly present in UK early years settings. This book explores the crucial importance of play for young refugee children's development. It considers the implications of war and conflict on young children and notes how opportunities for play are denied. It provides a framework for early years…

  17. Playing the Play: What the Children Want

    ERIC Educational Resources Information Center

    Kraus, Jo Anne

    2006-01-01

    Playing the Play describes the experiences of a storyteller and teacher of literature who created a literature-based literacy program at Concourse House, a homeless shelter in Bronx, New York, for women and their young children. This program is based on the belief that pleasure is the primary reason children want to learn to read, and that where…

  18. Bibliography on Play Therapy and Children's Play.

    ERIC Educational Resources Information Center

    Rogers, Mary Brown; L'Abate, Luciano

    The references listed are: (1) journals, (2) dissertation abstracts, (3) books, (4) reports, and (5) monographs. The main subjects covered are: (1) children's play, (2) psychotherapy with disturbed children through the medium of play therapy, and (3) various aspects of child development, both normal and abnormal. The materials listed date from…

  19. The Uses of Play

    ERIC Educational Resources Information Center

    Cabaniss, Thomas

    2005-01-01

    Teaching artists have techniques for keeping play alive and vital in their work. But how do they think of play as TAs? In this article, the author examines the role of play in the work and life of teaching artists.

  20. Colorectal cancer desmoplastic reaction up-regulates collagen synthesis and restricts cancer cell invasion.

    PubMed

    Coulson-Thomas, Vivien J; Coulson-Thomas, Yvette M; Gesteira, Tarsis F; de Paula, Cláudia A A; Mader, Ana M; Waisberg, Jaques; Pinhal, Maria A; Friedl, Andreas; Toma, Leny; Nader, Helena B

    2011-11-01

    During cancer cell growth many tumors exhibit various grades of desmoplasia, unorganized production of fibrous or connective tissue, composed mainly of collagen fibers and myofibroblasts. The accumulation of an extracellular matrix (ECM) surrounding tumors directly affects cancer cell proliferation, migration and spread; therefore the study of desmoplasia is of vital importance. Stromal fibroblasts surrounding tumors are activated to myofibroblasts and become the primary producers of ECM during desmoplasia. The composition, density and organization of this ECM accumulation play a major role on the influence desmoplasia has upon tumor cells. In this study, we analyzed desmoplasia in vivo in human colorectal carcinoma tissue, detecting an up-regulation of collagen I, collagen IV and collagen V in human colorectal cancer desmoplastic reaction. These components were then analyzed in vitro co-cultivating colorectal cancer cells (Caco-2 and HCT116) and fibroblasts utilizing various co-culture techniques. Our findings demonstrate that direct cell-cell contact between fibroblasts and colorectal cancer cells evokes an increase in ECM density, composed of unorganized collagens (I, III, IV and V) and proteoglycans (biglycan, fibromodulin, perlecan and versican). The desmoplastic collagen fibers were thick, with an altered orientation, as well as deposited as bundles. This increased ECM density inhibited the migration and invasion of the colorectal tumor cells in both 2D and 3D co-culture systems. Therefore this study sheds light on a possible restricting role desmoplasia could play in colorectal cancer invasion. PMID:21987222

  1. Collagen fibrillogenesis: fibronectin, integrins, and minor collagens as organizers and nucleators

    PubMed Central

    Kadler, Karl E; Hill, Adele; Canty-Laird, Elizabeth G

    2008-01-01

    Collagens are triple helical proteins that occur in the extracellular matrix (ECM) and at the cell–ECM interface. There are more than 30 collagens and collagen-related proteins but the most abundant are collagens I and II that exist as D-periodic (where D = 67 nm) fibrils. The fibrils are of broad biomedical importance and have central roles in embryogenesis, arthritis, tissue repair, fibrosis, tumor invasion, and cardiovascular disease. Collagens I and II spontaneously form fibrils in vitro, which shows that collagen fibrillogenesis is a selfassembly process. However, the situation in vivo is not that simple; collagen I-containing fibrils do not form in the absence of fibronectin, fibronectin-binding and collagen-binding integrins, and collagen V. Likewise, the thin collagen II-containing fibrils in cartilage do not form in the absence of collagen XI. Thus, in vivo, cellular mechanisms are in place to control what is otherwise a protein self-assembly process. This review puts forward a working hypothesis for how fibronectin and integrins (the organizers) determine the site of fibril assembly, and collagens V and XI (the nucleators) initiate collagen fibrillogenesis. PMID:18640274

  2. Second harmonic generation imaging of the collagen in myocardium for atrial fibrillation diagnosis

    NASA Astrophysics Data System (ADS)

    Tsai, Ming-Rung; Chiou, Yu-We; Sun, Chi-Kuang

    2009-02-01

    Myocardial fibrosis, a common sequela of cardiac hypertrophy, has been shown to be associated with arrhythmias in experimental models. Some research has indicated that myocardial fibrosis plays an important role in predisposing patients to atrial fibrillation. Second harmonic generation (SHG) is an optically nonlinear coherent process to image the collagen network. In this presentation, we observe the SHG images of the collagen matrix in atrial myocardium and we analyzed of collagen fibers arrangement by using Fourier-transform analysis. Moreover, comparing the SHG images of the collagen fibers in atrial myocardium between normal sinus rhythm (NSR) and atrial fibrillation (AF), our result indicated that it is possible to realize the relation between myocardial fibrosis and AF.

  3. Collagen expression in fibroblasts with a novel LMNA mutation

    SciTech Connect

    Nguyen, Desiree; Leistritz, Dru F.; Turner, Lesley; MacGregor, David; Ohson, Kamal; Dancey, Paul; Martin, George M.; Oshima, Junko . E-mail: picard@u.washington.edu

    2007-01-19

    Laminopathies are a group of genetic disorders caused by LMNA mutations; they include muscular dystrophies, lipodystrophies, and progeroid syndromes. We identified a novel heterozygous LMNA mutation, L59R, in a patient with the general appearance of mandibuloacral dysplasia and progeroid features. Examination of the nuclei of dermal fibroblasts revealed the irregular morphology characteristic of LMNA mutant cells. The nuclear morphological abnormalities of LMNA mutant lymphoblastoid cell lines were less prominent compared to those of primary fibroblasts. Since it has been reported that progeroid features are associated with increased extracellular matrix in dermal tissues, we compared a subset of these components in fibroblast cultures from LMNA mutants with those of control fibroblasts. There was no evidence of intracellular accumulation or altered mobility of collagen chains, or altered conversion of procollagen to collagen, suggesting that skin fibroblast-mediated matrix production may not play a significant role in the pathogenesis of this particular laminopathy.

  4. Collagen Expression in Fibroblasts with a Novel LMNA Mutation

    PubMed Central

    Nguyen, Desiree; Leistritz, Dru F.; Turner, Lesley; MacGregor, David; Ohson, Kamal; Dancey, Paul; Martin, George M.; Oshima, Junko

    2007-01-01

    Laminopathies are a group of genetic disorders caused by LMNA mutations; they include muscular dystrophies, lipodystrophies and progeroid syndromes. We identified a novel heterozygous LMNA mutation, L59R, in a patient with the general appearance of mandibuloacral dysplasia and progeroid features. Examination of the nuclei of dermal fibroblasts revealed the irregular morphology characteristic of LMNA mutant cells. The nuclear morphological abnormalities of LMNA mutant lymphoblastoid cell lines were less prominent compared to those of primary fibroblasts. Since it has been reported that progeroid features are associated with increased extracellular matrix in dermal tissues, we compared a subset of these components in fibroblast cultures from LMNA mutants with those of control fibroblasts. There was no evidence of intracellular accumulation or altered mobility of collagen chains, or altered conversion of procollagen to collagen, suggesting that skin fibroblast-mediated matrix production may not play a significant role in the pathogenesis of this particular laminopathy. PMID:17150192

  5. Interleukin-1 inhibits the synthesis of collagen by fibroblasts.

    PubMed

    Bhatnagar, R; Penfornis, H; Mauviel, A; Loyau, G; Saklatvala, J; Pujol, J P

    1986-10-01

    Human dermal fibroblasts, exposed to human or porcine Interleukin-1, responded by an inhibition of collagen synthesis in a dose dependent manner. Incubation with Il-1 for more than 8 h was required to see an appreciable effect. The phenomenon was not dependent on the presence of serum in the culture medium. Since a stimulation of prostaglandin E2 secretion was also observed in presence of Il-1, we investigated the eventual role of arachidonic acid metabolites in the phenomenon. Inhibitors interfering with arachidonate metabolism, namely indomethacin, acetyl salicylic acid, BW 755 C and NDGA had no influence on the inhibition of collagen synthesis caused by Il-1. These data suggest that both cyclooxygenase and lipoxygenase derived metabolites of arachidonic acid are unlikely to play a role in the mechanism. PMID:3492206

  6. Collagen-Based Biomaterials for Wound Healing

    PubMed Central

    Chattopadhyay, Sayani; Raines, Ronald T.

    2014-01-01

    With its wide distribution in soft and hard connective tissues, collagen is the most abundant of animal proteins. In vitro, natural collagen can be formed into highly organized, three-dimensional scaffolds that are intrinsically biocompatible, biodegradable, non-toxic upon exogenous application, and endowed with high tensile strength. These attributes make collagen the material of choice for wound healing and tissue engineering applications. In this article, we review the structure and molecular interactions of collagen in vivo; the recent use of natural collagen in sponges, injectables, films and membranes, dressings, and skin grafts; and the on-going development of synthetic collagen mimetic peptides as pylons to anchor cytoactive agents in wound beds. PMID:24633807

  7. A mathematical model of collagen lattice contraction

    PubMed Central

    Dallon, J. C.; Evans, E. J.; Ehrlich, H. Paul

    2014-01-01

    Two mathematical models for fibroblast–collagen interaction are proposed which reproduce qualitative features of fibroblast-populated collagen lattice contraction. Both models are force based and model the cells as individual entities with discrete attachment sites; however, the collagen lattice is modelled differently in each model. In the collagen lattice model, the lattice is more interconnected and formed by triangulating nodes to form the fibrous structure. In the collagen fibre model, the nodes are not triangulated, are less interconnected, and the collagen fibres are modelled as a string of nodes. Both models suggest that the overall increase in stress of the lattice as it contracts is not the cause of the reduced rate of contraction, but that the reduced rate of contraction is due to inactivation of the fibroblasts. PMID:25142520

  8. Stress controls the mechanics of collagen networks

    PubMed Central

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M.; Fabry, Ben; Weitz, David A.; MacKintosh, Fred C.

    2015-01-01

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress–strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks. PMID:26195769

  9. Depth-Dependent Changes in Collagen Organization in the Human Peripapillary Sclera

    PubMed Central

    Pijanka, Jacek K.; Spang, Martin T.; Sorensen, Thomas; Liu, Jun; Nguyen, Thao D.; Quigley, Harry A.; Boote, Craig

    2015-01-01

    Purpose The collagen structure of the human peripapillary sclera plays a significant role in determining optic nerve head (ONH) biomechanics, and is therefore of interest in the study of glaucoma. The aim of the current work was to map the anisotropic collagen structure of the normal human peripapillary sclera as a function of tissue depth. Methods Wide-angle x-ray scattering was used to quantify collagen fibril orientation at 0.5mm intervals across six 150μm-thick serial sections through the peripapillary sclera of eight normal European-derived human eyes. Two structural parameters were measured: 1) the relative number of fibrils preferentially aligned at a given angle within the tissue plane, 2) the degree of collagen alignment (anisotropy). Results The inner-most one-third of the peripapillary scleral stroma (nearest to the choroid) was characterised by collagen fibrils either randomly arranged or preferentially aligned radially with respect to the ONH. In contrast, the outer two-thirds of the tissue was dominated by a circumferential arrangement of collagen encircling the ONH. In all tissue regions the degree of collagen anisotropy peaked in the mid-stroma and progressively decreased towards the tissue surfaces, with the largest depth variations occurring in the inferior-nasal quadrant, and the smallest occurring in the superior-nasal quadrant. Conclusions Significant, region-specific variations in collagen structure are present in the human peripapillary sclera as a function of depth. In normal eyes, the circumferential collagen fibril architecture is most prominent in the outer two-thirds of the stroma, possibly as a mechanical adaption to more effectively support the lamina cribrosa at the level of its insertion into the scleral canal wall. PMID:25714753

  10. Objective assessment of endogenous collagen in vivo during tissue repair by laser induced fluorescence.

    PubMed

    Prabhu, Vijendra; Rao, Satish B S; Fernandes, Edward Mark; Rao, Anuradha C K; Prasad, Keerthana; Mahato, Krishna K

    2014-01-01

    Collagen, a triple helical protein with the primary role of mechanical function, provides tensile strength to the skin, and plays a pivotal task in tissue repair. During tissue regeneration, collagen level increases gradually and therefore, monitoring of such changes in vivo by laser induced fluorescence was the main objective behind the present study. In order to accomplish this, 15 mm diameter excisional wounds were created on six to eight week old Swiss albino mice. The collagen deposition accelerated upon irradiation of single exposure of 2 J/cm2 He-Ne laser dose immediately after wounding was recorded by laser induced autofluorescence in vivo along with un-illuminated and un-wounded controls. Autofluorescence spectra were recorded for each animal of the experimental groups on 0, 5, 10, 30, 45 and 60 days post-wounding, by exciting the granulation tissue/skin with 325 nm He-Cd laser. The variations in the average collagen intensities from the granulation tissue/skin of mice were inspected as a function of age and gender. Further, the spectral findings of the collagen synthesis in wound granulation tissue/un-wounded skin tissues were validated by Picro-Sirius red- polarized light microscopy in a blinded manner through image analysis of the respective collagen birefringence. The in vivo autofluorescence studies have shown a significant increase in collagen synthesis in laser treated animals as compared to the un-illuminated controls. Image analysis of the collagen birefringence further authenticated the ability of autofluorescence in the objective monitoring of collagen in vivo. Our results clearly demonstrate the potential of laser induced autofluorescence in the monitoring of collegen synthesis during tissue regeneration, which may have clinical implications. PMID:24874229

  11. Laminin peptide YIGSR induces collagen synthesis in Hs27 human dermal fibroblasts

    SciTech Connect

    Yoon, Jong Hyuk; Kim, Jaeyoon; Lee, Hyeongjoo; Kim, So Young; Jang, Hwan-Hee; Ryu, Sung Ho; Kim, Beom Joon; Lee, Taehoon G.

    2012-11-23

    Highlights: Black-Right-Pointing-Pointer We identify a function of the YIGSR peptide to enhance collagen synthesis in Hs27. Black-Right-Pointing-Pointer YIGSR peptide enhanced collagen type 1 synthesis both of gene and protein levels. Black-Right-Pointing-Pointer There were no changes in cell proliferation and MMP-1 level in YIGSR treatment. Black-Right-Pointing-Pointer The YIGSR effect on collagen synthesis mediated activation of FAK, pyk2 and ERK. Black-Right-Pointing-Pointer The YIGSR-induced FAK and ERK activation was modulated by FAK and MEK inhibitors. -- Abstract: The dermal ECM is synthesized from fibroblasts and is primarily compromised of fibrillar collagen and elastic fibers, which support the mechanical strength and resiliency of skin, respectively. Laminin, a major glycoprotein located in the basement membrane, promotes cell adhesion, cell growth, differentiation, and migration. The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of the {beta}1 chain, is known to be a functional motif with effects on the inhibition of tumor metastasis, the regulation of sensory axonal response and the inhibition of angiogenesis through high affinity to the 67 kDa laminin receptor. In this study, we identified a novel function of the YIGSR peptide to enhance collagen synthesis in human dermal fibroblasts. To elucidate this novel function regarding collagen synthesis, we treated human dermal fibroblasts with YIGSR peptide in both a time- and dose-dependent manner. According to subsequent experiments, we found that the YIGSR peptide strongly enhanced collagen type 1 synthesis without changing cell proliferation or cellular MMP-1 level. This YIGSR peptide-mediated collagen type 1 synthesis was modulated by FAK inhibitor and MEK inhibitor. This study clearly reveals that YIGSR peptide plays a novel function on the collagen type 1 synthesis of dermal fibroblasts and also suggests that YIGSR is a strong candidate

  12. The Play of Psychotherapy

    ERIC Educational Resources Information Center

    Marks-Tarlow, Terry

    2012-01-01

    The author reviews the role of play within psychotherapy. She does not discuss the formal play therapy especially popular for young children, nor play from the Jungian perspective that encourages the use of the sand tray with adults. Instead, she focuses on the informal use of play during psychotherapy as it is orchestrated intuitively. Because…

  13. Two people playing together: some thoughts on play, playing, and playfulness in psychoanalytic work.

    PubMed

    Vliegen, Nicole

    2009-01-01

    Children's play and the playfulness of adolescents and adults are important indicators of personal growth and development. When a child is not able to play, or an adolescent/adult is not able to be playful with thoughts and ideas, psychotherapy can help to find a more playful and creative stance. Elaborating Winnicott's (1968, p. 591) statement that "psychotherapy has to do with two people playing together," three perspectives on play in psychotherapy are discussed. In the first point of view, the child gets in touch with and can work through aspects of his or her inner world, while playing in the presence of the therapist. The power of play is then rooted in the playful communication with the self In a second perspective, in play the child is communicating aspects of his or her inner world to the therapist as a significant other. In a third view, in "playing together" child and therapist are coconstructing new meanings. These three perspectives on play are valid at different moments of a therapy process or for different children, depending on the complex vicissitudes of the child's constitution, life experiences, development, and psychic structure. Concerning these three perspectives, a parallel can be drawn between the therapist's attitude toward the child's play and the way the therapist responds to the verbal play of an adolescent or adult. We illustrate this with the case of Jacob, a late adolescent hardly able to play with ideas. PMID:20578437

  14. Magnetic Resonance Microscopy of Collagen Mineralization

    PubMed Central

    Chesnick, Ingrid E.; Mason, Jeffrey T.; Giuseppetti, Anthony A.; Eidelman, Naomi; Potter, Kimberlee

    2008-01-01

    A model mineralizing system was subjected to magnetic resonance microscopy to investigate how water proton transverse (T2) relaxation times and magnetization transfer ratios can be applied to monitor collagen mineralization. In our model system, a collagen sponge was mineralized with polymer-stabilized amorphous calcium carbonate. The lower hydration and water proton T2 values of collagen sponges during the initial mineralization phase were attributed to the replacement of the water within the collagen fibrils by amorphous calcium carbonate. The significant reduction in T2 values by day 6 (p < 0.001) was attributed to the appearance of mineral crystallites, which were also detected by x-ray diffraction and scanning electron microscopy. In the second phase, between days 6 and 13, magnetic resonance microscopy properties appear to plateau as amorphous calcium carbonate droplets began to coalesce within the intrafibrillar space of collagen. In the third phase, after day 15, the amorphous mineral phase crystallized, resulting in a reduction in the absolute intensity of the collagen diffraction pattern. We speculate that magnetization transfer ratio values for collagen sponges, with similar collagen contents, increased from 0.25 ± 0.02 for control strips to a maximum value of 0.31 ± 0.04 at day 15 (p = 0.03) because mineral crystals greatly reduce the mobility of the collagen fibrils. PMID:18487295

  15. Ionic solutes impact collagen scaffold bioactivity.

    PubMed

    Pawelec, K M; Husmann, A; Wardale, R J; Best, S M; Cameron, R E

    2015-02-01

    The structure of ice-templated collagen scaffolds is sensitive to many factors. By adding 0.5 wt% of sodium chloride or sucrose to collagen slurries, scaffold structure could be tuned through changes in ice growth kinetics and interactions of the solute and collagen. With ionic solutes (sodium chloride) the entanglements of the collagen molecule decreased, leading to fibrous scaffolds with increased pore size and decreased attachment of chondrocytes. With non-ionic solutes (sucrose) ice growth was slowed, leading to significantly reduced pore size and up-regulated cell attachment. This highlights the large changes in structure and biological function stimulated by solutes in ice-templating systems. PMID:25649518

  16. Child's Play: Therapist's Narrative

    PubMed Central

    Reddy, Rajakumari P.; Hirisave, Uma

    2014-01-01

    Play has been recognized as an essential component to children's healthy development. Schools of play therapy differ philosophically and technically, but they all embrace the therapeutic and developmental properties of play. This case report is an illustration of how a 6-year-old child with emotional disorder was facilitated to express concerns in child-centered play therapy. The paper discusses the therapist's narration of the child's play. PMID:24860228

  17. Collagen XII: Protecting bone and muscle integrity by organizing collagen fibrils.

    PubMed

    Chiquet, Matthias; Birk, David E; Bönnemann, Carsten G; Koch, Manuel

    2014-08-01

    Collagen XII, largest member of the fibril-associated collagens with interrupted triple helix (FACIT) family, assembles from three identical α-chains encoded by the COL12A1 gene. The molecule consists of three threadlike N-terminal noncollagenous NC3 domains, joined by disulfide bonds and a short interrupted collagen triple helix toward the C-terminus. Splice variants differ considerably in size and properties: "small" collagen XIIB (220 kDa subunit) is similar to collagen XIV, whereas collagen XIIA (350 kDa) has a much larger NC3 domain carrying glycosaminoglycan chains. Collagen XII binds to collagen I-containing fibrils via its collagenous domain, whereas its large noncollagenous arms interact with other matrix proteins such as tenascin-X. In dense connective tissues and bone, collagen XII is thought to regulate organization and mechanical properties of collagen fibril bundles. Accordingly, recent findings show that collagen XII mutations cause Ehlers-Danlos/myopathy overlap syndrome associated with skeletal abnormalities and muscle weakness in mice and humans. PMID:24801612

  18. Molecules in Focus: Collagen XII: Protecting bone and muscle integrity by organizing collagen fibrils

    PubMed Central

    Chiquet, Matthias; Birk, David E.; Bönnemann, Carsten G.; Koch, Manuel

    2014-01-01

    Collagen XII, largest member of the fibril-associated collagens with interrupted triple helix (FACIT) family, assembles from three identical α-chains encoded by the COL12A1 gene. The molecule consists of three threadlike N-terminal noncollagenous NC3 domains, joined by disulfide bonds and a short interrupted collagen triple helix towards the C-terminus. Splice variants differ considerably in size and properties: "small" collagen XIIB (220 kDa subunit) is similar to collagen XIV, whereas collagen XIIA (350 kDa) has a much larger NC3 domain carrying glycosaminoglycan chains. Collagen XII binds to collagen I-containing fibrils via its collagenous domain, whereas its large noncollagenous arms interact with other matrix proteins such as tenascin-X. In dense connective tissues and bone, collagen XII is thought to regulate organization and mechanical properties of collagen fibril bundles. Accordingly, recent findings show that collagen XII mutations cause Ehlers-Danlos/myopathy overlap syndrome associated with skeletal abnormalities and muscle weakness in mice and humans. PMID:24801612

  19. Play: early and eternal.

    PubMed Central

    Mears, C E; Harlow, H F

    1975-01-01

    A systematic 12-week investigation of development of play behavior was conducted with eight socially reared rhesus monkey infants. A new, basic and primary play form termed self-motion play or peragration was identified and examined. This behavior follows a human model which includes a wide range of pleasurable activities involving motion of the body through space, e.g., rocking, swinging, running, leaping, and water or snow skiing. It can be argued that self-motion play is the initial primate play form and because of its persistence constitutes a reinforcing agent for maintaining many complex patterns and even pastimes. Monkey self-motion play in the present study was divided into five separate patterns in order to compare the relative importance of social and individual peragration play, the role of apparatus and the overall developmental relationships between the different individual and social self-motion play patterns. The data showed that from 90 to 180 days of age self-motion play was independent of other forms of play, that individual self-motion play appeared earlier and with significantly greater increases in frequency than did social self-motion play, and that apparatus was a necessary component for significant increases in social self-motion play. Other findings were that self-motion play existed independent of locomotion and, though initiated by exploration, was separate from it. Therapeutic implications of self-motion play were discussed. Images PMID:1057178

  20. PREFACE: MCWASP XIII: International Conference on Modeling of Casting, Welding and Advanced Solidification Processes

    NASA Astrophysics Data System (ADS)

    Ludwig, Andreas

    2012-07-01

    Due to fast-paced development in computer technologies during the last three decades, computer-based process modeling has become an important tool for the improvement of existing process technologies and the development of new, innovative technologies. With the help of numerical process simulations, complex and costly experimental trials can now be reduced to a minimum. For metallurgical processes in particular, computer simulations are of outstanding importance, as the flow and solidification of molten alloys or the formation of microstructure and defects can hardly be observed experimentally. Corresponding computer simulations allow us inside views into the key process phenomena and so offer great potential for optimization. In 1980 the conference series 'Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP)' was started up, and has now been continued by holding the 13th international conference on 'Modeling of Casting, Welding and Advanced Solidification Processes', MCWASP XIII, in Schladming, Austria, from June 17-22 2012. Around 200 scientists from industry and academia, coming from 20 countries around the globe attended 78 oral and 50 poster presentations on different aspects of solidification-related modeling topics. Besides process-related sessions such as (i) Ingot and Shape Casting, (ii) Continuous Casting and Direct Chill Casting, (iii) Directional Solidification and Zone Melting, (iv) Welding, and (v) Centrifugal Casting, a larger focus was put on (vi) Experimental Investigation and In-Situ Observations. In recent years, this topic has been significantly strengthened as advanced synchrotron technologies allow fantastic in-situ observations of phenomena happening inside small metallic samples. These observations will definitely serve as a benchmark for the modeling community. Further macroscopic aspects of advanced solidification science were tackled in the sessions (vii) Electromagnetic Coupling, (viii) Thermomechanics, (ix

  1. PBT assessment using the revised annex XIII of REACH: a comparison with other regulatory frameworks.

    PubMed

    Moermond, Caroline T A; Janssen, Martien P M; de Knecht, Joop A; Montforts, Mark H M M; Peijnenburg, Willie J G M; Zweers, Patrick G P C; Sijm, Dick T H M

    2012-04-01

    There is no uniform Persistent, Bioaccumulative, Toxic (PBT) or very Persistent, very Bioaccumulative (vPvB) assessment of chemicals in Europe, as the various regulatory frameworks use only limited or dissimilar PBT assessments, or none at all. The European REACH Regulation requires a PBT/vPvB assessment for all chemical substances that are produced within or imported into the EU in amounts exceeding 10 tonnes per year, using the criteria as described in REACH Annex XIII. However, not all substances on the EU market need to be screened according to these criteria under REACH. For a number of substances, such as those imported or produced in lower volumes, there is no REACH requirement, and for human and veterinary medicinal products, biocides, plant protection products, and food and feed additives, other EU legislation is in force to regulate their marketing and use. Compounds may also be screened for PBT properties within international agreements, such as the Oslo Paris Convention (OSPAR), the IMO Ballast Water Management Convention, the UNECE POP Protocol, and the UNEP Stockholm Convention on Persistent Organic Pollutants (POPs), which all have their own set of PBT or POP criteria. This study compares the PBT/vPvB assessment under REACH with PBT or POP assessments performed within other regulatory frameworks. Attention is paid to the process of PBT/vPvB/POP identification and which legislative steps can be taken if the PBT/vPvB/POP status is assigned. In addition to the different PBT or POP criteria of the various frameworks, descriptions of these criteria and approaches for application of weight of evidence also vary. Some EU frameworks still refer to the criteria in the former Technical Guidance Documents (TGD) of 2003, which preceded REACH. Although differences between the old TGD criteria and those in the REACH Annex XIII are small, this does cause dissimilarities among the frameworks. The risk management follow-up of a PBT or vPvB identification, which may

  2. Novel aspects of blood coagulation factor XIII. I. Structure, distribution, activation, and function

    SciTech Connect

    Muszbek, L.; Adany, R.; Mikkola, H.

    1996-10-01

    Blood coagulation factor XIII (FXIII) is a protransglutaminase that becomes activated by the concerted action of thrombin and Ca{sup 2+} in the final stage of the clotting cascade. In addition to plasma, FXIII also occurs in platelets, monocytes, and monocyte-derived macrophages. While the plasma factor is a heterotetramer consisting of paired A and B subunits (A{sub 2}B{sub 2}), its cellular counterpart lacks the B subunits and is a homodimer of potentially active A subunits (A{sub 2}). The gene coding for the A and B subunits has been localized to chromosomes 6p24-25 and 1q31-32.1, respectively. The genomic as well as the primary protein structure of both subunits has been established. Plasma FXIII circulates in association with its substrate precursor, fibrinogen. Fibrin(ogen) has an important regulatory role in the activation of plasma FXIII, for instance the proteolytic removal of activation peptide by thrombin, the dissociation of subunits A and B, and the exposure of the originally buried active site on the free A subunits. The end result of this process is the formation of an active transglutaminase, which crosslinks peptide chains through {epsilon}({gamma}-glutamyl)lysyl isopeptide bonds. The protein substrates of activated FXIII include components of the clotting-fibrinolytic system, adhesive and contractile proteins. The main physiological function of plasma FXIII is to cross-link fibrin and protect it from the fibrinolytic enzyme plasmin. The latter effect is achieved mainly by covalently linking {alpha}{sub 2} antiplasmin, the most potent physiological inhibitor of plasmin, to fibrin. Plasma FXIII seems to be involved in wound healing and tissue repair, and it is essential to maintaining pregnancy. Cellular FXIII, if exposed to the surface of the cells, might support or perhaps take over the hemostatic functions of plasma FXIII; however, its intracellular role has remained mostly unexplored. 328 refs., 4 figs.

  3. Nucleotide sequence of the gene for the b subunit of human factor XIII

    SciTech Connect

    Bottenus, R.E.; Ichinose, A.; Davie, E.W. )

    1990-12-01

    Factor XIII (M{sub r} 320 000) is a blood coagulation factor that stabilizes and strengthens the fibrin clot. It circulates in blood as a tetramer composed of two a subunits (M{sub r} 75 000 each) and two b subunits (M{sub r} 80 000 each). The b subunit consists of 641 amino acids and includes 10 tandem repeats of 60 amino acids known as GP-I structures, short consensus repeats (SCR), or sushi domains. In the present study, the human gene for the b subunit has been isolated from three different genomic libraries prepared in {lambda} phage. Fifteen independent phage with inserts coding for the entire gene were isolated and characterized by restriction mapping, Southern blotting, and DNA sequencing. The gene was found to be 28 kilobases in length and consisted of 12 exons (I-XII) separated by 11 intervening sequences. The leader sequence was encoded by exon I, while the carbonyl-terminal region of the protein was encoded by exon XII. Exons II-XI each coded for a single sushi domain, suggesting that the gene evolved through exon shuffling and duplication. The 12 exons in the gene ranged in size from 64 to 222 base pairs, while the introns ranged in size from 87 to 9970 nucleotides and made up 92{percent} of the gene. One nucleotide change was found in the coding region of the gene when its sequence was compared to that of the cDNA. This difference, however, did not result in a change in the amino acid sequence of the protein.

  4. Factor XIII-A subunit Val34Leu polymorphism in fatal atherothrombotic ischemic stroke.

    PubMed

    Shemirani, Amir-Houshang; Antalfi, Bálint; Pongrácz, Endre; Mezei, Zoltán András; Bereczky, Zsuzsanna; Csiki, Zoltán

    2014-06-01

    Factor XIII (FXIII) is a regulator of fibrinolysis and clot firmness. Val34Leu polymorphism of its potentially active A subunit (FXIII-A) leads to faster activation of FXIII, influences clot structure and provides a moderate protection against coronary artery disease. The effect of FXIII-A Val34Leu polymorphism on the risk of atherothrombotic ischemic stroke (AIS) has been investigated in a few studies with contradictory results. In all previous studies, only patients surviving AIS were enrolled and sex-specific effects were not explored. In this retrospective multicenter cohort, we investigated the effect of FXIII-A Val34Leu polymorphism on the risk of fatal AIS in women and men. DNA isolation and genetic determinations in the case of 316 patients who died of AIS were carried out on paraffin-embedded tissue specimens. Genetic analyses for population controls, patients with history of AIS and sex-matched controls were performed on extracted genomic DNA from peripheral blood leukocytes. The prevalence of homozygous wild-type, and heterozygous genotypes, Leu34 carriers and Leu34 allele was not different significantly between the patients with fatal AIS and their respective controls. Logistic regression analysis with age as co-variant demonstrated that in women, homozygous presentation of Leu34 allele represented a more than three-fold increased risk of AIS with fatal outcome. The results demonstrate that FXIII-A Val34Leu polymorphism does not influence the occurrence of AIS, but has an effect on the severity of its outcome. This effect is sex-specific and in homozygous women, the prothrombotic/antifibrinolytic effects of FXIII-A Val34Leu polymorphism seem to prevail. PMID:24686102

  5. Factor XIII Val34Leu polymorphism and recurrent myocardial infarction in patients with coronary artery disease.

    PubMed

    Kreutz, Rolf P; Bitar, Abbas; Owens, Janelle; Desta, Zeruesenay; Breall, Jeffrey A; von der Lohe, Elisabeth; Sinha, Anjan; Vatta, Matteo; Nystrom, Perry; Jin, Yan; Flockhart, David A

    2014-10-01

    Factor XIII (FXIII) is necessary for cross linking of fibrin strands and generation of stable fibrin clot. FXIII Val34Leu is a common genetic single nucleotide polymorphism that has been associated with accelerated fibrin stabilization and reduced rate of fibrinolysis. The contribution of Val34Leu to long term risk of recurrent myocardial infarction (MI) in patients with coronary stenting has not been conclusively established. The objective of the study was to examine the effects of Val34Leu on fibrin generation, platelet aggregation, and long term clinical outcomes in patients with coronary artery disease treated with dual antiplatelet therapy. Patients with angiographically documented coronary artery disease who were treated with aspirin and clopidogrel were enrolled (n = 211). Light transmittance aggregometry and plasma fibrin clot formation using thrombelastography (TEG) were determined. Genotyping of Val34Leu was performed using Taqman assay. Clinical events during follow up were recorded. Homozygous carriers of 34 Leu variant had significantly shorter fibrin clot formation time as compared to wild type individuals (TEG K: 1.27 ± 0.3 vs. 1.68 ± 1.1 min, p = 0.011). The Val34Leu variant was associated with gene dose dependent increased risk of MI (log rank, p = 0.002) or occurrence of composite of MI and CV death (log rank, p = 0.005) with highest event rates observed in homozygous carriers of 34 Leu. In summary, FXIII Val34Leu polymorphism was associated with increased rate of fibrin stabilization in homozygous carriers of the variant and may increase risk of recurrent MI and death in patients with angiographically established coronary artery disease treated with dual antiplatelet therapy. PMID:24510702

  6. Nanolayered Features of Collagen-like Peptides

    NASA Technical Reports Server (NTRS)

    Valluzzi, Regina; Bini, Elisabetta; Haas, Terry; Cebe, Peggy; Kaplan, David L.

    2003-01-01

    We have been investigating collagen-like model oligopeptides as molecular bases for complex ordered biomimetic materials. The collagen-like molecules incorporate aspects of native collagen sequence and secondary structure. Designed modifications to native primary and secondary structure have been incorporated to control the nanostructure and microstructure of the collagen-like materials produced. We find that the collagen-like molecules form a number of lyotropic rod liquid crystalline phases, which because of their strong temperature dependence in the liquid state can also be viewed as solvent intercalated thermotropic liquid crystals. The liquid crystalline phases formed by the molecules can be captured in the solid state by drying off solvent, resulting in solid nanopatterned (chemically and physically) thermally stable (to greater than 100 C) materials. Designed sequences which stabilize smectic phases have allowed a variety of nanoscale multilayered biopolymeric materials to be developed. Preliminary investigations suggest that chemical patterns running perpendicular to the smectic layer plane can be functionalized and used to localize a variety of organic, inorganic, and organometallic moieties in very simple multilayered nanocomposites. The phase behavior of collagen-like oligopeptide materials is described, emphasizing the correlation between mesophase, molecular orientation, and chemical patterning at the microscale and nanoscale. In many cases, the textures observed for smectic and hexatic phase collagens are remarkably similar to the complex (and not fully understood) helicoids observed in biological collagen-based tissues. Comparisons between biological morphologies and collagen model liquid crystalline (and solidified materials) textures may help us understand the molecular features which impart order and function to the extracellular matrix and to collagen-based mineralized tissues. Initial studies have utilized synthetic collagen-like peptides while

  7. Collagen structure: new tricks from a very old dog.

    PubMed

    Bella, Jordi

    2016-04-15

    The main features of the triple helical structure of collagen were deduced in the mid-1950s from fibre X-ray diffraction of tendons. Yet, the resulting models only could offer an average description of the molecular conformation. A critical advance came about 20 years later with the chemical synthesis of sufficiently long and homogeneous peptides with collagen-like sequences. The availability of these collagen model peptides resulted in a large number of biochemical, crystallographic and NMR studies that have revolutionized our understanding of collagen structure. High-resolution crystal structures from collagen model peptides have provided a wealth of data on collagen conformational variability, interaction with water, collagen stability or the effects of interruptions. Furthermore, a large increase in the number of structures of collagen model peptides in complex with domains from receptors or collagen-binding proteins has shed light on the mechanisms of collagen recognition. In recent years, collagen biochemistry has escaped the boundaries of natural collagen sequences. Detailed knowledge of collagen structure has opened the field for protein engineers who have used chemical biology approaches to produce hyperstable collagens with unnatural residues, rationally designed collagen heterotrimers, self-assembling collagen peptides, etc. This review summarizes our current understanding of the structure of the collagen triple helical domain (COL×3) and gives an overview of some of the new developments in collagen molecular engineering aiming to produce novel collagen-based materials with superior properties. PMID:27060106

  8. Laser welding and collagen crosslinks

    SciTech Connect

    Reiser, K.M.; Last, J.A.; Small, W. IV; Maitland, D.J.; Heredia, N.J.; Da Silva, L.B.; Matthews, D.L.

    1997-02-20

    Strength and stability of laser-welded tissue may be influenced, in part, by effects of laser exposure on collagen crosslinking. We therefore studied effects of diode laser exposure (805 nm, 1-8 watts, 30 seconds) + indocyanine green dye (ICG) on calf tail tendon collagen crosslinks. Effect of ICG dye alone on crosslink content prior to laser exposure was investigated; unexpectedly, we found that ICG-treated tissue had significantly increased DHLNL and OHP, but not HLNL. Laser exposure after ICG application reduced elevated DHLNL and OHP crosslink content down to their native levels. The monohydroxylated crosslink HLNL was inversely correlated with laser output (p<0.01 by linear regression analysis). DHLNL content was highly correlated with content of its maturational product, OHP, suggesting that precursor-product relations are maintained. We conclude that: (1)ICG alone induces DHLNL and OHP crosslink formation; (2)subsequent laser exposure reduces the ICG-induced crosslinks down to native levels; (3)excessive diode laser exposure destroys normally occurring HLNL crosslinks.

  9. Genetics Home Reference: collagen VI-related myopathy

    MedlinePlus

    ... Genetics Home Health Conditions collagen VI-related myopathy collagen VI-related myopathy Enable Javascript to view the ... boxes. Download PDF Open All Close All Description Collagen VI-related myopathy is a group of disorders ...

  10. Cartilage collagen analysis in the chondrodystrophies.

    PubMed

    Horton, W A; Chou, J W; Machado, M A

    1985-09-01

    A simple and reproducible method for analyzing small samples of cartilage collagens was developed. Following extraction with guanidine HCl, the cartilage specimens were digested directly with CNBr and the resultant peptides separated by gel-permeation high-performance liquid chromatography. Resting cartilage collagen CNBr peptide maps differed from normal in two inherited chondrodystrophies, achondrogenesis II and spondyloepiphyseal dysplasia congenita. PMID:4053564

  11. Pseudomembranous collagenous colitis with superimposed drug damage.

    PubMed

    Villanacci, Vincenzo; Cristina, Silvia; Muscarà, Maurizio; Saettone, Silvia; Broglia, Laura; Antonelli, Elisabetta; Salemme, Marianna; Occhipinti, Pietro; Bassotti, Gabrio

    2013-11-01

    Pseudomembranous collagenous colitis is a rare pathological condition, not related to infectious agents, and characterized by thickening of the subepithelial collagen and formation of pseudomembranes. We report one such case, which responded to budesonide treatment after failures of previous approaches given, being unaware of the correct diagnosis. PMID:24080283

  12. Learning through Role Play.

    ERIC Educational Resources Information Center

    Simmons, Sandra

    2001-01-01

    Explains how role playing can provide enriching experiences that develop children's literacy and numeracy skills. Lists key ingredients of good role playing and suggests ways to plan them and prepare space for them. (SK)

  13. Adlerian Play Therapy.

    ERIC Educational Resources Information Center

    Kottman, Terry; Warlick, Jayne

    1990-01-01

    Describes Adlerian method of play therapy. Claims Adlerian therapy represents an integration of the concepts and techniques of individual psychology into a method of using play to help troubled children. (Author/ABL)

  14. Role-Playing Mitosis.

    ERIC Educational Resources Information Center

    Wyn, Mark A.; Stegink, Steven J.

    2000-01-01

    Introduces a role playing activity that actively engages students in the learning process of mitosis. Students play either chromosomes carrying information, or cells in the cell membrane. (Contains 11 references.) (Author/YDS)

  15. A novel benign solution for collagen processing

    NASA Astrophysics Data System (ADS)

    Arnoult, Olivier

    Collagen is the main protein constituting the extracellular matrix (ECM) of tissues in the body (skin, cartilage, blood vessels...). It exists many types of collagen, this work studies only fibrillar collagen (e.g. collagen type I contained in the skin) that exhibits a triple helical structure composed of 3 alpha-helical collagen chains. This particular and defined hierarchical structure is essential to the biological and mechanical properties of the collagen. Processing collagen into scaffolds to mimic the ECM is crucial for successful tissue engineering. Recently collagen was processed into fibrous and porous scaffold using electrospinning process. However the solvent (HFIP) used for electrospinning is extremely toxic for the user and expensive. This work shows that HFIP can be replaced by a benign mixture composed of water, salt and alcohol. Yet only three alcohols (methanol, ethanol and iso-propanol) enable the dissolution of large quantity of collagen in the benign mixture, with a wide range of alcohol to buffer ratio, and conserve the collagen hierarchical structure at least as well as the HFIP. Collagen can be electrospun from the benign mixture into sub-micron fibers with concentrations as low as 6 wt-% for a wide range of alcohol to buffer ratio, with at least 10wt-% of salt, and any of the three alcohols. Specific conditions yield nano size fibers. After processing from HFIP or a benign mixture, collagen is water soluble and needs to be chemically crosslink for tissue engineering application. Post-crosslinking with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) results in the loss of the scaffold fibrous aspect and porosity, hence it is useless for tissue engineering. Such issue could be prevented by incorporating the crosslinker into the mixture prior to electrospinning. When EDC is used alone, collagen forms a gel in the mixture within minutes, preventing electrospinning. The addition of N-hydroxysuccinimide (NHS) in excess to EDC

  16. Photoinduced effect of hypericin on collagen and tissues with high collagen content

    NASA Astrophysics Data System (ADS)

    Yova, Dido M.; Theodossiou, Theodossis; Hovhannisyan, Vladimir A.

    1999-01-01

    The photoinduced effects of hypericin, a polycyclic quinone, on collagen has been investigated. It was found that after laser irradiation at both 532 nm and 337 nm, the spectral form of triple helix structure collagen fluorescence, changed to a spectral profile bearing resemblance to that of its polypeptide single chain counterpart, gelatin, or heated collagen. The effect of Chlorin e6 on collagen was also investigated and proved to be dissimilar to that of hypericin and not indicative of profound structural alterations. Second Harmonic Generation (SHG) of 1064 nm- nanosecond laser radiation in collagen was studied. While it was very efficient for pure collagen, the signal intensity was found to diminish by at least an order of magnitude after hypericin photosensitization or heating. The above noted fluorescence spectra form alteration was also observed in a smaller scale in collagen rich chicken tissue (tendon). Non sensitized chicken tendon tissue exhibited very efficient SHG, unlike skin and artery samples.

  17. Proline puckering parameters for collagen structure simulations

    SciTech Connect

    Wu, Di

    2015-03-15

    Collagen is made of triple helices rich in proline residues, and hence is influenced by the conformational motions of prolines. Because the backbone motions of prolines are restricted by the helical structures, the only side chain motion—proline puckering—becomes an influential factor that may affect the stability of collagen structures. In molecular simulations, a proper proline puckering population is desired so to yield valid results of the collagen properties. Here we design the proline puckering parameters in order to yield suitable proline puckering populations as demonstrated in the experimental results. We test these parameters in collagen and the proline dipeptide simulations. Compared with the results of the PDB and the quantum calculations, we propose the proline puckering parameters for the selected collagen model simulations.

  18. Bioengineered collagens: emerging directions for biomedical materials.

    PubMed

    Ramshaw, John A M; Werkmeister, Jerome A; Dumsday, Geoff J

    2014-01-01

    Mammalian collagen has been widely used as a biomedical material. Nevertheless, there are still concerns about the variability between preparations, particularly with the possibility that the products may transmit animal-based diseases. Many groups have examined the possible application of bioengineered mammalian collagens. However, translating laboratory studies into large-scale manufacturing has often proved difficult, although certain yeast and plant systems seem effective. Production of full-length mammalian collagens, with the required secondary modification to give proline hydroxylation, has proved difficult in E. coli. However, recently, a new group of collagens, which have the characteristic triple helical structure of collagen, has been identified in bacteria. These proteins are stable without the need for hydroxyproline and are able to be produced and purified from E. coli in high yield. Initial studies indicate that they would be suitable for biomedical applications. PMID:24717980

  19. Play, Policy & Practice.

    ERIC Educational Resources Information Center

    Klugman, Edgar, Ed.

    In 1992, the U.S.-Israel Binational Science Foundation (BSF), in conjunction with Wheelock College (Boston), sponsored its second workshop on children's play, entitled "Play and Cognitive Ability: The Cultural Context." This volume reflects the presentations and discussions held at the workshop, offering perspectives on children's play that, taken…

  20. The Pedagogy of Play

    ERIC Educational Resources Information Center

    Giesbrecht, Sheila

    2012-01-01

    Play is important. Environmental educators Sobel and Louv write about the relationship between children and outside play and suggest that early transcendental experiences within nature allow children to develop empathetic orientations towards the natural world. Children who play out-of-doors develop an appreciation for the environment and…

  1. Play Is the Way

    ERIC Educational Resources Information Center

    Gross, Steve; Sanderson, Rebecca Cornelli

    2012-01-01

    Historically, play has been viewed as a frivolous break from important endeavors like working and learning when, in fact, a child's ability to fully and freely engage in play is essential to their learning, productivity, and overall development. A natural drive to play is universal across all young mammals. Children from every society on earth…

  2. Changes in corneal collagen induced by holmium:YAG laser irradiation

    NASA Astrophysics Data System (ADS)

    Timberlake, George T.; Reinke, Martin H.; Miller, Alvin

    1996-05-01

    Holmium:YAG laser thermokeratoplasty corrects hyperopia (farsightedness) by producing small areas of corneal collagen shrinkage that cause the central cornea to bulge outward, increasing optical power. Collagen shrinkage is probably caused by laser-heated corneal water, but details of the shrinkage mechanism are not known. We investigated the shrinkage mechanism by measuring changes in corneal ultrastructure, surface shrinkage, water content, and strength following Ho:YAG laser exposures. Morphological changes in collagen were documented by measurements from electron micrographs. Corneal adhesive strength was determined by measuring tearing force in a plane parallel to the corneal surface. Laser-induced water loss was measured by weighing corneal samples before and after exposure. Corneal surface shrinkage was assessed by photographing the movement of particles on the cornea. Lasered collagen fibrils increased in diameter, lost their orderly arrangement, and appeared `frayed.' The corneal surface contracted toward lasered areas with a maximal shift of approximately 190 micrometers , more than could be explained by a model based on collagen fibril changes. Water loss plays a minor role in corneal shrinkage since corneal samples lost about only about 1.4% of their weight after massive laser exposure. Despite marked changes in collagen structure, corneal adhesive force was unchanged.

  3. The role of the non-collagenous matrix in tendon function

    PubMed Central

    Thorpe, Chavaunne T; Birch, Helen L; Clegg, Peter D; Screen, Hazel RC

    2013-01-01

    Tendon consists of highly ordered type I collagen molecules that are grouped together to form subunits of increasing diameter. At each hierarchical level, the type I collagen is interspersed with a predominantly non-collagenous matrix (NCM) (Connect. Tissue Res., 6, 1978, 11). Whilst many studies have investigated the structure, organization and function of the collagenous matrix within tendon, relatively few have studied the non-collagenous components. However, there is a growing body of research suggesting the NCM plays an important role within tendon; adaptations to this matrix may confer the specific properties required by tendons with different functions. Furthermore, age-related alterations to non-collagenous proteins have been identified, which may affect tendon resistance to injury. This review focuses on the NCM within the tensional region of developing and mature tendon, discussing the current knowledge and identifying areas that require further study to fully understand structure–function relationships within tendon. This information will aid in the development of appropriate techniques for tendon injury prevention and treatment. PMID:23718692

  4. Effects of Collagen Crosslinking on Bone Material Properties in Health and Disease.

    PubMed

    Saito, Mitsuru; Marumo, Keishi

    2015-09-01

    Data have accumulated to show that various types of collagen crosslinking are implicated in the health of individuals, as well as in a number of disease states, such as osteoporosis, diabetes mellitus, chronic kidney disease, inflammatory bowel disease, or in conditions of mild hyperhomocysteinemia, or when glucocorticoid use is indicated. Collagen crosslinking is a posttranslational modification of collagen molecules and plays important roles in tissue differentiation and in the mechanical properties of collagenous tissue. The crosslinking of collagen in the body can form via two mechanisms: one is enzymatic crosslinking and the other is nonenzymatic crosslinking. Lysyl hydroxylases and lysyl oxidases regulate tissue-specific crosslinking patterns and quantities. Enzymatic crosslinks initially form via immature divalent crosslinking, and a portion of them convert into mature trivalent forms such as pyridinoline and pyrrole crosslinks. Nonenzymatic crosslinks form as a result of reactions which create advanced glycation end products (AGEs), such as pentosidine and glucosepane. These types of crosslinks differ in terms of their mechanisms of formation and function. Impaired enzymatic crosslinking and/or an increase of AGEs have been proposed as a major cause of bone fragility associated with aging and numerous disease states. This review focuses on the effects of collagen crosslinking on bone material properties in health and disease. PMID:25791570

  5. An uncovered XIII century icon: Particular use of organic pigments and gilding techniques highlighted by analytical methods

    NASA Astrophysics Data System (ADS)

    Daveri, Alessia; Doherty, Brenda; Moretti, Patrizia; Grazia, Chiara; Romani, Aldo; Fiorin, Enrico; Brunetti, Brunetto Giovanni; Vagnini, Manuela

    2015-01-01

    The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration.

  6. An uncovered XIII century icon: particular use of organic pigments and gilding techniques highlighted by analytical methods.

    PubMed

    Daveri, Alessia; Doherty, Brenda; Moretti, Patrizia; Grazia, Chiara; Romani, Aldo; Fiorin, Enrico; Brunetti, Brunetto Giovanni; Vagnini, Manuela

    2015-01-25

    The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration. PMID:25105261

  7. 150-kD von Willebrand factor binding protein extracted from human vascular subendothelium is type VI collagen.

    PubMed Central

    Rand, J H; Patel, N D; Schwartz, E; Zhou, S L; Potter, B J

    1991-01-01

    We have previously shown that von Willebrand factor (vWF), a glycoprotein which plays a critical role in the adhesion of platelets to injured blood vessels, is present within vascular subendothelium. We investigated the identity of the subendothelial binding site(s) for vWF by examining vWF binding to subendothelial constituents and solubilized a 150-kD protein with SDS-urea that bound vWF. This protein had an amino-acid composition similar to that of the type VI collagen alpha-1/alpha-2 chains, was recognized by specific polyclonal antibodies against type VI collagen, and had a similar acidic isoelectric point. Furthermore, we found that purified type VI collagen also bound vWF. Thus, we have identified the extracted 150-kD protein as type VI collagen. This protein may play a significant role in the binding of vWF to vascular subendothelium in vivo. Images PMID:2056120

  8. African oil plays

    SciTech Connect

    Clifford, A.J. )

    1989-09-01

    The vast continent of Africa hosts over eight sedimentary basins, covering approximately half its total area. Of these basins, only 82% have entered a mature exploration phase, 9% have had little or no exploration at all. Since oil was first discovered in Africa during the mid-1950s, old play concepts continue to bear fruit, for example in Egypt and Nigeria, while new play concepts promise to become more important, such as in Algeria, Angola, Chad, Egypt, Gabon, and Sudan. The most exciting developments of recent years in African oil exploration are: (1) the Gamba/Dentale play, onshore Gabon; (2) the Pinda play, offshore Angola; (3) the Lucula/Toca play, offshore Cabinda; (4) the Metlaoui play, offshore Libya/Tunisia; (5) the mid-Cretaceous sand play, Chad/Sudan; and (6) the TAG-I/F6 play, onshore Algeria. Examples of these plays are illustrated along with some of the more traditional oil plays. Where are the future oil plays likely to develop No doubt, the Saharan basins of Algeria and Libya will feature strongly, also the presalt of Equatorial West Africa, the Central African Rift System and, more speculatively, offshore Ethiopia and Namibia, and onshore Madagascar, Mozambique, and Tanzania.

  9. The Massive Bleeding after the Operation of Hip Joint Surgery with the Acquired Haemorrhagic Coagulation Factor XIII(13) Deficiency: Two Case Reports.

    PubMed

    Kanda, Akio; Kaneko, Kazuo; Obayashi, Osamu; Mogami, Atsuhiko

    2013-01-01

    Two women, aged 81 and 61, became haemorrhagic after surgery. Their previous surgeries were uneventful with no unexpected bleeding observed. Blood tests prior to the current surgeries indicated normal values including those related to coagulation. There were no problems with the current surgeries prior to leaving the operating room. At 3 hours after the surgery, the 81-year-old patient had an outflow of the drain at 1290 grams and her blood pressure decreased. She had disseminated intravascular coagulation (DIC). The 61-year-old woman had repeated haemorrhages after her current surgery for a long time. Their abnormal haemorrhages were caused by a deficiency of coagulation factor XIII(13). The mechanism of haemorrhagic coagulation factor XIII(13) deficiency is not understood, and it is a rare disorder. The only diagnostic method to detect this disorder is to measure factor XIII(13) activity in the blood. In this paper, we used Arabic and Roman numerals at the same time to avoid confusion of coagulation factor XIII(13) with coagulation factor VIII(8) that causes hemophilia A. PMID:23533879

  10. The dynamics of collagen uncrimping and lateral contraction in tendon and the effect of ionic concentration.

    PubMed

    Buckley, Mark R; Sarver, Joseph J; Freedman, Benjamin R; Soslowsky, Louis J

    2013-09-01

    Under tensile loading, tendon undergoes a number of unique structural changes that govern its mechanical response. For example, stretching a tendon is known to induce both the progressive "uncrimping" of wavy collagen fibrils and extensive lateral contraction mediated by fluid flow out of the tissue. However, it is not known whether these processes are interdependent. Moreover, the rate-dependence of collagen uncrimping and its contribution to tendon's viscoelastic mechanical properties are unknown. Therefore, the objective of this study was to (a) develop a methodology allowing for simultaneous measurement of crimp, stress, axial strain and lateral contraction in tendon under dynamic loading; (b) determine the interdependence of collagen uncrimping and lateral contraction by testing tendons in different swelling conditions; and (c) assess how the process of collagen uncrimping depends on loading rate. Murine flexor carpi ulnaris (FCU) tendons in varying ionic environments were dynamically stretched to a set strain level and imaged through a plane polariscope with the polarizer and analyzer at a fixed angle. Analysis of the resulting images allowed for direct measurement of the crimp frequency and indirect measurement of the tendon thickness. Our findings demonstrate that collagen uncrimping and lateral contraction can occur independently and interstitial fluid impacts tendon mechanics directly. Furthermore, tensile stress, transverse contraction and degree of collagen uncrimping were all rate-dependent, suggesting that collagen uncrimping plays a role in tendon's dynamic mechanical response. This study is the first to characterize the time-dependence of collagen uncrimping in tendon, and establishes structure-function relationships for healthy tendons that can be used to better understand and assess changes in tendon mechanics after disease or injury. PMID:23876711

  11. Fabrication and evaluation of a biodegradable cohesive plug based on reconstituted collagen/γ-polyglutamic acid.

    PubMed

    Hsu, Fu-Yin; Cheng, Ya-Yun; Tsai, Shiao-Wen; Tsai, Wei-Bor

    2010-10-01

    In the past decade, numerous studies have been devoted to developing natural bioadhesives that have the notable capacity to adhere to wet surfaces. Collagen and γ-polyglutamic acid (γ-PGA) are well-known natural hydrophilic polymers that have both been utilized for their versatility in a wide range of biomedical applications. The aim of this study was the construction and characterization of a cohesive plug composed of γ-PGA and reconstituted collagen fibrils crosslinked with water-soluble carbodiimide. Transmission electron microscopy examinations confirmed that the collagen fibrils in the reconstituted collagen/γ-PGA gel retained their native specific D-period structure. This unique D-pattern structure of collagen plays a major role in hemostasis and is also related to several cellular behaviors. The bonding strength of the reconstituted collagen/γ-PGA adhesive was approximately 42.9 ± 4.0 KPa after 5 min of application and increased to 76.5 ± 15.1 KPa after 24 h. This was much stronger than the fibrin adhesive, whose bonding strength was 30.9 ± 0.2 KPa. Furthermore, the reconstituted collagen/γ-PGA gel degraded gradually after subcutaneous implantation in the backs of rats over a period of 8 weeks, without any severe inflammatory response. On the basis of the histological analysis, fibroblasts migrated into the gel while it degraded, which indicates that the gel is not harmful to cellular activity. Together, these findings demonstrate that using reconstituted collagen with retained D-periodicity as a component of the bioadhesive is a possibly better option to formulate effective adhesiveness and is promising as a scaffold for tissue repair. PMID:20665682

  12. The Respiratory Pathogen Moraxella catarrhalis Targets Collagen for Maximal Adherence to Host Tissues

    PubMed Central

    Singh, Birendra; Alvarado-Kristensson, Maria; Johansson, Martin; Hallgren, Oskar; Westergren-Thorsson, Gunilla; Mörgelin, Matthias

    2016-01-01

    ABSTRACT Moraxella catarrhalis is a human respiratory pathogen that causes acute otitis media in children and is associated with exacerbations in patients suffering from chronic obstructive pulmonary disease (COPD). The first step in M. catarrhalis colonization is adherence to the mucosa, epithelial cells, and extracellular matrix (ECM). The objective of this study was to evaluate the role of M. catarrhalis interactions with collagens from various angles. Clinical isolates (n = 43) were tested for collagen binding, followed by a detailed analysis of protein-protein interactions using recombinantly expressed proteins. M. catarrhalis-dependent interactions with collagen produced by human lung fibroblasts and tracheal tissues were studied by utilizing confocal immunohistochemistry and high-resolution scanning electron microscopy. A mouse smoke-induced chronic obstructive pulmonary disease (COPD) model was used to estimate the adherence of M. catarrhalis in vivo. We found that all M. catarrhalis clinical isolates tested adhered to fibrillar collagen types I, II, and III and network-forming collagens IV and VI. The trimeric autotransporter adhesins ubiquitous surface protein A2 (UspA2) and UspA2H were identified as major collagen-binding receptors. M. catarrhalis wild type adhered to human tracheal tissue and collagen-producing lung fibroblasts, whereas UspA2 and UspA2H deletion mutants did not. Moreover, in the COPD mouse model, bacteria devoid of UspA2 and UspA2H had a reduced level of adherence to the respiratory tract compared to the adherence of wild-type bacteria. Our data therefore suggest that the M. catarrhalis UspA2 and UspA2H-dependent interaction with collagens is highly critical for adherence in the host and, furthermore, may play an important role in the establishment of disease. PMID:27006460

  13. Abnormal deposition of collagen/elastic vascular fibres and prognostic significance in idiopathic interstitial pneumonias

    PubMed Central

    Parra, Edwin Roger; Kairalla, Ronaldo Adib; de Carvalho, Carlos Roberto Ribeiro; Capelozzi, Vera Luiza

    2007-01-01

    Background Vascular remodelling has recently been shown to be a promising pathogenetic indicator in idiopathic interstitial pneumonias (IIPs). Aim To validate the importance of the collagen/elastic system in vascular remodelling and to study the relationships between the collagen/elastic system, survival and the major histological patterns of IIPs. Methods Collagen/elastic system fibres were studied in 25 patients with acute interstitial pneumonia/diffuse alveolar damage, 22 with non‐specific interstitial pneumonia/non‐specific interstitial pneumonia and 55 with idiopathic pulmonary fibrosis/usual interstitial pneumonia. The Picrosirius polarisation method and Weigert's resorcin–fuchsin histochemistry and morphometric analysis were used to evaluate the amount of vascular collagen/elastic system fibres and their association with the histological pattern of IIPs. The association between vascular remodelling and the degree of parenchymal fibrosis in usual interstitial pneumonia (UIP) was also considered. Results The vascular measurement of collagen/elastic fibres was significantly higher in UIP than in the lungs of controls, and in those with diffuse alveolar damage and those with non‐specific interstitial pneumonia. In addition, the increment of collagen/elastic fibres in UIP varied according to the degree and activity of the parenchymal fibrosis. The most important predictors of survival in UIP were vascular remodelling classification and vascular collagen deposition. Conclusion A progressive vascular fibroelastosis occurs in IIP histological patterns, probably indicating evolutionarily adapted responses to parenchymal injury. The vascular remodelling classification and the increase in vascular collagen were related to survival in IIP and possibly play a role in its pathogenesis. Further studies are needed to determine whether this relationship is causal or consequential. PMID:17251318

  14. Surface characterization of collagen/elastin based biomaterials for tissue regeneration

    NASA Astrophysics Data System (ADS)

    Skopinska-Wisniewska, J.; Sionkowska, A.; Kaminska, A.; Kaznica, A.; Jachimiak, R.; Drewa, T.

    2009-07-01

    Collagen and elastin are the main proteins of extracellular matrix. Collagen plays a crucial role in tensile strength of tissues, whereas elastin provides resilience to many organs. Both biopolymers are readily available and biocompatible. These properties point out that collagen and elastin are good components of materials for many potential medical applications. The surface properties of biomaterials play an important role in biomedicine as the majority of biological reactions occur on the surface of implanted materials. One of the methods of surface modification is UV-irradiation. The exposition of the biomaterial on ultraviolet light can alterate surface properties of the materials, their chemical stability, swelling properties and mechanical properties as well. The aim of our work was to study the surface properties and biocompatibility of new collagen/elastin based biomaterials and consideration of the influence of ultraviolet light on these properties. The surface properties of collagen/elastin based biomaterials modified by UV-irradiation were studied using the technique of atomic force microscopy (AFM) and contact angle measurements. On the basis of the results the surface free energy and its polar component was calculated using Owens-Wendt method. To assess the biological performance of films based on collagen, elastin and their blends, the response of 3T3 cell was investigated. It was found that the surface of collagen/elastin film is enriched in less polar component - collagen. Exposition on UV light increases polarity of collagen/elastin based films, due to photooxidation process. The AFM images have shown that topography and roughness of the materials had been also affected by UV-irradiation. The changes in surface properties influence on interaction between the material's surface and cells. The investigation of 3T3 cells grown on films based on collagen, elastin and their blends, leads to the conclusion that higher content of elastin in biomaterial

  15. Structural and functional influences of coagulation factor XIII subunit B heterozygous missense mutants

    PubMed Central

    Thomas, Anne; Biswas, Arijit; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2015-01-01

    The coagulation factor XIII(FXIII) is a plasma circulating heterotetrameric protransglutaminase that acts at the end of the coagulation cascade by covalently cross-linking preformed fibrin clots (to themselves and to fibrinolytic inhibitors) in order to stabilize them against fibrinolysis. It circulates in the plasma as a heterotetramer composed of two homomeric catalytic Factor XIIIA2 (FXIIIA2) and two homomeric protective/carrier Factor XIIIB2 subunit (FXIIIB2). Congenital deficiency of FXIII is of two types: severe homozygous/compound heterozygous FXIII deficiency which results in severe bleeding symptoms and mild heterozygous FXIII deficiency which is associated with mild bleeding (only upon trauma) or an asymptomatic phenotype. Defects in the F13B gene (Factor XIIIB subunit) occur more frequently in mild FXIII deficiency patients than in severe FXIII deficiency. We had recently reported secretion-related defects for seven previously reported F13B missense mutations. In the present study we further analyze the underlying molecular pathological mechanisms as well as the heterozygous expression phenotype for these mutations using a combination of in vitro heterologous expression (in HEK293T cells) and confocal microscopy. In combination with the in vitro work we have also performed an in silico solvated molecular dynamic simulation study on previously reported FXIIIB subunit sushi domain homology models in order to predict the putative structure-functional impact of these mutations. We were able to categorize the mutations into the following functional groups that: (1) affect antigenic stability as well as binding to FXIIIA subunit, that is, Cys5Arg, Cys316Phe, and Pro428Ser (2) affect binding to FXIIIA subunit with little or no influence on antigenic stability, that is, Ile81Asn and Val401Gln c) influence neither aspects and are most likely causality linked polymorphisms or functional polymorphisms, that is, Leu116Phe and Val217Ile. The Cys5Arg mutation was the

  16. Structural and functional influences of coagulation factor XIII subunit B heterozygous missense mutants.

    PubMed

    Thomas, Anne; Biswas, Arijit; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2015-07-01

    The coagulation factor XIII(FXIII) is a plasma circulating heterotetrameric protransglutaminase that acts at the end of the coagulation cascade by covalently cross-linking preformed fibrin clots (to themselves and to fibrinolytic inhibitors) in order to stabilize them against fibrinolysis. It circulates in the plasma as a heterotetramer composed of two homomeric catalytic Factor XIIIA2 (FXIIIA2) and two homomeric protective/carrier Factor XIIIB2 subunit (FXIIIB2). Congenital deficiency of FXIII is of two types: severe homozygous/compound heterozygous FXIII deficiency which results in severe bleeding symptoms and mild heterozygous FXIII deficiency which is associated with mild bleeding (only upon trauma) or an asymptomatic phenotype. Defects in the F13B gene (Factor XIIIB subunit) occur more frequently in mild FXIII deficiency patients than in severe FXIII deficiency. We had recently reported secretion-related defects for seven previously reported F13B missense mutations. In the present study we further analyze the underlying molecular pathological mechanisms as well as the heterozygous expression phenotype for these mutations using a combination of in vitro heterologous expression (in HEK293T cells) and confocal microscopy. In combination with the in vitro work we have also performed an in silico solvated molecular dynamic simulation study on previously reported FXIIIB subunit sushi domain homology models in order to predict the putative structure-functional impact of these mutations. We were able to categorize the mutations into the following functional groups that: (1) affect antigenic stability as well as binding to FXIIIA subunit, that is, Cys5Arg, Cys316Phe, and Pro428Ser (2) affect binding to FXIIIA subunit with little or no influence on antigenic stability, that is, Ile81Asn and Val401Gln c) influence neither aspects and are most likely causality linked polymorphisms or functional polymorphisms, that is, Leu116Phe and Val217Ile. The Cys5Arg mutation was the

  17. Cloning of an annelid fibrillar-collagen gene and phylogenetic analysis of vertebrate and invertebrate collagens.

    PubMed

    Sicot, F X; Exposito, J Y; Masselot, M; Garrone, R; Deutsch, J; Gaill, F

    1997-05-15

    Arenicola marina possesses cuticular and interstitial collagens, which are mostly synthesised by its epidermis. A cDNA library was constructed from the body wall. This annelid cDNA library was screened with a sea-urchin-collagen cDNA probe, and several overlapping clones were isolated. Nucleotide sequencing of these clones revealed an open reading frame of 2052 nucleotides. The translation product exhibits a triple helical domain of 138 Gly-Xaa-Yaa repeats followed by a 269-residue-long C-terminal non-collagenous domain (C-propeptide). The triple helical domain exhibits an imperfection that has been previously described in a peptide produced by cyanogen bromide digestion (CNBr peptide) of A. marina interstitial collagen. This imperfection occurs at the same place in the interstitial collagen of the vestimentiferan Riftia pachyptila. This identifies the clone as coding for the C-terminal part of a fibrillar collagen chain. It was called FAm1alpha, for fibrillar collagen 1alpha chain of A. marina. The non-collagenous domain possesses a structure similar to carboxy-terminal propeptides of fibrillar pro-alpha chains. Only six conserved cysteine residues are observed in A. marina compared with seven or eight in all other known C-propeptides. This provides information on the importance of disulfide bonds in C-propeptide interactions and in the collagen-assembly process. Phylogenetic studies indicate that the fibrillar collagen 1alpha chain of A. marina is homologous to the R. pachyptila interstitial collagen and that the FAm1alpha gene evolved independently from the other alpha-chain genes. Complementary analyses indicate that the vertebrate fibrillar collagen family is composed of two monophyletic subgroups with a specific position of the collagen type-V chains. PMID:9210465

  18. The Mineral–Collagen Interface in Bone

    PubMed Central

    2015-01-01

    The interface between collagen and the mineral reinforcement phase, carbonated hydroxyapatite (cAp), is essential for bone’s remarkable functionality as a biological composite material. The very small dimensions of the cAp phase and the disparate natures of the reinforcement and matrix are essential to the material’s performance but also complicate study of this interface. This article summarizes what is known about the cAp-collagen interface in bone and begins with descriptions of the matrix and reinforcement roles in composites, of the phases bounding the interface, of growth of cAp growing within the collagen matrix, and of the effect of intra- and extrafibrilar mineral on determinations of interfacial properties. Different observed interfacial interactions with cAp (collagen, water, non-collagenous proteins) are reviewed; experimental results on interface interactions during loading are reported as are their influence on macroscopic mechanical properties; conclusions of numerical modeling of interfacial interactions are also presented. The data suggest interfacial interlocking (bending of collagen molecules around cAp nanoplatelets) and water-mediated bonding between collagen and cAp are essential to load transfer. The review concludes with descriptions of areas where new research is needed to improve understanding of how the interface functions. PMID:25824581

  19. Single-molecule studies of collagen mechanics

    NASA Astrophysics Data System (ADS)

    Forde, Nancy; Rezaei, Naghmeh; Kirkness, Michael

    Collagen is the fundamental structural protein in vertebrates. Its triple helical structure at the molecular level is believed to be strongly related to its mechanical role in connective tissues. However, the mechanics of collagen at the single-molecule level remain contentious. Estimates of its persistence length span an order of magnitude, from 15-180 nm for this biopolymer of 300 nm contour length. How collagen responds to applied force is also controversial, with different single-molecule studies suggesting one of three different responses: extending entropically, overwinding, or unwinding, all at forces below 10 pN. Using atomic force microscopy to image collagens deposited from solution, we find that their flexibility depends strongly on ionic strength and pH. To study force-dependent structural changes, we are performing highly parallelized enzymatic cleavage assays of triple helical collagen in our new compact centrifuge force microscope. Because proteolytic cleavage requires a locally unwound triple helix, these experiments are revealing how local collagen structure changes in response to applied force. Our results can help to resolve long-standing debates about collagen mechanics and structure at the molecular level.

  20. Age-related crosslink in skin collagen

    SciTech Connect

    Yamauchi, M.; Mechanic, G.

    1986-05-01

    A stable crosslinking amino acid was isolated from mature bovine skin collagen and its structure was identified as histidinohydroxylysinonorleucine (HHL) using fast atom bombardment mass spectrometry and /sup 1/H, /sup 13/C-NMR. This newly identified crosslink has a linkage between C-2 histidine and C-6 of lysine in the latter's portion of hydroxylysinonorleucine. Quantitative studies using various aged samples of cow and human skin collagen indicated that this acid-heat stable nonreducible compound was the major age-related crosslink. In case of cow skin collagen, for example, during early embryonic development (3 and 5 month old embryos) the content of HHL stayed less than 0.01 residue/mole of collagen, however from the middle of gestation period (7 month old embryo) through the maturation stage it showed rapid increase with age and reached approximately 0.5 residues/mole of collagen in the 3 year old animal. Small increments (up to 0.65 res/mole of collagen) were observed in the 9 year old cow. The amounts of the crosslink unlike pyridinoline do not decrease with aging. Similar patterns were observed in human skin collagen.

  1. Collagen-platelet interactions: recognition and signalling.

    PubMed

    Farndale, Richard W; Siljander, Pia R; Onley, David J; Sundaresan, Pavithra; Knight, C Graham; Barnes, Michael J

    2003-01-01

    The collagen-platelet interaction is central to haemostasis and may be a critical determinant of arterial thrombosis, where subendothelium is exposed after rupture of atherosclerotic plaque. Recent research has capitalized on the cloning of an important signalling receptor for collagen, glycoprotein VI, which is expressed only on platelets, and on the use of collagen-mimetic peptides as specific tools for both glycoprotein VI and integrin alpha 2 beta 1. We have identified sequences, GPO and GFOGER (where O denotes hydroxyproline), within collagen that are recognized by the collagen receptors glycoprotein VI and integrin alpha 2 beta 1 respectively, allowing their signalling properties and specific functional roles to be examined. Triple-helical peptides containing these sequences were used to show the signalling potential of integrin alpha 2 beta 1, and to confirm its important contribution to platelet adhesion. Glycoprotein VI appears to operate functionally on the platelet surface as a dimer, which recognizes GPO motifs that are separated by four triplets of collagen sequence. These advances will allow the relationship between the structure of collagen and its haemostatic activity to be established. PMID:14587284

  2. Nanoscale Mechanics of Type I Collagen

    NASA Astrophysics Data System (ADS)

    Harper, H.; Cropper, E.; Bulger, A.; Choksi, U.; Koob, T. J.; Pandit, S.; Matthews, W. G.

    2009-03-01

    Collagen is the most abundant protein in the body by mass. Type I collagen fibrils provide mechanical strength and cellular housing within tissues exhibiting a broad range of mechanical properties. This diversity in the mechanics of tissues with similar underlying components warrants detailed study of the process by which structure and mechanics develop. While collagen mechanics have been studied at the tissue level for decades, surprising little is known about collagen mechanics at the fibril and molecular level. Presented herein is a multi-scale experimental and computational investigation of collagen I mechanics, bridging the single molecule and fibril hierarchal forms. The mechanics of single collagen molecules are explored using AFM and force spectroscopy. Moreover, atomistic molecular-dynamics simulations are performed to provide structural information not accessible to the experimental system. Fibrils then are grown from molecular collagen, and the mechanics of these fibrils are investigated using AFM. Based upon the single molecule and fibril results, a coarse-grain computational model is being developed. The outcomes include a better understanding of how the mechanics of filamentous self-organizing systems are derived and how their hierarchical forms are established.

  3. Fatal coccidioidomycosis in collagen vascular diseases.

    PubMed

    Johnson, W M; Gall, E P

    1983-02-01

    Ten patients who died from coccidioidomycosis in Arizona from 1968 to 1975 had underlying collagen vascular diseases: 4 with rheumatoid arthritis, 4 with systemic lupus erythematosus, and 2 with dermatomyositis. All 10 patients had been treated with corticosteroids; 2 were taking cytotoxic drugs. Collagen vascular diseases and the use of corticosteroids and cytotoxic drugs may be associated with the depression of cell-mediated immunity. The potential for opportunistic coccidioidomycosis should be noted when corticosteroids and cytotoxic drugs are used for treating collagen vascular disease in patients residing in or coming from areas where coccidioidomycosis is endemic. PMID:6842490

  4. Collagen plug occlusion of Molteno tube shunts.

    PubMed

    Stewart, W; Feldman, R M; Gross, R L

    1993-01-01

    We report five patients in whom collagen lacrimal plugs were used to temporarily occlude the lumen of Molteno shunts to prevent early postoperative hypotony. Only one eye, with a double plate, developed hypotony and a flat anterior chamber that required reformation. However, in three patients, the collagen plugs did not dissolve and had to be removed surgically to lower the intraocular pressure. Although the semipermeability of collagen is desirable, its unpredictable degradation renders it unsuitable for temporary occlusion of tube shunts. Other biodegradable materials may be more appropriate for this purpose. PMID:8446334

  5. Collagen stability, hydration and native state.

    PubMed

    Mogilner, Inés G; Ruderman, Graciela; Grigera, J Raúl

    2002-12-01

    Molecular dynamics simulations of a collagen-like peptide (Pro-Hyp-Gly)4-Pro-Hyp-Ala-(Pro-Hyp-Gly)5 have been done in order to study the contribution of the hydration structure on keeping the native structure of collagen. The simulation shows that the absence of water produces a distortion on the molecular conformation and an increase in the number of intra-molecular hydrogen bonds. This is in agreement with previous experimental results showing the stiffness of collagen under severe drying and its increase in the thermal stability. This dehydrated material does not keep, however, the native structure. PMID:12463639

  6. Play and Digital Media

    ERIC Educational Resources Information Center

    Johnson, James E.; Christie, James F.

    2009-01-01

    This article examines how play is affected by computers and digital toys. Research indicates that when computer software targeted at children is problem-solving oriented and open-ended, children tend to engage in creative play and interact with peers in a positive manner. On the other hand, drill-and-practice programs can be quite boring and limit…

  7. Let's Just Play

    ERIC Educational Resources Information Center

    Schmidt, Janet

    2003-01-01

    Children have a right to play. The idea is so simple it seems self-evident. But a stroll through any toy superstore, or any half-hour of so-called "children's" programming on commercial TV, makes it clear that violence, not play, dominates what's being sold. In this article, the author discusses how teachers and parents share the responsibility in…

  8. Family Play Therapy.

    ERIC Educational Resources Information Center

    Ariel, Shlomo

    This paper examines a case study of family play therapy in Israel. The unique contributions of play therapy are evaluated including the therapy's accessibility to young children, its richness and flexibility, its exposure of covert patterns, its wealth of therapeutic means, and its therapeutic economy. The systematization of the therapy attempts…

  9. Clinical Intuition at Play

    ERIC Educational Resources Information Center

    Marks-Tarlow, Terry

    2014-01-01

    A clinical psychologist and consulting psychotherapist discusses how elements of play, inherent in the intuition required in analysis, can provide a cornerstone for serious therapeutic work. She argues that many aspects of play--its key roles in human development, individual growth, and personal creativity, among others--can help therapists and…

  10. Intergenerational Learning through Play.

    ERIC Educational Resources Information Center

    Davis, Lindsay; Larkin, Elizabeth; Graves, Stephen B.

    2002-01-01

    Argues that shared play experiences are a good way to build mutually beneficial relationships among older and younger generations. Outlines why intergenerational play is important, focusing on its cognitive, social, physical, and emotional benefits for both older adults and young children. Describes toys, materials, and games conducive to positive…

  11. Poetry and Play.

    ERIC Educational Resources Information Center

    Law, Richard A.

    Philosophers and poets from classical times to the present have argued that playful and amiable discourse are conducive to teaching and learning. The play principle enhances reading and study and should be applied by teachers to benefit their students. Teachers should help their students see that it is fun to enliven the imagination with good…

  12. The Fear of Play

    ERIC Educational Resources Information Center

    Almon, Joan

    2009-01-01

    Real play--play that is initiated and directed by children and that bubbles up from within the child rather than being imposed by adults--has largely disappeared from the landscape of childhood in the United States. There are many reasons for this, such as the long hours spent in front of screens each day or in activities organized by adults. In…

  13. Return to Play

    ERIC Educational Resources Information Center

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  14. Role Playing and Skits

    ERIC Educational Resources Information Center

    Letwin, Robert, Ed.

    1975-01-01

    Explores non-scripted role playing, dialogue role playing, sociodrama, and skits as variations of simulation techniques. Provides step-by-step guidelines for conducting such sessions. Successful Meetings, Bill Communications, Inc., 1422 Chestnut Street, Philadelphia, Pa. 19102. Subscription Rates: yearly (US, Canada, Mexico) $14.00; elsewhere,…

  15. Play as Experience

    ERIC Educational Resources Information Center

    Henricks, Thomas S.

    2015-01-01

    The author investigates what he believes one of the more important aspects of play--the experience it generates in its participants. He considers the quality of this experience in relation to five ways of viewing play--as action, interaction, activity, disposition, and within a context. He treats broadly the different forms of affect, including…

  16. Playing with Autistic Children.

    ERIC Educational Resources Information Center

    Casner, Mary W.; Marks, Susan F.

    The paper looks at the development of a play group for autistic children with descriptions of the autistic population, the daily program, the program's philosophy, the play group model, and actual lessons. Children, who ranged in age from 5 to 9 years, often chose activities which were self-stimulating and/or repetitive. The daily program included…

  17. Television at Play.

    ERIC Educational Resources Information Center

    Reid, Leonard N.; Frazer, Charles F.

    1980-01-01

    Discusses children as television viewers capable of manipulating the co-viewing setting by interpreting, constructing, and carrying out planned lines of play in relation to television and its content. Examples illustrate program-oriented and free-form improvisational play situations. (JMF)

  18. Supramolecular assembly of collagen fibrils into collagen fiber in fish scales of red seabream, Pagrus major.

    PubMed

    Youn, Hwa Shik; Shin, Tae Joo

    2009-11-01

    Supramolecular assembly of collagen fibrils into collagen fiber and its distribution in fish scales of red seabream, Pagrus major, were investigated. By virtue of Zernike phase-contrast hard X-ray microscopy, it has been firstly observed that collagen fiber consists of helical substructures of collagen fibrils wrapped with incrustation. As it close to the scalar focus (that is, with aging), loosened- and deteriorated-helical assemblies started to be observed with loosing wrapping incrustation, indicative of the distortion of the basic helical assembly. Various distributions and packing arrangements of collagen fibers were observed dependent on subdivisions of fish scale. Freshly growing edge region of fish scale, embedded into fish skin, showed rarely patched and one directionally arranged collagen fibers, in which specifically triple helical assemblies of collagen fibrils were found. On the contrary, relatively aged region of the rostral field close to the scalar focus displayed randomly directed and densely packed collagen fibers, in which loosened- and deteriorated-helical assemblies of collagen fibrils were mostly found. Our results have demonstrated that hard X-ray microscope can be a powerful tool to study in situ internal structure of biological specimens in an atmospheric pressure. PMID:19666125

  19. Harnessing the Versatility of Bacterial Collagen to Improve the Chondrogenic Potential of Porous Collagen Scaffolds.

    PubMed

    Parmar, Paresh A; St-Pierre, Jean-Philippe; Chow, Lesley W; Puetzer, Jennifer L; Stoichevska, Violet; Peng, Yong Y; Werkmeister, Jerome A; Ramshaw, John A M; Stevens, Molly M

    2016-07-01

    Collagen I foams are used in the clinic as scaffolds to promote articular cartilage repair as they provide a bioactive environment for cells with chondrogenic potential. However, collagen I as a base material does not allow for precise control over bioactivity. Alternatively, recombinant bacterial collagens can be used as "blank slate" collagen molecules to offer a versatile platform for incorporation of selected bioactive sequences and fabrication into 3D scaffolds. Here, we show the potential of Streptococcal collagen-like 2 (Scl2) protein foams modified with peptides designed to specifically and noncovalently bind hyaluronic acid and chondroitin sulfate to improve chondrogenesis of human mesenchymal stem cells (hMSCs) compared to collagen I foams. Specific compositions of functionalized Scl2 foams lead to improved chondrogenesis compared to both nonfunctionalized Scl2 and collagen I foams, as indicated by gene expression, extracellular matrix accumulation, and compression moduli. hMSCs cultured in functionalized Scl2 foams exhibit decreased collagens I and X gene and protein expression, suggesting an advantage over collagen I foams in promoting a chondrocytic phenotype. These highly modular foams can be further modified to improve specific aspects chondrogenesis. As such, these scaffolds also have the potential to be tailored for other regenerative medicine applications. PMID:27219220

  20. Collagen Accumulation in Osteosarcoma Cells lacking GLT25D1 Collagen Galactosyltransferase.

    PubMed

    Baumann, Stephan; Hennet, Thierry

    2016-08-26

    Collagen is post-translationally modified by prolyl and lysyl hydroxylation and subsequently by glycosylation of hydroxylysine. Despite the widespread occurrence of the glycan structure Glc(α1-2)Gal linked to hydroxylysine in animals, the functional significance of collagen glycosylation remains elusive. To address the role of glycosylation in collagen expression, folding, and secretion, we used the CRISPR/Cas9 system to inactivate the collagen galactosyltransferase GLT25D1 and GLT25D2 genes in osteosarcoma cells. Loss of GLT25D1 led to increased expression and intracellular accumulation of collagen type I, whereas loss of GLT25D2 had no effect on collagen secretion. Inactivation of the GLT25D1 gene resulted in a compensatory induction of GLT25D2 expression. Loss of GLT25D1 decreased collagen glycosylation by up to 60% but did not alter collagen folding and thermal stability. Whereas cells harboring individually inactivated GLT25D1 and GLT25D2 genes could be recovered and maintained in culture, cell clones with simultaneously inactive GLT25D1 and GLT25D2 genes could be not grown and studied, suggesting that a complete loss of collagen glycosylation impairs osteosarcoma cell proliferation and viability. PMID:27402836

  1. Studies on fish scale collagen of Pacific saury (Cololabis saira).

    PubMed

    Mori, Hideki; Tone, Yurie; Shimizu, Kouske; Zikihara, Kazunori; Tokutomi, Satoru; Ida, Tomoaki; Ihara, Hideshi; Hara, Masayuki

    2013-01-01

    We purified and characterized Type I collagen from the scales of the Pacific saury (Cololabis saira) and compared it with collagen from other organisms. Subunit composition of C. saira collagen (2α1+α2) was similar to that of red sea bream (Pagrus major) and porcine collagen. C. saira collagen did not form a firm gel after neutralization of pH in solution. The temperature of denaturation (24-25 °C) of C. saira collagen was slightly lower than that of P. major collagen (26-27 °C). The contents of proline and hydroxyproline were lower in red sea bream and Pacific saury collagen than in porcine collagen. Circular dichroism spectra and Fourier-transformed infrared spectra showed that heat denaturation caused unfolding of the triple helices in all three collagens. PMID:25428059

  2. Marine Collagen: An Emerging Player in Biomedical applications.

    PubMed

    Subhan, Fazli; Ikram, Muhammad; Shehzad, Adeeb; Ghafoor, Abdul

    2015-08-01

    Mammalian collagen is a multifactorial biomaterial that is widely used for beneficial purposes in the advanced biomedical technologies. Generally, biomedical applicable collagen is extracted from the mammalian body, but it can also be derived from marine species. Recently, mammalian tissues collagen proteins are considered a great pathological risk for transmitted diseases, because purification of such protein is very challenging and needs efficient tool to avoid structure alteration. Thus, difficult extraction process and high cost decreased mammalian collagen demands for beneficial effects compared to marine collagen. In contrast, marine collagen is safe and easy to extract, however this potential source of collagen is hindered by low denaturing temperature, which is considered a main hurdle in the beneficial effects of marine collagen. Characterization and biomedical applications of marine collagen are in transition state and yet to be discovered. Therefore, an attempt was made to summarize the recent knowledge regarding different aspects of marine collagen applications in the biomedical engineering field. PMID:26243892

  3. Unusual Fragmentation Pathways in Collagen Glycopeptides

    NASA Astrophysics Data System (ADS)

    Perdivara, Irina; Perera, Lalith; Sricholpech, Marnisa; Terajima, Masahiko; Pleshko, Nancy; Yamauchi, Mitsuo; Tomer, Kenneth B.

    2013-07-01

    Collagens are the most abundant glycoproteins in the body. One characteristic of this protein family is that the amino acid sequence consists of repeats of three amino acids -(X—Y—Gly)n. Within this motif, the Y residue is often 4-hydroxyproline (HyP) or 5-hydroxylysine (HyK). Glycosylation in collagen occurs at the 5-OH group in HyK in the form of two glycosides, galactosylhydroxylysine (Gal-HyK) and glucosyl galactosylhydroxylysine (GlcGal-HyK). In collision induced dissociation (CID), collagen tryptic glycopeptides exhibit unexpected gas-phase dissociation behavior compared to typical N- and O-linked glycopeptides (i.e., in addition to glycosidic bond cleavages, extensive cleavages of the amide bonds are observed). The Gal- or GlcGal- glycan modifications are largely retained on the fragment ions. These features enable unambiguous determination of the amino acid sequence of collagen glycopeptides and the location of the glycosylation site. This dissociation pattern was consistent for all analyzed collagen glycopeptides, regardless of their length or amino acid composition, collagen type or tissue. The two fragmentation pathways—amide bond and glycosidic bond cleavage—are highly competitive in collagen tryptic glycopeptides. The number of ionizing protons relative to the number of basic sites (i.e., Arg, Lys, HyK, and N-terminus) is a major driving force of the fragmentation. We present here our experimental results and employ quantum mechanics calculations to understand the factors enhancing the labile character of the amide bonds and the stability of hydroxylysine glycosides in gas phase dissociation of collagen glycopeptides.

  4. Dermal ultrastructure in collagen VI myopathy.

    PubMed

    Hermanns-Lê, Trinh; Piérard, Gérald E; Piérard-Franchimont, Claudine; Delvenne, Philippe

    2014-04-01

    The COL VI mutations are responsible for a spectrum of myopathies. The authors report cutaneous ultrastructural alterations in a patient with COL6A2 myopathy. The changes include variations in size of collagen fibrils, flower-like sections of collagen fibrils, as well as thickening of vessel and nerve basement membranes. Electron microscopy of a skin biopsy contributes to the diagnosis of COL VI myopathies. PMID:24134684

  5. Techniques for Type I Collagen Organization

    NASA Astrophysics Data System (ADS)

    Anderson-Jackson, LaTecia Diamond

    Tissue Engineering is a process in which cells, engineering, and material methods are used in amalgamation to improve biological functions. The purpose of tissue engineering is to develop alternative solutions to treat or cure tissues and organs that have been severely altered or damaged by diseases, congenital defects, trauma, or cancer. One of the most common and most promising biological materials for tissue engineering to develop scaffolds is Type I collagen. A major challenge in biomedical research is aligning Type I collagen to mimic biological structures, such as ligaments, tendons, bones, and other hierarchal aligned structures within the human body. The intent of this research is to examine possible techniques for organizing Type I collagen and to assess which of the techniques is effective for potential biological applications. The techniques used in this research to organize collagen are soft lithography with solution-assisted sonication embossing, directional freezing, and direct poling. The final concentration used for both soft lithography with solution-assisted sonication embossing and direct poling was 1 mg/ml, whereas for directional freezing the final concentration varied between 4mg/ml, 2mg/ml, and 1 mg/ml. These techniques were characterized using the Atomic Force Microscope (AFM) and Helium Ion Microscope (HIM). In this study, we have found that out of the three techniques, the soft lithography and directional freezing techniques have been successful in organizing collagen in a particular pattern, but not alignment. We concluded alignment may be dependent on the pH of collagen and the amount of acetic acid used in collagen solution. However, experiments are still being conducted to optimize all three techniques to align collagen in a unidirectional arrangement.

  6. Corneal Collagen Cross-Linking

    PubMed Central

    Jankov II, Mirko R.; Jovanovic, Vesna; Nikolic, Ljubisa; Lake, Jonathan C.; Kymionis, Georgos; Coskunseven, Efekan

    2010-01-01

    Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) is a new technique of corneal tissue strengthening by using riboflavin as a photosensitizer and UVA to increase the formation of intra and interfibrillar covalent bonds by photosensitized oxidation. Keratocyte apoptosis in the anterior segment of the corneal stroma all the way down to a depth of about 300 microns has been described and a demarcation line between the treated and untreated cornea has been clearly shown. It is important to ensure that the cytotoxic threshold for the endothelium has not been exceeded by strictly respecting the minimal corneal thickness. Confocal microscopy studies show that repopulation of keratocytes is already visible 1 month after the treatment, reaching its pre-operative quantity and quality in terms of functional morphology within 6 months after the treatment. The major indication for the use of CXL is to inhibit the progression of corneal ectasias, such as keratoconus and pellucid marginal degeneration. CXL may also be effective in the treatment and prophylaxis of iatrogenic keratectasia, resulting from excessively aggressive photoablation. This treatment has also been used to treat infectious corneal ulcers with apparent favorable results. Combination with other treatments, such as intracorneal ring segment implantation, limited topography-guided photoablation and conductive keratoplasty have been used with different levels of success. PMID:20543933

  7. [Ossification of the collagen implant].

    PubMed

    Walter, M; Müller, J M; Keller, H W; Brenner, U

    1985-12-01

    Native collagen type I was studied morphologically and fluorescent-histologically after implantation in bony defects. As criteria for revitalisation we used depth and density of immigration, type of immigrated cells, revascularisation, formation of new cartilage and bone. Furthermore the deposition of fluorochromes was studied. The maximum of cellular immigration was reached after 8 weeks and remained at this level for the period of observation. The implants were impregnated only with fibroblasts and fibrocytes, developing into chondroblasts, chondrocytes, osteoblasts and osteocytes. Only in one case basophilic round-cells could be seen. The centres of the implants were after 6 weeks rarely, after 8 weeks fully revascularized. Formation of new cartilage and bone could be seen after 6 weeks, increasing in number and extension during the observation-period. Osteoneogenesis was performed both by desmal and enchondral ossification, enchondral ossification much more in evidence. The deposition of fluorochromes could be seen in each implant. After 8 weeks fluorochromes could only be seen at the bone-implant interface, after 12 and 16 weeks even the centres were well impregnated. In a single case reossification in a control-rib could be seen as well morphologically as fluorescent-histologically. PMID:2868614

  8. Collagen-like antimicrobial peptides.

    PubMed

    Masuda, Ryo; Kudo, Masakazu; Dazai, Yui; Mima, Takehiko; Koide, Takaki

    2016-11-01

    Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453-459, 2016. PMID:27271210

  9. Marine Origin Collagens and Its Potential Applications

    PubMed Central

    Silva, Tiago H.; Moreira-Silva, Joana; Marques, Ana L. P.; Domingues, Alberta; Bayon, Yves; Reis, Rui L.

    2014-01-01

    Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role, existing different types according with their specific organization in distinct tissues. From this, they have been elected as one of the key biological materials in tissue regeneration approaches. Also, industry is constantly searching for new natural sources of collagen and upgraded methodologies for their production. The most common sources are from bovine and porcine origin, but other ways are making their route, such as recombinant production, but also extraction from marine organisms like fish. Different organisms have been proposed and explored for collagen extraction, allowing the sustainable production of different types of collagens, with properties depending on the kind of organism (and their natural environment) and extraction methodology. Such variety of collagen properties has been further investigated in different ways to render a wide range of applications. The present review aims to shed some light on the contribution of marine collagens for the scientific and technological development of this sector, stressing the opportunities and challenges that they are and most probably will be facing to assume a role as an alternative source for industrial exploitation. PMID:25490254

  10. Collagen shield delivery of amphotericin B.

    PubMed

    Schwartz, S D; Harrison, S A; Engstrom, R E; Bawdon, R E; Lee, D A; Mondino, B J

    1990-06-15

    By using a high-pressure liquid chromatography assay, we investigated the ability of collagen shield therapeutic contact lenses to release amphotericin B and deliver it to the anterior segment of rabbit eyes. In vitro studies showed that presoaked collagen shields released most of the amphotericin B within the first hour of elution. We compared the corneal and aqueous humor amphotericin B levels produced by collagen shields soaked in amphotericin B and frequent-drop therapy at four time points over a six-hour period. The collagen shields soaked in amphotericin B produced corneal levels that were higher than those produced by frequent-drop therapy at one hour, equivalent to drop therapy at two and three hours, and lower than drop therapy at six hours. There were no differences in amphotericin B levels in aqueous humor at any time point between rabbits treated with collagen shield delivery and rabbits treated with frequent-drop delivery. The results of this study suggest that amphotericin B delivery to the cornea by collagen shields is comparable to frequent-drop delivery but has the potential benefit of added convenience and compliance. PMID:2346199

  11. Evaluation of collagen immobilized to silicon plates by ion beam

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Kobayashi, T.; Iwaki, M.

    2006-01-01

    A study has been made of immobilization of collagen coated on the substrate by ion beam in order to elucidate the effects of ion bombardment on cell adhesion strength. Substrates used were silicon plates, on which 0.3% type-I collagen solution was coated using a spin coater. The collagen-coated silicon was bombarded with 50 keV He+ ions at doses from 1 × 1013 to 1 × 1015 ions/cm2 using a RIKEN TK-100 ion implanter. The collagen-immobilized specimens were mounted on a parallel-plate flow chamber to perform the collagen adhesion tests with a flowing shear stress. Morphological observations of collagen were performed by scanning transmission electron microscopy (STEM). The chemical condition of collagen was detected by X-ray photoelectron spectroscopy (XPS). The collagen layer in the non-bombarded specimen was about 20 nm in thickness. STEM micrographs showed that collagen layer has thinned due to contraction by ion bombardment as the dose increased. After the collagen adhesion test, collagen layer surface with the non-bombarded specimen was peeled off by shear stress. As the dose increased, the detachment of collagen was suppressed. Detachment of collagen was hardly observed for the dose of 1 × 1015 ions/cm2. The XPS results of collagen structures showed that ion bombardment generated new bonds between collagen molecules in the collagen layer. It is concluded that the increase of collagen adhesion at higher doses is due to the ion-beam immobilization of collagen molecules resulting from new bond generation by displaced atoms and excited atoms between collagen molecules in the collagen layer.

  12. Patho-epidemiological study on Genotype-XIII Newcastle disease virus infection in commercial vaccinated layer farms

    PubMed Central

    Khorajiya, J. H.; Pandey, Sunanda; Ghodasara, Priya D.; Joshi, B. P.; Prajapati, K. S.; Ghodasara, D. J.; Mathakiya, R. A.

    2015-01-01

    Aim: The present research work was carried out to study the patho-epidemiological aspects of Genotype-XIII Newcastle disease virus (NDV) infection in commercial layer in and around Anand, Gujarat. As the outbreaks have reported in vaccinated flocks, it was felt necessary to study the disease with respect to its changing pathogenicity and relevant aspects. Materials and Methods: The study comprised of patho-epidemiology of Newcastle disease (ND) by information collected from different layer farms suffering from the disease in relation to incidence pattern and mortality, duration of mortality, susceptible age, and loss due to production performance. Clinical signs were recorded based on observations. During post-mortem, gross lesions were also recorded. For histopathological examination visceral organs according to lesions were collected in 10% formalin and processed slide stained by hematoxylin and eosin for microscopic examination. Cultivation of virus was done in embryonated specific pathogen-free (SPF) eggs of 9-11 days and isolation of virus was done for haemagglutination (HA) and haemagglutination inhibition (HI) test and to identify pathotype of virus by intracerebral pathogenicity index (ICPI) test to determine the virulence of virus. The Genotype-XIII NDV was confirmed by F gene sequence and whole genome sequence. Results: During the study mortality due to ND was recorded in 13 layer flocks in spite of routine vaccination, which usually contain Genotype-II strain of virus. The mortality was observed as high as above 50% with an average of 21.21%. The susceptible age for disease was found to be 6-14 weeks. The duration of mortality observed was 23 days. The disease resulted in a significant reduction in body weight, feed intake and drop in egg production. Majority of the outbreaks appeared during extremely hot months of April to June. Greenish diarrhoea was frequently seen in birds that survived early in infection. Mortality continued for 2-3 weeks and

  13. Effect of targeted mutation in collagen V alpha 2 gene on development of cutaneous hyperplasia in tight skin mice.

    PubMed Central

    Phelps, R. G.; Murai, C.; Saito, S.; Hatakeyama, A.; Andrikopoulos, K.; Kasturi, K. N.; Bona, C. A.

    1998-01-01

    Collagen V plays a major regulatory role in the formation of heterotypic fibers of the dermis and cartilaginous tissues as well as in the assembly of extracellular matrix. The pN/pN mouse, which is defective in collagen V alpha 2 gene, exhibits skeletal abnormalities, skin fragility, and alterations in the collagen fiber organization, whereas the TSK/+ mouse, which is defective in fibrillin-1, the major component of microfibrils present in the extracellular matrix, develops cutaneous hyperplasia and autoimmunity. We have studied the role of collagen V in the formation of heterotypic collagen fibers in F1 mice, which are obtained by breeding pN/pN with TSK/+ mice. Our results show that F1 progeny neither develop cutaneous hyperplasia nor produce anti-topoisomerase I autoantibodies, unlike TSK/+ mice. The diameter of the collagen fibrils in the skin is also comparable to that found in control mice. Thus, the phenotypic changes observed in the TSK mouse could be reversed by genetic complementation with a collagen V-defective mouse. Images Fig. 1 Fig. 2 Fig. 3 PMID:9642685

  14. Cleavage of Type I Collagen by Fibroblast Activation Protein-α Enhances Class A Scavenger Receptor Mediated Macrophage Adhesion

    PubMed Central

    Mazur, Anna; Holthoff, Emily; Vadali, Shanthi; Kelly, Thomas; Post, Steven R.

    2016-01-01

    Pathophysiological conditions such as fibrosis, inflammation, and tumor progression are associated with modification of the extracellular matrix (ECM). These modifications create ligands that differentially interact with cells to promote responses that drive pathological processes. Within the tumor stroma, fibroblasts are activated and increase the expression of type I collagen. In addition, activated fibroblasts specifically express fibroblast activation protein-α (FAP), a post-prolyl peptidase. Although FAP reportedly cleaves type I collagen and contributes to tumor progression, the specific pathophysiologic role of FAP is not clear. In this study, the possibility that FAP-mediated cleavage of type I collagen modulates macrophage interaction with collagen was examined using macrophage adhesion assays. Our results demonstrate that FAP selectively cleaves type I collagen resulting in increased macrophage adhesion. Increased macrophage adhesion to FAP-cleaved collagen was not affected by inhibiting integrin-mediated interactions, but was abolished in macrophages lacking the class A scavenger receptor (SR-A/CD204). Further, SR-A expressing macrophages localize with activated fibroblasts in breast tumors of MMTV-PyMT mice. Together, these results demonstrate that FAP-cleaved collagen is a substrate for SR-A-dependent macrophage adhesion, and suggest that by modifying the ECM, FAP plays a novel role in mediating communication between activated fibroblasts and macrophages. PMID:26934296

  15. MMP Regulation of Corneal Keratocyte Motility and Mechanics in 3-D Collagen Matrices

    PubMed Central

    Zhou, Chengxin; Petroll, W. Matthew

    2014-01-01

    outcome measures, the inhibitory effect of BB-94 was significantly greater than that of GM6001. Overall, the data demonstrate for the first time that even under conditions in which low levels of contractility and extracellular matrix proteolysis are maintained, MMPs still play an important role in mediating cell spreading and migration within 3-D collagen matrices. This appears to be mediated at least in part by membrane-tethered MMPs, such as MT1-MMP. PMID:24530619

  16. Effects of baicalin on collagen Ι and collagen ΙΙΙ expression in pulmonary arteries of rats with hypoxic pulmonary hypertension

    PubMed Central

    LIU, PANPAN; YAN, SHUANGQUAN; CHEN, MAYUN; CHEN, ALI; YAO, DAN; XU, XIAOMEI; CAI, XUEDING; WANG, LIANGXING; HUANG, XIAOYING

    2015-01-01

    The synthesis and accumulation of collagen play an important role in the formation and progression of hypoxic pulmonary hypertension. Baicalin has been reported to prevent bleomycin-induced pulmonary fibrosis. However, the role of baicalin in the treatment of pulmonary hypertension remains unknown. A disintegrin and metalloprotease with thrombospondin type-1 motif (ADAMTS-1) is a secreted enzyme that acts on a wide variety of extracellular matrix (ECM) substrates associated with vascular diseases. In this study, we aimed to investigate the effects of baicalin on the synthesis of collagen I in rats with pulmonary hypertension induced by hypoxia and the changes in ADAMTS-1 expression. A total of 24 Sprague Dawley rats were randomly assigned to 3 groups as follows: the control group (C), the hypoxia group (H) and the hypoxia + baicalin group (B). The rats in groups H and B were kept in a normobaric hypoxic chamber for 4 weeks, and the rats in group C were exposed to room air. We measured the hemodynamic indexes, including mean pulmonary artery pressure (mPAP), mean systemic (carotid) artery pressure (mSAP), and then calculated the mass ratio of right ventricle to left ventricle plus septum [RV/(LV + S)] to reflect the extent of right ventricular hypertrophy. We measured the mRNA and protein expression levels of type I collagen, type III collagen and ADAMTS-1 by hybridization in situ, and immunohistochemistry and western blot analysis, respectively. The results revealed that treatment with baicalin significantly reduced pulmonary artery pressure and attenuated the remodeling of the pulmonary artery under hypoxic conditions by increasing the expression of ADAMTS-1, so that the synthesis of type I collagen and its mRNA expression were inhibited. In conclusion, baicalin effectively inhibits the synthesis of collagen I in pulmonary arteries and this is associated with an increase in the expression of ADAMTS-1. Thus, treatment with baicalin may be an effective method for

  17. Investigation on interaction of tannic acid with type I collagen and its effect on thermal, enzymatic, and conformational stability for tissue engineering applications.

    PubMed

    Velmurugan, Punitha; Singam, Ettayapuram Ramaprasad Azhagiya; Jonnalagadda, Raghava Rao; Subramanian, Venkatesan

    2014-05-01

    Collagen is an essential component of tissues, which is the most abundant component in extracellular matrix and highly conserved across the animal kingdom. It can assemble into fiber and play an essential role in cell adhesion and growth and could be extremely useful in tissue engineering. In this study, the effect of tannic acid (TA) on the thermal, enzymatic and conformational stability of type I collagen has been investigated for the development of collagen-based biomaterials. Interaction of TA with collagen demonstrates the role of hydrogen bonding and hydrophobic interaction in providing the thermal and enzymatic stability. Thermal analysis studies reveal that, hydrothermal stability of collagen increases as well as inhibits the breakdown of collagenase by formation of hydrogen bonds and hydrophobic interactions. TA binds to the collagen with high affinity because the structural flexibility of the collagen compensates for the structural rigidity of the phenolics. Increase in concentration of TA induces significant change in the conformation of triple helix. The free binding energy of TA with collagen-like peptide was determined to be in the range of -9.4 to -11.2 kcal mol(-1), which was calculated by using Autodock Vina software and showed numerous hydrophobic and hydrogen bond interactions. We anticipate that these collagen-based biomaterials hold great potential for biomedical applications. PMID:23996786

  18. PREFACE: XIII International Conference on Calorimetry in High Energy Physics (CALOR 2008)

    NASA Astrophysics Data System (ADS)

    Livan, Michele

    2009-07-01

    The XIII International Conference on Calorimetry in High Energy Physics was held in Pavia, Italy, 26-30 May 2008, picking up the baton from the 2006 Conference in Chicago. The Conference took place in the unique environment of the Theresian Room of the University Library. The attendees were surrounded by over 40 000 books of general interest and culture, and had the opportunity to see precious volumes written by such people as Galileo, Volta and Faraday. The Workshop brought together more than 120 participants, including senior scientists as well as young physicists, confirming the central and ever-growing role of calorimeters in modern particle physics. The development of these detectors, as stressed by Professor Klaus Pretzl in his lectio magistralis, has made it possible to explore new frontiers in physics, and the present scenario is no exception to this rule. With the LHC experiments almost completely installed and ready to take data, the Conference was an ideal chance to review the status of the different projects, whose development has been followed and discussed throughout the entire Calor series, and to show that they are capable of meeting the design specifications. Other highlights were the performance and physics results of calorimeters installed in currently operating experiments. In the session on astrophysics and neutrinos, the contributions confirmed the key role of calorimeters in this sector and demonstrated their growing application even beyond the field of accelerator physics. Considerable time was devoted to the state-of-the-art techniques in the design and operation of the detectors, while the session on simulation addressed the importance of a thorough understanding of the shower development to meet the demanding requirements of present experiments. Finally, on the R&D side, the particle flow and dual read-out concepts confronted the challenges issued by the next generation of experiments. This complex material was reviewed in 83

  19. Evaluation of collagen in atherosclerotic plaques: the use of two coherent laser-based imaging methods

    PubMed Central

    Nadkarni, Seemantini K.; Bouma, Brett E.; de Boer, Johannes; Tearney, Guillermo J.

    2009-01-01

    Acute coronary events such as myocardial infarction are frequently caused by the rupture of unstable atherosclerotic plaque. Collagen plays a key role in determining plaque stability. Methods to measure plaque collagen content are invaluable in detecting unstable atherosclerotic plaques. Recently, novel coherent laser-based imaging techniques, such as polarization-sensitive optical coherence tomography (PSOCT) and laser speckle imaging (LSI) have been investigated, and they provide a wealth of information related to collagen content and plaque stability. Additionally, given their potential for intravascular use, these technologies will be invaluable for improving our understanding of the natural history of plaque development and rupture and, hence, enable the detection of unstable plaques. In this article we review recent developments in these techniques and potential challenges in translating these methods into intra-arterial use in patients. PMID:18386093

  20. The Scottish Play.

    ERIC Educational Resources Information Center

    Wheat, Chris

    1999-01-01

    Recounts an episode when, as young schoolboys, Prince Charles and classmates presented "Macbeth" as an end-of-term-play. Traces the events at school that took on different meanings when viewed from maturity. (NH)

  1. The School Play

    ERIC Educational Resources Information Center

    Lathan, P. D.

    1977-01-01

    Offers a defense of the school play as a vastly underrated educational tool. Available from: Speech and Drama, Elizabeth Gradwell, Distribution Manager, The White Cottage, Allington, Chippenham, Wilts. (MH)

  2. Play Spaces in Denmark.

    ERIC Educational Resources Information Center

    Mitchell, Edna; Anderson, Robert T.

    1980-01-01

    Describes the variety of play spaces found in urban areas in Denmark: in banks, stores and individual businesses, neighborhood parks and small pocket playgrounds, specialized adventure and traffic playgrounds with supervised activities, and commercial amusement parks. (CM)

  3. Effects of soybean peptide and collagen peptide on collagen synthesis in normal human dermal fibroblasts.

    PubMed

    Tokudome, Yoshihiro; Nakamura, Kyosuke; Kage, Madoka; Todo, Hiroaki; Sugibayashi, Kenji; Hashimoto, Fumie

    2012-09-01

    The collagen present in the dermis of the skin is a fibrous protein that fills the gaps between cells and helps maintain tissue flexibility. Effectively increasing the collagen present in the skin is an important goal for cosmetic research. Recent research has shown that soybean peptide (SP) has anti-fatigue activity, antioxidant activity, and the ability to increase type I collagen, while collagen peptide (CP) has the ability to enhance corneal moisture content and viscoelasticity, as well as to increase levels of hyaluronic acid synthesizing enzymes in human skin. Little documented research, however, has been conducted on collagen formation in relation to these peptides. Therefore, this research applied SP and CP with molecular weights primarily around 500 and preparations containing both SP and CP to normal human dermal fibroblasts together with magnesium ascorbyl phosphate (VC-PMg), and used real-time PCR to determine the gene expression of type I collagen (COL1A1), which contributes to collagen synthesis, and Smad7, which contribute to collagen breakdown. In addition, enzyme linked immuno sorbent assay (ELISA) was used to measure collagen content in the media. COL1A1 gene expression at 24 h after sample addition showed higher tendency in all samples and increased with time at 4, 8 and 24 h after addition. Smad7 gene expression was not substantially different at 4 h after addition. matrix metalloproteinase-1 gene expression was higher following SP addition, but was lower after the addition of CP and SP+CP. Medium collagen content was higher in all samples and increased with time at 8 h after addition. Collagen levels were higher when SP and CP were added together. PMID:22264122

  4. A mouse 3T6 fibroblast cell culture model for the study of normal and protein-engineered collagen synthesis and deposition into the extracellular matrix.

    PubMed

    Lamandé, S R; Bateman, J F

    1993-07-01

    Mouse 3T6 fibroblasts deposited an organized collagenous extracellular matrix during long-term culture in the presence of ascorbic acid. The matrix produced by the cells had a similar distribution of collagen types as the mouse dermal matrix, comprising predominantly type I with smaller amounts of types III and V collagens. By day 8 of culture more than 70% of the collagen in the 3T6 matrix was involved in covalent crosslinkages and required pepsin digestion for extraction. Incorporation of NaB3H4 into reducible crosslinks and aldehydes directly demonstrated the involvement of the alpha 1 (I)CB6 and alpha 2(I)CB3.5 in crosslinks. The pattern of reducible crosslinks in the in vitro 3T6 matrix was similar to that in mouse skin suggesting a comparable fibril organization. Processing of procollagen to collagen occurred efficiently throughout the culture period and the rate of collagen production was unaltered during 15 days of culture, indicating that the development of a collagenous matrix does not directly play a role in procollagen processing or biosynthetic regulation. The existence of a preformed matrix did however, increase the efficiency with which newly synthesised collagen was incorporated into the pericellular matrix. At day 0, when there was no measurable matrix present, 29% of the collagen synthesised was deposited, while by day 15, 88% of the collagen was laid down in the matrix. The development of this 3T6 culture system, where collagen is efficiently incorporated into an organized extracellular matrix, will facilitate detailed studies on matrix organization and regulation and provide a system in which protein-engineered mutant collagens can be expressed to determine their effects on the production of a functional extracellular matrix. PMID:8412990

  5. Collagen VI regulates satellite cell self-renewal and muscle regeneration

    PubMed Central

    Urciuolo, Anna; Quarta, Marco; Morbidoni, Valeria; Gattazzo, Francesca; Molon, Sibilla; Grumati, Paolo; Montemurro, Francesca; Tedesco, Francesco Saverio; Blaauw, Bert; Cossu, Giulio; Vozzi, Giovanni; Rando, Thomas A.; Bonaldo, Paolo

    2013-01-01

    Adult muscle stem cells, or satellite cells play essential roles in homeostasis and regeneration of skeletal muscles. Satellite cells are located within a niche that includes myofibers and extracellular matrix. The function of specific extracellular matrix molecules in regulating SCs is poorly understood. Here we show that the extracellular matrix protein collagen VI is a key component of the satellite cell niche. Lack of collagen VI in Col6a1−/− mice causes impaired muscle regeneration and reduced satellite cell self-renewal capability after injury. Collagen VI null muscles display significant decrease of stiffness, which is able to compromise the in vitro and in vivo activity of wild-type satellite cells. When collagen VI is reinstated in vivo by grafting wild-type fibroblasts, the biomechanical properties of Col6a1−/− muscles are ameliorated and satellite cell defects rescued. Our findings establish a critical role for an extracellular matrix molecule in satellite cell self-renewal and open new venues for therapies of collagen VI-related muscle diseases. PMID:23743995

  6. A comparative study of skin cell activities in collagen and fibrin constructs.

    PubMed

    Law, Jia Xian; Musa, Faiza; Ruszymah, Bt Hj Idrus; El Haj, Alicia J; Yang, Ying

    2016-09-01

    Collagen and fibrin are widely used in tissue engineering due to their excellent biocompatibility and bioactivities that support in vivo tissue formation. These two hydrogels naturally present in different wound healing stages with different regulatory effects on cells, and both of them are mechanically weak in the reconstructed hydrogels. We conducted a comparative study by the growth of rat dermal fibroblasts or dermal fibroblasts and epidermal keratinocytes together in collagen and fibrin constructs respectively with and without the reinforcement of electrospun poly(lactic acid) nanofiber mesh. Cell proliferation, gel contraction and elastic modulus of the constructs were measured on the same gels at multiple time points during the 22 day culturing period using multiple non-destructive techniques. The results demonstrated considerably different cellular activities within the two types of constructs. Co-culturing keratinocytes with fibroblasts in the collagen constructs reduced the fibroblast proliferation, collagen contraction and mechanical strength at late culture point regardless of the presence of nanofibers. Co-culturing keratinocytes with fibroblasts in the fibrin constructs promoted fibroblast proliferation but exerted no influence on fibrin contraction and mechanical strength. The presence of nanofibers in the collagen and fibrin constructs played a favorable role on the fibroblast proliferation when keratinocytes were absent. Thus, this study exhibited new evidence of the strong cross-talk between keratinocytes and fibroblasts, which can be used to control fibroblast proliferation and construct contraction. This cross-talk activity is extracellular matrix-dependent in terms of the fibrous network morphology, density and strength. PMID:27349492

  7. Configurational effects of collagen/ALP coatings on enzyme immobilization and surface mineralization

    NASA Astrophysics Data System (ADS)

    Bosco, R.; Leeuwenburgh, S. C. G.; Jansen, J. A.; van den Beucken, J. J. J. P.

    2014-08-01

    The ultimate goal for surface modifications in bone implants is to achieve biologically active surface able to control and trigger specific tissue response. In this study was evaluated the effects of organic compound, derived from extracellular matrix, involved in tissue mineralization. Alkaline phosphatase (ALP) plays a fundamental role in bone mineralization concurrently with collagen, the main organic components of bones. Electrospray deposition (ESD) was used to coat titanium disks with ALP and collagen at room temperature. To verify the synergistic role of ALP and collagen different conformations of coatings (mixed and layered) were obtained and their mineralization capacity was tested in vitro. The mineralization tests indicated the fundamental role of collagen to increase ALP coating retention. Analyses indicated that the coating conformation has a role; in fact the mixed group showed improved ALP retention, enzymatic activity and unique mineralized surface morphology. ESD demonstrated to be a successful method to deposit organic molecules preserving their properties as indicated by the in vitro results. These findings proved the synergistic effect of ALP and collagen in inducing mineralization offering an intriguing coating constituent for medical device that aim to trigger surface mineralization such as bone implants.

  8. Retinoic acid modulates rat Ito cell proliferation, collagen, and transforming growth factor beta production.

    PubMed Central

    Davis, B H; Kramer, R T; Davidson, N O

    1990-01-01

    Recent studies suggest that vitamin A plays an inhibitory role with respect to "activation" of the hepatic Ito cell, a likely effector of hepatic fibrogenesis. Ito cell "activation" during fibrogenesis is characterized by a decrease in intracellular vitamin A and an increase in cellular proliferation and collagen production. To explore the hypothesis that retinoids have the capacity to diminish Ito cell activation, cultured Ito cells were exposed to retinoic acid and its effects assessed on three key features: cell proliferation, collagen protein production and mRNA abundance, and transforming growth factor beta protein production. Retinoic acid was 100-1,000X more potent than retinol with respect to inhibition of Ito cell proliferation. Interstitial collagen and transforming growth factor beta production were also reduced by 10(-6) M retinoic acid. The relative abundance of type I collagen mRNA however, was not significantly altered. By contrast, retinoic acid administration to rats caused a marked reduction in the abundance of type I collagen mRNA in both total hepatic and purified Ito cell RNA. The relative abundance of rat hepatic fibronectin or apolipoprotein E mRNA was not significantly altered. These studies demonstrate that retinoic acid can differentially modulate several key features of hepatic fibrogenesis in vitro and in vivo. Images PMID:2254460

  9. Dynamic behaviors of astrocytes in chemically modified fibrin and collagen hydrogels.

    PubMed

    Seyedhassantehrani, Negar; Li, Yongchao; Yao, Li

    2016-05-16

    Astrocytes play a critical role in supporting the normal physiological function of neurons in the central nervous system (CNS). Astrocyte transplantation can potentially promote axonal regeneration and functional recovery after spinal cord injury (SCI). Fibrin and collagen hydrogels provide growth-permissive substrates and serve as carriers for therapeutic cell transplantation into an injured spinal cord. However, the application of fibrin and collagen hydrogels may be limited due to their relatively rapid degradation rate in vivo. In this study, immature astrocytes isolated from neonatal rats were grown in fibrin hydrogels containing aprotinin and collagen hydrogels crosslinked with poly(ethylene glycol) ether tetrasuccinimidyl glutarate (4S-StarPEG), and the cell behavior in these hydrogels was studied. The cell viability of astrocytes in the hydrogels was tested using the LIVE/DEAD® assay and the AlamarBlue® assay, and this study showed that astrocytes maintained good viability in these hydrogels. The cell migration study showed that astrocytes migrated in the fibrin and collagen hydrogels, and the migration speed is similar in these hydrogels. The crosslinking of collagen hydrogels with 4S-StarPEG did not change the astrocyte migration speed. However, the addition of aprotinin in the fibrin hydrogel inhibited astrocyte migration. The expression of chondroitin sulfate proteoglycan (CSPG), including NG2, neurocan, and versican, by astrocytes grown in the hydrogels was analyzed by quantitative RT-PCR. The expression of NG2, neurocan, and versican by the cells in these hydrogels was not significantly different. PMID:27079938

  10. Collagen V Is a Potential Substrate for Clostridial Collagenase G in Pancreatic Islet Isolation

    PubMed Central

    Shima, Hiroki; Inagaki, Akiko; Imura, Takehiro; Yamagata, Youhei; Watanabe, Kimiko; Igarashi, Kazuhiko; Goto, Masafumi; Murayama, Kazutaka

    2016-01-01

    The clostridial collagenases, H and G, play key roles in pancreatic islet isolation. Collagenases digest the peptide bond between Yaa and the subsequent Gly in Gly-Xaa-Yaa repeats. To fully understand the pancreatic islet isolation process, identification of the collagenase substrates in the tissue is very important. Although collagen types I and III were reported as possible substrates for collagenase H, the substrate for collagenase G remains unknown. In this study, collagen type V was focused upon as the target for collagenases. In vitro digestion experiments for collagen type V were performed and analyzed by SDS-PAGE and mass spectrometry. Porcine pancreatic tissues were digested in vitro under three conditions and observed during digestion. The results revealed that collagen type V was only digested by collagenase G and that the digestion was initiated from the N-terminal part. Tissue degradation during porcine islet isolation was only observed in the presence of both collagenases H and G. These findings suggest that collagen type V is one of the substrates for collagenase G. The enzymatic activity of collagenase G appears to be more important for pancreatic islet isolation in large mammals such as pigs and humans. PMID:27195301

  11. Endothelial monolayers on collagen-coated nanofibrous membranes: cell-cell and cell-ECM interactions.

    PubMed

    Kang, Donggu; Kim, Jeong Hwa; Jeong, Young Hun; Kwak, Jong-Young; Yoon, Sik; Jin, Songwan

    2016-06-01

    Endothelial cells (ECs) form a monolayer lining over the entire vascular wall and play an important role in maintaining vascular homeostasis and cancer metastasis. Loss of proper endothelial function can lead to vascular diseases. Therefore, the endothelial monolayer is particularly important in tissue regeneration and mimicking vascular tissue in vitro. Numerous studies have described the effects of ECs on nanofibers made from a variety of synthetic polymer materials designed to mimic the extracellular matrix (ECM). However, little is known about maintaining the integrity of ECs in in vitro systems. Here we describe polycaprolactone nanofibrous membranes coated with collagen gel that overcome many limitations of conventional nanofibers used for engineering endothelia. We investigated cell-cell and cell-ECM junctional complexes using collagen-coated and conventional nanofibrous membranes. Conventional nanofibrous membranes alone did not form a monolayer with ECs, whereas collagen-coated nanofibrous membranes did. Several concentrations of collagen in the gel coating promoted the formation of cell-cell junctional complexes, facilitated the deposition of laminin, and increased the focal contact organization of ECs. These results suggest the possible use of collagen-coated nanofibrous membranes for vascular tissue engineering applications and a vascular platform for organ-on-a-chip systems. PMID:27186924

  12. Characterization of Fibrin and Collagen Gels for Engineering Wound Healing Models

    PubMed Central

    Moreno-Arotzena, Oihana; Meier, Johann G.; del Amo, Cristina; García-Aznar, José Manuel

    2015-01-01

    Hydrogels are used for 3D in vitro assays and tissue engineering and regeneration purposes. For a thorough interpretation of this technology, an integral biomechanical characterization of the materials is required. In this work, we characterize the mechanical and functional behavior of two specific hydrogels that play critical roles in wound healing, collagen and fibrin. A coherent and complementary characterization was performed using a generalized and standard composition of each hydrogel and a combination of techniques. Microstructural analysis was performed by scanning electron microscopy and confocal reflection imaging. Permeability was measured using a microfluidic-based experimental set-up, and mechanical responses were analyzed by rheology. We measured a pore size of 2.84 and 1.69 μm for collagen and fibrin, respectively. Correspondingly, the permeability of the gels was 1.00·10−12 and 5.73·10−13 m2. The shear modulus in the linear viscoelastic regime was 15 Pa for collagen and 300 Pa for fibrin. The gels exhibited strain-hardening behavior at ca. 10% and 50% strain for fibrin and collagen, respectively. This consistent biomechanical characterization provides a detailed and robust starting point for different 3D in vitro bioapplications, such as collagen and/or fibrin gels. These features may have major implications for 3D cellular behavior by inducing divergent microenvironmental cues. PMID:26290683

  13. Diabetes alters mechanical properties and collagen fiber re-alignment in multiple mouse tendons.

    PubMed

    Connizzo, Brianne K; Bhatt, Pankti R; Liechty, Kenneth W; Soslowsky, Louis J

    2014-09-01

    Tendons function to transfer load from muscle to bone through their complex composition and hierarchical structure, consisting mainly of type I collagen. Recent evidence suggests that type II diabetes may cause alterations in collagen structure, such as irregular fibril morphology and density, which could play a role in the mechanical function of tendons. Using the db/db mouse model of type II diabetes, the diabetic skin was found to have impaired biomechanical properties when compared to the non-diabetic group. The purpose of this study was to assess the effect of diabetes on biomechanics, collagen fiber re-alignment, and biochemistry in three functionally different tendons (Achilles, supraspinatus, patellar) using the db/db mouse model. Results showed that cross-sectional area and stiffness, but not modulus, were significantly reduced in all three tendons. However, the tendon response to load (transition strain, collagen fiber re-alignment) occurred earlier in the mechanical test, contrary to expectations. In addition, the patellar tendon had an altered response to diabetes when compared to the other two tendons, with no changes in fiber re-alignment and decreased collagen content at the midsubstance of the tendon. Overall, type II diabetes alters tendon mechanical properties and the dynamic response to load. PMID:24833253

  14. Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

    PubMed Central

    Connizzo, Brianne K.; Bhatt, Pankti R.; Liechty, Kenneth W.; Soslowsky, Louis J.

    2014-01-01

    Tendons function to transfer load from muscle to bone through their complex composition and hierarchical structure, consisting mainly of type I collagen. Recent evidence suggests that type II diabetes may cause alterations in collagen structure, such as irregular fibril morphology and density, which could play a role in the mechanical function of tendons. Using the db/db mouse model of type II diabetes, the diabetic skin was found to have impaired biomechanical properties when compared to the non-diabetic group. The purpose of this study was to assess the effect of diabetes on biomechanics, collagen fiber re-alignment, and biochemistry in three functionally different tendons (Achilles, supraspinatus, patellar) using the db/db mouse model. Results showed that cross-sectional area and stiffness, but not modulus, were significantly reduced in all three tendons. However, the tendon response to load (transition strain, collagen fiber re-alignment) occurred earlier in the mechanical test, contrary to expectations. In addition, the patellar tendon had an altered response to diabetes when compared to the other two tendons, with no changes in fiber realignment and decreased collagen content at the midsubstance of the tendon. Overall, type II diabetes alters tendon mechanical properties and the dynamic response to load. PMID:24833253

  15. Effects of Panax ginseng extract on human dermal fibroblast proliferation and collagen synthesis.

    PubMed

    Lee, Geum-Young; Park, Kang-Gyun; Namgoong, Sik; Han, Seung-Kyu; Jeong, Seong-Ho; Dhong, Eun-Sang; Kim, Woo-Kyung

    2016-03-01

    Current studies of Panax ginseng (or Korean ginseng) have demonstrated that it has various biological effects, including angiogenesis, immunostimulation, antimicrobial and anti-inflammatory effects. Therefore, we hypothesised that P. ginseng may also play an important role in wound healing. However, few studies have been conducted on the wound-healing effects of P. ginseng. Thus, the purpose of this in vitro pilot study was to determine the effects of P. ginseng on the activities of fibroblasts, which are key wound-healing cells. Cultured human dermal fibroblasts were treated with one of six concentrations of P. ginseng: 0, 1, 10 and 100 ng/ml and 1 and 10 µg/ml. Cell proliferation was determined 3 days post-treatment using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay, and collagen synthesis was evaluated by the collagen type I carboxy-terminal propeptide method. Cell proliferation levels and collagen synthesis were compared among the groups. The 10 ng/ml to 1 µg/ml P. ginseng treatments significantly increased cell proliferation, and the 1 ng/ml to 1 µg/ml concentrations significantly increased collagen synthesis. The maximum effects for both parameters were observed at 10 ng/ml. P. ginseng stimulated human dermal fibroblast proliferation and collagen synthesis at an optimal concentration of 10 ng/ml. PMID:26507878

  16. Decreased type V collagen expression in human decidual tissues of spontaneous abortion during early pregnancy.

    PubMed Central

    Iwahashi, M; Nakano, R

    1998-01-01

    AIM: To provide some insight into the aetiology of spontaneous abortion, the contents of type V collagen was investigated in human decidual tissues in spontaneous abortion and normal pregnancy. METHODS: Collagens were extracted from decidual tissues in spontaneous abortion (n = 19) and normal pregnancy (n = 25). The different types of collagen alpha chains were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), stained with Coomassie brilliant blue, and measured by densitometry. The relative amounts of the alpha 1 (III) and alpha 1 (V) chains were calculated by dividing the band intensities of the alpha 1 (III) and alpha 1 (V) chains by that of the alpha 1 (I) chain. RESULTS: The ratio of the alpha 1 (V) chain to that of the alpha 1 (I) chain in decidual tissues in spontaneous abortion was significantly lower than that found in normal pregnancy (p < 0.05). CONCLUSIONS: These results suggest that type V collagen might play an important role in the maintenance of pregnancy and that decreased expression of this collagen could be associated with spontaneous abortion. Images PMID:9577371

  17. [Prevention and therapeutic effects of sika deer velvet collagen hydrolysate on osteoporosis in rats by retinoic acid].

    PubMed

    Li, Yinqing; Zhao, Yu; Sun, Xiaodi; Qu, Xiaobo

    2010-03-01

    The objective was to evaluate the preventive and therapeutic effects of the collagen hydrolysate extracted from Sika deer velvet (CSDV) on osteoporosis rats induced by retinoicacid. Histomorphometric indices and serum biochemical parameters were measured in osteoporosis rats treated with/without antler collagen and in sham-operated rats. Our results were as follows: compared with the osteoporosis group, significant elevation in the levels of bone mineral density (BMD), Ca, P and static histomorphometric indexes and biomechanical properties, but reduction in the level of serum alkaline phosphatase (ALP) were observed in antler collagen-treated groups. However, the above function with the collagenase solution velvet material varied with the different doses. In conclusion, the extracted collagen is found to play a role in the prevention and treatment of osteoporosis rats by retinoic acid. PMID:20545204

  18. Collagen type IV of Drosophila is stockpiled in the growing oocyte and differentially located during early stages of embryogenesis.

    PubMed

    Knibiehler, B; Mirre, C; Le Parco, Y

    1990-05-01

    We have developed and characterized a battery of specific polyclonal antibodies directed against specific portions of the alpha-chain of collagen type IV synthesized in Drosophila by the gene DCg1. Here, we describe the use of these antibodies together with in situ hybridization experiments in an attempt to study the expression and localization of collagen type IV during Drosophila oogenesis and early embryogenesis. The results clearly demonstrate that DCg1 is maternally expressed by follicle cells and that the collagen type IV chain produced is stockpiled in the growing oocyte. During the gastrulation stages, this component of Drosophila basement membranes concentrated on cells involved in the gradual invaginations leading to morphogenetic furrows. The presence of collagen type IV, which is an RGD-bearing molecule, during early stages of Drosophila development is discussed in comparison with the crucial, active role its vertebrate counterpart is supposed to play in morphogenetic processes. PMID:2117479

  19. Analysis of forward and backward Second Harmonic Generation images to probe the nanoscale structure of collagen within bone and cartilage.

    PubMed

    Houle, Marie-Andrée; Couture, Charles-André; Bancelin, Stéphane; Van der Kolk, Jarno; Auger, Etienne; Brown, Cameron; Popov, Konstantin; Ramunno, Lora; Légaré, François

    2015-11-01

    Collagen ultrastructure plays a central role in the function of a wide range of connective tissues. Studying collagen structure at the microscopic scale is therefore of considerable interest to understand the mechanisms of tissue pathologies. Here, we use second harmonic generation microscopy to characterize collagen structure within bone and articular cartilage in human knees. We analyze the intensity dependence on polarization and discuss the differences between Forward and Backward images in both tissues. Focusing on articular cartilage, we observe an increase in Forward/Backward ratio from the cartilage surface to the bone. Coupling these results to numerical simulations reveals the evolution of collagen fibril diameter and spatial organization as a function of depth within cartilage. PMID:26349534

  20. Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

    PubMed Central

    Li, Yang; Foss, Catherine A.; Pomper, Martin G.; Yu, S. Michael

    2014-01-01

    Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an integral part of normal tissue renewal, excessive amount of remodeling activity is involved in tumors, arthritis, and many other pathological conditions. During collagen remodeling, the triple helical structure of collagen molecules is disrupted by proteases in the extracellular environment. In addition, collagens present in many histological tissue samples are partially denatured by the fixation and preservation processes. Therefore, these denatured collagen strands can serve as effective targets for biological imaging. We previously developed a caged collagen mimetic peptide (CMP) that can be photo-triggered to hybridize with denatured collagen strands by forming triple helical structure, which is unique to collagens. The overall goals of this procedure are i) to image denatured collagen strands resulting from normal remodeling activities in vivo, and ii) to visualize collagens in ex vivo tissue sections using the photo-triggered caged CMPs. To achieve effective hybridization and successful in vivo and ex vivo imaging, fluorescently labeled caged CMPs are either photo-activated immediately before intravenous injection, or are directly activated on tissue sections. Normal skeletal collagen remolding in nude mice and collagens in prefixed mouse cornea tissue sections are imaged in this procedure. The imaging method based on the CMP-collagen hybridization technology presented here could lead to deeper understanding of the tissue remodeling process, as well as allow development of new diagnostics for diseases associated with high collagen remodeling activity. PMID:24513868

  1. Characterization of collagen gel solutions and collagen matrices for cell culture.

    PubMed

    Sheu, M T; Huang, J C; Yeh, G C; Ho, H O

    2001-07-01

    The influence of glutaraldehyde as a crosslinking agent to increase the strength of collagen matrices for cell culture was examined in this study. Collagen solutions of 1% were treated with different concentrations (0-0.2%) of glutaraldehyde for 24 h. The viscoelasticity of the resulting collagen gel solution was measured using dynamic mechanical analysis (DMA), which demonstrated that all collagen gel solutions examined followed the same model pattern. The creep compliance model of Voigt-Kelvin satisfactorily described the change of viscoelasticity expressed by these collagen gel solutions. These crosslinked collagen gel solutions were freeze-dried to form a matrix with a thickness of about 0.2-0.3 mm. The break modulus of these collagen matrices measured by DMA revealed that the higher the degree of crosslinking. the higher the break modulus. The compatibility of fibroblasts isolated from nude mouse skin with these collagen matrices was found to be acceptable at a cell density of 3 x 10(5) cells/cm2 with no contraction, even when using a concentration of glutaraldehyde of up to 0.2%. PMID:11396874

  2. A collagen-binding EGFR antibody fragment targeting tumors with a collagen-rich extracellular matrix

    PubMed Central

    Liang, Hui; Li, Xiaoran; Wang, Bin; Chen, Bing; Zhao, Yannan; Sun, Jie; Zhuang, Yan; Shi, Jiajia; Shen, He; Zhang, Zhijun; Dai, Jianwu

    2016-01-01

    Many tumors over-express collagen, which constitutes the physical scaffold of tumor microenvironment. Collagen has been considered to be a target for cancer therapy. The collagen-binding domain (CBD) is a short peptide, which could bind to collagen and achieve the sustained release of CBD-fused proteins in collagen scaffold. Here, a collagen-binding EGFR antibody fragment was designed and expressed for targeting the collagen-rich extracellular matrix in tumors. The antibody fragment (Fab) of cetuximab was fused with CBD (CBD-Fab) and expressed in Pichia pastoris. CBD-Fab maintained antigen binding and anti-tumor activity of cetuximab and obtained a collagen-binding ability in vitro. The results also showed CBD-Fab was mainly enriched in tumors and had longer retention time in tumors in A431 s.c. xenografts. Furthermore, CBD-Fab showed a similar therapeutic efficacy as cetuximab in A431 xenografts. Although CBD-Fab hasn’t showed better therapeutic effects than cetuximab, its smaller molecular and special target may be applicable as antibody–drug conjugates (ADC) or immunotoxins. PMID:26883295

  3. Plasma clot-promoting effect of collagen in relation to collagen-platelet interaction

    SciTech Connect

    Gentry, P.A.; Schneider, M.D.; Miller, J.K.

    1981-01-01

    The hemostatic function of several acid-soluble collagen preparations and a fibrillar-form collagen preparation have been compared. Pepsin-treated acid-soluble collagen isolated from burro and horse aortic tissue and acid-soluble colagen isolated from human umbilical cord readily promoted platelet aggregation, but failed to activate the coagulation mechanism even after prolonged incubation with plasma at 37 C. By contrast, fibrillar-form collagen isolated from burro aorta was both an efficient stimulant for the induction of platelet aggregation and a potent clot-promoting agent. Similar results were found for all the collagen preparations irrespective of whether the studies were conducted with sheep or with burro plasma. Heat denaturation studies showed that the hemostatic functon of the fibrillar-form colagen was dependent on an intact tirple-helical structure.

  4. Daily consumption of the collagen supplement Pure Gold Collagen® reduces visible signs of aging

    PubMed Central

    Borumand, Maryam; Sibilla, Sara

    2014-01-01

    With age, changes in the metabolic processes of structural components of the skin lead to visible signs of aging, such as increased dryness and wrinkle formation. The nutritional supplement, Pure Gold Collagen®, which consists of hydrolyzed collagen, hyaluronic acid, vitamins, and minerals, was developed to counteract these signs. An open-label study was conducted to investigate the effects of this nutritional supplement on skin properties. Supplementation with 50 mL of Pure Gold Collagen on a daily basis for 60 days led to a noticeable reduction in skin dryness, wrinkles, and nasolabial fold depth. In addition, a significant increase in collagen density and skin firmness was observed after 12 weeks. The data from this study suggest that Pure Gold Collagen can counteract signs of natural aging. PMID:25342893

  5. Lipoid proteinosis: an inherited disorder of collagen metabolism?

    PubMed

    Harper, J I; Duance, V C; Sims, T J; Light, N D

    1985-08-01

    The dermal collagen of a patient with lipoid proteinosis was investigated by immunohistochemistry and biochemical analysis. The affected skin was found to contain significantly less collagen per unit dry weight than normal dermis but showed elevated levels of type 3 collagen with respect to type I. Purification of collagen types from affected skin after pepsin digestion showed no novel forms, but a doubling in the yield of type 5 collagen. These results correlated well with those of immunohistochemistry which showed a patchy, diffuse, widely distributed type 3 collagen and an increase in types 4 and 5 collagens associated with 'onion skin' endothelial basement membrane thickening. Estimation of collagen cross-links showed an abnormal pattern with a preponderance of the keto-imine form not normally associated with skin. These results strongly suggest that lipoid proteinosis involves a primary perturbation of collagen metabolism. PMID:3896292

  6. Fluorescently labeled collagen binding proteins allow specific visualization of collagen in tissues and live cell culture.

    PubMed

    Krahn, Katy Nash; Bouten, Carlijn V C; van Tuijl, Sjoerd; van Zandvoort, Marc A M J; Merkx, Maarten

    2006-03-15

    Visualization of the formation and orientation of collagen fibers in tissue engineering experiments is crucial for understanding the factors that determine the mechanical properties of tissues. In this study, collagen-specific fluorescent probes were developed using a new approach that takes advantage of the inherent specificity of collagen binding protein domains present in bacterial adhesion proteins (CNA35) and integrins (GST-alpha1I). Both collagen binding domains were obtained as fusion proteins from an Escherichia coli expression system and fluorescently labeled using either amine-reactive succinimide (CNA35) or cysteine-reactive maleimide (GST-alpha1I) dyes. Solid-phase binding assays showed that both protein-based probes are much more specific than dichlorotriazinyl aminofluorescein (DTAF), a fluorescent dye that is currently used to track collagen formation in tissue engineering experiments. The CNA35 probe showed a higher affinity for human collagen type I than did the GST-alpha1I probe (apparent K(d) values of 0.5 and 50 microM, respectively) and showed very little cross-reactivity with noncollagenous extracellular matrix proteins. The CNA35 probe was also superior to both GST-alpha1I and DTAF in visualizing the formation of collagen fibers around live human venous saphena cells. Immunohistological experiments on rat tissue showed colocalization of the CNA35 probe with collagen type I and type III antibodies. The fluorescent probes described here have important advantages over existing methods for visualization of collagen, in particular for monitoring the formation of collagen in live tissue cultures over prolonged time periods. PMID:16476406

  7. New recommendations for measuring collagen solubility.

    PubMed

    Latorre, María E; Lifschitz, Adrian L; Purslow, Peter P

    2016-08-01

    The heat-solubility of intramuscular collagen is usually conducted in 1/4 Ringer's solution at pH7.4, despite this ionic strength and pH being inappropriate for post-rigor meat. The current work studied the percentage of soluble collagen and hydrothermal isometric tension characteristics of perimysial strips on bovine semitendinosus muscles in either 1/4 Ringer's solution, distilled water, PBS, or a solution of the same salt concentration as 1/4 Ringer's but at pH5.6. Values of % soluble collagen were lower at pH7.4 than 5.6. Increasing ionic strength reduced % soluble collagen. The maximum perimysial isometric tension was independent of the bathing medium, but the percent relaxation was higher at pH7.4 than at pH5.6, and increased with ionic strength of the media. It is recommended that future measurements of collagen solubility and tests on connective tissue components of post-rigor meat should be carried out in a solution of concentrations NaCl and KCl equivalent to those in 1/4 Ringer's, but at pH5.6, a pH relevant to post-rigor meat. PMID:27057755

  8. Collagenous colitis: new diagnostic possibilities with endomicroscopy

    NASA Astrophysics Data System (ADS)

    Hoffman, A.; Goetz, M.; Biesterfeld, S.; Galle, P. R.; Neurath, M. F.; Kiesslich, R.

    2006-02-01

    Collagenous colitis is a kind of microscopic colitis. It is characterized by chronic watery diarrhea and abdominal pain. The etiology is still unknown. So far, for the diagnose a histological evaluation was necessary with the presence of thickened subepithelial collagneous bands in the lamina propria. A new developed endoscope with a confocal laser allows analysing cellular and subcellular details of the mucosal layer at high resolution in vivo. In this case report we describe for the first time to diagnose collagenous colitis during ongoing colonoscopy by using this confocal endomicroscopy. In a 67 year old female patient with typical symptoms the characteristic histological changes could be identified in the endomicroscopic view. Biopsies could be targeted to affected areas and endomicroscopic prediction of the presence of collagenous bands could be confirmed in all targeted biopsies. First endomicroscopic experience in microscopic colitis could be confirmed in four additional patients. Future prospective studies are warranted to further evaluate these initial findings. However, collagenous colitis is frequently missed and endomicroscopy seems to be the ideal tool for accurate diagnosing collagenous colitis during ongoing endoscopy.

  9. Playing It Safe.

    ERIC Educational Resources Information Center

    O'Neill, Steve

    2000-01-01

    Provides tips on how to avoid accidents and injuries on school playgrounds. Tips include removing of old, dangerous equipment; relocating play areas to safer ground; choosing the right surface; factoring in long-term costs for replenishing and redistributing loose materials; and considering Americans with Disabilities Act issues. (GR)

  10. Predicting elections: child's play!

    PubMed

    Antonakis, John; Dalgas, Olaf

    2009-02-27

    In two experiments, children and adults rated pairs of faces from election races. Naïve adults judged a pair on competence; after playing a game, children chose who they would prefer to be captain of their boat. Children's (as well as adults') preferences accurately predicted actual election outcomes. PMID:19251621

  11. Want to Play Geometry?

    ERIC Educational Resources Information Center

    Kaufmann, Matthew L.; Bomer, Megan A.; Powell, Nancy Norem

    2009-01-01

    Students enter the geometry classroom with a strong concept of fairness and a sense of what it means to "play by the rules," yet many students have difficulty understanding the postulates, or rules, of geometry and their implications. Although they may never have articulated the properties of an axiomatic system, they have gained a practical…

  12. Statistics at Play

    ERIC Educational Resources Information Center

    English, Lyn D.

    2014-01-01

    An exciting event had occurred for the grade 3 classes at Woodlands State School. A new play space designated for the older grades had now been opened to the third graders. In sharing their excitement over this "real treat, real privilege," the teachers invited the children to find out more about playgrounds and, in particular, their new…

  13. "Playing" with Science

    ERIC Educational Resources Information Center

    Allen, Dave

    2012-01-01

    When faced with a multitude of tasks, any opportunity to "kill two birds with one stone" is welcome. Drama has always excited the author: as a child performing in plays, later as a student and now as a teacher directing performances and improvising within lessons. The author was lucky enough to have inspirational teachers during his primary and…

  14. Abstraction through Game Play

    ERIC Educational Resources Information Center

    Avraamidou, Antri; Monaghan, John; Walker, Aisha

    2012-01-01

    This paper examines the computer game play of an 11-year-old boy. In the course of building a virtual house he developed and used, without assistance, an artefact and an accompanying strategy to ensure that his house was symmetric. We argue that the creation and use of this artefact-strategy is a mathematical abstraction. The discussion…

  15. Who's Calling the Plays?

    ERIC Educational Resources Information Center

    Goldman, Jay P.

    1990-01-01

    Without an enforceable policy, school athletics programs are beset by politics, high finance, and public sentiment. The most nettlesome problems include loss of instructional time to sports and extracurricular activities; the appropriateness and effectiveness of no-pass/no-play rules; lack of sportsmanship; proliferation of interstate competition;…

  16. Playing with danger.

    PubMed

    Pearce, Lynne

    Young people who sit still for hours playing computer games can double their risk of potentially fatal blood clots. The charity Lifeblood is alerting nurses to 'e-thrombosis'. It is calling on them to ensure young people are aware of the risks of prolonged immobility and the need to take regular breaks from gaming or using a computer. PMID:23061127

  17. The Games Children Play

    ERIC Educational Resources Information Center

    Padak, Nancy; Rasinski, Timothy

    2008-01-01

    The games that children play are not just for fun-they often lead to important skill development. Likewise, word games are fun opportunities for parents and children to spend time together and for children to learn a lot about sounds and words. In this Family Involvement column, the authors describe 12 easy-to-implement word games that parents and…

  18. One Play a Day

    ERIC Educational Resources Information Center

    Blankenship, Mark

    2007-01-01

    Undergraduate theater students rarely get the chance to work on a major world premiere, but this year hundreds of them will. Currently, more than 70 colleges and universities are participating in "365 Days/365 Plays," an ambitious project from Pulitzer Prize-winning playwright Suzan-Lori Parks. Every week, as they mount their portion of this epic…

  19. Play's Importance in School

    ERIC Educational Resources Information Center

    Sandberg, Anette; Heden, Rebecca

    2011-01-01

    The purpose of this study is to contribute knowledge on and gain an understanding of elementary school teachers' perspectives on the function of play in children's learning processes. The study is qualitative with a hermeneutical approach and has George Herbert Mead as a theoretical frame of reference. Interviews have been carried out with seven…

  20. Playing It Safe.

    ERIC Educational Resources Information Center

    Jones, Rebecca

    1997-01-01

    Offers tips for avoiding sports-related injuries: (1) expect more of coaches; (2) develop an athletic-safety plan; (3) consider hiring an athletic trainer; (4) check facilities and equipment regularly; (5) recognize athletes' limitations; (6) take precautions beyond the playing field; and (7) check liability coverage and obtain informed consent.…

  1. Integrated Play Groups

    ERIC Educational Resources Information Center

    Glovak, Sandra

    2007-01-01

    As an occupational therapist running social play groups with sensory integration for children on the autism spectrum, the author frequently doubted the wisdom of combining several children on the spectrum into a group. In fact, as the owner of a clinic she said, "No more!" The groups seemed like a waste of parents' time and money, and she refused…

  2. Femtosecond laser collagen cross-linking without traditional photosensitizers

    NASA Astrophysics Data System (ADS)

    Guo, Yizang; Wang, Chao; Celi, Nicola; Vukelic, Sinisa

    2015-03-01

    Collagen cross-linking in cornea has the capability of enhancing its mechanical properties and thereby providing an alternative treatment for eye diseases such as keratoconus. Currently, riboflavin assisted UVA light irradiation is a method of choice for cross-link induction in eyes. However, ultrafast pulsed laser interactions may be a powerful alternative enabling in-depth treatment while simultaneously diminishing harmful side effects such as, keratocyte apoptosis. In this study, femtosecond laser is utilized for treatment of bovine cornea slices. It is hypothesized that nonlinear absorption of femtosecond laser pulses plays a major role in the maturation of immature cross-links and the promotion of their growth. Targeted irradiation with tightly focused laser pulses allows for the absence of a photosensitizing agent. Inflation test was conducted on half treated porcine cornea to identify the changes of mechanical properties due to laser treatment. Raman spectroscopy was utilized to study subtle changes in the chemical composition of treated cornea. The effects of treatment are analyzed by observing shifts in Amide I and Amide III bands, which suggest deformation of the collagen structure in cornea due to presence of newly formed cross-links.

  3. Biomimetic silicification of demineralized hierarchical collagenous tissues

    PubMed Central

    Ryou, Heonjune; Diogenes, Anibal; Yiu, Cynthia K.Y.; Mazzoni, Annalisa; Chen, Ji-hua; Arola, Dwayne D.; Hargreaves, Kenneth M.; Pashley, David H.; Tay, Franklin R.

    2013-01-01

    Unlike man-made composite materials, natural biominerals containing composites usually demonstrate different levels of sophisticated hierarchical structures which are responsible for their mechanical properties and other metabolic functions. However, the complex spatial organizations of the organic-inorganic phases are far beyond what they be achieved by contemporary engineering techniques. Here, we demonstrate that carbonated apatite present in collagen matrices derived from fish scale and bovine bone may be replaced by amorphous silica, using an approach that simulates what is utilized by phylogenetically ancient glass sponges. The structural hierarchy of these collagen-based biomaterials is replicated by the infiltration and condensation of fluidic polymer-stabilized silicic acid precursors within the intrafibrillar milieu of type I collagen fibrils. This facile biomimetic silicification strategy may be used for fabricating silica-based, three-dimensional functional materials with specific morphological and hierarchical requirements. PMID:23586938

  4. On the Collagen Mineralization. A Review

    PubMed Central

    TOMOAIA, GHEORGHE; PASCA, ROXANA-DIANA

    2015-01-01

    Collagen mineralization (CM) is a challenging process that has received a lot of attention in the past years. Among the reasons for this interest, the key role is the importance of collagen and hydroxyapatite in natural bone, as major constituents. Different protocols of mineralization have been developed, specially using simulated body fluid (SBF) and many methods have been used to characterize the systems obtained, starting with methods of determining the mineral content (XRD, FTIR, Raman, High-Resolution Spectral Ultrasound Imaging), continuing with imaging methods (AFM, TEM, SEM, Fluorescence Microscopy), thermal analysis (DSC and TGA), evaluation of the mechanical and biological properties, including statistical methods and molecular modeling. In spite of the great number of studies regarding collagen mineralization, its mechanism, both in vivo and in vitro, is not completely understood. Some of the methods used in vitro and investigation methods are reviewed here. PMID:26528042

  5. PREFACE: XIII International Conference on Calorimetry in High Energy Physics (CALOR 2008)

    NASA Astrophysics Data System (ADS)

    Livan, Michele

    2009-07-01

    The XIII International Conference on Calorimetry in High Energy Physics was held in Pavia, Italy, 26-30 May 2008, picking up the baton from the 2006 Conference in Chicago. The Conference took place in the unique environment of the Theresian Room of the University Library. The attendees were surrounded by over 40 000 books of general interest and culture, and had the opportunity to see precious volumes written by such people as Galileo, Volta and Faraday. The Workshop brought together more than 120 participants, including senior scientists as well as young physicists, confirming the central and ever-growing role of calorimeters in modern particle physics. The development of these detectors, as stressed by Professor Klaus Pretzl in his lectio magistralis, has made it possible to explore new frontiers in physics, and the present scenario is no exception to this rule. With the LHC experiments almost completely installed and ready to take data, the Conference was an ideal chance to review the status of the different projects, whose development has been followed and discussed throughout the entire Calor series, and to show that they are capable of meeting the design specifications. Other highlights were the performance and physics results of calorimeters installed in currently operating experiments. In the session on astrophysics and neutrinos, the contributions confirmed the key role of calorimeters in this sector and demonstrated their growing application even beyond the field of accelerator physics. Considerable time was devoted to the state-of-the-art techniques in the design and operation of the detectors, while the session on simulation addressed the importance of a thorough understanding of the shower development to meet the demanding requirements of present experiments. Finally, on the R&D side, the particle flow and dual read-out concepts confronted the challenges issued by the next generation of experiments. This complex material was reviewed in 83

  6. PREFACE: XIII International Seminar on Physics and Chemistry of Solids (ISPCS)

    NASA Astrophysics Data System (ADS)

    Berdowski, Janusz

    2007-06-01

    This volume of Journal of Physics: Conference Series contains some of the papers which were presented at the XIII International Seminar on Physics and Chemistry of Solids (ISPCS) in June 2007, in Ustroń, Poland. As the materials from ISPCS are presented in this Journal for the first time it is a good opportunity to give a brief outline of the Seminar's roots, history and goals. The initiator of the Seminars, conceived as annual meetings of the physicists and chemists from Ukraine and Poland, was the late Professor of the Ivan Franko National University in Lviv, Wlodymyr Sawicki. As Professor Sawicki had also lectured for the students of Jan Dlugosz University in Czȩstochowa he had seen both these universities as future organizers of the conference. Coincidentally rectors of Lviv and Czȩstochowa universities, Professor Ivan Vakarchuk and Professor Józef Światek were physicists so this proposition was received very warmly and got strong support from the officials of the universities. From the early beginnings the Seminar also had wide organizational help from the Research and Development Enterprise 'Carat' from Lviv and especially from its president Dr Mykola Vakiv. The Seminars started in 1996—the first meeting took place in Zakopane (Poland) in May 1996 and the second one in September of the same year in Schack (Ukraine). From 1997, ISPCS Seminars have gathered together a group of chemists and physicists interested in condensed matter physics and chemistry, in even years in Ukraine, in odd years in Poland. This circle is growing: at the first Seminar in Zakopane thirty scientists took part, mainly from Lviv and from Czȩstochowa, ISPCS13 gave us the opportunity to meet over eighty people from several universities and research institutions, including delegates from countries other than Poland and Ukraine, with over seventy presentations. The organizers plan that ISPCS conferences should achieve the following two objectives: help in building closer

  7. Subcellular localization of transglutaminase. Effect of collagen.

    PubMed Central

    Juprelle-Soret, M; Wattiaux-De Coninck, S; Wattiaux, R

    1988-01-01

    1. The subcellular distribution of transglutaminase was investigated by using the analytical approach of differential and isopycnic centrifugation as applied to three organs of the rat: liver, kidney and lung. After differential centrifugation by the method of de Duve, Pressman, Gianetto, Wattiaux & Appelmans [(1955) Biochem. J. 63, 604-617], transglutaminase is mostly recovered in the unsedimentable fraction S and the nuclear fraction N. After isopycnic centrifugation of the N fraction in a sucrose density gradient, a high proportion of the enzyme remains at the top of the gradient; a second but minor peak of activity is present in high-density regions, where a small proportion of 5'-nucleotidase, a plasma-membrane marker, is present together with a large proportion of collagen recovered in that fraction. 2. Fractions where a peak of transglutaminase was apparent in the sucrose gradient were examined by electron microscopy. The main components are large membrane sheets with extracellular matrix and free collagen fibers. 3. As these results seem to indicate that some correlation exists between particulate transglutaminase distribution and those of collagen and plasma membranes, the possible binding of transglutaminase by collagen (type I) and by purified rat liver plasma membrane was investigated. 4. The binding studies indicated that collagen is able to bind transglutaminase and to make complexes with plasma-membrane fragments whose density is higher than that of plasma-membrane fragments alone. Transglutaminase cannot be removed from such complexes by 1% Triton X-100, but can be to a relatively large extent by 0.5 M-KCl and by 50% (w/v) glycerol. 5. Such results suggest that the apparent association of transglutaminase with plasma membrane originates from binding in vitro of the cytosolic enzyme to plasma membrane bound to collagen, which takes place during homogenization of the tissue, when the soluble enzyme and extracellular components are brought together

  8. A rare case of cutaneous collagenous vasculopathy.

    PubMed

    Meah, Nekma; Khirwadkar, Nitin; Ellison, Judith

    2016-08-01

    Cutaneous collagenous vasculopathy is a rare microangiopathy first described by Salama and Rosenthal in 2000. Several cases have been reported to date, describing distinct histological findings of thick hyaline collagenous blood vessel walls in the superficial dermis. Clinical confusion can arise with generalised essential telangiectasia. We report a case occurring in a 76-year-old woman who presented with a 2-year history of a telangiectatic rash progressing from her knees upwards. The diagnosis was confirmed on skin biopsy and treatment with pulsed dye laser was later initiated at the patient's request. PMID:25872701

  9. Canada's east coast play

    SciTech Connect

    Doig, I.M.

    1984-02-01

    The intent of this paper is to give a basic overview presentation on Canada's east coast play - most likely the number one offshore play in the free world - and possibly the world. The play stretches 2,500 miles north and south, as it follows the Labrador Coast, past the Strait of Belle Isle and onto the Grand Banks of Newfoundland and as it makes a 90 degree turn, 1,000 miles east to west along the coast of Nova Scotia to the Georges Bank. 3,500 miles in all - which if placed in western Canada, would stretch from northern Alberta to southern Mexico. It's geologic potential is immense - 15-20 billion barrels of oil and 80-90 Tcf of natural gas. And so far only approximately 2 billion barrels of oil and 5 Tcf of natural gas have been found. There is more out there. And less than 200 wells have been drilled - still very virgin territory. Two world size discoveries have been made in the area. Hibernia, on the Grand Banks, is estimated to contain 1.8 billion barrels. Venture, on the Scotian Shelf, has a natural gas reserve of 2.5 Tcf - big by Canadian standards and significant in that Mobil Oil has also made some other interesting discoveries on the same Sable Island block which have not been delineated.

  10. Fully automated, quantitative, noninvasive assessment of collagen fiber content and organization in thick collagen gels

    NASA Astrophysics Data System (ADS)

    Bayan, Christopher; Levitt, Jonathan M.; Miller, Eric; Kaplan, David; Georgakoudi, Irene

    2009-05-01

    Collagen is the most prominent protein of human tissues. Its content and organization define to a large extent the mechanical properties of tissue as well as its function. Methods that have been used traditionally to visualize and analyze collagen are invasive, provide only qualitative or indirect information, and have limited use in studies that aim to understand the dynamic nature of collagen remodeling and its interactions with the surrounding cells and other matrix components. Second harmonic generation (SHG) imaging emerged as a promising noninvasive modality for providing high-resolution images of collagen fibers within thick specimens, such as tissues. In this article, we present a fully automated procedure to acquire quantitative information on the content, orientation, and organization of collagen fibers. We use this procedure to monitor the dynamic remodeling of collagen gels in the absence or presence of fibroblasts over periods of 12 or 14 days. We find that an adaptive thresholding and stretching approach provides great insight to the content of collagen fibers within SHG images without the need for user input. An additional feature-erosion and feature-dilation step is useful for preserving structure and noise removal in images with low signal. To quantitatively assess the orientation of collagen fibers, we extract the orientation index (OI), a parameter based on the power distribution of the spatial-frequency-averaged, two-dimensional Fourier transform of the SHG images. To measure the local organization of the collagen fibers, we access the Hough transform of small tiles of the image and compute the entropy distribution, which represents the probability of finding the direction of fibers along a dominant direction. Using these methods we observed that the presence and number of fibroblasts within the collagen gel significantly affects the remodeling of the collagen matrix. In the absence of fibroblasts, gels contract, especially during the first few

  11. The crucial role of collagen-binding integrins in maintaining the mechanical properties of human scleral fibroblasts-seeded collagen matrix

    PubMed Central

    Hu, Shoulong; Cui, Dongmei; Yang, Xiao; Hu, Jianmin; Wan, Wenjuan

    2011-01-01

    (p<0.01). However, the creep extension and creep rate of the integrin α2β1 antibody (1 μg/ml or 4 μg/ml) group were not significantly different from those in the integrin α1β1 antibody (1 μg/ml or 4 μg/ml) group (p>0.05). Conclusions Our findings suggested that HSF integrin α1β1 and α2β1 participated in maintaining the mechanical creep properties of the HSFs-seeded collagen matrix. Furthermore, integrin α2β1 might play a more crucial role in maintaining the mechanical creep properties of the collagen matrix than does integrin α1β1. PMID:21647271

  12. Intrafollicular collagenous crystalloids in a hair follicle of the nose.

    PubMed

    Kacerovska, Denisa; Michal, Michal; Kazakov, Dmitry V

    2011-12-01

    The authors report an unusual case of intrafollicular collagenous crystalloids in an 86-year-old woman. The presence of collagenous crystalloids within the follicular epithelium is intriguing and has not been described previously. PMID:19828595

  13. Fish collagen is an important panallergen in the Japanese population.

    PubMed

    Kobayashi, Y; Akiyama, H; Huge, J; Kubota, H; Chikazawa, S; Satoh, T; Miyake, T; Uhara, H; Okuyama, R; Nakagawara, R; Aihara, M; Hamada-Sato, N

    2016-05-01

    Collagen was identified as a fish allergen in early 2000s. Although its allergenic potential has been suggested to be low, risks associated with collagen as a fish allergen have not been evaluated to a greater extent. In this study, we aimed to clarify the importance of collagen as a fish allergen. Our results showed that 50% of Japanese patients with fish allergy had immunoglobulin E (IgE) against mackerel collagen, whereas 44% had IgE against mackerel parvalbumin. IgE inhibition assay revealed high cross-reactivity of mackerel collagen to 22 fish species (inhibition rates: 87-98%). Furthermore, a recently developed allergy test demonstrated that collagen triggered IgE cross-linking on mast cells. These data indicate that fish collagen is an important and very common panallergen in fish consumed in Japan. The high rate of individuals' collagen allergy may be attributable to the traditional Japanese custom of raw fish consumption. PMID:26785247

  14. Collagen cross-links as a determinant of bone quality: a possible explanation for bone fragility in aging, osteoporosis, and diabetes mellitus.

    PubMed

    Saito, M; Marumo, K

    2010-02-01

    Collagen cross-linking, a major post-translational modification of collagen, plays important roles in the biological and biomechanical features of bone. Collagen cross-links can be divided into lysyl hydroxylase and lysyloxidase-mediated enzymatic immature divalent cross-links,mature trivalent pyridinoline and pyrrole cross-links, and glycation- or oxidation-induced non-enzymatic cross-links(advanced glycation end products) such as glucosepane and pentosidine. These types of cross-links differ in the mechanism of formation and in function. Material properties of newly synthesized collagen matrix may differ in tissue maturity and senescence from older matrix in terms of crosslink formation. Additionally, newly synthesized matrix in osteoporotic patients or diabetic patients may not necessarily be as well-made as age-matched healthy subjects. Data have accumulated that collagen cross-link formation affects not only the mineralization process but also microdamage formation. Consequently, collagen cross-linking is thought to affect the mechanical properties of bone. Furthermore,recent basic and clinical investigations of collagen cross-links seem to face a new era. For instance, serum or urine pentosidine levels are now being used to estimate future fracture risk in osteoporosis and diabetes. In this review, we describe age-related changes in collagen cross-links in bone and abnormalities of cross-links in osteoporosis and diabetes that have been reported in the literature. PMID:19760059

  15. Do stress-whitening and optical clearing of collagenous tissue occur by the same mechanism?

    PubMed

    Hardisty, M R; Soicher, M A; Garcia, T C; Stover, S M; Fyhrie, D P

    2013-09-27

    Bone is biphasic with an organic matrix and an inorganic mineral component. As we age bone's susceptibility to fracture increases. It has been shown that there is no change in mean mineralization with aging, but bone nevertheless becomes less tough. This aging effect is therefore likely related to the organic phase. Under mechanical loading, immediately prior to failure, bone has been observed to visually become more opaque and has been termed stress-whitening. Stress-whitening is known to make materials tougher. The goal of this investigation was to investigate stress-whitening in the collagenous matrix of bone. Hydrogen bonds play a key role in collagen stability and we hypothesize that changes in hydrogen bonding will significantly affect matrix stiffness, toughness and stress whitening. Demineralized bone specimens were loaded in tension and stress-whitening was monitored. The effect of hydrogen bonding on mechanical properties and stress-whitening process was probed by altering the Hansen's hydrogen bonding parameter (δh) of the immersing solution. The Hansen's hydrogen bonding parameter of the immersing fluid affected the morphology, mechanical properties and stress whitening of specimens. Specimens were visually whiter in the absence of mechanical load in low δh solvents (the specimens solvent-whitened). Both the observed stress-whitening and solvent-whitening were reversible and repeatable processes. The observed solvent-whitening that occurred without the presence of load was consistent with solvent-induced optical clearing (the opposite of whitening) in skin caused by collagen fibril swelling. Stress whitening and solvent whitening can be explained by a common mechanism, collagen fibril densification and thinning, leading to an increased distinction between the collagen fibrillar phase and immersing fluid, ultimately leading to more scattering. Bones may be at a greater risk for fracture as we age because solubility of the matrix changes, thus making

  16. Contribution of collagen fiber undulation to regional biomechanical properties along porcine thoracic aorta.

    PubMed

    Zeinali-Davarani, Shahrokh; Wang, Yunjie; Chow, Ming-Jay; Turcotte, Raphaël; Zhang, Yanhang

    2015-05-01

    As major extracellular matrix components, elastin, and collagen play crucial roles in regulating the mechanical properties of the aortic wall and, thus, the normal cardiovascular function. The mechanical properties of aorta, known to vary with age and multitude of diseases as well as the proximity to the heart, have been attributed to the variations in the content and architecture of wall constituents. This study is focused on the role of layer-specific collagen undulation in the variation of mechanical properties along the porcine descending thoracic aorta. Planar biaxial tensile tests are performed to characterize the hyperelastic anisotropic mechanical behavior of tissues dissected from four locations along the thoracic aorta. Multiphoton microscopy is used to image the associated regional microstructure. Exponential-based and recruitment-based constitutive models are used to account for the observed mechanical behavior while considering the aortic wall as a composite of two layers with independent properties. An elevated stiffness is observed in distal regions compared to proximal regions of thoracic aorta, consistent with sharper and earlier collagen recruitment estimated for medial and adventitial layers in the models. Multiphoton images further support our prediction that higher stiffness in distal regions is associated with less undulation in collagen fibers. Recruitment-based models further reveal that regardless of the location, collagen in the media is recruited from the onset of stretching, whereas adventitial collagen starts to engage with a delay. A parameter sensitivity analysis is performed to discriminate between the models in terms of the confidence in the estimated model parameters. PMID:25612301

  17. EFFECT OF AGE ON MECHANICAL PROPERTIES OF THE COLLAGEN PHASE IN DIFFERENT ORIENTATIONS OF HUMAN CORTICAL BONE

    PubMed Central

    Leng, Huijie; Reyes, Michael J; Dong, Neil X; Wang, Xiaodu

    2013-01-01

    The collagen phase plays an important role in mechanical behaviors of cortical bone. However, aging effects on the mechanical behavior of the collagen phase is still poorly understood. In this study, micro-tensile tests were performed on demineralized human cortical bone samples from young, middle-aged, and elderly donors and aging effects on the mechanical properties of the collagen phase in different orientations (i.e. longitudinal and transverse directions of bone) were examined. The results of this study indicated that the elastic modulus and ultimate strength of the demineralized bone specimens decreased with aging in both the longitudinal and transverse orientations. However, the failure strain exhibited no significant changes in both orientations regardless of aging. These results suggest that the stiffness and strength of the collagen phase in bone are deteriorated with aging in both longitudinal and transverse directions. However, the aging effect is not reflected in the failure strain of the collagen phase in both longitudinal and transverse orientations, implying that the maximum sustainable deformation of the collagen phase is independent of aging and orientation. PMID:23598045

  18. Regulation of collagen production in freshly isolated cell populations from normal and cirrhotic rat liver: Effect of lactate

    SciTech Connect

    Cerbon-Ambriz, J.; Cerbon-Solorzano, J.; Rojkind, M. )

    1991-03-01

    Previous work has shown that lactic acid, and to a lesser extent pyruvic acid, is able to increase collagen synthesis significantly in liver slices of CCl4-treated rats but not normal rats. The purpose of this report is to document which cells in the cirrhotic liver are responsible for the lactate-stimulated increase in collagen synthesis. It was found that (a) incorporation of 3H-proline into protein-bound 3H-hydroxyproline is increased threefold to fourfold in hepatocytes from CCl4-treated rats as compared with normal rat hepatocytes; (b) neither the hepatocytes from normal nor those from CCl4-treated rats modify their collagen synthesizing capacity when 30 mmol/L lactic acid was added to the incubation medium; (c) nonparenchymal cells obtained from livers of CCl4-treated rats synthesize much less collagen than hepatocytes, but their synthesis is stimulated twofold by lactic acid; (d) from the different nonparenchymal cells, only fat-storing (Ito) cells increase collagen synthesis when lactic acid is present in the incubation medium. These results suggest that the increased lactic acid levels observed in patients with alcoholic hepatic cirrhosis may play an important role in the development of fibrosis by stimulating collagen production by fat-storing (Ito) cells.

  19. Engineering D-Amino Acid Containing Collagen Like Peptide at the Cleavage Site of Clostridium histolyticum Collagenase for Its Inhibition

    PubMed Central

    Velmurugan, Punitha; Jonnalagadda, Raghava Rao; Unni Nair, Balachandran

    2015-01-01

    Collagenase is an important enzyme which plays an important role in degradation of collagen in wound healing, cancer metastasis and even in embryonic development. However, the mechanism of this degradation has not yet been completely understood. In the field of biomedical and protein engineering, the design and development of new peptide based materials is of main concern. In the present work an attempt has been made to study the effect of DAla in collagen like peptide (imino-poor region of type I collagen) on the structure and stability of peptide against enzyme hydrolysis. Effect of replacement of DAla in the collagen like peptide has been studied using circular dichroic spectroscopy (CD). Our findings suggest that, DAla substitution leads to conformational changes in the secondary structure and favours the formation of polyproline II conformation than its L-counterpart in the imino-poor region of collagen like peptides. Change in the chirality of alanine at the cleavage site of collagenase in the imino-poor region inhibits collagenolytic activity. This may find application in design of peptides and peptidomimics for enzyme-substrate interaction, specifically with reference to collagen and other extra cellular matrix proteins. PMID:25973613

  20. Cysticercus fasciolaris infection in wild rats (Rattus norvegicus) in Korea and formation of cysts by remodeling of collagen fibers.

    PubMed

    Lee, Byung-Woo; Jeon, Byung-Suk; Kim, Hak-Soo; Kim, Hyeon-Cheol; Yoon, Byung-Il

    2016-05-01

    Cysticercus fasciolaris, the larval form of Taenia taeniaeformis, is commonly encountered in rodents. In our study, 287 wild rats (Rattus norvegicus) in South Korea were examined in 2010 and 2011. Of 287 rats, 97 (33.8%) were infected with C. fasciolaris A strong positive correlation was found between the host body weight and prevalence in both sexes, regardless of the year of collection. The liver was the most common habitat of the parasite, and the lung was the most frequent ectopic region, followed by mesentery, pleura, abdominal wall, and kidney. The lesions of the affected organs were generally characterized by well-developed cysts, each containing a larva. However, the cysts within kidney and abdominal wall were poorly organized, filled with abscess, and lacked larvae. Collagen types I and III, but not type IV, played significant roles in constructing the cysts at differential stages, addressed by immunohistochemistry. During cyst wall development, both collagen types contributed equally to cyst formation at the early stage, whereas collagen type I was the major component at the late stage (p < 0.05). In early-stage cysts, distribution of collagens was interestingly differential depending on the development stage, as collagen type I was localized in the outer layer and type III was located in the inner layer. Our results suggest that an appropriate remodeling process of collagen fibers is necessary for C. fasciolaris to build the well-conditioned cysts in the target organs for survival. PMID:27075846

  1. Characterization of pepsin-solubilized bovine heart-valve collagen.

    PubMed Central

    Bashey, R I; Bashey, H M; Jimenez, S A

    1978-01-01

    Collagens extracted from heart valves by using limited pepsin digestion were fractionated by differential salt precipitation. Collagen types were identified by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, amino acid analysis and cleavage with CNBr. Heart-valve collagen was heterogeneous in nature, consisting of a mixture of type-I and type-III collagens. The identity of type-III collagen was established on the basis of (a) insolubility in 1.7 M-NaC1 at neutral pH, (b) behaviour of this collagen fraction on gel electrophoresis under reducing and non-reducing conditions, (c) amino acid analysis showing a hydroxyproline/proline ratio greater than 1, and (d) profile of CNBr peptides on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis showing a peak characteristic for type-III collagen containing peptides alpha1(III)CB8 and alpha1(III)CB3. In addition to types-I and -III collagen, a collagen polypeptide not previously described in heart valves was identified. This polypeptide represented approx. 30% of the collagen fraction precipitated at 4.0 M-NaCl, it migrated between beta- and alpha1-collagen chains on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and its electrophoretic behaviour was not affected by disulphide-bond reduction. All collagen fractions from the heart valves contained increased amounts of hydroxylysine when compared with type-I and -III collagens from other tissues. The presence of beta- and gamma-chains and higher aggregates in pepsin-solubilized collagen indicated that these collagens were highly cross-linked and suggested that some of these cross-links involved the triple-helical regions of the molecule. It is likely that the higher hydroxylysine content of heart-valve collagen is responsible for the high degree of intermolecular cross-linking and may be the result of an adaptive mechanism for the specialized function of these tissues. Images Fig. 5. PMID:361035

  2. Visualisation of newly synthesised collagen in vitro and in vivo

    PubMed Central

    Oostendorp, Corien; Uijtdewilligen, Peter J.E.; Versteeg, Elly M.; Hafmans, Theo G.; van den Bogaard, Ellen H.; de Jonge, Paul K.J.D.; Pirayesh, Ali; Von den Hoff, Johannes W.; Reichmann, Ernst; Daamen, Willeke F.; van Kuppevelt, Toin H.

    2016-01-01

    Identifying collagen produced de novo by cells in a background of purified collagenous biomaterials poses a major problem in for example the evaluation of tissue-engineered constructs and cell biological studies to tumor dissemination. We have developed a universal strategy to detect and localize newly deposited collagen based on its inherent association with dermatan sulfate. The method is applicable irrespective of host species and collagen source. PMID:26738984

  3. Immunosuppression by fractionated total lymphoid irradiation in collagen arthritis

    SciTech Connect

    McCune, W.J.; Buckley, J.A.; Belli, J.A.; Trentham, D.E.

    1982-05-01

    Treatments with fractionated total lymphoid irradiation (TLI) and cyclophosphamide were evaluated for rats injected with type II collagen. Preadministration of TLI and repeated injections of cyclophosphamide suppressed the severity of arthritis and lowered antibody titers to collagen significantly. TLI initiated at the onset of collagen arthritis decreased humoral and cellular responses to collagen but did not affect the severity of arthritis. These data demonstrate that both TLi and cyclophosphamide are immunosuppressive in an experimentally inducible autoimmune disease.

  4. Pathways to Play: Developing Play Skills in Young Children.

    ERIC Educational Resources Information Center

    Heidemann, Sandra; Hewitt, Deborah

    Play skills are vital to a child's overall healthy development. However, the training many caregivers receive may not include extensive information on play skills. This book presents a play checklist to help caregivers observe children's play skills, pinpoint play skills on which children need to work, and plan goals for improving those play…

  5. Dense fibrillar collagen is a master activator of invadopodia

    PubMed Central

    Artym, Vira V.

    2016-01-01

    ABSTRACT Tumor stroma is characterized by abnormal accumulation of dense fibrillar collagen, which promotes tumor progression and metastasis. However, the effect of desmoplastic collagen on cells has been unclear. Our recent findings demonstrate that dense fibrillar collagen activates a novel phosphosignaling mechanism for robust induction of invadopodia in tumor cells and normal fibroblasts. PMID:27314068

  6. Collagen network strengthening following cyclic tensile loading.

    PubMed

    Susilo, Monica E; Paten, Jeffrey A; Sander, Edward A; Nguyen, Thao D; Ruberti, Jeffrey W

    2016-02-01

    The bulk mechanical properties of tissues are highly tuned to the physiological loads they experience and reflect the hierarchical structure and mechanical properties of their constituent parts. A thorough understanding of the processes involved in tissue adaptation is required to develop multi-scale computational models of tissue remodelling. While extracellular matrix (ECM) remodelling is partly due to the changing cellular metabolic activity, there may also be mechanically directed changes in ECM nano/microscale organization which lead to mechanical tuning. The thermal and enzymatic stability of collagen, which is the principal load-bearing biopolymer in vertebrates, have been shown to be enhanced by force suggesting that collagen has an active role in ECM mechanical properties. Here, we ask how changes in the mechanical properties of a collagen-based material are reflected by alterations in the micro/nanoscale collagen network following cyclic loading. Surprisingly, we observed significantly higher tensile stiffness and ultimate tensile strength, roughly analogous to the effect of work hardening, in the absence of network realignment and alterations to the fibril area fraction. The data suggest that mechanical loading induces stabilizing changes internal to the fibrils themselves or in the fibril-fibril interactions. If such a cell-independent strengthening effect is operational in vivo, then it would be an important consideration in any multiscale computational approach to ECM growth and remodelling. PMID:26855760

  7. Temporary granulomatous inflammation following collagen implantation.

    PubMed

    Heise, H; Zimmermann, R; Heise, P

    2001-08-01

    Injections of bovine collagen are a common procedure for correction of folds in the face. However, this therapy is not free from side effects. We present a patient in whom a granulomatous inflammation occurred following implantation of this material. We therefore now insist on an observation interval of 4 weeks between test injection and actual treatment, as is recommended by the manufacturer. PMID:11562094

  8. Microfibrillar collagen in the oval window.

    PubMed

    Liston, S L

    1982-01-01

    Compressed microfibrillar collagen was used to seal openings in cat oval windows. Histologic examination showed the material was well tolerated and produced a good oval window seal. Because of its hemostatic properties, this material should prove to be useful when bleeding is encountered during a stapedectomy. PMID:10994440

  9. Biological safety of fish (tilapia) collagen.

    PubMed

    Yamamoto, Kohei; Igawa, Kazunari; Sugimoto, Kouji; Yoshizawa, Yuu; Yanagiguchi, Kajiro; Ikeda, Takeshi; Yamada, Shizuka; Hayashi, Yoshihiko

    2014-01-01

    Marine collagen derived from fish scales, skin, and bone has been widely investigated for application as a scaffold and carrier due to its bioactive properties, including excellent biocompatibility, low antigenicity, and high biodegradability and cell growth potential. Fish type I collagen is an effective material as a biodegradable scaffold or spacer replicating the natural extracellular matrix, which serves to spatially organize cells, providing them with environmental signals and directing site-specific cellular regulation. This study was conducted to confirm the safety of fish (tilapia) atelocollagen for use in clinical application. We performed in vitro and in vivo biological studies of medical materials to investigate the safety of fish collagen. The extract of fish collagen gel was examined to clarify its sterility. All present sterility tests concerning bacteria and viruses (including endotoxin) yielded negative results, and all evaluations of cell toxicity, sensitization, chromosomal aberrations, intracutaneous reactions, acute systemic toxicity, pyrogenic reactions, and hemolysis were negative according to the criteria of the ISO and the Ministry of Health, Labour and Welfare of Japan. The present study demonstrated that atelocollagen prepared from tilapia is a promising biomaterial for use as a scaffold in regenerative medicine. PMID:24809058

  10. Separation of type IX collagen from other cartilage collagens by hydrophobic interaction chromatography.

    PubMed

    Macek, J; Lichý, A; Tesarová, E; Adam, M

    1988-12-30

    Collagen type IX was separated from other cartilage collagens (types II and XI) by hydrophobic interaction chromatography on a 25 cm X 8 mm I.D. stainless-steel column packed with Separon HEMA 1000 Bio. The mobile phase was 0.84 M ammonium sulphate with 0.1 M potassium dihydrogenphosphate (pH 6.5). Under these conditions only collagen type IX was eluted from the column; it could be monitored with UV detection (218 nm) or selectively with fluorescence detection (excitation 330 nm, emission filter 389 nm). The method can be used for the isolation and quantitation of collagen type IX. The assay was linear in the range 0-10 micrograms, the correlation coefficient was 0.99, precision 5.5% and accuracy 13%. The detection limit was about 0.6 microgram. PMID:3246532

  11. Collagen esterification enhances the function and survival of pancreatic β cells in 2D and 3D culture systems

    SciTech Connect

    Ko, Jae Hyung; Kim, Yang Hee; Jeong, Seong Hee; Lee, Song; Park, Si-Nae; Shim, In Kyong; Kim, Song Cheol

    2015-08-07

    Collagen, one of the most important components of the extracellular matrix (ECM), may play a role in the survival of pancreatic islet cells. In addition, chemical modifications that change the collagen charge profile to a net positive charge by esterification have been shown to increase the adhesion and proliferation of various cell types. The purpose of this study was to characterize and compare the effects of native collagen (NC) and esterified collagen (EC) on β cell function and survival. After isolation by the collagenase digestion technique, rat islets were cultured with NC and EC in 2 dimensional (2D) and 3 dimensional (3D) environments for a long-term duration in vitro. The cells were assessed for islet adhesion, morphology, viability, glucose-induced insulin secretion, and mRNA expression of glucose metabolism-related genes, and visualized by scanning electron microscopy (SEM). Islet cells attached tightly in the NC group, but islet cell viability was similar in both the NC and EC groups. Glucose-stimulated insulin secretion was higher in the EC group than in the NC group in both 2D and 3D culture. Furthermore, the mRNA expression levels of glucokinase in the EC group were higher than those in the NC group and were associated with glucose metabolism and insulin secretion. Finally, SEM observation confirmed that islets had more intact component cells on EC sponges than on NC sponges. These results indicate that modification of collagen may offer opportunities to improve function and viability of islet cells. - Highlights: • We changed the collagen charge profile to a net positive charge by esterification. • Islets cultured on esterified collagen improved survival in both 2D and 3D culture. • Islets cultured on esterified collagen enhanced glucose-stimulated insulin release. • High levels of glucokinase mRNA may be associated with increased insulin release.

  12. Zosteriform Collagen Nevus in an Infant.

    PubMed

    Aksu Çerman, Aslı; Aktaş, Ezgi; Kıvanç Altunay, Ilknur Kıvanç; Demirkesen, Cuyan

    2016-06-01

    Connective tissue nevi (CTN) are dermal hamartomas characterized by an imbalance in the amount and distribution of the normal components of the extracellular dermal matrix, specifically collagen, elastin, and/or proteoglicans. The term "CTN" was first mentioned by Lewandowsky in 1921 (1), although it was not accepted until the review by Gutmann in 1926 (2). Classification of CTN was established by Uitto et al. (3) in 1980 according to clinical, genetic, and histopathological features. But this classification did not include zosteriform nevi. The more recent Pierard and Lapiere (4) classification seems to be a more suitable method of classification for zosteriform nevi. They classified CTN into two groups: (1) reticular and (2) adventitial. Zosteriform nevus is a rare form of reticular CTN that is diagnosed according to its clinical distribution. Here we report a collagen nevus in an infant that followed a zosteriform pattern. An 8-month-old girl presented with flesh-colored plaques on the right buttock in a zosteriform distribution, which had been present since birth. The plaques appeared to be well-defined cobblestone-like nodules on palpation (Figure 1). Systemic examination, laboratory tests and radiologic examinations did not reveal any abnormalities. The patient had no associated disease and no history of similar skin findings among family members. A skin punch biopsy was performed from one of the nodules. The histopathologic examination showed significantly increased density of thickened collagen fibers in the lower dermis and subcutaneous tissue. Verhoeff-van Gieson and orcein stains demonstrated the presence of dense collagen fibers with diminished elastic fibers (Figure 2). Four subtypes of collagen tissue nevus have been described: (I) familial cutaneous collagenoma, (II) shagreen patches in tuberous sclerosis, (III) eruptive collagenoma, (IV) and isolated collagenoma (5). Isolated collagenoma with lack of family history is fairly rare. It is sporadic

  13. Ovine-Based Collagen Matrix Dressing: Next-Generation Collagen Dressing for Wound Care

    PubMed Central

    Bohn, Gregory; Liden, Brock; Schultz, Gregory; Yang, Qingping; Gibson, Daniel J.

    2016-01-01

    Significance: Broad-spectrum metalloproteinase (MMP) reduction along with inherent aspects of an extracellular matrix (ECM) dressing can bring about improved wound healing outcomes and shorter treatment duration. Initial reports of clinical effectiveness of a new ovine-based collagen extracellular matrix (CECM) dressing demonstrate benefits in chronic wound healing. Recent Advances: CECM dressings are processed differently than oxidized regenerated cellulose/collagen dressings. CECM dressings consist primarily of collagens I and III arranged as native fibers that retain the three-dimensional architecture present in tissue ECM. As such, ovine-based ECM dressings represent a new generation of collagen dressings capable of impacting a broad spectrum of MMP excess known to be present in chronic wounds. Critical Issues: While MMPs are essential in normal healing, elevated presence of MMPs has been linked to wound failure. Collagen has been shown to reduce levels of MMPs, acting as a sacrificial substrate for excessive proteases in a chronic wound. Preserving collagen dressings in a more native state enhances bioactivity in terms of the ability to affect the chronic wound environment. Clinical observation and assessment may not be sufficient to identify a wound with elevated protease activity that can break down ECM, affect wound fibroblasts, and impair growth factor response. Future Directions: Collagen dressings that target broad-spectrum excessive MMP levels and can be applied early in the course of care may positively impact healing rates in difficult wounds. Next-generation collagen dressings offer broader MMP reduction capacity while providing a provisional dermal matrix or ECM. PMID:26858910

  14. Molecular crowding of collagen: a pathway to produce highly-organized collagenous structures.

    PubMed

    Saeidi, Nima; Karmelek, Kathryn P; Paten, Jeffrey A; Zareian, Ramin; DiMasi, Elaine; Ruberti, Jeffrey W

    2012-10-01

    Collagen in vertebrate animals is often arranged in alternating lamellae or in bundles of aligned fibrils which are designed to withstand in vivo mechanical loads. The formation of these organized structures is thought to result from a complex, large-area integration of individual cell motion and locally-controlled synthesis of fibrillar arrays via cell-surface fibripositors (direct matrix printing). The difficulty of reproducing such a process in vitro has prevented tissue engineers from constructing clinically useful load-bearing connective tissue directly from collagen. However, we and others have taken the view that long-range organizational information is potentially encoded into the structure of the collagen molecule itself, allowing the control of fibril organization to extend far from cell (or bounding) surfaces. We here demonstrate a simple, fast, cell-free method capable of producing highly-organized, anistropic collagen fibrillar lamellae de novo which persist over relatively long-distances (tens to hundreds of microns). Our approach to nanoscale organizational control takes advantage of the intrinsic physiochemical properties of collagen molecules by inducing collagen association through molecular crowding and geometric confinement. To mimic biological tissues which comprise planar, aligned collagen lamellae (e.g. cornea, lamellar bone or annulus fibrosus), type I collagen was confined to a thin, planar geometry, concentrated through molecular crowding and polymerized. The resulting fibrillar lamellae show a striking resemblance to native load-bearing lamellae in that the fibrils are small, generally aligned in the plane of the confining space and change direction en masse throughout the thickness of the construct. The process of organizational control is consistent with embryonic development where the bounded planar cell sheets produced by fibroblasts suggest a similar confinement/concentration strategy. Such a simple approach to nanoscale

  15. Tuning 3D Collagen Matrix Stiffness Independently of Collagen Concentration Modulates Endothelial Cell Behavior

    PubMed Central

    Mason, Brooke N.; Starchenko, Alina; Williams, Rebecca M.; Bonassar, Lawrence J.; Reinhart-King, Cynthia A.

    2012-01-01

    Numerous studies have described the effects of matrix stiffening on cell behavior using two dimensional (2D) synthetic surfaces; however less is known about the effects of matrix stiffening on cells embedded in three dimensional (3D) in vivo-like matrices. A primary limitation in investigating the effects of matrix stiffness in 3D is the lack of materials that can be tuned to control stiffness independently of matrix density. Here, we use collagen-based scaffolds where the mechanical properties are tuned using non-enzymatic glycation of the collagen in solution, prior to polymerization. Collagen solutions glycated prior to polymerization result in collagen gels with a 3-fold increase in compressive modulus without significant changes to the collagen architecture. Using these scaffolds, we show that endothelial cell spreading increases with matrix stiffness, as does the number and length of angiogenic sprouts and the overall spheroid outgrowth. Differences in sprout length are maintained even when the receptor for advanced glycation endproducts is inhibited. Our results demonstrate the ability to de-couple matrix stiffness from matrix density and structure in collagen gels, and that increased matrix stiffness results in increased sprouting and outgrowth. PMID:22902816

  16. IL-13 mediates collagen deposition via STAT6 and microRNA-135b: a role for epigenetics

    PubMed Central

    O’Reilly, Steven; Ciechomska, Marzena; Fullard, Nicola; Przyborski, Stefan; van Laar, Jacob M.

    2016-01-01

    Systemic sclerosis is an autoimmune connective tissue disease in which T cells play a prominent role. We and others have previously demonstrated a role for T cell-derived IL-13 in mediating the induction of collagen in dermal fibroblasts and that blockade with IL-13 antibodies attenuates this increase. In this study we want to probe the signalling that underpins IL-13 mediated matrix deposition. Isolated dermal fibroblasts were incubated with recombinant IL-13 and gene expression by qRT-PCR was performed for collagen1A1 and TGF-β1. Small interfering RNA (siRNA) was used to knock down STAT6 and a small molecule inhibitor was also used to block this pathway. MiR-135b was transfected into fibroblasts plus and minus IL-13 to see if this miR plays a role. miR-135b was measured in systemic sclerosis fibroblasts isolated from patients and also in serum. Results showed that IL-13 increased collagen expression and that this is independent from TGF-β1. This is dependent on STAT6 as targeting this blocked induction. MiR-135b reduces collagen induction in fibroblasts and scleroderma fibroblasts have lower constitutive levels of the miR. We further demonstrate that miR135b is repressed by methylation and may include MeCP2. In conclusion we show that STAT6 and miR-135b regulate IL-13-mediated collagen production by fibroblasts. PMID:27113293

  17. IL-13 mediates collagen deposition via STAT6 and microRNA-135b: a role for epigenetics.

    PubMed

    O'Reilly, Steven; Ciechomska, Marzena; Fullard, Nicola; Przyborski, Stefan; van Laar, Jacob M

    2016-01-01

    Systemic sclerosis is an autoimmune connective tissue disease in which T cells play a prominent role. We and others have previously demonstrated a role for T cell-derived IL-13 in mediating the induction of collagen in dermal fibroblasts and that blockade with IL-13 antibodies attenuates this increase. In this study we want to probe the signalling that underpins IL-13 mediated matrix deposition. Isolated dermal fibroblasts were incubated with recombinant IL-13 and gene expression by qRT-PCR was performed for collagen1A1 and TGF-β1. Small interfering RNA (siRNA) was used to knock down STAT6 and a small molecule inhibitor was also used to block this pathway. MiR-135b was transfected into fibroblasts plus and minus IL-13 to see if this miR plays a role. miR-135b was measured in systemic sclerosis fibroblasts isolated from patients and also in serum. Results showed that IL-13 increased collagen expression and that this is independent from TGF-β1. This is dependent on STAT6 as targeting this blocked induction. MiR-135b reduces collagen induction in fibroblasts and scleroderma fibroblasts have lower constitutive levels of the miR. We further demonstrate that miR135b is repressed by methylation and may include MeCP2. In conclusion we show that STAT6 and miR-135b regulate IL-13-mediated collagen production by fibroblasts. PMID:27113293

  18. In vitro formation and thermal transition of novel hybrid fibrils from type I fish scale collagen and type I porcine collagen

    NASA Astrophysics Data System (ADS)

    Chen, Song; Ikoma, Toshiyuki; Ogawa, Nobuhiro; Migita, Satoshi; Kobayashi, Hisatoshi; Hanagata, Nobutaka

    2010-06-01

    Novel type I collagen hybrid fibrils were fabricated by neutralizing a mixture of type I fish scale collagen solution and type I porcine collagen solution with a phosphate buffer saline at 28 °C. Their structure was discussed in terms of the volume ratio of fish/porcine collagen solution. Scanning electron and atomic force micrographs showed that the diameter of collagen fibrils derived from the collagen mixture was larger than those derived from each collagen, and all resultant fibrils exhibited a typical D-periodic unit of ~67 nm, irrespective of volume ratio of both collagens. Differential scanning calorimetry revealed only one endothermic peak for the fibrils derived from collagen mixture or from each collagen solution, indicating that the resultant collagen fibrils were hybrids of type I fish scale collagen and type I porcine collagen.

  19. [Study on the n = 5 complex transitions for ions Nd XIII-Sm XV in Cd I isoelectronic sequence].

    PubMed

    Ding, Kai; Mu, Zhi-Dong; Ye, Shi-Wang

    2011-01-01

    The energy levels of the n = 5 complex configuration 5s2, 5s5p, 5s5d and 5p2 were computed for Cd I isoelectronic sequence ions from I VI to Sm XV by Hartree-Fock with relativistic corrections (HFR) method. By analyzing the variation of difference deltaE between energy levels calculated by HFR method and the experimental values with Z(c) along this isoelectronic sequence, the authors put forward a new fitting formula for generalized-least-square-fit (LSF) calculation. Using this formula and the FORTRAN programme designed by us, the energy levels of configurations mentioned above were calculated. The unknown energy levels of configuration 5s2 , 5s5p, 5s5d and 5p2 for ions from Nd XIII-Sm XV were predicted by extrapolation (or interpolation). Also, the wavelengths and HFR probabilities of transition 5s2-5s5p, 5s5p-5p2 and 5s5p-5s5d were computed. The calculated energy levels and wavelength results are in good agreement with corresponding experimental data reported in the references. PMID:21428048

  20. Venezuela-MEM/USA-DOE Fossil Energy Report XIII-1, Supporting Technology for Enhanced Oil Recovery, Microbial EOR

    SciTech Connect

    Ziritt, Jose Luis

    1999-11-03

    The results from Annex XIII of the Cooperative Agreement between the United States Department of Energy (DOE) and the Ministry of Energy and Mines of the Republic of Venezuela (MEMV) have been documented and published with many researchers involved. Integrate comprehensive research programs in the area of Microbial Enhanced Oil Recovery (MEOR) ranged from feasibility laboratory studies to full-scale multi-well field pilots. The objective, to cooperate in a technical exchange of ideas and information was fully met throughout the life of the Annex. Information has been exchanged between the two countries through published reports and technical meetings between experts in both country's research communities. The meetings occurred every two years in locations coincident with the International MEOR conferences & workshops sponsored by DOE (June 1990, University of Oklahoma, September 1992, Brookhaven, September 1995, National Institute of Petroleum and Energy Research). Reports and publications produced during these years are listed in Appendix B. Several Annex managers have guided the exchange through the years. They included Luis Vierma, Jose Luis Zirritt, representing MEMV and E. B. Nuckols, Edith Allison, and Rhonda Lindsey, representing the U.S. DOE. Funding for this area of research remained steady for a few years but decreased in recent years. Because both countries have reduced research programs in this area, future exchanges on this topic will occur through ANNEX XV. Informal networks established between researchers through the years should continue to function between individuals in the two countries.

  1. Exploring a Role in Tanning for the Gap Region of the Collagen Fibril: Catechin-Collagen Interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electron micrographs of stained collagen fibrils display a pattern of alternating light and dark bands perpendicular to the axis of the collagen fibril. Light bands correspond to regions of more dense lateral packing where adjacent collagen monomers overlap, and dark bands correspond to 'gap' regio...

  2. Development through Work and Play.

    ERIC Educational Resources Information Center

    Hartung, Paul J.

    2002-01-01

    Five proposals are made for incorporating a work-play perspective in career development research: (1) fuse work and play conceptually over the life course; (2) imbue developmental career theory with a work-play fusion; (3) study work and play across the life span; (4) investigate work and play within the life space; and (5) consider a work-play…

  3. Play Theories: A Contemporary Review.

    ERIC Educational Resources Information Center

    Mellou, Eleni

    1994-01-01

    Reviews two sets of play theories, classical and modern, noting that the reason and purpose for play are explained by classical theories; the role of play in child development, determined by modern theories. States that process of play has dual functions of personal expression and social adaptation. Examines the relationship between play and…

  4. Play: Working Partner of Growth.

    ERIC Educational Resources Information Center

    McKee, Judy Spitler, Ed.

    This volume is a collection of nine papers focusing on different aspects of play. The first section, "Play, Growth, Development, and Learning," contains discussions dealing with make-believe play and learning; an all-in-fun approach to thinking, playing, and language learning for young children; and ways children learn through play. The second…

  5. Farm Hall: The Play

    NASA Astrophysics Data System (ADS)

    Cassidy, David C.

    2013-03-01

    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  6. Surface modification of electrospun PLGA scaffold with collagen for bioengineered skin substitutes.

    PubMed

    Sadeghi, A R; Nokhasteh, S; Molavi, A M; Khorsand-Ghayeni, M; Naderi-Meshkin, H; Mahdizadeh, A

    2016-09-01

    In skin tissue engineering, surface feature of the scaffolds plays an important role in cell adhesion and proliferation. In this study, non-woven fibrous substrate based on poly (lactic-co-glycolic acid) (PLGA) (75/25) were hydrolyzed in various concentrations of NaOH (0.05N, 0.1N, 0.3N) to increase carboxyl and hydroxyl groups on the fiber surfaces. These functional groups were activated by EDC/NHS to create chemical bonding with collagen. To improve bioactivity, the activated substrates were coated with a collagen solution (2mg/ml) and cross-linking was carried out using the EDC/NHS in MES buffer. The effectiveness of the method was evaluated by contact angle measurements, porosimetry, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), tensile and degradation tests as well as in vitro cell attachment and cytotoxicity assays. Cell culture results of human dermal fibroblasts (HDF) and keratinocytes cell line (HaCat) revealed that the cells could attach to the scaffold. Further investigation with MTT assay showed that the cell proliferation of HaCat significantly increases with collagen coating. It seems that sufficient stability of collagen on the surface due to proper chemical bonding and cross-linking has increased the bioactivity of surface remarkably which can be promising for bioengineered skin applications. PMID:27207046

  7. Preserving the longevity of long-lived type II collagen and its implication for cartilage therapeutics.

    PubMed

    Tiku, Moti L; Madhan, Balaraman

    2016-07-01

    Human life expectancy has been steadily increasing at a rapid rate, but this increasing life span also brings about increases in diseases, dementia, and disability. A global burden of disease 2010 study revealed that hip and knee osteoarthritis ranked the 11th highest in terms of years lived with disability. Wear and tear can greatly influence the quality of life during ageing. In particular, wear and tear of the articular cartilage have adverse effects on joints and result in osteoarthritis. The articular cartilage uses longevity of type II collagen as the foundation around which turnover of proteoglycans and the homeostatic activity of chondrocytes play central roles thereby maintaining the function of articular cartilage in the ageing. The longevity of type II collagen involves a complex interaction of the scaffolding needs of the cartilage and its biochemical, structural and mechanical characteristics. The covalent cross-linking of heterotypic polymers of collagens type II, type IX and type XI hold together cartilage, allowing it to withstand ageing stresses. Discerning the biological clues in the armamentarium for preserving cartilage appears to be collagen cross-linking. Therapeutic methods to crosslink in in-vivo are non-existent. However intra-articular injections of polyphenols in vivo stabilize the cartilage and make it resistant to degradation, opening a new therapeutic possibility for prevention and intervention of cartilage degradation in osteoarthritis of aging. PMID:27133944

  8. Cloning, expression and antioxidant activity of a novel collagen from Pelodiscus sinensis.

    PubMed

    Xu, Ran; Li, Dengfeng; Peng, Jiao; Fang, Jing; Zhang, Liping; Liu, Lianguo

    2016-06-01

    Collagen is the main structural protein of various connective tissues in animals and naturally plays an important role within the body. It is increasingly used within certain areas, such as medicine, citology and cosmetology. The soft-shelled turtle (Pelodiscus sinensis) is a commercially important aquatic species rich in collagen. In this study, a novel collagen gene fragment of 756 bp, which encodes 252 deduced amino acid residues, including 25 conserved Gly-X-Y motifs, was cloned from a soft-shelled turtle. Recombinant soft-shelled turtle collagen (rSTC) was stably expressed in Escherichia coli Rosetta and purified by His GraviTrap affinity columns. The antioxidant activities of rSTC were measured using hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The results showed that rSTC quenched the free radicals in a dose-dependent manner. The hydroxyl radical scavenging activity (HRSA) of rSTC was 98.9 % at a concentration of 3 mg/mL. At a concentration of 5 mg/mL, rSTC exhibited a DPPH radical scavenging activity of 32.7 %. At the tested concentrations, rSTC exhibited higher HRSA and lower DPPH radical scavenging activity. PMID:27116966

  9. Effect of Surface Chemical Functionalities on Collagen Deposition by Primary Human Dermal Fibroblasts.

    PubMed

    Bachhuka, Akash; Hayball, John; Smith, Louise E; Vasilev, K

    2015-10-28

    Surface modification has been identified as an important technique that could improve the response of the body to implanted medical devices. Collagen production by fibroblasts is known to play a vital role in wound healing and device fibrous encapsulation. However, how surface chemistry affects collagen I and III deposition by these cells has not been systematically studied. Here, we report how surface chemistry influences the deposition of collagen I and III by primary human dermal fibroblasts. Amine (NH3), carboxyl acid (COOH), and hydrocarbon (CH3) surfaces were generated by plasma deposition. This is a practically relevant tool to deposit a functional coating on any type of substrate material. We show that fibroblasts adhere better and proliferate faster on amine-rich surfaces. In addition, the initial collagen I and III production is greater on this type of coating. These data indicates that surface modification can be a promising route for modulating the rate and level of fibrous encapsulation and may be useful in informing the design of implantable biomedical devices to produce more predictable clinical outcomes. PMID:26457649

  10. Peroxidase Enzymes Regulate Collagen Biosynthesis and Matrix Mineralization by Cultured Human Osteoblasts.

    PubMed

    DeNichilo, Mark O; Shoubridge, Alexandra J; Panagopoulos, Vasilios; Liapis, Vasilios; Zysk, Aneta; Zinonos, Irene; Hay, Shelley; Atkins, Gerald J; Findlay, David M; Evdokiou, Andreas

    2016-03-01

    The early recruitment of inflammatory cells to sites of bone fracture and trauma is a critical determinant in successful fracture healing. Released by infiltrating inflammatory cells, myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are heme-containing enzymes, whose functional involvement in bone repair has mainly been studied in the context of providing a mechanism for oxidative defense against invading microorganisms. We report here novel findings that show peroxidase enzymes have the capacity to stimulate osteoblastic cells to secrete collagen I protein and generate a mineralized extracellular matrix in vitro. Mechanistic studies conducted using cultured osteoblasts show that peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl hydroxylase-dependent manner, which does not require ascorbic acid. Our studies demonstrate that osteoblasts rapidly bind and internalize both MPO and EPO, and the catalytic activity of these peroxidase enzymes is essential to support collagen I biosynthesis and subsequent release of collagen by osteoblasts. We show that EPO is capable of regulating osteogenic gene expression and matrix mineralization in culture, suggesting that peroxidase enzymes may play an important role not only in normal bone repair, but also in the progression of pathological states where infiltrating inflammatory cells are known to deposit peroxidases. PMID:26643175

  11. Collagen-binding proteins of rat mammary tumor epithelial cells: A biochemical and immunological study

    SciTech Connect

    Wirl, G.; Pfaeffle, M. )

    1988-05-01

    Collagen-binding proteins were studied in mammary epithelial cells of 7,12-dimethylbenz(a)anthracene-induced rat mammary tumors. Using affinity chromatography on type I collagen-Sepharose and polyacrylamide slab gel electrophoresis, three major proteins of 34,000, 36,000, and 38,000 Da were found. Pulse-chase experiments did not indicate a precursor-product relationship of these proteins. Tryptic/chymotryptic peptide maps, however, revealed that the 36,000- and 38,000-Da proteins are very similar but are quite different from the 34,000-Da molecular form. The distribution and function of these proteins were then analyzed by using polyclonal antibodies directed against the entire set of major proteins. In immunofluorescence studies the authors observed a dense, punctate distribution of fluorescence on the cell surface of isolated and unfixed epithelial organoids and a bright pericellular staining in cultures after fixation. Treatment with the antiserum did not affect attachment and spreading of cuboidal mammary cells to plastic or to a collagen substratum. However, when the antiserum was added to the medium of growing cuboidal cells, it caused the formation of duct-like structures. These studies indicate that collagen-binding proteins may play a role in mammary gland morphology.

  12. D-2-hydroxyglutarate produced by mutant IDH1 perturbs collagen maturation and basement membrane function

    PubMed Central

    Sasaki, Masato; Knobbe, Christiane B.; Itsumi, Momoe; Elia, Andrew J.; Harris, Isaac S.; Chio, Iok In Christine; Cairns, Rob A.; McCracken, Susan; Wakeham, Andrew; Haight, Jillian; Ten, Annick You; Snow, Bryan; Ueda, Takeshi; Inoue, Satoshi; Yamamoto, Kazuo; Ko, Myunggon; Rao, Anjana; Yen, Katharine E.; Su, Shinsan M.; Mak, Tak Wah

    2012-01-01

    Isocitrate dehydrogenase-1 (IDH1) R132 mutations occur in glioma, but their physiological significance is unknown. Here we describe the generation and characterization of brain-specific Idh1 R132H conditional knock-in (KI) mice. Idh1 mutation results in hemorrhage and perinatal lethality. Surprisingly, intracellular reactive oxygen species (ROS) are attenuated in Idh1-KI brain cells despite an apparent increase in the NADP+/NADPH ratio. Idh1-KI cells also show high levels of D-2-hydroxyglutarate (D2HG) that are associated with inhibited prolyl-hydroxylation of hypoxia-inducible transcription factor-1α (Hif1α) and up-regulated Hif1α target gene transcription. Intriguingly, D2HG also blocks prolyl-hydroxylation of collagen, causing a defect in collagen protein maturation. An endoplasmic reticulum (ER) stress response induced by the accumulation of immature collagens may account for the embryonic lethality of these mutants. Importantly, D2HG-mediated impairment of collagen maturation also led to basement membrane (BM) aberrations that could play a part in glioma progression. Our study presents strong in vivo evidence that the D2HG produced by the mutant Idh1 enzyme is responsible for the above effects. PMID:22925884

  13. Northern pike (Esox lucius) collagen: Extraction, characterization and potential application.

    PubMed

    Kozlowska, J; Sionkowska, A; Skopinska-Wisniewska, J; Piechowicz, K

    2015-11-01

    Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the scales of northern pike (Esox lucius) were extracted and characterized. It was the first time that this species was used as sources of collagen. FT-IR and amino acid analysis results revealed the presence of collagen. Glycine accounts for one-third of its amino acid residues and specific for collagen amino acid - hydroxyproline - is present in isolated protein. The content of imino acid: proline and hydroxyproline in ASC and PSC was similar (12.5% Pro and 6.5% Hyp). Both ASC and PSC were type I collagen. The denaturation temperature of ASC and PSC were 28.5 and 27°C, respectively. Thin collagen films were obtained by casting of collagen solution onto glass plates. The surface properties of ASC and PSC films were different - the surface of ASC collagen film was more polar and less rough than PSC and we can observe the formation of collagen fibrils after solvent evaporation. ASC films showed much higher tensile properties than PSC. The obtained results suggest that northern pike scales have potential as an alternative source of collagen for use in various fields. PMID:26254247

  14. Preparation of (3H)collagen for studies of the biologic fate of xenogenic collagen implants in vivo

    SciTech Connect

    McPherson, J.M.; Sawamura, S.J.; Conti, A.

    1986-06-01

    Reduction of a commercially available, pepsin-solubilized, bovine dermal collagen (Vitrogen 100) with sodium (3H)borohydride provided radiolabeled collagen preparations with specific activities ranging from 7.1-12.0 muCi/mg collagen. These specific activities were 2-3 times greater than those obtained by reduction of intact rat tail tendon collagen under similar conditions. The alpha, beta, and higher aggregate components of type I collagen were radiolabeled as well as the alpha component of a small amount of type III collagen present in the samples. Fractionation of cyanogen bromide peptides showed that alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB3,5 were the predominant peptides labeled by this procedure. Amino acid analysis indicated that the majority of the radioactivity was in reducible cross-links, precursors of these cross-links, and in hexosyllysine residues. Reconstitution experiments comparing this radiolabeled collagen with nonlabeled collagen showed them to be indistinguishable. Bacterial collagenase digestion of this reconstituted fibrillar collagen in both a lightly cross-linked (glutaraldehyde 0.0075%) and noncross-linked form provided evidence that digestion of labeled and nonlabeled collagens proceeded at similar rates. Thus, labeling did not change the properties of the collagen. Cross-linking made the preparation refractory to proteolytic degradation. Injection of fibrillar collagen preparations, spiked with radiolabeled collagen, into the guinea pig dermis followed by quantitation of the amount of radioactivity recovered from implant sites as a function of time, indicated that the lightly cross-linked samples also were more resistant to degradation in vivo than the noncross-linked preparation. The half-life of noncross-linked collagen was about 4 days while that of the cross-linked collagen was about 25 days.

  15. Increased collagen synthesis rate during wound healing in muscle.

    PubMed

    Zhou, Shaobo; Salisbury, Jonathan; Preedy, Victor R; Emery, Peter W

    2013-01-01

    Wound healing in muscle involves the deposition of collagen, but it is not known whether this is achieved by changes in the synthesis or the degradation of collagen. We have used a reliable flooding dose method to measure collagen synthesis rate in vivo in rat abdominal muscle following a surgical incision. Collagen synthesis rate was increased by 480% and 860% on days 2 and 7 respectively after surgery in the wounded muscle compared with an undamaged area of the same muscle. Collagen content was increased by approximately 100% at both day 2 and day 7. These results demonstrate that collagen deposition during wound healing in muscle is achieved entirely by an increase in the rate of collagen synthesis. PMID:23526975

  16. Type VII Collagen is Enriched in the Enamel Organic Matrix Associated with the Dentin-Enamel Junction of Mature Human Teeth

    PubMed Central

    McGuire, Jacob D.; Walker, Mary P.; Mousa, Ahmad; Wang, Yong; Gorski, Jeff P.

    2014-01-01

    The inner enamel region of erupted teeth is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the residual enamel organic matrix. Since enamel-forming ameloblasts are known to express type VII collagen and type VII collagen null mice display abnormal amelogenesis, the aim of this study was to determine whether type VII collagen is a component of the enamel organic matrix at the dentin-enamel junction (DEJ) of mature human teeth. Immunofluorescent confocal microscopy of demineralized tooth sections localized type VII collagen to the organic matrix surrounding individual enamel rods near the DEJ. Morphologically, immunoreactive type VII collagen helical-bundles resembled the gnarled-pattern of enamel rods detected by Coomassie Blue staining. Western blotting of whole crown or enamel matrix extracts also identified characteristic Mr=280 and 230 kDa type VII dimeric forms, which resolved into 75 and 25 kDa bands upon reduction. As expected, the collagenous domain of type VII collagen was resistant to pepsin digestion, but was susceptible to purified bacterial collagenase. These results demonstrate the inner enamel organic matrix in mature teeth contains macromolecular type VII collagen. Based on its physical association with the DEJ and its well-appreciated capacity to complex with other collagens, we hypothesize that enamel embedded type VII collagen fibrils may contribute not only to the structural resilience of enamel, but may also play a role in bonding enamel to dentin. PMID:24594343

  17. Child's Play: Revisiting Play in Early Childhood Settings.

    ERIC Educational Resources Information Center

    Dau, Elizabeth, Ed.; Jones, Elizabeth, Ed.

    Noting that play is an essential aspect of learning for young children, this book presents a collection of articles on children's play in Australia. Part 1, "Play, Development, and Learning," contains the following chapters: (1) "The Role of Play in Development and Learning" (Ann Glover); (2) "Stop, Look, and Listen: Adopting an Investigative…

  18. Imagination, Playfulness, and Creativity in Children's Play with Different Toys

    ERIC Educational Resources Information Center

    Mo????ller, Signe?? Juhl?

    2015-01-01

    Based on a four-month experimental study of preschool children's play with creative-construction and social-fantasy toys, the author examines the in?uence of both types of toys on the play of preschool children. Her comparative analysis considers the impact of transformative play on the development of imagination during play activities and…

  19. Playing My Heart Out: Original Play as Adventure.

    ERIC Educational Resources Information Center

    Donaldson, O. Fred

    1999-01-01

    "Original" play denotes play that is pre-cultural--before conceptualizations and learned responses. Four anecdotes about play with an infant with Down's syndrome, a child with leukemia, a lioness, and a dying woman illustrate the connections between beings and between the ordinary and the sacred during trusting, fearless, playful encounters. (SV)

  20. Facilitation of Play Behavior from Associative to Cooperative Play Stages.

    ERIC Educational Resources Information Center

    Lounsbury, Karen Rasmussen; Bell, Corinne Reed

    An experimental investigation of the transition from associative play to cooperative play was conducted to determine if cooperative play in young children could be facilitated by (1) presenting a toy that required cooperative responses to make it operate, and (2) instructing the children in the use of the toy prior to having them play with it. A…

  1. The effect of gamma irradiation on injectable human amnion collagen

    SciTech Connect

    Liu, B.C.; Harrell, R.; Davis, R.H.; Dresden, M.H.; Spira, M. )

    1989-08-01

    The effect of gamma irradiation on the physicochemical properties of injectable human amnion collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the physical characteristics of the collagen. The neutral solubility of collagen in PBS at 45{degrees}C was decreased from 100% for the nonirradiated control sample to 16% for the 2.5 Mrads irradiated sample. SDS polyacrylamide gel electrophoresis also demonstrated the dose-dependent effect of gamma irradiation on collagen cross-links. Electron microscopic observation revealed that even at low irradiation dose (0.25 Mrads), collagen fibril diameter increased. The average diameter was 50 nm for nonirradiated control fibrils, while 4.4% of the irradiated collagen fibrils had a diameter greater than 100 nm. Irradiated collagen showed little evidence of damage. Well-preserved cross-striations were found in collagen fibrils at all doses of irradiation. Native amnion collagen irradiated with gamma rays demonstrated a slight increase in resistance to collagenase degradation compared with nonirradiated native collagen samples. Increased resistance to collagenase did not correlate with increasing irradiation dose. After 30 min of incubation at 37{degrees}C, both irradiated and nonirradiated collagen was completely digested by collagenase. However, gamma-irradiated collagen did become more sensitive to hydrolysis by trypsin. The higher the irradiation doses used, the greater sensitivity to trypsin was observed. At 0.25 Mrads irradiation only a slight increase was found. No marked differences in amino acid composition were noted among the high dose irradiated, low dose irradiated and control amnion collagen.

  2. Leptin plays a catabolic role on articular cartilage.

    PubMed

    Bao, Jia-peng; Chen, Wei-ping; Feng, Jie; Hu, Peng-fei; Shi, Zhong-li; Wu, Li-dong

    2010-10-01

    Leptin has been shown to play a crucial role in the regulation of body weight. There is also evidence that this adipokine plays a key role in the process of osteoarthritis. However, the precise role of leptin on articular cartilage metabolism is not clear. We investigate the role of leptin on articular cartilage in vivo in this study. Recombinant rat leptin (100 μg) was injected into the knee joints of rats, 48 h later, messenger RNA (mRNA) expression and protein levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), cathepsin D, and collagen II from articular cartilage were analyzed by real-time quantitative polymerase chain reaction (PCR) and western blot. Two important aggrecanases ADAMTS-4 and -5 (a disintegrin and metalloproteinase with thrombospondin motifs 4 and 5) were also analyzed by real-time quantitative PCR. Besides, articular cartilage was also assessed for proteoglycan/GAG content by Safranin O staining. Leptin significantly increased both gene and protein levels of MMP-2, MMP-9, cathepsin D, and collagen II, while decreased bFGF markedly in cartilage. Moreover, the gene expression of ADAMTS-4 and -5 were markedly increased, and histologically assessed depletion of proteoglycan in articular cartilage was observed after treatment with leptin. These results strongly suggest that leptin plays a catabolic role on cartilage metabolism and may be a disadvantage factor involve in the pathological process of OA. PMID:19876764

  3. Aza-Glycine Induces Collagen Hyperstability.

    PubMed

    Zhang, Yitao; Malamakal, Roy M; Chenoweth, David M

    2015-10-01

    Hydrogen bonding is fundamental to life on our planet, and nature utilizes H-bonding in nearly all biomolecular interactions. Often, H-bonding is already maximized in natural biopolymer systems such as nucleic acids, where Watson-Crick H-bonds are fully paired in double-helical structures. Synthetic chemistry allows molecular editing of biopolymers beyond nature's capability. Here we demonstrate that substitution of glycine (Gly) with aza-glycine in collagen may increase the number of interfacial cross-strand H-bonds, leading to hyperstability in the triple-helical form. Gly is the only amino acid that has remained intolerant to substitution in collagen. Our results highlight the vital importance of maximizing H-bonding in higher order biopolymer systems using minimally perturbing alternatives to nature's building blocks. PMID:26368649

  4. Strain stiffening in collagen I networks.

    PubMed

    Motte, Stéphanie; Kaufman, Laura J

    2013-01-01

    Biopolymer gels exhibit strain stiffening that is generally not seen in synthetic gels. Here, we investigate the strain-stiffening behavior in collagen I gels that demonstrate elasticity derived from a variety of sources including crosslinking through telopeptides, bundling through low-temperature gelation, and exogenous crosslinking with genipin. In all cases, it is found that these gels exhibit strain stiffening; in general, onset of strain stiffening occurs earlier, yield strain is lower, and degree of strain stiffening is smaller in higher concentration gels and in those displaying thick fibril bundles. Recovery after exposure to high strains is substantial and similar in all gels, suggesting that much of the stiffening comes from reversible network deformations. A key finding of this study is that collagen I gels of identical storage and loss moduli may display different nonlinear responses and different capacities to recover from high strain. PMID:23097228

  5. About collagen, a tribute to Yves Bouligand

    PubMed Central

    Charvolin, Jean; Sadoc, Jean-François

    2012-01-01

    Yves Bouligand's analysis of the organizations of biological materials in relation to those of liquid crystals enabled the development of the idea that physical forces exerting their actions under strong spatial constraints determine the structures and morphologies of these materials. The different levels of organization in collagen have preoccupied him for a long time. We present here our recent works in this domain that we were still discussing with him a few months before his death at the age of 76 on 21 January 2011. After recalling the hierarchical set of structures built by collagen molecules, we analyse them, exploiting the properties of the curved space of the hypersphere and of the algorithm of phyllotaxis. Those two geometrical concepts can be proposed as structural archetypes founding the polymorphism of this complex material of biological origin. PMID:24098840

  6. About collagen, a tribute to Yves Bouligand.

    PubMed

    Charvolin, Jean; Sadoc, Jean-François

    2012-10-01

    Yves Bouligand's analysis of the organizations of biological materials in relation to those of liquid crystals enabled the development of the idea that physical forces exerting their actions under strong spatial constraints determine the structures and morphologies of these materials. The different levels of organization in collagen have preoccupied him for a long time. We present here our recent works in this domain that we were still discussing with him a few months before his death at the age of 76 on 21 January 2011. After recalling the hierarchical set of structures built by collagen molecules, we analyse them, exploiting the properties of the curved space of the hypersphere and of the algorithm of phyllotaxis. Those two geometrical concepts can be proposed as structural archetypes founding the polymorphism of this complex material of biological origin. PMID:24098840

  7. Study of Native Type I Collagen Fibrils

    NASA Astrophysics Data System (ADS)

    Heim, August

    2006-03-01

    Presented in this work is direct imaging and force microscopy of native, intact type I collagen fibrils extracted from the sea cucumber Cucumaria frondosa dermis with affiliated proteoglycan molecules. The prototypical collagen fibril structure is well conserved through higher mammalian species and presents a model for study of the mechanical properties of the primary individual components of the dermis and skeletal ligature. Common practice is to use reconstituted fibrils which lack the precise conformal structure and affiliated proteoglycans. We have performed force microscopy to probe the mechanical properties of native fibrils and extract the elastic modulus under natural conditions. This knowledge is combined transmission and atomic force imaging, in conjunction with applied computation models, to demonstrate an inherent semitubular structure of these fibrils.

  8. Urinary polypeptides related to collagen synthesis

    PubMed Central

    Krane, Stephen M.; Muñoz, Alberto J.; Harris, Edward D.

    1970-01-01

    Of the total urinary hydroxyproline in normal subjects and those with skeletal disorders, between 4 and 20% was nondialyzable. In some patients with Paget's disease of bone, hyperparathyroidism with osteitis fibrosa, hyperphosphatasia, and extensive fibrous dysplasia the total urinary hydroxyproline was sufficiently high to permit purification of this polypeptide hydroxyproline by gel filtration and ion exchange chromatography. The partially purified polypeptides had molecular weights between 4500 and 10,000 and amino acid compositions and physical properties resembling those of gelatin. The polypeptide fractions also contained neutral sugar and glucosamine. These fragments had been shown to be susceptible to cleavage by purified bacterial collagenase suggesting the presence of the sequence-Pro-X-Gly-Pro-Y-. After administration of proline-14C to patients with Paget's disease hydroxyproline-14C was excreted in the urine. The hydroxyproline-14C specific activity reached a peak in 2-4 hr and declined rapidly. The specific activity of the polypeptide (retentate) portion was severalfold greater than that of the raw urine and diffusate. When the labeled urines were subjected to gel filtration the hydroxyproline-14C fractions of highest molecular weight which were eluted first from the columns had the highest specific activities. Exposure of the hydroxyproline-14C-containing polypeptides to bacterial collagenase rendered them dialyzable. Four patients with hyperparathyroidism and osteitis fibrosa were studied before and after removal of a parathyroid adenoma, a period of transition from a predominance of bone collagen resorption to one of relatively increased bone collagen synthesis. The total urinary hydroxyproline fell rapidly after operation whereas the ratio of the polypeptide fraction to the total rose three- to fourfold. The results of these studies suggest that the urinary polypeptides represent fragments of collagen related to collagen synthesis. Changes in the

  9. Lysine post-translational modifications of collagen

    PubMed Central

    Yamauchi, Mitsuo; Sricholpech, Marnisa

    2012-01-01

    Type I collagen is the most abundant structural protein in vertebrates. It is a heterotrimeric molecule composed of two α1 chains and one α2 chain, forming a long uninterrupted triple helical structure with short non-triple helical telopeptides at both the N- and C-termini. During biosynthesis, collagen acquires a number of post-translational modifications, including lysine modifications, that are critical to the structure and biological functions of this protein. Lysine modifications of collagen are highly complicated sequential processes catalysed by several groups of enzymes leading to the final step of biosynthesis, covalent intermolecular cross-linking. In the cell, specific lysine residues are hydroxylated to form hydroxylysine. Then specific hydroxylysine residues located in the helical domain of the molecule are glycosylated by the addition of galactose or glucose-galactose. Outside the cell, lysine and hydroxylysine residues in the N- and C-telopeptides can be oxidatively deaminated to produce reactive aldehydes that undergo a series of non-enzymatic condensation reactions to form covalent intra- and inter-molecular cross-links. Owing to the recent advances in molecular and cellular biology, and analytical technologies, the biological significance and molecular mechanisms of these modifications have been gradually elucidated. This chapter provides an overview on these enzymatic lysine modifications and subsequent cross-linking. PMID:22708567

  10. Viscoelastic Properties of Isolated Collagen Fibrils

    PubMed Central

    Shen, Zhilei Liu; Kahn, Harold; Ballarini, Roberto; Eppell, Steven J.

    2011-01-01

    Understanding the viscoelastic behavior of collagenous tissues with complex hierarchical structures requires knowledge of the properties at each structural level. Whole tissues have been studied extensively, but less is known about the mechanical behavior at the submicron, fibrillar level. Using a microelectromechanical systems platform, in vitro coupled creep and stress relaxation tests were performed on collagen fibrils isolated from the sea cucumber dermis. Stress-strain-time data indicate that isolated fibrils exhibit viscoelastic behavior that could be fitted using the Maxwell-Weichert model. The fibrils showed an elastic modulus of 123 ± 46 MPa. The time-dependent behavior was well fit using the two-time-constant Maxwell-Weichert model with a fast time response of 7 ± 2 s and a slow time response of 102 ± 5 s. The fibrillar relaxation time was smaller than literature values for tissue-level relaxation time, suggesting that tissue relaxation is dominated by noncollagenous components (e.g., proteoglycans). Each specimen was tested three times, and the only statistically significant difference found was that the elastic modulus is larger in the first test than in the subsequent two tests, indicating that viscous properties of collagen fibrils are not sensitive to the history of previous tests. PMID:21689535

  11. FIBROBLAST MECHANICS IN 3D COLLAGEN MATRICES

    PubMed Central

    Rhee, Sangmyung; Grinnell, Frederick

    2007-01-01

    Connective tissues provide mechanical support and frameworks for the other tissues of the body. Type 1 collagen is the major protein component of ordinary connective tissue, and fibroblasts are the cell type primarily responsible for its biosynthesis and remodeling. Research on fibroblasts interacting with collagen matrices explores all four quadrants of cell mechanics: pro-migratory vs. pro-contractile growth factor environments on one axis; high tension vs. low tension cell-matrix interactions on the other. The dendritic fibroblast – probably equivalent to the resting tissue fibroblast – can be observed only in the low tension quadrant and generally has not been appreciated from research on cells incubated with planar culture surfaces. Fibroblasts in the low tension quadrant require microtubules for formation of dendritic extensions, whereas fibroblasts in the high tension quadrant require microtubules for polarization but not for spreading. Ruffling of dendritic extensions rather than their overall protrusion or retraction provides the mechanism for remodeling of floating collagen matrices, and floating matrix remodeling likely reflects a model of tissue mechanical homeostasis. PMID:17825456

  12. Biomimetic collagen scaffolds with anisotropic pore architecture.

    PubMed

    Davidenko, N; Gibb, T; Schuster, C; Best, S M; Campbell, J J; Watson, C J; Cameron, R E

    2012-02-01

    Sponge-like matrices with a specific three-dimensional structural design resembling the actual extracellular matrix of a particular tissue show significant potential for the regeneration and repair of a broad range of damaged anisotropic tissues. The manipulation of the structure of collagen scaffolds using a freeze-drying technique was explored in this work as an intrinsically biocompatible way of tailoring the inner architecture of the scaffold. The research focused on the influence of temperature gradients, imposed during the phase of crystallisation of collagen suspensions, upon the degree of anisotropy in the microstructures of the scaffolds produced. Moulding technology was employed to achieve differences in heat transfer rates during the freezing processes. For this purpose various moulds with different configurations were developed with a view to producing uniaxial and multi-directional temperature gradients across the sample during this process. Scanning electron microscopy analysis of different cross-sections (longitudinal and horizontal) of scaffolds revealed that highly aligned matrices with axially directed pore architectures were obtained where single unidirectional temperature gradients were induced. Altering the freezing conditions by the introduction of multiple temperature gradients allowed collagen scaffolds to be produced with complex pore orientations, and anisotropy in pore size and alignment. PMID:22005330

  13. Playful Learning and Montessori Education

    ERIC Educational Resources Information Center

    Lillard, Angeline S.

    2013-01-01

    Although Montessori education is often considered a form of playful learning, Maria Montessori herself spoke negatively about a major component of playful learning--pretend play, or fantasy--for young children. In this essay, the author discusses this apparent contradiction: how and why Montessori education includes elements of playful learning…

  14. The Child's Right To Play.

    ERIC Educational Resources Information Center

    Morris, Beverley

    This paper argues that play is an important and fundamental educational process and that the child's right to play should be respected. The paper also comments on the 1990 Tokyo International Conference on the Child's Right to Play. Several issues related to children's play, both in and out of school, are discussed. The focus is on the state of…

  15. Music Learning and Child's Play.

    ERIC Educational Resources Information Center

    Littleton, Danette

    1998-01-01

    Reviews various studies on childs play and its relation to young childrens development in music learning processes and explores the role that cognitive and social play categories have in studying childrens play with music. Provides strategies for initiating music-play opportunities in a preschool classroom. (CMK)

  16. Play and Positive Group Dynamics

    ERIC Educational Resources Information Center

    Thompson, Pam; White, Samantha

    2010-01-01

    Play is an important part of a child's life and essential to learning and development (Vygotsky, 1978). It is vital that students participate in play and that play be conducted in a restorative manner. Play allows a variety of group dynamics to emerge. Irvin Yalom (1995) identifies 11 curative factors of the group experience. These factors include…

  17. Enhanced osteoblast proliferation and collagen gene expression by estradiol

    SciTech Connect

    Ernest, M.; Schmid, Ch.; Froesch, E.R. )

    1988-04-01

    Estrogens play a crucial role in the development of postmenopausal osteoporosis. However, the mechanism by which estrogens exert their effects on bone is unknown. To examine possible direct effects of 17{beta}-estradiol on bone-forming cells, the authors used pure rat osteoblast-like cells in vitro as a model. Osteoblast-like cells prepared from calvaria of newborn rats were cultured serum-free in methylcellulose-containing medium for 21 days. Osteoblast-like cells proliferate selectively into clonally derived cell clusters of spherical morphorlogy. 17{beta}-Estradiol at concentrations of 0.1 nM and 1 nM enhanced osteoblast-like cell proliferation by 41% and 68% above vehicle-treated controls. The biologically inactive stereoisomer 17{alpha}-estradiol (same concentrations) had no effect. Moreover, the antiestrogen tamoxifen abolished the stimulation of osteoblast-like cell proliferation by 17{beta}-estradiol. After 21 days of culture, RNA was prepared and analyzed in a dot-hybridization assay for the abundance of pro{alpha}1(I) collagen mRNA. Steady-state mRNA levels were increased in cultures treated with 17{beta}-estradiol in a dose-dependent manner with maximal stimulation at 1 nM and 10 nM. At the same concentrations, the percentage of synthesized protein (labeled by ({sup 3}H)proline pulse) that was digestible by collagenase was increased, indicating that 17{beta}-estradiol acts as pretranslational levels to enhance synthesis of bone collagen. These data show that the osteoblast is a direct target for 17{beta}-estradiol.

  18. In vivo determination of arterial collagen synthesis in atherosclerotic rabbits

    SciTech Connect

    Opsahl, W.P.; DeLuca, D.J.; Ehrhart, L.A.

    1986-03-01

    Collagen and non-collagen protein synthesis rates were determined in vivo in tissues from rabbits fed a control or atherogenic diet supplemented with 2% peanut oil and 0.25% cholesterol for 4 months. Rabbits received a bolus intravenous injection of L-(/sup 3/H)-proline (1.0 mCi/kg) and unlabeled L-proline (7 mmoles/kg) in 0.9% NaCl. Plasma proline specific activity decreased only 20% over 5 hr and was similar to the specific activity of free proline in tissues. Thoracic aortas from atherosclerotic rabbits exhibited raised plaques covering at least 75% of the surface. Thoracic intima plus a portion of the media (TIM) was separated from the remaining media plus adventitia (TMA). Dry delipidated weight, total collagen content, and collagen as a percent of dry weight were increased significantly in the TIM of atherosclerotic rabbits. Collagen synthesis rates and collagen synthesis as a percent of total protein synthesis were likewise increased both in the TIM and in the abdominal aortas. No differences from controls either in collagen content or collagen synthesis rates were observed in the TMA, lung or skin. These results demonstrate for the first time in vivo that formation of atherosclerotic plaques is associated with increased rates of collagen synthesis. Furthermore, as previously observed with incubations in vitro, collagen synthesis was elevated to a greater extent than noncollagen protein synthesis in atherosclerotic aortas from rabbits fed cholesterol plus peanut oil.

  19. Collagen fibrils as skeletal frame in monkey trabecular meshwork.

    PubMed

    Nishida, S; Mizutani, S

    1994-01-01

    In an attempt to identify the characteristic skeletal frame of the trabecular meshwork, the three-dimensional architecture of collagen fibrillar bundles (collagen bundles) was studied by applying the NaOH cell-maceration method to the anterior segment of cynomolgus monkey eyes. Collagen bundles in the trabecular meshwork were found to be continuous with thinner collagen lamellae in the peripheral cornea and with the collagen fibril plexus in the ciliary body. The collagen core in the uveal cord was columnar in shape and was arranged parallel to the long axis. Collagen bundles were arranged as the layered network forming the fundamental framework of the trabecular meshwork. Most collagen bundles of the corneoscleral sheet were arranged circularly, parallel to the circumference of the limbus, and numerous slender bundles were observed side by side, forming the flat and membranous configuration of the sheet. The endothelial meshwork consisted of a network of fine and sparse collagen fibrils forming extracellular spaces and intercommunicating openings. The inner wall of the canal of Schlemm was seen as a netlike surface of sparse collagen fibrils with variously sized circular openings. The openings suggested the possibility that development of giant vacuoles corresponds to the circular openings under the inner endothelial cell lining. PMID:7933694

  20. Physicochemical properties of collagen solutions cross-linked by glutaraldehyde.

    PubMed

    Tian, Zhenhua; Li, Conghu; Duan, Lian; Li, Guoying

    2014-06-01

    The physicochemical properties of collagen solutions (5 mg/ml) cross-linked by various amounts of glutaraldehyde (GTA) [GTA/collagen (w/w) = 0-0.5] under acidic condition (pH 4.00) were examined. Based on the results of the determination of residual amino group content, sodium dodecyl sulphate-polyacrylamide gel electrophoresis, dynamic rheological measurements, differential scanning calorimetry and atomic force microscopy (AFM), it was proved that the collagen solutions possessed strikingly different physicochemical properties depending on the amount of GTA. At low GTA amounts [GTA/collagen (w/w) ≤ 0.1], the residual amino group contents of the cross-linked collagens decreased largely from 100% to 32.76%, accompanied by an increase in the molecular weight. Additionally, increases of the fiber diameter and the values of G', G″ and η* were measured, while the thermal denaturation temperature (Td) did not change visibly and the fluidity of collagen samples was still retained with increasing the GTA amount. When the ratio of GTA to collagen exceeded 0.1, although the residual amino group content only decreased by ~8.2%, the cross-linked collagen solution [GTA/collagen (w/w) = 0.3] displayed a clear loss of flow and a sudden rise (~2.0 °C) of the Td value compared to the uncross-linked collagen solution, probably illustrating that the collagen solution was converted into a gel with mature network structure-containing nuclei observed in AFM image. It was conjectured that the physicochemical properties of the collagen solutions might be in connection with the cross-linking between collagen molecules from the same aggregate or different aggregates. PMID:24564765

  1. Hyaluronan in aged collagen matrix increases prostate epithelial cell proliferation

    PubMed Central

    Damodarasamy, Mamatha; Vernon, Robert B.; Chan, Christina K.; Plymate, Stephen R.; Wight, Thomas N.

    2015-01-01

    The extracellular matrix (ECM) of the prostate, which is comprised primarily of collagen, becomes increasingly disorganized with age, a property that may influence the development of hyperplasia and cancer. Collageous ECM extracted from the tails of aged mice exhibits many characteristics of collagen in aged tissues, including the prostate. When polymerized into a 3-dimensional (3D) gel, these collagen extracts can serve as models for the study of specific cell-ECM interactions. In the present study, we examined the behaviors of human prostatic epithelial cell lines representing normal prostate epithelial cells (PEC), benign prostatic hyperplasia (BPH-1), and adenocarcinoma (LNCaP) cultured in contact with 3D gels made from collagen extracts of young and aged mice. We found that proliferation of PEC, BPH-1, and LNCaP cells were all increased by culture on aged collagen gels relative to young collagen gels. In examining age-associated differences in the composition of the collagen extracts, we found that aged and young collagen had a similar amount of several collagen-associated ECM components, but aged collagen had a much greater content of the glycosaminoglycan hyaluronan (HA) than young collagen. The addition of HA (of similar size and concentration to that found in aged collagen extracts) to cells placed in young collagen elicited significantly increased proliferation in BPH-1 cells, but not in PEC or LNCaP cells, relative to controls not exposed to HA. Of note, histochemical analyses of human prostatic tissues showed significantly higher expression of HA in BPH and prostate cancer stroma relative to stroma of normal prostate. Collectively, these results suggest that changes in ECM involving increased levels of HA contribute to the growth of prostatic epithelium with aging. PMID:25124870

  2. Collagen VI regulates pericellular matrix properties, chondrocyte swelling, and mechanotransduction in articular cartilage

    PubMed Central

    Zelenski, Nicole A.; Leddy, Holly A.; Sanchez-Adams, Johannah; Zhang, Jinzi; Bonaldo, Paolo; Liedtke, Wolfgang; Guilak, Farshid

    2015-01-01

    Objective Mechanical factors play a critical role in the physiology and pathology of articular cartilage, although the mechanisms of mechanical signal transduction are not fully understood. We examined the hypothesis that type VI collagen is necessary for mechanotransduction in articular cartilage, by determining the effects of type VI collagen knockout on the activation of the mechano-osmosensitive calcium-permeable channel, transient receptor potential vanilloid 4 (TRPV4), osmotically-induced chondrocyte swelling, and pericellular matrix (PCM) mechanical properties. Methods Confocal laser scanning microscopy was used to image TRPV4-mediated calcium signaling and osmotically-induced cell swelling in intact femora from 2 and 9 month old wild type (WT) and type VI collagen deficient (Col6a1−/−) mice. Immunofluorescence-guided atomic force microscopy was used to map PCM mechanical properties based on the presence of perlecan. Results Hypo-osmotic stress induced TRPV4-mediated calcium signaling was increased in Col6a1−/− mice relative to WT controls at 2 months. Col6a1−/− mice exhibited significantly increased osmotically-induced cell swelling and decreased PCM moduli relative to WT controls at both ages. Conclusion In contrast to our original hypothesis, type VI collagen was not required for TRPV4-mediated Ca2+ signaling; however, knockout of type VI collagen altered the mechanical properties of the PCM, which in turn increased the extent of cell swelling and osmotically-induced TRPV4 signaling in an age-dependent manner. These findings emphasize the role of the PCM as a transducer of mechanical and physicochemical signals, and suggest that alterations in PCM properties, as may occur with aging or osteoarthritis, can influence mechanotransduction via TRPV4 or other ion channels. PMID:25604429

  3. Aromatic Interactions Promote Self-association of Collagen Triple-helical Peptides to Higher Order Structures

    PubMed Central

    Kar, Karunakar; Ibrar, Sajjad; Nanda, Vikas; Getz, Todd M.; Kunapuli, Satya P.; Brodsky, Barbara

    2009-01-01

    Aromatic residues are relatively rare within the collagen triple-helix, but they appear to play a specialized role in higher order structure and function. The role of aromatic amino acids in the self-assembly of triple-helical peptides was investigated in terms of the kinetics of self-association, the nature of aggregated species formed, and the ability of these species to activate platelet aggregation. The presence of aromatic residues on both ends of a type IV collagen model peptide is observed to greatly accelerate the kinetics of self-association, decreasing the lag time and leading to insoluble, well defined linear fibrils as well as small soluble aggregates. Both macroscopic visible aggregates and small multi-molecular complexes in solution are capable of inducing platelet aggregation through the glycoprotein VI receptor on platelets. Proline-aromatic CH⋯π interactions are often observed within globular proteins and in protein complexes, and examination of molecular packing in the crystal structure of the integrin binding collagen peptide shows Phe interacts with Pro/Hyp in a neighboring triple-helical molecule. An intermolecular interaction between aromatic amino acids and imino acids within the triple-helix is also supported by the observed inhibitory effect of isolated Phe amino acids on the self-association of (Pro-Hyp-Gly)10. Given the high fraction of Pro and Hyp residues on the surface of collagen molecules, it is likely that imino acid-aromatic CH⋯π interactions are important in formation of higher order structure. It is suggested that the catalysis of type I collagen fibrillogenesis by non-helical telopeptides is due to specific intermolecular CH⋯π interactions between aromatic residues in the telopeptides and Pro/Hyp residues within the triple-helix. PMID:19610672

  4. Effects of jump training on procollagen alpha(1)(i) mRNA expression and its relationship with muscle collagen concentration.

    PubMed

    Ducomps, Christophe; Larrouy, Dominique; Mairal, Aline; Doutreloux, Jean-Paul; Lebas, Francois; Mauriege, Pascale

    2004-04-01

    The aim of this study was to examine the effects of a prolonged high-intensity exercise, jumping, on procollagen alpha(1)(I) mRNA level and collagen concentration in different muscles of trained (T) and control (C) rabbits. Procollagen alpha(1)(I) mRNA expression was much higher (2.8 to 23.5 times) in semimembranosus proprius (SMP), a slow-twitch oxidative muscle, than in extensor digitorum longus (EDL), rectus femoris (RF), and psoas major (Psoas) muscles, both fast-twitch mixed and glycolytic, whatever group was considered (p < 0.001). Procollagen alpha(1)(I) mRNA level also decreased significantly between 50 and 140 days in all muscles (0.001< p < 0.01). However, mRNA levels were 16 to 97% greater at 140 days in all muscles of T animals compared to C ones (0.01< p <0.05). Collagen concentrations of EDL and RF muscles were also higher (14 to 19%) in T than in C rabbits at 90 and 140 days (0.001 < p < 0.05). In the whole sample, collagen concentration was negatively associated with the procollagen alpha(1)(I) mRNA level in EDL and RF muscles (- 0.49 < r < (- 0.44, p < 0.05), while being positively related to mRNA expression in SMP and Psoas muscles (0.65 < r < 0.85, p < 0.01). It is concluded that jump training clearly restricts the decrease of procollagen (I) mRNA level and probably affects collagen synthesis level. In trained rabbit muscles, the maintenance of a better synthesis level could partly explain the higher collagen concentrations found in EDL and RF at 140 days. Nevertheless, the collagen degradation process seems to play the main role in the increase of total collagen concentration with age in EDL and RF muscles. PMID:15064425

  5. Streptococcus gordonii collagen-binding domain protein CbdA may enhance bacterial survival in instrumented root canals ex vivo

    PubMed Central

    Moses, Peter J.; Power, Daniel A.; Jesionowski, Amy M.; Jenkinson, Howard F.; Pantera, Eugene A.; Vickerman, M. Margaret

    2012-01-01

    Introduction The surface-associated collagen-binding protein Ace of Enterococcus faecalis has been implicated as a virulence factor that contributes to bacterial persistence in endodontic infections. The purpose of this study was to determine if proteins with amino acid sequence similarity to Ace found in more abundant oral streptococci could play a similar role in potentially enhancing endodontic infections. Methods A Streptococcus gordonii gene similar to ace was identified by genome sequence searches in silico. An isogenic derivative of strain DL1 with a disruption in the identified gene was constructed by allelic replacement. Parent and mutant strains were characterized for their ability to bind immobilized collagen type-1 in a microtiter plate binding assay. Survival of the strains in a human tooth ex vivo instrumented root canal model was compared by inoculating canals with parental or mutant bacteria and determining the CFUs recovered at various time points over a 12-day period. Results The S. gordonii gene, encoding a protein with a conserved collagen-binding domain similar to that of Ace, was designated cbdA. The cbdA-deficient cells were less able to bind collagen type-1 than parental cells (P <0.0001). Genetic complementation of the cbdA-deficient strain restored the collagen-binding phenotype. By day 12 significantly fewer (P =0.03) cbdA-deficient than parental CFUs were recovered from instrumented canals. Conclusion A gene encoding a putative collagen-binding protein was identified in S. gordonii. Fewer S. gordonii cbdA-deficient cells survived ex vivo compared with parental cells, suggesting that collagen-binding proteins may contribute to persistence of oral streptococci in instrumented root canals. PMID:23228255

  6. Inhibition of Ovarian Tumor Growth by Targeting the HU177 Cryptic Collagen Epitope.

    PubMed

    Caron, Jennifer M; Ames, Jacquelyn J; Contois, Liangru; Liebes, Leonard; Friesel, Robert; Muggia, Franco; Vary, Calvin P H; Oxburgh, Leif; Brooks, Peter C

    2016-06-01

    Evidence suggests that stromal cells play critical roles in tumor growth. Uncovering new mechanisms that control stromal cell behavior and their accumulation within tumors may lead to development of more effective treatments. We provide evidence that the HU177 cryptic collagen epitope is selectively generated within human ovarian carcinomas and this collagen epitope plays a role in SKOV-3 ovarian tumor growth in vivo. The ability of the HU177 epitope to regulate SKOV-3 tumor growth depends in part on its ability to modulate stromal cell behavior because targeting this epitope inhibited angiogenesis and, surprisingly, the accumulation of α-smooth muscle actin-expressing stromal cells. Integrin α10β1 can serve as a receptor for the HU177 epitope in α-smooth muscle actin-expressing stromal cells and subsequently regulates Erk-dependent migration. These findings are consistent with a mechanism by which the generation of the HU177 collagen epitope provides a previously unrecognized α10β1 ligand that selectively governs angiogenesis and the accumulation of stromal cells, which in turn secrete protumorigenic factors that contribute to ovarian tumor growth. Our findings provide a new mechanistic understanding into the roles by which the HU177 epitope regulates ovarian tumor growth and provide new insight into the clinical results from a phase 1 human clinical study of the monoclonal antibody D93/TRC093 in patients with advanced malignant tumors. PMID:27216148

  7. Type III Collagen Directs Stromal Organization and Limits Metastasis in a Murine Model of Breast Cancer

    PubMed Central

    Brisson, Becky K.; Mauldin, Elizabeth A.; Lei, Weiwei; Vogel, Laurie K.; Power, Ashley M.; Lo, Albert; Dopkin, Derek; Khanna, Chand; Wells, Rebecca G.; Puré, Ellen; Volk, Susan W.

    2016-01-01

    Breast cancer metastasis is the leading cause of cancer-related deaths in women worldwide. Collagen in the tumor microenvironment plays a crucial role in regulating tumor progression. We have shown that type III collagen (Col3), a component of tumor stroma, regulates myofibroblast differentiation and scar formation after cutaneous injury. During the course of these wound-healing studies, we noted that tumors developed at a higher frequency in Col3+/− mice compared to wild-type littermate controls. We, therefore, examined the effect of Col3 deficiency on tumor behavior, using the murine mammary carcinoma cell line 4T1. Notably, tumor volume and pulmonary metastatic burden after orthotopic injection of 4T1 cells were increased in Col3+/− mice compared to Col3+/+ littermates. By using murine (4T1) and human (MDA-MB-231) breast cancer cells grown in Col3-poor and Col3-enriched microenvironments in vitro, we found that several major events of the metastatic process were suppressed by Col3, including adhesion, invasion, and migration. In addition, Col3 deficiency increased proliferation and decreased apoptosis of 4T1 cells both in vitro and in primary tumors in vivo. Mechanistically, Col3 suppresses the procarcinogenic microenvironment by regulating stromal organization, including density and alignment of fibrillar collagen and myofibroblasts. We propose that Col3 plays an important role in the tumor microenvironment by suppressing metastasis-promoting characteristics of the tumor-associated stroma. PMID:25795282

  8. Nanointerfacial strength between non-collagenous protein and collagen fibrils in antler bone

    PubMed Central

    Hang, Fei; Gupta, Himadri S.; Barber, Asa H.

    2014-01-01

    Antler bone displays considerable toughness through the use of a complex nanofibrous structure of mineralized collagen fibrils (MCFs) bound together by non-collagenous proteins (NCPs). While the NCP regions represent a small volume fraction relative to the MCFs, significant surface area is evolved upon failure of the nanointerfaces formed at NCP–collagen fibril boundaries. The mechanical properties of nanointerfaces between the MCFs are investigated directly in this work using an in situ atomic force microscopy technique to pull out individual fibrils from the NCP. Results show that the NCP–fibril interfaces in antler bone are weak, which highlights the propensity for interface failure at the nanoscale in antler bone and extensive fibril pullout observed at antler fracture surfaces. The adhesion between fibrils and NCP is additionally suggested as being rate dependent, with increasing interfacial strength and fracture energy observed when pullout velocity decreases. PMID:24352676

  9. Collagen synthesis and degradation in vivo. Evidence for rapid rates of collagen turnover with extensive degradation of newly synthesized collagen in tissues of the adult rat.

    PubMed

    McAnulty, R J; Laurent, G J

    1987-06-01

    Collagen turnover is now known to occur more rapidly in body tissues than traditionally believed, but the kinetics and mechanisms for degradation are still poorly understood. Here we measure collagen synthesis rates and the proportion of newly synthesized collagen (probably procollagen) which is rapidly degraded, in tissues of the adult rat after injection of [14C]-proline with a large "flooding" dose of unlabelled proline. Incorporation of [14C]-proline into lung, heart, skeletal muscle and skin collagen and its appearance as hydroxy [14C]-proline, free or in small molecular weight moieties, at various times up to one hour, suggested extremely rapid synthesis and degradation for some tissues of the adult rat. Values in heart, lung, skeletal muscle and skin (with the proportion of degradation of newly synthesized collagen shown in parentheses) were 5.2 +/- 0.7%/day (53 +/- 5%), 9.0 +/- 0.7%/day (37 +/- 2%), 2.2 +/- 0.3%/day (38 +/- 7%) and 4.4 +/- 1.3%/day (8.8 +/- 0.5%). These data provide in vivo evidence, which are consistent with the observation in isolated cells, that a proportion of newly synthesized collagen is degraded rapidly, and probably intracellularly, after its synthesis. They also indicate that collagen may be synthesized and degraded rapidly in normal rat tissues, but the mean turnover rates and the proportions of collagen degraded intracellularly vary widely between tissues. PMID:3497767

  10. Alpha 1(XVIII), a collagen chain with frequent interruptions in the collagenous sequence, a distinct tissue distribution, and homology with type XV collagen.

    PubMed Central

    Rehn, M; Pihlajaniemi, T

    1994-01-01

    We report on the isolation of mouse cDNA clones which encode a collagenous sequence designated here as the alpha 1 chain of type XVIII collagen. The overlapping clones cover 2.8 kilobases and encode an open reading frame of 928 amino acid residues comprising a putative signal peptide of 25 residues, an amino-terminal noncollagenous domain of 301 residues, and a primarily collagenous stretch of 602 residues. The clones do not cover the carboxyl-terminal end of the polypeptide, since the translation stop codon is absent. Characteristic of the deduced polypeptide is the possession of eight noncollagenous interruptions varying in length from 10 to 24 residues in the collagenous amino acid sequence. Other features include the presence of several putative sites for both N-linked glycosylation and O-linked glycosaminoglycan attachment and homology of the amino-terminal noncollagenous domain with thrombospondin. It is of particular interest that five of the eight collagenous sequences of type XVIII show homology to the previously reported type XV collagen, suggesting that the two form a distinct subgroup among the diverse family of collagens. Northern blot hybridization analysis revealed a striking tissue distribution for type XVIII collagen mRNAs, as the clones hybridized strongly with mRNAs of 4.3 and 5.3 kilobases that were present only in lung and liver of the eight mouse tissues studied. Images PMID:8183894

  11. Mass transfer of large molecules through collagen and collagen-silica hybrid membranes

    NASA Astrophysics Data System (ADS)

    Jofre-Lora, Pedro

    Diabetes is a growing concern in the United States and around the world that must be addressed through new treatment options. Current standard treatment options of diabetes are limiting and have tremendous impacts on patient's lives. Emerging therapies, such as the implantation of encapsulated islets, are promising treatment options, but have not yet materialized due to unsolved problems with material properties. Hybrid silica-collagen membranes address some of these unsolved problems and are a promising material for cell encapsulation. However, the mass transfer properties of large molecules, such as insulin, TNF-alpha, IL1beta, and other important proteins in the etiology of diabetes, through these hybrid membranes are poorly characterized. In order to begin characterizing these properties, a device was constructed to accurately and efficiently measure the mass transfer of other similar large molecules, fluorescein isothiocyanate dextrans (FITC-dextran), through collagen-silica hybrid membranes. The device was used to measure diffusion coefficients of 4, 20, 40, and 150 kDa FITC-dextrans through non-silicified and silicified samples of 200 and 1000 Pa porcine skin collagen. Diffusion coefficients were found to be in the 10-7-10-6 cm2s -1 range, which is in agreement with previously published data for similar molecules through similar hydrogels. The effects of collagen stiffness, FITC-dextran molecular weight, and silicification treatment on diffusion were investigated. It was found that collagen stiffness and FITC-dextran molecular weight had a negative correlation with diffusion, whereas silicification treatment had no global impact on diffusion. The device created, and the results of this preliminary investigation, can be used to develop collagen-silica hybrid membranes as an alternative material for cell encapsulation in a forward-design manner.

  12. ISOCT study of collagen crosslinking of collagen in cancer models (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Spicer, Graham; Young, Scott T.; Yi, Ji; Shea, Lonnie D.; Backman, Vadim

    2016-03-01

    The role of extracellular matrix modification and signaling in cancer progression is an increasingly recognized avenue for the progression of the disease. Previous study of field effect carcinogenesis with Inverse Spectroscopic Optical Coherence Tomography (ISOCT) has revealed pronounced changes in the nanoscale-sensitive mass fractal dimension D measured from field effect tissue when compared to healthy tissue. However, the origin of this difference in tissue ultrastructure in field effect carcinogenesis has remained poorly understood. Here, we present findings supporting the idea that enzymatic crosslinking of the extracellular matrix is an effect that presents at the earliest stages of carcinogenesis. We use a model of collagen gel with crosslinking induced by lysyl oxidase (LOXL4) to recapitulate the difference in D previously reported from healthy and cancerous tissue biopsies. Furthermore, STORM imaging of this collagen gel model verifies the morphologic effects of enzymatic crosslinking at length scales as small as 40 nm, close to the previously reported lower length scale sensitivity threshold of 35 nm for ISOCT. Analysis of the autocorrelation function from STORM images of collagen gels and subsequent fitting to the Whittle-Matérn correlation function shows a similar effect of LOXL4 on D from collagen measured with ISOCT and STORM. We extend this to mass spectrometric study of tissue to directly measure concentrations of collagen crosslink residues. The validation of ISOCT as a viable tool for non-invasive rapid quantification of collagen ultrastructure lends it to study other physiological phenomena involving ECM restructuring such as atherosclerotic plaque screening or cervical ripening during pregnancy.

  13. Evaluation of the Nature of Collagen Fibers in KCOT, Dentigerous Cyst and Ameloblastoma using Picrosirius Red Stain – A Comparative Study

    PubMed Central

    Sekhar, Manne Srinivas Muni; Shylaja, Sanjeevareddygari; Bhavani, Sangala Nagendra; Ramanand, Oruganti Venkata; Patha, Spandana; Reddy, Sharath Kumar; Rani, Akula Sandhya

    2015-01-01

    Background Reciprocal interaction between dental epithelium and mesenchyme is thought to be crucial for normal odontogenesis. Thus, the mesenchymal influence of the fibrous capsules may play an important role in the maintenance of epithelial expression. Collagen is the major component of the extracellular matrix and possibly there is an alteration in the nature and structure of collagen in various pathological conditions. Studies by polarizing microscopy have also shown that there is a difference in collagen and probably these differences may play a role in their biologic behaviour. Aim The purpose of this study was to evaluate the nature of collagen fibers in keratocystic odontogenic tumour (KCOT), dentigerous cyst (DC), unicystic ameloblastoma (UA) and solid/multicystic ameloblastoma (SMA) and correlating this with their biological behaviour. Materials and Methods Five diagnosed cases each of UA, SMA, KCOT and DC were taken and stained using Picrosirius red stain kit and evaluated using a polarizing microscope. Statistical Analysis Chi-square test was used to analyse the results. Results and Conclusion Collagen fibers in dentigerous cysts showed predominant yellowish-red birefringence and fibers in KCOT and ameloblastomas showed a predominantly greenish-yellow birefringence. Hence, our study suggests that the nature and character of collagen fibers may influence the clinical behaviour of the lesion. Since ours is a pilot study, to corroborate our view, studies with larger sample size are required to substantiate the results. PMID:26673081

  14. Toy Play, Play Tempo, and Reaction to Frustration in Infants.

    ERIC Educational Resources Information Center

    Longo, Josephine; And Others

    1982-01-01

    In two sessions, the duration and tempo of toy play of infants and reaction of frustration were measured. Correlations indicated a general relationship between response persistence during play and attempts to escape frustrating situations. (Author/CM)

  15. Sol-gel assisted fabrication of collagen hydrolysate composite scaffold: a novel therapeutic alternative to the traditional collagen scaffold.

    PubMed

    Ramadass, Satiesh Kumar; Perumal, Sathiamurthi; Gopinath, Arun; Nisal, Anuya; Subramanian, Saravanan; Madhan, Balaraman

    2014-09-10

    Collagen is one of the most widely used biomaterial for various biomedical applications. In this Research Article, we present a novel approach of using collagen hydrolysate, smaller fragments of collagen, as an alternative to traditionally used collagen scaffold. Collagen hydrolysate composite scaffold (CHCS) was fabricated with sol-gel transition procedure using tetraethoxysilane as the silica precursor. CHCS exhibits porous morphology with pore sizes varying between 380 and 780 μm. Incorporation of silica conferred CHCS with controlled biodegradation and better water uptake capacity. Notably, 3T3 fibroblast proliferation was seen to be significantly better under CHCS treatment when compared to treatment with collagen scaffold. Additionally, CHCS showed excellent antimicrobial activity against the wound pathogens Staphylococcus aureus, Bacillus subtilis, and Escherichia coli due to the inherited antimicrobial activity of collagen hydrolysate. In vivo wound healing experiments with full thickness excision wounds in rat model demonstrated that wounds treated with CHCS showed accelerated healing when compared to wounds treated with collagen scaffold. These findings indicate that the CHCS scaffold from collagen fragments would be an effective and affordable alternative to the traditionally used collagen structural biomaterials. PMID:25105509

  16. Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.

    PubMed

    Niu, Li-Na; Jiao, Kai; Qi, Yi-Pin; Nikonov, Sergey; Yiu, Cynthia K Y; Arola, Dwayne D; Gong, Shi-Qiang; El-Marakby, Ahmed; Carrilho, Marcela R O; Hamrick, Mark W; Hargreaves, Kenneth M; Diogenes, Anibal; Chen, Ji-Hua; Pashley, David H; Tay, Franklin R

    2012-11-01

    Traditional bone regeneration strategies relied on supplementation of biomaterials constructs with stem or progenitor cells or growth factors. By contrast, cell homing strategies employ chemokines to mobilize stem or progenitor cells from host bone marrow and tissue niches to injured sites. Although silica-based biomaterials exhibit osteogenic and angiogenic potentials, they lack cell homing capability. Stromal cell-derived factor-1 (SDF-1) plays a pivotal role in mobilization and homing of stem cells to injured tissues. In this work, we demonstrated that 3-dimensional collagen scaffolds infiltrated with intrafibrillar silica are biodegradable and highly biocompatible. They exhibit improved compressive stress-strain responses and toughness over nonsilicified collagen scaffolds. They are osteoconductive and up-regulate expressions of osteogenesis- and angiogenesis-related genes more significantly than nonsilicified collagen scaffolds. In addition, these scaffolds reversibly bind SDF-1α for sustained release of this chemokine, which exhibits in vitro cell homing characteristics. When implanted subcutaneously in an in vivo mouse model, SDF-1α-loaded silicified collagen scaffolds stimulate the formation of ectopic bone and blood capillaries within the scaffold and abrogate the need for cell seeding or supplementation of osteogenic and angiogenic growth factors. Intrafibrillar-silicified collagen scaffolds with sustained SDF-1α release represent a less costly and complex alternative to contemporary cell seeding approaches and provide new therapeutic options for in situ hard tissue regeneration. PMID:22859369

  17. miRNA-29a targets COL3A1 to regulate the level of type III collagen in pig.

    PubMed

    Chuan-Hao, Li; Wei, Chen; Jia-Qing, Hu; Yan-Dong, Wang; Shou-Dong, Wang; Yong-Qing, Zeng; Hui, Wang

    2016-10-30

    COL3A1 encodes the protein, collagen type III alpha 1, which is an important component of collagen. Collagen can have a considerable effect on the processing quality of meat, and is nutritious. Bioinformatic analysis using Targetscan showed that COL3A1 could be a target gene of miRNA-29a. Moreover, we found that Laiwu pigs have higher levels of type III collagen and lower levels of miRNA-29a than Landrace pigs. Therefore, we hypothesized that miRNA-29a suppresses the expression of COL3A1 by targeting its 3'-UTR. miRNA-29a appears to play an inhibitory role in the regulation of COL3A1 in PK15 cells because of the following: (1) overexpression of miRNA-29a resulted in a significant down-regulation of COL3A1 protein levels (2) overexpression of miRNA-29a significantly decreased the level of COL3A1 mRNA. (3) The activity of a COL3A1 luciferase reporter was significant reduced by miRNA-29a. Furthermore, the levels of miRNA-29a and collagen type III in four tissues in Laiwu and Landrace pigs were consistent with the above observations. In this study, we identified COL3A1 as a direct target for miRNA-29a, which will inform further studies of meat quality. PMID:27476968

  18. Increased expression of the collagen internalization receptor uPARAP/Endo180 in the stroma of head and neck cancer.

    PubMed

    Sulek, Jay; Wagenaar-Miller, Rebecca A; Shireman, Jessica; Molinolo, Alfredo; Madsen, Daniel H; Engelholm, Lars H; Behrendt, Niels; Bugge, Thomas H

    2007-04-01

    Local growth, invasion, and metastasis of malignancies of the head and neck involve extensive degradation and remodeling of the underlying, collagen-rich connective tissue. Urokinase plasminogen activator receptor-associated protein (uPARAP)/Endo180 is an endocytic receptor recently shown to play a critical role in the uptake and intracellular degradation of collagen by mesenchymal cells. As a step toward determining the putative function of uPARAP/Endo180 in head and neck cancer progression, we used immunohistochemistry to determine the expression of this collagen internalization receptor in 112 human squamous cell carcinomas and 19 normal or tumor-adjacent head and neck tissue samples from the tongue, gingiva, cheek, tonsils, palate, floor of mouth, larynx, maxillary sinus, upper jaw, nasopharynx/nasal cavity, and lymph nodes. Specificity of detection was verified by staining of serial sections with two different monoclonal antibodies against two non-overlapping epitopes on uPARAP/Endo180 and by the use of isotype-matched non-immune antibodies. uPARAP/Endo180 expression was observed in stromal fibroblast-like, vimentin-positive cells. Furthermore, expression of the collagen internalization receptor was increased in tumor stroma compared with tumor-adjacent connective tissue or normal submucosal connective tissue and was most prominent in poorly differentiated tumors. These data suggest that uPARAP/Endo180 participates in the connective tissue destruction during head and neck squamous cell carcinoma progression by mediating cellular uptake and lysosomal degradation of collagen. PMID:17189524

  19. Effect of mineral-collagen interfacial behavior on the microdamage progression in bone using a probabilistic cohesive finite element model.

    PubMed

    Luo, Qing; Nakade, Rugved; Dong, Xuanliang; Rong, Qiguo; Wang, Xiaodu

    2011-10-01

    The interactions between mineral and collagen phases in the ultrastructural level play an important role in determining the mechanical properties of bone tissue. Three types of mineral-collagen interaction (i.e., ionic interactions, hydrogen/van der Waals bonds, and van der Waals/viscous shear in opening/sliding mode, respectively) have been simulated in this study, using cohesive zone-modeling techniques. Considering the inhomogeneity of bone, a probabilistic failure analysis approach has been also employed to account for the effect of mineral-collagen interfacial behavior on microdamage accumulation in lamellar bone tissues. The results of this study suggested that different interfacial behaviors cause different types of microdamage accumulation. The ionic interactions between the mineral and collagen phases lead to the formation of linear microcracks, while the van der Waals/viscous shear interactions may facilitate the formation of diffuse damage. In the case of hydrogen/van der Waals bonds, a transitional behavior of microdamage accumulation in bone was observed. The findings of this study may help in understanding the mechanisms of mineral-collagen interactions and its effects on the failure mechanism of bone. PMID:21783104

  20. Molecular mechanics and dynamics studies on the interaction of gallic acid with collagen-like peptides

    NASA Astrophysics Data System (ADS)

    Madhan, B.; Thanikaivelan, P.; Subramanian, V.; Raghava Rao, J.; Unni Nair, Balachandran; Ramasami, T.

    2001-10-01

    Molecular modelling approaches have been used to understand the interaction of collagen-like peptides with gallic acid, which mimic vegetable tanning processes involved in protein stabilization. Several interaction sites have been identified and the binding energies of the complexes have been calculated. The calculated binding energies for various geometries are in the range 6-13 kcal/mol. It is found that some complexes exhibit hydrogen bonding, and electrostatic interaction plays a dominant role in the stabilization of the peptide by gallic acid. The π-OH type of interaction is also observed in the peptide stabilization. Molecular dynamics (MD) simulation for 600 ps revealed the possibility of hydrogen bonding between the collagen-like peptide and gallic acid.

  1. Molecular Mechanism of Type I Collagen Homotrimer Resistance to Mammalian Collagenases*

    PubMed Central

    Han, Sejin; Makareeva, Elena; Kuznetsova, Natalia V.; DeRidder, Angela M.; Sutter, Mary Beth; Losert, Wolfgang; Phillips, Charlotte L.; Visse, Robert; Nagase, Hideaki; Leikin, Sergey

    2010-01-01

    Type I collagen cleavage is crucial for tissue remodeling, but its homotrimeric isoform is resistant to all collagenases. The homotrimers occur in fetal tissues, fibrosis, and cancer, where their collagenase resistance may play an important physiological role. To understand the mechanism of this resistance, we studied interactions of α1(I)3 homotrimers and normal α1(I)2α2(I) heterotrimers with fibroblast collagenase (MMP-1). Similar MMP-1 binding to the two isoforms and similar cleavage efficiency of unwound α1(I) and α2(I) chains suggested increased stability and less efficient unwinding of the homotrimer triple helix at the collagenase cleavage site. The unwinding, necessary for placing individual chains inside the catalytic cleft of the enzyme, was the rate-limiting cleavage step for both collagen isoforms. Comparative analysis of the homo- and heterotrimer cleavage kinetics revealed that MMP-1 binding promotes stochastic helix unwinding, resolving the controversy between different models of collagenase action. PMID:20463013

  2. Imaging and modeling collagen architecture from the nano to micro scale

    PubMed Central

    Brown, Cameron P.; Houle, Marie-Andree; Popov, Konstantin; Nicklaus, Mischa; Couture, Charles-Andre; Laliberté, Matthieu; Brabec, Thomas; Ruediger, Andreas; Carr, Andrew J.; Price, Andrew J.; Gill, Harinderjit S.; Ramunno, Lora; Légaré, Francois

    2013-01-01

    The collagen meshwork plays a central role in the functioning of a range of tissues including cartilage, tendon, arteries, skin, bone and ligament. Because of its importance in function, it is of considerable interest for studying development, disease and regeneration processes. Here, we have used second harmonic generation (SHG) to image human tissues on the hundreds of micron scale, and developed a numerical model to quantitatively interpret the images in terms of the underlying collagen structure on the tens to hundreds of nanometer scale. Focusing on osteoarthritic changes in cartilage, we have demonstrated that this combination of polarized SHG imaging and numerical modeling can estimate fibril diameter, filling fraction, orientation and bundling. This extends SHG microscopy from a qualitative to quantitative imaging technique, providing a label-free and non-destructive platform for characterizing the extracellular matrix that can expand our understanding of the structural mechanisms in disease. PMID:24466490

  3. Playing with Switches, Birth through Two. Let's Play! Project.

    ERIC Educational Resources Information Center

    State Univ. of New York, Buffalo. Center for Assistive Technology.

    This guide to playing with switches for parents and early intervention personnel was developed by the "Let's Play! Project," a 3-year federally supported project that worked to promote play in infants and toddlers with disabilities through the use of assistive technology. Switches are used with electronic toys to help young children easily…

  4. Increasing Joint Attention, Play and Language through Peer Supported Play.

    ERIC Educational Resources Information Center

    Zercher, Craig; Hunt, Pam; Schuler, Adriana; Webster, Janice

    2001-01-01

    This study examined effects of participation in an integrated play group on the social skills of two 6-year-old twins with autism. Following intervention with adult coaching, typical peers implemented the play group techniques in weekly play group sessions. The autistic subjects showed dramatic increases in shared attention to objects, symbolic…

  5. Solar Power at Play

    NASA Astrophysics Data System (ADS)

    2007-03-01

    For the very first time, astronomers have witnessed the speeding up of an asteroid's rotation, and have shown that it is due to a theoretical effect predicted but never seen before. The international team of scientists used an armada of telescopes to discover that the asteroid's rotation period currently decreases by 1 millisecond every year, as a consequence of the heating of the asteroid's surface by the Sun. Eventually it may spin faster than any known asteroid in the solar system and even break apart. ESO PR Photo 11a/07 ESO PR Photo 11a/07 Asteroid 2000 PH5 "The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the Solar System rotate," said Stephen Lowry (Queens University Belfast, UK), lead-author of one of the two companion papers in which this work is reported [1, 2]. "The warming caused by sunlight hitting the surfaces of asteroids and meteoroids leads to a gentle recoil effect as the heat is released," he added. "By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning." Although this is an almost immeasurably weak force, its effect over millions of years is far from negligible. Astronomers believe the YORP effect may be responsible for spinning some asteroids up so fast that they break apart, perhaps leading to the formation of double asteroids. Others may be slowed down so that they take many days to complete a full turn. The YORP effect also plays an important role in changing the orbits of asteroids between Mars and Jupiter, including their delivery to planet-crossing orbits, such as those of near-Earth asteroids. Despite its importance, the effect has never been seen acting on a solar system body, until now. Using extensive optical and radar imaging from powerful Earth-based observatories, astronomers have directly observed the YORP effect in action on a small near-Earth asteroid, known as (54509) 2000 PH5. Shortly after its discovery in 2000, it was

  6. Nanorod mediated collagen scaffolds as extra cellular matrix mimics.

    PubMed

    Vedhanayagam, Mohan; Mohan, Ranganathan; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan

    2015-12-01

    Creating collagen scaffolds that mimic extracellular matrices without using toxic exogenous materials remains a big challenge. A new strategy to create scaffolds through end-to-end crosslinking through functionalized nanorods leading to well-designed architecture is presented here. Self-assembled scaffolds with a denaturation temperature of 110 °C, porosity of 70%, pore size of 0.32 μm and Young's modulus of 231 MPa were developed largely driven by imine bonding between 3-mercapto-1-propanal (MPA) functionalized ZnO nanorods and collagen. The mechanical properties obtained were much higher than that of native collagen, collagen-MPA, collagen-3-mercapto-1-propanol (3MPOH) or collagen- 3-MPOH-ZnO, clearly bringing out the relevance of nanorod mediated assembly of fibrous networks. This new strategy has led to scaffolds with mechanical properties much higher than earlier reports and can provide support for cell growth and facilitation of cell attachment. PMID:26586667

  7. Review collagen-based biomaterials for wound healing.

    PubMed

    Chattopadhyay, Sayani; Raines, Ronald T

    2014-08-01

    With its wide distribution in soft and hard connective tissues, collagen is the most abundant of animal proteins. In vitro, natural collagen can be formed into highly organized, three-dimensional scaffolds that are intrinsically biocompatible, biodegradable, nontoxic upon exogenous application, and endowed with high tensile strength. These attributes make collagen the material of choice for wound healing and tissue engineering applications. In this article, we review the structure and molecular interactions of collagen in vivo; the recent use of natural collagen in sponges, injectables, films and membranes, dressings, and skin grafts; and the on-going development of synthetic collagen mimetic peptides as pylons to anchor cytoactive agents in wound beds. PMID:24633807

  8. Amyotrophic lateral sclerosis: increased solubility of skin collagen

    NASA Technical Reports Server (NTRS)

    Ono, S.; Yamauchi, M.

    1992-01-01

    We studied the solubility of skin collagen from six patients with amyotrophic lateral sclerosis (ALS) and six controls. The amount of collagen extracted with neutral salt solution was significantly greater in patients with ALS than in controls. In addition, there was a statistically significant increase in the proportion of collagen extracted from ALS patients with increased duration of illness. The collagen solubilized by pepsin and cyanogen bromide treatments was significantly higher in ALS patients than in controls, and its proportion was positively and significantly associated with duration of illness in ALS patients. These results indicate that the metabolism of skin collagen may be affected in the disease process of ALS, causing an increase in immature soluble collagen in the tissue, which is the opposite to that which occurs in the normal aging process.

  9. Enhancing collagen stability through nanostructures containing chromium(III) oxide.

    PubMed

    Sangeetha, Selvam; Ramamoorthy, Usha; Sreeram, Kalarical Janardhanan; Nair, Balachandran Unni

    2012-12-01

    Stabilization of collagen for various applications employs chemicals such as aldehydes, metal ions, polyphenols, etc. Stability against enzymatic, thermal and mechanical degradation is required for a range of biomedical applications. The premise of this research is to explore the use of nanoparticles with suitable functionalization/encapsulation to crosslink with collagen, such that the three dimensional architecture had the desired stability. Collagen solution prepared as per standard protocols is treated with chromium(III) oxide nanoparticules encapsulated within a polymeric matrix (polystyrene-block-polyacrylic acid copolymer). Selectivity towards encapsulation was ensured by the reaction in dimethyl sulfoxide, where the PS groups popped out and encapsulated the Cr(2)O(3). Subsequently when immersed in aqueous solution, PAA units popped up to react with functional groups of collagen. The interaction with collagen was monitored through techniques such as CD, FTIR, viscosity measurements, stress analysis. CD studies and FTIR showed no degradation of collagen. Thermal stability was enhanced upon interaction of nanostructures with collagen. Self-assembly of collagen was delayed but not inhibited, indicating a compete binding of the metal oxide encapsulated polymer to collagen. Metal oxide nanoparticles encapsulated within a polymeric matrix could provide thermal and mechanical stability to collagen. The formed fibrils of collagen could serve as ideal material for various smart applications such as slow/sustained drug release. The study is also relevant to the leather industry in that the nanostructures can diffuse through the highly networked collagen fibre bundles in skin matrix easily, thus overcoming the rate limiting step of diffusion. PMID:22766281

  10. Collagenous gastritis: a morphologic and immunohistochemical study of 40 patients.

    PubMed

    Arnason, Thomas; Brown, Ian S; Goldsmith, Jeffrey D; Anderson, William; O'Brien, Blake H; Wilson, Claire; Winter, Harland; Lauwers, Gregory Y

    2015-04-01

    Collagenous gastritis is a rare condition defined histologically by a superficial subepithelial collagen layer. This study further characterizes the morphologic spectrum of collagenous gastritis by evaluating a multi-institutional series of 40 patients (26 female and 14 male). The median age at onset was 16 years (range 3-89 years), including 24 patients (60%) under age 18. Twelve patients (30%) had associated celiac disease, collagenous sprue, or collagenous colitis. Hematoxylin and eosin slides were reviewed in biopsies from all patients and tenascin, gastrin, eotaxin, and IgG4/IgG immunohistochemical stains were applied to a subset. The distribution of subepithelial collagen favored the body/fundus in pediatric patients and the antrum in adults. There were increased surface intraepithelial lymphocytes (>25 lymphocytes/100 epithelial cells) in five patients. Three of these patients had associated celiac and/or collagenous sprue/colitis, while the remaining two had increased duodenal lymphocytosis without specific etiology. An eosinophil-rich pattern (>30 eosinophils/high power field) was seen in 21/40 (52%) patients. Seven patients' biopsies demonstrated atrophy of the gastric corpus mucosa. Tenascin immunohistochemistry highlighted the subepithelial collagen in all 21 specimens evaluated and was a more sensitive method of collagen detection in biopsies from two patients with subtle subepithelial collagen. No increased eotaxin expression was identified in 16 specimens evaluated. One of the twenty-three biopsies tested had increased IgG4-positive cells (100/high power field) with an IgG4/IgG ratio of 55%. In summary, collagenous gastritis presents three distinct histologic patterns including a lymphocytic gastritis-like pattern, an eosinophil-rich pattern, and an atrophic pattern. Eotaxin and IgG4 were not elevated enough to implicate these pathways in the pathogenesis. Tenascin immunohistochemistry can be used as a sensitive method of collagen detection. PMID

  11. Learning, Play, and Your Newborn

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Learning, Play, and Your Newborn KidsHealth > For Parents > Learning, ... juega su recién nacido What Is My Newborn Learning? Play is the chief way that infants learn ...

  12. Medical Play for Young Children.

    ERIC Educational Resources Information Center

    Jessee, Peggy O.; Wilson, Heidi; Morgan, Dee

    2000-01-01

    Discusses young children's emotional responses during medical examinations and procedures, developmental changes in how they conceptualize illness causation, and the role of play to reduce stress. Describes how teachers can best facilitate structured dramatic medical play therapeutically. (KB)

  13. Polarized Microscopy in Lesions With Altered Dermal Collagen.

    PubMed

    Elbendary, Amira; Valdebran, Manuel; Parikh, Kruti; Elston, Dirk M

    2016-08-01

    Alterations in dermal collagen are noted in dermatofibroma, dermatofibrosarcoma protuberans, morphea, lichen sclerosus et atrophicus, hypertrophic scars, and keloids. The authors sought to determine whether variations in birefringence of collagen by polarized microscopy could be of help in diagnosing such conditions. Representative hematoxylin and eosin sections of 400 cases, including dermatofibroma, dermatofibrosarcoma protuberans, hypertrophic scars, keloid, morphea, and lichen sclerosus, were examined under polarized microscopy. Distinct patterns of birefringence of collagen for each disease were noted under polarized microscopy. This study highlights the use of polarized microscopy as adjunctive tool in differentiating different diseases with collagen alteration. PMID:26959692

  14. Collagen fibril biosynthesis in tendon: a review and recent insights.

    PubMed

    Canty, E G; Kadler, K E

    2002-12-01

    The development and evolution of multicellular animals relies on the ability of certain cell types to synthesise an extracellular matrix (ECM) comprising very long collagen fibrils that are arranged in very ordered 3-dimensional scaffolds. Tendon is a good example of a highly ordered ECM, in which tens of millions of collagen fibrils, each hundreds of microns long, are synthesised parallel to the tendon long axis. This review highlights recent discoveries showing that the assembly of collagen fibrils in tendon is hierarchical, and involves the formation of fairly short "collagen early fibrils" that are the fusion precursors of the very long fibrils that occur in mature tendon. PMID:12485687

  15. Electrostatic Forces Mediated by Choline Dihydrogen Phosphate Stabilize Collagen.

    PubMed

    Mehta, Ami; Rao, J Raghava; Fathima, N Nishad

    2015-10-01

    Cross-linkers aid in improving biostability of collagen via different mechanisms. Choline dihydrogen phosphate (cDHP), a biocompatible ionic liquid, has been reported as a potential cross-linker for collagen. However, its mechanism is yet unclear. This study explores the effect of cDHP on the physicochemical stability of collagen and nature of its interaction. Dielectric behavior of collagen-cDHP composites signifies that cDHP enhances intermolecular forces. This was demonstrated by an increase in cross-linked groups and high denaturation temperature of collagen-cDHP composites. XRD measurements reveal minor conformational change in helices. Molecular modeling studies illustrate that the force existing between collagen and cDHP is electrostatic in nature. Herein, it is postulated that dihydrogen phosphate anion attaches to cationic functional groups of collagen, resulting in closer vicinity of various side chains of collagen, forming physical and chemical cross-links within collagen, contributing to its structural stability. Our study suggests that dihydrogen phosphate anions can be employed for developing a new class of biocompatible cross-linkers. PMID:26388068

  16. Instability of Polymeric Skin Collagen in Osteogenesis Imperfecta

    PubMed Central

    Francis, M. J. O.; Smith, Roger; Bauze, Robert J.

    1974-01-01

    The structural polymeric collagen of the skin of 19 patients with osteogenesis imperfecta has been examined. In those with severe bone disease, who often have white sclerae, this collagen fraction is less resistant to depolymerization than that of age-matched controls, though the total amount is normal. In patients with less severe bone disease, whose sclerae are usually blue, the polymeric collagen may have normal stability but the total amount is reduced. These results suggest defective cross-linking of collagen in severe osteogenesis imperfecta. PMID:4816854

  17. Circular permutation directs orthogonal assembly in complex collagen peptide mixtures.

    PubMed

    Xu, Fei; Silva, Teresita; Joshi, Mihir; Zahid, Sohail; Nanda, Vikas

    2013-11-01

    Multiple types of natural collagens specifically assemble and co-exist in the extracellular matrix. Although noncollagenous trimerization domains facilitate the folding of triple-helical regions, it is intriguing to ask whether collagen sequences are also capable of controlling heterospecific association. In this study, we designed a model system mimicking simultaneous specific assembly of two collagen heterotrimers using a genetically inspired operation, circular permutation. Previously, surface charge-pair interactions were optimized on three collagen peptides to promote the formation of an abc-type heterotrimer. Circular permutation of these sequences retained networks of stabilizing interactions, preserving both triple-helical structure and heterospecificity of assembly. Combining original peptides A, B, and C and permuted peptides D, E, and F resulted primarily in formation of A:B:C and D:E:F, a heterospecificity of 2 of 56 possible stoichiometries. This degree of specificity in collagen molecular recognition is unprecedented in natural or synthetic collagens. Analysis of natural collagen sequences indicates low similarity between the neighboring exons. Combining the synthetic collagen model and bioinformatic analysis provides insight on how fibrillar collagens might have arisen from the duplication of smaller domains. PMID:24043622

  18. Characterization of the ultrashort-TE (UTE) MR collagen signal.

    PubMed

    Siu, Adrienne G; Ramadeen, Andrew; Hu, Xudong; Morikawa, Lily; Zhang, Li; Lau, Justin Y C; Liu, Garry; Pop, Mihaela; Connelly, Kim A; Dorian, Paul; Wright, Graham A

    2015-10-01

    Although current cardiovascular MR (CMR) techniques for the detection of myocardial fibrosis have shown promise, they nevertheless depend on gadolinium-based contrast agents and are not specific to collagen. In particular, the diagnosis of diffuse myocardial fibrosis, a precursor of heart failure, would benefit from a non-invasive imaging technique that can detect collagen directly. Such a method could potentially replace the need for endomyocardial biopsy, the gold standard for the diagnosis of the disease. The objective of this study was to measure the MR properties of collagen using ultrashort TE (UTE), a technique that can detect short T2* species. Experiments were performed in collagen solutions. Via a model of bi-exponential T2* with oscillation, a linear relationship (slope = 0.40 ± 0.01, R(2) = 0.99696) was determined between the UTE collagen signal fraction associated with these properties and the measured collagen concentration in solution. The UTE signal of protons in the collagen molecule was characterized as having a mean T2* of 0.75 ± 0.05 ms and a mean chemical shift of -3.56 ± 0.01 ppm relative to water at 7 T. The results indicated that collagen can be detected and quantified using UTE. A knowledge of the collagen signal properties could potentially be beneficial for the endogenous detection of myocardial fibrosis. PMID:26268158

  19. Regulation of collagen biosynthesis by ascorbic acid: a review.

    PubMed Central

    Pinnell, S. R.

    1985-01-01

    L-ascorbic acid is an essential cofactor for lysyl hydroxylase and prolyl hydroxylase, enzymes essential for collagen biosynthesis. In addition, L-ascorbic acid preferentially stimulates collagen synthesis in a manner which appears unrelated to the effect of L-ascorbic acid on hydroxylation reactions. This reaction is stereospecific and unrelated to intracellular degradation of collagen. The effect apparently occurs at a transcriptional or translational level, since L-ascorbic acid preferentially stimulates collagen-specific mRNA. In addition, it stimulates lysyl hydroxylase activity but inhibits prolyl hydroxylase activity in human skin fibroblasts in culture. PMID:3008449

  20. Thermal assembly of a biomimetic mineral/collagen composite.

    PubMed

    Pederson, Aaron W; Ruberti, Jeffrey W; Messersmith, Phillip B

    2003-11-01

    A strategy is described for exploiting temperature driven self-assembly of collagen and thermally triggered liposome mineralization to form a mineralized collagen composite from an injectable precursor fluid. Optical density and rheological experiments demonstrated the formation of a collagen gel when acid-soluble type I collagen solutions (1-7 mg/ml) were heated to 24-30 degrees C. Scanning calorimetry experiments demonstrated that mixtures of calcium- and phosphate-loaded liposomes composed of dipalmitoylphosphatidylcholine (90 mol%) and dimyristoylphosphatidylcholine (10 mol%) were stable at room temperature but formed calcium phosphate mineral when heated above 35 degrees C, a consequence of the release of entrapped salts at the lipid chain melting transition. The formation of calcium phosphate mineral induced by triggered release of calcium and phosphate was detected as an endothermic transition (deltaH=6.2+/-1.1 kcal/mol lipid) near the lipid chain melting transition (Tm=37 degrees C). Combining an acid-soluble collagen solution with calcium- and phosphate-loaded liposomes resulted in a liposome/collagen precursor fluid, which when heated from room temperature to 37 degrees C formed a mineralized collagen gel. The dynamic storage modulus of the collagen scaffold increased upon mineralization, and direct nucleation of mineral from the collagen scaffold was detected by electron microscopy. PMID:14530086

  1. Problematic game play: the diagnostic value of playing motives, passion, and playing time in men.

    PubMed

    Kneer, Julia; Rieger, Diana

    2015-01-01

    Internet gaming disorder is currently listed in the DSM-not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing. PMID:25942516

  2. Problematic Game Play: The Diagnostic Value of Playing Motives, Passion, and Playing Time in Men

    PubMed Central

    Kneer, Julia; Rieger, Diana

    2015-01-01

    Internet gaming disorder is currently listed in the DSM—not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing. PMID:25942516

  3. Play Memories and Place Identity.

    ERIC Educational Resources Information Center

    Sandberg, Anette

    2003-01-01

    This retrospective study examined play memories from childhood to adulthood of 478 university students between ages 20 and 62 as exhibited in drawings of play memories and questionnaire responses. The study focused on the role of the physical environment and place identity in play memories and individual identity development. Findings showed that…

  4. Meanings of Play among Children

    ERIC Educational Resources Information Center

    Glenn, Nicole M.; Knight, Camilla J.; Holt, Nicholas L.; Spence, John C.

    2013-01-01

    The purpose of this study was to examine meanings of play among children. Thirty-eight students aged 7-9 years from a suburban public school in Western Canada participated in focus groups. Data analysis revealed participants saw almost anything as an opportunity for play and would play almost anywhere with anyone. However, they perceived parents…

  5. Play Therapy in School Counseling

    ERIC Educational Resources Information Center

    Trice-Black, Shannon; Bailey, Carrie Lynn; Kiper Riechel, Morgan E.

    2013-01-01

    Play therapy is an empirically supported intervention used to address a number of developmental issues faced in childhood. Through the natural language of play, children and adolescents communicate feelings, thoughts, and experiences. Schools provide an ideal setting for play therapy in many ways; however, several challenges exist in implementing…

  6. Play in Evolution and Development

    ERIC Educational Resources Information Center

    Pellegrini, Anthony D.; Dupuis, Danielle; Smith, Peter K.

    2007-01-01

    In this paper we examine the role of play in human ontogeny and phylogeny, following Surplus Resource Theory. We consider how juveniles use play to sample their environment in order to develop adaptive behaviors. We speculate about how innovative behaviors developed in play in response to environmental novelty may influence subsequent evolutionary…

  7. Pretend Play and Creative Processes

    ERIC Educational Resources Information Center

    Russ, Sandra W.; Wallace, Claire E.

    2013-01-01

    The authors contend that many cognitive abilities and affective processes important in creativity also occur in pretend play and that pretend play in childhood affects the development of creativity in adulthood. They discuss a variety of theories and observations that attempt to explain the importance of pretend play to creativity. They argue that…

  8. Preschoolers' Thinking during Block Play

    ERIC Educational Resources Information Center

    Piccolo, Diana L.; Test, Joan

    2010-01-01

    Children build foundations for mathematical thinking in early play and exploration. During the preschool years, children enjoy exploring mathematical concepts--such as patterns, shape, spatial relationships, and measurement--leading them to spontaneously engage in mathematical thinking during play. Block play is one common example that engages…

  9. Tension tests on mammalian collagen fibrils.

    PubMed

    Liu, Yehe; Ballarini, Roberto; Eppell, Steven J

    2016-02-01

    A brief overview of isolated collagen fibril mechanics testing is followed by presentation of the first results testing fibrils isolated from load-bearing mammalian tendons using a microelectromechanical systems platform. The in vitro modulus (326 ± 112 MPa) and fracture stress (71 ± 23 MPa) are shown to be lower than previously measured on fibrils extracted from sea cucumber dermis and tested with the same technique. Scanning electron microscope images show the fibrils can fail with a mechanism that involves circumferential rupture, whereas the core of the fibril stays at least partially intact. PMID:26855757

  10. Elastic model for crimped collagen fibrils

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.; Doehring, Todd C.

    2005-01-01

    A physiologic constitutive expression is presented in algorithmic format for the nonlinear elastic response of wavy collagen fibrils found in soft connective tissues. The model is based on the observation that crimped fibrils in a fascicle have a three-dimensional structure at the micron scale that we approximate as a helical spring. The symmetry of this wave form allows the force/displacement relationship derived from Castigliano's theorem to be solved in closed form: all integrals become analytic. Model predictions are in good agreement with experimental observations for mitral-valve chordae tendinece.

  11. Elastic Response of Crimped Collagen Fibrils

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.; Doehring, Todd C.

    2005-01-01

    A physiologic constitutive expression is presented in algorithmic format for the elastic response of wavy collagen fibrils found in soft connective tissues. The model is based on the observation that crimped fibrils have a three-dimensional structure at the micrometer scale that we approximate as a helical spring. The symmetry of this waveform allows the force/displacement relationship derived from Castigliano's theorem to be solved in closed form. Model predictions are in good agreement with experimental observations for mitral-valve chordae tendineae

  12. Cell Alignment Driven by Mechanically Induced Collagen Fiber Alignment in Collagen/Alginate Coatings.

    PubMed

    Chaubaroux, Christophe; Perrin-Schmitt, Fabienne; Senger, Bernard; Vidal, Loïc; Voegel, Jean-Claude; Schaaf, Pierre; Haikel, Youssef; Boulmedais, Fouzia; Lavalle, Philippe; Hemmerlé, Joseph

    2015-09-01

    For many years it has been a major challenge to regenerate damaged tissues using synthetic or natural materials. To favor the healing processes after tendon, cornea, muscle, or brain injuries, aligned collagen-based architectures are of utmost interest. In this study, we define a novel aligned coating based on a collagen/alginate (COL/ALG) multilayer film. The coating exhibiting a nanofibrillar structure is cross-linked with genipin for stability in physiological conditions. By stretching COL/ALG-coated polydimethylsiloxane substrates, we developed a versatile method to align the collagen fibrils of the polymeric coating. Assays on cell morphology and alignment were performed to investigate the properties of these films. Microscopic assessments revealed that cells align with the stretched collagen fibrils of the coating. The degree of alignment is tuned by the stretching rate (i.e., the strain) of the COL/ALG-coated elastic substrate. Such coatings are of great interest for strategies that require aligned nanofibrillar biological material as a substrate for tissue engineering. PMID:25658028

  13. Defective collagen VI α6 chain expression in the skeletal muscle of patients with collagen VI-related myopathies.

    PubMed

    Tagliavini, F; Pellegrini, C; Sardone, F; Squarzoni, S; Paulsson, M; Wagener, R; Gualandi, F; Trabanelli, C; Ferlini, A; Merlini, L; Santi, S; Maraldi, N M; Faldini, C; Sabatelli, P

    2014-09-01

    Collagen VI is a non-fibrillar collagen present in the extracellular matrix (ECM) as a complex polymer; the mainly expressed form is composed of α1, α2 and α3 chains; mutations in genes encoding these chains cause myopathies known as Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM) and myosclerosis myopathy (MM). The collagen VI α6 chain is a recently identified component of the ECM of the human skeletal muscle. Here we report that the α6 chain was dramatically reduced in skeletal muscle and muscle cell cultures of genetically characterized UCMD, BM and MM patients, independently of the clinical phenotype, the gene involved and the effect of the mutation on the expression of the "classical" α1α2α3 heterotrimer. By contrast, the collagen VI α6 chain was normally expressed or increased in the muscle of patients affected by other forms of muscular dystrophy, the overexpression matching with areas of increased fibrosis. In vitro treatment with TGF-β1, a potent collagen inducer, promoted the collagen VI α6 chain deposition in the ECM of normal muscle cells, whereas, in cultures derived from collagen VI-related myopathy patients, the collagen VI α6 chain failed to develop a network outside the cells and accumulated in the endoplasmic reticulum. The defect of the α6 chain points to a contribution to the pathogenesis of collagen VI-related disorders. PMID:24907562

  14. Defective collagen VI α6 chain expression in the skeletal muscle of patients with collagen VI-related myopathies

    PubMed Central

    Tagliavini, F.; Pellegrini, C.; Sardone, F.; Squarzoni, S.; Paulsson, M.; Wagener, R.; Gualandi, F.; Trabanelli, C.; Ferlini, A.; Merlini, L.; Santi, S.; Maraldi, N.M.; Faldini, C.; Sabatelli, P.

    2014-01-01

    Collagen VI is a non-fibrillar collagen present in the extracellular matrix (ECM) as a complex polymer; the mainly expressed form is composed of α1, α2 and α3 chains; mutations in genes encoding these chains cause myopathies known as Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM) and myosclerosis myopathy (MM). The collagen VI α6 chain is a recently identified component of the ECM of the human skeletal muscle. Here we report that the α6 chain was dramatically reduced in skeletal muscle and muscle cell cultures of genetically characterized UCMD, BM and MM patients, independently of the clinical phenotype, the gene involved and the effect of the mutation on the expression of the “classical” α1α2α3 heterotrimer. By contrast, the collagen VI α6 chain was normally expressed or increased in the muscle of patients affected by other forms of muscular dystrophy, the overexpression matching with areas of increased fibrosis. In vitro treatment with TGF-β1, a potent collagen inducer, promoted the collagen VI α6 chain deposition in the ECM of normal muscle cells, whereas, in cultures derived from collagen VI-related myopathy patients, the collagen VI α6 chain failed to develop a network outside the cells and accumulated in the endoplasmic reticulum. The defect of the α6 chain points to a contribution to the pathogenesis of collagen VI-related disorders. PMID:24907562

  15. Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization

    PubMed Central

    Zhang, Zong-Kang; Li, Jie; Yan, De-Xin; Leung, Wing-Nang; Zhang, Bao-Ting

    2016-01-01

    Most acute coronary syndromes result from rupture of vulnerable atherosclerotic plaques. The collagen content of plaques may critically affect plaque stability. This study tested whether Icaritin (ICT), an intestinal metabolite of Epimedium-derived flavonoids, could alter the collagen synthesis/degradation balance in atherosclerotic lesions. Rabbits were fed with an atherogenic diet for four months. Oral administration of ICT (10 mg·kg−1·day−1) was started after two months of an atherogenic diet and lasted for two months. The collagen degradation-related parameters, including macrophages accumulation, content and activity of interstitial collagenase-1 (MMP-1), and the collagen synthesis-related parameters, including amount and distribution of smooth muscle cells (SMC) and collagen mRNA/protein levels, were evaluated in the aorta. ICT reduced plasma lipid levels, inhibited macrophage accumulation, lowered MMP-1 mRNA and protein expression, and suppressed proteolytic activity of pro-MMP-1 and MMP-1 in the aorta. ICT changed the distribution of the SMCs towards the fibrous cap of lesions without increasing the amount of SMCs. Higher collagen protein content in lesions and aorta homogenates was observed with ICT treatment compared with the atherogenic diet only, without altered collagen mRNA level. These results suggest that ICT could inhibit the collagen degradation-related factors and facilitate collagen accumulation in atherosclerotic lesions, indicating a new potential of ICT in atherosclerotic plaques. PMID:26828485

  16. Synthetic collagen heterotrimers: structural mimics of wild-type and mutant collagen type I.

    PubMed

    Gauba, Varun; Hartgerink, Jeffrey D

    2008-06-11

    Collagen type I is an AAB heterotrimer assembled from two alpha1 chains and one alpha2 chain. Missense mutations in either of these chains that substitute a glycine residue in the ubiquitous X-Y-Gly repeat with a bulky amino acid leads to osteogenesis imperfecta (OI) of varying severity. These mutations have been studied in the past using collagen-like peptide homotrimers as a model system. However, homotrimers, which by definition will contain glycine mutations in all the three chains, do not accurately mimic the mutations in their native form and result in an exaggerated effect on stability and folding. In this article, we report the design of a novel model system based upon collagen-like heterotrimers that can mimic the glycine mutations present in either the alpha1 or alpha2 chains of type I collagen. This design utilizes an electrostatic recognition motif in three chains that can force the interaction of any three peptides, including AAA (all same), AAB (two same and one different), or ABC (all different) triple helices. Therefore, the component peptides can be designed in such a way that glycine mutations are present in zero, one, two, or all three chains of the triple helix. With this design, we for the first time report collagen mutants containing one or two glycine substitutions with structures relevant to native forms of OI. Furthermore, we demonstrate the difference in thermal stability and refolding half-life times between triple helices that vary only in the frequency of glycine mutations at a particular position. PMID:18481852

  17. Epoxy Cross-Linked Collagen and Collagen-Laminin Peptide Hydrogels as Corneal Substitutes

    PubMed Central

    Koh, Li Buay; Islam, Mohammad Mirazul; Mitra, Debbie; Noel, Christopher W.; Merrett, Kimberley; Odorcic, Silvia; Fagerholm, Per; Jackson, William. Bruce; Liedberg, Bo; Phopase, Jaywant; Griffith, May

    2013-01-01

    A bi-functional epoxy-based cross-linker, 1,4-Butanediol diglycidyl ether (BDDGE), was investigated in the fabrication of collagen based corneal substitutes. Two synthetic strategies were explored in the preparation of the cross-linked collagen scaffolds. The lysine residues of Type 1 porcine collagen were directly cross-linked using l,4-Butanediol diglycidyl ether (BDDGE) under basic conditions at pH 11. Alternatively, under conventional methodology, using both BDDGE and 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) as cross-linkers, hydrogels were fabricated under acidic conditions. In this latter strategy, Cu(BF4)2·XH2O was used to catalyze the formation of secondary amine bonds. To date, we have demonstrated that both methods of chemical cross-linking improved the elasticity and tensile strength of the collagen implants. Differential scanning calorimetry and biocompatibility studies indicate comparable, and in some cases, enhanced properties compared to that of the EDC/NHS controls. In vitro studies showed that human corneal epithelial cells and neuronal progenitor cell lines proliferated on these hydrogels. In addition, improvement of cell proliferation on the surfaces of the materials was observed when neurite promoting laminin epitope, IKVAV, and adhesion peptide, YIGSR, were incorporated. However, the elasticity decreased with peptide incorporation and will require further optimization. Nevertheless, we have shown that epoxy cross-linkers should be further explored in the fabrication of collagen-based hydrogels, as alternatives to or in conjunction with carbodiimide cross-linkers. PMID:24956085

  18. Coalignment of microtubules, cytokeratin intermediate filaments, and collagen fibrils in a collagen-secreting cell system.

    PubMed

    McBeath, E; Fujiwara, K

    1989-12-01

    The distribution of microtubules and intermediate filaments in the collagen-secreting scleroblasts of the goldfish scale was investigated by immunofluorescence and electron microscopy. Many of the microtubules and cytokeratin type intermediate filaments formed bundles that were aligned with the underlying, parallel collagen fibrils. The intermediate filament bundles were evenly spaced and located adjacent to the basal plasma membrane. The microtubules, on the other hand, were located further away from the membrane, although many were found very close to the intermediate filament bundles. No detectable change was observed in scleroblast microtubules when cells on scales were treated with colchicine or cooled (greater than or equal to 0 degrees C) for up to 1 h. Cells had to be cooled overnight before the microtubules were affected. The final number and length of the microtubules in the cell depended only on the final steady-state temperature and not the temperature history of the scale cell, and steady state was reached more slowly at colder temperatures. The microtubules but not the intermediate filaments rapidly (within 5 min) and reversibly depolymerized when cells were chilled to -2 approximately -4 degrees C. When chilled cells were warmed, the microtubules polymerized back, within 15 min at room temperature, to the same pattern of parallel coalignment with the underlying collagen. They appeared to repolymerize via two different pathways: (1) a radial growth outwards from the microtubule organizing center followed by a progressive realignment with the underlying collagen and (2) a gradual and simultaneous polymerization along cold-stable, antitubulin staining fibers. These fibers were also aligned with the collagen fibrils and may be related to the aligned intermediate filaments. PMID:2483378

  19. Postnatal development of collagen structure in ovine articular cartilage

    PubMed Central

    2010-01-01

    Background Articular cartilage (AC) is the layer of tissue that covers the articulating ends of the bones in diarthrodial joints. Across species, adult AC shows an arcade-like structure with collagen predominantly perpendicular to the subchondral bone near the bone, and collagen predominantly parallel to the articular surface near the articular surface. Recent studies into collagen fibre orientation in stillborn and juvenile animals showed that this structure is absent at birth. Since the collagen structure is an important factor for AC mechanics, the absence of the adult Benninghoff structure has implications for perinatal AC mechanobiology. The current objective is to quantify the dynamics of collagen network development in a model animal from birth to maturity. We further aim to show the presence or absence of zonal differentiation at birth, and to assess differences in collagen network development between different anatomical sites of a single joint surface. We use quantitative polarised light microscopy to investigate properties of the collagen network and we use the sheep (Ovis aries) as our model animal. Results Predominant collagen orientation is parallel to the articular surface throughout the tissue depth for perinatal cartilage. This remodels to the Benninghoff structure before the sheep reach sexual maturity. Remodelling of predominant collagen orientation starts at a depth just below the future transitional zone. Tissue retardance shows a minimum near the articular surface at all ages, which indicates the presence of zonal differentiation at all ages. The absolute position of this minimum does change between birth and maturity. Between different anatomical sites, we find differences in the dynamics of collagen remodelling, but no differences in adult collagen structure. Conclusions The collagen network in articular cartilage remodels between birth and sexual maturity from a network with predominant orientation parallel to the articular surface to a

  20. Why do adult dogs 'play'?

    PubMed

    Bradshaw, John W S; Pullen, Anne J; Rooney, Nicola J

    2015-01-01

    Among the Carnivora, play behaviour is usually made up of motor patterns characteristic of predatory, agonistic and courtship behaviour. Domestic dogs are unusual in that play is routinely performed by adults, both socially, with conspecifics and with humans, and also asocially, with objects. This enhanced playfulness is commonly thought to be a side effect of paedomorphosis, the perpetuation of juvenile traits into adulthood, but here we suggest that the functions of the different types of play are sufficiently distinct that they are unlikely to have arisen through a single evolutionary mechanism. Solitary play with objects appears to be derived from predatory behaviour: preferred toys are those that can be dismembered, and a complex habituation-like feedback system inhibits play with objects that are resistant to alteration. Intraspecific social play is structurally different from interspecific play and may therefore be motivationally distinct and serve different goals; for example, dogs often compete over objects when playing with other dogs, but are usually more cooperative when the play partner is human. The majority of dogs do not seem to regard competitive games played with a human partner as "dominance" contests: rather, winning possession of objects during games appears to be simply rewarding. Play may be an important factor in sociality, since dogs are capable of extracting social information not only from games in which they participate, but also from games that they observe between third parties. We suggest that the domestic dog's characteristic playfulness in social contexts is an adaptive trait, selected during domestication to facilitate both training for specific purposes, and the formation of emotionally-based bonds between dog and owner. Play frequency and form may therefore be an indicator of the quality of dog-owner relationships. PMID:25251020

  1. Viscoelastic properties of model segments of collagen molecules.

    PubMed

    Gautieri, Alfonso; Vesentini, Simone; Redaelli, Alberto; Buehler, Markus J

    2012-03-01

    Collagen is the prime construction material in vertebrate biology, determining the mechanical behavior of connective tissues such as tendon, bone and skin. Despite extensive efforts in the investigation of the origin of collagen unique mechanical properties, a deep understanding of the relationship between molecular structure and mechanical properties remains elusive, hindered by the complex hierarchical structure of collagen-based tissues. In particular, although extensive studies of viscoelastic properties have been pursued at the macroscopic (fiber/tissue) level, fewer investigations have been performed at the smaller scales, including in particular collagen molecules and fibrils. These scales are, however, important for a complete understanding of the role of collagen as an important constituent in the extracellular matrix. Here, using an atomistic modeling approach, we perform in silico creep tests of a collagen-like peptide, monitoring the strain-time response for different values of applied external load. The results show that individual collagen molecules exhibit a nonlinear viscoelastic behavior, with a Young's modulus increasing from 6 to 16GPa (for strains up to 20%), a viscosity of 3.84.±0.38Pa·s, and a relaxation time in the range of 0.24-0.64ns. The single molecule viscosity, for the first time reported here, is several orders of magnitude lower than the viscosity found for larger-scale single collagen fibrils, suggesting that the viscous behavior of collagen fibrils and fibers involves additional mechanisms, such as molecular sliding between collagen molecules within the fibril or the effect of relaxation of larger volumes of solvent. Based on our molecular modeling results we propose a simple structural model that describes collagen tissue as a hierarchical structure, providing a bottom-up description of elastic and viscous properties form the properties of the tissue basic building blocks. PMID:22204879

  2. First stars. XIII. Two extremely metal-poor RR Lyrae stars

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Nordström, B.; Bonifacio, P.; Spite, M.; Andersen, J.; Beers, T. C.; Cayrel, R.; Spite, F.; Molaro, P.; Barbuy, B.; Depagne, E.; François, P.; Hill, V.; Plez, B.; Sivarani, T.

    2011-03-01

    Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < ~ -3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars which can be studied at high spectral resolution. Aims: We aim to determine the detailed chemical composition of the two EMP stars CS 30317-056 and CS 22881-039, originally thought to be red horizontal-branch (RHB) stars, and compare it to earlier results for EMP stars as well as to nucleosynthesis yields from various supernova (SN) models. In the analysis, we discovered that our targets are in fact the two most metal-poor RR Lyrae stars known. Methods: Our detailed abundance analysis, taking into account the variability of the stars, is based on VLT/UVES spectra (R ≃ 43 000) and 1D LTE OSMARCS model atmospheres and synthetic spectra. For comparison with SN models we also estimate NLTE corrections for a number of elements. Results: We derive LTE abundances for the 16 elements O, Na, Mg, Al, Si, S, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba, in good agreement with earlier values for EMP dwarf, giant and RHB stars. Li and C are not detected in either star. NLTE abundance corrections are newly calculated for O and Mg and taken from the literature for other elements. The resulting abundance pattern is best matched by model yields for supernova explosions with high energy and/or significant asphericity effects. Conclusions: Our results indicate that, except for Li and C, the surface composition of EMP RR Lyr stars is not significantly affected by mass loss, mixing or diffusion processes; hence, EMP RR Lyr stars should also be useful tracers of the chemical evolution of the early Galactic halo. The observed abundance ratios indicate that these stars were born from an ISM polluted by energetic, massive (25-40 M⊙) and /or aspherical supernovae, but the NLTE corrections for Sc and certain other elements do play a role in the choice of model. Based on

  3. Thinking about Children's Play: Play Is Not Work, Nor Is Work Play.

    ERIC Educational Resources Information Center

    Elkind, David

    2001-01-01

    Addresses the concept of "play as a child's work," from the viewpoints of Montessori, Freud, and Piaget. Contends that children's play: (1) like adult play, may be individual or social; (2) has immediate value for the child as a way of expressing feelings; and (3) is a healthy counterpoise to work. (SD)

  4. Effect of Factor XIII-A G185T Polymorphism on Visual Prognosis after Photodynamic Therapy for Neovascular Macular Degeneration

    PubMed Central

    Parmeggiani, Francesco; Costagliola, Ciro; Semeraro, Francesco; Romano, Mario R; Rinaldi, Michele; Gallenga, Carla Enrica; Serino, Maria Luisa; Incorvaia, Carlo; D’Angelo, Sergio; De Nadai, Katia; Dell’Omo, Roberto; Russo, Andrea; Gemmati, Donato; Perri, Paolo

    2015-01-01

    Macular degenerations represent leading causes of central blindness or low vision in developed countries. Most of these severe visual disabilities are due to age-related macular degeneration (AMD) and pathologic myopia (PM), both of which are frequently complicated by subfoveal choroidal neovascularization (CNV). Photodynamic therapy with verteporfin (PDT-V) is still employed for CNV treatment in selected cases or in combined regimen. In Caucasian patients, the common polymorphism G185T of factor XIII-A gene (FXIII-A-G185T; rs5985) has been described as predictor of poor angiographic CNV responsiveness to PDT-V. Nevertheless, the prognostic implications of this pharmacogenetic determinant on long-term visual outcome after a PDT-V regimen have not been evaluated. We retrospectively selected Caucasian patients presenting with treatment-naive CNV and receiving standardized PDT-V protocol for two years. The study population included patients affected by subfoveal CNV secondary to AMD or PM. We assessed the correlations between the polymorphic allele T of FXIII-A-G185T and: (1) total number of photodynamic treatments; and (2) change in visual acuity from baseline to the end of the follow-up period. Considering a total study population of 412 patients with neovascular AMD or PM, the carriers of 185 T-allele of FXIII-A (GT or TT genotype) received a higher number of photodynamic treatments than patients without it (GG wild-type genotype) (p < 0.01; mean number of PDT-V: 5.51 vs. 3.76, respectively). Moreover, patients with 185 T-allele of FXIII-A had a more marked worsening of visual acuity at 24 months than those with the GG-185 wild genotype (p < 0.01; mean difference in logMAR visual acuity: 0.22 vs. 0.08, respectively). The present findings show that the G185T polymorphism of the FXIII-A gene is associated with significant differences in the long-term therapeutic outcomes of patients treated with standardized PDT-V protocol. The comprehensive appraisal of both anti

  5. First cases of severe congenital factor XIII deficiency in Southwestern Afghanistan in the vicinity of southeast of Iran.

    PubMed

    Hosseini, Soudabeh; Dorgalaleh, Akbar; Bamedi, Taregh; Tavakol, Khanagha; Tabibian, Shadi; Naderi, Majid; Alizadeh, Shaban; Varmaghani, Bijan; Shamsizadeh, Morteza; Rahimizadeh, Aziz; Ebrahimi, Sharif

    2015-12-01

    Factor XIII deficiency (FXIIID) is an extremely rare bleeding disorder with the highest global incidence in southeast of Iran. Southwestern Afghanistan (Nimruz Province) is located near the border with Iran in the vicinity of Sistan and Baluchestan Province in southeast Iran, and there seems to be a high prevalence of FXIIID in Nimruz. Thus, this cross-sectional study was designed to assess the prevalence of FXIIID, molecular basis as well as clinical manifestations of FXIIID in Southwestern Afghanistan. During the course of the study, all patients suspected of FXIIID were clinically examined and assessed by routine coagulation tests, including bleeding time, activated partial thromboplastin time, prothrombin time, as well as platelet count and clot solubility test. Patients with normal routine coagulation tests, but abnormal clot solubility test, underwent further investigations by FXIII activity, as well as molecular analysis for FXIII-A gene mutation (Trp187Arg) by PCR-restriction fragment length polymorphism that confirmed by sequencing. Patients with confirmed FXIIID deficiency were registered to receive prophylaxis treatment. All data including demographic information, clinical manifestations, as well as therapeutic response and type and duration of treatment, were recorded, and the data were analyzed by SPSS software. In this cross-sectional study, we found five patients with abnormal clot solubility test, among whom two patients abandoned the study, whereas three patients remained for a more precise study. All the patients were residents of Zaranj city, the capital of Nimruz Province. All these patients had undetectable activity of FXIII, which indicates a severe deficiency. Molecular analysis of patients showed mutation of Trp187Arg in all of them. Hematoma was the most common clinical presentation leading to diagnosis of FXIIID in these patients (100%). Epistaxis (67%), gum bleeding (33%), and hematuria (33%) were other recurrent clinical presentations of

  6. Acquired Factor XIII Inhibitor in Hospitalized and Perioperative Patients: A Systematic Review of Case Reports and Case Series.

    PubMed

    Tone, Kira J; James, Tyler E; Fergusson, Dean A; Tinmouth, Alan; Tay, Jason; Avey, Marc T; Kilty, Shaun; Lalu, Manoj M

    2016-07-01

    Factor XIII (FXIII) cross-links fibrin monomers to support clot stabilization and wound healing. Acquired FXIII deficiency is caused by autoantibodies that inhibit FXIII and can result in bleeding despite normal routine coagulation test results. Given the rarity of this disease, large clinical studies are not feasible. We therefore conducted a systematic review of case reports and case series of acquired FXIII inhibitor to evaluate potential management and treatment strategies for acquired FXIII inhibitor in hospitalized and/or perioperative patients. A systematic search of MEDLINE, Embase, and Web of Science identified reports of hospitalized and perioperative patients with acquired FXIII deficiency. No restrictions were placed on language or publication type. Article screening and data extraction were performed independently by 2 abstractors. Completeness of reporting was evaluated according to modified elements from the CAse REport (CARE) guidelines. A total of 1028 citations were reviewed, with 36 case reports and 3 case series meeting eligibility criteria (63 patients total). The mean age was 60 (range, 9-87) years with balanced sex representation. At presentation, 48 patients (76%) had intramuscular or subcutaneous bleeding, and 34 patients (54%) had external or surgical bleeding. All cases were diagnosed by initially detecting a FXIII deficiency and then identifying the inhibitor. Clinical improvement in bleeding was seen in patients receiving FXIII concentrate (13/17 patients), cryoprecipitate (5/8), and plasma (10/18). Inhibitor reduction was seen in patients who received rituximab (6/6 patients), plasma exchange (2/2), intravenous immunoglobulin (4/5), steroid (15/20), and cyclophosphamide (10/15). Concurrent initiation of multiple therapies and obvious lack of control comparisons made direct association to outcomes difficult to establish. Outcomes were reported for 55 patients, with 25 patients (45%) having complete inhibitor eradication and 15 patients

  7. Effect of Factor XIII-A G185T Polymorphism on Visual Prognosis after Photodynamic Therapy for Neovascular Macular Degeneration.

    PubMed

    Parmeggiani, Francesco; Costagliola, Ciro; Semeraro, Francesco; Romano, Mario R; Rinaldi, Michele; Gallenga, Carla Enrica; Serino, Maria Luisa; Incorvaia, Carlo; D'Angelo, Sergio; De Nadai, Katia; Dell'Omo, Roberto; Russo, Andrea; Gemmati, Donato; Perri, Paolo

    2015-01-01

    Macular degenerations represent leading causes of central blindness or low vision in developed countries. Most of these severe visual disabilities are due to age-related macular degeneration (AMD) and pathologic myopia (PM), both of which are frequently complicated by subfoveal choroidal neovascularization (CNV). Photodynamic therapy with verteporfin (PDT-V) is still employed for CNV treatment in selected cases or in combined regimen. In Caucasian patients, the common polymorphism G185T of factor XIII-A gene (FXIII-A-G185T; rs5985) has been described as predictor of poor angiographic CNV responsiveness to PDT-V. Nevertheless, the prognostic implications of this pharmacogenetic determinant on long-term visual outcome after a PDT-V regimen have not been evaluated. We retrospectively selected Caucasian patients presenting with treatment-naive CNV and receiving standardized PDT-V protocol for two years. The study population included patients affected by subfoveal CNV secondary to AMD or PM. We assessed the correlations between the polymorphic allele T of FXIII-A-G185T and: (1) total number of photodynamic treatments; and (2) change in visual acuity from baseline to the end of the follow-up period. Considering a total study population of 412 patients with neovascular AMD or PM, the carriers of 185 T-allele of FXIII-A (GT or TT genotype) received a higher number of photodynamic treatments than patients without it (GG wild-type genotype) (p < 0.01; mean number of PDT-V: 5.51 vs. 3.76, respectively). Moreover, patients with 185 T-allele of FXIII-A had a more marked worsening of visual acuity at 24 months than those with the GG-185 wild genotype (p < 0.01; mean difference in logMAR visual acuity: 0.22 vs. 0.08, respectively). The present findings show that the G185T polymorphism of the FXIII-A gene is associated with significant differences in the long-term therapeutic outcomes of patients treated with standardized PDT-V protocol. The comprehensive appraisal of both anti

  8. Corneal collagen cross-linking: a review.

    PubMed

    O'Brart, David P S

    2014-01-01

    The aim was to review the published literature on corneal collagen cross-linking. The emphasis was on the seminal publications, systemic reviews, meta-analyses and randomized controlled trials. Where such an evidence did not exist, selective large series cohort studies, case controlled studies and case series with follow-up preferably greater than 12 months were included. Riboflavin/Ultraviolet A (UVA) corneal collagen cross-linking appears to be the first treatment modality to halt the progression of keratoconus and other corneal ectatic disorders with improvement in visual, keratometric and topographic parameters documented by most investigators. Its precise mechanism of action at a molecular level is as yet not fully determined. Follow-up is limited to 4-6 years at present but suggests continued stability and improvement in corneal shape with time. Most published data are with epithelium-off techniques. Epithelium-on studies suggest some efficacy but less than with the epithelium-off procedures and long-term data are not currently available. The use of Riboflavin/UVA CXL for the management of infectious and non-infectious keratitis appears very promising. Its use in the management of bullous keratopathy is equivocal. Investigation of other methodologies for CXL are under investigation. PMID:25000866

  9. Corneal collagen cross-linking: A review

    PubMed Central

    O’Brart, David P.S.

    2014-01-01

    The aim was to review the published literature on corneal collagen cross-linking. The emphasis was on the seminal publications, systemic reviews, meta-analyses and randomized controlled trials. Where such an evidence did not exist, selective large series cohort studies, case controlled studies and case series with follow-up preferably greater than 12 months were included. Riboflavin/Ultraviolet A (UVA) corneal collagen cross-linking appears to be the first treatment modality to halt the progression of keratoconus and other corneal ectatic disorders with improvement in visual, keratometric and topographic parameters documented by most investigators. Its precise mechanism of action at a molecular level is as yet not fully determined. Follow-up is limited to 4–6 years at present but suggests continued stability and improvement in corneal shape with time. Most published data are with epithelium-off techniques. Epithelium-on studies suggest some efficacy but less than with the epithelium-off procedures and long-term data are not currently available. The use of Riboflavin/UVA CXL for the management of infectious and non-infectious keratitis appears very promising. Its use in the management of bullous keratopathy is equivocal. Investigation of other methodologies for CXL are under investigation. PMID:25000866

  10. Ameloblasts express type I collagen during amelogenesis.

    PubMed

    Assaraf-Weill, N; Gasse, B; Silvent, J; Bardet, C; Sire, J Y; Davit-Béal, T

    2014-05-01

    Enamel and enameloid, the highly mineralized tooth-covering tissues in living vertebrates, are different in their matrix composition. Enamel, a unique product of ameloblasts, principally contains enamel matrix proteins (EMPs), while enameloid possesses collagen fibrils and probably receives contributions from both odontoblasts and ameloblasts. Here we focused on type I collagen (COL1A1) and amelogenin (AMEL) gene expression during enameloid and enamel formation throughout ontogeny in the caudate amphibian, Pleurodeles waltl. In this model, pre-metamorphic teeth possess enameloid and enamel, while post-metamorphic teeth possess enamel only. In first-generation teeth, qPCR and in situ hybridization (ISH) on sections revealed that ameloblasts weakly expressed AMEL during late-stage enameloid formation, while expression strongly increased during enamel deposition. Using ISH, we identified COL1A1 transcripts in ameloblasts and odontoblasts during enameloid formation. COL1A1 expression in ameloblasts gradually decreased and was no longer detected after metamorphosis. The transition from enameloid-rich to enamel-rich teeth could be related to a switch in ameloblast activity from COL1A1 to AMEL synthesis. P. waltl therefore appears to be an appropriate animal model for the study of the processes involved during enameloid-to-enamel transition, especially because similar events probably occurred in various lineages during vertebrate evolution. PMID:24570147

  11. Diaphragmatic dysfunction in Collagen VI myopathies.

    PubMed

    Quijano-Roy, S; Khirani, S; Colella, M; Ramirez, A; Aloui, S; Wehbi, S; de Becdelievre, A; Carlier, R Y; Allamand, V; Richard, P; Azzi, V; Estournet, B; Fauroux, B

    2014-02-01

    Collagen VI-related myopathies are hereditary disorders causing progressive restrictive respiratory insufficiency. Specific diaphragm involvement has been suggested by a drop in supine volumes. This pilot study aimed at characterizing the respiratory muscle phenotype in patients with COL6A1-3 genes mutations. Lung function, blood gases, muscle strength and respiratory mechanics were measured in 7 patients between 2002 and 2012. Patients were classified as Early-Severe (n = 3), Moderate-Progressive (n = 2) and Mild (n = 2) according to clinical disease presentation. Seven patients (aged 6-28) were evaluated. Forced vital capacity distinguished the Mild group (>60% predicted) from the two other groups (<50% predicted). This distinction was also possible using the motor function measure scale. Diaphragmatic dysfunction at rest was observed in all the Early-Severe and Moderate-Progressive patients. During a voluntary sniff maneuver diaphragmatic dysfunction was observed in all patients, as assessed by a negative gastric pressure. All patients had diaphragmatic fatigue assessed by a tension-time index over the threshold of 0.15. Diaphragmatic dysfunction during a maximal voluntary maneuver and diaphragmatic fatigue are constant features in Collagen VI myopathies. These observations can assist the diagnosis and should be taken in account for the clinical management, with the early detection of sleep-disordered breathing. PMID:24314752

  12. Stress relaxation of swine growth plate in semi-confined compression: depth dependent tissue deformational behavior versus extracellular matrix composition and collagen fiber organization.

    PubMed

    Amini, Samira; Mortazavi, Farhad; Sun, Jun; Levesque, Martin; Hoemann, Caroline D; Villemure, Isabelle

    2013-01-01

    growth direction in the proliferative and hypertrophic zones. Higher strains were developed in growth plate areas (proliferative and hypertrophic) composed of lower collagen content and of vertical collagen fiber organization. The stiffer reserve zone, with its higher collagen content and collagen fibers oriented to restrain lateral expansion under compression, could play a greater role of mechanical support compared to the proliferative and hypertrophic zones, which could be more susceptible to be involved in an abnormal growth process. PMID:22446833

  13. Collagen-hyaluronic acid scaffolds for adipose tissue engineering.

    PubMed

    Davidenko, N; Campbell, J J; Thian, E S; Watson, C J; Cameron, R E

    2010-10-01

    Three-dimensional (3-D) in vitro models of the mammary gland require a scaffold matrix that supports the development of adipose stroma within a robust freely permeable matrix. 3-D porous collagen-hyaluronic acid (HA: 7.5% and 15%) scaffolds were produced by controlled freeze-drying technique and crosslinking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. All scaffolds displayed uniform, interconnected pore structure (total porosity approximately 85%). Physical and chemical analysis showed no signs of collagen denaturation during the formation process. The values of thermal characteristics indicated that crosslinking occurred and that its efficiency was enhanced by the presence of HA. Although the crosslinking reduced the swelling of the strut material in water, the collagen-HA matrix as a whole tended to swell more and show higher dissolution resistance than pure collagen samples. The compressive modulus and elastic collapse stress were higher for collagen-HA composites. All the scaffolds were shown to support the proliferation and differentiation 3T3-L1 preadipocytes while collagen-HA samples maintained a significantly increased proportion of cycling cells (Ki-67+). Furthermore, collagen-HA composites displayed significantly raised Adipsin gene expression with adipogenic culture supplementation for 8 days vs. control conditions. These results indicate that collagen-HA scaffolds may offer robust, freely permeable 3-D matrices that enhance mammary stromal tissue development in vitro. PMID:20466086

  14. The collagen microfibril model, a tool for biomaterials scientists

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal hides, a major byproduct of the meat industry, are a rich source of collagen, a structural protein of the extracellular matrix that gives strength and form to the skin, tendons and bones of mammals. The structure of fibrous collagen, a long triple helix that self-associates in a staggered arr...

  15. Structural investigations on native collagen type I fibrils using AFM

    SciTech Connect

    Strasser, Stefan; Zink, Albert; Janko, Marek; Heckl, Wolfgang M.; Thalhammer, Stefan . E-mail: stefan.thalhammer@gsf.de

    2007-03-02

    This study was carried out to determine the elastic properties of single collagen type I fibrils with the use of atomic force microscopy (AFM). Native collagen fibrils were formed by self-assembly in vitro characterized with the AFM. To confirm the inner assembly of the collagen fibrils, the AFM was used as a microdissection tool. Native collagen type I fibrils were dissected and the inner core uncovered. To determine the elastic properties of collagen fibrils the tip of the AFM was used as a nanoindentor by recording force-displacement curves. Measurements were done on the outer shell and in the core of the fibril. The structural investigations revealed the banding of the shell also in the core of native collagen fibrils. Nanoindentation experiments showed the same Young's modulus on the shell as well as in the core of the investigated native collagen fibrils. In addition, the measurements indicate a higher adhesion in the core of the collagen fibrils compared to the shell.

  16. A rare cause of protein losing enteropathy: collagenous sprue.

    PubMed

    Karakuş, Esra; Ekinci, Özgür; Kırsaçlıoğlu, Ceyda Tuna; Özaydın, Eda; Atakan, Canan; Dursun, Ayşe

    2015-04-01

    Collagenous sprue is a clinicopathological entity with an unknown etiology. Its clinical features include progressive malabsorption, diarrhea, weight loss, unresponsiveness to treatment, and high mortality rates. The age interval of collagenous sprue is quite broad and ranges between 2 and 85 years. As far as to our knowledge, the presented case is the first reported case in infancy. PMID:25514205

  17. Electrophoretic mobility patterns of collagen following laser welding

    NASA Astrophysics Data System (ADS)

    Bass, Lawrence S.; Moazami, Nader; Pocsidio, Joanne O.; Oz, Mehmet C.; LoGerfo, Paul; Treat, Michael R.

    1991-06-01

    Clinical application of laser vascular anastomosis in inhibited by a lack of understanding of its mechanism. Whether tissue fusion results from covalent or non-covalent bonding of collagen and other structural proteins is unknown. We compared electrophoretic mobility of collagen in laser treated and untreated specimens of rat tail tendon (>90% type I collagen) and rabbit aorta. Welding was performed, using tissue shrinkage as the clinical endpoint, using the 808 nm diode laser (power density 14 watts/cm2) and topical indocyanine green dye (max absorption 805 nm). Collagen was extracted with 8 M urea (denaturing), 0.5 M acetic acid (non-denaturing) and acetic acid/pepsin (cleaves non- helical protein). Mobility patterns on gel electrophoresis (SDS-PAGE) after urea or acetic acid extraction were identical in the lasered and control tendon and vessel (confirmed by optical densitometry), revealing no evidence of formation of novel covalent bonds. Alpha and beta band intensity was diminished in pepsin incubated lasered specimens compared with controls (optical density ratio 0.00 +/- 9 tendon, 0.65 +/- 0.12 aorta), indicating the presence of denatured collagen. With the laser parameters used, collagen is denatured without formation of covalent bonds, suggesting that non-covalent interaction between denatured collagen molecules may be responsible for the weld. Based on this mechanism, welding parameters can be chosen which produce collagen denaturation without cell death.

  18. Cellular Origins of Type IV Collagen Networks in Developing Glomeruli

    PubMed Central

    Abrahamson, Dale R.; Hudson, Billy G.; Stroganova, Larysa; Borza, Dorin-Bogdan; St. John, Patricia L.

    2009-01-01

    Laminin and type IV collagen composition of the glomerular basement membrane changes during glomerular development and maturation. Although it is known that both glomerular endothelial cells and podocytes produce different laminin isoforms at the appropriate stages of development, the cellular origins for the different type IV collagen heterotrimers that appear during development are unknown. Here, immunoelectron microscopy demonstrated that endothelial cells, mesangial cells, and podocytes of immature glomeruli synthesize collagen α1α2α1(IV). However, intracellular labeling revealed that podocytes, but not endothelial or mesangial cells, contain collagen α3α4α5(IV). To evaluate the origins of collagen IV further, we transplanted embryonic kidneys from Col4a3-null mutants (Alport mice) into kidneys of newborn, wildtype mice. Hybrid glomeruli within grafts containing numerous host-derived, wildtype endothelial cells never expressed collagen α3α4α5(IV). Finally, confocal microscopy of glomeruli from infant Alport mice that had been dually labeled with anti-collagen α5(IV) and the podocyte marker anti-GLEPP1 showed immunolabeling exclusively within podocytes. Together, these results indicate that collagen α3α4α5(IV) originates solely from podocytes; therefore, glomerular Alport disease is a genetic defect that manifests specifically within this cell type. PMID:19423686

  19. Cellular origins of type IV collagen networks in developing glomeruli.

    PubMed

    Abrahamson, Dale R; Hudson, Billy G; Stroganova, Larysa; Borza, Dorin-Bogdan; St John, Patricia L

    2009-07-01

    Laminin and type IV collagen composition of the glomerular basement membrane changes during glomerular development and maturation. Although it is known that both glomerular endothelial cells and podocytes produce different laminin isoforms at the appropriate stages of development, the cellular origins for the different type IV collagen heterotrimers that appear during development are unknown. Here, immunoelectron microscopy demonstrated that endothelial cells, mesangial cells, and podocytes of immature glomeruli synthesize collagen alpha 1 alpha 2 alpha1(IV). However, intracellular labeling revealed that podocytes, but not endothelial or mesangial cells, contain collagen alpha 3 alpha 4 alpha 5(IV). To evaluate the origins of collagen IV further, we transplanted embryonic kidneys from Col4a3-null mutants (Alport mice) into kidneys of newborn, wildtype mice. Hybrid glomeruli within grafts containing numerous host-derived, wildtype endothelial cells never expressed collagen alpha 3 alpha 4 alpha 5(IV). Finally, confocal microscopy of glomeruli from infant Alport mice that had been dually labeled with anti-collagen alpha 5(IV) and the podocyte marker anti-GLEPP1 showed immunolabeling exclusively within podocytes. Together, these results indicate that collagen alpha 3 alpha 4 alpha 5(IV) originates solely from podocytes; therefore, glomerular Alport disease is a genetic defect that manifests specifically within this cell type. PMID:19423686

  20. Vascular tube formation on matrix metalloproteinase-1-damaged collagen

    PubMed Central

    Varani, J; Perone, P; Warner, R L; Dame, M K; Kang, S; Fisher, G J; Voorhees, J J

    2008-01-01

    Connective tissue damage and angiogenesis are both important features of tumour growth and invasion. Here, we show that endothelial cells maintained on a three-dimensional lattice of intact polymerised collagen formed a monolayer of cells with a cobblestone morphology. When the collagen was exposed to organ culture fluid from human basal cell tumours of the skin (containing a high level of active matrix metalloproteinase-1 (MMP-1)), degradation of the collagen matrix occurred. The major degradation products were the $3over 4$- and $1over 4$-sized fragments known to result from the action of MMP-1 on type I collagen. When endothelial cells were maintained on the partially degraded collagen, the cells organised into a network of vascular tubes. Pretreatment of the organ culture fluid with either tissue inhibitor of metalloproteinase-1 (TIMP-1) or neutralising antibody to MMP-1 prevented degradation of the collagen lattice and concomitantly inhibited endothelial cell organisation into the vascular network. Purified (activated) MMP-1 duplicated the effects of skin organ culture fluid, but other enzymes including MMP-9 (gelatinase B), elastase or trypsin failed to produce measurable fragments from intact collagen and also failed to promote vascular tube formation. Together, these studies suggest that damage to the collagenous matrix is itself an important inducer of new vessel formation. PMID:18443597