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Sample records for collagen xiii play

  1. Collagen XIII secures pre- and postsynaptic integrity of the neuromuscular synapse.

    PubMed

    Härönen, Heli; Zainul, Zarin; Tu, Hongmin; Naumenko, Nikolay; Sormunen, Raija; Miinalainen, Ilkka; Shakirzyanova, Anastasia; Oikarainen, Tuomo; Abdullin, Azat; Martin, Paula; Santoleri, Sabrina; Koistinaho, Jari; Silmanl, Israel; Giniatullin, Rashid; Fox, Michael A; Heikkinen, Anne; Pihlajaniemi, Taina

    2017-03-24

    Both transmembrane and extracellular cues, one of which is collagen XIII, regulate formation and function of the neuromuscular synapse, and their absence results in myasthenia. We show that the phenotypical changes in collagen XIII knock-out mice are milder than symptoms in human patients, but the Col13a1-/- mice recapitulate major muscle findings of congenital myasthenic syndrome type 19 and serve as a disease model. In the lack of collagen XIII neuromuscular synapses do not reach full size, alignment, complexity and function resulting in reduced muscle strength. Collagen XIII is particularly important for the preterminal integrity, and when absent, destabilization of the motor nerves results in muscle regeneration and in atrophy especially in the case of slow muscle fibers. Collagen XIII was found to affect synaptic integrity through binding the ColQ tail of acetylcholine esterase. Although collagen XIII is a muscle-bound transmembrane molecule it also undergoes ectodomain shedding to become, a synaptic basal lamina component. We investigated the two forms' roles by novel Col13a1tm/tm mice in which ectodomain shedding is impaired. While postsynaptic maturation, terminal branching and neurotransmission was exaggerated in the Col13a1tm/tm mice, the transmembrane form's presence sufficed to prevent defects in transsynaptic adhesion, Schwann cell invagination/retraction, vesicle accumulation and acetylcholine receptor clustering and acetylcholinesterase dispersion seen in the Col13a1-/- mice, pointing to the transmembrane form as the major conductor of collagen XIII effects. Altogether, collagen XIII secures postsynaptic, synaptic and presynaptic integrity, and it is required for gaining and maintaining normal size, complexity and functional capacity of the neuromuscular synapse.

  2. Expression of mRNAs coding for the alpha 1 chain of type XIII collagen in human fetal tissues: comparison with expression of mRNAs for collagen types I, II, and III

    PubMed Central

    1989-01-01

    This paper describes the topographic distribution of the multiple mRNAs coding for a novel human short-chain collagen, the alpha 1 chain of type XIII collagen. To identify the tissues and cells expressing these mRNAs, human fetal tissues of 15-19 gestational wk were studied by Northern and in situ hybridizations. The distribution pattern of the type XIII collagen mRNAs was compared with that of fibrillar collagen types I, II, and III using specific human cDNA probes for each collagen type. Northern hybridization showed the bone, cartilage, intestine, skin, and striated muscle to contain mRNAs for type XIII collagen. An intense in situ hybridization signal was obtained with the type XIII collagen cDNAs in the epidermis, hair follicles, and nail root cells of the skin, whereas the fibrillar collagen mRNAs were detected in the dermis. Cells in the intestinal mucosal layer also appeared to contain high levels of alpha 1(XIII) collagen mRNAs, but contained none of the fibrillar collagen mRNAs. In the bone and striated muscle, alpha 1(XIII) collagen mRNAs were detected in the mesenchymal cells forming the reticulin fibers of the bone marrow and endomycium. The hybridization signal obtained with the alpha 1(XIII) collagen cDNA probe in cartilaginous areas of the growth plates was similar, but less intense, to that obtained with the type II collagen probe. A clear hybridization signal was also detected at the (pre)articular surfaces and at the margins of the epiphyses, whereas it was weaker in the resting chondrocytes in the middle of the epiphyses. The brain, heart, kidney, liver, lung, placenta, spleen, testis, tendon, and thymus did not appear to contain alpha 1(XIII) collagen mRNAs. PMID:2768343

  3. 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.

  4. Advances of Coagulation Factor XIII

    PubMed Central

    Shi, Da-Yu; Wang, Shu-Jie

    2017-01-01

    Objective: To provide a comprehensive literature review on roles of coagulation factor XIII (FXIII) in coagulation, wound healing, neoplasm, bone metabolism, and pregnancy. Data Sources: All articles in PubMed with key words Coagulation factor XIII, wound, leukemia, tumor, bone, and pregnancy with published date from 2001 to 2016 were included in the study. Frequently cited publications before 2000 were also included. Study Selection: We reviewed the role of FXIII in biologic processes as documented in clinical, animal, and in vitro studies. Results: FXIII, a member of the transglutaminase (TG) family, plays key roles in various biological processes. Besides its well-known function in coagulation, the cross-linking of small molecules catalyzed by FXIII has been found in studies to help promote wound healing, improve bone metabolism, and prevent miscarriages. The study has also shown that FXIII concentration level differs in the blood of patients with leukemia and solid tumors and offers promises as a diagnostic indicator. Conclusions: FXIII has many more biologic functions besides being known as coagulation factor. The TG activity of FXIII contributes to several processes, including wound healing, bone extracellular matrix stabilization, and the interaction between embryo and decidua of uterus. Further research is needed to elucidate the link between FXIII and leukemia and solid tumors. PMID:28091415

  5. OSCAR-collagen signaling in monocytes plays a proinflammatory role and may contribute to the pathogenesis of rheumatoid arthritis.

    PubMed

    Schultz, Heidi S; Guo, Li; Keller, Pernille; Fleetwood, Andrew J; Sun, Mingyi; Guo, Wei; Ma, Chunyan; Hamilton, John A; Bjørkdahl, Olle; Berchtold, Martin W; Panina, Svetlana

    2016-04-01

    Osteoclast-associated receptor (OSCAR) is an activating receptor expressed by human myeloid cells. Collagen type I (ColI) and collagen type II (ColII) serve as ligands for OSCAR. OSCAR-collagen interaction stimulates RANK-dependent osteoclastogenesis. We have recently reported that OSCAR promotes functional maturation of monocyte-derived dendritic cells. OSCAR is upregulated on monocytes from rheumatoid arthritis (RA) patients with active disease, and these monocytes show an increased proosteoclastogenic potential. In the current study, we have addressed a functional role for an OSCAR-collagen interaction on monocytes. We show that OSCAR-ColII signaling promoted the survival of monocytes. Moreover, ColII stimulated the release of proinflammatory cytokines by monocytes from healthy donors, which could be completely blocked by an anti-OSCAR monoclonal antibody. Mononuclear cells from the synovial fluid of RA patients plated on ColII secreted TNF-α and IL-8 in an OSCAR-dependent manner. Global RNA profiling showed that components of multiple signaling pathways relevant to RA pathogenesis are regulated at the transcriptional level by OSCAR in monocytes. Thus, OSCAR can play a proinflammatory role in monocyte-derived cells and may contribute crucially on multiple levels to RA pathogenesis.

  6. 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…

  7. The NC16A domain of collagen XVII plays a role in triple helix assembly and stability.

    PubMed

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

    2006-12-01

    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 GPP(10) 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.

  8. DDR2 plays a role in fibroblast migration independent of adhesion ligand and collagen activated DDR2 tyrosine kinase.

    PubMed

    Herrera-Herrera, Mireya Liliana; Quezada-Calvillo, Roberto

    2012-12-07

    Discoidin domain receptor-2 (DDR2) is a cell surface tyrosine kinase receptor that can be activated by soluble collagen and has been implicated in diverse physiological functions including organism growth and wound repair. In the current studies, we used fibronectin and collagen-coated 2D surfaces and collagen matrices in combination with siRNA technology to investigate the role of DDR2 in a range of fibroblast motile activities. Silencing DDR2 with siRNA inhibited cell spreading and migration, and similar inhibition occurred regardless whether cells were interacting with fibronectin or collagen surfaces. Under the assay conditions used, DDR2 tyrosine kinase activation was not observed unless soluble collagen was added to the incubation medium. Finally silencing DDR2 also inhibited human fibroblast migration in 3D collagen matrices but had no effect on 3D collagen matrix remodeling and contraction. Taken together, our findings suggest that DDR2 is required for normal fibroblast spreading and migration independent of adhesion ligand and collagen activation of DDR2 tyrosine kinase.

  9. 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.

  10. [Coagulation factor XIII – Pathophysiology, clinic and therapy of factor XIII deficiency].

    PubMed

    Weber, Christian Friedrich; Adam, Elisabeth Hannah; Pape, Andreas; Jöst, Marina; Meybohm, Patrick; Schmitz, Katja; Zacharowski, Kai; Hermann, Martin; Fries, Dietmar

    2015-11-01

    The complex activity of the transglutaminase factor XIII (FXIII) comprises central functions in secondary hemostasis. Congenital or acquired FXIII deficiencies may be associated with habitual abortions, impaired wound healing, coagulopathy and fatal hemorrhage. The present review describes physiological functions of FXIII, as well as pathophysiology, diagnostic and therapeutic options of FXIII deficiencies.

  11. [Factor XIII : Pharmacodynamic and pharmacokinetic characteristics].

    PubMed

    Adam, E H; Kreuer, S; Zacharowski, K; Weber, C F; Wildenauer, R

    2017-01-01

    Factor XIII (FXIII) plays an important role in the field of blood coagulation. In the last decade, both congenital and acquired deficiencies have been investigated in clinical studies. FXIII is a versatile enzyme that leads to a covalent cross-linking of fibrin fibrils at the end of the clotting cascade and supports platelet adhesion to the damaged sub-endothelium with the result of a mechanically stable clot.Symptoms of FXIII deficiencies vary within a broad spectrum from superficial skin bleeding episodes to severe, sometimes life threatening hemorrhage, requiring prophylactic or therapeutic replacement therapy.Since 1993 purified plasma-derived FXIII concentrate has been available in Germany, large parts of Europe and in the USA and Canada. The administration is conducted intravenously, and FXIII is immediately available in the plasma. The dosage should be determined by measuring actual plasma FXIII-activity. Repetitive application is possible, especially with regard to the mean half-time of 7.9 days.Administration is considered to be safe and effective, but there are some case reports, as with other coagulation factors, describing the appearance of inhibitory antibodies.This summary seeks to provide an insight into the principle pharmacokinetic and pharmacodynamic characteristics of plasma-derived FXIII concentrate, reviewing the current literature. For detailed use in clinical settings, the application of FXIII concentrate or substitution therapy with fresh frozen plasma, we therefore refer to current guidelines and significant studies that have been recently published.

  12. Platelets activated by collagen through the immunoreceptor tyrosine-based activation motif in the Fc receptor gamma-chain play a pivotal role in the development of myocardial ischemia-reperfusion injury.

    PubMed

    Takaya, Norihide; Katoh, Youichi; Iwabuchi, Kazuhisa; Hayashi, Ichiro; Konishi, Hakuoh; Itoh, Seigo; Okumura, Ko; Ra, Chisei; Nagaoka, Isao; Daida, Hiroyuki

    2005-12-01

    Platelet activation and the formation of platelet microaggregates in coronary vessels play pivotal roles in myocardial ischemia and reperfusion injury. The Fc receptor gamma-chain (FcR gamma) is coexpressed with glycoprotein (GP) VI, forming a platelet collagen receptor, and the activation of platelets by collagen is closely coupled with tyrosine phosphorylation of the FcRgamma. To examine the functional significance of platelet FcR gamma/GPVI complex in the early phase of myocardial ischemia and reperfusion injury in mice, we performed coronary occlusion and reperfusion experiments using wild type mice and FcRgamma-deficient (FcRgamma(-/-)) mice that lack GPVI. The infarct size was significantly smaller in FcRgamma(-/-) mice subjected to occlusion and reperfusion of the coronary artery than in control FcR gamma(+/+) mice. Twenty-four hours after the reperfusion, electron microscopy of the injured tissue showed substantially more platelet aggregation and occlusive platelet microthrombi in the capillaries of the damaged areas of the wild type mice than in those of the FcR gamma(-/-) mice. Platelet Syk was scarcely activated in the FcR gamma(-/-) mice after myocardial ischemia and reperfusion, but significantly activated in the FcR gamma(+/+) mice. CD11b expression on neutrophils was elevated after myocardial ischemia and reperfusion in both mouse groups, whereas myeloperoxidase activity in the injured areas was significantly lower in the FcRgamma(-/-) mice than in the FcRgamma(+/+) mice. These results suggest that the collagen-induced activation of platelets through the FcR gamma plays a pivotal role in the extension of myocardial ischemia-reperfusion injury. FcRgamma and GPVI may be important therapeutic targets for myocardial ischemia-reperfusion injury.

  13. [Molecular biology of haemostasis: fibrinogen, factor XIII].

    PubMed

    Meyer, M

    2004-05-01

    Genetic defects of fibrinogen are caused by a broad spectrum of mutations in one of the three structural genes FGA, FGB and FGG. They result in complete or partial lack of plasma fibrinogen (a- or hypofibrinogenaemia) or in structural abnormalities affecting protein function (dysfibrinogenaemia). In contrast to afibrinogenaemia mainly caused by nonsense, frameshift, and splice site mutations resulting in substantially truncated polypeptide chains (mainly Aalpha), in hypo- and dysfibrinogenaemias missense mutations lead to the exchange of single amino acids as dominating underlying defect. In the cases with quantitative disorders, bleeding with various degrees of severity is generally observed. Dysfibrinogenaemia is associated with both bleeding or thrombosis or even a combination of haemorrhagic and thromboembolic symptoms. About one half of the dysfibrinogenaemic cases is clinically asymptomatic. The plasmatic factor XIII (FXIII) is a heterotetramer composed of two A and two B subunits encoded by two different genes. FXIII deficiency is associated with bleeding, wound dehiscence and recurrent spontaneous abortions. The most frequent form is caused by defects in the A subunit with a broad spectrum of underlying mutations. Defects of the B subunit are very rare and were molecularly elucidated in only a few cases.

  14. 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

  15. Second harmonic generation in collagen

    NASA Astrophysics Data System (ADS)

    Reiser, Karen M.; Stoller, Patrick; Celliers, Peter; Rubenchik, Alexander; Bratton, Clay; Yankelevich, Diego

    2003-11-01

    Collagen possesses a strong second order nonlinear susceptibility; when it is irradiated with intense laser light, some of the reflected and transmitted light will have twice the frequency of the incident beam, a phenomenon known as second harmonic generation (SHG). Polarization modulation of an ultra-short pulse laser beam can be used to simultaneously measure collagen fiber orientation, SHG intensity, and a parameter related to the second order non-linear susceptibility. This technique has made it possible to discriminate among patterns of fibrillar orientation in many tissues. In the present study the role that organizational complexity plays in the relationship between nonlinear optical properties and collagen structure is investigated. As a component of tissues and organs, collagen"s structure and function is inextricably intertwined with that of the many other matrix components; to what extent do these noncollagenous components affect its nonlinear properties? To answer this, we investigated SHG in two different collagenous tissues, liver and cartilage; in addition we looked at the effect of progressive pathological changes in these tissues on SHG. At the other end of the spectrum, we studied collagen organized at the minimal level of complexity necessary for SHG detection: fibrils generated from solutions containing only a single type of collagen. Data obtained from these studies suggest that collagen"s strong nonlinear susceptibility, a property no other biologically significant macromolecule shares to the same degree, may serve as more than the basis of a novel imaging device for soft tissue. Collagen"s nonlinear optical properties in conjunction with its vast capacity for self-initiated conformational change--through self-assembly, site recognition, post-translational modification, and the like -make it an attractive candidate molecule for any of several demanding engineering applications, such as nanopatterning.

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

    PubMed

    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

    2016-04-01

    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 α(IIb)β3 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 α(IIb)β3 Markedly, in thrombi from mice deficient in transglutaminase factor XIII, platelet-driven fibrin formation and Rhod-A14 binding were abolished by blockage of integrin α(IIb)β3. Vice versa, star-like fibrin formation from platelets of a patient with deficiency in α(IIb)β3(Glanzmann thrombasthenia) was abolished upon blockage of transglutaminase activity. We conclude that coated platelets, with initial α(IIb)β3 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 α(IIb)β3.

  17. 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

  18. Speckle Interferometry at the US Naval Observatory. XIII

    DTIC Science & Technology

    2007-10-01

    SPECKLE INTERFEROMETRY AT THE US NAVAL OBSERVATORY. XIII. Brian D. Mason, William I. Hartkopf, Gary L. Wycoff, and Gary Wieder US Naval Observatory...was 185 yr, as HJ 729 was initially resolved by J. Herschel in 1820 ( Herschel 1829). The long delay in confirming these historic pairs was simply due...was first resolved by J. Herschel in 1827 ( Herschel 1870). The mean separation for the measurements presented in Tables 5 and 6 is 16.9700. A high

  19. A microtiter plate assay for factor XIII A-chain-fibrin interactions.

    PubMed

    Achyuthan, K E; Santiago, M A; Greenberg, C S

    1994-05-15

    Factor XIII A-chain-fibrin interactions regulate factor XIIIa formation and fibrin cross-linking. A microtiter plate assay was developed for studying these interactions. Microtiter plate wells were coated with fibrinogen and converted to fibrin by thrombin. After blocking the wells with bovine serum albumin, factor XIII A-chain was added and binding was monitored by incubating first with anti-factor XIII followed by anti-rabbit IgG-alkaline phosphatase. Enzymatic hydrolysis of p-nitrophenyl phosphate was quantitated by the absorbance at 405 nm. BInding was specific, sensitive, rapid, saturable, and reversible, requiring only nanograms of either factor XIII or fibrin. Binding was time- and concentration-dependent and independent of divalent cations. The bound material was identified as factor XIII A-chain by sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting. Factor XIII binding was inhibited > 75% by 250 mM sodium chloride or 250 nM anti-factor XIII IgG. The method was also suitable for demonstrating binding using 0.8% plasma or with r-factor XIII expressed in Saccharomyces cerevisiae or Escherichia coli. This method is suitable for identifying the binding sites that are important for plasma factor XIII activation and factor XIIIa activity.

  20. Collagen for bone tissue regeneration.

    PubMed

    Ferreira, Ana Marina; Gentile, Piergiorgio; Chiono, Valeria; Ciardelli, Gianluca

    2012-09-01

    In the last decades, increased knowledge about the organization, structure and properties of collagen (particularly concerning interactions between cells and collagen-based materials) has inspired scientists and engineers to design innovative collagen-based biomaterials and to develop novel tissue-engineering products. The design of resorbable collagen-based medical implants requires understanding the tissue/organ anatomy and biological function as well as the role of collagen's physicochemical properties and structure in tissue/organ regeneration. Bone is a complex tissue that plays a critical role in diverse metabolic processes mediated by calcium delivery as well as in hematopoiesis whilst maintaining skeleton strength. A wide variety of collagen-based scaffolds have been proposed for different tissue engineering applications. These scaffolds are designed to promote a biological response, such as cell interaction, and to work as artificial biomimetic extracellular matrices that guide tissue regeneration. This paper critically reviews the current understanding of the complex hierarchical structure and properties of native collagen molecules, and describes the scientific challenge of manufacturing collagen-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of innovative techniques for scaffold and material manufacturing that are currently opening the way to the preparation of biomimetic substrates that modulate cell interaction for improved substitution, restoration, retention or enhancement of bone tissue function.

  1. Impaired clot retraction in factor XIII A subunit-deficient mice.

    PubMed

    Kasahara, Kohji; Souri, Masayoshi; Kaneda, Mizuho; Miki, Toshiaki; Yamamoto, Naomasa; Ichinose, Akitada

    2010-02-11

    Factor XIII (FXIII) is a plasma transglutaminase that cross-links fibrin monomers, alpha(2)-plasmin inhibitor, and so forth. Congenital FXIII deficiency causes lifelong bleeding symptoms. To understand the molecular pathology of FXIII deficiency in vivo, its knockout mice have been functionally analyzed. Because prolonged bleeding times, a sign of defective/abnormal primary hemostasis, were commonly observed in 2 separate lines of FXIII A subunit (FXIII-A) knockout mice, a possible role or roles of FXIII in platelet-related function was investigated in the present study. Although platelet aggregation induced by adenosine diphosphate or collagen was normal, clot retraction (CR) was lost in the platelet-rich plasma (PRP) of FXIII-A knockout mice. In contrast, there was no CR impairment in the PRP of tissue transglutaminase-knockout mice compared with that of wild-type mice. Furthermore, a transglutaminase inhibitor, cystamine, halted CR in the PRP of wild-type mice. These results indicate that the enzymatic activity of FXIII is necessary for CR, at least in mice.

  2. Collagenous colitis.

    PubMed Central

    Kingham, J G; Levison, D A; Morson, B C; Dawson, A M

    1986-01-01

    Clinical and pathological aspects of six patients with collagenous colitis are presented. These patients have been observed for between four and 15 years and the evolution of the condition is documented in three (cases 1, 3 and 5). Management and possible pathogenetic mechanisms of this enigmatic condition are discussed. Images Fig. 1 Fig. 2 PMID:3699567

  3. Collagenous gastritis.

    PubMed

    Jin, Xiaoyi; Koike, Tomoyuki; Chiba, Takashi; Kondo, Yutaka; Ara, Nobuyuki; Uno, Kaname; Asano, Naoki; Iijima, Katsunori; Imatani, Akira; Watanabe, Mika; Shirane, Akio; Shimosegawa, Tooru

    2013-09-01

    In the present paper, we report a case of rare collagenous gastritis. The patient was a 25-year-old man who had experienced nausea, abdominal distention and epigastralgia since 2005. Esophagogastroduodenoscopy (EGD) carried out at initial examination by the patient's local doctor revealed an extensively discolored depression from the upper gastric body to the lower gastric body, mainly including the greater curvature, accompanied by residual mucosa with multiple islands and nodularity with a cobblestone appearance. Initial biopsies sampled from the nodules and accompanying atrophic mucosa were diagnosed as chronic gastritis. In August, 2011, the patient was referred to Tohoku University Hospital for observation and treatment. EGD at our hospital showed the same findings as those by the patient's local doctor. Pathological findings included a membranous collagen band in the superficial layer area of the gastric mucosa, which led to a diagnosis of collagenous gastritis. Collagenous gastritis is an extremely rare disease, but it is important to recognize its characteristic endoscopic findings to make a diagnosis.

  4. 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

    ... 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 Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units...

  5. 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

    ... 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 Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units...

  6. 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

    ... 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 Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units...

  7. 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

    ... 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 Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units...

  8. 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. PMID:27635271

  9. Fibrinogen, red blood cells, and factor XIII in venous thrombosis.

    PubMed

    Walton, B L; Byrnes, J R; Wolberg, A S

    2015-06-01

    Cardiovascular disease is the leading cause of death and disability worldwide. Among cardiovascular causes of death, venous thrombosis (VT) is ranked third most common in the world. Venous thrombi have high red blood cell and fibrin content; however, the pathophysiologic mechanisms that contribute to venous thrombus composition and stability are still poorly understood. This article reviews biological, biochemical, and biophysical contributions of fibrinogen, factor XIII, and red blood cells to VT, and new evidence suggesting interactions between these components mediate venous thrombus composition and size.

  10. 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.

  11. Fibrillar, fibril-associated and basement membrane collagens of the arterial wall: architecture, elasticity and remodeling under stress.

    PubMed

    Osidak, M S; Osidak, E O; Akhmanova, M A; Domogatsky, S P; Domogatskaya, A S

    2015-01-01

    The ability of a human artery to pass through 150 million liters of blood sustaining 2 billion pulsations of blood pressure with minor deterioration depends on unique construction of the arterial wall. Viscoelastic properties of this construction enable to re-seal the occuring damages apparently without direct immediate participance of the constituent cells. Collagen structures are considered to be the elements that determine the mechanoelastic properties of the wall in parallel with elastin responsible for elasticity and resilience. Collagen scaffold architecture is the function-dependent dynamic arrangement of a dozen different collagen types composing three distinct interacting forms inside the extracellular matrix of the wall. Tightly packed molecules of collagen types I, III, V provide high tensile strength along collagen fibrils but toughness of the collagen scaffold as a whole depends on molecular bonds between distinct fibrils. Apart of other macromolecules in the extracellular matrix (ECM), collagen-specific interlinks involve microfilaments of collagen type VI, meshwork-organized collagen type VIII, and FACIT collagen type XIV. Basement membrane collagen types IV, XV, XVIII and cell-associated collagen XIII enable transmission of mechanical signals between cells and whole artery matrix. Collagen scaffold undergoes continuous remodeling by decomposition promoted with MMPs and reconstitution from newly produced collagen molecules. Pulsatile stress-strain load modulates both collagen synthesis and MMP-dependent collagen degradation. In this way the ECM structure becomes adoptive to mechanical challenges. The mechanoelastic properties of the arterial wall are changed in atherosclerosis concomitantly with collagen turnover both type-specific and dependent on the structure. Improving the feedback could be another approach to restore sufficient blood circulation.

  12. A Novel Functional Role of Collagen Glycosylation

    PubMed Central

    Jürgensen, Henrik J.; Madsen, Daniel H.; Ingvarsen, Signe; Melander, Maria C.; Gårdsvoll, Henrik; Patthy, Laszlo; Engelholm, Lars H.; Behrendt, Niels

    2011-01-01

    Collagens make up the most abundant component of interstitial extracellular matrices and basement membranes. Collagen remodeling is a crucial process in many normal physiological events and in several pathological conditions. Some collagen subtypes contain specific carbohydrate side chains, the function of which is poorly known. The endocytic collagen receptor urokinase plasminogen activator receptor-associated protein (uPARAP)/Endo180 plays an important role in matrix remodeling through its ability to internalize collagen for lysosomal degradation. uPARAP/Endo180 is a member of the mannose receptor protein family. These proteins all include a fibronectin type II domain and a series of C-type lectin-like domains, of which only a minor part possess carbohydrate recognition activity. At least two of the family members, uPARAP/Endo180 and the mannose receptor, interact with collagens. The molecular basis for this interaction is known to involve the fibronectin type II domain but nothing is known about the function of the lectin domains in this respect. In this study, we have investigated a possible role of the single active lectin domain of uPARAP/Endo180 in the interaction with collagens. By expressing truncated recombinant uPARAP/Endo180 proteins and analyzing their interaction with collagens with high and low levels of glycosylation we demonstrated that this lectin domain interacts directly with glycosylated collagens. This interaction is functionally important because it was found to modulate the endocytic efficiency of the receptor toward highly glycosylated collagens such as basement membrane collagen IV. Surprisingly, this property was not shared by the mannose receptor, which internalized glycosylated collagens independently of its lectin function. This role of modulating its uptake efficiency by a specific receptor is a previously unrecognized function of collagen glycosylation. PMID:21768090

  13. ε-(γ-Glutamyl)lysine in Fibrin: Lack of Crosslink Formation in Factor XIII Deficiency

    PubMed Central

    Pisano, J. J.; Finlayson, J. S.; Peyton, Marjorie P.; Nagai, Yumiko

    1971-01-01

    Fibrin clots formed in normal plasma contained about 6 mol of ε-(γ-glutamyl)lysine per mol of fibrin, whereas those formed in plasma from individuals with Factor XIII deficiency contained little or none of this crosslink (0.02-0.64 mol/mol of fibrin). Partial supplementation of the plasma with Factor XIII, at a single concentration tested, commensurately increased the number of crosslinks. PMID:5279517

  14. 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.

  15. Probing multiscale mechanics of collagen with optical tweezers

    NASA Astrophysics Data System (ADS)

    Shayegan, Marjan; Rezaei, Naghmeh; Lam, Norman H.; Altindal, Tuba; Wieczorek, Andrew; Forde, Nancy R.

    2013-09-01

    How the molecular structure of the structural, extracellular matrix protein collagen correlates with its mechanical properties at different hierarchical structural levels is not known. We demonstrate the utility of optical tweezers to probe collagen's mechanical response throughout its assembly hierarchy, from single molecule force-extension measurements through microrheology measurements on solutions of collagen molecules, collagen fibrillar gels and gelatin. These experiments enable the determination of collagen's flexibility, mechanics, and timescales and strengths of interaction at different levels of hierarchy, information critical to developing models of how collagen's physiological function and stability are influenced by its chemical composition. By investigating how the viscoelastic properties of collagen are affected by the presence of telopeptides, protein domains that strongly influence fibril formation, we demonstrate that these play a role in conferring transient elasticity to collagen solutions.

  16. Structural insight for chain selection and stagger control in collagen

    PubMed Central

    Boudko, Sergei P.; Bächinger, Hans Peter

    2016-01-01

    Collagen plays a fundamental role in all known metazoans. In collagens three polypeptides form a unique triple-helical structure with a one-residue stagger to fit every third glycine residue in the inner core without disturbing the poly-proline type II helical conformation of each chain. There are homo- and hetero-trimeric types of collagen consisting of one, two or three distinct chains. Thus there must be mechanisms that control composition and stagger during collagen folding. Here, we uncover the structural basis for both chain selection and stagger formation of a collagen molecule. Three distinct chains (α1, α2 and α3) of the non-collagenous domain 2 (NC2) of type IX collagen are assembled to guide triple-helical sequences in the leading, middle and trailing positions. This unique domain opens the door for generating any fragment of collagen in its native composition and stagger. PMID:27897211

  17. Collagen-mediated hemostasis.

    PubMed

    Manon-Jensen, T; Kjeld, N G; Karsdal, M A

    2016-03-01

    Collagens mediate essential hemostasis by maintaining the integrity and stability of the vascular wall. Imbalanced turnover of collagens by uncontrolled formation and/or degradation may result in pathologic conditions such as fibrosis. Thickening of the vessel wall because of accumulation of collagens may lead to arterial occlusion or thrombosis. Thinning of the wall because of collagen degradation or deficiency may lead to rupture of the vessel wall or aneurysm. Preventing excessive hemorrhage or thrombosis relies on collagen-mediated actions. Von Willebrand factor, integrins and glycoprotein VI, as well as clotting factors, can bind collagen to restore normal hemostasis after trauma. This review outlines the essential roles of collagens in mediating hemostasis, with a focus on collagens types I, III, IV, VI, XV, and XVIII.

  18. 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.

  19. 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…

  20. 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…

  1. 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.

  2. Evidence for a Structural Requirement for the Aggregation of Platelets by Collagen

    PubMed Central

    Jaffe, Russell; Deykin, Daniel

    1974-01-01

    the minimal structural unit; and that cross-linkages within collagen do not play a critical role in platelet aggregation. Images PMID:4855862

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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... philosophy. The librarian or educational media specialist, with students and staff, shall set...

  9. 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...

  10. 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...

  11. 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...

  12. Play Therapy

    PubMed Central

    Kool, Ritesh

    2010-01-01

    Play therapy represents a unique form of treatment that is not only geared toward young children, but is translated into a language children can comprehend and utilize—the language of play. For the referring provider or practitioner, questions may remain regarding the nature, course, and efficacy of play therapy. This article reviews the theoretical underpinnings of play therapy, some practical considerations, and finally a summary of the current state of research in regard to play therapy. The authors present the practicing psychiatrist with a road map for referring a patient to play therapy or initiating it in appropriate cases. PMID:21103141

  13. 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.

  14. 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)

  15. Play Therapy

    PubMed Central

    Lawver, Timothy; Blankenship, Kelly

    2008-01-01

    Play therapy is a treatment modality in which the therapist engages in play with the child. Its use has been documented in a variety of settings and with a variety of diagnoses. Treating within the context of play brings the therapist and the therapy to the level of the child. By way of an introduction to this approach, a case is presented of a six-year-old boy with oppositional defiant disorder. The presentation focuses on the events and interactions of a typical session with an established patient. The primary issues of the session are aggression, self worth, and self efficacy. These themes manifest themselves through the content of the child’s play and narration of his actions. The therapist then reflects these back to the child while gently encouraging the child toward more positive play. Though the example is one of nondirective play therapy, a wide range of variation exists under the heading of play therapy. PMID:19724720

  16. Pathogenetic difference between collagen arthritis and adjuvant arthritis

    PubMed Central

    1984-01-01

    Daily treatment with cyclosporin at a dose of 25 mg/kg for 14 d gave complete suppression of the development of collagen arthritis and adjuvant arthritis in Sprague-Dawley rats during an observation period of 45 d. To study whether the immunologic unresponsiveness produced by cyclosporin is antigen specific, we rechallenged the cyclosporin- protected rats with either type II collagen or complete Freund's adjuvant (CFA) after discontinuation of cyclosporin treatment. Type II collagen-immunized, cyclosporin-protected rats did not develop arthritis in response to reimmunization with type II collagen, but, they did develop arthritis in response to a subsequent injection of CFA. Similarly, CFA-injected, cyclosporin-protected rats showed a suppressed arthritogenic reaction in response to reinjection of CFA, whereas their response to a subsequent immunization with type II collagen was unaffected. On the other hand, the rats that were treated with cyclosporin without any prior antigenic challenge could develop arthritis in response to a subsequent injection of CFA or type II collagen after cessation of cyclosporin treatment. These results indicate that specific immunologic unresponsiveness can be induced by cyclosporin in the two experimental models of polyarthritis, collagen arthritis and adjuvant arthritis, and that there is no cross-reactivity between type II collagen and the mycobacterial cell wall components. The results further indicate that immunity to type II collagen plays a critical role in the pathogenesis of collagen arthritis but that its pathogenetic role in adjuvant arthritis is insignificant. PMID:6201583

  17. Play Sheets. Let's Play! Project.

    ERIC Educational Resources Information Center

    State Univ. of New York, Buffalo. Center for Assistive Technology.

    This collection of play sheets 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 "low-tech" assistive technology. Each single page guide provides guidance to…

  18. The Role of Collagen Organization on the Properties of Bone.

    PubMed

    Garnero, Patrick

    2015-09-01

    Bone is a complex tissue constituted by a collagen matrix filled in with crystal of hydroxyapatite (HAP). Bone mechanical properties are influenced by the collagen matrix which is organized into hierarchical structures from the individual type I collagen heterotrimer flanked by linear telopeptides at each end to the collagen fibrils that are interconnected by enzymatic and non-enzymatic cross-links. Although most studies focused on the role of collagen cross-links in bone strength, other organizational features may also play a role. At the molecular level it has been shown that homotrimer of type I collagen found in bone tissue of some patients with osteogenesis imperfecta (OI) is characterized by decreased mechanical competence compared to the regular heterotrimer. The state of C-telopeptide isomerization-which can be estimated by the measurement in body fluids of the native and isomerized isoforms-has also been shown to be associated with bone strength, particularly the post-yield properties independent of bone size and bone mineral density. Other higher hierarchical features of collagen organization have shown to be associated with changes in bone mechanical behavior in ex vivo models and may also be relevant to explain bone fragility in diseases characterized by collagen abnormalities e.g., OI and Paget's disease. These include the orientation of collagen fibrils in a regular longitudinal direction, the D-spacing period between collagen fibrils and the collagen-HAP interfacial bonding. Preliminary data indicate that some of these organizational features can change during treatment with bisphosphonate, raloxifene, and PTH suggesting that they may contribute to their anti-fracture efficacy. It remains however to be determined which of these parameters play a specific and independent role in bone matrix properties, what is the magnitude of mechanical strength explained by collagen organization, whether they are relevant to explain osteoporosis-induced bone

  19. Control of Collagen Triple Helix Stability by Phosphorylation.

    PubMed

    Acevedo-Jake, Amanda M; Ngo, Daniel H; Hartgerink, Jeffrey D

    2017-03-10

    The phosphorylation of the collagen triple helix plays an important role in collagen synthesis, assembly, signaling, and immune response, although no reports detailing the effect this modification has on the structure and stability of the triple helix exist. Here we investigate the changes in stability and structure resulting from the phosphorylation of collagen. Additionally, the formation of pairwise interactions between phosphorylated residues and lysine is examined. In all tested cases, phosphorylation increases helix stability. When charged-pair interactions are possible, stabilization via phosphorylation can play a very large role, resulting inasmuch as a 13.0 °C increase in triple helix stability. Two-dimensional NMR and molecular modeling are used to study the local structure of the triple helix. Our results suggest a mechanism of action for phosphorylation in the regulation of collagen and also expand upon our understanding of pairwise amino acid stabilization of the collagen triple helix.

  20. Why Play?

    ERIC Educational Resources Information Center

    Weininger, O.

    This paper draws together briefly theories and knowledge from research in morphology and cognitive psychology, as well as some hypothetical information from traditional psychiatry, to show the ramifications of play in children's development. Play is defined as any of a wide variety of behaviors through which an individual attempts to discover what…

  1. Playful Gaming.

    ERIC Educational Resources Information Center

    Makedon, Alex

    1984-01-01

    Discusses the concept of playful gaming (an idea not expressed fully by either term alone) and uses it as an analytical tool to study the playfulness of games in the context of several social phenomena; i.e., social change, socialization, utopian systems, and educational gaming. An extensive reference list is provided. (MBR)

  2. Playing Shakespeare.

    ERIC Educational Resources Information Center

    Bashian, Kathleen Ryniker

    1993-01-01

    Describes a yearlong project at 12 Catholic middle schools in the Diocese of Arlington, Virginia, to incorporate the plays of William Shakespeare into the curriculum. Teachers attended university lectures and directed students in performances of the plays. Concludes that Shakespeare can be understood and enjoyed by middle school students. (BCY)

  3. 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…

  4. A novel functional role of collagen glycosylation: interaction with the endocytic collagen receptor uparap/ENDO180.

    PubMed

    Jürgensen, Henrik J; Madsen, Daniel H; Ingvarsen, Signe; Melander, Maria C; Gårdsvoll, Henrik; Patthy, Laszlo; Engelholm, Lars H; Behrendt, Niels

    2011-09-16

    Collagens make up the most abundant component of interstitial extracellular matrices and basement membranes. Collagen remodeling is a crucial process in many normal physiological events and in several pathological conditions. Some collagen subtypes contain specific carbohydrate side chains, the function of which is poorly known. The endocytic collagen receptor urokinase plasminogen activator receptor-associated protein (uPARAP)/Endo180 plays an important role in matrix remodeling through its ability to internalize collagen for lysosomal degradation. uPARAP/Endo180 is a member of the mannose receptor protein family. These proteins all include a fibronectin type II domain and a series of C-type lectin-like domains, of which only a minor part possess carbohydrate recognition activity. At least two of the family members, uPARAP/Endo180 and the mannose receptor, interact with collagens. The molecular basis for this interaction is known to involve the fibronectin type II domain but nothing is known about the function of the lectin domains in this respect. In this study, we have investigated a possible role of the single active lectin domain of uPARAP/Endo180 in the interaction with collagens. By expressing truncated recombinant uPARAP/Endo180 proteins and analyzing their interaction with collagens with high and low levels of glycosylation we demonstrated that this lectin domain interacts directly with glycosylated collagens. This interaction is functionally important because it was found to modulate the endocytic efficiency of the receptor toward highly glycosylated collagens such as basement membrane collagen IV. Surprisingly, this property was not shared by the mannose receptor, which internalized glycosylated collagens independently of its lectin function. This role of modulating its uptake efficiency by a specific receptor is a previously unrecognized function of collagen glycosylation.

  5. 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.

  6. Collagen vascular disease

    MedlinePlus

    ... developed these disorders were previously said to have "connective tissue" or "collagen vascular" disease. We now have names ... be used. These include as undifferentiated systemic rheumatic (connective tissue) diseases or overlap syndromes. Images Dermatomyositis, heliotrope eyelids ...

  7. [Condition setting for the measurement of blood coagulation factor XIII activity using a fully automated blood coagulation analyzer, COAGTRON-350].

    PubMed

    Kanno, Nobuko; Kaneko, Makoto; Tanabe, Kumiko; Jyona, Masahiro; Yokota, Hiromitsu; Yatomi, Yutaka

    2012-12-01

    The automated laboratory analyzer COAGTRON-350 (Trinity Biotech) is used for routine and specific coagulation testing for the detection of fibrin formation utilizing either mechanical principles (ball method) or photo-optical principles, chromogenic kinetic enzyme analysis, and immune-turbidimetric detection systems in one benchtop unit. In this study, we demonstrated and established a parameter for the measurement of factor XIII (FXIII) activity using Berichrom FXIII reagent and the COAGTRON-350 analyzer. The usual protocol used for this reagent, based on the handling method, was slightly modified for this device. The analysis showed that fundamental study for the measurement of FXIII activity under our condition setting was favorable in terms of reproducibility, linearity, and correlation with another assays. Since FXIII is the key enzyme that plays important roles in hemostasis by stabilizing fibrin formation, the measurement of FXIII is essential for the diagnosis of bleeding disorders. Therefore, FXIII activity assessment as well as a routine coagulation testing can be conducted simultaneously with one instrument, which is useful in coagulopathy assessment.

  8. 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

  9. Evidence of independent evolution of genotype XIII Newcastle disease viruses in India.

    PubMed

    Das, Moushumee; Kumar, Sachin

    2017-04-01

    Despite the prevalence of Newcastle disease virus (NDV) outbreaks in India through the decades, there has been little genetic characterisation of the virulent strains circulating in Northeast India. In 2014, a poultry farm in the Kamrup district of Assam reported an ND outbreak. In this study, genetic analysis and clinicopathological tests showed the virulent nature of the isolate Kamrup. Based on prudent classification criteria, the virulent strain Kamrup was found to be most closely related to members of genotype XIII of class II NDV. A phylogenetic analysis of NDV strains suggested three sub-genotypes: XIIIa, XIIIb and XIIIc. NDV strain Kamrup belonged to sub-genotype XIIIc. Sub-genotype XIIIc isolates were similar to the 1982 isolate from cockatoo and appeared to have evolved parallel to the preceding genotype XIII viruses circulating in India. The high genetic diversity and frequency of mutations observed in the envelope glycoproteins of strain Kamrup demonstrate the evolution of the pandemic genotype XIII NDV in India, which further undermines and complicates of NDV management in India.

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

    PubMed

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

    2013-08-14

    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, (1)H-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.

  11. 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…

  12. 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…

  13. 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…

  14. Development of multifunctional collagen scaffolds directed by collagen mimetic peptides

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Lan (Allen)

    Collagen is widely used for soft tissue replacement and tissue engineering scaffold. Functionalized collagen may offer new and improved applications for collagen-based biomaterials. But passively adsorbed molecules readily diffuse out from collagen matrix, and conventional chemical reactions on collagen are difficult to control and may compromise the biochemical feature of natural collagen. Hence, the aim of this dissertation is to develop a new physical collagen modification method through the non-covalent immobilization of collagen mimetic peptides (CMPs) and CMP derivatives on collagen scaffolds, thereby evading the drawbacks of passive and chemical modifications. Most of the research on CMPs over the past three decades has focused on synthesizing CMPs and understanding the effects of amino acid sequence on the peptide structural stability. Although few attempts have been made to develop biomaterials based on pure CMP, CMP has never used in complex with natural collagen. We demonstrate that CMPs with varying chain lengths have strong propensity to associate with natural 2-D and 3-D collagen substrates. We also show that CMPs can recognize and bind to reconstituted type I collagen fibers as well as collagens of ex vivo human liver tissue. The practical use of CMPs conjugated with linear and multi-arm poly(ethylene glycol)s allows to control cell organization in 2-D collagen substrates. Our cell adhesion studies suggest that under certain conditions (e.g. high incubation temperature, small CMP size), the bound CMP derivatives can be released from the collagen matrix, which may provide new opportunities for manipulating cell behavior especially by dynamically controlling the amount of signaling molecules in the collagen matrix. Polyanionic charged CMP was synthesized to modulate tubulogenesis of endothelial cells by attracting VEGF with 3-D collagen gel and a new PEG hydrogel using bifunctional CMP conjugates was synthesized as physico-chemical crosslinkers for

  15. Collagen fibrils: nanoscale ropes.

    PubMed

    Bozec, Laurent; van der Heijden, Gert; Horton, Michael

    2007-01-01

    The formation of collagen fibrils from staggered repeats of individual molecules has become "accepted" wisdom. However, for over thirty years now, such a model has failed to resolve several structural and functional questions. In a novel approach, it was found, using atomic force microscopy, that tendon collagen fibrils are composed of subcomponents in a spiral disposition-that is, their structure is similar to that of macroscale ropes. Consequently, this arrangement was modeled and confirmed using elastic rod theory. This work provides new insight into collagen fibril structure and will have wide application-from the design of scaffolds for tissue engineering and a better understanding of pathogenesis of diseases of bone and tendon, to the conservation of irreplaceable parchment-based museum exhibits.

  16. 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.

  17. Structure and function of collagen types

    SciTech Connect

    Mayne, R.; Burgeson, R.E.

    1987-01-01

    This book contains 10 chapters. Some of the chapter titles are: The Classical Collagens: Types I, II, and III; Type IV Collagen; Type IX Collagen; and Analysis of Collagen Structure by Molecular Biology Techniques.

  18. [The genetics of collagen diseases].

    PubMed

    Kaplan, J; Maroteaux, P; Frezal, J

    1986-01-01

    Heritable disorders of collagen include Ehler-Danlos syndromes (11 types are actually known), Larsen syndrome and osteogenesis imperfecta. Their clinical, genetic and biochemical features are reviewed. Marfan syndrome is closely related to heritable disorders of collagen.

  19. 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.

  20. 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.

  1. Serotonin (5-HT) inhibits Factor XIII-A-mediated plasma fibronectin matrix assembly and crosslinking in osteoblast cultures via direct competition with transamidation.

    PubMed

    Cui, Cui; Kaartinen, Mari T

    2015-03-01

    Serotonin (5-HT)--a monoamine with a variety of physiological functions--has recently emerged as a major regulator of bone mass. 5-HT is synthesized in the brain and the gut, and gut-derived 5-HT contributes to circulating 5-HT levels and is a negative modulator of bone mass and quality. 5-HT's negative effects on the skeleton are considered to be mediated via its receptors and transporter in osteoblasts and osteoclasts; however, 5-HT can also incorporate covalently into proteins via a transglutaminase-mediated serotonylation reaction, which in turn can alter protein function. Plasma fibronectin (pFN)--a major component of the bone extracellular matrix that regulates bone matrix quality in vivo--is a major transglutaminase substrate in bone and in osteoblast cultures. We have recently demonstrated that pFN assembly into osteoblast culture matrix requires a Factor XIII-A (FXIII-A) transglutaminase-mediated crosslinking step that regulates both quantity and quality of type I collagen matrix in vitro. In this study, we show that 5-HT interferes with pFN assembly into the extracellular matrix in osteoblast cultures, which in turn has major consequences on matrix assembly and mineralization. 5-HT treatment of MC3T3-E1 osteoblast cultures dramatically decreased both pFN fibrillogenesis as analyzed by immunofluorescence microscopy and pFN levels in DOC-soluble and DOC-insoluble matrix fractions. This was accompanied by an increase in pFN levels in the culture media. Analysis of the media showed covalent incorporation of 5-HT into pFN. Minor co-localization of pFN with 5-HT was also seen in extracellular fibrils. 5-HT also showed co-localization with FXIII-A on the cell surface and inhibited its transamidation activity directly. 5-HT treatment of osteoblast cultures resulted in a discontinuous pFN matrix and impaired type I collagen deposition, decreased alkaline phosphatase and lysyl oxidase activity, and delayed mineralization of the cultures. Addition of excess

  2. 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

  3. 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.

  4. Dirac R-matrix calculation for electron-impact excitation of S xiii

    NASA Astrophysics Data System (ADS)

    Li, F.; Liang, G. Y.; Bari, M. A.; Zhao, G.

    2013-08-01

    Context. Sulfur emission lines in the soft X-ray and extreme-ultraviolet regions are observed in a variety of laboratory and astrophysical spectra. But accurate electron impact excitation data for S xiii for state-of-the-art NLTE spectral models are scarce. Aims: We calculated electron-impact excitation collision strengths and effective collision strengths of S xiii for transitions among the lowest-lying 98 fine-structure states 1s22lnl' corresponding to principal quantum numbers n = 2,3,4. The effective collision strengths for these transitions were computed over a wide temperature range (log 10Te (K) = 4.53-7.53) for various astrophysical plasma conditions. Methods: We used the fully-relativistic parallel Dirac R-matrix code to calculate collision strengths. To generate target wavefunctions and energy levels for scattering calculations, we employed the GRASP0 multi-configuration Dirac-Fock code for states up to n = 5. Results: The wavefunctions are generated from 27 configurations - 1s22lnl'(n = 2,3,4,5) - giving rise to 166 jj energy levels. The collision and effective collision strengths among the lowest 98 fine-structure levels are compared with the previous theoretical calculations. The collision strengths for most transitions agree well at higher incident electron energies. Conclusions: The resonant contributions to effective collision strengths are most dominant at lower temperatures.

  5. Dirac R-matrix calculations of photoionization cross sections of Ni XII and atomic structure data of Ni XIII

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s23p5 (^2P^o3/2,1/2) levels and 12 excited states of Ni XII using relativistic Dirac Atomic R-matrix Codes (DARC) across the photon energy range between the ionizations thresholds of the corresponding states and well above the thresholds of the last level of the Ni XIII target ion. Generally, a good agreement is obtained between our results and the earlier theoretical photoionization cross sections. Moreover, we have used two independent fully relativistic GRASP and FAC codes to calculate fine-structure energy levels, wavelengths, oscillator strengths, transitions rates among the lowest 48 levels belonging to the configuration (3s23p4, 3s3p5, 3p6, 3s23p33d) in Ni XIII. Additionally, radiative lifetimes of all the excited states of Ni XIII are presented. Our results of the atomic structure of Ni XIII show good agreement with other theoretical and experimental results available in the literature. A good agreement is found between our calculated lifetimes and the experimental ones. Our present results are useful for plasma diagnostic of fusion and astrophysical plasmas.

  6. 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

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

  7. 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).

  8. UV damage of collagen: insights from model collagen peptides.

    PubMed

    Jariashvili, Ketevan; Madhan, Balaraman; Brodsky, Barbara; Kuchava, Ana; Namicheishvili, Louisa; Metreveli, Nunu

    2012-03-01

    Fibrils of Type I collagen in the skin are exposed to ultraviolet (UV) light and there have been claims that collagen photo-degradation leads to wrinkles and may contribute to skin cancers. To understand the effects of UV radiation on collagen, Type I collagen solutions were exposed to the UV-C wavelength of 254 nm for defined lengths of time at 4°C. Circular dichroism (CD) experiments show that irradiation of collagen leads to high loss of triple helical content with a new lower thermal stability peak and SDS-gel electrophoresis indicates breakdown of collagen chains. To better define the effects of UV radiation on the collagen triple-helix, the studies were extended to peptides which model the collagen sequence and conformation. CD studies showed irradiation for days led to lower magnitudes of the triple-helix maximum at 225 nm and lower thermal stabilities for two peptides containing multiple Gly-Pro-Hyp triplets. In contrast, the highest radiation exposure led to little change in the T(m) values of (Gly-Pro-Pro)(10) and (Ala-Hyp-Gly)(10) , although (Gly-Pro-Pro)(10) did show a significant decrease in triple helix intensity. Mass spectroscopy indicated preferential cleavage sites within the peptides, and identification of some of the most susceptible sites of cleavage. The effect of radiation on these well defined peptides gives insight into the sequence and conformational specificity of photo-degradation of collagen.

  9. 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.

  10. 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.

  11. 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.

  12. Cryptic Peptides from Collagen: A Critical Review.

    PubMed

    Banerjee, Pradipta; Shanthi, C

    2016-01-01

    Collagen, a predominant structural protein in extracellular matrix (ECM), is now considered to have probable roles in many biological activities and hence, in different forms have found application as nutraceutical or pharmaceutical therapy option. Many of the biological properties are believed to be due to small hidden peptide residues in the collagen molecules, which come into play after the biodegradation or biosorption of the parent molecule. These peptide regions are called cryptic peptides or by some, as cryptides. The proteolytic hydrolysis of the ECM protein releases the cryptic peptides with many novel biological activities not exhibited directly by the parental protein which include angiogenic, antimicrobial, mitogenic and chemotactic properties. The research for understanding the role of these cryptic peptide regions and making use of them in medical field is very active. Such an understanding could lead to the development of peptide supplements for many biomedical applications. The prolific research in this area is reviewed in this paper.

  13. 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.

  14. Biological role of prolyl 3-hydroxylation in type IV collagen.

    PubMed

    Pokidysheva, Elena; Boudko, Sergei; Vranka, Janice; Zientek, Keith; Maddox, Kerry; Moser, Markus; Fässler, Reinhard; Ware, Jerry; Bächinger, Hans Peter

    2014-01-07

    Collagens constitute nearly 30% of all proteins in our body. Type IV collagen is a major and crucial component of basement membranes. Collagen chains undergo several posttranslational modifications that are indispensable for proper collagen function. One of these modifications, prolyl 3-hydroxylation, is accomplished by a family of prolyl 3-hydroxylases (P3H1, P3H2, and P3H3). The present study shows that P3H2-null mice are embryonic-lethal by embryonic day 8.5. The mechanism of the unexpectedly early lethality involves the interaction of non-3-hydroxylated embryonic type IV collagen with the maternal platelet-specific glycoprotein VI (GPVI). This interaction results in maternal platelet aggregation, thrombosis of the maternal blood, and death of the embryo. The phenotype is completely rescued by producing double KOs of P3H2 and GPVI. Double nulls are viable and fertile. Under normal conditions, subendothelial collagens bear the GPVI-binding sites that initiate platelet aggregation upon blood exposure during injuries. In type IV collagen, these sites are normally 3-hydroxylated. Thus, prolyl 3-hydroxylation of type IV collagen has an important function preventing maternal platelet aggregation in response to the early developing embryo. A unique link between blood coagulation and the ECM is established. The newly described mechanism may elucidate some unexplained fetal losses in humans, where thrombosis is often observed at the maternal/fetal interface. Moreover, epigenetic silencing of P3H2 in breast cancers implies that the interaction between GPVI and non-3-hydroxylated type IV collagen might also play a role in the progression of malignant tumors and metastasis.

  15. Collagenous colitis: an unrecognised entity.

    PubMed Central

    Bogomoletz, W V; Adnet, J J; Birembaut, P; Feydy, P; Dupont, P

    1980-01-01

    A patient is reported with chronic abdominal pain, diarrhoea, and associated radiological and endoscopic abnormalities of the sigmoid colon. Light and electron microscopic study of colorectal mucosa showed abnormal collagenous thickening of the subepithelial basement membrane. The authors felt that the clinical and morphological features justified a diagnosis of collagenous colitis. Review of the literature suggested that collagenous colitis was still an unrecognised entity. Images Fig. 1 Fig. 2 Fig. 3 PMID:7380341

  16. Si XIII and Si XIV line emission search with the ANS crystal spectrometer

    NASA Technical Reports Server (NTRS)

    Parsignault, D. R.; Delvaille, J. P.; Epstein, A.; Grindlay, J. E.; Schnopper, H. W.

    1978-01-01

    The final results of the search for Si XIII and Si XIV line emission, using the ANS Bragg crystal spectrometer, are presented. No positive line detection was achieved in any of the measurements made on several types of cosmic object; i.e., a transient X-ray source, close binary systems, supernova remnants, GX sources, and clusters of galaxies. Three-sigma upper limits for discrete line emission from these objects are reported and compared with line strengths inferred from other proportional-counter and Bragg spectrometer data. The present upper limit of 1.0 eV for the equivalent width of a narrow Si XIV line emission from the X-ray nova A0620-00 is an order of magnitude lower than previous limits set by other experiments.

  17. 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

  18. 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.

  19. 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.

  20. Mechanical Properties of Single Collagen Fibrils Revealed by Force Spectroscopy

    NASA Astrophysics Data System (ADS)

    Graham, John; Phillips, Charlotte; Grandbois, Michel

    2004-03-01

    In the field of biomechanics, collagen fibrils are believed to be robust mechanical structures characterized by a low extensibility. Until very recently, information on the mechanical properties of collagen fibrils could only be derived from ensemble measurements performed on complete tissues such as bone, skin and tendon. Here we measure force-elongation/relaxation profiles of single collagen fibrils using atomic force microscopy-based force spectroscopy. The elongation profiles indicate that in vitro assembled heterotrimeric type I collagen fibrils are characterized by a large extensibility. Numerous discontinuities and a plateau in the force profile indicate major reorganization occurs within the fibrils in the 1.5 -- 4.5 nN range. Our study demonstrates that newly assembled collagen fibrils are robust structures with a significant reserve of elasticity that could play a determinant role in cellular motion in the context of tissue growth and morphogenesis. In contrast, homotrimeric collagen fibrils corresponding to osteogenesis imperfecta pathology exhibit a marked difference in their elasticity profile.

  1. Collagen-binding proteins of Streptococcus mutans and related streptococci.

    PubMed

    Avilés-Reyes, A; Miller, J H; Lemos, J A; Abranches, J

    2017-04-01

    The ability of Streptococcus mutans to interact with collagen through the expression of collagen-binding proteins (CBPs) bestows this oral pathogen with an alternative to the sucrose-dependent mechanism of colonization classically attributed to caries development. Based on the abundance and distribution of collagen throughout the human body, stringent adherence to this molecule grants S. mutans with the opportunity to establish infection at different host sites. Surface proteins, such as SpaP, WapA, Cnm and Cbm, have been shown to bind collagen in vitro, and it has been suggested that these molecules play a role in colonization of oral and extra-oral tissues. However, robust collagen binding is not achieved by all strains of S. mutans, particularly those that lack Cnm or Cbm. These observations merit careful dissection of the contribution from these different CBPs towards tissue colonization and virulence. In this review, we will discuss the current understanding of mechanisms used by S. mutans and related streptococci to colonize collagenous tissues, and the possible contribution of CBPs to infections in different sites of the host.

  2. 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

  3. Meprin β contributes to collagen deposition in lung fibrosis

    PubMed Central

    Biasin, V.; Wygrecka, M.; Marsh, L. M.; Becker-Pauly, C.; Brcic, L.; Ghanim, B.; Klepetko, W.; Olschewski, A.; Kwapiszewska, G.

    2017-01-01

    Lung fibrosis is a severe disease characterized by epithelial cell injury, inflammation and collagen deposition. The metalloproteases meprinα and meprinβ have been shown to enhance collagen maturation and inflammatory cell infiltration via cleavage of cell-cell contact molecules; therefore we hypothesized that meprins could play a role in lung fibrosis. An exhaustive characterization of bleomycin-treated meprinα, meprinβ and the double meprinsαβ knock-out (KO) with respective wt-littermates was performed by using several different methods. We observed no difference in lung function parameters and no change in inflammatory cells infiltrating the lung between wt and all meprins KO mice after 14 days bleomycin. No difference in epithelial integrity as assessed by e-cadherin protein level was detected in bleomycin-treated lungs. However, morphological analysis in the bleomycin-treated mice revealed decrease collagen deposition and tissue density in meprinβ KO, but not in meprinα and meprinαβ KO mice. This finding was accompanied by localization of meprinβ to epithelial cells in regions with immature collagen in mice. Similarly, in human IPF lungs meprinβ was mostly localized in epithelium. These findings suggest that local environment triggers meprinβ expression to support collagen maturation. In conclusion, our data demonstrate the in vivo relevance of meprinβ in collagen deposition in lung fibrosis. PMID:28059112

  4. Gel-spinning of mimetic collagen and collagen/nano-carbon fibers: Understanding multi-scale influences on molecular ordering and fibril alignment.

    PubMed

    Green, Emily C; Zhang, Yiying; Li, Heng; Minus, Marilyn L

    2017-01-01

    Synthetic gel-spun collagen and collagen/nano-carbon fibers were found to exhibit structural mimicry comparable to native tendons. X-ray scattering and microscopy analyses are used to characterize the molecular and fibrillar alignment in the synthetic fibers, where D-banding is observed throughout the spun fibers - consistent with native collagen. For the composite collagen/nano-carbon fibers, the morphology and dispersion quality of the nano-carbons within was found to play a significant role in influencing collagen molecular ordering and fibril alignment. Fibrillar and molecular alignment was also better preserved during elongation of the composites as compared to the control collagen fibers. These results show the structural influence of a rigid inclusion on the collagen fibril structure. Both dry- and wet-state tensile testing were performed on the collagen fibers, and these results show behavior comparable to the native materials. Dry-state tests also reveal interfacial interaction between the nano-fillers and the collagen fibrils through theoretical analysis. Wet-state tensile testing indicates the structure-property behavior of the mimetic hierarchical structure within the synthetic fibers.

  5. 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.

  6. 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.

  7. 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.

  8. Binding of Clostridium perfringens to collagen correlates with the ability to cause necrotic enteritis in chickens.

    PubMed

    Wade, B; Keyburn, A L; Seemann, T; Rood, J I; Moore, R J

    2015-11-18

    This study investigated the ability of Clostridium perfringens isolates derived from chickens to bind to collagen types I-V and gelatin. In total 21 strains from three distinct backgrounds were studied: (i) virulent strains isolated from birds suffering from necrotic enteritis, (ii) avirulent strains isolated from birds suffering from necrotic enteritis and (iii) strains isolated from healthy birds. All strains isolated from diseased birds had been assessed for virulence in a disease induction model. The virulent isolates all displayed collagen binding ability. However, most strains in the other two classes showed negligible binding to collagen. The prevalence of a previously described C. perfringens putative collagen adhesin-encoding gene was investigated by PCR screening. It was found that five of the strains carried the putative collagen adhesin-encoding gene and that all of these strains were virulent isolates. Based on these studies it is postulated that collagen adhesion may play a role in the pathogenesis of necrotic enteritis.

  9. Immunohistochemical localization of collagen type XI alpha1 and alpha2 chains in human colon tissue.

    PubMed

    Bowen, Kara B; Reimers, Aaron P; Luman, Sarah; Kronz, Joseph D; Fyffe, William E; Oxford, Julia Thom

    2008-03-01

    In previous studies, collagen XI mRNA has been detected in colon cancer, but its location in human colon tissue has not been determined. The heterotrimeric collagen XI consists of three alpha chains. While it is known that collagen XI plays a regulatory role in collagen fibril formation, its function in the colon is unknown. The characterization of normal human colon tissue will allow a better understanding of the variance of collagen XI in abnormal tissues. Grossly normal and malignant human colon tissue was obtained from pathology archives. Immunohistochemical staining with a 58K Golgi marker and alpha1(XI) and alpha2(XI) antisera was used to specifically locate their presence in normal colon tissue. A comparative bright field microscopic analysis showed the presence of collagen XI in human colon. The juxtanuclear, dot-like collagen XI staining in the Golgi apparatus of goblet cells in normal tissue paralleled the staining of the 58K Golgi marker. Ultra light microscopy verified these results. Staining was also confirmed in malignant colon tissue. This study is the first to show that collagen XI is present in the Golgi apparatus of normal human colon goblet cells and localizes collagen XI in both normal and malignant tissue. Although the function of collagen XI in the colon is unknown, our immunohistochemical characterization provides the foundation for future immunohistopathology studies of the colon.

  10. 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.

  11. Recurrent Post Tonsillectomy Secondary Hemorrhage in Patients with Factor XIII Deficiency: A Case Series and Review of Literature

    PubMed Central

    ALtamimi, Zaid Abu Rajab; Sheikh, Rashid; Omar, Hassen; Taweel, Hayam Al; Ganesan, Shanmugam

    2016-01-01

    Case series Patients: Male, 20 • Male, 4 • Male, 27 • Male, 25 • Female, 5 • Female, 26 Final Diagnosis: Post tonsillectomy secondary hemorrhage Symptoms: Bleeding • bleeding per oral Medication: — Clinical Procedure: Control of post tonsillectomy secondary hemorrhage Specialty: Otolaryngology Objective: Rare disease Background: Post-tonsillectomy hemorrhage (PTH) has been reported in the literature as a serious complication after tonsillectomy that has high morbidity and can be life threatening. In cases of recurrent secondary PTH, one should consider coagulopathies as the hidden pathology. Factor XIII deficiency is very rare, suggested to be present 1 in 2 million people. Patients with undiagnosed factor XIII deficiency with secondary PTH are extremely rare. Case Report: We report on the cases of six patients (four adults and two children) who presented with recurrent attacks of secondary PTH. Conclusion: Recurrent, severe PTH could be related to undiagnosed hematological disorders. PMID:27843132

  12. Collagen binding to Staphylococcus aureus

    SciTech Connect

    Holderbaum, D.; Hall, G.S.; Ehrhart, L.A.

    1986-11-01

    Staphylococcus aureus can bind soluble collagen in a specific, saturable manner. We have previously shown that some variability exists in the degree of collagen binding between different strains of heat-killed, formaldehyde-fixed S. aureus which are commercially available as immunologic reagents. The present study demonstrates that live S. aureus of the Cowan 1 strain binds amounts of collagen per organism equivalent to those demonstrated previously in heat-killed, formaldehyde-fixed bacteria but has an affinity over 100 times greater, with Kd values of 9.7 X 10(-11) M and 4.3 X 10(-8) M for live and heat-killed organisms, respectively. Studies were also carried out with S. aureus killed by ionizing radiation, since this method of killing the organism seemed less likely to alter the binding moieties on the surface than did heat killing. Bacteria killed by exposure to gamma radiation bound collagen in a manner essentially indistinguishable from that of live organisms. Binding of collagen to irradiated cells of the Cowan 1 strain was rapid, with equilibrium reached by 30 min at 22 degrees C, and was fully reversible. The binding was not inhibited by fibronectin, fibrinogen, C1q, or immunoglobulin G, suggesting a binding site for collagen distinct from those for these proteins. Collagen binding was virtually eliminated in trypsin-treated organisms, indicating that the binding site has a protein component. Of four strains examined, Cowan 1 and S. aureus ATCC 25923 showed saturable, specific binding, while strains Woods and S4 showed a complete lack of binding. These results suggest that some strains of S. aureus contain high-affinity binding sites for collagen. While the number of binding sites per bacterium varied sixfold in the two collagen-binding strains, the apparent affinity was similar.

  13. 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.

  14. Clinical uses of collagen shields.

    PubMed

    Poland, D E; Kaufman, H E

    1988-09-01

    Collagen shields immersed in tobramycin solution for one minute were applied to one eye each of 60 patients who had had cataract extraction, penetrating keratoplasty, or epikeratophakia or who had nonsurgical epithelial healing problems. The shields were well tolerated; one patient had the shield removed and one patient lost the shield in the early postoperative period. The surgical patients showed more rapid healing of epithelial defects after surgery with the use of the collagen shield. Patients with acute nonsurgical epithelial problems, such as contact lens abrasions and recurrent erosion, responded to the use of the collagen shield with improved healing. Patients with chronic epithelial defects responded poorly, presumably because underlying abnormalities in Bowman's layer prevented epithelial growth in the area of the defect. No infections were noted in any of the patients. The collagen shields appear to promote enhanced healing in patients with postsurgical and acute epithelial defects and to provide adequate antibiotic prophylaxis against infection in these vulnerable eyes.

  15. 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

  16. Collagen organization in canine myxomatous mitral valve disease: an x-ray diffraction study.

    PubMed

    Hadian, Mojtaba; Corcoran, Brendan M; Han, Richard I; Grossmann, J Günter; Bradshaw, Jeremy P

    2007-10-01

    Collagen fibrils, a major component of mitral valve leaflets, play an important role in defining shape and providing mechanical strength and flexibility. Histopathological studies show that collagen fibrils undergo dramatic changes in the course of myxomatous mitral valve disease in both dogs and humans. However, little is known about the detailed organization of collagen in this disease. This study was designed to analyze and compare collagen fibril organization in healthy and lesional areas of myxomatous mitral valves of dogs, using synchrotron small-angle x-ray diffraction. The orientation, density, and alignment of collagen fibrils were mapped across six different valves. The findings reveal a preferred collagen alignment in the main body of the leaflets between two commissures. Qualitative and quantitative analysis of the data showed significant differences between affected and lesion-free areas in terms of collagen content, fibril alignment, and total tissue volume. Regression analysis of the amount of collagen compared to the total tissue content at each point revealed a significant relationship between these two parameters in lesion-free but not in affected areas. This is the first time this technique has been used to map collagen fibrils in cardiac tissue; the findings have important applications to human cardiology.

  17. Characterization of the correlation between collagen fibril thickness and forward and backward second harmonic signal

    NASA Astrophysics Data System (ADS)

    Hsueh, Chiu-Mei; Hovhannisyan, Vladimir A.; Dong, Chen-Yuan

    2011-07-01

    Optical-based microscopy plays an important role in various scientific fields such as physics, chemistry and biology. Second harmonic generation (SHG) microscopy has become one of the indispensable tools for biomedical imaging for the last decade because the signal generated from SHG is sensitive to the objective structure and this amazing non-invasive method can also directly observe the objective without using extra fluorescent labels, especially for collagen molecules. As the most abundant protein in animals, collagen is responsible for a number of important structural and functional roles in vertebrates. For certain diseases, it has been shown that collagen fiber diameter has a significant variation and thus as a vital symptom for diagnosis. Moreover, collagen diameter is also a key parameter for fibrogenesis studying. Therefore, the determination of collagen fiber diameter is important for studying biophysical processes and identifying bioengineering applications. In this study, we investigated various collagen fibril thicknesses and the corresponding forward (FSHG) and backward (BSHG) second harmonic signal intensity variation. Our result exhibits that SHG intensity can quantify describe the relative collagen fibril thickness alteration, which also indicates the coherent effect difference between FSHG and BSHG. This approach demonstrates the capability of SHG imaging in providing collagen mechanical information and that may be applied in the evaluation of advancing collagen issues in vivo.

  18. Regulation of collagen fibrillogenesis by cell-surface expression of kinase dead DDR2.

    PubMed

    Blissett, Angela R; Garbellini, Derek; Calomeni, Edward P; Mihai, Cosmin; Elton, Terry S; Agarwal, Gunjan

    2009-01-23

    The assembly of collagen fibers, the major component of the extracellular matrix (ECM), governs a variety of physiological processes. Collagen fibrillogenesis is a tightly controlled process in which several factors, including collagen binding proteins, have a crucial role. Discoidin domain receptors (DDR1 and DDR2) are receptor tyrosine kinases that bind to and are phosphorylated upon collagen binding. The phosphorylation of DDRs is known to activate matrix metalloproteases, which in turn cleave the ECM. In our earlier studies, we established a novel mechanism of collagen regulation by DDRs; that is, the extracellular domain (ECD) of DDR2, when used as a purified, soluble protein, inhibits collagen fibrillogenesis in-vitro. To extend this novel observation, the current study investigates how the DDR2-ECD, when expressed as a membrane-anchored, cell-surface protein, affects collagen fibrillogenesis by cells. We generated a mouse osteoblast cell line that stably expresses a kinase-deficient form of DDR2, termed DDR2/-KD, on its cell surface. Transmission electron microscopy, fluorescence microscopy, and hydroxyproline assays demonstrated that the expression of DDR2/-KD reduced the rate and abundance of collagen deposition and induced significant morphological changes in the resulting fibers. Taken together, our observations extend the functional roles that DDR2 and possibly other membrane-anchored, collagen-binding proteins can play in the regulation of cell adhesion, migration, proliferation and in the remodeling of the extracellular matrix.

  19. Comparative studies of type X collagen expression in normal and rachitic chicken epiphyseal cartilage

    PubMed Central

    1989-01-01

    The levels of type X collagen in mineralizing normal chicken epiphyses and nonmineralizing rachitic chicken tibial epiphyses were measured and compared. Qualitative immunoperoxidase studies with anti-chick type X collagen monoclonal antibodies on sections from normal and rachitic cartilage demonstrated that the type X collagen levels in rachitic growth plates are reduced. Northern hybridization of mRNA and biosynthetic studies have confirmed that type X collagen synthesis in rickets is also decreased. In hypocalcemic rickets, the level of type X collagen mRNA is reduced by 80% whereas the level of type X collagen mRNA is only reduced by 50% in normocalcemic rickets. These observations provide additional evidence that type X collagen is involved in the process of cartilage mineralization and also suggest that the partial recovery of type X collagen synthesis in normocalcemic rickets may be related to the elevated plasma concentration of calcium. Calcium concentration may therefore play an important role in the control of type X collagen synthesis. PMID:2477383

  20. Heterogeneous force network in 3D cellularized collagen networks.

    PubMed

    Liang, Long; Jones, Christopher; Chen, Shaohua; Sun, Bo; Jiao, Yang

    2016-10-25

    Collagen networks play an important role in coordinating and regulating collective cellular dynamics via a number of signaling pathways. Here, we investigate the transmission of forces generated by contractile cells in 3D collagen-I networks. Specifically, the graph (bond-node) representations of collagen networks with collagen concentrations of 1, 2 and 4 mg ml(-1) are derived from confocal microscopy data and used to model the network microstructure. Cell contraction is modeled by applying correlated displacements at specific nodes of the network, representing the focal adhesion sites. A nonlinear elastic model is employed to characterize the mechanical behavior of individual fiber bundles including strain hardening during stretching and buckling under compression. A force-based relaxation method is employed to obtain equilibrium network configurations under cell contraction. We find that for all collagen concentrations, the majority of the forces are carried by a small number of heterogeneous force chains emitted from the contracting cells, which is qualitatively consistent with our experimental observations. The force chains consist of fiber segments that either possess a high degree of alignment before cell contraction or are aligned due to fiber reorientation induced by cell contraction. The decay of the forces along the force chains is significantly slower than the decay of radially averaged forces in the system, suggesting that the fibreous nature of biopolymer network structure can support long-range force transmission. The force chains emerge even at very small cell contractions, and the number of force chains increases with increasing cell contraction. At large cell contractions, the fibers close to the cell surface are in the nonlinear regime, and the nonlinear region is localized in a small neighborhood of the cell. In addition, the number of force chains increases with increasing collagen concentration, due to the larger number of focal adhesion sites

  1. Heterogeneous force network in 3D cellularized collagen networks

    NASA Astrophysics Data System (ADS)

    Liang, Long; Jones, Christopher; Chen, Shaohua; Sun, Bo; Jiao, Yang

    2016-12-01

    Collagen networks play an important role in coordinating and regulating collective cellular dynamics via a number of signaling pathways. Here, we investigate the transmission of forces generated by contractile cells in 3D collagen-I networks. Specifically, the graph (bond-node) representations of collagen networks with collagen concentrations of 1, 2 and 4 mg ml-1 are derived from confocal microscopy data and used to model the network microstructure. Cell contraction is modeled by applying correlated displacements at specific nodes of the network, representing the focal adhesion sites. A nonlinear elastic model is employed to characterize the mechanical behavior of individual fiber bundles including strain hardening during stretching and buckling under compression. A force-based relaxation method is employed to obtain equilibrium network configurations under cell contraction. We find that for all collagen concentrations, the majority of the forces are carried by a small number of heterogeneous force chains emitted from the contracting cells, which is qualitatively consistent with our experimental observations. The force chains consist of fiber segments that either possess a high degree of alignment before cell contraction or are aligned due to fiber reorientation induced by cell contraction. The decay of the forces along the force chains is significantly slower than the decay of radially averaged forces in the system, suggesting that the fibreous nature of biopolymer network structure can support long-range force transmission. The force chains emerge even at very small cell contractions, and the number of force chains increases with increasing cell contraction. At large cell contractions, the fibers close to the cell surface are in the nonlinear regime, and the nonlinear region is localized in a small neighborhood of the cell. In addition, the number of force chains increases with increasing collagen concentration, due to the larger number of focal adhesion sites

  2. Factor XIII deficiency in Iran: a comprehensive review of the literature.

    PubMed

    Dorgalaleh, Akbar; Naderi, Majid; Hosseini, Maryam Sadat; Alizadeh, Shaban; Hosseini, Soudabeh; Tabibian, Shadi; Eshghi, Peyman

    2015-04-01

    Factor XIII deficiency (FXIIID) is a rare bleeding disorder with an estimated prevalence of 1 in 2-million population worldwide. In Iran, a Middle Eastern country with a high rate of consanguineous marriages, there are approximately 473 patients afflicted with FXIIID. An approximately 12-fold higher prevalence of FXIIID is estimated in Iran in comparison with overall worldwide frequency. In this study, we have undertaken a comprehensive review on different aspects of FXIIID in the Iranian population. The distribution of this disease in different regions of Iran reveals that Sistan and Baluchestan Province has not only the highest number of patients with FXIIID in Iran but the highest global incidence of this condition. Among Iranian patients, umbilical cord bleeding, hematoma, and prolonged wound bleeding are the most frequent clinical manifestations. There are several disease causing mutations in Iranian patients with FXIIID, with Trp187Arg being the most common mutation in FXIIID in Iran. Traditionally, the management of FXIIID in Iran was only based on administration of fresh frozen plasma or cryoprecipitate, until 2009 when FXIII concentrate became available for patient management. Various studies have evaluated the efficacy and safety of prophylactic regimens in different situations with valuable findings. Although the focus of this study is on Iran, it offers considerable insight into FXIIID, which can be applied more extensively to improve the management and quality of life in all affected patients.

  3. 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

  4. Emission Lines of Fe XI - XIII in the Extreme Ultraviolet Region

    NASA Astrophysics Data System (ADS)

    Lepson, Jaan; Beiersdorfer, Peter; Liedahl, Duane; Desai, Priya; Brickhouse, Nancy; Dupree, Andrea; Kahn, Steven

    2009-05-01

    Iron is one of the most abundant heavy elements in extreme ultraviolet spectra of astrophysical and laboratory plasmas, and its various ions radiate profusely in the extreme ultraviolet (EUV) wavelength band. Iron emission in the EUV provides important d iagnostic tools for such properties as plasma temperature and density, and perhaps even magnetic field strength. Despite its importance to astrophysics and magnetic fusion, knowledge of the EUV spectrum of iron is incomplete. Identification of iron emis sion lines is hampered by the paucity of accurate laboratory measurements and the uncertainty of even the best atomic models. As part of a project to measure and compile emission line data in the EUV, we present here spectra and lines of Fe XI - XIII recorded on the Livermore EBIT-II electron beam ion trap in the 50 - 120 åregion. We measured line positions to 0.02 åand relative intensities with an accuracy of one part in twenty. Many new lines are identified and added to the available databa ses. Part of this work was performed under the auspices of the U S Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by NASA's Astronomy and Physics Research and Analysis Program under Con t ract NNH07AF811.

  5. On the reconstructing the coronal magnetic field from Fe XIII 10747 A emission line observations

    NASA Astrophysics Data System (ADS)

    Kramar, M.; Lin, H.; Inhester, B.

    2009-12-01

    Magnetic fields in the solar corona are the dominant fields that determine the static and dynamic properties of this outermost region of the solar atmosphere. It is within this tenuous region that the magnetic force dominates the gas pressure. Direct measurement of the coronal magnetic field is one of the most challenging problems in observational solar astronomy. To date, one of the promising measurement methods that have been successfully demonstrated is the spectropolarimetric measurement of the Fe XIII 10747 A forbidden emission line (CEL) (Lin, Penn, Tomczyk 2000; Lin, Kuhn, Coulter 2004; Tomczyk et al. 2007) formed due to Hanle and Zeeman effects. However, because coronal measurements are integrated over line-of-site (LOS), it is impossible to derive the configuration of the coronal magnetic field from a single observation (from a single viewing direction). Recent development in vector tomography techniques based on IR forbidden CEL polarization measurements from several viewing direction (Kramar, Inhester, Solanki 2006; Kramar, Inhester 2007) has the potential to resolve the 3D coronal magnetic field structure. In this paper, we will present a study of the effects of instrumental characteristics on the results of vector tomographic inversion using simulated data. We also investigate the sensitivity of the vector tomographic inversion to different coronal magnetic field configuration.

  6. Safety of Factor XIII Concentrate: Analysis of More than 20 Years of Pharmacovigilance Data

    PubMed Central

    Solomon, Cristina; Korte, Wolfgang; Fries, Dietmar; Pendrak, Inna; Joch, Christine; Gröner, Albrecht; Birschmann, Ingvild

    2016-01-01

    Background Plasma-derived factor XIII (FXIII) concentrate is an effective treatment for FXIII deficiency. We describe adverse drug reactions (ADRs) reported during pharmacovigilance monitoring of Fibrogammin®/Corifact® and review published safety data. Methods Postmarketing safety reports recorded by CSL Behring from June 1993 to September 2013 were analyzed. Clinical studies published during the same period were also reviewed. Results Commercial data indicated that 1,653,450,333 IU FXIII concentrate were distributed over the review period, equivalent to 1,181,036 doses for a 70 kg patient. 75 cases were reported (one/15,700 standard doses or 22,046,000 IU). Reports of special interest included 12 cases of possible hypersensitivity reactions (one/98,400 doses or 137,787,500 IU), 7 with possible thromboembolic events (one/168,700 doses or 236,207,200 IU), 5 of possible inhibitor development (one/236,200 doses or 330,690,100 IU), and 20 of possible pathogen transmission (one/59,100 doses or 82,672,500 IU). 19 pathogen transmission cases involved viral infection; 4 could not be analyzed due to insufficient data, but for all others a causal relationship to the product was assessed as unlikely. A review of published literature revealed a similar safety profile. Conclusion Assessment of ADRs demonstrated that FXIII concentrate carries a low risk of ADRs across various clinical situations, suggesting a favorable safety profile. PMID:27781024

  7. 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

  8. Electromechanical properties of dried tendon and isoelectrically focused collagen hydrogels.

    PubMed

    Denning, D; Abu-Rub, M T; Zeugolis, D I; Habelitz, S; Pandit, A; Fertala, A; Rodriguez, B J

    2012-08-01

    Assembling artificial collagenous tissues with structural, functional, and mechanical properties which mimic natural tissues is of vital importance for many tissue engineering applications. While the electro-mechanical properties of collagen are thought to play a role in, for example, bone formation and remodeling, this functional property has not been adequately addressed in engineered tissues. Here the electro-mechanical properties of rat tail tendon are compared with those of dried isoelectrically focused collagen hydrogels using piezoresponse force microscopy under ambient conditions. In both the natural tissue and the engineered hydrogel D-periodic type I collagen fibrils are observed, which exhibit shear piezoelectricity. While both tissues also exhibit fibrils with parallel orientations, Fourier transform analysis has revealed that the degree of parallel alignment of the fibrils in the tendon is three times that of the dried hydrogel. The results obtained demonstrate that isoelectrically focused collagen has similar structural and electro-mechanical properties to that of tendon, which is relevant for tissue engineering applications.

  9. Biological effect of hydrolyzed collagen on bone metabolism.

    PubMed

    Daneault, Audrey; Prawitt, Janne; Fabien Soulé, Véronique; Coxam, Véronique; Wittrant, Yohann

    2017-06-13

    Osteoporosis is a chronic and asymptomatic disease characterized by low bone mass and skeletal microarchitectural deterioration, increased risk of fracture, and associated comorbidities most prevalent in the elderly. Due to an increasingly aging population, osteoporosis has become a major health issue requiring innovative disease management. Proteins are important for bone by providing building blocks and by exerting specific regulatory function. This is why adequate protein intake plays a considerable role in both bone development and bone maintenance. More specifically, since an increase in the overall metabolism of collagen can lead to severe dysfunctions and a more fragile bone matrix and because orally administered collagen can be digested in the gut, cross the intestinal barrier, enter the circulation, and become available for metabolic processes in the target tissues, one may speculate that a collagen-enriched diet provides benefits for the skeleton. Collagen-derived products such as gelatin or hydrolyzed collagen (HC) are well acknowledged for their safety from a nutritional point of view; however, what is their impact on bone biology? In this manuscript, we critically review the evidence from literature for an effect of HC on bone tissues in order to determine whether HC may represent a relevant alternative in the design of future nutritional approaches to manage osteoporosis prevention.

  10. 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.

  11. Biochemical changes in the collagenous matrix of osteoporotic avian bone.

    PubMed Central

    Knott, L; Whitehead, C C; Fleming, R H; Bailey, A J

    1995-01-01

    No detailed biochemical analysis has been carried out of the compositional changes in the collagen matrix of avian bone in relation to increased bone fragility in osteoporosis. We have shown that osteoporosis in avian bone is certainly not just a simple loss of apatite and collagen, but involves significant changes in the biochemistry of the collagen molecule and consequently in the physical properties of the fibre. The decreased mechanical strength and the change in the thermal stability can be directly related to changes in post-translational modifications, i.e. lysine hydroxylation and the intermolecular cross-link profile. The increased hydroxylation and change in cross-linking are consistent with increased turnover of the collagen, possibly in an attempt to initiate a repair mechanism which, in fact, leads to an acceleration in the increase in fragility of the bone. Clearly there are post-translational modifications of the newly synthesized collagen in avian osteoporosis, and these changes may play a role in the pathogenesis of the disease. Images Figure 1 PMID:7575401

  12. Comparative analysis of the structure and thermal stability of sea urchin peristome and rat tail tendon collagen.

    PubMed

    Mayne, Janice; Robinson, John J

    2002-01-01

    We have purified collagen from two distinct sources; the vertebrate, rat tail tendon and an invertebrate, sea urchin adult tissue, the peristome. The collagenous nature of the purification products was confirmed by amino acid compositional analysis. Both preparations had high contents of glycine and proline residues and hydroxyproline was also present. The total pyrrolidine (proline+hydroxyproline) content decreased from 17.9 mole% in rat tail collagen to 12.9 mole% in peristome collagen. Distinctly different circular dichroic spectra were measured for these collagens. Analyses of spectra, measured as a function of temperature, revealed distinct thermal denaturation profiles. The melting temperature for rat tail collagen was 38.5 degrees C, while the corresponding value for peristome collagen was significantly lower at 27 degrees C. A similar thermal denaturation profile was obtained for rat tail collagen in digestion experiments using a 41-kDa gelatinase activity, isolated from sea urchin eggs. These results identify structural differences between a typical, vertebrate type I fibrillar collagen and an echinoderm collagen which serves as a constituent of a mutable connective tissue. These differences may relate to the functional roles played by collagen in these distinctly different tissues.

  13. 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.

  14. 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.

  15. 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…

  16. Hydroperoxide formation in model collagens and collagen type I.

    PubMed

    Madison, S A; McCallum, J E B; Rojas Wahl, R U

    2002-02-01

    Protein hydroperoxides represent a relatively new concept in understanding biological oxidation chemistry. Here, we show with post-column-chemiluminescence that this sometimes remarkably stable and yet reactive species can be formed in collagen models and collagen type I when submitted to oxidative stress as exemplified by the Fenton reaction. These findings are supported by mass spectrometry and iodometry. Using (Proline-hydroxyproline-glycine)(10) (POG)(10), those hydroperoxides are stable for hours at room temperature and can give rise to free radicals in the presence of ferrous sulphate, as evidenced by EPR spin trapping with DMPO. Possible implications for biological systems are discussed with emphasis on collagen in the extracellular matrix in skin as a major type of connective tissue.

  17. The Role of Collagen Quaternary Structure in the Platelet:Collagen Interaction

    PubMed Central

    Brass, Lawrence F.; Bensusan, Howard B.

    1974-01-01

    We have investigated whether collagen queternary structure is required for the platelet: collagen interaction. Quaternary structure refers to the assembly of collagen monomers (tropocollagen) into polymers (native-type fibrils). Purified monomeric collagen was prepared from acetic acid extracts of fetal calfskin. Polymeric collagen was prepared by dispersion of bovine Achilles tendon collagen and by incubation of monomeric collagen at 37°C and pH 7.4. The state of polymerization was confirmed by electron microscopy. Release of platelet serotonin in the absence of platelet aggregation was used to determine the effectiveness of the platelet: collagen interaction. All forms of collagen produced serotonin release only after a lag period, but polymeric collagen gave a shorter lag period than did monomeric collagen. Monomeric collagen was also quanidinated selectively to convert collagen lysine groups to homoarginine, while leaving the arrangement of polar groups intact. Guanidination of monomeric collagen increased the rate of polymerization and reduced the lag time in serotonin release. Glucosamine (17 mM) retarded polymerization and inhibited the release of platelet serotonin by monomeric collagen but had little effect on release produced by thrombin or polymeric collagen. At the same concentration, glucosamine did not reduce the sensitivity of platelets to stimulation by collagen or block the platelet: collagen interaction. The only effect of glucosamine was on the collagen: collagen interaction. Galactosamine had a similar effect, but glucose, galactose, and N-acetylglycosamine had no effect. We conclude from this data that collagen monomers cannot effectively interact with platelets and that, therefore, collagen quaternary structure has a role in the recognition of collagen by platelets. PMID:4215825

  18. Mandibular Cartilage Collagen Network Nanostructure

    PubMed Central

    Vanden Berg-Foels, Wendy S.

    2015-01-01

    Background Mandibular condyle cartilage (MCC) has a unique structure among articular cartilages; however, little is known about its nanoscale collagen network architecture, hampering design of regeneration therapies and rigorous evaluation of regeneration experiment outcomes in preclinical research. Helium ion microscopy is a novel technology with a long depth of field that is uniquely suited to imaging open 3D collagen networks at multiple scales without obscuring conductive coatings. Objective The objective of this research was to image, at the micro- and nanoscales, the depth-dependent MCC collagen network architecture. Design MCC was collected from New Zealand white rabbits. Images of MCC zones were acquired using helium ion, transmission electron, and light microscopy. Network fibril and canal diameters were measured. Results For the first time, the MCC was visualized as a 3D collagen fibril structure at the nanoscale, the length scale of network assembly. Fibril diameters ranged from 7 to 110 nm and varied by zone. The articular surface was composed of a fine mesh that was woven through thin layers of larger fibrils. The fibrous zone was composed of approximately orthogonal lamellae of aligned fibrils. Fibrocyte processes surrounded collagen bundles forming extracellular compartments. The proliferative, mature, and hypertrophic zones were composed of a branched network that was progressively remodeled to accommodate chondrocyte hypertrophy. Osteoid fibrils were woven around osteoblast cytoplasmic processes to create numerous canals similar in size to canaliculi of mature bone. Conclusion This multiscale investigation advances our foundational understanding of the complex, layered 3D architecture of the MCC collagen network. PMID:27375843

  19. 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.

  20. 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

  1. 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

  2. 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

  3. Type IV Collagen is a Novel DEJ Biomarker that is Reduced by Radiotherapy

    PubMed Central

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

    2014-01-01

    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

  4. 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.

  5. Genetic Factors Influencing Coagulation Factor XIII B-Subunit Contribute to Risk of Ischemic Stroke

    PubMed Central

    Traylor, Matthew; Hysi, Pirro G.; Bevan, Stephen; Dichgans, Martin; Rothwell, Peter M.; Worrall, Bradford B.; Seshadri, Sudha; Sudlow, Cathie; Williams, Frances M.K.; Markus, Hugh S.; Lewis, Cathryn M.

    2015-01-01

    Background and Purpose— Abnormal coagulation has been implicated in the pathogenesis of ischemic stroke, but how this association is mediated and whether it differs between ischemic stroke subtypes is unknown. We determined the shared genetic risk between 14 coagulation factors and ischemic stroke and its subtypes. Methods— Using genome-wide association study results for 14 coagulation factors from the population-based TwinsUK sample (N≈2000 for each factor), meta-analysis results from the METASTROKE consortium ischemic stroke genome-wide association study (12 389 cases, 62 004 controls), and genotype data for 9520 individuals from the WTCCC2 ischemic stroke study (3548 cases, 5972 controls—the largest METASTROKE subsample), we explored shared genetic risk for coagulation and stroke. We performed three analyses: (1) a test for excess concordance (or discordance) in single nucleotide polymorphism effect direction across coagulation and stroke, (2) an estimation of the joint effect of multiple coagulation-associated single nucleotide polymorphisms in stroke, and (3) an evaluation of common genetic risk between coagulation and stroke. Results— One coagulation factor, factor XIII subunit B (FXIIIB), showed consistent effects in the concordance analysis, the estimation of polygenic risk, and the validation with genotype data, with associations specific to the cardioembolic stroke subtype. Effect directions for FXIIIB-associated single nucleotide polymorphisms were significantly discordant with cardioembolic disease (smallest P=5.7×10−04); the joint effect of FXIIIB-associated single nucleotide polymorphisms was significantly predictive of ischemic stroke (smallest P=1.8×10−04) and the cardioembolic subtype (smallest P=1.7×10−04). We found substantial negative genetic covariation between FXIIIB and ischemic stroke (rG=−0.71, P=0.01) and the cardioembolic subtype (rG=−0.80, P=0.03). Conclusions— Genetic markers associated with low FXIIIB levels

  6. 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…

  7. Children's Play and Television.

    ERIC Educational Resources Information Center

    Powell, Mark

    2001-01-01

    Discusses adverse effects of FCC deregulation of children's television programming on children's play behavior. Discusses the difference between play and imitation, the role of high quality dramatic play in healthy child development, the popularity of war play, and use of toys to increase dramatic play. Considers ways to help children gain control…

  8. 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.

  9. 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.

  10. 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.

  11. Evidence for a role of collagen synthesis in arterial smooth muscle cell migration.

    PubMed Central

    Rocnik, E F; Chan, B M; Pickering, J G

    1998-01-01

    Migration of smooth muscle cells (SMCs) and collagen synthesis by SMCs are central to the pathophysiology of vascular disease. Both processes can be induced shortly after vascular injury; however, a functional relationship between them has not been established. In this study, we determined if collagen synthesis was required for SMC migration, using ethyl-3,4-dihydroxybenzoate (EDHB), an inhibitor of prolyl-4-hydroxylase, and 3,4-DL-dehydroproline (DHP), a proline analogue, which we demonstrate inhibit collagen elaboration by porcine arterial SMCs. SMCs exposed to EDHB or DHP attached normally to collagen- and vitronectin-coated substrates; however, spreading on collagen but not vitronectin was inhibited. SMC migration speed, quantified by digital time-lapse video microscopy, was significantly and reversibly reduced by EDHB and DHP. Flow cytometry revealed that expression of beta1 integrins, through which SMCs interact with collagen, was unaffected by EDHB or DHP. However, both inhibitors prevented normal clustering of beta1 integrins on the surface of SMCs, consistent with a lack of appropriate matrix ligands for integrin engagement. Moreover, there was impaired recruitment of vinculin into focal adhesion complexes of spreading SMCs and disassembly of the smooth muscle alpha-actin-containing cytoskeleton. These findings suggest that de novo collagen synthesis plays a role in SMC migration and implicates a mechanism whereby newly synthesized collagen may be necessary to maintain the transcellular traction system required for effective locomotion. PMID:9576753

  12. 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.

  13. Collagen crosslinks in chondromalacia of the patella.

    PubMed

    Väätäinen, U; Kiviranta, I; Jaroma, H; Arokosi, J; Tammi, M; Kovanen, V

    1998-02-01

    The aim of the study was to determine collagen concentration and collagen crosslinks in cartilage samples from chondromalacia of the patella. To study the extracellular matrix alterations associated to chondromalacia, we determined the concentration of collagen (hydroxyproline) and its hydroxylysylpyridinoline and lysylpyridinoline crosslinks from chondromalacia foci of the patellae in 12 patients and 7 controls from apparently normal cadavers. The structure of the collagen network in 8 samples of grades II-IV chondromalacia was examined under polarized light microscopy. The full-thickness cartilage samples taken with a surgical knife from chondromalacia lesions did not show changes in collagen, hydroxylysylpyridinoline and lysylpyridinoline concentration as compared with the controls. Polarized light microscopy showed decreased birefringence in the superficial cartilage of chondromalacia lesions, indicating disorganization or disappearance of collagen fibers in this zone. It is concluded that the collagen network shows gradual disorganization with the severity of chondromalacia lesion of the patella without changes in the concentration or crosslinks of collagen.

  14. [Disc electrophoresis of collagen protein (author's transl)].

    PubMed

    Reitmayr, P; Verzár, F

    1975-01-01

    The composition of proteins extracted from tendon collagen is investigated by disc electrophoresis. No qualitative differences can be demonstrated between young and old collagen. The action of formaldehyde and methionine on the tendons has no effect on the electrophoretic picture.

  15. 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.

  16. 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.

  17. 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

  18. The materials science of collagen.

    PubMed

    Sherman, Vincent R; Yang, Wen; Meyers, Marc A

    2015-12-01

    Collagen is the principal biopolymer in the extracellular matrix of both vertebrates and invertebrates. It is produced in specialized cells (fibroblasts) and extracted into the body by a series of intra and extracellular steps. It is prevalent in connective tissues, and the arrangement of collagen determines the mechanical response. In biomineralized materials, its fraction and spatial distribution provide the necessary toughness and anisotropy. We review the structure of collagen, with emphasis on its hierarchical arrangement, and present constitutive equations that describe its mechanical response, classified into three groups: hyperelastic macroscopic models based on strain energy in which strain energy functions are developed; macroscopic mathematical fits with a nonlinear constitutive response; structurally and physically based models where a constitutive equation of a linear elastic material is modified by geometric characteristics. Viscoelasticity is incorporated into the existing constitutive models and the effect of hydration is discussed. We illustrate the importance of collagen with descriptions of its organization and properties in skin, fish scales, and bone, focusing on the findings of our group.

  19. 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.

  20. 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…

  1. 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.

  2. 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.

  3. The collagenous gastroenteritides: similarities and differences.

    PubMed

    Gopal, Purva; McKenna, Barbara J

    2010-10-01

    Collagenous gastritis, collagenous sprue, and collagenous colitis share striking histologic similarities and occur together in some patients. They also share some drug and disease associations. Pediatric cases of collagenous gastritis, however, lack most of these associations. The etiologies of the collagenous gastroenteritides are not known, so it is not clear whether they are similar because they share pathogeneses, or because they indicate a common histologic response to varying injuries. The features, disease and drug associations, and the inquiries into the pathogenesis of these disorders are reviewed.

  4. Collagen I confers gamma radiation resistance.

    PubMed

    Azorin, E; González-Martínez, P R; Azorin, J

    2012-12-01

    The effect of collagen on the response of somatomammotroph tumor cells (GH3) to gamma, radiation therapy was studied in vitro. After incubating confluent GH3 cell monolayers in a serum-free, maintaining medium, either with or without collagen, the monolayers were irradiated with 137Cs, gamma radiation. Collagen reduces cell mortality via ERK1/2 activation, abolishing gamma radiation, cell death, and promotes cell invasion when acting in synergy with collagen and in association with the, MAPK/ERK1/2 signaling pathway activation. The presence of collagen in somatomammotroph tumors, confers resistance to radiation.

  5. Collagen: a network for regenerative medicine

    PubMed Central

    Pawelec, K. M.; Best, S. M.

    2016-01-01

    The basic building block of the extra-cellular matrix in native tissue is collagen. As a structural protein, collagen has an inherent biocompatibility making it an ideal material for regenerative medicine. Cellular response, mediated by integrins, is dictated by the structure and chemistry of the collagen fibers. Fiber formation, via fibrillogenesis, can be controlled in vitro by several factors: pH, ionic strength, and collagen structure. After formation, fibers are stabilized via cross-linking. The final bioactivity of collagen scaffolds is a result of both processes. By considering each step of fabrication, scaffolds can be tailored for the specific needs of each tissue, improving their therapeutic potential. PMID:27928505

  6. Paradoxical effects of cyclosporin A on collagen arthritis in rats

    PubMed Central

    1983-01-01

    The effect of the immunosuppressive agent cyclosporin A (CS-A) on collagen arthritis in Sprague-Dawley rats is investigated. A 14-d course of CS-A treatment at doses of 15 mg/kg per day or more, begun on the same day as type II collagen immunization, suppressed the development of arthritis as well as humoral and delayed-type hypersensitivity (DTH) skin test responses to type II collagen, possibly by interfering with helper T cells. Additional studies demonstrated that CS-A treatment only during the induction phase of immunity proved to be successful. When CS-A treatment was started only during the immediately preclinical phase of arthritis or after the disease onset, a significant enhancement of the disease was obtained in a dose-dependent manner. This enhancement was accompanied by an augmentation of DTH skin reactions, while antibody responses were either suppressed or unaffected. These results appear to be attributable at least in part to a suppressive effect of CS-A on a population of suppressor T cells, thus resulting in a T cell-mediated helper effect. It is therefore reasonable to assume that the paradoxical effects of CS-A on collagen arthritis in rats might be caused by an altering of the sensitive balance of the two regulatory subpopulations of T cells. It is also possible that cell-mediated immune responses may play an important role in influencing the course of the disease. PMID:6644238

  7. 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

  8. 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".

  9. 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.

  10. 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

  11. Detection and identification of the heterogeneous novel subgroup 16SrXIII-(A/I)I phytoplasma associated with strawberry green petal disease and Mexican periwinkle virescence.

    PubMed

    Pérez-López, Edel; Dumonceaux, Tim J

    2016-11-01

    Phytoplasmas (species of the genus 'CandidatusPhytoplasma') are insect-vectored phytopathogenic bacteria associated with economically and ecologically important crop diseases. Strawberry production represents an important part of agricultural activity in Mexico and elsewhere, and infection of plants with phytoplasma renders the fruit inedible by altering plant development, resulting in virescence and phyllody. In this study we examined samples taken from four strawberry plants showing symptoms associated with strawberry green petal disease and from two periwinkle plants showing virescence, sampled in different areas of Mexico. Analysis of the 16S rRNA-encoding sequences showed that the plants were infected with a phytoplasma previously identified as Mexican periwinkle virescence (MPV; 16SrXIII). Examination of bacterial sequences from these samples revealed that two distinct 16S rRNA gene sequences were present in each sample along with a single chaperonin-60 (cpn60) sequence and a single rpoB sequence, suggesting that this strain displays 16S rRNA gene sequence heterogeneity. Two distinct rrn operons, identified with subgroup 16SrXIII-A and the newly described subgroup 16SrXIII-I, were identified from the six samples analyzed, delineating the novel subgroup 16SrXIII-(A/I)I, following the nomenclature proposed for heterogeneous subgroups.

  12. Activation of hageman factor by collagen

    PubMed Central

    Wilner, G. D.; Nossel, H. L.; LeRoy, E. C.

    1968-01-01

    Purified acid-soluble and insoluble human collagen accelerated the clotting of plateletpoor plasma in silicone-treated tubes. The clot-promoting effect did not appear to be due to thromboplastic activity since the collagen preparations did not activate factor X in the presence of factor VII and calcium. Instead, collagen appeared to accelerate clotting by activating Hageman factor (factor XII) on the basis of the following findings: collagen increased the clot-promoting activity of partially purified Hageman factor but exerted no further effect in the presence of kaolin, a known activator of Hageman factor; clot-promoting eluates were obtained from collagen exposed to normal, hemophilic, or PTC-deficient plasma but not from collagen exposed to Hageman or PTA-deficient plasma. The collagen molecule itself appeared to be required for the clot-promoting activity since digestion with collagenase or thermal denaturation at pH 2.5 (about 35°C) resulted in very marked reduction in clot-promoting activity. Since thermal denaturation is associated with transformation of collagen structure from triple helical to random coil form, it is suggested that the native form of collagen is essential for the ability to activate Hageman factor. Blockage of the free amino groups by treatment with nitrous acid or dinitrofluorobenzene only slightly reduced the clot-promoting activity of collagen. In contrast, since addition of cationic proteins to collagen markedly reduced pro-coagulant activity it is suggested that negatively charged sites on the collagen molecule are critical for Hageman factor activation. This suggestion is supported by the finding that pepsin treatment of collagen, which removes the predominantly negatively charged telopeptides, results in significant decrease in coagulant activity. Esterification of collagen, which neutralizes 80-90% of the free carboxyl groups, reduced coagulant activity by over 90% and it is suggested that the free carboxyl groups of glutamic and

  13. Playing It Right

    ERIC Educational Resources Information Center

    Tooley, Kay

    1973-01-01

    Described is one technique, referred to as "playing it right," to aid the therapist in the treatment of borderline children. "Playing it right" is based on the introduction of reality rules into the fantasy world of the borderline child. (CS)

  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. 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.

  16. Protective effect of Withania somnifera (Solanaceae) on collagen glycation and cross-linking.

    PubMed

    Babu, Pon Velayutham Anandh; Gokulakrishnan, Adikesavan; Dhandayuthabani, Rajendra; Ameethkhan, Dowlath; Kumar, Chandrasekara Vimal Pradeep; Ahamed, Md Iqbal Niyas

    2007-06-01

    Modification of collagen such as non-enzymatic glycation and cross-linking plays an important role in diabetic complications and age-related diseases. We evaluate the effect of Withania somnifera on glucose-mediated collagen glycation and cross-linking in vitro. Extent of glycation, viscosity, collagen-linked fluorescence and pepsin solubility were assessed in different experimental procedures to investigate the effect of W. somnifera. Tail tendons obtained from rats (Rattus norvegicus) weighing 250-275 g were incubated with 50 mM glucose and 100 mg of metformin or Withania root powder or ethanolic extract of Withania under physiological conditions of temperature and pH for 30 days. Formation of advanced glycation end products (AGE) was measured by fluorescent method whereas the cross-linking of collagen was assessed by pepsin digestion and viscosity measurements. Tendon collagen incubated with glucose showed an increase in glycation, AGE and cross-linking of collagen. The collagen incubated with W. somnifera and metformin ameliorates these modifications. The ethanolic extract of Withania showed more prominent effect than Withania root powder. The activity of ethanolic extract of Withania is comparable to metformin, a known antiglycating agent. In conclusion, Withania could have therapeutic role in the prevention of glycation induced pathogenesis in diabetes mellitus and aging.

  17. A peptide study of the relationship between the collagen triple-helix and amyloid.

    PubMed

    Parmar, Avanish S; Nunes, Ana Monica; Baum, Jean; Brodsky, Barbara

    2012-10-01

    Type XXV collagen, or collagen-like amyloidogenic component, is a component of amyloid plaques, and recent studies suggest this collagen affects amyloid fibril elongation and has a genetic association with Alzheimer's disease. The relationship between the collagen triple helix and amyloid fibrils was investigated by studying peptide models, including a very stable triple helical peptide (Pro-Hyp-Gly)₁₀ , an amyloidogenic peptide GNNQQNY, and a hybrid peptide where the GNNQQNY sequence was incorporated between (GPO)(n) domains. Circular dichroism and nuclear magnetic resonance (NMR) spectroscopy showed the GNNQQNY peptide formed a random coil structure, whereas the hybrid peptide contained a central disordered GNNQQNY region transitioning to triple-helical ends. Light scattering confirmed the GNNQQNY peptide had a high propensity to form amyloid fibrils, whereas amyloidogenesis was delayed in the hybrid peptide. NMR data suggested the triple-helix constraints on the GNNQQNY sequence within the hybrid peptide may disfavor the conformational change necessary for aggregation. Independent addition of a triple-helical peptide to the GNNQQNY peptide under aggregating conditions delayed nucleation and amyloid fibril growth. The inhibition of amyloid nucleation depended on the Gly-Xaa-Yaa sequence and required the triple-helix conformation. The inhibitory effect of the collagen triple-helix on an amyloidogenic sequence, when in the same molecule or when added separately, suggests Type XXV collagen, and possibly other collagens, may play a role in regulating amyloid fibril formation.

  18. Collagen cross-linking: insights on the evolution of metazoan extracellular matrix

    PubMed Central

    Rodriguez-Pascual, Fernando; Slatter, David Anthony

    2016-01-01

    Collagens constitute a large family of extracellular matrix (ECM) proteins that play a fundamental role in supporting the structure of various tissues in multicellular animals. The mechanical strength of fibrillar collagens is highly dependent on the formation of covalent cross-links between individual fibrils, a process initiated by the enzymatic action of members of the lysyl oxidase (LOX) family. Fibrillar collagens are present in a wide variety of animals, therefore often being associated with metazoan evolution, where the emergence of an ancestral collagen chain has been proposed to lead to the formation of different clades. While LOX-generated collagen cross-linking metabolites have been detected in different metazoan families, there is limited information about when and how collagen acquired this particular modification. By analyzing telopeptide and helical sequences, we identified highly conserved, potential cross-linking sites throughout the metazoan tree of life. Based on this analysis, we propose that they have importantly contributed to the formation and further expansion of fibrillar collagens. PMID:27876853

  19. Collagen Fragmentation Promotes Oxidative Stress and Elevates Matrix Metalloproteinase-1 in Fibroblasts in Aged Human Skin

    PubMed Central

    Fisher, Gary J.; Quan, Taihao; Purohit, Trupta; Shao, Yuan; Cho, Moon Kyun; He, Tianyuan; Varani, James; Kang, Sewon; Voorhees, John J.

    2009-01-01

    Aged human skin is fragile because of fragmentation and loss of type I collagen fibrils, which confer strength and resiliency. We report here that dermal fibroblasts express increased levels of collagen-degrading matrix metalloproteinases-1 (MMP-1) in aged (>80 years old) compared with young (21 to 30 years old) human skin in vivo. Transcription factor AP-1 and α2β1 integrin, which are key regulators of MMP-1 expression, are also elevated in fibroblasts in aged human skin in vivo. MMP-1 treatment of young skin in organ culture causes fragmentation of collagen fibrils and reduces fibroblast stretch, consistent with reduced mechanical tension, as observed in aged human skin. Limited fragmentation of three-dimensional collagen lattices with exogenous MMP-1 also reduces fibroblast stretch and mechanical tension. Furthermore, fibroblasts cultured in fragmented collagen lattices express elevated levels of MMP-1, AP-1, and α2β1 integrin. Importantly, culture in fragmented collagen raises intracellular oxidant levels and treatment with antioxidant MitoQ10 significantly reduces MMP-1 expression. These data identify positive feedback regulation that couples age-dependent MMP-1-catalyzed collagen fragmentation and oxidative stress. We propose that this self perpetuating cycle promotes human skin aging. These data extend the current understanding of the oxidative theory of aging beyond a cellular-centric view to include extracellular matrix and the critical role that connective tissue microenvironment plays in the biology of aging. PMID:19116368

  20. Collagen fibrillogenesis in the development of the annulus fibrosus of the intervertebral disc.

    PubMed

    Hayes, Anthony J; Isaacs, Marc D; Hughes, C; Caterson, B; Ralphs, J R

    2011-10-11

    The annulus fibrosus of the intervertebral disc is a complex, radial-ply connective tissue consisting of concentric lamellae of oriented collagen. Whilst much is known of the structure of the mature annulus, less is known of how its complex collagenous architecture becomes established; an understanding of which could inform future repair/regenerative strategies. Here, using a rat disc developmental series, we describe events in the establishment of the collagenous framework of the annulus at light and electron microscopic levels and examine the involvement of class I and II small leucine rich proteoglycans (SLRPs) in the matrix assembly process. We show that a period of sustained, ordered matrix deposition follows the initial cellular differentiation/orientation phase within the foetal disc. Fibrillar matrix is deposited from recesses within the plasma membrane into compartments of interstitial space within the outer annulus - the orientation of the secreted collagen reflecting the initial cellular orientation of the laminae. Medially, we demonstrate the development of a reinforcing 'cage' of collagen fibre bundles around the foetal nucleus pulpous. This derives from the fusion of collagen bundles between presumptive end-plate and inner annulus. By birth, the distinct collagenous architectures are established and the disc undergoes considerable enlargement to maturity. We show that fibromodulin plays a prominent role in foetal development of the annulus and its attachment to vertebral bodies. With the exception of keratocan, the other SLRPs appear associated more with cartilage development within the vertebral column, but all become more prominent within the disc during its growth and differentiation.

  1. Outdoor Creative Play Areas.

    ERIC Educational Resources Information Center

    Miller, Peggy L.

    Guidelines are given for the development of outdoor play areas on school sites to provide children with natural areas and simple facilities for creative play. Site selection, analysis, and development are discussed. Natural, topographical features of the environment and natural play equipment are suggested. Illustrations are also presented to aid…

  2. The Excellence of Play.

    ERIC Educational Resources Information Center

    Moyles, Janet R., Ed.

    Recognizing that for young children, play is a tool for learning, this book compiles contributions by different authors, reflecting both up-to-date research and current classroom practice as they relate to children's play. Part 1 of the book explores the value of play as a cross-cultural concept as well as one rooted in the Western world. Gender…

  3. 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…

  4. Life! Through Play.

    ERIC Educational Resources Information Center

    Van Anne, Nancy

    This speech presents a review of research concerning the nature of play. Some of the formal characteristics of play are: (a) it is distinct from ordinary life in its "temporariness" and its limitless location; (b) there is an element of tension in play that leads to uncertainty concerning the outcome but at the same time provides the opportunity…

  5. 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…

  6. Nanomechanical mapping of hydrated rat tail tendon collagen I fibrils.

    PubMed

    Baldwin, Samuel J; Quigley, Andrew S; Clegg, Charlotte; Kreplak, Laurent

    2014-10-21

    Collagen fibrils play an important role in the human body, providing tensile strength to connective tissues. These fibrils are characterized by a banding pattern with a D-period of 67 nm. The proposed origin of the D-period is the internal staggering of tropocollagen molecules within the fibril, leading to gap and overlap regions and a corresponding periodic density fluctuation. Using an atomic force microscope high-resolution modulus maps of collagen fibril segments, up to 80 μm in length, were acquired at indentation speeds around 10(5) nm/s. The maps revealed a periodic modulation corresponding to the D-period as well as previously undocumented micrometer scale fluctuations. Further analysis revealed a 4/5, gap/overlap, ratio in the measured modulus providing further support for the quarter-staggered model of collagen fibril axial structure. The modulus values obtained at indentation speeds around 10(5) nm/s are significantly larger than those previously reported. Probing the effect of indentation speed over four decades reveals two distinct logarithmic regimes of the measured modulus and point to the existence of a characteristic molecular relaxation time around 0.1 ms. Furthermore, collagen fibrils exposed to temperatures between 50 and 62°C and cooled back to room temperature show a sharp decrease in modulus and a sharp increase in fibril diameter. This is also associated with a disappearance of the D-period and the appearance of twisted subfibrils with a pitch in the micrometer range. Based on all these data and a similar behavior observed for cross-linked polymer networks below the glass transition temperature, we propose that collagen I fibrils may be in a glassy state while hydrated.

  7. Early adsorption of collagen on the reduced rutile (110) surface mediated by water: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Zheng, Ting; Wu, Chunya; Chen, Mingjun

    2013-10-01

    The adsorption of collagen on the reduced rutile (110) surface with monatomic step defects in aqueous solution was modeled by classical molecular dynamics simulation. The step defects on the rutile surface were mainly parallel to the <11bar1> crystal orientation. Possible binding modes including direct and indirect binding modes, that were the peptide interacted with substrate surface directly or via the first layer water molecules, and the structural properties of collagen were discussed in order to analyze the adsorption dynamics of collagen on the reduced rutile surface. The simulation results suggested that the initial poses of collagen on the rutile surface could influence the adsorption conformation of collagen. The reduced rutile surface, which could increase the density of water molecules in the first layer, would provide active sites for collagen adsorption. The direct binding mode was responsible for the stable adsorption of collagen. The indirect binding mode may play an important part at the initial adsorption stage, but itself alone could not ‘trap’ the collagen on the surface stably unless the direct binding mode had already been formed. In addition, the triple helical structure of collagen was sustained by the inner-chain hydrogen bonds among different chains.

  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 association between seizures and deposition of collagen in the brain in porcine Taenia solium neurocysticercosis.

    PubMed

    Christensen, Nina M; Trevisan, Chiara; Leifsson, Páll S; Johansen, Maria V

    2016-09-15

    Neurocysticercosis caused by infection with Taenia solium is a significant cause of epilepsy and seizures in humans. The aim of this study was to assess the association between seizures and the deposition of collagen in brain tissue in pigs with T. solium neurocysticercosis. In total 78 brain tissue sections from seven pigs were examined histopathologically i.e. two pigs with epileptic seizures and T. solium cysts, four pigs without seizures but with cysts, and one non-infected control pig. Pigs with epileptic seizures had a larger amount of collagen in their brain tissue, showing as large fibrotic scars and moderate amount of collagen deposited around cysts, compared to pigs without seizures and the negative control pig. Our results indicate that collagen is likely to play a considerable part in the pathogenesis of seizures in T. solium neurocysticercosis.

  10. Collagen-derived matricryptins promote inhibitory nerve terminal formation in the developing neocortex

    PubMed Central

    Su, Jianmin; Chen, Jiang; Lippold, Kumiko; Monavarfeshani, Aboozar; Carrillo, Gabriela Lizana; Jenkins, Rachel

    2016-01-01

    Inhibitory synapses comprise only ∼20% of the total synapses in the mammalian brain but play essential roles in controlling neuronal activity. In fact, perturbing inhibitory synapses is associated with complex brain disorders, such as schizophrenia and epilepsy. Although many types of inhibitory synapses exist, these disorders have been strongly linked to defects in inhibitory synapses formed by Parvalbumin-expressing interneurons. Here, we discovered a novel role for an unconventional collagen—collagen XIX—in the formation of Parvalbumin+ inhibitory synapses. Loss of this collagen results not only in decreased inhibitory synapse number, but also in the acquisition of schizophrenia-related behaviors. Mechanistically, these studies reveal that a proteolytically released fragment of this collagen, termed a matricryptin, promotes the assembly of inhibitory nerve terminals through integrin receptors. Collectively, these studies not only identify roles for collagen-derived matricryptins in cortical circuit formation, but they also reveal a novel paracrine mechanism that regulates the assembly of these synapses. PMID:26975851

  11. 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.

  12. 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

  13. 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.

  14. Jellyfish collagen scaffolds for cartilage tissue engineering.

    PubMed

    Hoyer, Birgit; Bernhardt, Anne; Lode, Anja; Heinemann, Sascha; Sewing, Judith; Klinger, Matthias; Notbohm, Holger; Gelinsky, Michael

    2014-02-01

    Porous scaffolds were engineered from refibrillized collagen of the jellyfish Rhopilema esculentum for potential application in cartilage regeneration. The influence of collagen concentration, salinity and temperature on fibril formation was evaluated by turbidity measurements and quantification of fibrillized collagen. The formation of collagen fibrils with a typical banding pattern was confirmed by atomic force microscopy and transmission electron microscopy analysis. Porous scaffolds from jellyfish collagen, refibrillized under optimized conditions, were fabricated by freeze-drying and subsequent chemical cross-linking. Scaffolds possessed an open porosity of 98.2%. The samples were stable under cyclic compression and displayed an elastic behavior. Cytotoxicity tests with human mesenchymal stem cells (hMSCs) did not reveal any cytotoxic effects of the material. Chondrogenic markers SOX9, collagen II and aggrecan were upregulated in direct cultures of hMSCs upon chondrogenic stimulation. The formation of typical extracellular matrix components was further confirmed by quantification of sulfated glycosaminoglycans.

  15. Collagen-coated microparticles in drug delivery.

    PubMed

    Sehgal, Praveen Kumar; Srinivasan, Aishwarya

    2009-07-01

    Advantages of drug-incorporated collagen particles have been described for the controlled delivery system for therapeutic actions. The attractiveness of collagen lies in its low immunogenicity and high biocompatibility. It is also recognized by the body as a natural constituent rather than a foreign body. Our research and development efforts are focused towards addressing some of the limitations of collagen, like the high viscosity of an aqueous phase, nondissolution in neutral pH buffers, thermal instability (denaturation) and biodegradability, to make it an ideal material for drug delivery with particular reference to microparticles. These limitations could be overcome by making collagen conjugates with other biomaterials or chemically modifying collagen monomer without affecting its triple helical conformation and maintaining its native properties. This article highlights collagen microparticles' present status as a carrier in drug delivery.

  16. 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

  17. 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

  18. Stress controls the mechanics of collagen networks.

    PubMed

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

    2015-08-04

    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.

  19. Transglutaminase 2 and Factor XIII catalyze distinct substrates in differentiating osteoblastic cell line: utility of highly reactive substrate peptides.

    PubMed

    Watanabe, Kazuya; Tsunoda, Kanako; Itoh, Miho; Fukui, Mina; Mori, Hitoshi; Hitomi, Kiyotaka

    2013-01-01

    Differentiated osteoblastic cell line, MC3T3-E1 expresses transglutaminase 2 (TG2) and Factor XIII (FXIII). In previous studies, we identified isozyme-specific and highly reactive glutamine-donor substrate peptides (pepF11KA and pepT26) for each isozyme. Using these peptides, we compared the reaction products with lysine-donor substrates for each isozyme in differentiating MC3T3-E1 cells. By this analysis, distinct substrates for the activated TG2 and FXIII were detected in cultured cellular extract. Possible substrates that incorporated biotin-labeled peptides were further purified using streptavidin-affinity chromatography. Several isozyme-specific substrates were identified by mass spectrometry analysis of the purified fractions. These analyses also indicate the benefit of the substrate peptides for obtaining distinct substrates in a reaction mixture where two isozymes co-exist.

  20. 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

  1. Imaging Prostate Cancer Microenvironment by Collagen Hybridization

    DTIC Science & Technology

    2015-10-01

    INVESTIGATOR: Dr. Michael S. Yu CONTRACTING ORGANIZATION: University of Utah Salt Lake City, UT 84112 REPORT DATE: October 2015 TYPE OF REPORT: Annual...SUBTITLE Imaging Prostate Cancer Microenvironment by Collagen Hybridization 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0555 5c. PROGRAM ELEMENT...peptide (CMP) as a collagen targeting agents that will allow imaging of invasive PCa. Since CMP binds to unstructured collagens more readily, it is

  2. STUDIES ON THE FORMATION OF COLLAGEN

    PubMed Central

    Gross, Jerome

    1958-01-01

    Some properties of cold neutral salt extracts of fresh guinea pig dermis have been described in terms of viscosity, electrophoresis and sedimentation patterns, partial composition, the collagen content, conditions for extraction of collagen, and the effect of certain enzymes. Viscosity of the extracts depended on the collagen in solution as demonstrated by removal of this protein by precipitation or enzymatic degradation. The intrinsic viscosity of the crude 0.45 M extract, as well as that of the isolated collagen was 14.5, identical with that for collagen dissolved by dilute acid, indicating the same high asymmetry ratio for both. Electrophoresis of the skin extracts revealed a slow moving, high, sharp, poorly diffusing boundary in addition to a pattern superficially resembling that of serum. The ultracentrifuge pattern revealed a slowly sedimenting, hypersharp boundary following a large rapidly diffusing peak. The slow moving boundaries in both patterns were abolished by collagenase or heat precipitation of the collagen fraction. Hyaluronidase had no effect on either pattern. Neutral sulfate, chloride, and phosphate extracted more collagen than did thiocyanate. Very little collagen was extracted at 37°C. as compared with that removed at 3°C. A two stage fractionation procedure employing dilute trichloroacetic acid and ethanol is described for the isolation and purification of soluble collagen from crude extracts. PMID:13491760

  3. 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

  4. Development of a high-throughput screening system for the compounds that inhibit collagen-protein interactions.

    PubMed

    Okano-Kosugi, Hitomi; Matsushita, Osamu; Asada, Shinichi; Herr, Andrew B; Kitagawa, Kouki; Koide, Takaki

    2009-11-01

    Collagen-binding proteins (CBPs) play important roles in various physiological events. Some CBPs are regarded as targets for drug development; for example, platelet glycoprotein VI (GPVI) and heat shock protein 47 (HSP47) are promising targets for the development of novel antiplatelet and antifibrotic drugs, respectively. However, no systematic screening method to search compounds that inhibit collagen-CBP interactions have been developed, and only a few CBP inhibitors have been reported to date. In this study, a facile turbidimetric multiwell plate assay was developed to evaluate inhibitors of CBPs. The assay is based on the finding that CBPs retard spontaneous collagen fibril formation in vitro and that fibril formation is restored in the presence of compounds that interfere with the collagen-CBP interactions. Using the same platform, the assay was performed in various combinations of fibril-forming collagen types and CBPs. This homogeneous assay is simple, convenient, and suitable as an automated high-throughput screening system.

  5. 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.

  6. 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…

  7. 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…

  8. 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…

  9. An Invitation to Play.

    ERIC Educational Resources Information Center

    Lange, Jenny; Zieher, Connie

    The manual is intended to provide suggestions for play to parents of young children with exceptional educational needs. Nineteen types of activities are described and pictured, including make believe with boxes, dress-up activities, kitchen play, bubbles, small motor activities using beans and buttons, use of throw-away materials, painting,…

  10. 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,…

  11. Growing Up with Play

    ERIC Educational Resources Information Center

    Katch, Jane

    2008-01-01

    Many adults are afraid of boys' play today, believing that the aggression that is so common in boys' fantasies is dangerous and might make them become violent men. This personal reflection describes the importance of multiage play in showing little boys how to become big boys while encouraging empathy and emotional growth in older boys. The author…

  12. Theories of Play.

    ERIC Educational Resources Information Center

    Peller, Lili E.

    1996-01-01

    Discusses several theories of play advanced before the development of psychoanalysis, including the theories of surplus energy, recreation, and practice. Examines the psychoanalytical view advanced by Freud and others, which focuses on the emotional release of play and its role in discovery and learning. (MDM)

  13. 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…

  14. 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…

  15. Play, Toys and Television.

    ERIC Educational Resources Information Center

    Brougere, Gilles

    In Western societies, television has transformed the life, culture, and points of reference of the child. Its particular sphere of influence is the child's play culture. This play culture is not hermetic: it is very oriented toward manipulation; has a symbolic role as a representational medium; evolves along with the child; has a certain amount of…

  16. 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

  17. 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.

  18. [Collagen diseases with gastrointestinal manifestations].

    PubMed

    Takahashi, Hiroki; Ohara, Mikiko; Imai, Kohzoh

    2004-06-01

    Collagen vascular diseases are known to present with a diverse array of gastrointestinal manifestations. These can be classified as: 1) gastrointestinal damage due to the collagen vascular disease itself; 2) adverse events caused by pharmacotherapies; or 3) gastrointestinal infections following immunosuppression due to corticosteroid (CS) administration. The first group includes lupus enteritis and protein-losing gastroenteropathy in systemic lupus erythematosus (SLE), reflux esophagitis, chronic intestinal pseudo-obstruction, and pneumatosis cystoids intestinalis in systemic sclerosis, amyloidosis in rheumatoid arthritis, bowel ulcer and bleeding in rheumatoid vasculitis and microscopic polyangiitis, and ileocecal ulcer in Behcet disease. In particular, colonic ulcers associated with SLE represent refractory lesions resistant to CS. Analysis of reported cases showing colonic lesions with SLE (22 cases in Japan) revealed that mean duration of SLE was 9.9 years and 77% of colonic lesions were observed in the rectum and sigmoid colon. Half of the patients developed intestinal perforation or penetration, and 6 of the 11 patients with perforation died. The second group includes lesions in the small and large intestine due to nonsteroidal anti-inflammatory drugs (NSAIDs) and CSs, in addition to peptic ulcers. As perforation in CS-treated patients displays relatively high incidence with poor prognosis, careful attention to such complications is needed. The third group includes candidal esophagitis and cytomegalovirus (CMV) enteritis. Prompt diagnosis is required to prevent colonic bleeding and perforation due to CMV.

  19. 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.

  20. Thioamides in the collagen triple helix†

    PubMed Central

    Newberry, Robert W.; VanVeller, Brett

    2015-01-01

    To probe noncovalent interactions within the collagen triple helix, backbone amides were replaced with a thioamide isostere. This subtle substitution is the first in the collagen backbone that does not compromise thermostability. A triple helix with a thioamide as a hydrogen bond donor was found to be more stable than triple helices assembled from isomeric thiopeptides. PMID:25967743

  1. Oriented collagen nanocoatings for tissue engineering.

    PubMed

    Pastorino, Laura; Dellacasa, Elena; Scaglione, Silvia; Giulianelli, Massimo; Sbrana, Francesca; Vassalli, Massimo; Ruggiero, Carmelina

    2014-02-01

    Collagens are among the most widely present and important proteins composing the human total body, providing strength and structural stability to various tissues, from skin to bone. In this paper, we report an innovative approach to bioactivate planar surfaces with oriented collagen molecules to promote cells proliferation and alignment. The Langmuir-Blodgett technique was used to form a stable collagen film at the air-water interface and the Langmuir-Schaefer deposition was adopted to transfer it to the support surface. The deposition process was monitored by estimating the mass of the protein layers after each deposition step. Collagen films were then structurally characterized by atomic force, scanning electron and fluorescent microscopies. Finally, collagen films were functionally tested in vitro. To this aim, 3T3 cells were seeded onto the silicon supports either modified or not (control) by collagen film deposition. Cells adhesion and proliferation on collagen films were found to be greater than those on control both after 1 (p<0.05) and 7 days culture. Moreover, the functionalization of the substrate surface triggered a parallel orientation of cells when cultured on it. In conclusion, these data demonstrated that the Langmuir-Schaefer technique can be successfully used for the deposition of oriented collagen films for tissue engineering applications.

  2. Thioamides in the collagen triple helix.

    PubMed

    Newberry, Robert W; VanVeller, Brett; Raines, Ronald T

    2015-06-14

    To probe noncovalent interactions within the collagen triple helix, backbone amides were replaced with a thioamide isostere. This subtle substitution is the first in the collagen backbone that does not compromise thermostability. A triple helix with a thioamide as a hydrogen bond donor was found to be more stable than triple helices assembled from isomeric thiopeptides.

  3. Structure, physiology, and biochemistry of collagens.

    PubMed

    Mienaltowski, Michael J; Birk, David E

    2014-01-01

    Tendons and ligaments are connective tissues that guide motion, share loads, and transmit forces in a manner that is unique to each as well as the anatomical site and biomechanical stresses to which they are subjected. Collagens are the major molecular components of both tendons and ligaments. The hierarchical structure of tendon and its functional properties are determined by the collagens present, as well as their supramolecular organization. There are 28 different types of collagen that assemble into a variety of supramolecular structures. The assembly of specific supramolecular structures is dependent on the interaction with other matrix molecules as well as the cellular elements. Multiple suprastructural assemblies are integrated to form the functional tendon/ligament. This chapter begins with a discussion of collagen molecules. This is followed by a definition of the supramolecular structures assembled by different collagen types. The general principles involved in the assembly of collagen-containing suprastructures are presented focusing on the regulation of tendon collagen fibrillogenesis. Finally, site-specific differences are discussed. While generalizations can be made, differences exist between different tendons as well as between tendons and ligaments. Compositional differences will impact structure that in turn will determine functional differences. Elucidation of the unique physiology and pathophysiology of different tendons and ligaments will require an appreciation of the role compositional differences have on collagen suprastructural assembly, tissue organization, and function.

  4. Polarization effects in SHG of collagen

    NASA Astrophysics Data System (ADS)

    Xu, Paul; Cox, Guy C.; Ramshaw, John A. M.; Lukins, Philip B.; Sheppard, Colin J. R.

    2004-06-01

    The polarization dependence of the second harmonic emission of purified in-vitro reconstituted fibrils of collagen has been examined. The results confirmed the quasi-hexagonal crystalline structure within the fibrils. Interesting different polarization behaviours were seen between collagen types I and II, which can be utilized as an experimental technique for differentiation.

  5. Proton pump inhibitor induced collagen expression in colonocytes is associated with collagenous colitis

    PubMed Central

    Mori, Shiori; Kadochi, Yui; Luo, Yi; Fujiwara-Tani, Rina; Nishiguchi, Yukiko; Kishi, Shingo; Fujii, Kiyomu; Ohmori, Hitoshi; Kuniyasu, Hiroki

    2017-01-01

    AIM To elucidate the role of proton pump inhibitors (PPIs) in collagenous disease, direct effect of PPI on colonocytes was examined. METHODS Collagenous colitis is a common cause of non-bloody, watery diarrhea. Recently, there has been increasing focus on the use of proton PPIs as a risk factor for developing collagenous colitis. Mouse CT26 colonic cells were treated with PPI and/or PPI-induced alkaline media. Expression of fibrosis-associated genes was examined by RT-PCR. In human materials, collagen expression was examined by immunohistochemistry. RESULTS CT26 cells expressed a Na+-H+ exchanger gene (solute carrier family 9, member A2). Treatment with PPI and/or PPI-induced alkaline media caused growth inhibition and oxidative stress in CT26 cells. The treatment increased expression of fibrosis inducing factors, transforming growth factor β and fibroblast growth factor 2. The treatment also decreased expression of a negative regulator of collagen production, replication factor C1, resulting in increased expression of collagen types III and IV in association with lipid peroxide. In biopsy specimens from patients with collagenous colitis, type III and IV collagen were increased. Increase of type III collagen was more pronounced in PPI-associated collagenous colitis than in non-PPI-associated disease. CONCLUSION From these findings, the reaction of colonocytes to PPI might participate in pathogenesis of collagenous colitis. PMID:28321159

  6. Influence of collagen source on fibrillar architecture and properties of vitrified collagen membranes.

    PubMed

    Majumdar, Shoumyo; Guo, Qiongyu; Garza-Madrid, Marcos; Calderon-Colon, Xiomara; Duan, Derek; Carbajal, Priscilla; Schein, Oliver; Trexler, Morgana; Elisseeff, Jennifer

    2016-02-01

    Collagen vitrigel membranes are transparent biomaterials characterized by a densely organized, fibrillar nanostructure that show promise in the treatment of corneal injury and disease. In this study, the influence of different type I collagen sources and processing techniques, including acid-solubilized collagen from bovine dermis (Bov), pepsin-solubilized collagen from human fibroblast cell culture (HuCC), and ficin-solubilized collagen from recombinant human collagen expressed in tobacco leaves (rH), on the properties of the vitrigel membranes was evaluated. Postvitrification carbodiimide crosslinking (CX) was also carried out on the vitrigels from each collagen source, forming crosslinked counterparts BovXL, HuCCXL, and rHXL, respectively. Collagen membrane ultrastructure and biomaterial properties were found to rely heavily on both collagen source and crosslinking. Bov and HuCC samples showed a random fibrillar organization of collagen, whereas rH vitrigels showed remarkable regional fibril alignment. After CX, light transmission was enhanced in all groups. Denaturation temperatures after CX increased in all membranes, of which the highest increase was seen in rH (14.71°C), suggesting improved thermal stability of the collagen fibrils in the membranes. Noncrosslinked rH vitrigels may be reinforced through CX to reach levels of mechanical strength and thermal stability comparable to Bov.

  7. Collagen based barrier membranes for periodontal guided bone regeneration applications.

    PubMed

    Sheikh, Zeeshan; Qureshi, Javairia; Alshahrani, Abdullah M; Nassar, Heba; Ikeda, Yuichi; Glogauer, Michael; Ganss, Bernhard

    2017-01-01

    Certain cell populations within periodontal tissues possess the ability to induce regeneration, provided they have the opportunity to populate the wound or defect. Guided regeneration techniques have been investigated for regenerating periodontal tissues and such therapies usually utilize barrier membranes. Various natural and synthetic barrier membranes have been fabricated and tested to prevent epithelial and connective tissue cells from invading while allowing periodontal cells to selectively migrate into the defect. This paper focuses on the literature relevant to the use and potential of resorbable collagen membranes in GBR procedures, sites of periodontal and intrabony defects, in cases of socket and alveolar ridge preservation and at implant sites. The results of their use in GBR procedures has shown them to be effective and comparable with non-resorbable membranes with regards to clinical attachment gain, probing depth reduction and defect bone filling. They have also shown to prevent epithelial ingrowth into the defect space during the initial wound healing phase postsurgically. Collagen membranes have also been used for root coverage and GBR procedures and have shown good success rates comparable to subepithelial connective tissue grafts and expanded-polytetrafluoroethylene (e-PTFE) membranes. The future for periodontal tissue engineering is very exciting with the use of barrier membranes expected to continue playing a critical role. However, long-term clinical trials are required to further evaluate and confirm the efficacy of the available collagen barrier membranes for periodontal and bone regeneration use.

  8. 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

  9. Molecular level detection and localization of mechanical damage in collagen enabled by collagen hybridizing peptides

    NASA Astrophysics Data System (ADS)

    Zitnay, Jared L.; Li, Yang; Qin, Zhao; San, Boi Hoa; Depalle, Baptiste; Reese, Shawn P.; Buehler, Markus J.; Yu, S. Michael; Weiss, Jeffrey A.

    2017-03-01

    Mechanical injury to connective tissue causes changes in collagen structure and material behaviour, but the role and mechanisms of molecular damage have not been established. In the case of mechanical subfailure damage, no apparent macroscale damage can be detected, yet this damage initiates and potentiates in pathological processes. Here, we utilize collagen hybridizing peptide (CHP), which binds unfolded collagen by triple helix formation, to detect molecular level subfailure damage to collagen in mechanically stretched rat tail tendon fascicle. Our results directly reveal that collagen triple helix unfolding occurs during tensile loading of collagenous tissues and thus is an important damage mechanism. Steered molecular dynamics simulations suggest that a likely mechanism for triple helix unfolding is intermolecular shearing of collagen α-chains. Our results elucidate a probable molecular failure mechanism associated with subfailure injuries, and demonstrate the potential of CHP targeting for diagnosis, treatment and monitoring of tissue disease and injury.

  10. Molecular level detection and localization of mechanical damage in collagen enabled by collagen hybridizing peptides

    PubMed Central

    Zitnay, Jared L.; Li, Yang; Qin, Zhao; San, Boi Hoa; Depalle, Baptiste; Reese, Shawn P.; Buehler, Markus J.; Yu, S. Michael; Weiss, Jeffrey A.

    2017-01-01

    Mechanical injury to connective tissue causes changes in collagen structure and material behaviour, but the role and mechanisms of molecular damage have not been established. In the case of mechanical subfailure damage, no apparent macroscale damage can be detected, yet this damage initiates and potentiates in pathological processes. Here, we utilize collagen hybridizing peptide (CHP), which binds unfolded collagen by triple helix formation, to detect molecular level subfailure damage to collagen in mechanically stretched rat tail tendon fascicle. Our results directly reveal that collagen triple helix unfolding occurs during tensile loading of collagenous tissues and thus is an important damage mechanism. Steered molecular dynamics simulations suggest that a likely mechanism for triple helix unfolding is intermolecular shearing of collagen α-chains. Our results elucidate a probable molecular failure mechanism associated with subfailure injuries, and demonstrate the potential of CHP targeting for diagnosis, treatment and monitoring of tissue disease and injury. PMID:28327610

  11. Matrix metalloproteinase interactions with collagen and elastin

    PubMed Central

    Van Doren, Steven R.

    2015-01-01

    Most abundant in the extracellular matrix are collagens, joined by elastin that confers elastic recoil to the lung, aorta, and skin. These fibrils are highly resistant to proteolysis but can succumb to a minority of the matrix metalloproteinases (MMPs). Considerable inroads to understanding how such MMPs move to the susceptible sites in collagen and then unwind the triple helix of collagen monomers have been gained. The essential role in unwinding of the hemopexin-like domain of interstitial collagenases or the collagen binding domain of gelatinases is highlighted. Elastolysis is also facilitated by the collagen binding domain in the cases of MMP-2 and MMP-9, and remote exosites of the catalytic domain in the case of MMP-12. PMID:25599938

  12. 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.

  13. 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.

  14. Proline puckering parameters for collagen structure simulations

    NASA Astrophysics Data System (ADS)

    Wu, Di

    2015-03-01

    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.

  15. 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

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

    PubMed

    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

    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 β1 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 67kDa 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 peptide for the treatment of skin aging and wrinkles.

  17. NMR and Mutational Identification of the Collagen-Binding Site of the Chaperone Hsp47

    PubMed Central

    Yagi-Utsumi, Maho; Yoshikawa, Sumi; Yamaguchi, Yoshiki; Nishi, Yohei; Kurimoto, Eiji; Ishida, Yoshihito; Homma, Takayuki; Hoseki, Jun; Nishikawa, Yoshimi; Koide, Takaki; Nagata, Kazuhiro; Kato, Koichi

    2012-01-01

    Heat shock protein 47 (Hsp47) acts as a client-specific chaperone for collagen and plays a vital role in collagen maturation and the consequent embryonic development. In addition, this protein can be a potential target for the treatment of fibrosis. Despite its physiological and pathological importance, little is currently known about the collagen-binding mode of Hsp47 from a structural aspect. Here, we describe an NMR study that was conducted to identify the collagen-binding site of Hsp47. We used chicken Hsp47, which has higher solubility than its human counterpart, and applied a selective 15N-labeling method targeting its tryptophan and histidine residues. Spectral assignments were made based on site-directed mutagenesis of the individual residues. By inspecting the spectral changes that were observed upon interaction with a trimeric collagen peptide and the mutational data, we successfully mapped the collagen-binding site in the B/C β-barrel domain and a nearby loop in a 3D-homology model based upon a serpin fold. This conclusion was confirmed by mutational analysis. Our findings provide a molecular basis for the design of compounds that target the interaction between Hsp47 and procollagen as therapeutics for fibrotic diseases. PMID:23049894

  18. 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.

  19. A novel collagen gel-based measurement technique for quantitation of cell contraction force.

    PubMed

    Jin, Tianrong; Li, Li; Siow, Richard C M; Liu, Kuo-Kang

    2015-05-06

    Cell contraction force plays an important role in wound healing, inflammation,angiogenesis and metastasis. This study describes a novel method to quantify single cell contraction force in vitro using human aortic adventitial fibroblasts embedded in a collagen gel. The technique is based on a depth sensing nano-indentation tester to measure the thickness and elasticity of collagen gels containing stimulated fibroblasts and a microscopy imaging system to estimate the gel area. In parallel, a simple theoretical model has been developed to calculate cell contraction force based on the measured parameters. Histamine (100 mM) was used to stimulate fibroblast contraction while the myosin light chain kinase inhibitor ML-7 (25 mM) was used to inhibit cell contraction. The collagen matrix used in the model provides a physiological environment for fibroblast contraction studies. Measurement of changes in collagen gel elasticity and thickness arising from histamine treatments provides a novel convenient technique to measure cell contraction force within a collagen matrix. This study demonstrates that histamine can elicit a significant increase in contraction force of fibroblasts embedded in collagen,while the Young's modulus of the gel decreases due to the gel degradation.

  20. Collagen V expression is crucial in regional development of the supraspinatus tendon.

    PubMed

    Connizzo, Brianne K; Adams, Sheila M; Adams, Thomas H; Birk, David E; Soslowsky, Louis J

    2016-12-01

    Manipulations in cell culture and mouse models have demonstrated that reduction of collagen V results in altered fibril structure and matrix assembly. A tissue-dependent role for collagen V in determining mechanical function was recently established, but its role in determining regional properties has not been addressed. The objective of this study was to define the role(s) of collagen V expression in establishing the site-specific properties of the supraspinatus tendon. The insertion and midsubstance of tendons from wild type, heterozygous and tendon/ligament-specific null mice were assessed for crimp morphology, fibril morphology, cell morphology, as well as total collagen and pyridinoline cross-link (PYD) content. Fibril morphology was altered at the midsubstance of both groups with larger, but fewer, fibrils and no change in cell morphology or collagen compared to the wild type controls. In contrast, a significant disruption of fibril assembly was observed at the insertion site of the null group with the presence of structurally aberrant fibrils. Alterations were also present in cell density and PYD content. Altogether, these results demonstrate that collagen V plays a crucial role in determining region-specific differences in mouse supraspinatus tendon structure. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2154-2161, 2016.

  1. A novel collagen gel-based measurement technique for quantitation of cell contraction force

    PubMed Central

    Jin, Tianrong; Li, Li; Siow, Richard C. M.; Liu, Kuo-Kang

    2015-01-01

    Cell contraction force plays an important role in wound healing, inflammation, angiogenesis and metastasis. This study describes a novel method to quantify single cell contraction force in vitro using human aortic adventitial fibroblasts embedded in a collagen gel. The technique is based on a depth sensing nano-indentation tester to measure the thickness and elasticity of collagen gels containing stimulated fibroblasts and a microscopy imaging system to estimate the gel area. In parallel, a simple theoretical model has been developed to calculate cell contraction force based on the measured parameters. Histamine (100 µM) was used to stimulate fibroblast contraction while the myosin light chain kinase inhibitor ML-7 (25 µM) was used to inhibit cell contraction. The collagen matrix used in the model provides a physiological environment for fibroblast contraction studies. Measurement of changes in collagen gel elasticity and thickness arising from histamine treatments provides a novel convenient technique to measure cell contraction force within a collagen matrix. This study demonstrates that histamine can elicit a significant increase in contraction force of fibroblasts embedded in collagen, while the Young's modulus of the gel decreases due to the gel degradation. PMID:25977960

  2. The influence of structural design of PLGA/collagen hybrid scaffolds in cartilage tissue engineering.

    PubMed

    Dai, Wenda; Kawazoe, Naoki; Lin, Xiaoting; Dong, Jian; Chen, Guoping

    2010-03-01

    3D biodegradable porous scaffold plays a very important role in articular cartilage tissue engineering. We developed hybrid structures of 3D scaffolds that combined the advantages of natural type I collagen and synthetic PLGA knitted mesh. The mechanically strong PLGA mesh served as a skeleton while the collagen microsponges facilitated cell seeding and tissue formation. The scaffolds were divided into 3 groups: (1) THIN: collagen microsponge formed in interstices of PLGA mesh; (2) SEMI: collagen microsponge formed on one side of PLGA mesh; (3) SANDWICH: collagen sponge formed on both sides of PLGA mesh. Bovine chondrocytes were cultured in these scaffolds and transplanted subcutaneously into nude mice for 2, 4, and 8 weeks. All three groups of transplants showed homogeneous cell distribution, natural chondrocyte morphology, and abundant cartilaginous ECM deposition. Production of GAGs per DNA and the expression of type II collagen and aggrecan mRNA were much higher in the SEMI and SANDWICH groups than in the THIN group. When compared to native articular cartilage, the mechanical strength of the engineered cartilage reached 54.8%, 49.3% in Young's modulus and 68.8%, 62.7% in stiffness, respectively, in SEMI and SANDWICH. These scaffolds could be used for the tissue engineering of articular cartilage with adjustable thickness. The design of the hybrid structures provides a strategy for the preparation of 3D porous scaffolds.

  3. 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)

  4. Use of natural neural scaffolds consisting of engineered vascular endothelial growth factor immobilized on ordered collagen fibers filled in a collagen tube for peripheral nerve regeneration in rats.

    PubMed

    Ma, Fukai; Xiao, Zhifeng; Meng, Danqing; Hou, Xianglin; Zhu, Jianhong; Dai, Jianwu; Xu, Ruxiang

    2014-10-15

    The search for effective strategies for peripheral nerve regeneration has attracted much attention in recent years. In this study, ordered collagen fibers were used as intraluminal fibers after nerve injury in rats. Vascular endothelial growth factor (VEGF) plays an important role in nerve regeneration, but its very fast initial burst of activity within a short time has largely limited its clinical use. For the stable binding of VEGF to ordered collagen fibers, we fused a collagen-binding domain (CBD) to VEGF through recombinant DNA technology. Then, we filled the ordered collagen fibers-CBD-VEGF targeting delivery system in a collagen tube to construct natural neural scaffolds, which were then used to bridge transected nerve stumps in a rat sciatic nerve transection model. After transplantation, the natural neural scaffolds showed minimal foreign body reactions and good integration into the host tissue. Oriented collagen fibers in the collagen tube could guide regenerating axons in an oriented manner to the distal, degenerating nerve segment, maximizing the chance of target reinnervation. Functional and histological analyses indicated that the recovery of nerve function in the natural neural scaffolds-treated group was superior to the other grafted groups. The guiding of oriented axonal regeneration and effective delivery systems surmounting the otherwise rapid and short-lived diffusion of growth factors in body fluids are two important strategies in promoting peripheral nerve regeneration. The natural neural scaffolds described take advantage of these two aspects and may produce synergistic effects. These properties qualified the artificial nerve conduits as a putative candidate system for the fabrication of peripheral nerve reconstruction devices.

  5. Guide to collagen characterization for biomaterial studies.

    PubMed

    Abraham, Leah C; Zuena, Erin; Perez-Ramirez, Bernardo; Kaplan, David L

    2008-10-01

    The structure and remodeling of collagen in vivo is critical to the pathology and healing of many human diseases, as well as to normal tissue development and regeneration. In addition, collagen matrices in the form of fibers, coatings, and films are used extensively in biomaterial and biomedical applications. The specific properties of these matrices, both in terms of physical and chemical characteristics, have a direct impact on cellular adhesion, spreading, and proliferation rates, and ultimately on the rate and extent of new extracellular matrix formation in vitro or in vivo. In recent studies, it has also been shown that collagen matrix structure has a major impact on cell and tissue outcomes related to cellular aging and differentiation potential. Collagen structure is complex because of both diversity of source materials, chemistry, and structural hierarchy. With such significant impact of collagen features on biological outcomes, it becomes essential to consider an appropriate set of analytical tools, or guide, so that collagens attained from commercial vendors are characterized in a comparative manner as an integral part of studies focused on biological parameters. The analysis should include as a starting point: (a) structural detail-mainly focused on molecular mass, purity, helical content, and bulk thermal properties, (b) chemical features-mainly focused on surface elemental analysis and hydrophobicity, and (c) morphological features at different length scales. The application of these analytical techniques to the characterization of collagen biomaterial matrices is critical in order to appropriately correlate biological responses from different studies with experimental outcomes in vitro or in vivo. As a case study, the analytical tools employed for collagen biomaterial studies are reviewed in the context of collagen remodeling by fibroblasts. The goal is to highlight the necessity of understanding collagen biophysical and chemical features as a

  6. Mechanisms and Dynamics of Collagen Assembly

    NASA Astrophysics Data System (ADS)

    Tao, Jinhui; Friddle, Raymond; Wang, Debin; de Yoreo, Jim

    2013-03-01

    Collagen is the major structural protein of bone, dentine and it template the nucleation of biomineral phases. Both collagen conformation and architecture on substrate are critical for its function. We studied the mechanism of collagen I assembly on mica by in-situ AFM. At acidic condition, assembled architecture evolved from random fibers to co-aligned fibers and finally to bundles as the K+ concentration increased from 100 to 300mM. XPS and NEXAFS showed the concentration of K+ within the collagen layer increased and the intensity of absorption peak due to π*(C =O) resonance decreased with higher K+concentration. The magnitude of collagen-mica (C-M) and collagen-collagen (C-C) interactions were measured by dynamic force spectroscopy. The free energy ΔGb for C-M and C-C at 200mM K+were 13.7kT and 1.4kT, while ΔGb at 300mM K+ were 5.7kT and 12.3kT, respectively. The switch from co-aligned fibers to 3D bundles is driven by the reversal in the magnitude of C-C and C-M interactions. Our results indicate K+ complex with C =O of collagen and its effect on the strength of collagen-collagen bridging is the likely source of architecture control. Authors would like to acknowledge grant no. DK61673 from the National Institutes of Health. Theoretical analysis was supported by Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy under Contract no. DE-AC02-05CH1123.

  7. Liver collagen synthesis in murine schistosomiasis.

    PubMed Central

    Dunn, M A; Rojkind, M; Warren, K S; Hait, P K; Rifas, L; Seifter, S

    1977-01-01

    Collagen synthesis was measured in liver slices obtained from mice with hepatosplenic schistosomiasis. Enlarged fibrotic livers from these mice contained 20 times more collagen than normal. This model of hepatic fibrosis results from an inflammatory granulomatous host response to Schistosoma mansoni ova in portal tracts, rather than from direct lover cell injury as with carbon tetrachloride-induced liver fibrosis. Collagen synthesis, as measured by the formation of labeled protein-bound hydroxyproline, occurred in granulomas isolated from fibrotic livers. Labeled collagen that cochromatographed with type I collagen was extracted with neutral salt solution from liver slices incubated with labeled proline. The free proline pool of the liver was doubled in infected mice; coordinately, liver slices from these animals showed maximal collagen production when the concentration of free proline in the medium was raised to 0.4 mM, the same level measured in the fibrotic livers. Under such conditions, collagen synthesis was at a rate equivalent to the formation of 5.4 nmol of protein-bound hydroxyproline per g liver in 6 h. In comparative incubations in medium containing 0.2 mM proline, fibrotic liver slices produced 16-fold more collagen than normal slices. The proline analogue, L-azetidine 2-carboxylic acid, effectively inhibited synthesis of labeled collagen by fibrotic liver slices. These studies show the synthesis of collagen in a reproducible animal model of the most prevalent form of human liver fibrosis. Difinitition of the controlling factors in this system is of interest for the general problem of fibrosis produced by immunological responses. Images PMID:845255

  8. The effect of uniaxial tension on the stability of collagen fibers under the conditions of nonuniform laser heating

    NASA Astrophysics Data System (ADS)

    Zakharkina, O. L.; Ignat'eva, N. Yu.; Iksanov, R. R.; Kamenskii, V. A.; Sobol', E. N.; Lunin, V. V.

    2009-02-01

    Collagen degradation caused by IR laser irradiation in ligament tissues was studied by thermal analysis and cross-polarization optical coherent tomography. It was found that, at 60°C, laser-induced modification of the quasi-crystalline packing of ordered collagen fibers occurred without the helix-coil molecular conformation transition. It was shown that, for uniaxial tension of ligaments, laser irradiation caused serious distortions in the structure of collagen and increased the fraction of macromolecules in the random coil state. It was assumed that the thermomechanical effect of laser treatment during laser heating played an important role.

  9. 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.

  10. 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

  11. Highly aligned stromal collagen is a negative prognostic factor following pancreatic ductal adenocarcinoma resection

    PubMed Central

    Drifka, Cole R.; Loeffler, Agnes G.; Mathewson, Kara; Keikhosravi, Adib; Eickhoff, Jens C.; Liu, Yuming; Weber, Sharon M.

    2016-01-01

    Risk factors for pancreatic ductal adenocarcinoma (PDAC) progression after surgery are unclear, and additional prognostic factors are needed to inform treatment regimens and therapeutic targets. PDAC is characterized by advanced sclerosis of the extracellular matrix, and interactions between cancer cells, fibrillar collagen, and other stromal components play an integral role in progression. Changes in stromal collagen alignment have been shown to modulate cancer cell behavior and have important clinical value in other cancer types, but little is known about its role in PDAC and prognostic value. We hypothesized that the alignment of collagen is associated with PDAC patient survival. To address this, pathology-confirmed tissues from 114 PDAC patients that underwent curative-intent surgery were retrospectively imaged with Second Harmonic Generation (SHG) microscopy, quantified with fiber segmentation algorithms, and correlated to patient survival. The same tissue regions were analyzed for epithelial-to-mesenchymal (EMT), α-SMA, and syndecan-1 using complimentary immunohistostaining and visualization techniques. Significant inter-tumoral variation in collagen alignment was found, and notably high collagen alignment was observed in 12% of the patient cohort. Stratification of patients according to collagen alignment revealed that high alignment is an independent negative factor following PDAC resection (p = 0.0153, multivariate). We also found that epithelial expression of EMT and the stromal expression of α-SMA and syndecan-1 were positively correlated with collagen alignment. In summary, stromal collagen alignment may provide additional, clinically-relevant information about PDAC tumors and underscores the importance of stroma-cancer interactions. PMID:27776346

  12. Changes induced by ozone and ultraviolet light in type I collagen. Bovine Achilles tendon collagen versus rat tail tendon collagen.

    PubMed

    Fujimori, E

    1985-10-15

    High-molecular-mass aggregates were made soluble from insoluble collagens of bovine Achilles tendon and rat tail tendon by limited thermal hydrolysis. These polymeric collagen aggregates were cross-linked by 390-nm-fluorescent 3-hydroxy-pyridinium residues (excited at 325 nm) in the former tendon and by unknown non-fluorescent residues in the latter. With the solubilized insoluble-collagens from both tendons, as well as with acid-soluble collagen from rat tail tendon, other 350-385-nm fluorescence intensities (excited at 300 nm) were found to be higher in monomeric chains than in dimeric and polymeric chains. Low levels of ozone inhibited fibril formation of acid-soluble collagen particularly from young rat tail tendon, reacting with tyrosine residues and the 350-385-nm fluorophores. Aldehyde groups, involved in cross-linking, were not effectively modified by ozone. beta-Components (alpha-chain dimers) were not efficiently dissociated even by higher doses of ozone compared to gamma-components (alpha-chain trimers). Polymeric chain aggregates from bovine Achilles tendon collagen, whose 3-hydroxy-pyridinium cross-links are cleaved by ozone, were more readily dissociated by ozone than those from rat tail tendon collagen. Ultraviolet (300-nm) light, which destroyed the 350-385-nm fluorophores, inhibited fibril formation less effectively than ultraviolet (275-nm) light, which is absorbed by tyrosine residues, and did not dissociate collagen polymers from rat tail tendon. On the other hand, ultraviolet (320-nm) light, absorbed by 3-hydroxy-pyridinium cross-links which were rapidly photolyzed, partially dissociated polymeric collagen aggregates from bovine Achilles tendon after subsequent heating.

  13. Discoidin domain receptor 2 inhibits fibrillogenesis of collagen type 1.

    PubMed

    Mihai, Cosmin; Iscru, Daniel F; Druhan, Lawrence J; Elton, Terry S; Agarwal, Gunjan

    2006-09-01

    Discoidin domain receptors (DDR1 and DDR2) are widely expressed cell-surface receptors, which bind to and are activated by collagens, including collagen type 1. Activation of DDRs and the resulting downstream signaling is known to regulate the extracellular matrix. However, little is known about how DDRs interact with collagen and its direct impact on collagen regulation. Here, we have established that by binding to collagen, the extracellular domain (ECD) of DDR2 inhibits collagen fibrillogenesis and alters the morphology of collagen type 1 fibers. Our in vitro assays utilized DDR2-Fc fusion proteins, which contain only the ECD of DDR2. Using surface plasmon resonance, we confirmed that further oligomerization of DDR2-Fc (by means of anti-Fc antibody) greatly enhances its binding to immobilized collagen type 1. Collagen turbidity measurements and biochemical assays indicated that DDR2 delays the formation of collagen fibrils. Atomic force microscopy of soluble collagen revealed that a predominately monomeric state of collagen was present with DDR2, while control solutions had an abundance of polymeric collagen. Transmission electron microscopy of collagen fibers, showed that the native periodic banded structure of collagen fibers was weakened and nearly absent in the presence of DDR2. Further, using a cell-based assay we demonstrate that overexpression of full length DDR2 inhibits fibrillogenesis of collagen type 1. Our results demonstrate a novel and important functional role of the DDR2 ECD that may contribute to collagen regulation via modulation of fibrillogenesis.

  14. 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.

  15. Molecular structure of the collagen triple helix.

    PubMed

    Brodsky, Barbara; Persikov, Anton V

    2005-01-01

    The molecular conformation of the collagen triple helix confers strict amino acid sequence constraints, requiring a (Gly-X-Y)(n) repeating pattern and a high content of imino acids. The increasing family of collagens and proteins with collagenous domains shows the collagen triple helix to be a basic motif adaptable to a range of proteins and functions. Its rodlike domain has the potential for various modes of self-association and the capacity to bind receptors, other proteins, GAGs, and nucleic acids. High-resolution crystal structures obtained for collagen model peptides confirm the supercoiled triple helix conformation, and provide new information on hydrogen bonding patterns, hydration, sidechain interactions, and ligand binding. For several peptides, the helix twist was found to be sequence dependent, and such variation in helix twist may serve as recognition features or to orient the triple helix for binding. Mutations in the collagen triple-helix domain lead to a variety of human disorders. The most common mutations are single-base substitutions that lead to the replacement of one Gly residue, breaking the Gly-X-Y repeating pattern. A single Gly substitution destabilizes the triple helix through a local disruption in hydrogen bonding and produces a discontinuity in the register of the helix. Molecular information about the collagen triple helix and the effect of mutations will lead to a better understanding of function and pathology.

  16. Propranolol-induced elevation of pulmonary collagen

    SciTech Connect

    Lindenschmidt, R.C.; Witschi, H.P.

    1985-01-01

    Current concepts of collagen metabolism suggest that fibroblasts tightly control collagen production. One of the possible mechanisms of control is via the cyclic nucleotides, cyclic AMP (cAMP) and cyclic GMP (cGMP). Beta adrenergic agonists, by elevating intracellular cAMP levels, have been shown in vitro to suppress fibroblast collagen production; whereas beta adrenergic antagonists were effective in removing this suppression by blocking the rise in cAMP. In the present study with mice, the authors showed that administration of the beta adrenergic antagonists, propranolol, at a dose demonstrated to decrease the ratio of cAMP to cGMP, resulted in an elevation in total lung collagen in vivo. The increase in collagen was evident only when propranolol was administered before and during acute lung damage induced by either butylated hydroxytoluene, bleomycin or high concentrations of oxygen. There was no increase in lung collagen when propranolol administration was delayed after injury or when given to an undamaged lung. The authors propose that via beta adrenergic blockage by propranolol, fibroblasts involved in the normal reparative process may have lost a mechanism for regulatory control, resulting in excessive deposition of collagen. 38 references, 3 figures, 2 tables.

  17. 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

  18. Reduced difference of α₂-plasmin inhibitor levels between plasma and serum in patients with severe factor XIII deficiency, including autoimmune hemorrhaphilia due to anti-factor XIII antibodies.

    PubMed

    Ichinose, Akitada; Souri, Masayoshi

    2012-01-01

    Coagulation factor XIII/13 (FXIII/13) stabilizes fibrin molecules by creating crosslinks with other fibrin molecules as well as with α₂-plasmin inhibitor (α₂-PI). "Hemorrhagic acquired FXIII/13 deficiency" was formerly considered rare, but has been increasing recently in Japan. During the 10 months of our nationwide campaign, we diagnosed five new patients with "acquired hemorrhaphilia due to anti-FXIII/13 autoantibodies," after examining 20 newly suspected cases of "hemorrhagic acquired FXIII/13 deficiency." When FXIII/13 activity was reduced to less than 50% of normal, it was proportional to the difference in α₂-PI levels between plasma and serum (plasma-serum α₂-PI), likely due to its cross-linking to fibrin by activated FXIII/13. Accordingly, decreased amounts of the plasma-serum α₂-PI ex vivo may reflect reduced FXIII/13 activity in vivo. The plasma-serum α₂-PI may thus also be a useful diagnostic marker for severe FXIII/13 deficiency.

  19. Metal-triggered collagen peptide disk formation.

    PubMed

    Przybyla, David E; Chmielewski, Jean

    2010-06-16

    A collagen peptide was designed for metal-triggered, hierarchical assembly through a radial growth mechanism. To achieve radial assembly, H-(byp)(2) containing Pro-Hyp-Gly repeating sequences and two staggered bipyridine ligands within the peptide was synthesized. Triple helix formation resulted in the placement of six bipyridine ligands along the triple helix, and the addition of metal ions resulted in the formation of nanometer-sized collagen peptide disks. These structures were found to disassemble upon the addition of EDTA, demonstrating that radial assembly of collagen peptide triple helices could be realized with the addition of metal ions.

  20. Looking into Children's Play Communities

    ERIC Educational Resources Information Center

    Mabry, Mark; Fucigna, Carolee

    2009-01-01

    Play, particularly children's sociodramatic play, is the cornerstone of early childhood classrooms in the United States. Early childhood educators learn and expound mantras of "the value of play," "play-based programs," "children learning through play," and "play as child's work." They strive to promote the importance of making a place for play in…

  1. Creative Outdoor Play Areas.

    ERIC Educational Resources Information Center

    Miller, Peggy L.

    Considering the creation of proper play areas for children (school sites, municipal and mini parks, private homes and backyards, shopping centers, apartment complexes, recreational areas, roadside parks, nursery schools, churches, summer camps, and drive-in theaters) as one of today's major challenges, the author recommends that professional…

  2. 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…

  3. Playing with Science

    ERIC Educational Resources Information Center

    Vieyra, Rebecca; Edwards, Teon; Rowe, Elizabeth; Asbell-Clarke, Jodi

    2015-01-01

    Gaming is becoming an effective form of learning and assessment and shouldn't be overlooked in an increasingly technological world. The games described in this article ("Impulse," "Quantum Spectre," and "Ravenous"), entertaining enough to be played by the general public, are also appropriate and useful in a classroom…

  4. "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…

  5. 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…

  6. 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…

  7. 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…

  8. Collagen scaffolds loaded with collagen-binding NGF-beta accelerate ulcer healing.

    PubMed

    Sun, Wenjie; Lin, Hang; Chen, Bing; Zhao, Wenxue; Zhao, Yannan; Xiao, Zhifeng; Dai, Jianwu

    2010-03-01

    Studies have shown that exogenous nerve growth factor (NGF) accelerates ulcer healing, but the inefficient growth factor delivery system limits its clinical application. In this report, we found that the native human NGF-beta fused with a collagen-binding domain (CBD) could form a collagen-based NGF targeting delivery system, and the CBD-fused NGF-beta could bind to collagen membranes efficiently. Using the rabbit dermal ischemic ulcer model, we have found that this targeting delivery system maintains a higher concentration and stronger bioactivity of NGF-beta on the collagen membranes by promoting peripheral nerve growth. Furthermore, it enhances the rate of ulcer healing through accelerating the re-epithelialization of dermal ulcer wounds and the formation of capillary lumens within the newly formed tissue area. Thus, collagen membranes loaded with collagen-targeting human NGF-beta accelerate ulcer healing efficiently.

  9. Epidermal cells adhere preferentially to type IV (basement membrane) collagen

    PubMed Central

    1979-01-01

    Epidermal cells from adult guinea pig skin attach and differentiate preferentially on substrates of type IV (basement membrane) collagen, compared to those of types I--III collagen. In contrast, guinea pig dermal fibroblasts attach equally well to all four collagen substrates. Fibronectin mediates the attachment of fibroblasts but not of epidermal cells to collagen. PMID:422650

  10. The 2001 June 21 Eclipse Polarimetric Observations of the Fe XIII 1074.7 nm Emission Line

    NASA Astrophysics Data System (ADS)

    Habbal, S. R.; Arndt, M. B.; Nayfeh, M. H.; Arnaud, J.; Johnson, J.; Hegwer, S.; Ene, A.

    2003-05-01

    Polarimetric measurements of the coronal forbidden lines have been recognized for quite some time as a diagnostic tool for inferring the direction of the coronal magnetic field. Following the first successful measurements by Eddy et al. (1973) during the total solar eclipse of 1966, an observing campaign using the coronagraph at Sacramento Peak Observatory was pursued between 1977-1980 (Arnaud and Newkirk, 1987). All these measurements yielded the surprising result that the direction of polarization implied a predominantly radial coronal magnetic field. We report on the polarization measurements of the Fe XIII 1074.7nm line, the strongest of the coronal forbidden lines, which were obtained during the total solar eclipse of 2001 June 21 from Zambia. In addition to confirming the earlier results of a predominantly radial field, the signature of nano-size interplanetary dust in the inner corona, most likely in the form of silicon nanoparticles, appeared for the first time in these measurements. The signature of these particles also coincides with the radial expansion of coronal holes outwards from the Sun, a signature that has never appeared in any measurement before. Support for this work was provided by NSF grant ATM-0003661 and NASA grant NAG5-10873

  11. 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.

  12. Factor XIII-A transglutaminase deficient mice show signs of metabolically healthy obesity on high fat diet

    PubMed Central

    Myneni, Vamsee D.; Mousa, Aisha; Kaartinen, Mari T.

    2016-01-01

    F13A1 gene, which encodes for Factor XIII-A blood clotting factor and a transglutaminase enzyme, was recently identified as a potential causative gene for obesity in humans. In our previous in vitro work, we showed that FXIII-A regulates preadipocyte differentiation and modulates insulin signaling via promoting plasma fibronectin assembly into the extracellular matrix. To understand the role of FXIII-A in whole body energy metabolism, here we have characterized the metabolic phenotype of F13a1−/− mice. F13a1−/− and F13a1+/+ type mice were fed chow or obesogenic, high fat diet for 20 weeks. Weight gain, total fat mass and fat pad mass, glucose handling, insulin sensitivity, energy expenditure and, morphological and biochemical analysis of adipose tissue was performed. We show that mice lacking FXIII-A gain weight on obesogenic diet, similarly as wild type mice, but exhibit a number of features of metabolically healthy obesity such as protection from developing diet-induced insulin resistance and hyperinsulinemia. Mice also show normal fasting glucose levels, larger adipocytes, decreased extracellular matrix accumulation and inflammation of adipose tissue, as well as decreased circulating triglycerides. This study reveals that FXIII-A transglutaminase can regulate whole body insulin sensitivity and may have a role in the development of diet-induced metabolic disturbances. PMID:27759118

  13. Nanoscale scraping and dissection of collagen fibrils.

    PubMed

    Wenger, M P E; Horton, M A; Mesquida, P

    2008-09-24

    The main function of collagen is mechanical, hence there is a fundamental scientific interest in experimentally investigating the mechanical and structural properties of collagen fibrils on the nanometre scale. Here, we present a novel atomic force microscopy (AFM) based scraping technique that can dissect the outer layer of a biological specimen. Applied to individual collagen fibrils, the technique was successfully used to expose the fibril core and reveal the presence of a D-banding-like structure. AFM nanoindentation measurements of fibril shell and core indicated no significant differences in mechanical properties such as stiffness (reduced modulus), hardness, adhesion and adhesion work. This suggests that collagen fibrils are mechanically homogeneous structures. The scraping technique can be applied to other biological specimens, as demonstrated on the example of bacteria.

  14. In vitro Sirius Red collagen assay measures the pattern shift from soluble to deposited collagen.

    PubMed

    Chen, Chun; Yang, Shanmin; Zhang, Mei; Zhang, Zhenhuan; Zhang, Bingrong; Han, Deping; Ma, Jun; Wang, Xiaohui; Hong, Jingshen; Guo, Yansong; Okunieff, Paul; Zhang, Lurong

    2013-01-01

    In this study, we compared two in vitro collagen production assays ([(3)H]-proline incorporation and Sirius Red) for their ability to determine the pattern shift from soluble to deposited collagen. The effect of the antifibrotic agent, triptolide (TPL), on collagen production was also studied. The results showed that: (1) 48 h after NIH 3T3 (murine embryo fibroblast) and HFL-1(human fetal lung fibroblast) were exposed to transforming growth factor-beta 1 (TGF-β), there was an increase in soluble collagen in the culture medium; (2) on day 4, soluble collagen declined, whereas deposited collagen increased; (3) Sirius Red was easier to use than [(3)H]-proline incorporation and more consistently reflected the collagen pattern shift from soluble to deposited; (4) the in vitro Sirius Red assay took less time than the in vivo assay to determine the effect of TPL. Our results suggest that: (a) the newly synthesized soluble collagen can sensitively evaluate an agent's capacity for collagen production and (b) Sirius Red is more useful than [(3)H]-proline because it is easier to use, more convenient, less time consuming, and does not require radioactive material.

  15. 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.

  16. Thermal stability of collagen triple helix.

    PubMed

    Xu, Yujia

    2009-01-01

    Chief among the challenges of characterizing the thermal stability of the collagen triple helix are the lack of the reversibility of the thermal transition and the presence of multiple folding-unfolding steps during the thermal transition which rarely follows the simple two-state, all-or-none mechanism. Despite of the difficulties inherited in the quantitative depiction of the thermal transition of collagen, biophysical studies combined with proteolysis and mutagenesis approaches using full-chain collagens, short synthetic peptides, and recombinant collagen fragments have revealed molecular features of the thermal unfolding of the subdomains of collagen and led to a better understanding of the diverse biological functions of this versatile protein. The subdomain of collagen generally refers to a segment of the long, rope-like triple helical molecule that can unfold cooperatively as an independent unit whose properties (their size, location, and thermal stability) are considered essential for the molecular recognition during the self-assembly of collagen and during the interactions of collagen with other macromolecules. While the unfolding of segments of the triple helix at temperatures below the apparent melting temperature of the molecule has been used to interpret much of the features of the thermal unfolding of full-chain collagens, the thermal studies of short, synthetic peptides have firmly established the molecular basis of the subdomains by clearly demonstrating the close dependence of the thermal stability of a triple helix on the constituent amino acid residues at the X and the Y positions of the characteristic Gly-X-Y repeating sequence patterns of the triple helix. Studies using recombinant collagen fragments further revealed that in the context of the long, linear molecule, the stability of a segment of the triple helix is also modulated by long-range impact of the local interactions such as the interchain salt bridges. Together, the combined approaches

  17. Playing tricks to ions

    NASA Astrophysics Data System (ADS)

    Leibfried, Dietrich

    2017-01-01

    Ted Hänsch's career is defined by breaking new ground in experimental physics. Curiosity, vivid imagination, deep understanding, patience and tenacity are part of the winning formula, but perhaps an equally important ingredient may be Ted's favorite past-time of exploring new tricks in his "Spiellabor" (play-lab), that often resurfaced as key ingredients in rather serious experiments later. On the occasion of Ted's 75th birthday, a few past and potential future experiments with trapped ions are playfully surveyed here. Some of these tricks are already part of the trade, some are currently emerging and a few are mostly speculation today. Maybe some of the latter will be realized and even prove useful in the future.

  18. 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.

  19. Unusual fragmentation pathways in collagen glycopeptides

    PubMed Central

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

    2013-01-01

    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. PMID:23633013

  20. 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.

  1. Viewpoints: The High School Play.

    ERIC Educational Resources Information Center

    Harbison, Lawrence; And Others

    1981-01-01

    Presents opinions of professionals on the current state of the high school play. Participants include a playwright, play supplier, high school theater instructor, workshop leader, and play publisher. Discusses selection, production, and performance of plays. (JMF)

  2. 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

  3. Eupatilin ameliorates collagen induced arthritis.

    PubMed

    Kim, Juryun; Kim, Youngkyun; Yi, Hyoju; Jung, Hyerin; Rim, Yeri Alice; Park, Narae; Jung, Seung Min; Park, Sung-Hwan; Ju, Ji Hyeon

    2015-03-01

    Eupatilin is the main active component of DA-9601, an extract from Artemisia. Recently, eupatilin was reported to have anti-inflammatory properties. We investigated the anti-arthritic effect of eupatilin in a murine arthritis model and human rheumatoid synoviocytes. DA-9601 was injected into collagen-induced arthritis (CIA) mice. Arthritis score was regularly evaluated. Mouse monocytes were differentiated into osteoclasts when eupatilin was added simultaneously. Osteoclasts were stained with tartrate-resistant acid phosphatase and then manually counted. Rheumatoid synoviocytes were stimulated with TNF-α and then treated with eupatilin, and the levels of IL-6 and IL-1β mRNA expression in synoviocytes were measured by RT-PCR. Intraperitoneal injection of DA-9601 reduced arthritis scores in CIA mice. TNF-α treatment of synoviocytes increased the expression of IL-6 and IL-1β mRNAs, which was inhibited by eupatilin. Eupatilin decreased the number of osteoclasts in a concentration dependent manner. These findings, showing that eupatilin and DA-9601 inhibited the expression of inflammatory cytokines and the differentiation of osteoclasts, suggest that eupatilin and DA-9601 is a candidate anti-inflammatory agent.

  4. Spherical silver nanoparticles in the detection of thermally denatured collagens.

    PubMed

    Ahumada, Manuel; McLaughlin, Sarah; Pacioni, Natalia L; Alarcon, Emilio I

    2016-03-01

    We have developed a rapid colorimetric method to determine the concentration of denatured collagen in solution, which is based on the collagen-silver nanoparticle corona formation. Using the proposed method, the lowest detectable concentration of denatured collagen protein in a solution of pure collagen was 14.7, 8.5, and 8.6 μg mL(-1) for porcine (PCOL), rat tail (RCOL), and type I human recombinant (HCOL) collagen, respectively.

  5. The peculiar collagens of mussel byssus.

    PubMed

    Waite, J H; Qin, X X; Coyne, K J

    1998-06-01

    The byssal collagens of marine mussels are extracorporeal collagens that function in byssal threads under tension. Each byssal thread resembles a shock absorber in its mechanical design: it is strong and stiff at one end and pliably elastic at the other. Primary structures of three of these collagens (preCols), deduced from cDNAs, reveal signal peptide sequences, but no N-glycosylation sites or propeptides typical of procollagens. The collagen domain (40-50 kDa) represents roughly half the mass of the mature molecules and is distinguished by its central location, abundant Gly-Gly-X repeats, and "flaws" (usually Gly deletions). Flanking the collagen domains on both sides are structural domains that resemble elastin in preCol-P, spider drag-line silk in preCol-D, and Gly-rich cell wall proteins in preCol-NG. Not surprisingly, studies of preCol distribution in byssal threads suggest preCol-P enhancement in the elastic proximal portion, while preCol-D predominates in the stiffer distal portion. PreCol-NG, in contrast, is evenly distributed. Although no data are yet available on the fibrillogenesis and cross-linking of the preCols, the quarter-stagger assembly of fibrillar interstitial collagens does not pertain since preCols lack the terminal peptides of tropocollagen. Metal-binding by histidines may mediate the initial inter- and intramolecular stabilization of preCols in the byssus.

  6. 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

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

    PubMed

    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.

  8. Modulation of tumor cell stiffness and migration by type IV collagen through direct activation of integrin signaling pathway.

    PubMed

    Chen, Sheng-Yi; Lin, Jo-Shi; Yang, Bei-Chang

    2014-08-01

    Excessive collagen deposition plays a critical role in tumor progression and metastasis. To understand how type IV collagen affects mechanical stiffness and migration, low-collagen-IV-expressing transfectants of B16F10, U118MG, and Huh7 (denoted shCol cells) were established by the lentiviral-mediated delivery of small interfering RNA against type IV-α1 collagen (Col4A1). Although having similar growth rates, shCol cells showed a flatter morphology compared to that of the corresponding controls. Notably, knocking down the Col4A1 gene conferred the cells with higher levels of elasticity and lower motility. Exposure to blocking antibodies against human β1 integrin or α2β1 integrin or the pharmacological inhibition of Src and ERK activity by PP1 and U0126, respectively, effectively reduced cell motility and raised cell stiffness. Reduced Src and ERK activities in shCol cells indicate the involvement of a collagen IV/integrin signaling pathway. The forced expression of β1 integrin significantly stimulated Src and ERK phosphorylation, reduced cell stiffness, and accelerated cell motility. In an experimental metastasis assay using C57BL/6 mice, B16F10 shCol cells formed significantly fewer and smaller lung nodules, confirming the contribution of collagen to metastasis. In summary, the integrin signaling pathway activated in a tumor environment with collagen deposition is responsible for low cell elasticity and high metastatic ability.

  9. Modulation of heat shock protein 90 affects TGF-β-induced collagen synthesis in human dermal fibroblast cells.

    PubMed

    Lee, Sae Bin; Lim, A-Ram; Rah, Dong Kyun; Kim, Kyung Soo; Min, Hyun Jin

    2016-12-01

    Heat shock protein 90 is a chaperone molecule that aids in proper folding of target proteins. Recently, heat shock protein 90 was found to play a role in would healing through regulation of fibroblast functions. The aim of the present study was to investigate the role of heat shock protein 90 in collagen synthesis in human dermal fibroblasts. The effects of transforming growth factor-β, 17-N-allylamino-17-demethoxygeldanamycin, and transfection of heat shock protein 90 were evaluated by real-time PCR, western blot, and immunofluorescence assays. The Smad 2/3 and Akt pathways were evaluated to identify the signaling pathways involved in collagen synthesis. Heat shock protein 90 and collagen levels were compared in keloid and control tissues by immunohistochemical analysis. The expression of collagen was significantly increased after treatment with transforming growth factor-β, while 17-N-allylamino-17-demethoxygeldanamycin inhibited transforming growth factor-β-induced collagen synthesis. Overexpression of heat shock protein 90 itself with or without transforming growth factor-β increased collagen synthesis. These effects were dependent on Smad 2/3 pathway signaling. Finally, expression of heat shock protein 90 was increased in keloid tissue compared with control tissues. Taken together, these results demonstrate that modulation of heat shock protein 90 influences transforming growth factor-β-induced collagen synthesis via regulation of Smad 2/3 phosphorylation.

  10. 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

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

    PubMed

    Liu, Panpan; Yan, Shuangquan; Chen, Mayun; Chen, Ali; Yao, Dan; Xu, Xiaomei; Cai, Xueding; Wang, Liangxing; Huang, Xiaoying

    2015-04-01

    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

  12. Effect of green tea extract on advanced glycation and cross-linking of tail tendon collagen in streptozotocin induced diabetic rats.

    PubMed

    Babu, Pon Velayutham Anandh; Sabitha, Kuruvimalai Ekambaram; Shyamaladevi, Chennam Srinivasulu

    2008-01-01

    Diabetes leads to modification of collagen such as advanced glycation and cross-linking which play an important role in the pathogenesis of diabetes mellitus. We have investigated the effect of green tea on modification of collagen in streptozotocin (60 mg/kg body weight) induced diabetic rats. To investigate the therapeutic effect of green tea, treatment was begun six weeks after the onset of diabetes and green tea extract (300 mg/kg body weight) was given orally for 4 weeks. The collagen content, extent of advanced glycation, advanced glycation end products (AGE) and cross-linking of tail tendon collagen were investigated. Green tea reduced the tail tendon collagen content which increased in diabetic rats. Accelerated advanced glycation and AGE in diabetic animals, as detected by Ehrlich's-positive material and collagen linked fluorescence respectively were reduced significantly by green tea. The solubility of tail tendon collagen decreased significantly in diabetic rats indicating a remarkable increase in the cross-linking, whereas green tea increases the solubility of collagen in diabetic rats. The present study reveals that green tea is effective in reducing the modification of tail tendon collagen in diabetic rats. Thus green tea may have a therapeutic effect in the treatment of glycation induced complications of diabetes.

  13. Glycation Contributes to Interaction Between Human Bone Alkaline Phosphatase and Collagen Type I.

    PubMed

    Halling Linder, Cecilia; Enander, Karin; Magnusson, Per

    2016-03-01

    Bone is a biological composite material comprised primarily of collagen type I and mineral crystals of calcium and phosphate in the form of hydroxyapatite (HA), which together provide its mechanical properties. Bone alkaline phosphatase (ALP), produced by osteoblasts, plays a pivotal role in the mineralization process. Affinity contacts between collagen, mainly type II, and the crown domain of various ALP isozymes were reported in a few in vitro studies in the 1980s and 1990s, but have not attracted much attention since, although such interactions may have important implications for the bone mineralization process. The objective of this study was to investigate the binding properties of human collagen type I to human bone ALP, including the two bone ALP isoforms B1 and B2. ALP from human liver, human placenta and E. coli were also studied. A surface plasmon resonance-based analysis, supported by electrophoresis and blotting, showed that bone ALP binds stronger to collagen type I in comparison with ALPs expressed in non-mineralizing tissues. Further, the B2 isoform binds significantly stronger to collagen type I in comparison with the B1 isoform. Human bone and liver ALP (with identical amino acid composition) displayed pronounced differences in binding, revealing that post-translational glycosylation properties govern these interactions to a large extent. In conclusion, this study presents the first evidence that glycosylation differences in human ALPs are of crucial importance for protein-protein interactions with collagen type I, although the presence of the ALP crown domain may also be necessary. Different binding affinities among the bone ALP isoforms may influence the mineral-collagen interface, mineralization kinetics, and degree of bone matrix mineralization, which are important factors determining the material properties of bone.

  14. Collagen fibre arrangement and functional crimping pattern of the medial collateral ligament in the rat knee.

    PubMed

    Franchi, Marco; Quaranta, Marilisa; Macciocca, Maria; Leonardi, Luisa; Ottani, Vittoria; Bianchini, Paolo; Diaspro, Alberto; Ruggeri, Alessandro

    2010-12-01

    Ligaments have been described as multifascicular structures with collagen fibres cross-connecting to each other or running straight and parallel also showing a waviness or crimping pattern playing as a shock absorber/recoiling system during joint motions. A particular collagen array and crimping pattern in different ligaments may reflect different biomechanical roles and properties. The aim of the study was to relate the 3D collagen arrangement in the crimping pattern of the medial collateral ligament (MCL) to its functional role. The MCL is one of the most injured ligaments during sports activities and an experimental model to understand the rate, quality and composition of ligaments healing. A deep knowledge of structure-function relationship of collagen fibres array will improve the development of rehabilitation protocols and more appropriate exercises for recovery of functional activity. The rat MCL was analysed by polarized light microscopy, confocal laser microscopy and scanning electron microscopy (SEM). Histomorphometric analysis demonstrated that MCL crimps have a smaller base length versus other tendons. SEM observations demonstrated that collagen fibres showing few crimps were composed of fibrils intertwining and crossing one another in the outer region. Confocal laser analyses excluded a helical array of collagen fibres. By contrast, in the core portion, densely packed straight collagen fibres ran parallel to the main axis of the ligament being interrupted both by planar crimps, similar to tendon crimps, and by newly described right-handed twisted crimps. It is concluded that planar crimps could oppose or respond exclusively to tensional forces parallel to the main ligament axis, whereas the right-handed twisted crimps could better resist/respond to a complex of tensional/rotational forces within the ligament thus opposing to an external rotation of tibia.

  15. Triple-helical peptides: an approach to collagen conformation, stability, and self-association.

    PubMed

    Brodsky, Barbara; Thiagarajan, Geetha; Madhan, Balaraman; Kar, Karunakar

    2008-05-01

    Peptides have been an integral part of the collagen triple-helix structure story, and have continued to serve as useful models for biophysical studies and for establishing biologically important sequence-structure-function relationships. High resolution structures of triple-helical peptides have confirmed the basic Ramachandran triple-helix model and provided new insights into the hydration, hydrogen bonding, and sequence dependent helical parameters in collagen. The dependence of collagen triple-helix stability on the residues in its (Gly-X-Y)(n) repeating sequence has been investigated by measuring melting temperatures of host-guest peptides and an on-line collagen stability calculator is now available. Although the presence of Gly as every third residue is essential for an undistorted structure, interruptions in the repeating (Gly-X-Y)(n) amino acid sequence pattern are found in the triple-helical domains of all nonfibrillar collagens, and are likely to play a role in collagen binding and degradation. Peptide models indicate that small interruptions can be incorporated into a rod-like triple-helix with a highly localized effect, which perturbs hydrogen bonds and places the standard triple-helices on both ends out of register. In contrast to natural interruptions, missense mutations which replace one Gly in a triple-helix domain by a larger residue have pathological consequences, and studies on peptides containing such Gly substitutions clarify their effect on conformation, stability, and folding. Recent studies suggest peptides may also be useful in defining the basic principles of collagen self-association to the supramolecular structures found in tissues.

  16. Collagen and elastin cross-linking is altered during aberrant late lung development associated with hyperoxia.

    PubMed

    Mižíková, Ivana; Ruiz-Camp, Jordi; Steenbock, Heiko; Madurga, Alicia; Vadász, István; Herold, Susanne; Mayer, Konstantin; Seeger, Werner; Brinckmann, Jürgen; Morty, Rory E

    2015-06-01

    Maturation of the lung extracellular matrix (ECM) plays an important role in the formation of alveolar gas exchange units. A key step in ECM maturation is cross-linking of collagen and elastin, which imparts stability and functionality to the ECM. During aberrant late lung development in bronchopulmonary dysplasia (BPD) patients and animal models of BPD, alveolarization is blocked, and the function of ECM cross-linking enzymes is deregulated, suggesting that perturbed ECM cross-linking may impact alveolarization. In a hyperoxia (85% O2)-based mouse model of BPD, blunted alveolarization was accompanied by alterations to lung collagen and elastin levels and cross-linking. Total collagen levels were increased (by 63%). The abundance of dihydroxylysinonorleucine collagen cross-links and the dihydroxylysinonorleucine-to-hydroxylysinonorleucine ratio were increased by 11 and 18%, respectively, suggestive of a profibrotic state. In contrast, insoluble elastin levels and the abundance of the elastin cross-links desmosine and isodesmosine in insoluble elastin were decreased by 35, 30, and 21%, respectively. The lung collagen-to-elastin ratio was threefold increased. Treatment of hyperoxia-exposed newborn mice with the lysyl oxidase inhibitor β-aminopropionitrile partially restored normal collagen levels, normalized the dihydroxylysinonorleucine-to-hydroxylysinonorleucine ratio, partially normalized desmosine and isodesmosine cross-links in insoluble elastin, and partially restored elastin foci structure in the developing septa. However, β-aminopropionitrile administration concomitant with hyperoxia exposure did not improve alveolarization, evident from unchanged alveolar surface area and alveoli number, and worsened septal thickening (increased by 12%). These data demonstrate that collagen and elastin cross-linking are perturbed during the arrested alveolarization of developing mouse lungs exposed to hyperoxia.

  17. Collagen scaffold microenvironments modulate cell lineage commitment for differentiation of bone marrow cells into regulatory dendritic cells

    PubMed Central

    Fang, Yongxiang; Wang, Bin; Zhao, Yannan; Xiao, Zhifeng; Li, Jing; Cui, Yi; Han, Sufang; Wei, Jianshu; Chen, Bing; Han, Jin; Meng, Qingyuan; Hou, Xianglin; Luo, Jianxun; Dai, Jianwu; Jing, Zhizhong

    2017-01-01

    The microenvironment plays a pivotal role for cell survival and functional regulation, and directs the cell fate determination. The biological functions of DCs have been extensively investigated to date. However, the influences of the microenvironment on the differentiation of bone marrow cells (BMCs) into dendritic cells (DCs) are not well defined. Here, we established a 3D collagen scaffold microenvironment to investigate whether such 3D collagen scaffolds could provide a favourable niche for BMCs to differentiate into specialised DCs. We found that BMCs embedded in the 3D collagen scaffold differentiated into a distinct subset of DC, exhibiting high expression of CD11b and low expression of CD11c, co-stimulator (CD40, CD80, CD83, and CD86) and MHC-II molecules compared to those grown in 2D culture. DCs cultured in the 3D collagen scaffold possessed weak antigen uptake ability and inhibited T-cell proliferation in vitro; in addition, they exhibited potent immunoregulatory function to alleviate allo-delay type hypersensitivity when transferred in vivo. Thus, DCs differentiated in the 3D collagen scaffold were defined as regulatory DCs, indicating that collagen scaffold microenvironments probably play an important role in modulating the lineage commitment of DCs and therefore might be applied as a promising tool for generation of specialised DCs. PMID:28169322

  18. Exosite Interactions Impact Matrix Metalloproteinase Collagen Specificities*

    PubMed Central

    Robichaud, Trista K.; Steffensen, Bjorn; Fields, Gregg B.

    2011-01-01

    Members of the matrix metalloproteinase (MMP) family selectively cleave collagens in vivo. However, the substrate structural determinants that facilitate interaction with specific MMPs are not well defined. We hypothesized that type I–III collagen sequences located N- or C-terminal to the physiological cleavage site mediate substrate selectivity among MMP-1, MMP-2, MMP-8, MMP-13, and MMP-14/membrane-type 1 (MT1)-MMP. The enzyme kinetics for hydrolysis of three fluorogenic triple-helical peptides (fTHPs) was evaluated herein. The first fTHP contained consensus residues 769–783 from type I–III collagens, the second inserted α1(II) collagen residues 763–768 N-terminal to the consensus sequence, and the third inserted α1(II) collagen residues 784–792 C-terminal to the consensus sequence. Our analyses showed that insertion of the C-terminal residues significantly increased kcat/Km and kcat for MMP-1. MMP-13 showed the opposite behavior with a decreased kcat/Km and kcat and a greatly improved Km in response to the C-terminal residues. Insertion of the N-terminal residues enhanced kcat/Km and kcat for MMP-8 and MT1-MMP. For MMP-2, the C-terminal residues enhanced Km and dramatically decreased kcat, resulting in a decrease in the overall activity. These changes in activities and kinetic parameters represented the collagen preferences of MMP-8, MMP-13, and MT1-MMP well. Thus, interactions with secondary binding sites (exosites) helped direct the specificity of these enzymes. However, MMP-1 collagen preferences were not recapitulated by the fTHP studies. The preference of MMP-1 for type III collagen appears to be primarily based on the flexibility of the hydrolysis site of type III collagen compared with types I and II. Further characterization of exosite determinants that govern interactions of MMPs with collagenous substrates should aid the development of pharmacotherapeutics that target individual MMPs. PMID:21896477

  19. Collagen Fiber Orientation and Dispersion in the Upper Cervix of Non-Pregnant and Pregnant Women

    PubMed Central

    Myers, Kristin M.; Vink, Joy Y.; Wapner, Ronald J.; Hendon, Christine P.

    2016-01-01

    The structural integrity of the cervix in pregnancy is necessary for carrying a pregnancy until term, and the organization of human cervical tissue collagen likely plays an important role in the tissue’s structural function. Collagen fibers in the cervical extracellular matrix exhibit preferential directionality, and this collagen network ultrastructure is hypothesized to reorient and remodel during cervical softening and dilation at time of parturition. Within the cervix, the upper half is substantially loaded during pregnancy and is where the premature funneling starts to happen. To characterize the cervical collagen ultrastructure for the upper half of the human cervix, we imaged whole axial tissue slices from non-pregnant and pregnant women undergoing hysterectomy or cesarean hysterectomy respectively using optical coherence tomography (OCT) and implemented a pixel-wise fiber orientation tracking method to measure the distribution of fiber orientation. The collagen fiber orientation maps show that there are two radial zones and the preferential fiber direction is circumferential in a dominant outer radial zone. The OCT data also reveal that there are two anatomic regions with distinct fiber orientation and dispersion properties. These regions are labeled: Region 1—the posterior and anterior quadrants in the outer radial zone and Region 2—the left and right quadrants in the outer radial zone and all quadrants in the inner radial zone. When comparing samples from nulliparous vs multiparous women, no differences in these fiber properties were noted. Pregnant tissue samples exhibit an overall higher fiber dispersion and more heterogeneous fiber properties within the sample than non-pregnant tissue. Collectively, these OCT data suggest that collagen fiber dispersion and directionality may play a role in cervical remodeling during pregnancy, where distinct remodeling properties exist according to anatomical quadrant. PMID:27898677

  20. Lipocytes from normal rat liver release a neutral metalloproteinase that degrades basement membrane (type IV) collagen.

    PubMed Central

    Arthur, M J; Friedman, S L; Roll, F J; Bissell, D M

    1989-01-01

    We report a proteinase that degrades basement-membrane (type IV) collagen and is produced by the liver. Its cellular source is lipocytes (fat-storing or Ito cells). Lipocytes were isolated from normal rat liver and established in primary culture. The cells synthesize and secrete a neutral proteinase, which by gelatin-substrate gel electrophoresis and gel filtration chromatography, has a molecular mass of 65,000 D. The enzyme is secreted in latent form and is activated by p-aminophenylmercuric acetate but not by trypsin. Enzyme activity in the presence of EDTA is restored selectively by zinc and is unaffected by serine-protease inhibitors. In assays with radiolabeled soluble substrates, it degrades native type IV (basement membrane) collagen but not interstitial collagen types I or V and exhibits no activity against laminin or casein. At temperatures causing partial denaturation of soluble collagen in vitro, it rapidly degrades types I and V. Thus, it is both a type IV collagenase and gelatinase. The enzyme may play a role in initiating breakdown of the subendothelial matrix in the Disse space as well as augmenting the effects of collagenases that attack native interstitial collagen. Images PMID:2551922

  1. Contributions of cation-π interactions to the collagen triple helix stability.

    PubMed

    Chen, Chia-Ching; Hsu, Wei; Hwang, Kuo-Chu; Hwu, Jih Ru; Lin, Chun-Cheng; Horng, Jia-Cherng

    2011-04-01

    Cation-π interactions are found to be an important noncovalent force in proteins. Collagen is a right-handed triple helix composed of three left-handed PPII helices, in which (X-Y-Gly) repeats dominate in the sequence. Molecular modeling indicates that cation-π interactions could be formed between the X and Y positions in adjacent collagen strands. Here, we used a host-guest peptide system: (Pro-Hyp-Gly)(3)-(Pro-Y-Gly-X-Hyp-Gly)-(Pro-Hyp-Gly)(3), where X is an aromatic residue and Y is a cationic residue, to study the cation-π interaction in the collagen triple helix. Circular dichroism (CD) measurements and Tm data analysis show that the cation-π interactions involving Arg have a larger contribution to the conformational stability than do those involving Lys, and Trp forms a weaker cation-π interaction with cationic residues than expected as a result of steric effects. The results also show that the formation of cation-π interactions between Arg and Phe depends on their relative positions in the strand. Moreover, the fluorinated and methylated Phe substitutions show that an electron-withdrawing or electron-donating substituent on the aromatic ring can modulate its π-electron density and the cation-π interaction in collagen. Our data demonstrate that the cation-π interaction could play an important role in stabilizing the collagen triple helix.

  2. 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.

  3. Collagen Unfolding Accelerates Water Influx, Determining Hydration in the Interstitial Matrix

    PubMed Central

    McGee, Maria P.; Morykwas, Michael; Shelton, Julie; Argenta, Louis

    2012-01-01

    In the interstitial matrix, collagen unfolding at physiologic temperatures is thought to facilitate interactions with enzymes and scaffold molecules during inflammation, tissue remodeling, and wound healing. We tested the hypothesis that it also plays a role in modulating flows and matrix hydration potential. After progressively unfolding dermal collagen in situ, we measured the hydration parameters by osmotic stress techniques and modeled them as linear functions of unfolded collagen, quantified by differential scanning calorimetry after timed heat treatment. Consistent with the hypothetical model, the thermodynamic and flow parameters obtained experimentally were related linearly to the unfolded collagen fraction. The increases in relative humidity and intensity of T2 maps were also consistent with interfacial energy contributions to the hydration potential and the hydrophobic character of the newly formed protein/water interfaces. As a plausible explanation, we propose that increased tension at interfaces formed during collagen unfolding generate local gradients in the matrix that accelerate water transfer in the dermis. This mechanism adds a convective component to interstitial transfer of biological fluids that, unlike diffusion, can speed the dispersion of water and large solutes within the matrix. PMID:23200049

  4. 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

  5. Molecular Characterization of Collagen Hydroxylysine O-Glycosylation by Mass Spectrometry: Current Status

    PubMed Central

    Perdivara, Irina; Yamauchi, Mitsuo; Tomer, Kenneth B.

    2014-01-01

    The most abundant proteins in vertebrates – the collagen family proteins – play structural and biological roles in the body. The predominant member, type I collagen, provides tissues and organs with structure and connectivity. This protein has several unique post-translational modifications that take place intra- and extra-cellularly. With growing evidence of the relevance of such post-translational modifications in health and disease, the biological significance of O-linked collagen glycosylation has recently drawn increased attention. However, several aspects of this unique modification – the requirement for prior lysyl hydroxylation as a substrate, involvement of at least two distinct glycosyl transferases, its involvement in intermolecular crosslinking – have made its molecular mapping and quantitative characterization challenging. Such characterization is obviously crucial for understanding its biological significance. Recent progress in mass spectrometry has provided an unprecedented opportunity for this type of analysis. This review summarizes recent advances in the area of O-glycosylation of fibrillar collagens and their characterization using state-of-the-art liquid chromatography–mass spectrometry-based methodologies, and perspectives on future research. The analytical characterization of collagen crosslinking and advanced glycation end-products are not addressed here. PMID:25414518

  6. Immunohistochemical expression of Type IV Collagen and Autocrine Motility Factor Receptor in Odontogenic Tumours

    PubMed Central

    Sethi, Sneha

    2014-01-01

    Background: Autocrine motility factor receptor (AMFR) is a tumour motility stimulating protein secreted by tumour cells. The protein encoded by this gene is a glycosylated transmembrane protein and a receptor for autocrine motility factor. It has been known to play a role in progression of neoplastic lesions. Basement membranes are specialized extracellular matrices that serve as structural barriers as well as substrates for cellular interactions. The network of type IV collagen is thought to define the scaffold integrating other components such as laminins and perlecan into highly organized supramolecular architecture. The aim of this study was to determine and evaluate the immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor in odontogenic lesions. Materials and Methods: Immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor was evaluated in 31 odontogenic lesions, including unicystic ameloblastoma, multicystic ameloblastoma, keratocystic odontogenic tumour and ameloblastic carcinoma. Normal follicular tissue formed the control. Results: Maximum expression for Type IV Collagen was seen in multicystic ameloblastoma and minimum expression in keratocystic odontogenic tumour. The maximum expression of AMFR was seen in ameloblastic carcinoma and minimum expression in multicystic ameloblastoma. Conclusion: The results of this study suggested an association of loss of expression of type IV Collagen with progression of lesion. AMFR expression was found to be associated with the aggressive potential of tumours. PMID:25478440

  7. 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.

  8. Biomechanics of the lung parenchyma: critical roles of collagen and mechanical forces.

    PubMed

    Suki, Béla; Ito, Satoru; Stamenovic, Dimitrije; Lutchen, Kenneth R; Ingenito, Edward P

    2005-05-01

    The biomechanical properties of connective tissues play fundamental roles in how mechanical interactions of the body with its environment produce physical forces at the cellular level. It is now recognized that mechanical interactions between cells and the extracellular matrix (ECM) have major regulatory effects on cellular physiology and cell-cycle kinetics that can lead to the reorganization and remodeling of the ECM. The connective tissues are composed of cells and the ECM, which includes water and a variety of biological macromolecules. The macromolecules that are most important in determining the mechanical properties of these tissues are collagen, elastin, and proteoglycans. Among these macromolecules, the most abundant and perhaps most critical for structural integrity is collagen. In this review, we examine how mechanical forces affect the physiological functioning of the lung parenchyma, with special emphasis on the role of collagen. First, we overview the composition of the connective tissue of the lung and their complex structural organization. We then describe how mechanical properties of the parenchyma arise from its composition as well as from the architectural organization of the connective tissue. We argue that, because collagen is the most important load-bearing component of the parenchymal connective tissue, it is also critical in determining the homeostasis and cellular responses to injury. Finally, we overview the interactions between the parenchymal collagen network and cellular remodeling and speculate how mechanotransduction might contribute to disease propagation and the development of small- and large-scale heterogeneities with implications to impaired lung function in emphysema.

  9. 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.

  10. Play in Practice: Case Studies in Young Children's Play.

    ERIC Educational Resources Information Center

    Brown, Cheryl Render, Ed.; Marchant, Catherine, Ed.

    This book uses a collection of stories, or "cases," as a basis for reflection, discussion, and learning about the many roles "play" has in children's lives. Each of the 12 cases addresses an issue of play from one of three categories--the role of adults in play, the cultural meanings of play, and the issues related to play in…

  11. Collagen-Binding Peptidoglycans Inhibit MMP Mediated Collagen Degradation and Reduce Dermal Scarring

    PubMed Central

    Snyder, Paul W.; Freeman, Lynetta; Panitch, Alyssa

    2011-01-01

    Scarring of the skin is a large unmet clinical problem that is of high patient concern and impact. Wound healing is complex and involves numerous pathways that are highly orchestrated, leaving the skin sealed, but with abnormal organization and composition of tissue components, namely collagen and proteoglycans, that are then remodeled over time. To improve healing and reduce or eliminate scarring, more rapid restoration of healthy tissue composition and organization offers a unique approach for development of new therapeutics. A synthetic collagen-binding peptidoglycan has been developed that inhibits matrix metalloproteinase-1 and 13 (MMP-1 and MMP-13) mediated collagen degradation. We investigated the synthetic peptidoglycan in a rat incisional model in which a single dose was delivered in a hyaluronic acid (HA) vehicle at the time of surgery prior to wound closure. The peptidoglycan treatment resulted in a significant reduction in scar tissue at 21 days as measured by histology and visual analysis. Improved collagen architecture of the treated wounds was demonstrated by increased tensile strength and transmission electron microscopy (TEM) analysis of collagen fibril diameters compared to untreated and HA controls. The peptidoglycan's mechanism of action includes masking existing collagen and inhibiting MMP-mediated collagen degradation while modulating collagen organization. The peptidoglycan can be synthesized at low cost with unique design control, and together with demonstrated preclinical efficacy in reducing scarring, warrants further investigation for dermal wound healing. PMID:21779387

  12. Effect of kiwifruit juice on beef collagen.

    PubMed

    Sugiyama, Sumi; Hirota, Aya; Okada, Chikako; Yorita, Taeko; Sato, Kenji; Ohtsuki, Kozo

    2005-02-01

    The objective of this study is to clarify the difference in susceptibility to protease digestion by kiwifruit juice between collagen domains under different conditions. In addition, the effect of pre-treatment with kiwifruit juice on collagen in meat during cooking processes was examined. Kiwifruit juice can degrade denatured collagen, but it can not cleave the triple helical domain of collagen. Thus, kiwifruit juice does not have collagenase activity. On the other hand, the cross-linked subunits of acid-soluble collagen were converted to monomeric subunits by kiwifruit juice treatment at acidic pH, suggesting that the globular domains, in which cross-links preferentially occur, can be degraded by kiwifruit juice. The pre-treatment with kiwifruit juice significantly decreased the shear force of connective tissue in comparison with other pre-treatments without protease activity, but inversely increased the liberation of collagen-related peptides in the outer solution by heating processes at 50 and 70 degrees C or by a shorter heating time at 100 degrees C. This can be explained by the protease-mediated degradation of globular domains. However, this effect was not observed with a prolonged heating period at 100 degrees C, and the liberation of collagen-related peptides by pre-treatment with kiwifruit juice at 100 degrees C was less than that at 70 degrees C for all heating periods. Thus, it can be suggested that the pre-treatment with kiwifruit juice might be useful in meat softening under vacuum-cooking and grilling, but not under stewing.

  13. 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.

  14. 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

  15. 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.

  16. Recombinant expression of hydroxylated human collagen in Escherichia coli.

    PubMed

    Rutschmann, Christoph; Baumann, Stephan; Cabalzar, Jürg; Luther, Kelvin B; Hennet, Thierry

    2014-05-01

    Collagen is the most abundant protein in the human body and thereby a structural protein of considerable biotechnological interest. The complex maturation process of collagen, including essential post-translational modifications such as prolyl and lysyl hydroxylation, has precluded large-scale production of recombinant collagen featuring the biophysical properties of endogenous collagen. The characterization of new prolyl and lysyl hydroxylase genes encoded by the giant virus mimivirus reveals a method for production of hydroxylated collagen. The coexpression of a human collagen type III construct together with mimivirus prolyl and lysyl hydroxylases in Escherichia coli yielded up to 90 mg of hydroxylated collagen per liter culture. The respective levels of prolyl and lysyl hydroxylation reaching 25 % and 26 % were similar to the hydroxylation levels of native human collagen type III. The distribution of hydroxyproline and hydroxylysine along recombinant collagen was also similar to that of native collagen as determined by mass spectrometric analysis of tryptic peptides. The triple helix signature of recombinant hydroxylated collagen was confirmed by circular dichroism, which also showed that hydroxylation increased the thermal stability of the recombinant collagen construct. Recombinant hydroxylated collagen produced in E. coli supported the growth of human umbilical endothelial cells, underlining the biocompatibility of the recombinant protein as extracellular matrix. The high yield of recombinant protein expression and the extensive level of prolyl and lysyl hydroxylation achieved indicate that recombinant hydroxylated collagen can be produced at large scale for biomaterials engineering in the context of biomedical applications.

  17. 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.

  18. Release of alpha 2-plasmin inhibitor from plasma fibrin clots by activated coagulation factor XIII. Its effect on fibrinolysis.

    PubMed Central

    Mimuro, J; Kimura, S; Aoki, N

    1986-01-01

    When blood coagulation takes place in the presence of calcium ions, alpha 2-plasmin inhibitor (alpha 2PI) is cross-linked to fibrin by activated coagulation Factor XIII (XIIIa) and thereby contributes to the resistance of fibrin to fibrinolysis. It was previously shown that the cross-linking reaction is a reversible one, since the alpha 2PI-fibrinogen cross-linked complex could be dissociated. In the present study we have shown that the alpha 2PI-fibrin cross-linking reaction is also a reversible reaction and alpha 2PI which had been cross-linked to fibrin can be released from fibrin by disrupting the equilibrium, resulting in a decrease of its resistance to fibrinolysis. When the fibrin clot formed from normal plasma in the presence of calcium ions was suspended in alpha 2PI-deficient plasma of buffered saline, alpha 2PI was gradually released from fibrin on incubation. When alpha 2PI was present in the suspending milieu, the release was decreased inversely to the concentrations of alpha 2PI in the suspending milieu. The release was accelerated by supplementing XIIIa or the presence of a high concentration of the NH2-terminal 12-residue peptide of alpha 2PI (N-peptide) which is cross-linked to fibrin in exchange for the release of alpha 2PI. When the release of alpha 2PI from fibrin was accelerated by XIIIa or N-peptide, the fibrin became less resistant to the fibrinolytic process, resulting in an acceleration of fibrinolysis which was proportional to the degree of the release of alpha 2PI. These results suggest the possibility that alpha 2PI could be released from fibrin in vivo by disrupting the equilibrium of the alpha 2PI-fibrin cross-linking reaction, and that the release would result in accelerated thrombolysis. Images PMID:2419360

  19. Collagen polymorphism in idiopathic chronic pulmonary fibrosis.

    PubMed Central

    Seyer, J M; Hutcheson, E T; Kang, A H

    1976-01-01

    Collagens in normal human lung and in idiopathic chronic fibrosis were investigated in terms of their covalent structure and compared for possible alterations in the diseased state. Collagens were solubilized by limited digestion with pepsin under nondenaturing conditions, and after purification they, were fractionated into types I and III. Carboxymethylcellulose and agarose chromatography of both types I and III collagens, and amino acid and carbohydrate analyses of the resulting alpha-chains indicated that the alpha 1 (I), alpha 2, and alpha 1 (III) chains of normal human lung were identical with the human skin alpha-chains in all respects examined except that the normal lung chains contained higher levels of hydroxylysine. Examination of collagens obtained from the diseased lung revealed that the content of hydroxylysine of the alpha 1 (I) and the alpha 1 (III) chains appeared to be diminished as compared to the normal lung chains. The values, expressed as residues per 1,000 residues, are 7.1 and 8.3 for the alpha 1 (I) and the alpha 1 (III) chains, respectively, as compared to 10.0 and 11.1 for the alpha-chains from the normal tissue. The chromatographic properties and amino acid and carbohydrate composition of the alpha-chains from the diseased tissue were otherwise indistinguishable from those of normal lung. In addition, isolation and characterization of the CNBr peptides of alpha 1 (I), alpha 2 and alpha 1 (III) from the diseased lung revealed no significant differences from the CNBr peptides from other human tissues reported previously. Normal and diseased lungs were also digested with CNBr, and the resultant alpha 1 (I) and alpha 1 (III) peptides were separated chromatographically. The relative quantities of these peptides indicate that type III collagen constitutes 33% of the total collagen in normal human lung, with the remainder being type I, whereas in idiopathic chronic pulmonary fibrosis, the relative content of type III collagen is markedly

  20. 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.

  1. Collagen degrading activity associated with Mycobacterium species

    PubMed Central

    Masso, F; Paez, A; Varela, E; d Diaz; Zenteno, E; Montano, L

    1999-01-01

    BACKGROUND—The mechanism of Mycobacterium tuberculosis penetration into tissues is poorly understood but it is reasonable to assume that there is a contribution from proteases capable of disrupting the extracellular matrix of the pulmonary epithelium and the blood vessels. A study was undertaken to identify and characterise collagen degrading activity of M tuberculosis.
METHODS—Culture filtrate protein extract (CFPE) was obtained from reference mycobacterial strains and mycobacteria isolated from patients with tuberculosis. The collagen degrading activity of CFPE was determined according to the method of Johnson-Wint using 3H-type I collagen. The enzyme was identified by the Birkedal-Hansen and Taylor method and its molecular mass determined by SDS-PAGE and Sephacryl S-300 gel filtration chromatography using an electroelution purified enzyme.
RESULTS—CFPE from Mycobacterium tuberculosis strain H37Rv showed collagenolytic activity that was four times higher than that of the avirulent strain H37Ra. The 75 kDa enzyme responsible was divalent cation dependent. Other mycobacterial species and those isolated from patients with tuberculosis also had collagen degrading activity.
CONCLUSIONS—Mycobacterium species possess a metalloprotease with collagen degrading activity. The highest enzymatic activity was found in the virulent reference strain H37Rv.

 PMID:10212111

  2. 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.

  3. Crosslink in bone collagen in Paget's disease.

    PubMed Central

    Misra, D P

    1975-01-01

    The crosslink in bone collagen was analysed in specimens of bone obtained at necropsy from cases of Paget's disease and compared with normal bone collagen of the same age. The specimens were stored at -20 degrees C before analysis. The predominant crosslink in a normal bone collagen was hydroxylysinohydroxynorleucine (di OH-LNL) (F1), which was designated syndesine in the past; another fraction, hydroxylysinorleucine (HLNL) (F2), musch less prominent than di OH-LNL, was also noted in a normal bone collagen. Both fractions were reduced in bone tissue of advancing age. The peak corresponding to HLNL was considerably increased in Paget's disease. This abnormality was constantly seen in specimens of bone from cases of Paget's disease, but the significance of the finging could not be assessed from the present investigation. Calcitonin has been shown to produce complete remission in Paget's disease and the crosslink pattern was found to be normal in specimens examined froma calcitonin-treated patient. This shows that calcitonin has some effect on the metabolism of collagen and a normal crosslink in such a situation lends support to this idea. PMID:1127123

  4. Suppression of hedgehog signaling regulates hepatic stellate cell activation and collagen secretion.

    PubMed

    Li, Tao; Leng, Xi-Sheng; Zhu, Ji-Ye; Wang, Gang

    2015-01-01

    Hepatic stellate cells (HSCs) play an important role in liver fibrosis. This study investigates the expression of hedgehog in HSC and the role of hedgehog signaling on activation and collagen secretion of HSC. Liver ex vivo perfusion with collagenase IV and density gradient centrifugation were used to isolate HSC. Expression of hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 in HSC were detected by RT-PCR. Hedgehog siRNA vectors targeting Ihh, Smo and Gli2 were constructed and transfected into HSC respectively. Suppression of hedgehog signaling were detected by SYBR Green fluorescence quantitative RT-PCR. Effects of hedgehog signaling inhibition on HSC activation and collagen I secretion were analyzed. Hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 were expressed in HSC. siRNA vectors targeting Ihh, Smo and Gli2 were successfully constructed and decreased target gene expression. Suppression of hedgehog signaling significantly decreased the expression of α-SMA in HSC (P<0.01). Collagen type I secretion of HSC were also significantly decreased (P<0.01). In summary, HSC activation and collagen secretion can be regulated by hedgehog signaling. Hedgehog may play a role in the pathogenesis of liver fibrosis.

  5. Role of side chains in collagen triple helix stabilization and partner recognition.

    PubMed

    Berisio, Rita; De Simone, Alfonso; Ruggiero, Alessia; Improta, Roberto; Vitagliano, Luigi

    2009-03-01

    Collagen is a widespread protein family involved in a variety of biological processes. The complexity of collagen and its fibrous nature prevent detailed investigations on the full-length protein. Reductionist approaches conducted by dissecting the protein complexity through the use of model peptides have proved to be quite effective. There are, however, several issues regarding structure-stability relationships, aggregation in higher-order assemblies, and partner recognition that are still extensively investigated. In this review, we discuss the role that side chains play in triple helix stabilization and in partner recognition. On the basis of recent literature data, we show that collagen triple helix stability is the result of the interplay of different factors. As a general trend, interactions established by amino/imino acid side chains within the triple helix scaffold effectively modulate the intrinsic residue propensity for this common structural motif. The use of peptide models has also highlighted the role that side chains play in collagen self-association and in its interactions with receptors. Valuable examples in these fields are illustrated. Finally, future actions required to obtain more detailed information on the structure and the function of this complex protein are also delineated.

  6. Type I collagen-mediated synthesis of noble metallic nanoparticles networks and the applications in Surface-Enhanced Raman Scattering and electrochemistry.

    PubMed

    Sun, Yujing; Sun, Lanlan; Zhang, Baohua; Xu, Fugang; Liu, Zhelin; Guo, Cunlan; Zhang, Yue; Li, Zhuang

    2009-08-15

    In this paper, we demonstrated an effective environmentally friendly synthesis route to prepare noble metallic (Au, Ag, Pt and Pd) nanoparticles (NPs) networks mediated by type I collagen in the absence of any seeds or surfactants. In the reactions, type I collagen served as stabilizing agent and assembly template for the synthesized metallic NPs. The hydrophobic interaction between collagen and mica interface as well as the hydrogen bonds between inter- and intra-collagen molecules play important roles in the formation of collagen-metallic NPs networks. The noble metallic NPs networks have many advantages in the applications of Surface-Enhanced Raman Scattering (SERS) and electrochemistry detection. Typically, the as-prepared Ag NPs networks reveal great Raman enhancement activity for 4-ATP, and can even be used to detect low concentration of DNA base, adenine, without any label step. Furthermore, the cyclic voltammograms showed Pt NPs networks have good electrocatalytic ability for the reduction of O(2).

  7. 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.

  8. 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

  9. Physical crosslinkings of edible collagen casing.

    PubMed

    Wang, Wenhang; Zhang, Yi; Ye, Ran; Ni, Yonghao

    2015-11-01

    Although edible collagen casing has been commercially used in meat industry, the safety and effectiveness of collagen cross-linking with minimally invasive treatments are still big concerns for manufacturers. In this study, ultraviolet irradiation (UV) and dehydrothermal treatment (DHT) were used to improve the properties of casing. UV, DHT, and their combination (UV+DHT) significantly increased tensile strength and decreased elongation at break of casing, in which DHT showed the best performance. Swelling of casing was also partially inhibited by the treatments. Furthermore, UV and DHT slightly improved thermal stability of the casings. In addition, X-ray diffraction patterns showed the treatments caused different extents of denaturation of collagen. No obvious effects in thickness and light transparency except for surface roughness were observed in the treated casings. The physical treatments could potentially be used as safe and effective alternatives to chemical cross-linking for the production of collage casing.

  10. [Collagenous colitis. Morphologic and immunohistochemical study].

    PubMed

    Genova, G; Arena, N; Guddo, F; Vita, C; Reitano, R; Nagar, C; Tralongo, V

    1993-01-01

    Collagenous colitis is a clinico-pathological entity characterized by chronic diarrhoeas and deposition of collagen beneath the epithelium surface of large bowel. We revised 265 endoscopy biopsy specimens of the large bowel from 198 consecutive patients with "aspecific chronic colitis". Morphometric study showed that were not significant differences among various tracts in the same patients regarding to the thickness of basament membrane. It was more than 11.9 +/- 0.49 mu only in 13 pts (6.6%), while it was 3.96 +/- 1.4 mu in the others. Immunohistochemistry study confirmed the normality of subepithelial basement membrane and the below deposition of the large quantity of collagen IV.

  11. 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…

  12. 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)

  13. 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:…

  14. Mechanical strain- and high glucose-induced alterations in mesangial cell collagen metabolism: role of TGF-beta.

    PubMed

    Riser, B L; Cortes, P; Yee, J; Sharba, A K; Asano, K; Rodriguez-Barbero, A; Narins, R G

    1998-05-01

    Cultured mesangial cells (MC) exposed to cyclic mechanical strain or high glucose levels increase their secretion of transforming growth factor-beta1 (TGF-beta1) and collagen, suggesting possible mechanisms for the development of diabetic renal sclerosis resulting from intraglomerular hypertension and/or hyperglycemia. This study examines whether glucose interacts with mechanical strain to influence collagen metabolism and whether this change is mediated by TGF-beta. Accordingly, rat MC were grown on flexible-bottom plates in 8 or 35 mM glucose media, subjected to 2 to 5 d of cyclic stretching, and assayed for TGF-beta1 mRNA, TGF-beta1 secretion, and the incorporation of 14C-proline into free or protein-associated hydroxyproline to assess the dynamics of collagen metabolism. Stretching or high glucose exposure increased TGF-beta1 secretion twofold and TGF-beta1 mRNA levels by 30 and 45%, respectively. However, the combination of these stimuli increased secretion greater than fivefold without further elevating mRNA. In 8 mM glucose medium, stretching significantly increased MC collagen synthesis and breakdown, but did not alter accumulation, whereas those stretched in 35 mM glucose markedly increased collagen accumulation. TGF-beta neutralization significantly reduced baseline collagen synthesis, breakdown, and accumulation in low glucose, but had no significant effect on the changes induced by stretch. In contrast, the same treatment of MC in high glucose medium greatly reduced stretch-induced synthesis and breakdown of collagen and totally abolished the increase in collagen accumulation. These results indicate that TGF-beta plays a positive regulatory role in MC collagen synthesis, breakdown, and accumulation. However, in low glucose there is no stretch-induced collagen accumulation, and the effect of TGF-beta is limited to basal collagen turnover. In high glucose media, TGF-beta is a critical mediator of stretch-induced collagen synthesis and catabolism, and

  15. Prospects and limitations of the rational engineering of fibrillar collagens

    PubMed Central

    Majsterek, Ireneusz; McAdams, Erin; Adachi, Eijiro; Dhume, Shirish T.; Fertala, Andrzej

    2003-01-01

    Recombinant collagens are attractive proteins for a number of biomedical applications. To date, significant progress was made in the large-scale production of nonmodified recombinant collagens; however, engineering of novel collagen-like proteins according to customized specifications has not been addressed. Herein we investigated the possibility of rational engineering of collagen-like proteins with specifically assigned characteristics. We have genetically engineered two DNA constructs encoding multi-D4 collagens defined as collagen-like proteins, consisting primarily of a tandem of the collagen II D4 periods that correspond to the biologically active region. We have also attempted to decrease enzymatic degradation of novel collagen by mutating a matrix metalloproteinase 1 cleavage site present in the D4 period. We demonstrated that the recombinant collagen α-chains consisting predominantly of the D4 period but lacking most of the other D periods found in native collagen fold into a typical collagen triple helix, and the novel procollagens are correctly processed by procollagen N-proteinase and procollagen C-proteinase. The nonmutated multi-D4 collagen had a normal melting point of 41°C and a similar carbohydrate content as that of control. In contrast, the mutant multi-D4 collagen had a markedly lower thermostability of 36°C and a significantly higher carbohydrate content. Both collagens were cleaved at multiple sites by matrix metalloproteinase 1, but the rate of hydrolysis of the mutant multi-D4 collagen was lower. These results provide a basis for the rational engineering of collagenous proteins and identifying any undesirable consequences of altering the collagenous amino acid sequences. PMID:12931004

  16. Cell-collagen interactions: the use of peptide Toolkits to investigate collagen-receptor interactions.

    PubMed

    Farndale, Richard W; Lisman, Ton; Bihan, Dominique; Hamaia, Samir; Smerling, Christiane S; Pugh, Nicholas; Konitsiotis, Antonios; Leitinger, Birgit; de Groot, Philip G; Jarvis, Gavin E; Raynal, Nicolas

    2008-04-01

    Fibrillar collagens provide the most fundamental platform in the vertebrate organism for the attachment of cells and matrix molecules. We have identified specific sites in collagens to which cells can attach, either directly or through protein intermediaries. Using Toolkits of triple-helical peptides, each peptide comprising 27 residues of collagen primary sequence and overlapping with its neighbours by nine amino acids, we have mapped the binding of receptors and other proteins on to collagens II or III. Integrin alpha2beta1 binds to several GXX'GER motifs within the collagens, the affinities of which differ sufficiently to control cell adhesion and migration independently of the cellular regulation of the integrin. The platelet receptor, Gp (glycoprotein) VI binds well to GPO (where O is hydroxyproline)-containing model peptides, but to very few Toolkit peptides, suggesting that sequence in addition to GPO triplets is important in defining GpVI binding. The Toolkits have been applied to the plasma protein vWF (von Willebrand factor), which binds to only a single sequence, identified by truncation and amino acid substitution within Toolkit peptides, as GXRGQOGVMGFO in collagens II and III. Intriguingly, the receptor tyrosine kinase, DDR2 (discoidin domain receptor 2) recognizes three sites in collagen II, including its vWF-binding site, although the amino acids that support the interaction differ slightly within this motif. Furthermore, the secreted protein BM-40 (basement membrane protein 40) also binds well to this same region. Thus the availability of extracellular collagen-binding proteins may be important in regulating and facilitating direct collagen-receptor interaction.

  17. Ordered collagen membranes: production and characterization.

    PubMed

    Ruderman, G; Mogilner, I G; Tolosa, E J; Massa, N; Garavaglia, M; Grigera, J R

    2012-01-01

    A collagen membrane with microscopic order is presented. The membranes were produced with acid-soluble collagen, using two different methods to obtain orientation. The product was characterized by mean of UV and IR spectra, scanning electronic microscopy, optical microscopy and laser diffractometry. The results clearly show a high level of order in the membranes obtained by both techniques. Permeability for rifamycin, ascorbic acid and NaCl was also measured. Due to the characteristics of the membranes, they have a potential application for treatment of surface injuries.

  18. Platelet-reactive sites in collagen. Collagens I and III possess different aggregatory sites.

    PubMed Central

    Morton, L F; Fitzsimmons, C M; Rauterberg, J; Barnes, M J

    1987-01-01

    Collagen type III possesses a highly reactive platelet-aggregatory site at a locus which in type I is essentially inactive whilst the latter collagen possesses reactive sites absent in type III. It is proposed that platelet aggregation by collagen involves the sequence GK[or R]PG(EY)GPK[or R]G(EY) or, less favourably, GPK[or R]G(EY)G(XY)GK[or R]PG(EY), one basic residue acting in combination with the second in an adjacent alpha-chain. PMID:3124815

  19. In situ time-series monitoring of collagen fibers produced by standing-cultured osteoblasts using a second-harmonic-generation microscope.

    PubMed

    Hase, Eiji; Matsubara, Oki; Minamikawa, Takeo; Sato, Katsuya; Yasui, Takeshi

    2016-04-20

    In bone tissue engineering and regeneration, there is a considerable need for an unstained method of monitoring collagen fibers produced by osteoblasts. This is because collagen fibers play an important role as a bone matrix and continuous monitoring of their temporal dynamics is important in clarifying the organization process toward forming bone tissue. In the work described here, using a second-harmonic-generation (SHG) microscope, we performed in situ time-series monitoring of collagen fibers produced by cultured osteoblasts without the need for staining. Use of the 19 fs near-infrared pulsed light enables us to visualize the temporal dynamics in a thin layer of collagen fibers produced by a single layer of osteoblasts in high-contrast SHG images. While the collagen fibers were produced and stored inside the osteoblasts at an early stage of culturing, the network structure of collagen fibers was formed and locally condensed at a late stage. Furthermore, we extracted a quantitative parameter of collagen maturity degree in the cultured sample by use of image analysis based on a two-dimensional Fourier transform of the SHG image. The proposed method will be useful for in situ quality and quantity control of collagen fibers in bone tissue engineering and regeneration.

  20. Fibroblast migration and collagen deposition during dermal wound healing: mathematical modelling and clinical implications.

    PubMed

    McDougall, Steven; Dallon, John; Sherratt, Jonathan; Maini, Philip

    2006-06-15

    The extent to which collagen alignment occurs during dermal wound healing determines the severity of scar tissue formation. We have modelled this using a multiscale approach, in which extracellular materials, for example collagen and fibrin, are modelled as continua, while fibroblasts are considered as discrete units. Within this model framework, we have explored the effects that different parameters have on the alignment process, and we have used the model to investigate how manipulation of transforming growth factor-beta levels can reduce scar tissue formation. We briefly review this body of work, then extend the modelling framework to investigate the role played by leucocyte signalling in wound repair. To this end, fibroblast migration and collagen deposition within both the wound region and healthy peripheral tissue are considered. Trajectories of individual fibroblasts are determined as they migrate towards the wound region under the combined influence of collagen/fibrin alignment and gradients in a paracrine chemoattractant produced by leucocytes. The effects of a number of different physiological and cellular parameters upon the collagen alignment and repair integrity are assessed. These parameters include fibroblast concentration, cellular speed, fibroblast sensitivity to chemoattractant concentration and chemoattractant diffusion coefficient. Our results show that chemoattractant gradients lead to increased collagen alignment at the interface between the wound and the healthy tissue. Results show that there is a trade-off between wound integrity and the degree of scarring. The former is found to be optimized under conditions of a large chemoattractant diffusion coefficient, while the latter can be minimized when repair takes place in the presence of a competitive inhibitor to chemoattractants.

  1. Mechanical interactions between collagen and proteoglycans: implications for the stability of lung tissue.

    PubMed

    Cavalcante, Francisco S A; Ito, Satoru; Brewer, Kelly; Sakai, Hiroaki; Alencar, Adriano M; Almeida, Murilo P; Andrade, José S; Majumdar, Arnab; Ingenito, Edward P; Suki, Béla

    2005-02-01

    Collagen and elastin are thought to dominate the elasticity of the connective tissue including lung parenchyma. The glycosaminoglycans on the proteoglycans may also play a role because osmolarity of interstitial fluid can alter the repulsive forces on the negatively charged glycosaminoglycans, allowing them to collapse or inflate, which can affect the stretching and folding pattern of the fibers. Hence, we hypothesized that the elasticity of lung tissue arises primarily from 1) the topology of the collagen-elastin network and 2) the mechanical interaction between proteoglycans and fibers. We measured the quasi-static, uniaxial stress-strain curves of lung tissue sheets in hypotonic, normal, and hypertonic solutions. We found that the stress-strain curve was sensitive to osmolarity, but this sensitivity decreased after proteoglycan digestion. Images of immunofluorescently labeled collagen networks showed that the fibers follow the alveolar walls that form a hexagonal-like structure. Despite the large heterogeneity, the aspect ratio of the hexagons at 30% uniaxial strain increased linearly with osmolarity. We developed a two-dimensional hexagonal network model of the alveolar structure incorporating the mechanical properties of the collagen-elastin fibers and their interaction with proteoglycans. The model accounted for the stress-strain curves observed under all experimental conditions. The model also predicted how aspect ratio changed with osmolarity and strain, which allowed us to estimate the Young's modulus of a single alveolar wall and a collagen fiber. We therefore identify a novel and important role for the proteoglycans: they stabilize the collagen-elastin network of connective tissues and contribute to lung elasticity and alveolar stability at low to medium lung volumes.

  2. Influence of different crosslinking treatments on the physical properties of collagen membranes.

    PubMed

    Charulatha, V; Rajaram, A

    2003-02-01

    The physical properties of collagen-based biomaterials are profoundly influenced by the method and extent of crosslinking. In this study, the influence of various crosslinking treatments on the physical properties of reconstituted collagen membranes was assessed. Five crosslinking agents viz., GTA, DMS, DTBP, a combination of DMS and GTA and acyl azide method were used to stabilize collagen matrices. Crosslinking density, swelling ratio, thermo-mechanical properties, stress-strain characteristics and resistance to collagenase digestion were determined to evaluate the physical properties of crosslinked matrices. GTA treatment induced the maximum number of crosslinks (13) while DMS treatment induced the minimum (7). Of the two diimidoesters (DMS and DTBP), DTBP was a more effective crosslinking agent due to the presence of disulphide bonds in the DTBP crosslinks. T(s) for DTBP and DMS crosslinked collagen were 80 degrees C and 70 degrees C, and their HIT values were 5.4 and 2.85MN/m(2), respectively. Low concentration of GTA (0.01%) increased the crosslinking density of an already crosslinked matrix (DMS treated matrix) from 7 to 12. Lowest fracture energy was observed for the acyl azide treated matrix (0.61MJ/m(3)) while the highest was observed for the GTA treated matrix (1.97MJ/m(3)). The tensile strength of GTA treated matrix was maximum (12.4MPa) and that of acyl azide treated matrix was minimum (7.2MPa). GTA, DTBP and acyl azide treated matrices were equally resistant to collagenase degradation with approximately 6% solubilization after 5h while the DMS treated was least stable with 52.4% solubilization after the same time period. The spatial orientation of amino acid side chain residues on collagen plays an important role in determining the crosslinking density and consequent physical properties of the collagen matrix.

  3. Limb-brightening observations from the OSO-7 satellite. II - Comparison of Abel-inverted intensities of Fe XIV and Fe XIII EUV emission lines with predictions

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.; Rothe, E. D.; Neupert, W. M.

    1976-01-01

    Intensities of Fe XIV and Fe XIII EUV emission lines obtained at coronal locations beyond the limb by the Goddard spectroheliograph on the OSO 7 satellite have been corrected for the wavelength dependence of the instrument's sensitivity and have been Abel-inverted to provide a valid comparison with theoretical predictions for each ion. Details of the Abel-inversion procedure are given, including explicit formulas for application of Bracewell's (1956) method. The intensity ratios of pairs of lines originating from a common level are compared with expected theoretical transition probability ratios over a range of heliocentric distance; deviations in some cases yield information about adjacent unclassified lines. Comparison of the observations with predictions for Fe XIV and Fe XIII shows generally good agreement, with a few interesting discrepancies that may imply a corresponding need for more accurate collisional excitation cross sections. The same comparison yields the variation of electron density with heliocentric radius for each ion separately; the two density functions are found to agree within a factor of three.

  4. 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…

  5. 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…

  6. Play: Children's Context for Development.

    ERIC Educational Resources Information Center

    Klein, Tovah P.; Wirth, Daniele; Linas, Keri

    2003-01-01

    Defines the elements of play, illuminating its central role in young children's learning and development. Focuses on how play experiences contribute to children's independence in negotiating, its role in keeping children involved, and the play-reality distinction. Offers suggestions to teachers for facilitating and supporting children's play,…

  7. 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

  8. Epigallocatechin-3-gallate, a polyphenol component of green tea, suppresses both collagen production and collagenase activity in hepatic stellate cells.

    PubMed

    Nakamuta, Makoto; Higashi, Nobuhiko; Kohjima, Motoyuki; Fukushima, Marie; Ohta, Satoshi; Kotoh, Kazuhiro; Kobayashi, Naoya; Enjoji, Munechika

    2005-10-01

    Catechins such as epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG), and epigallocatechin (EGC) are polyphenol components of green tea. EGCG is the major component and has been reported to possess a wide range of biological properties including anti-fibrogenic activity. In hepatic fibrosis, activated hepatic stellate cells (HSCs) play a central role. In this study, we investigated the effect of catechins, including EGCG, on collagen production and collagenase activity in rat primary HSCs and activated human HSC-derived TWNT-4 cells. EGCG (50 microM) suppressed type I collagen production in rat HSCs more than ECG (50 microM) did; however, EGC (50 microM) did not show suppressive effects. EGCG also inhibited both collagen production and collagenase activity (active matrix metalloproteinase-1 [MMP-1]) in a dose-dependent manner, but did not affect the tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) production in TWNT-4 cells. Real-time PCR unexpectedly revealed that EGCG enhanced the transcription of type I collagen and TIMP-1, but did not affect the transcription of alpha-smooth muscle actin (alpha-SMA), and reduced the transcription MMP-1 in TWNT-4 cells. These findings demonstrated that EGCG inhibited collagen production regardless of enhanced collagen transcription and suppressed collagenase activity, and suggested that EGCG might have therapeutic potential for liver fibrosis.

  9. 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.

  10. 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

  11. Localization of pro-alpha 2(V) collagen transcripts in the tissues of the developing mouse embryo.

    PubMed

    Andrikopoulos, K; Suzuki, H R; Solursh, M; Ramirez, F

    1992-10-01

    Correct assembly of fibrillar collagen networks plays a critical role in animal morphogenesis. Very little is known about the contribution of the so-called minor fibrillar collagens (types V and XI) to fibrillogenesis. Here we examined the developmental expression of the mouse pro-alpha 2(V) collagen gene (col5a2) after the cloning and sequencing of cDNAs that cover the entire length of the message. Transcripts of col5a2, detectable as early as 9 days of gestation, localize with distinct patterns in the tissues of day 12.5 and day 16.5 fetuses. The earlier developmental stage is characterized by low and diffuse col5a2 expression in the peritoneal membranes and intestinal and craniofacial mesenchymes. The later stage exhibits higher and more restricted col5a2 mRNA accumulation in primary ossified regions, perichondrium, joints, tendon, atrioventricular valve of the heart, and selected portions of the head. A parallel analysis using a cartilage-specific pro-alpha 1(II) collagen (col2a1) probe confirmed that these two collagen genes are transcribed in a mutually exclusive manner during mouse embryogenesis. On the other hand, the developmental pattern of col5a2 expression closely resembles that of the type I collagen, thus further substantiating the notion that these macromolecules cooperate in the formation of fibrillar networks in non-cartilaginous matrices.

  12. 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.

  13. SPARC regulates collagen interaction with cardiac fibroblast cell surfaces.

    PubMed

    Harris, Brett S; Zhang, Yuhua; Card, Lauren; Rivera, Lee B; Brekken, Rolf A; Bradshaw, Amy D

    2011-09-01

    Cardiac tissue from mice that do not express secreted protein acidic and rich in cysteine (SPARC) have reduced amounts of insoluble collagen content at baseline and in response to pressure overload hypertrophy compared with wild-type (WT) mice. However, the cellular mechanism by which SPARC affects myocardial collagen is not clearly defined. Although expression of SPARC by cardiac myocytes has been detected in vitro, immunohistochemistry of hearts demonstrated SPARC staining primarily associated with interstitial fibroblastic cells. Primary cardiac fibroblasts isolated from SPARC-null and WT mice were assayed for collagen I synthesis by [(3)H]proline incorporation into procollagen and by immunoblot analysis of procollagen processing. Bacterial collagenase was used to discern intracellular from extracellular forms of collagen I. Increased amounts of collagen I were found associated with SPARC-null versus WT cells, and the proportion of total collagen I detected on SPARC-null fibroblasts without propeptides [collagen-α(1)(I)] was higher than in WT cells. In addition, the amount of total collagen sensitive to collagenase digestion (extracellular) was greater in SPARC-null cells than in WT cells, indicating an increase in cell surface-associated collagen in the absence of SPARC. Furthermore, higher levels of collagen type V, a fibrillar collagen implicated in collagen fibril initiation, were found in SPARC-null fibroblasts. The absence of SPARC did not result in significant differences in proliferation or in decreased production of procollagen I by cardiac fibroblasts. We conclude that SPARC regulates collagen in the heart by modulating procollagen processing and interactions with fibroblast cell surfaces. These results are consistent with decreased levels of interstitial collagen in the hearts of SPARC-null mice being due primarily to inefficient collagen deposition into the extracellular matrix rather than to differences in collagen production.

  14. 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.

  15. Conformational stability of triazolyl functionalized collagen triple helices.

    PubMed

    Erdmann, Roman S; Wennemers, Helma

    2013-06-15

    Functionalized collagen is attractive for the development of synthetic biomaterials. Herein we present the functionalization of azidoproline containing collagen model peptides with various alkynes using click chemistry. The influence on the stability of the collagen triple helix of the stereochemistry of the introduced triazolyl prolines (4R or 4S), the position of their incorporation (Xaa or Yaa) and the substituents attached to them are shown. The results provide a useful guide for the optimal functionalization of collagen using click chemistry.

  16. Rough and Tumble Play 101

    ERIC Educational Resources Information Center

    Carlson, Frances

    2009-01-01

    Many people fear that play-fighting or rough and tumble play is the same as real fighting. There is also a fear that this rough play will become real fighting if allowed to continue. Most of all, parents and teachers fear that during the course of rough and tumble play a child may be hurt. To provide for and allow children to play rough without…

  17. 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.

  18. Collagen Fiber Orientation in Primate Long Bones.

    PubMed

    Warshaw, Johanna; Bromage, Timothy G; Terranova, Carl J; Enlow, Donald H

    2017-02-16

    Studies of variation in orientation of collagen fibers within bone have lead to the proposition that these are preferentially aligned to accommodate different kinds of load, with tension best resisted by fibers aligned longitudinally relative to the load, and compression best resisted by transversely aligned fibers. However, previous studies have often neglected to consider the effect of developmental processes, including constraints on collagen fiber orientation (CFO), particularly in primary bone. Here we use circularly polarized light microscopy to examine patterns of CFO in cross-sections from the midshaft femur, humerus, tibia, radius and ulna in a range of living primate taxa with varied body sizes, phylogenetic relationships and positional behaviors. We find that a preponderance of longitudinally oriented collagen is characteristic of both periosteal primary and intracortically remodeled bone. Where variation does occur among groups, it is not simply understood via interpretations of mechanical loads, although prioritized adaptations to tension and/or shear are considered. While there is some suggestion that CFO may correlate with body size, this relationship is neither consistent nor easily explicable through consideration of size-related changes in mechanical adaptation. The results of our study indicate that there is no clear relationship between CFO and phylogenetic status. One of the principle factors accounting for the range of variation that does exist is primary tissue type, where slower depositing bone is more likely to comprise a larger proportion of oblique to transverse collagen fibers. This article is protected by copyright. All rights reserved.

  19. 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.

  20. Collagen network strengthening following cyclic tensile loading.

    PubMed

    Susilo, Monica E; Paten, Jeffrey A; Sander, Edward A; Nguyen, Thao D; Ruberti, Jeffrey W

    2016-02-06

    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.

  1. Controlled self assembly of collagen nanoparticle

    NASA Astrophysics Data System (ADS)

    Papi, Massimiliano; Palmieri, Valentina; Maulucci, Giuseppe; Arcovito, Giuseppe; Greco, Emanuela; Quintiliani, Gianluca; Fraziano, Maurizio; De Spirito, Marco

    2011-11-01

    In recent years carrier-mediated drug delivery has emerged as a powerful methodology for the treatment of various pathologies. The therapeutic index of traditional and novel drugs is enhanced via the increase of specificity due to targeting of drugs to a particular tissue, cell or intracellular compartment, the control over release kinetics, the protection of the active agent, or a combination of the above. Collagen is an important biomaterial in medical applications and ideal as protein-based drug delivery platform due to its special characteristics, such as biocompatibility, low toxicity, biodegradability, and weak antigenicity. While some many attempts have been made, further work is needed to produce fully biocompatible collagen hydrogels of desired size and able to release drugs on a specific target. In this article we propose a novel method to obtain spherical particles made of polymerized collagen surrounded by DMPC liposomes. The liposomes allow to control both the particles dimension and the gelling environment during the collagen polymerization. Furthermore, an optical based method to visualize and quantify each step of the proposed protocol is detailed and discussed.

  2. Imaging Prostate Cancer Microenvironment by Collagen Hybridization

    DTIC Science & Technology

    2013-10-01

    Dyn. 237, 2607−2621. (3) von der Mark, H., von der Mark, K., and Gay , S. (1976) Study of differential collagen synthesis during development of the...GFP encoding plasmid DNA through electrostatic interactions and enhance gene transfection (adapted from Ref. [52]). www.sciencedirect.com Current

  3. Autoantibodies and immunoglobulins in collagenous colitis.

    PubMed Central

    Bohr, J; Tysk, C; Yang, P; Danielsson, D; Järnerot, G

    1996-01-01

    BACKGROUND: The aetiology and pathogenesis of collagenous colitis are unknown. Autoimmunity has been suggested, but no serological findings have supported such a theory. AIMS AND METHODS: Serum from 38 collagenous colitis patients and 38 matched healthy controls was analysed for autoantibodies--that is, antinuclear antibodies, antineutrophil cytoplasmic antibodies, smooth muscle and mitochondrial antibodies, rheumatoid factor and antibodies to thyroglobulin and microsomal antigen, together with antibodies to endomysium, gliadin, and cardiolipin. The serum values of IgA, IgG, IgM, and IgG-subclasses, and complement factors C3 and C4 were also determined. RESULTS: In patients with collagenous colitis the mean value of IgM was significantly increased 2.5 g/l (95% CI; 1.9, 3.2) compared with 1.4 g/l (95% CI; 1.2, 1.7) in controls (p = 0.002). Antinuclear antibodies occurred in nine of 38 patients compared with three of 38 controls, this difference was not statistically significant (p = 0.11). The results of all other immunoglobulins, complement factors, and specific antibodies showed no statistical difference between patients and controls. CONCLUSIONS: No firm evidence for an autoimmune genesis in collagenous colitis is found in this study, although the findings of a positive ANA-titre in some patients and an increased IgM level might give some support for this hypothesis. PMID:8881813

  4. 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

    2015-08-20

    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. Collagen binding specificity of the discoidin domain receptors: binding sites on collagens II and III and molecular determinants for collagen IV recognition by DDR1.

    PubMed

    Xu, Huifang; Raynal, Nicolas; Stathopoulos, Stavros; Myllyharju, Johanna; Farndale, Richard W; Leitinger, Birgit

    2011-01-01

    The discoidin domain receptors, DDR1 and DDR2 are cell surface receptor tyrosine kinases that are activated by triple-helical collagen. While normal DDR signalling regulates fundamental cellular processes, aberrant DDR signalling is associated with several human diseases. We previously identified GVMGFO (O is hydroxyproline) as a major DDR2 binding site in collagens I-III, and located two additional DDR2 binding sites in collagen II. Here we extend these studies to the homologous DDR1 and the identification of DDR binding sites on collagen III. Using sets of overlapping triple-helical peptides, the Collagen II and Collagen III Toolkits, we located several DDR2 binding sites on both collagens. The interaction of DDR1 with Toolkit peptides was more restricted, with DDR1 mainly binding to peptides containing the GVMGFO motif. Triple-helical peptides containing the GVMGFO motif induced DDR1 transmembrane signalling, and DDR1 binding and receptor activation occurred with the same amino acid requirements as previously defined for DDR2. While both DDRs exhibit the same specificity for binding the GVMGFO motif, which is present only in fibrillar collagens, the two receptors display distinct preferences for certain non-fibrillar collagens, with the basement membrane collagen IV being exclusively recognised by DDR1. Based on our recent crystal structure of a DDR2-collagen complex, we designed mutations to identify the molecular determinants for DDR1 binding to collagen IV. By replacing five amino acids in DDR2 with the corresponding DDR1 residues we were able to create a DDR2 construct that could function as a collagen IV receptor.

  7. 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

  8. 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

  9. Microscale Mechanical Testing of Individual Collagen Fibers

    NASA Astrophysics Data System (ADS)

    Poissant, Jeffrey

    Collagen is a key constituent for a large number of biological materials including bone, tendon, cartilage, skin and fish scales. Understanding the mechanical behavior of collagen's microscale structural components (fibers and fibrils) is therefore of utmost importance for fields such as biomimetics and biomedical engineering. However, the mechanics of collagen fibers and fibrils remain largely unexplored. The main research challenges are the small sample sizes (diameters less than 1 im) and the need to maintain physiologically relevant conditions. In this work, a microscale mechanical testing device (MMTD) capable of measuring the stress-strain response of individual collagen fibers and fibrils was developed. The MMTD consists of: (i) a transducer from a commercial nanoindenter to measure load and displacement, (ii) an optical microscope to observe the deformation of the sample in-situ and (iii) micromanipulators to isolate, position and fix samples. Collagen fibers and fibrils were extracted from fish scales using a novel dissection procedure and tested using the MMTD. A variety of tensile tests were performed including monotonic loading and cyclic tests with increasing loading rate or maximum displacement. The monotonic test results found that the elastic modulus, ultimate tensile strength and strain at failure range from 0.5 to 1.3 GPa, 100 to 200 MPa and 20% to 60%, respectively. The cyclic tests revealed that the largest increase in damage accumulation occurs at strains between 10% and 20%, when hydrogen bonds at the molecular level are ruptured. Further straining the fibril causes little additional damage accumulation and signals the approach of failure. The addition of water is shown to increase damage tolerance and strain to failure.

  10. Mechanically overloading collagen fibrils uncoils collagen molecules, placing them in a stable, denatured state.

    PubMed

    Veres, Samuel P; Harrison, Julia M; Lee, J Michael

    2014-01-01

    Due to the high occurrence rate of overextension injuries to tendons and ligaments, it is important to understand the fundamental mechanisms of damage to these tissues' primary load-bearing elements: collagen fibrils and their constituent molecules. Based on our recent observations of a new subrupture, overload-induced mode of fibril disruption that we call discrete plasticity, we have sought in the current study to re-explore whether the tensile overload of collagen fibrils can alter the helical conformation of collagen molecules. In order to accomplish this, we have analyzed the conformation of collagen molecules within repeatedly overloaded tendons in relation to their undamaged matched-pair controls using both differential scanning calorimetry and variable temperature trypsin digestion susceptibility. We find that tensile overload reduces the specific enthalpy of denaturation of tendons, and increases their susceptibility to trypsin digestion, even when the digestion is carried out at temperatures as low as 4 °C. Our results indicate that the tensile overload of collagen fibrils can uncoil the helix of collagen molecules, placing them in a stable, denatured state.

  11. Play technique in psychodynamic psychotherapy.

    PubMed

    Yanof, Judith A

    2013-04-01

    Imaginary play is often a child's best way of communicating affects, fantasies, and internal states. In play children are freer to express their forbidden and conflicted thoughts. Consequently, one of the best ways for the therapist to enter the child's world is to do so from within the displacement of the play process. For children who cannot play, the therapist's goal is to teach the child to use play as a means of communication and to create meaning. This article present clinical examples to illustrate how the author uses play in the clinical situation.

  12. 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...

  13. Characterization of muscle epimysium, perimysium and endomysium collagens.

    PubMed Central

    Light, N; Champion, A E

    1984-01-01

    In the past it has been proven difficult to separate and characterize collagen from muscle because of its relative paucity in this tissue. The present report presents a comprehensive methodology, combining methods previously described by McCollester [(1962) Biochim. Biophys. Acta 57, 427-437] and Laurent, Cockerill, McAnulty & Hastings [(1981) Anal. Biochem. 113, 301-312], in which the three major tracts of muscle connective tissue, the epimysium, perimysium and endomysium, may be prepared and separated from the bulk of muscle protein. Connective tissue thus prepared may be washed with salt and treated with pepsin to liberate soluble native collagen, or can be washed with sodium dodecyl sulphate to produce a very clean insoluble collagenous product. This latter type of preparation may be used for quantification of the ratio of the major genetic forms of collagen or for measurement of reducible cross-link content to give reproducible results. It was shown that both the epimysium and perimysium contain type I collagen as the major component and type III collagen as a minor component; perimysium also contained traces of type V collagen. The endomysium, the sheaths of individual muscle fibres, was shown to contain both type I and type III collagen as major components. Type V collagen was also present in small amounts, and type IV collagen, the collagenous component of basement membranes, was purified from endomysial preparations. This is the first biochemical demonstration of the presence of type IV collagen in muscle endomysium. The preparation was shown to be very similar to other type IV collagens from other basement membranes on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and was indistinguishable from EHS sarcoma collagen and placenta type IV collagen in the electron microscope after rotary shadowing. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:6743238

  14. Effect of oxy radicals on several types of collagen.

    PubMed

    Monboisse, J C; Poulin, G; Braquet, P; Randoux, A; Ferradini, C; Borel, J P

    1984-01-01

    Fibrils of collagen reconstituted in vitro by dialysis against sodium formate are exposed to free oxy radicals generated by three different systems: (i) xanthine oxidase + hypoxanthine, (ii) gamma-rays originating from a cobalt bomb; (iii) pulse radiolysis in a particle accelerator. A degradation of the collagen fibres is demonstrated by determination of the amount of hydroxyproline-containing peptides in the supernatant after incubation. Types I and III collagen are sensitive to the effect, whereas type V collagen is not. The effect persists when collagen is specially delipidated.

  15. Second harmonic imaging and scoring of collagen in fibrotic tissues

    NASA Astrophysics Data System (ADS)

    Strupler, M.; Pena, A.-M.; Hernest, M.; Tharaux, P.-L.; Martin, J.-L.; Beaurepaire, E.; Schanne-Klein, M.-C.

    2007-04-01

    We compare second harmonic generation (SHG) to histological and immunohistochemical techniques for the visualization and scoring of collagen in biological tissues. We show that SHG microscopy is highly specific for fibrillar collagens and that combined SHG and two-photon excited fluorescence (2PEF) imaging can provide simultaneous three-dimensional visualization of collagen synthesis and assembly sites in transgenic animal models expressing GFP constructs. Finally, we propose several scores for characterizing collagen accumulation based on SHG images and appropriate for different types of collagen distributions. We illustrate the sensitivity of these scores in a murine model of renal fibrosis using a morphological segmentation of the tissue based on endogenous 2PEF signals.

  16. Calcific Aortic Valve Disease Is Associated with Layer-Specific Alterations in Collagen Architecture

    PubMed Central

    Hutson, Heather N.; Marohl, Taylor; Anderson, Matthew; Eliceiri, Kevin; Campagnola, Paul

    2016-01-01

    Disorganization of the valve extracellular matrix (ECM) is a hallmark of calcific aortic valve disease (CAVD). However, while microarchitectural features of the ECM can strongly influence the biological and mechanical behavior of tissues, little is known about the ECM microarchitecture in CAVD. In this work, we apply advanced imaging techniques to quantify spatially heterogeneous changes in collagen microarchitecture in CAVD. Human aortic valves were obtained from individuals between 50 and 75 years old with no evidence of valvular disease (healthy) and individuals who underwent valve replacement surgery due to severe stenosis (diseased). Second Harmonic Generation microscopy and subsequent image quantification revealed layer-specific changes in fiber characteristics in healthy and diseased valves. Specifically, the majority of collagen fiber changes in CAVD were found to occur in the spongiosa, where collagen fiber number increased by over 2-fold, and fiber width and density also significantly increased. Relatively few fibrillar changes occurred in the fibrosa in CAVD, where fibers became significantly shorter, but did not otherwise change in terms of number, width, density, or alignment. Immunohistochemical staining for lysyl oxidase showed localized increased expression in the diseased fibrosa. These findings reveal a more complex picture of valvular collagen enrichment and arrangement in CAVD than has previously been described using traditional analysis methods. Changes in fiber architecture may play a role in regulating the pathobiological events and mechanical properties of valves during CAVD. Additionally, characterization of the ECM microarchitecture can inform the design of fibrous scaffolds for heart valve tissue engineering. PMID:27685946

  17. 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.

  18. 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.

  19. Problematic game play: the diagnostic value of playing motives, passion, and playing time in men.

    PubMed

    Kneer, Julia; Rieger, Diana

    2015-04-30

    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.

  20. 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

  1. Interaction study of collagen and sericin in blending solution.

    PubMed

    Duan, Lian; Yuan, Jingjie; Yang, Xiao; Cheng, Xinjian; Li, Jiao

    2016-12-01

    The interactions of collagen and sericin were studied by fluorescence spectra, ultraviolet spectra, FTIR spectra and dynamic light scattering. The fluorescence quenching in emission spectra and red-shift (283-330nm) in synchronous fluorescence spectra suggested the Tyr of collagen and sericin overlapped with a distance of 3Å, generating excimer. The overlapped Tyr of collagen and sericin decreased the hydrophobicity of collagen, which resulted in the red-shifts (233-240nm) in ultraviolet spectra. Moreover, the red-shifts of amide bands of collagen in FTIR spectra indicated the hydrogen bonds of collagen were weaken and it could also be explained by the overlapped Tyr. The results of 2D-FTIR spectra demonstrated the backbone of collagen molecule was varied and the most susceptible structure of collagen was the triple helix with the presence of sericin. Based on dynamic light scattering, we conjectured large pure collagen aggregates were replaced by hybrid aggregates of collagen and sericin particles after the addition of sericin. With ascending sericin ratio, the diameters of the hybrid aggregates increased and attained maximum with 60% ratio of sericin, which were on account of the increasing excimer number. The results of DSC demonstrated the presence of sericin enhanced the thermal stability of collagen.

  2. 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.

  3. Physical and chemical modifications of collagen gels: impact on diffusion.

    PubMed

    Erikson, Arne; Andersen, Hilde Nortvedt; Naess, Stine Nalum; Sikorski, Pawel; Davies, Catharina de Lange

    2008-02-01

    The extracellular matrix (ECM) represents a major barrier for delivery of therapeutic drugs, and the transport is determined by the ECM composition, structure, and distribution. Because of the high interstitial fluid pressure in tumors, diffusion becomes the main transport mechanism through ECM. The purpose of this work was to study the impact of the structure of the collagen network on diffusion, by studying to what extent the orientation and chemical modification of the collagen network influenced diffusion. Collagen gels with a concentration of 0.2-2.0% that is comparable with the amount of collagen in the tumor ECM were used as a model system for ECM. Collagen gels were aligned in a low-strength magnetic field and geometrical confinement, and chemically modified by adding decorin or hyaluronan. Diffusion of dextran 2-MDa molecules in the collagen gels was measured using fluorescence recovery after photobleaching. Alignment of the collagen fibers in our gels was found to have no impact on the diffusion coefficient. Adding decorin reduced the diameter of the collagen fibers, but no effect on diffusion was observed. Hyaluronan also reduced the fiber diameter, and high concentration of hyaluronan (2.5 mg/ml) increased the diffusion coefficient. The results indicate that the structure of the collagen network is not a major factor in determining the diffusion through the ECM. Rather, increasing the concentration of collagen was found to reduce the diffusion coefficient. Concentration of the collagen network is more important than the structure in determining the diffusion coefficient.

  4. 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.

  5. 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…

  6. 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…

  7. 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…

  8. The Values of Outdoor Play

    ERIC Educational Resources Information Center

    Elkind, David

    2006-01-01

    This article describes outdoor play as a solid foundation and a central vehicle of knowledge about the real world. Outdoor play is important to all age levels, but particularly in early childhood and the elementary years. Children's outdoor play is not a luxury. It is critical in children's ability to learn about the world, others, and themselves.…

  9. Piaget, Play and Cognition, Revisited.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Piaget's early contribution to theorizing about play is discussed critically with reference to three major interrelated problems. These are: (1) that despite their equipotentiality in Piaget's theory of intelligence, imitation and play are not conceptualized as making an equal contribution to cognition, play taking a subordinate role; (2) that…

  10. 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…

  11. 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…

  12. Transdermal Delivery of Functional Collagen Via Polyvinylpyrrolidone Microneedles

    PubMed Central

    Sun, Wenchao; Inayathullah, Mohammed; Manoukian, Martin A. C.; Malkovskiy, Andrey V.; Manickam, Sathish; Marinkovich, M. Peter; Lane, Alfred T.; Tayebi, Lobat; Seifalian, Alexander M.; Rajadas, Jayakumar

    2017-01-01

    Collagen makes up a large proportion of the human body, particularly the skin. As the body ages, collagen content decreases, resulting in wrinkled skin and decreased wound healing capabilities. This paper presents a method of delivering type I collagen into porcine and human skin utilizing a polyvinylpyrrolidone microneedle delivery system. The microneedle patches were made with concentrations of 1, 2, 4, and 8% type I collagen (w/w). Microneedle structures and the distribution of collagen were characterized using scanning electron microscopy and confocal microscopy. Patches were then applied on the porcine and human skin, and their effectiveness was examined using fluorescence microscopy. The results illustrate that this microneedle delivery system is effective in delivering collagen I into the epidermis and dermis of porcine and human skin. Since the technique presented in this paper is quick, safe, effective and easy, it can be considered as a new collagen delivery method for cosmetic and therapeutic applications. PMID:26066056

  13. Vascular smooth muscle cell response on thin films of collagen.

    PubMed

    Elliott, John T; Woodward, John T; Langenbach, Kurt J; Tona, Alex; Jones, Peter L; Plant, Anne L

    2005-10-01

    Vascular smooth muscle cells (vSMC) cultured on gels of fibrillar type I collagen or denatured collagen (gelatin) comprise a model system that has been widely used for studying the role of the extracellular matrix in vascular diseases such as hypertension, restenosis and athrosclerosis. Despite the wide use of this model system, there are several disadvantages to using collagen gels for cellular studies. These include poor optical characteristics for microscopy, difficulty in verifying that the properties of the preparations are identical from experiment to experiment, heterogeneity within the gels, and difficulty in handling the gels because they are fragile. Previously, we developed an alternative collagen matrix by forming thin films of native fibrillar collagen or denatured collagen on self-assembled monolayers of alkanethiols [Elliott, J.T., Tona, A., Woodward, J., Jones,P., Plant, A., 2003a. Thin films of collagen affect smooth muscle cell morphology. Langmuir 19, 1506-1514.]. These substrates are robust and can be characterized by surface analytical techniques that allow both verification of the reproducibility of the preparation and high-resolution analysis of collagen structure. In addition, they have excellent optical properties that allow more details of the cell-matrix interactions to be observed by microscopy. In this study, we performed a side-by-side structural and functional comparison of collagen gels with thin films of collagen. Our results indicate that vSMC on thin films of collagen are nearly identical to vSMC on thick gels as determined by morphology, proliferation rate, integrin ligation, tenascin-C expression and intracellular signaling events. These results suggest that the features of collagen gels that direct the observed vSMC responses are adequately reconstituted in the thin films of collagen. These thin films will be useful for elucidating the features of the collagen matrix that regulate vSMC response and may be applicable to high

  14. 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.

  15. Mechanical Behavior of Collagen-Fibrin Co-Gels Reflects Transition From Series to Parallel Interactions With Increasing Collagen Content

    PubMed Central

    Lai, Victor K.; Lake, Spencer P.; Frey, Christina R.; Tranquillo, Robert T.; Barocas, Victor H.

    2013-01-01

    Fibrin and collagen, biopolymers occurring naturally in the body, are commonly-used biomaterials as scaffolds for tissue engineering. How collagen and fibrin interact to confer macroscopic mechanical properties in collagen-fibrin composite systems remains poorly understood. In this study, we formulated collagen-fibrin co-gels at different collagen-to-fibrin ratios to observe changes in overall mechanical behavior and microstructure. A modeling framework of a two-network system was developed by modifying our micro-scale model, considering two forms of interaction between the networks: (a) two interpenetrating but non-interacting networks (“parallel”), and (b) a single network consisting of randomly alternating collagen and fibrin fibrils (“series”). Mechanical testing of our gels show that collagen-fibrin co-gels exhibit intermediate properties (UTS, strain at failure, tangent modulus) compared to those of pure collagen and fibrin. Comparison with model predictions show that the parallel and series model cases provide upper and lower bounds respectively for the experimental data, suggesting that a combination of such interactions exist between collagen and fibrin in co-gels. A transition from the series model to the parallel model occurs with increasing collagen content, with the series model best describing predominantly fibrin co-gels, and the parallel model best describing predominantly collagen co-gels. PMID:22482659

  16. Definition of the native and denatured type II collagen binding site for fibronectin using a recombinant collagen system.

    PubMed

    An, Bo; Abbonante, Vittorio; Yigit, Sezin; Balduini, Alessandra; Kaplan, David L; Brodsky, Barbara

    2014-02-21

    Interaction of collagen with fibronectin is important for extracellular matrix assembly and regulation of cellular processes. A fibronectin-binding region in collagen was identified using unfolded fragments, but it is not clear if the native protein binds fibronectin with the same primary sequence. A recombinant bacterial collagen is utilized to characterize the sequence requirement for fibronectin binding. Chimeric collagens were generated by inserting the putative fibronectin-binding region from human collagen into the bacterial collagen sequence. Insertion of a sufficient length of human sequence conferred fibronectin affinity. The minimum sequence requirement was identified as a 6-triplet sequence near the unique collagenase cleavage site and was the same in both triple-helix and denatured states. Denaturation of the chimeric collagen increased its affinity for fibronectin, as seen for mammalian collagens. The fibronectin binding recombinant collagen did not contain hydroxyproline, indicating hydroxyproline is not essential for binding. However, its absence may account, in part, for the higher affinity of the native chimeric protein and the lower affinity of the denatured protein compared with type II collagen. Megakaryocytes cultured on chimeric collagen with fibronectin affinity showed improved adhesion and differentiation, suggesting a strategy for generating bioactive materials in biomedical applications.

  17. 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.

  18. 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

  19. 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)

  20. Introduction: Invertebrate Neuropeptides XIII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This publication represents an introduction to the thirteenth in a series of special issues of the Peptides journal dedicated to invertebrate neuropeptides. The issue addresses a number of aspects of invertebrate neuropeptide research including identification of novel invertebrate neuropeptide sequ...

  1. Oxygen Toxicity and Lung Collagenous Protein.

    DTIC Science & Technology

    1981-02-28

    the a and s chains. A large portion of the applied material did not enter the gel until reduced, a behavior typical of this type of sample [20]. The...Collagen. In Crystal RG (ed) The Biochemical Basis of Pulmonary Function, Dekker, New York, pp. 215-271. 11. Hoyer JR, Spiro RG (1978) Studies on the...mono-dispersed lung cell preparations without using time consuming differential gradient centrifugation. Past methods of isolating alveolar type II cells

  2. Effects of Factor XIII Deficiency on Thromboelastography. Thromboelastography with Calcium and Streptokinase Addition is more Sensitive than Solubility Tests

    PubMed Central

    Martinuzzo, M.; Barrera, L.; Altuna, D.; Baña, F. Tisi; Bieti, J.; Amigo, Q.; D’Adamo, M.; López, M.S.; Oyhamburu, J.; Otaso, J.C.

    2016-01-01

    Background Homozygous or double heterozygous factor XIII (FXIII) deficiency is characterized by soft tissue hematomas, intracranial and delayed spontaneous bleeding. Alterations of thromboelastography (TEG) parameters in these patients have been reported. The aim of the study was to show results of TEG, TEG Lysis (Lys 60) induced by subthreshold concentrations of streptokinase (SK), and to compare them to the clot solubility studies results in samples of a 1-year-old girl with homozygous or double heterozygous FXIII deficiency. Case A year one girl with a history of bleeding from the umbilical cord. During her first year of life, several hematomas appeared in soft upper limb tissue after punctures for vaccination and a gluteal hematoma. One additional sample of a heterozygous patient and three samples of acquired FXIII deficiency were also evaluated. Materials and Methods Clotting tests, von Willebrand factor (vWF) antigen and activity, plasma FXIII-A subunit (pFXIII-A) were measured by an immunoturbidimetric assay in a photo-optical coagulometer. Solubility tests were performed with Ca2+-5 M urea and thrombin-2% acetic acid. Basal and post-FXIII concentrate infusion samples were studied. TEG was performed with CaCl2 or CaCl2 + SK (3.2 U/mL) in a Thromboelastograph. Results Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, factor VIIIc, vWF, and platelet aggregation were normal. Antigenic pFXIII-A subunit was < 2%. TEG, evaluated at diagnosis and post FXIII concentrate infusion (pFXIII-A= 37%), presented a normal reaction time (R), 8 min, prolonged k (14 and 11min respectively), a low Maximum-Amplitude (MA) ( 39 and 52 mm respectively), and Clot Lysis (Lys60) slightly increased (23 and 30% respectively). In the sample at diagnosis, clot solubility was abnormal, 50 and 45 min with Ca-Urea and thrombin-acetic acid, respectively, but normal (>16 hours) 1-day post-FXIII infusion. Analysis of FXIII deficient and normal

  3. The protective effects of long-term oral administration of marine collagen hydrolysate from chum salmon on collagen matrix homeostasis in the chronological aged skin of Sprague-Dawley male rats.

    PubMed

    Liang, Jiang; Pei, Xinrong; Zhang, Zhaofeng; Wang, Nan; Wang, Junbo; Li, Yong

    2010-10-01

    To investigate the long-term effects of marine collagen hydrolysate (MCH) from Chum Salmon skin on the aberrant collagen matrix homeostasis in chronological aged skin, Sprague-Dawley male rats of 4-wk-old were orally administrated with MCH at the diet concentrations of 2.25% and 4.5% for 24 mo. Histological and biochemical analysis revealed that MCH had the potential to inhibit the collagen loss and collagen fragmentation in chronological aged skin. Based on immunohistochemistry and western blot analysis, collagen type I and III protein expression levels in MCH-treated groups significantly increased as compared with the aged control group. Furthermore, quantitative real-time polymerase chain reaction and western blot analysis showed MCH was able to increase the expressions of procollagen type I and III mRNA (COL1A2 and COL3A1) through activating Smad signaling pathway with up-regulated TGF-βRII (TβRII) expression level. Meanwhile, MCH was shown to inhibit the age-related increased collagen degradation through attenuating MMP-1 expression and increasing tissue inhibitor of metalloproteinases-1 expression in a dose-dependent manner. Moreover, MCH could alleviate the oxidative stress in chronological aged skin, which was revealed from the data of superoxide dismutase activity and the thiobarbituric acid reactive substances level in skin homogenates. Therefore, MCH was demonstrated to have the protective effects on chronological skin aging due to the influence on collagen matrix homeostasis. And the antioxidative property of MCH might play an important role in the process.

  4. Collagen-Binding Peptidoglycans: A Biomimetic Approach to Modulate Collagen Fibrillogenesis for Tissue Engineering Applications

    PubMed Central

    Paderi, John E.; Sistiabudi, Rizaldi; Ivanisevic, Albena

    2009-01-01

    The small leucine-rich proteoglycans (SLRPs), prevalent in collagenous tissues, regulate collagen fibrillogenesis and provide a host of biochemical cues critical to tissue function and homeostasis. Incorporating SLRPs may enhance tissue engineering designs that mimic the native extracellular matrix, although SLRPs purified from animal sources bear low yields and lack design control. Consequently, we have designed synthetic peptidoglycans, inspired by the native SLRP decorin, that contain a collagen-binding peptide attached to a glycosaminoglycan (GAG) chain. These peptidoglycans modulate collagen fibrillogenesis and decrease fibril diameter in vitro, similarly to decorin, while maintaining the characteristic D-banded fibrils. Application for tissue engineering is demonstrated as these peptidoglycans are incorporated into collagen gels seeded with smooth muscle cells. Gels formed with peptidoglycans and decorin show a faster rate of gel compaction, and one peptidoglycan uniquely increases elastin production. The peptidoglycan design can be tailored with respect to the peptide sequence and GAG identity and is expected to have versatile application in tissue engineering. PMID:19323607

  5. Second Harmonic Light Scattering from Macromolecules: Collagen.

    NASA Astrophysics Data System (ADS)

    Roth, Shmuel

    In this work we present the theory and practice of optical second harmonic generation (SHG) as applied to rat-tail tendon collagen. Our work is the first quantitative application of SHG to biological systems. The angular dependence of SHG is found to display a sharp, intense, forward peak superimposed on a broad background. The sharp peak is shown to imply long-range polar order, while the broad background corresponds to that predicted for the random "up"/"down" array of collagen fibrils seen with the electron microscope. The dependence of fibril diameter distribution on age and state of hydration is measured. Our experiments also reveal information concerning the structure of the fibrils and their arrangement in the tendon. The degree of polar order, the coherence length of tendon for harmonic generation and the absolute magnitude of the nonlinear susceptibility of the collagen fibril are also determined. The biological significance of these findings and the many advantages of SHG for the structural study of biological macromolecules and tissues are discussed.

  6. The collagen triple-helix structure.

    PubMed

    Brodsky, B; Ramshaw, J A

    1997-03-01

    Recent advances, principally through the study of peptide models, have led to an enhanced understanding of the structure and function of the collagen triple helix. In particular, the first crystal structure has clearly shown the highly ordered hydration network critical for stabilizing both the molecular conformation and the interactions between triple helices. The sequence dependent nature of the conformational features is also under active investigation by NMR and other techniques. The triple-helix motif has now been identified in proteins other than collagens, and it has been established as being important in many specific biological interactions as well as being a structural element. The nature of recognition and the degree of specificity for interactions involving triple helices may differ from globular proteins. Triple-helix binding domains consist of linear sequences along the helix, making them amenable to characterization by simple model peptides. The application of structural techniques to such model peptides can serve to clarify the interactions involved in triple-helix recognition and binding and can help explain the varying impact of different structural alterations found in mutant collagens in diseased states.

  7. 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.

  8. Partial characterization of cell-type X collagen interactions.

    PubMed Central

    Luckman, Steven P; Rees, Elaine; Kwan, Alvin P L

    2003-01-01

    Type X collagen is a short-chain non-fibrillar collagen that is deposited exclusively at sites of new bone formation. Although this collagen has been implicated in chondrocyte hypertrophy and endochondral ossification, its precise function remains unclear. One possible function could be to regulate the processes of chondrocyte hypertrophy through direct cell-type X collagen interactions. Adhesions of embryonic chick chondrocytes, and cell lines with known expression of collagen-binding integrins (MG63 and HOS), were assayed on chick type X collagen substrates, including the native, heat-denatured and pepsin-digested collagen, and the isolated C-terminal non-collagenous (NC1) domain. Type X collagen supported the greatest level of adhesion for all cell types tested. The involvement of the alpha2beta1 integrin in type X collagen-cell interaction was demonstrated by adhesion studies in the presence of Mg(2+) and Ca(2+) ions and integrin-function-blocking antibodies. Cells expressing alpha2beta1 integrin (chick chondrocytes and MG63 cells) also adhered to heat-denatured type X collagen and the isolated NC1 domain; however, removal of the non-collagenous domains by limited pepsinization of type X collagen resulted in very low levels of adhesion. Both focal contacts and actin stress-fibre formation were apparent in cells plated on type X collagen. The presence of alpha2 and beta1 integrin subunits in isolated chondrocytes and epiphyseal cartilage was also confirmed by immunolocalization. Our results demonstrate, for the first time, that type X collagen is capable of interacting directly with chondrocytes and other cells, primarily via alpha2beta1 integrin. These findings are atypical from the fibrillar collagen-cell interactions via collagen binding integrins in that: (1) the triple-helical conformation is not strictly required for cell adhesion; (2) the NC1 domain is also involved in the adhesion of alpha2beta1-expressing cells. These data form the basis for further

  9. In situ hybridization reveals that type I and III collagens are produced by pericytes in the anterior pituitary gland of rats.

    PubMed

    Fujiwara, Ken; Jindatip, Depicha; Kikuchi, Motoshi; Yashiro, Takashi

    2010-12-01

    Type I and III collagens widely occur in the rat anterior pituitary gland and are the main components of the extracellular matrix (ECM). Although ECM components possibly play an important role in the function of the anterior pituitary gland, little is known about collagen-producing cells. Type I collagen is a heterotrimer of two α1(I) chains (the product of the col1a1 gene) and one α2(I) chain (the product of the col1a2 gene). Type III collagen is a homotrimer of α1(III) chains (the product of the col3a1 gene). We used in situ hybridization with digoxigenin-labeled cRNA probes to examine the expression of col1a1, col1a2, and col3a1 mRNAs in the pituitary gland of adult rats. mRNA expression for these collagen genes was clearly observed, and cells expressing col1a1, col1a2, and col3a1 mRNA were located around capillaries in the gland. We also investigated the possible double-staining of collagen mRNA and pituitary hormones, S-100 protein (a marker of folliculo-stellate cells), or desmin (a marker of pericytes). Col1a1 and col3a1 mRNA were identified in desmin-immunopositive cells. Thus, only pericytes produce type I and III collagens in the rat anterior pituitary gland.

  10. Energies of peptide peptide and peptide water hydrogen bonds in collagen: Evidences from infrared spectroscopy, quartz piezogravimetry and differential scanning calorimetry

    NASA Astrophysics Data System (ADS)

    Boryskina, O. P.; Bolbukh, T. V.; Semenov, M. A.; Gasan, A. I.; Maleev, V. Ya.

    2007-02-01

    The aim of the present work is a quantitative estimation of energies of peptide-peptide N 1sbnd H 1⋯O 2dbnd C 2 and peptide-water hydrogen bonds in collagen type I and model collagen polypeptide poly(Gly-Pro-Pro). Being a challenging theoretical task this is also an issue that can clarify the physical basis of stability of collagen structures that play a very important structural role in connective tissue. The study was performed on the basis of a complex approach of a number of experimental techniques, namely infrared spectroscopy, quartz piezogravimetry and differential scanning calorimetry. Our results indicate that binding of 3-4 water molecules of the internal hydration shell to each -Gly-X-Y- unit of poly(Gly-Pro-Pro) and collagen leads to simultaneous conformational reorganization of the triple helix and strengthening of the peptide-peptide hydrogen bonds. Enthalpies of hydration of poly(Gly-Pro-Pro) and collagen constitute -10.9 and -12.2 kJ/mol, respectively. Enthalpies of peptide-peptide N 1sbnd H 1⋯O 2dbnd C 2 hydrogen bonds are -7.6 and -6.0 kJ/mol in poly(Gly-Pro-Pro) and collagen, correspondently. The results obtained can be used for evaluation of the impacts of energies of different types of interactions into the total energy of stabilization of native triple helical collagen and poly(Gly-Pro-Pro).

  11. Dynamic variations in the expression of type I collagen and its molecular chaperone Hsp47 in cells of the mouse dental follicle during tooth eruption.

    PubMed

    Shroff, B; Pileggi, R; Norris, K; Orbegoso, R; Wilson, T; Sauk, J J

    1994-03-01

    Tooth eruption is a precisely timed and sequenced event that brings the tooth from within bone into a functional position in the mouth. Every part of the developing tooth has been theoretically implicated as a primary factor in this process, but it now appears that eruption is multifactorial, with the dental follicle and type I collagen playing an important part. Immunological probes were used here to investigate in vivo and in vitro the temporal and spatial expression of type I collagen and its molecular chaperone Hsp47 in the dental follicle during eruption. Mandibles were dissected from 2-, 5-, 9- and 11-day-old neonatal mice and fixed in 95% ethanol overnight. Sections of 7 microns were obtained and reacted with antibodies directed against type I collagen. Dental follicles were isolated from 2-, 5-, 9- and 11-day-old neonates and cells were grown in culture for 8 days. Slides were then reacted with antibodies directed against type I collagen and Hsp47. The production of type I collagen and Hsp47 in the follicle varied with the stage of dental development and eruption. There was a progressive decrease of type I collagen in the coronal part of the follicle, leading to an arrest of its production in these areas. These findings support the notion that cells of the coronal portion of the dental follicle stop producing type I collagen as a prerequisite to the initiation of tooth eruption and that this phenotype persists in vitro.

  12. Characterization of riboflavin-modified dentin collagen matrix.

    PubMed

    Fawzy, A; Nitisusanta, L; Iqbal, K; Daood, U; Beng, L T; Neo, J

    2012-11-01

    Crosslinking is considered a possible approach to increasing the mechanical and structural stability and biodegradation resistance of the dentin collagen matrix. The aim of this study was to investigate the mechanical and chemical variations and collagen degradation resistance associated with crosslinking of the dentin collagen matrix with UVA-activated riboflavin. Dentin collagen matrix specimens were treated with 0.1 and 1% riboflavin for 2 min and photo-activated with 7 mW/cm(2) UVA (368 nm) for 2 min. The structural change of the dentin collagen network with collagenase exposure was investigated by AFM and SEM at different time-points. The variations in surface/bulk mechanical properties and biodegradation resistance were characterized by nano-indentation, conventional mechanical testing, and hydroxyproline liberation at different time-points. Chemical changes associated with riboflavin/collagen-matrix interaction were analyzed by micro-Raman spectroscopy. UVA-activated riboflavin increased the mechanical properties, mechanical stability, and biodegradation resistance of the dentin collagen matrix. Higher collagen-network structural resistance against collagenolytic challenges was found with crosslinking. micro-Raman spectroscopy showed a strong dependency, in both intensity and wave-number, of certain Raman bands (1242-1667 cm(-1)) with crosslinking indicating the collagen/riboflavin interactions. UVA-activated riboflavin (1%) more efficiently crosslinked the dentin collagen matrix within a relatively clinically acceptable time-frame compared with 0.1% riboflavin.

  13. 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.

  14. Collagen Fibril Ultrastructure in Mice Lacking Discoidin Domain Receptor 1.

    PubMed

    Tonniges, Jeffrey R; Albert, Benjamin; Calomeni, Edward P; Roy, Shuvro; Lee, Joan; Mo, Xiaokui; Cole, Susan E; Agarwal, Gunjan

    2016-06-01

    The quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson's trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM.

  15. Collagen Fibril Ultrastructure in Mice Lacking Discoidin Domain Receptor 1

    PubMed Central

    Tonniges, Jeffrey R.; Albert, Benjamin; Calomeni, Edward P.; Roy, Shuvro; Lee, Joan; Mo, Xiaokui; Cole, Susan E.; Agarwal, Gunjan

    2016-01-01

    The quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson’s trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM. PMID:27329311

  16. New Identifications of Fe IX, Fe X, Fe XI, Fe XII, and Fe XIII Lines in the Spectrum of Procyon Observed with the Chandra X-Ray Observatory

    NASA Astrophysics Data System (ADS)

    Beiersdorfer, P.; Lepson, J. K.; Desai, P.; Díaz, F.; Ishikawa, Y.

    2014-02-01

    We have analyzed 280 ks of co-added observations performed with Chandra's Low Energy Transmission Grating Spectrometer using theoretical spectra of Fe VIII through Fe XVII. The model spectral data were produced by combining collisional excitation data generated with the Flexible Atomic Code and transition energies generated with a relativistic code based on the multi-reference Møller-Plesset perturbation theory. The spectroscopic accuracy of the theoretical Fe IX wavelengths was ascertained in a comparison with existing laboratory measurements. We find several new Fe IX lines in the 100-140 Å region and confirm two previous identifications. We also have identified a new line from Fe X near 111 Å several weak features near 102 Å may also be ascribed to Fe X. A line near 100.5 Å is identified as originating from Fe XI; a neighboring feature near 101 Å may also be from Fe XI. A cluster of three weak lines between 117 and 118 Å may be ascribed to Fe XII. Two lines near 104 and 106 Å, respectively, have been assigned to Fe XIII. In addition, we confirmed the presence of two out of four Fe VIII lines that were thought to exist in the spectrum. These two lines are located near 131 Å. The Fe IX emission is weakly sensitive to the assumed electron density, while the Fe XIII is strongly dependent on density. We find that a density between 109 and 1010 cm-3 provides the best fit to the Procyon spectrum. We note that several of the new identifications have come at the expense of prior assignments to magnesium or calcium lines, removing evidence for the presence of these elements in this spectral region. No evidence for Fe XVIII, Fe XIX, or Fe XX was found.

  17. Analysis of cell migration within a three-dimensional collagen matrix.

    PubMed

    Rommerswinkel, Nadine; Niggemann, Bernd; Keil, Silvia; Zänker, Kurt S; Dittmar, Thomas

    2014-10-05

    The ability to migrate is a hallmark of various cell types and plays a crucial role in several physiological processes, including embryonic development, wound healing, and immune responses. However, cell migration is also a key mechanism in cancer enabling these cancer cells to detach from the primary tumor to start metastatic spreading. Within the past years various cell migration assays have been developed to analyze the migratory behavior of different cell types. Because the locomotory behavior of cells markedly differs between a two-dimensional (2D) and three-dimensional (3D) environment it can be assumed that the analysis of the migration of cells that are embedded within a 3D environment would yield in more significant cell migration data. The advantage of the described 3D collagen matrix migration assay is that cells are embedded within a physiological 3D network of collagen fibers representing the major component of the extracellular matrix. Due to time-lapse video microscopy real cell migration is measured allowing the determination of several migration parameters as well as their alterations in response to pro-migratory factors or inhibitors. Various cell types could be analyzed using this technique, including lymphocytes/leukocytes, stem cells, and tumor cells. Likewise, also cell clusters or spheroids could be embedded within the collagen matrix concomitant with analysis of the emigration of single cells from the cell cluster/ spheroid into the collagen lattice. We conclude that the 3D collagen matrix migration assay is a versatile method to analyze the migration of cells within a physiological-like 3D environment.

  18. A novel fibre-ensemble level constitutive model for exogenous cross-linked collagenous tissues

    PubMed Central

    Sacks, Michael S.; Wognum, Silvia

    2016-01-01

    Exogenous cross-linking of soft collagenous tissues is a common method for biomaterial development and medical therapies. To enable improved applications through computational methods, physically realistic constitutive models are required. Yet, despite decades of research, development and clinical use, no such model exists. In this study, we develop the first rigorous full structural model (i.e. explicitly incorporating various features of the collagen fibre architecture) for exogenously cross-linked soft tissues. This was made possible, in-part, with the use of native to cross-linked matched experimental datasets and an extension to the collagenous structural constitutive model so that the uncross-linked collagen fibre responses could be mapped to the cross-linked configuration. This allowed us to separate the effects of cross-linking from kinematic changes induced in the cross-linking process, which in turn allowed the non-fibrous tissue matrix component and the interaction effects to be identified. It was determined that the matrix could be modelled as an isotropic material using a modified Yeoh model. The most novel findings of this study were that: (i) the effective collagen fibre modulus was unaffected by cross-linking and (ii) fibre-ensemble interactions played a large role in stress development, often dominating the total tissue response (depending on the stress component and loading path considered). An important utility of the present model is its ability to separate the effects of exogenous cross-linking on the fibres from changes due to the matrix. Applications of this approach include the utilization in the design of novel chemical treatments to produce specific mechanical responses and the study of fatigue damage in bioprosthetic heart valve biomaterials. PMID:26855761

  19. A novel fibre-ensemble level constitutive model for exogenous cross-linked collagenous tissues.

    PubMed

    Sacks, Michael S; Zhang, Will; Wognum, Silvia

    2016-02-06

    Exogenous cross-linking of soft collagenous tissues is a common method for biomaterial development and medical therapies. To enable improved applications through computational methods, physically realistic constitutive models are required. Yet, despite decades of research, development and clinical use, no such model exists. In this study, we develop the first rigorous full structural model (i.e. explicitly incorporating various features of the collagen fibre architecture) for exogenously cross-linked soft tissues. This was made possible, in-part, with the use of native to cross-linked matched experimental datasets and an extension to the collagenous structural constitutive model so that the uncross-linked collagen fibre responses could be mapped to the cross-linked configuration. This allowed us to separate the effects of cross-linking from kinematic changes induced in the cross-linking process, which in turn allowed the non-fibrous tissue matrix component and the interaction effects to be identified. It was determined that the matrix could be modelled as an isotropic material using a modified Yeoh model. The most novel findings of this study were that: (i) the effective collagen fibre modulus was unaffected by cross-linking and (ii) fibre-ensemble interactions played a large role in stress development, often dominating the total tissue response (depending on the stress component and loading path considered). An important utility of the present model is its ability to separate the effects of exogenous cross-linking on the fibres from changes due to the matrix. Applications of this approach include the utilization in the design of novel chemical treatments to produce specific mechanical responses and the study of fatigue damage in bioprosthetic heart valve biomaterials.

  20. Collagen Structural Hierarchy and Susceptibility to Degradation by Ultraviolet Radiation.

    PubMed

    Rabotyagova, Olena S; Cebe, Peggy; Kaplan, David L

    2008-12-01

    Collagen type I is the most abundant extracellular matrix protein in the human body, providing the basis for tissue structure and directing cellular functions. Collagen has complex structural hierarchy, organized at different length scales, including the characteristic triple helical feature. In the present study, the relationship between collagen structure (native vs. denatured) and sensitivity to UV radiation was assessed, with a focus on changes in primary structure, changes in conformation, microstructure and material properties. A brief review of free radical reactions involved in collagen degradation is also provided as a mechanistic basis for the changes observed in the study. Structural and functional changes in the collagens were related to the initial conformation (native vs. denatured) and the energy of irradiation. These changes were tracked using SDS-PAGE to assess molecular weight, Fourier transform infrared (FTIR) spectroscopy to study changes in the secondary structure, and atomic force microscopy (AFM) to characterize changes in mechanical properties. The results correlate differences in sensitivity to irradiation with initial collagen structural state: collagen in native conformation vs. heat-treated (denatured) collagen. Changes in collagen were found at all levels of the hierarchical structural organization. In general, the native collagen triple helix is most sensitive to UV-254nm radiation. The triple helix delays single chain degradation. The loss of the triple helix in collagen is accompanied by hydrogen abstraction through free radical mechanisms. The results received suggest that the effects of electromagnetic radiation on biologically relevant extracellular matrices (collagen in the present study) are important to assess in the context of the state of collagen structure. The results have implications in tissue remodeling, wound repair and disease progression.

  1. Collagen Structural Hierarchy and Susceptibility to Degradation by Ultraviolet Radiation

    PubMed Central

    Rabotyagova, Olena S.; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    Collagen type I is the most abundant extracellular matrix protein in the human body, providing the basis for tissue structure and directing cellular functions. Collagen has complex structural hierarchy, organized at different length scales, including the characteristic triple helical feature. In the present study, the relationship between collagen structure (native vs. denatured) and sensitivity to UV radiation was assessed, with a focus on changes in primary structure, changes in conformation, microstructure and material properties. A brief review of free radical reactions involved in collagen degradation is also provided as a mechanistic basis for the changes observed in the study. Structural and functional changes in the collagens were related to the initial conformation (native vs. denatured) and the energy of irradiation. These changes were tracked using SDS-PAGE to assess molecular weight, Fourier transform infrared (FTIR) spectroscopy to study changes in the secondary structure, and atomic force microscopy (AFM) to characterize changes in mechanical properties. The results correlate differences in sensitivity to irradiation with initial collagen structural state: collagen in native conformation vs. heat-treated (denatured) collagen. Changes in collagen were found at all levels of the hierarchical structural organization. In general, the native collagen triple helix is most sensitive to UV-254nm radiation. The triple helix delays single chain degradation. The loss of the triple helix in collagen is accompanied by hydrogen abstraction through free radical mechanisms. The results received suggest that the effects of electromagnetic radiation on biologically relevant extracellular matrices (collagen in the present study) are important to assess in the context of the state of collagen structure. The results have implications in tissue remodeling, wound repair and disease progression. PMID:22199459

  2. Heterogeneous nanomechanical properties of type I collagen in longitudinal direction.

    PubMed

    Tang, Ming; Li, Tong; Gandhi, Neha S; Burrage, Kevin; Gu, YuanTong

    2017-01-07

    Collagen is an abundant structural biopolymer in mammal vertebrates, providing structural support as well as mechanical integrity for connective tissues such as bone, ligament, and tendon. The mechanical behaviours of these tissues are determined by the nanomechanics of their structures at different hierarchies and the role of collagen structures in the extracellular matrix. Some studies revealed that there is significant microstructural difference in the longitudinal direction of the collagen fibril, which challenges the conventional rod-like assumption prevalently adopted in the existing studies. Motivated by this discrepancy, in this study, we investigated the longitudinal heterogeneous nanomechanical properties of type I collagen molecule to probe the origin of the longitudinal heterogeneity of the collagen fibril at the molecular level. A full length type I collagen molecule structure was built based on the experimentally calibrated nanostructure. Then, a suitable strain rate was determined for stretching the three intact 'gap' regions and three intact 'overlap' regions of the collagen molecule. Further, the nanomechanical properties of the six collagen molecule segments were characterized by performing steered molecular dynamics simulations, using the obtained suitable strain rate in modelling. The results indicate that this computational model can be used to capture the mechanical behaviour of the collagen molecule under physiological stress conditions. Moreover, the 'gap' regions show a lower stiffness and undergo a slightly lager strain in the unwinding process, compared to the 'overlap' regions of the collagen molecule. This investigation provides insights into the origin of the longitudinal heterogeneity of collagen fibrils at the molecular level and suggests that it is of significant importance to consider the longitudinal heterogeneous mechanical properties of the collagen molecule in the development of coarse-grained models of collagen-related tissues.

  3. Binding of collagens to an enterotoxigenic strain of Escherichia coli

    SciTech Connect

    Visai, L.; Speziale, P.; Bozzini, S. )

    1990-02-01

    An enterotoxigenic strain of Escherichia coli, B34289c, has been shown to bind the N-terminal region of fibronectin with high affinity. We now report that this strain also binds collagen. The binding of 125I-labeled type II collagen to bacteria was time dependent and reversible. Bacteria expressed a limited number of collagen receptors (2.2 x 10(4) per cell) and bound collagen with a Kd of 20 nM. All collagen types tested (I to V) as well as all tested cyanogen bromide-generated peptides (alpha 1(I)CB2, alpha 1(I)CB3, alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB4) were recognized by bacterial receptors, as demonstrated by the ability of these proteins to inhibit the binding of 125I-labeled collagen to bacteria. Of several unlabeled proteins tested in competition experiments, fibronectin and its N-terminal region strongly inhibited binding of the radiolabeled collagen to E. coli cells. Conversely, collagen competed with an 125I-labeled 28-kilodalton fibronectin fragment for bacterial binding. Collagen bound to bacteria could be displaced by excess amounts of either unlabeled fibronectin or its N-terminal fragment. Similarly, collagen could displace 125I-labeled N-terminal peptide of fibronectin bound to the bacterial cell surface. Bacteria grown at 41 degrees C or in the presence of glucose did not express collagen or fibronectin receptors. These results indicate the presence of specific binding sites for collagen on the surface of E. coli cells and furthermore that the collagen and fibronectin binding sites are located in close proximity, possibly on the same structure.

  4. 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.

  5. Behavioral approaches to promoting play.

    PubMed

    Stahmer, Aubyn C; Ingersoll, Brooke; Carter, Cynthia

    2003-12-01

    A variety of techniques grounded in behavioral psychology, and more specifically in applied behavior analysis, have been established to increase and improve play skills in children with autistic spectrum disorders. This article introduces a set of efficacious methods, which range from highly structured techniques to more naturalistic strategies. It focuses on object play as other authors in the issue discuss social play in greater depth. Behavioral techniques that are reviewed include: discrete trial training, use of stereotyped behaviors to increase play skills, pivotal response training, reciprocal imitation training, differential reinforcement of appropriate behavior, in vivo modeling and play scripts, and video modeling. A discussion of expanding behavior techniques to teach more complex play as well as training in varied environments is also presented. References are provided to allow the reader to obtain more in-depth information about each technique.

  6. Let's Play: Teaching Play Skills to Young Children with Autism

    ERIC Educational Resources Information Center

    Boutot, E. Amanda; Guenther, Tracee; Crozier, Shannon

    2005-01-01

    Watch any young child and you will likely see him or her engaged in some form of play. Play is an integral part of early childhood development in which typically developing children learn social and language skills, as well as appropriate behaviors, problem solving, and a variety of other cognitive skills. By its very definition, autism is a…

  7. The Influence of Play Material on Discourse during Play.

    ERIC Educational Resources Information Center

    Burroughs, Elizabeth I.; Murray, Sharon E.

    1992-01-01

    Evaluation of the conversational behavior of 36 children (ages 48-59 months) playing in dyads with 3 different materials (modeling dough, a farm set, and animal puppets) found that each toy elicited the same amount of talking, though there were differences in discourse structure attributable to play materials. (DB)

  8. The Importance of Play: Why Children Need to Play

    ERIC Educational Resources Information Center

    Bodrova, Elena; Leong, Deborah J.

    2005-01-01

    In this article, the authors discuss the important role of dramatic ("pretend") play in early childhood with increasing emphasis at school on developing academic skills in children at younger and younger ages. Play is especially beneficial to children's learning when it reaches a certain degree of sophistication. In other words, "unproductive"…

  9. Playing with the Multiple Intelligences: How Play Helps Them Grow

    ERIC Educational Resources Information Center

    Eberle, Scott G.

    2011-01-01

    Howard Gardner first posited a list of "multiple intelligences" as a liberating alternative to the assumptions underlying traditional IQ testing in his widely read study "Frames of Mind" (1983). Play has appeared only in passing in Gardner's thinking about intelligence, however, even though play instructs and trains the verbal, interpersonal,…

  10. Well Played: The Origins and Future of Playfulness

    ERIC Educational Resources Information Center

    Gordon, Gwen

    2014-01-01

    In this article, the author synthesizes research from several disciplines to shed light on play's central role in healthy development. Gordon builds on research in attachment theory that correlates secure attachment in infancy with adult well-being to demonstrate how playfulness might be a lifelong outcome of secure attachment and a primary…

  11. Type III Collagen Directs Stromal Organization and Limits Metastasis in a Murine Model of Breast Cancer.

    PubMed

    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

    2015-05-01

    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.

  12. Kaempferol suppresses collagen-induced platelet activation by inhibiting NADPH oxidase and protecting SHP-2 from oxidative inactivation.

    PubMed

    Wang, Su Bin; Jang, Ji Yong; Chae, Yun Hee; Min, Ji Hyun; Baek, Jin Young; Kim, Myunghee; Park, Yunjeong; Hwang, Gwi Seo; Ryu, Jae-Sang; Chang, Tong-Shin

    2015-06-01

    Reactive oxygen species (ROS) generated upon collagen stimulation act as second messengers to propagate various platelet-activating events. Among the ROS-generating enzymes, NADPH oxidase (NOX) plays a prominent role in platelet activation. Thus, NOX has been suggested as a novel target for anti-platelet drug development. Although kaempferol has been identified as a NOX inhibitor, the influence of kaempferol on the activation of platelets and the underlying mechanism have never been investigated. Here, we studied the effects of kaempferol on NOX activation, ROS-dependent signaling pathways, and functional responses in collagen-stimulated platelets. Superoxide anion generation stimulated by collagen was significantly inhibited by kaempferol in a concentration-dependent manner. More importantly, kaempferol directly bound p47(phox), a major regulatory subunit of NOX, and significantly inhibited collagen-induced phosphorylation of p47(phox) and NOX activation. In accordance with the inhibition of NOX, ROS-dependent inactivation of SH2 domain-containing protein tyrosine phosphatase-2 (SHP-2) was potently protected by kaempferol. Subsequently, the specific tyrosine phosphorylation of key components (Syk, Vav1, Btk, and PLCγ2) of collagen receptor signaling pathways was suppressed by kaempferol. Kaempferol also attenuated downstream responses, including cytosolic calcium elevation, P-selectin surface exposure, and integrin-αIIbβ3 activation. Ultimately, kaempferol inhibited platelet aggregation and adhesion in response to collagen in vitro and prolonged in vivo thrombotic response in carotid arteries of mice. This study shows that kaempferol impairs collagen-induced platelet activation through inhibition of NOX-derived ROS production and subsequent oxidative inactivation of SHP-2. This effect suggests that kaempferol has therapeutic potential for the prevention and treatment of thrombovascular diseases.

  13. Symbolic play and language development.

    PubMed

    Orr, Edna; Geva, Ronny

    2015-02-01

    Symbolic play and language are known to be highly interrelated, but the developmental process involved in this relationship is not clear. Three hypothetical paths were postulated to explore how play and language drive each other: (1) direct paths, whereby initiation of basic forms in symbolic action or babbling, will be directly related to all later emerging language and motor outputs; (2) an indirect interactive path, whereby basic forms in symbolic action will be associated with more complex forms in symbolic play, as well as with babbling, and babbling mediates the relationship between symbolic play and speech; and (3) a dual path, whereby basic forms in symbolic play will be associated with basic forms of language, and complex forms of symbolic play will be associated with complex forms of language. We micro-coded 288 symbolic vignettes gathered during a yearlong prospective bi-weekly examination (N=14; from 6 to 18 months of age). Results showed that the age of initiation of single-object symbolic play correlates strongly with the age of initiation of later-emerging symbolic and vocal outputs; its frequency at initiation is correlated with frequency at initiation of babbling, later-emerging speech, and multi-object play in initiation. Results support the notion that a single-object play relates to the development of other symbolic forms via a direct relationship and an indirect relationship, rather than a dual-path hypothesis.

  14. 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.

  15. 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.

  16. Specific recognition of the collagen triple helix by chaperone HSP47. II. The HSP47-binding structural motif in collagens and related proteins.

    PubMed

    Koide, Takaki; Nishikawa, Yoshimi; Asada, Shinichi; Yamazaki, Chisato M; Takahara, Yoshifumi; Homma, Daisuke L; Otaka, Akira; Ohtani, Katsuki; Wakamiya, Nobutaka; Nagata, Kazuhiro; Kitagawa, Kouki

    2006-04-21

    The endoplasmic reticulum-resident chaperone heat-shock protein 47 (HSP47) plays an essential role in procollagen biosynthesis. The function of HSP47 relies on its specific interaction with correctly folded triple-helical regions comprised of Gly-Xaa-Yaa repeats, and Arg residues at Yaa positions have been shown to be important for this interaction. The amino acid at the Yaa position (Yaa(-3)) in the N-terminal-adjoining triplet containing the critical Arg (defined as Arg(0)) was also suggested to be directly recognized by HSP47 (Koide, T., Asada, S., Takahara, Y., Nishikawa, Y., Nagata, K., and Kitagawa, K. (2006) J. Biol. Chem. 281, 3432-3438). Based on this finding, we examined the relationship between the structure of Yaa(-3) and HSP47 binding using synthetic collagenous peptides. The results obtained indicated that the structure of Yaa(-3) determined the binding affinity for HSP47. Maximal binding was observed when Yaa(-3) was Thr. Moreover, the required relative spatial arrangement of these key residues in the triple helix was analyzed by taking advantage of heterotrimeric collagen-model peptides, each of which contains one Thr(-3) and one Arg(0). The results revealed that HSP47 recognizes the Yaa(-3) and Arg(0) residues only when they are on the same peptide strand. Taken together, the data obtained led us to define the HSP47-binding structural epitope in the collagen triple helix and also define the HSP47-binding motif in the primary structure. A motif search against human protein database predicted candidate clients for this molecular chaperone. The search result indicated that not all collagen family proteins require the chaperoning by HSP47.

  17. 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.

  18. Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host.

    PubMed

    Singh, Birendra; Fleury, Christophe; Jalalvand, Farshid; Riesbeck, Kristian

    2012-11-01

    Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signalling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s), thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues using various ECM-degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as with the central nervous system or the skin, have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review, we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; retrovirus and papilloma virus.

  19. A method for the quantification of the pressure dependent 3D collagen configuration in the arterial adventitia.

    PubMed

    Schrauwen, J T C; Vilanova, A; Rezakhaniha, R; Stergiopulos, N; van de Vosse, F N; Bovendeerd, P H M

    2012-11-01

    Collagen plays an important role in the response of the arterial wall to mechanical loading and presumably has a load-bearing function preventing overdistension. Collagen configuration is important for understanding this role, in particular in mathematical models of arterial wall mechanics. In this study a new method is presented to image and quantify this configuration. Collagen in the arterial adventitia is stained with CNA35, and imaged in situ at high resolution with confocal microscopy at luminal pressures from 0 to 140mm Hg. The images are processed with a new automatic approach, utilizing techniques intended for MRI-DTI data. Collagen configuration is quantified through three parameters: the waviness, the transmural angle and the helical angle. The method is demonstrated for the case of carotid arteries of the white New Zealand rabbit. The waviness indicated a gradual straightening between 40 and 80mm Hg. The transmural angle was about zero indicating that the fibers stayed within an axial-circumferential plane at all pressures. The helical angle was characterized by a symmetrical distribution around the axial direction, indicating a double symmetrical helix. The method is the first to combine high resolution imaging with a new automatic image processing approach to quantify the 3D configuration of collagen in the adventitia as a function of pressure.

  20. The impact of low levels of collagen IX and pyridinoline on the mechanical properties of in vitro engineered cartilage.

    PubMed

    Yan, Dan; Zhou, Guangdong; Zhou, Xu; Liu, Wei; Zhang, Wen Jie; Luo, Xusong; Zhang, Lu; Jiang, Ting; Cui, Lei; Cao, Yilin

    2009-02-01

    The application of in vitro engineered cartilage has become a promising approach to repair cartilage defects. Nevertheless, the poor mechanical properties of in vitro engineered cartilage limit its potential for clinical applications. Studies have shown that the extracellular matrix (ECM) components are strongly correlated with the mechanical strength of engineered cartilage, but it remains unclear which components play a key role in determining the mechanical property of engineered cartilage. To address this issue, quantitative analyses of cartilage-specific components among native cartilage, in vivo and in vitro engineered cartilages were performed, and the correlation between various ECM molecules and Young's modulus was further analyzed. The results showed that many ECM molecules, such as highly sulphated glycosaminoglycan (GAG), collagens II, IX, and pyridinoline (PYR), contributed to the mechanical strength of cartilages. Further comparison between in vitro engineered cartilage and stress-stimulated in vitro engineered cartilage, known to have stronger mechanical properties, showed that only collagen IX and PYR, but not GAG and collagen II, were the key factors determining the mechanical properties of in vitro engineered cartilage. These results indicate that in vitro environment lacks the niche for enhancing collagen crosslinking that is mediated by collagen IX and PYR during cartilage formation. Thus, the discovery provides a clue for engineering strong cartilage in vitro in the future by enhancing the levels of these two molecules.

  1. Expression of Runx2 and type X collagen in vertebral growth plate of patients with adolescent idiopathic scoliosis.

    PubMed

    Wang, Shoufeng; Qiu, Yong; Ma, Zhaolong; Xia, Caiwei; Zhu, Feng; Zhu, Zezhang

    2010-06-01

    The different expression of type X collagen and Runx2 between the convex and concave side of vertebral growth plate in scoliosis may help to improve our understanding of the role that growth plate tissue play in the development or progression of idiopathic scoliosis. In this investigation, there were significant differences of the total expression of type X collagen, Runx2 protein, and Runx2 mRNA between convex side and concave side growth plates of the apex vertebrae (p < 0.05). The total expression of type X collagen in the concave side growth plates of the lower end vertebrae was higher than that in the same side growth plates of apex (p < 0.05). The total expression of Runx2 in the concave side growth plates in the upper and lower end vertebrae were higher than that in the concave side growth plates of apex (p < 0.05). The expression of type X collagen, Runx2, and Runx2 mRNA, the cell density of type X collagen and Runx2 positive chondrocytes, and histological changes between convex side and concave side of the vertebral growth plate indicated that the vertebral growth plate was affected by mechanical forces, which was a secondary change and could contribute to progression of adolescent idiopathic scoliosis.

  2. 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.

  3. Design and synthesis of collagen mimetic peptide derivatives for studying triple helix assembly and collagen mimetic peptide-collagen binding interaction

    NASA Astrophysics Data System (ADS)

    Mo, Xiao

    2008-10-01

    Collagen is the principal tensile clement of the extra-cellular matrix in mammals and is the basic scaffold for cells and tissues. Collagen molecules are comprised of homo-trimeric helices (e.g. collagen type II and type III), ABB type hetero-trimeric helices (e.g. collagen type I, type IV, and type V), or ABC type hetero-trimeric helices (e.g. type V). Mimicry of collagen structures can help elucidate collagen triple helical conformation and provide insights into making novel collagen-like biomaterials. Our group previously reported a new physical collagen modification method, which was based on non-covalent interaction between collagen mimetic peptide (CMP: -(Pro-Hyp-Gly) x-) and natural collagen. We hypothesized that CMP binds to collagen through a process involving both strand invasion and triple helix assembly. The aim of this dissertation is to study structural formation and stability of collagen triple helix, and to investigate CMP-collagen binding interactions using two types of CMP derivatives: covalently templated CMP trimer and CMP-nanoparticle conjugates. We demonstrated that covalently templated ABB type CMP hetero-trimers could be prepared by a versatile synthetic strategy involving both solid phase and solution peptide coupling. Our thermal melting studies showed that the templated CMP hetero-trimers formed collagen-like triple helices and their folding kinetics correlated with the amino acid compositions of the individual CMP strands. We also studied the thermal melting behavior and folding kinetics of a templated hetero-trimer complex comprised of CMP and a peptide derived from collagen. This synthetic strategy can be readily extended to synthesize other ABB type hetero-trimers to investigate their local melting behavior and biological activity. We also prepared colloidally stable CMP functionalized gold nanoparticles (Au-CMPs) as a TEM marker for investigating the CMP-collagen interaction. Au-CMP showed preferential binding to collagen fiber's gap

  4. Localization of type II collagen, long form alpha 1(IX) collagen, and short form alpha 1(IX) collagen transcripts in the developing chick notochord and axial skeleton.

    PubMed

    Swiderski, R E; Solursh, M

    1992-06-01

    In this study we compare, by in situ hybridization, the spatial and temporal expression patterns of transcripts of avian type II collagen and the long and short forms of the (alpha 1) chain of type IX collagen during the development of the notochord and axial skeleton. We observed type II collagen and short form type IX collagen transcripts in the developing (stage 25-28) nonchondrogenic notochord. Conversely, long form type IX transcripts were not detectable in the notochord or perinotochordal sheath. Interestingly, all three transcripts colocalized in the developing chondrogenic vertebrae of the axial skeleton as well as in the chondrocranium and Meckel's cartilage. The expression of the short form of type IX collagen in these regions was more restricted than that of the long form. This report provides additional support for a complex regulatory pathway of cartilage marker gene expression in chondrogenic vs. nonchondrogenic tissues during avian embryogenesis.

  5. Ventricular remodeling in heart failure: the role of myocardial collagen.

    PubMed

    Janicki, J S; Brower, G L; Henegar, J R; Wang, L

    1995-01-01

    Collagen which is present in the myocardium in relatively small amounts is the most abundant structural protein of the connective tissue network. Its structural organization consists of a complex weave of collagen fibers that surrounds and interconnects myocytes, groups of myocytes, muscle fibers and muscle bundles. The conformation of interstitial fibrillar collagen makes it highly resistant to degradation by all proteinases other than specific collagenases. In hearts with myocardial damage secondary to myocardial infarction, chronic ischemia, inflammation, or cardiomyopathy, a complex sequence of compensatory events occur that eventually result in an adverse left ventricular remodeling. This continual state of remodeling is characterized by persistent collagenase activity, fibrillar collagen degradation, and progressive myocyte loss. The net effect is a shift in the balance between collagen synthesis and degradation which leads to an inadequate fibrillar collagen matrix, progressive ventricular dilatation and sphericalization with wall thinning and eventual congestive heart failure.

  6. Effects of cyclosporin on collagen induced arthritis in mice.

    PubMed Central

    Takagishi, K; Kaibara, N; Hotokebuchi, T; Arita, C; Morinaga, M; Arai, K

    1986-01-01

    We have studied the effect of the immunosuppressive agent cyclosporin on collagen induced arthritis in mice. Cyclosporin, when given prophylactically, was capable of suppressing the development of collagen induced arthritis and the immunological response to native type II collagen in a dose dependent manner. Furthermore, treatment with cyclosporin, started on the same day as the booster injection with type II collagen, also resulted in inhibition of development of arthritis and of immunity to collagen. These findings suggest that the time of a booster injection, three weeks after the initial immunisation, might be still within the induction phase of arthritis since reinoculation is required to produce a high incidence of arthritis in mice. In addition, therapeutic treatment with cyclosporin did not affect the clinical course of the disease or the immune response to collagen. PMID:3754714

  7. 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.

  8. Alternating potentials assisted electrochemical deposition of mineralized collagen coatings.

    PubMed

    Zhuang, Junjun; Lin, Jun; Li, Juan; Weng, Wenjian; Cheng, Kui; Wang, Huiming

    2015-12-01

    Mineralized collagen coatings were synthesized by electrochemical deposition with alternating negative and positive potentials. The obtained coatings demonstrated a multi-layer structure alternating consisting of weakly and highly mineralized collagen layers and the proportion of each layer could be controlled by adjusting the deposition time. The coatings deposited using alternating potentials assisted electrochemical deposition (AP-ECD) showed significantly enhanced osteoblasts proliferation, and rhBMP-2 loading capability compared to those of the coatings deposited using constant potential electrochemical deposition (CP-ECD). The enhanced cytocompatibility and rhBMP-2 loading capability of the coatings might be attributed to their high proportion of weakly mineralized collagen layer. Furthermore, the deposition mechanism for alternating potentials is proposed as that positive potential induces deposition of negatively charged collagen fibrils to form a weakly mineralized collagen layer. Our results suggest that the present deposition method could be a promising approach to engineer mineralized collagen coating with better biological performances.

  9. Young Children and War Play.

    ERIC Educational Resources Information Center

    Carlsson-Paige, Nancy; Levin, Diane E.

    1988-01-01

    In a recent survey of parents and early childhood professionals the prevalence of war play among children and an increase in the amount of violence in children's play was noted. Outlines how the deregulation of children's television during the Reagan administration has affected children's exposure to violence in children's television programming.…

  10. Playing To Get Smart. Viewpoint.

    ERIC Educational Resources Information Center

    Jones, Elizabeth

    2003-01-01

    Asserts that it is through play with materials and relationships, invention of classification systems, and solving problems in dialogue with others that young children develop the basic skills they will need to become effective contributors to the health of a changing world. Offers suggestions for teaching children play skills by providing…

  11. A Place for Block Play.

    ERIC Educational Resources Information Center

    Moore, Gary T.

    1997-01-01

    Discusses the importance of block play--including its contributions to perceptual, fine motor, and cognitive development--and components of a good preschool block play area. Recommends unit blocks complemented by stacking blocks, toys, beads, cubes, and Brio wooden toys. Makes recommendations for space, size, locations and connections to other…

  12. Invention at Play. Educators' Manual.

    ERIC Educational Resources Information Center

    Judd, Michael; Lacasse, Jane; Smith, Monica; Reilly, Katie

    A Smithsonian exhibition was developed that looked at invention in an innovative way. It aimed to encourage visitors to make connections between their own lives and abilities and those of inventors. The role of play in the invention process was examined. Play is a universal and familiar activity and can help people find the link between their own…

  13. Empowering Groups that Enable Play

    ERIC Educational Resources Information Center

    Wilson, David Sloan; Marshall, Danielle; Iserhott, Hindi

    2011-01-01

    Creating play environments for children usually requires groups of adults working together. An extensive scientific literature describes how groups function to achieve shared goals in general terms, and groups attempting to empower play may find this literature useful. Design principles for managing natural resources, identified by Elinor Ostrom…

  14. The Fractal Self at Play

    ERIC Educational Resources Information Center

    Marks-Tarlow, Terry

    2010-01-01

    In this article, the author draws on contemporary science to illuminate the relationship between early play experiences, processes of self-development, and the later emergence of the fractal self. She argues that orientation within social space is a primary function of early play and developmentally a two-step process. With other people and with…

  15. The Social Competence of Play.

    ERIC Educational Resources Information Center

    Fein, Greta G.

    This is a study of how young children gain social competence through pretend play or role playing. Subjects were 38 Caucasian children (19 females, 19 males) who were observed at four ages: 12, 18, 24 and 30 months. The same set of toys, which included a doll, a saucepan, doll bottles, coffee mug, teacup, teaspoon, doll crib, blanket, toy phone…

  16. Sand and Water Table Play

    ERIC Educational Resources Information Center

    Wallace, Ann H.; White, Mary J.; Stone, Ryan

    2010-01-01

    The authors observed preschoolers engaged at the sand and water table to determine if math could be found within their play. Wanting to understand how children interact with provided materials and what kinds of math ideas they explore during these interactions, the authors offer practical examples of how such play can promote mathematical…

  17. Teaching Literature to Adolescents: Plays.

    ERIC Educational Resources Information Center

    Howes, Alan B.

    In this book designed for the high school drama teacher, several commonly-taught plays are used to illustrate (1) ways to use the adolescents' experience with TV to increase their appreciation of other forms of drama, (2) practical means for removing some of the barriers to understanding plays and producing an active response to the world of the…

  18. Engaging Families through Artful Play

    ERIC Educational Resources Information Center

    Brown, Robert

    2015-01-01

    This paper explores how aligned arts and play experiences can extend child and family engagement in a public outdoor space. The importance of outdoor play for children is strongly advocated and in response local governments provide playgrounds and recreational open spaces. To extend further the experiences afforded in such spaces some local…

  19. The Child's Right To Play.

    ERIC Educational Resources Information Center

    Guddemi, Marcy

    Several factors are eroding children's right to play. The first is continuing poverty throughout the world. This factor is evident in underdeveloped countries and the inner cities of industrialized countries. Changing cultural values are a second factor in developed societies where indifference toward the importance of play is prevalent. The many…

  20. Principles of Play for Soccer

    ERIC Educational Resources Information Center

    Ouellette, John

    2004-01-01

    Soccer coaches must understand the principles of play if they want to succeed. The principles of play are the rules of action that support the basic objectives of soccer and the foundation of a soccer coaching strategy. They serve as a set of permanent criteria that coaches can use to evaluate the efforts of their team. In this article, the author…

  1. The Play of Socratic Dialogue

    ERIC Educational Resources Information Center

    Smith, Richard

    2011-01-01

    Proponents of philosophy for children generally see themselves as heirs to the "Socratic" tradition. They often claim too that children's aptitude for play leads them naturally to play with abstract, philosophical ideas. However in Plato's dialogues we find in the mouth of "Socrates" many warnings against philosophising with the young. Those…

  2. Outdoor Play: Combating Sedentary Lifestyles

    ERIC Educational Resources Information Center

    Thigpen, Betsy

    2007-01-01

    Increasingly sedentary lifestyles are contributing to overweight and other health concerns as children spend less and less time outside engaged in active play. Outdoor play provides important opportunities to explore the natural world, interact with peers, engage in vigorous physical activity, and learn about our environment. However, outdoor…

  3. Transmedia Play: Literacy across Media

    ERIC Educational Resources Information Center

    Alper, Meryl; Herr-Stephenson, Rebecca

    2013-01-01

    Transmedia play is a new way to understand how children develop critical media literacy and new media literacies through their interactions with contemporary media that links stories and structures across platforms. This essay highlights five characteristics of transmedia play that make it particularly useful for learning:…

  4. Making Play Work for Education

    ERIC Educational Resources Information Center

    Weisberg, Deena Skolnick; Kittredge, Audrey K.; Hirsh-Pasek, Kathy; Golinkoff, Roberta Michnick; Klahr, David

    2015-01-01

    Children, especially in the preschool years, learn a tremendous amount through play. Research on guided play demonstrates how schools can couple a curriculum-centered preschool program with a developmentally appropriate pedagogical approach to classroom teaching. However, to fully test this claim, we need a clear definition of the term…

  5. Playground Play: Educational and Inclusive

    ERIC Educational Resources Information Center

    Moore, Lisa

    2011-01-01

    It is easy to understand that fun is one of the key ingredients to any playground activity. But what one may not realize is that play systems--including slides, tunnels, activity panels, and more--encourage a lot more than just fun: there is learning at work in playground play, as well as the opportunity to include children of all abilities in…

  6. Preliminary evaluation of collagen as a component in the thermally induced 'weld'

    NASA Astrophysics Data System (ADS)

    Lemole, G. M., Jr.; Anderson, R. Rox; DeCoste, Sue

    1991-06-01

    A simple thermodynamic approach to tissue 'welding' was studied. Fresh bovine tendon (67% type I collagen) was sectioned into disk shaped pieces, pairs of which were inserted between bowed glass coverslips and wrapped in aluminum foil. The packets were heated in a waterbath according to two protocols. In group I, packets were tested for four minutes at temperatures between 55-65 degree(s)C, in 1 degree(s)C intervals. In group II, the packets were kept at 62 degree(s)C for 4 minutes while the rate of cooling was altered. The force necessary to separate the tendon disks was then measured. The optimal temperature for tissue bonding (group I) was 62 degree(s)C (598 gm/in2). Stress values below 250 gm/in2 could be achieved without heat application and were considered non-welds. Group II showed that the faster the sample cools, the stronger the bond. Several conclusions can be postulated. The narrow temperature region necessary for tissue 'welding' strongly suggests that melting of type I collagen fibrils is involved. Bonding presumably occurs at 62 degree(s)C by allowing (alpha) -strands from the collagen super-helix molecule to form new, random connections. Group II results suggest that trans-incisional reannealing of unraveled helices does not play a role in tissue bonding. Rapid cooling allows less time for extended helix reformation; same-side a-helix reannealing may inhibit effective welds by reducing sites for trans-incisional visco-elastic bonding. Although the exact nature and optimization of thermal tissue 'welds' remains unclear, the behavior of collagen appears to play a central role.

  7. The Non-phagocytic Route of Collagen Uptake

    PubMed Central

    Madsen, Daniel H.; Ingvarsen, Signe; Jürgensen, Henrik J.; Melander, Maria C.; Kjøller, Lars; Moyer, Amanda; Honoré, Christian; Madsen, Charlotte A.; Garred, Peter; Burgdorf, Sven; Bugge, Thomas H.; Behrendt, Niels; Engelholm, Lars H.

    2011-01-01

    The degradation of collagens, the most abundant proteins of the extracellular matrix, is involved in numerous physiological and pathological conditions including cancer invasion. An important turnover pathway involves cellular internalization and degradation of large, soluble collagen fragments, generated by initial cleavage of the insoluble collagen fibers. We have previously observed that in primary mouse fibroblasts, this endocytosis of collagen fragments is dependent on the receptor urokinase plasminogen activator receptor-associated protein (uPARAP)/Endo180. Others have identified additional mechanisms of collagen uptake, with different associated receptors, in other cell types. These receptors include β1-integrins, being responsible for collagen phagocytosis, and the mannose receptor. We have now utilized a newly developed monoclonal antibody against uPARAP/Endo180, which down-regulates the receptor protein level on treated cells, to examine the role of uPARAP/Endo180 as a mediator of collagen internalization by a wide range of cultured cell types. With the exception of macrophages, all cells that proved capable of efficient collagen internalization were of mesenchymal origin and all of these utilized uPARAP/Endo180 for their collagen uptake process. Macrophages internalized collagen in a process mediated by the mannose receptor, a protein belonging to the same protein family as uPARAP/Endo180. β1-Integrins were found not to be involved in the endocytosis of soluble collagen, irrespectively of whether this was mediated by uPARAP/Endo180 or the mannose receptor. This further distinguishes these pathways from the phagocytic uptake of particulate collagen. PMID:21652704

  8. 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.

  9. [The use of collagen in the cicatrization of wounds].

    PubMed

    Torra i Bou, J E; Casaroli-Marano, R P; Martínez Cuervo, F; Reina, M; Soldevilla Agreda, J J; Vilaró, S

    2000-10-01

    The authors review the use of collagen in the cicatrization of wounds, analyzing what this process consists of and what its regeneration and reparation phases are. The authors also summarize some fundamental biological aspects collagen has, their functions in hemostasia and in cicatrization; they develop the use of heterologous collagen in the cicatrization process. Expressive illustrations and a selection of bibliographical references accompany this article.

  10. Raman study of the shockwave effect on collagens.

    PubMed

    Cárcamo, José J; Aliaga, Alvaro E; Clavijo, R Ernesto; Brañes, Manuel R; Campos-Vallette, Marcelo M

    2012-02-01

    The Raman spectra (1800-200 cm(-1)) of isolated dried collagen types I and III were recorded at different times after shockwave (SW) application in aqueous media. SWs were applied in a single session. One week after the SW application the vibrational data analysis indicates changes in the conformation of the collagens; orientational changes are also inferred. During the next three weeks collagens tended to recover the conformation and orientation existing before SW application.

  11. Reactions of lipid-derived malondialdehyde with collagen.

    PubMed

    Slatter, D A; Paul, R G; Murray, M; Bailey, A J

    1999-07-09

    Malondialdehyde is a product of fatty acid oxidation (e.g. from low density lipoprotein) implicated in the damage of proteins such as collagen in the cardiovascular system (Chio, K. J., and Tappel, A. L. (1969) Biochemistry 8, 2821-2827). Its concentration is raised in diabetic subjects probably as a side effect of increased protein glycation. Collagen has enzyme-catalyzed cross-links formed between its individual molecules that are essential for maintaining the structure and flexibility of the collagen fiber. The cross-link dehydro-hydroxylysinonorleucine reacts irreversibly with 10 mM malondialdehyde at least 3 orders of magnitude faster than glucose reactions with lysine or arginine, such that there is little cross-link left after 1 h at 37 degrees C. Other cross-links and glycated elements of collagen are also vulnerable. Several possible products of malondialdehyde with collagen cross-links are proposed, and the potential involvement of collagenous histidine in these reactions is discussed. We have also isolated Ndelta-(2-pyrimidyl)-L-ornithine from collagenous arginine reacted with malondialdehyde. The yields of this product were considerably higher than those from model reactions, being approximately 2 molecules/collagen molecule after 1 day at 37 degrees C in 10 mM malondialdehyde. Collagenous lysine-derived malondialdehyde products may have been present but were not protected from protein acid hydrolysis by standard reduction techniques, thus resulting in a multitude of fragmented products.

  12. Fabrication of homobifunctional crosslinker stabilized collagen for biomedical application.

    PubMed

    Lakra, Rachita; Kiran, Manikantan Syamala; Sai, Korrapati Purna

    2015-11-27

    Collagen biopolymer has found widespread application in the field of tissue engineering owing to its excellent tissue compatibility and negligible immunogenicity. Mechanical strength and enzymatic degradation of the collagen necessitates the physical and chemical strength enhancement. One such attempt deals with the understanding of crosslinking behaviour of EGS (ethylene glycol-bis (succinic acid N-hydroxysuccinimide ester)) with collagen to improve the physico-chemical properties. The incorporation of a crosslinker during fibril formation enhanced the thermal and mechanical stability of collagen. EGS crosslinked collagen films exhibited higher denaturation temperature (T d) and the residue left after thermogravimetric analysis was about 16 ± 5.2%. Mechanical properties determined by uniaxial tensile tests showed a threefold increase in tensile strength and Young's modulus at higher concentration (100 μM). Water uptake capacity reduced up to a moderate extent upon crosslinking which is essential for the transport of nutrients to the cells. Cell viability was found to be 100% upon treatment with 100 μM EGS whereas only 30% viability could be observed with glutaraldehyde. Rheological studies of crosslinked collagen showed an increase in shear stress and shear viscosity at 37 °C. Crosslinking with EGS resulted in the formation of a uniform fibrillar network. Trinitrobenzene sulfonate (TNBS) assay confirmed that EGS crosslinked collagen by forming a covalent interaction with ε-amino acids of collagen. The homobifunctional crosslinker used in this study enhanced the effectiveness of collagen as a biomaterial for biomedical application.

  13. Preparation and properties of cellulose nanocrystals reinforced collagen composite films.

    PubMed

    Li, Weichang; Guo, Rui; Lan, Yong; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2014-04-01

    Collagen films have been widely used in the field of biomedical engineering. However, the poor mechanical properties of collagen have limited its application. Here, rod-like cellulose nanocrystals (CNCs) were fabricated and used to reinforce collagen films. A series of collagen/CNCs films were prepared by collagen solution with CNCs suspensions homogeneously dispersed at CNCs: collagen weight ratios of 1, 3, 5, 7, and 10. The morphology of the resulting films was analyzed by scanning electron microscopy (SEM), the enhancement of the thermomechanical properties of the collagen/CNCs composites were demonstrated by thermal gravimetric analysis (TGA) and mechanical testing. Among the CNCs contents used, a loading of 7 wt % led to the maximum mechanical properties for the collagen/CNCs composite films. In addition, in vitro cell culture studies revealed that the CNCs have no negative effect on the cell morphology, viability, and proliferation and possess good biocompatibility. We conclude that the incorporation of CNCs is a simple and promising way to reinforce collagen films without impairing biocompatibility. This study demonstrates that the composite films show good potential for use in the field of skin tissue engineering.

  14. Collagen V nasal tolerance in experimental model of systemic sclerosis.

    PubMed

    Velosa, Ana Paula Pereira; Teodoro, Walcy Rosolia; de Oliveira, Cristiane Carla; Dos Santos Filho, Antonio; Moutinho, Rodnei Francisco; Santos, Angela Gomes; Vendramini, Margarete Borges Galhardo; Bueno, Cleonice; Parra, Edwin Roger; Capelozzi, Vera Luiza; Yoshinari, Natalino Hajime

    2007-07-01

    Our aim was to study skin remodeling and autoantibody production in an experimental model of scleroderma (SSc), following nasal tolerance with human type V collagen (Col V). Female New Zealand rabbits (n = 12) were immunized with two doses of 1 mg/ml of Col V in complete Freund's adjuvant and additional two boosters in incomplete Freund's adjuvant to induce SSc. After 150 days, half of these immunized rabbits were submitted to type V collagen-induced tolerance receiving a daily nasal administration of 25 mug of Col V. Control animals (n = 6) were only submitted to type V collagen-induced tolerance. Serial skin biopsies were performed on days 0, 150 and 210, and stained with H&E, Masson's trichrome and Picrosirius for morphological and morphometric analysis. Types I, III and V collagen were identified by immunofluorescence. The animals' serum samples were collected to determine anti types I, III, IV and V collagen and antinuclear antibodies (ANA). Skin biopsies from immunized animals confirmed SSc morphology as previously described, such as progressive decrease of papillary dermis, appendages atrophy, increased type I, III and V collagen deposition. Rabbits with Col V-induced nasal tolerance showed reduction of skin involvement, with significant decrease of collagen amount. Humoral immune response did not change with nasal tolerance. Collagen V nasal tolerance promotes regression of skin remodeling process in an experimental model of SSc. We suggest that nasal tolerance with type V collagen can be a promising therapeutic option to treat scleroderma patients.

  15. Collagen fibril arrangement and size distribution in monkey oral mucosa

    PubMed Central

    OTTANI, V.; FRANCHI, M.; DE PASQUALE, V.; LEONARDI, L.; MOROCUTTI, M.; RUGGERI, A.

    1998-01-01

    Collagen fibre organisation and fibril size were studied in the buccal gingival and hard palate mucosa of Macacus rhesus monkey. Light and electron microscopy analysis showed connective papillae exhibiting a similar inner structure in the different areas examined, but varying in distribution, shape and size. Moving from the deep to surface layers of the buccal gingival mucosa (free and attached portions), large collagen fibril bundles became smaller and progressively more wavy with decreasing collagen fibril diameter. This gradual diameter decrease did not occur in the hard palate mucosa (free portion, rugae and interrugal regions) where the fibril diameter remained constant. A link between collagen fibril diameter and mechanical function is discussed. PMID:9688498

  16. 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

  17. Playful biometrics: controversial technology through the lens of play.

    PubMed

    Ellerbrok, Ariane

    2011-01-01

    This article considers the role of play in the context of technological emergence and expansion, particularly as it relates to recently emerging surveillance technologies. As a case study, I consider the trajectory of automated face recognition—a biometric technology of numerous applications, from its more controversial manifestations under the rubric of national security to a clearly emerging orientation toward play. This shift toward “playful” biometrics—or from a technology traditionally coded as “hard” to one now increasingly coded as “soft”—is critical insofar as it renders problematic the traditional modes of critique that have, up until this point, challenged the expansion of biometric systems into increasingly ubiquitous realms of everyday life. In response to this dynamic, I propose theorizing the expansion of face recognition specifically in relation to “play,” a step that allows us to broaden the critical space around newly emerging playful biometrics, as well as playful surveillance more generally. In addition, play may also have relevance for theorizing other forms of controversial technology, particularly given its potential role in processes of obfuscation, normalization, and marginalization.

  18. Imaging Prostate Cancer Microenvironment by Collagen Hybridization

    DTIC Science & Technology

    2015-10-01

    bearing a range of selected subcutaneous prostate cancer xenografts resulted in the observation of a trend in which CMP-800 accumulates with higher...xenogratfs to reflect androgen receptor sensitivity status, expression of the biomarker PSMA and speed at which the tumors were growing. Mice bearing ...2. [111In](CXH-A)-(lys2)-DTPA-CMP9-(cys1)-IRDye800CW SPECT-CT at 3-6 h post-injection. Five mice, each bearing a single PC-3 PIP (higher Δ collagen

  19. 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

  20. 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.

  1. Preparation and Biological Activity of New Collagen Composites, Part I: Collagen/Zinc Titanate Nanocomposites.

    PubMed

    Albu, Madalina G; Vladkova, Todorka G; Ivanova, Iliana A; Shalaby, Ahmed S A; Moskova-Doumanova, Veselina S; Staneva, Anna D; Dimitriev, Yanko B; Kostadinova, Anelya S; Topouzova-Hristova, Tanya I

    2016-09-01

    The aim of this investigation was to develop new antimicrobial collagen/zinc titanate (ZnTiO3) biomaterials using a sol-gel cryogenic draying technology in keeping the native collagen activity. Broad-spectrum antimicrobial activity was demonstrated against Firmicutes (Staphylococcus epidermidis, Bacillus cereus, and Candida lusitaniae) and Gracilicutes (Escherichia coli, Salmonella enterica, and Pseudomonas putida) microorganisms. The antimicrobial activity as well as the cytotoxicity were specific for the different test microorganisms (Gram-positive and Gram-negative bacteria and fungi) and model eukaryotic cells (osteosarcoma, fibroblast, and keratinocyte cells), respectively, and both were depending on the ZnTiO3 concentration. Three mechanisms of the antimicrobial action were supposed, including (i) mechanical demolition of the cell wall and membrane by the crystal nanoparticles of the ZnTiO3 entrapped in the collagen matrix, (ii) chelation of its metal ions, and (iii) formation of free oxygen radicals due to the interaction between the microbial cells and antimicrobial agent. It was concluded that the optimal balance between antimicrobial activity and cytotoxicity could be achieved by a variation of the ZnTiO3 concentration. The antifungal and broad-spectrum antibacterial activity of the studied collagen/ZnTiO3 nanocomposites, combined with a low cytotoxicity, makes them a promising anti-infection biomaterial.

  2. Cell Alignment Driven by Mechanically Induced Collagen Fiber Alignment in Collagen/Alginate Coatings

    PubMed Central

    Chaubaroux, Christophe; Perrin-Schmitt, Fabienne; Senger, Bernard; Vidal, Loïc; Voegel, Jean-Claude; Schaaf, Pierre; Haikel, Youssef; Boulmedais, Fouzia; Lavalle, Philippe

    2015-01-01

    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

  3. Lamprey type II collagen and Sox9 reveal an ancient origin of the vertebrate collagenous skeleton.

    PubMed

    Zhang, Guangjun; Miyamoto, Michael M; Cohn, Martin J

    2006-02-28

    Type II collagen is the major cartilage matrix protein in the jawed vertebrate skeleton. Lampreys and hagfishes, by contrast, are thought to have noncollagenous cartilage. This difference in skeletal structure has led to the hypothesis that the vertebrate common ancestor had a noncollagenous skeleton, with type II collagen becoming the predominant cartilage matrix protein after the divergence of jawless fish from the jawed vertebrates approximately 500 million years ago. Here we report that lampreys have two type II collagen (Col2alpha1) genes that are expressed during development of the cartilaginous skeleton. We also demonstrate that the adult lamprey skeleton is rich in Col2alpha1 protein. Furthermore, we have isolated a lamprey orthologue of Sox9, a direct transcriptional regulator of Col2alpha1 in jawed vertebrates, and show that it is coexpressed with both Col2alpha1 genes during skeletal development. These results reveal that the genetic pathway for chondrogenesis in lampreys and gnathostomes is conserved through the activation of cartilage matrix molecules and suggest that a collagenous skeleton evolved surprisingly early in vertebrate evolution.

  4. Adopting the principles of collagen biomineralization for intrafibrillar infiltration of yttria-stabilized zirconia into three-dimensional collagen scaffolds

    PubMed Central

    Zhou, Bin; Niu, Li-na; Shi, Wei; Zhang, Wei; Arola, Dwayne D.; Breschi, Lorenzo; Mao, Jing; Pashley, David H.

    2014-01-01

    In this paper, we report a process for generating collagen-yttria-stabilized amorphous zirconia hybrid scaffolds by introducing acetylacetone-inhibited zirconia precursor nanodroplets into a poly(allylamine)-coated collagen matrix. This polyelectrolyte coating triggers intrafibrillar condensation of the precursors into amorphous zirconia, which is subsequently transformed into tetragonal yttria-stabilized zirconia after calcination. Our findings represent a new paradigm in the synthesis of non-naturally occurring collagen-based hybrid scaffolds under alcoholic mineralizing conditions. PMID:25477773

  5. Nanomechanical Contribution of Collagen and von Willebrand Factor A in Marine Underwater Adhesion and Its Implication for Collagen Manipulation.

    PubMed

    Yoo, Hee Young; Huang, Jun; Li, Lin; Foo, Mathias; Zeng, Hongbo; Hwang, Dong Soo

    2016-03-14

    Recent works on mussel adhesion have identified a load bearing matrix protein (PTMP1) containing von Willebrand factor (vWF) with collagen binding capability that contributes to the mussel holdfast by manipulating mussel collagens. Using a surface forces apparatus, we investigate for the first time, the nanomechanical properties of vWF-collagen interaction using homologous proteins of mussel byssus, PTMP1 and preCollagens (preCols), as collagen. Mimicking conditions similar to mussel byssus secretion (pH < 5.0) and seawater condition (pH 8.0), PTMP1 and preCol interact weakly in the "positioning" phase based on vWF-collagen binding and strengthen in "locked" phase due to the combined effects of electrostatic attraction, metal binding, and mechanical shearing. The progressive enhancement of binding between PTMP1 with porcine collagen under the aforementioned conditions is also observed. The binding mechanisms of PTMP1-preCols provide insights into the molecular interaction of the mammalian collagen system and the development of an artificial extracellular matrix based on collagens.

  6. Microstructural and mechanical differences between digested collagen-fibrin co-gels and pure collagen and fibrin gels.

    PubMed

    Lai, Victor K; Frey, Christina R; Kerandi, Allan M; Lake, Spencer P; Tranquillo, Robert T; Barocas, Victor H

    2012-11-01

    Collagen and fibrin are important extracellular matrix (ECM) components in the body, providing structural integrity to various tissues. These biopolymers are also common scaffolds used in tissue engineering. This study investigated how co-gelation of collagen and fibrin affected the properties of each individual protein network. Collagen-fibrin co-gels were cast and subsequently digested using either plasmin or collagenase; the microstructure and mechanical behavior of the resulting networks were then compared with the respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via three-dimensional network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in co-gels compared with the pure gels. This microstructural change was accompanied by an increased failure strain and decreased tangent modulus for both collagen and fibrin following selective digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated the presence of very long fibers and the clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels.

  7. The pro alpha 2(V) collagen gene is evolutionarily related to the major fibrillar-forming collagens.

    PubMed Central

    Weil, D; Bernard, M; Gargano, S; Ramirez, F

    1987-01-01

    A number of overlapping cDNA clones, covering 5.2 kb of sequences which code for the human pro alpha 2(V) collagen chain, have been isolated. Analysis of the structural data have indicated a close evolutionary kinship between the pro alpha 2(V) chain and the major fibrillar collagen types. Isolation and analysis of an 8 kb genomic fragment has further supported this notion by revealing a homologous arrangement of nine triple-helical domain exons. These studies have therefore provided conclusive evidence which categorizes the Type V collagen as a member of the Group 1 molecules, or fibrillar-forming collagens. Images PMID:3029669

  8. Microstructural and Mechanical Differences Between Digested Collagen-Fibrin Co-Gels and Pure Collagen and Fibrin Gels

    PubMed Central

    Lai, Victor K.; Frey, Christina R.; Kerandi, Allan M.; Lake, Spencer P.; Tranquillo, Robert T.; Barocas, Victor H.

    2012-01-01

    Collagen and fibrin are important extra-cellular matrix (ECM) components in the body, providing structural integrity to various tissues. These biopolymers are also common scaffolds used in tissue engineering. This study investigated how co-gelation of collagen and fibrin affected the properties of each individual protein network. Collagen-fibrin co-gels were cast and subsequently digested using either plasmin or collagenase; the microstructure and mechanical behavior of the resulting networks were then compared with respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via 3-D network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in the co-gels compared to the pure gels; this microstructural change was accompanied by increased failure strain and decreased tangent modulus for both collagen and fibrin following selected digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated presence of very long fibers and clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels. PMID:22828381

  9. 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

  10. Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization.

    PubMed

    Zhang, Zong-Kang; Li, Jie; Yan, De-Xin; Leung, Wing-Nang; Zhang, Bao-Ting

    2016-01-28

    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.

  11. Learning, Play, and Your Newborn

    MedlinePlus

    ... the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding Your 1- to ... Month-Old About the Play & Learn Center Your Child's Development: Newborn Your Child’s Development: 3-5 Days Contact ...

  12. Discussion of "interpretation and play".

    PubMed

    Pick, Irma Brenman

    2011-01-01

    This discussion addresses the conflict in technique between play versus interpretation. It further considers how the nature of the interpretation may be affected by a consideration of what is being projected into the analyst.

  13. A multiverse play divides opinion

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2015-03-01

    The stage lights rise. A man and woman meet in a cute way - "Do you know why it's impossible to lick the tips of your elbows?" she asks - they chat momentarily, and separate. The play is Constellations by Nick Payne.

  14. The Many Faces of Play.

    ERIC Educational Resources Information Center

    Werth, Louise H.

    1984-01-01

    Presents descriptions of play reflecting recent theories, including the psychoanalytic works of Freud, Erikson, and Peller; Piaget's developmental theory (with discussion of Sutton-Smith); and the views of Smilansky and Parten. (AS)

  15. PDGFRα plays a crucial role in connective tissue remodeling.

    PubMed

    Horikawa, Shinjiro; Ishii, Yoko; Hamashima, Takeru; Yamamoto, Seiji; Mori, Hisashi; Fujimori, Toshihiko; Shen, Jie; Inoue, Ran; Nishizono, Hirofumi; Itoh, Hiroshi; Majima, Masataka; Abraham, David; Miyawaki, Toshio; Sasahara, Masakiyo

    2015-12-07

    Platelet derived growth factor (PDGF) plays a pivotal role in the remodeling of connective tissues. Emerging data indicate the distinctive role of PDGF receptor-α (PDGFRα) in this process. In the present study, the Pdgfra gene was systemically inactivated in adult mouse (α-KO mouse), and the role of PDGFRα was examined in the subcutaneously implanted sponge matrices. PDGFRα expressed in the fibroblasts of Pdgfra-preserving control mice (Flox mice), was significantly reduced in the sponges in α-KO mice. Neovascularized areas were largely suppressed in the α-KO mice than in the Flox mice, whereas the other parameters related to the blood vessels and endothelial cells were similar. The deposition of collagen and fibronectin and the expression of collagen 1a1 and 3a1 genes were significantly reduced in α-KO mice. There was a significantly decrease in the number and dividing fibroblasts in the α-KO mice, and those of macrophages were similar between the two genotypes. Hepatocyte growth factor (Hgf) gene expression was suppressed in Pdgfra-inactivated fibroblasts and connective tissue. The findings implicate the role of PDGFRα-dependent ECM and HGF production in fibroblasts that promotes the remodeling of connective tissue and suggest that PDGFRα may be a relevant target to regulate connective tissue remodeling.

  16. Acyclic diterpene glycosides, capsianosides VIII, IX, X, XIII, XV and XVI from the fruits of Paprika Capsicum annuum L. var. grossum BAILEY and Jalapeño Capsicum annuum L. var. annuum.

    PubMed

    Lee, Jong-Hyun; Kiyota, Naoko; Ikeda, Tsuyoshi; Nohara, Toshihiro

    2006-10-01

    Paprika and Jalapeño are used as vegetables and spices. We have obtained six new acyclic diterpene glycosides, called capsianosides XIII (2), XV (3), IX (4), XVI (5), X (6) and VIII (7) together with known capsianoside II (1) from the fruits of the Paprika and Jalapeño. The structures of these compounds have been elucidated by the (1)H- and (13)C-NMR spectra and two-dimensional NMR methods.

  17. Digital Play: A New Classification

    ERIC Educational Resources Information Center

    Marsh, Jackie; Plowman, Lydia; Yamada-Rice, Dylan; Bishop, Julia; Scott, Fiona

    2016-01-01

    This paper draws on an ESRC-funded study of play and creativity in preschool-aged children's use of apps in the UK. The main objectives of the study were to collect information about access to and use of apps in the home, establish the most popular apps and identify the features of those apps that are successful in promoting play and creativity. A…

  18. Periodontal plastic surgery: thermal effect analysis using Erbium:YAG Kesler's handpiece. Histochemical evaluation by Picrosirius red stain and polarization microscopy for collagen determination: in

    NASA Astrophysics Data System (ADS)

    Kesler, Gavriel; Koren, Rumelia; Kesler, Anat; Kristt, Don; Gal, Rivka

    2000-03-01

    Recent technological advances lead to an increase in the options for the treatment of the periodontal diseases. Lasers utilized for gingival soft tissue resurfacing mainly for esthetics purposes, require careful histopathological evaluation of the effects on tissue. Up to date no comparative clinical or histological studies have been performed, aiming at demonstration of the effects of laser irradiation on connective tissue, especially its most important component -- the collagen fibers. The alteration in the structures of this tissue plays the most important role in the healing process. The aim of the present study is to evaluate the influence of Erbium: YAG - Kesler's hand piece on gingival tissue. This handpiece is designed for gingival resurfacing, in cases of 'Gummy smile' and gingival pigmentation. The following irradiation parameters were used: energy per pulse -- 500 mJ, repetition rate 10 pps, spot size 3 mm. Gingival biopsies specimens of 10 patients, 6 with 'Gummy smile' and 4 with gingival pigmentation were examined before laser treatment, and at 7 and 14 days after laser treatment. The tissues were fixed in LNRS, embedded in paraffin, and sectioned into 5 micrometer thickness, dewaxed in xylol and stained with H&E and Picrosirius Red (PSR). The sections were examined by polarization microscopy. PSR is a collagen stain that differentiates collagen fiber density by the range of colors from green through yellow to red, and/or fiber size. This was utilized in the present study to evaluate the hypothesis that Erbium -- YAG (Er: YAG) laser energy is capable of remodeling the collagen fibers in the gingival connective tissue through a photothermal process. We found a significant difference between the structures of collagen fibers at the first week and at 14 days post treatment. In the normal gingiva the predominant polarization colors were in the red-orange range, signifying tightly packed, mature collagen. During the first postoperative week, collagen

  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. Identification of a Collagen Type I Adhesin of Bacteroides fragilis

    PubMed Central

    Galvão, Bruna P. G. V.; Weber, Brandon W.; Rafudeen, Mohamed S.; Ferreira, Eliane O.; Patrick, Sheila; Abratt, Valerie R.

    2014-01-01

    Bacteroides fragilis is an opportunistic pathogen which can cause life threatening infections in humans and animals. The ability to adhere to components of the extracellular matrix, including collagen, is related to bacterial host colonisation. Collagen Far Western analysis of the B. fragilis outer membrane protein (OMP) fraction revealed the presence two collagen adhesin bands of ∼31 and ∼34 kDa. The collagen adhesins in the OMP fraction were separated and isolated by two-dimensional SDS-PAGE and also purified by collagen affinity chromatography. The collagen binding proteins isolated by both these independent methods were subjected to tandem mass spectroscopy for peptide identification and matched to a single hypothetical protein encoded by B. fragilis NCTC 9343 (BF0586), conserved in YCH46 (BF0662) and 638R (BF0633) and which is designated in this study as cbp1 (collagen binding protein). Functionality of the protein was confirmed by targeted insertional mutagenesis of the cbp1 gene in B. fragilis GSH18 which resulted in the specific loss of both the ∼31 kDa and the ∼34 kDa adhesin bands. Purified his-tagged Cbp1, expressed in a B. fragilis wild-type and a glycosylation deficient mutant, confirmed that the cbp1 gene encoded the observed collagen adhesin, and showed that the 34 kDa band represents a glycosylated version of the ∼31 kDa protein. Glycosylation did not appear to be required for binding collagen. This study is the first to report the presence of collagen type I adhesin proteins in B. fragilis and to functionally identify a gene encoding a collagen binding protein. PMID:24618940