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QUANTIFICATION OF LEFT VENTRICULAR MYOCARDIAL COLLAGEN SYSTEM IN CHILDREN, YOUNG ADULTS, AND THE ELDERLY

Levy Mendes, Andrea Bogoslavsky; Ferro, Marcelo; Rodrigues, Bruno; De Souza, Monica Rodrigues; Araujo, Rubens Correa; De Souza, Romeu Rodrigues
Fonte: MEDICINA (BUENOS AIRES); BUENOS AIRES Publicador: MEDICINA (BUENOS AIRES); BUENOS AIRES
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.69%
Studies on the collagen system of the human myocardium are still limited compared to those on small laboratory animals. The aim of this work was to observe the collagen tissue of the myocardium of the human heart as a function of age. The types of collagen, as well as the density of collagen tissue and the diameter of collagen fibrils, were examined. Fragments of the left ventricular wall from 15 hearts, 5 from children, 5 from young adults, and 5 from elderly individuals, were analyzed by using the Picrosirius-polarization method and by transmission electron microscopy (TEM). The results showed the presence of collagen type III and collagen type I, both in the endomysium and perimysium of the 3 groups studied. Measurements of collagen content in myocardial tissue displayed that both endomysial and perimysial collagen increase in number and thickness in the adult and elderly. These histochemical results coincided with the observations obtained with the electron microscope in showing an increase in the number of collagen fibrils with a large diameter in the adult and elderly hearts. The present results on cardiac collagen may be important for assessing the pathogenesis of several cardiopathies in the hearts of children, young adults...

Caracterização térmica e reológica de blendas de glicerol:colágeno tipo I de diferentes tecidos; Thermal and rheological characterization of glycerol: type I collagen blends

Egawa, Edgar Yuji
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 20/09/2007 Português
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O colágeno possui características que fazem com seja amplamente utilizado como biomaterial. A termo-estabilidade do colágeno está diretamente relacionada a mudanças na sua estrutura (hélice tripla) via de regra quanto mais estável termicamente uma matriz, mais estável biologicamente será. Vários poliálcoois incluindo o glicerol têm apresentado um aumento na estabilidade térmica do colágeno tipo I, embora o tipo de interação não seja evidente. Este trabalho tem como objetivo estudar o efeito da adição de glicerol sobre o colágeno aniônico obtido por tratamento alcalino (24 H) em três diferentes tecidos: pericárdio e tendão bovinos e serosa porcina. Para isto são utilizados a espectroscopia na região do infravermelho (FTIR), termogravimetria e reologia. Os espectros mostraram que o tratamento alcalino e a adição de glicerol não causam desnaturação da proteína de colágeno. A partir dos resultados das curvas termogravimétricas foi observado que o glicerol aumenta a temperatura de decomposição térmica do colágeno. Os resultados dos ensaios de reologia mais precisamente a varredura de deformação mostrou que as soluções de colágeno apresentam G' maior que G'' independente do tecido de origem, e a adição de glicerol não causa mudanças nesta propriedade das soluções. A varredura de freqüência mostrou que as amostras têm características de um gel...

Remodelamento da pele semelhante à esclerodermia induzido pelo colágeno tipo V; Scleroderma-like remodeling induced by type V collagen

Bezerra, Mailze Campos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 10/05/2007 Português
Relevância na Pesquisa
36.69%
Recentemente, descobrimos que coelhos, Nova Zelândia, imunizados com colágeno tipo V humano mais adjuvante de Freund apresentavam fibrose e vasculite de órgãos normalmente afetados na esclerose sistêmica. Deste modo, nós estudamos o processo de fibrilogênese para identificar possíveis fatores envolvidos na alteração do remodelamento observado neste modelo de esclerodermia. Adicionalmente, fizemos uma comparação preliminar com pele humana obtida de pacientes com esclerodermia (n=3). Coelhos fêmeas, Nova Zelândia (n=14), foram imunizados subcutaneamente com duas doses de 1mg de colágeno V mais adjuvante completo de Freund, com intervalo de 30 dias, seguido de duas imunizações em adjuvante incompleto de Freund, via intramuscular, com intervalo de 15 dias. Os animais do grupo controle (n- 14) foram inoculados somente com adjuvante completo e incompleto de Freund, nas mesmas condições dos imunizados. Foram realizadas análises histológicas das peles dos animais e pacientes através da coloração com tricrômico de Masson e imunofluorescêcia, a fim de detectar fibras de colágeno e interação dos colágenos I, III e V. A análise da pele dos animais demonstrou depósito precoce de fibras de colágeno na derme após 7 dias da sensibilização...

Análises dos efeitos do colágeno bovino e derivados na proliferação celular e biossíntese de colágeno em fibroblastos humanos.; Analysis of bovine collagen and derivates effects in the cell proliferation and collagen biosyntesis in human fibroblasts.

Rodrigues, Vergimari
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/03/2009 Português
Relevância na Pesquisa
36.73%
O colágeno é a proteína fibrosa predominante da matriz extracelular e é a maior proteína constituinte do tecido conectivo. Alterações nas taxas de colágeno tipo I na derme ocorrem durante o envelhecimento. A introdução de um agente eficaz para a manutenção da pele durante o envelhecimento é importante, possibilitando a redução destes efeitos. Neste projeto foram avaliados os efeitos proliferativos e de biossíntese de colágeno, em fibroblastos humanos de derme normal tratados com colágeno bovino e derivados de diferentes perfis moleculares, colágeno super hidrolisado, colágeno hidrolisado e gelatina, em diferentes experimentos, adesão e viabilidade celular, síntese de colágeno e análises das fases do ciclo celular. Os resultados sugerem que o colágeno bovino e derivados induzem as propriedades adesivas nos fibroblastos, não desencadeiam efeitos citotóxicos e induzem a biossíntese de colágeno pelos fibroblastos. Os resultados de síntese de colágeno indicam que concentrações menores de colágeno super hidrolisado e colágeno hidrolisado podem ser utilizadas em relação à amostra de gelatina. Comparando os resultados após 48 horas de cultura na síntese de colágeno e nas modificações na fase S do ciclo celular...

Estudo da participação do colágeno V no câncer de pulmão, especificamente no carcinoma não de pequenas células; Study of the involvement of collagen V in lung cancer specifically in non-small cell carcinoma

Souza, Paola da Costa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/09/2011 Português
Relevância na Pesquisa
36.7%
O colágeno V vem emergindo como um potente indutor de morte celular (apoptose) via caspase. Nosso objetivo, neste estudo, foi examinar a interface entre o colágeno dos tipos I, III e V, apoptose tumoral e endotelial, angiogênese e células imunes, assim como o impacto desses fatores no prognóstico de pacientes com carcinomas não de pequenas células (CNPC) de pulmão. As amostras foram obtidas de 65 pacientes com CNPC de pulmão cirurgicamente excisados. Foram utilizados imunofluorescência e histomorfometria para colágenos I, III e V; imunohistoquímica e histomorfometria para avaliar apoptose endotelial e epitelial pelas caspases 5, 6, 8, 9 e via TUNEL, antiapoptose pela expressão do Bcl-2 e Bcl-6, densidade microvascular utilizando CD34, atividade vascular através da endotelina, VCAM e CD54, além da laminina. As células imunes foram imunomarcadas pelo CD3, CD4, CD8, CD20, CD56 Cd1a, S100, CD68 e as seguintes citocinas foram quantificadas: IL-4, IL-6, IL-8 e TGF-. O modelo de sobrevida de Cox mostrou que, quando controlados pelo estadiamento patológico linfonodal N, somente o colágeno do tipo V e a apoptose endotelial via caspase-9 foram significativamente associados com a sobrevida. Uma medida de corte ao nível da mediana para o colágeno do tipo V e caspase-9 dividiu os pacientes em dois grupos distintos de prognóstico. Aqueles com colágeno V maior do que 9...

Collagen-hydroxyapatite films: piezoelectric properties

Silva, C. C.; Thomazini, D.; Pinheiro, A. G.; Aranha, N.; Figueiro, S. D.; Goes, J. C.; Sombra, A. S. B.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 210-218
Português
Relevância na Pesquisa
36.73%
In this paper we report a study of the physicochemical, dielectric and piezoelectric properties of anionic collagen and collagen-hydroxyapatite (HA) composites, considering the development of new biomaterials which have potential applications in support for cellular growth and in systems for bone regeneration. The piezoelectric strain tensor element d(14), the elastic constant s(55) and the dielectric permittivity 8(11), were measured for the anionic collagen and collagen-HA films. The thermal analysis shows that the denaturation endotherm is at 59.47 degreesC for the collagen sample. The collagen-HA composite film shows two transitions, at 48.9 and 80.65 degreesC. The X-ray diffraction pattern of the collagen film shows a broad band characteristic of an amorphous material. The main peaks associated to the crystalline HA is present in the sample of collagen-HA. In the collagen-HA composite, one can also notice the presence of other peaks with low intensities which is an indication of the formation of other crystalline phases of apatite. The scanning electron photomicrograph of anionic collagen membranes shows very thin bundles of collagen. The scanning electron photomicrography of collagen-HA film also show deposits of hydroxyapatite on the collagen fibers forming larger bundles and suggesting that a collagenous structure of reconstituted collagen fibers could act as nucleators for the formation of apatite crystal similar to those of bone. The piezoelectric strain tensor element d(14) was measured for the anionic collagen...

The importance of size-exclusion characteristics of type I collagen in bonding to dentin matrices

Takahashi, M.; Nakajima, M.; Tagami, J.; Scheffel, D. L S; Carvalho, R. M.; Mazzoni, A.; Cadenaro, M.; Tezvergil-Mutluay, A.; Breschi, L.; Tjäderhane, L.; Jang, S. S.; Tay, F. R.; Agee, K. A.; Pashley, D. H.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.7%
The mineral phase of dentin is located primarily within collagen fibrils. During development, bone or dentin collagen fibrils are formed first and then water within the fibril is replaced with apatite crystallites. Mineralized collagen contains very little water. During dentin bonding, acid-etching of mineralized dentin solubilizes the mineral crystallites and replaces them with water. During the infiltration phase of dentin bonding, adhesive comonomers are supposed to replace all of the collagen water with adhesive monomers that are then polymerized into copolymers. The authors of a recently published review suggested that dental monomers were too large to enter and displace water from collagen fibrils. If that were true, the endogenous proteases bound to dentin collagen could be responsible for unimpeded collagen degradation that is responsible for the poor durability of resin-dentin bonds. The current work studied the size-exclusion characteristics of dentin collagen, using a gel-filtration-like column chromatography technique, using dentin powder instead of Sephadex. The elution volumes of test molecules, including adhesive monomers, revealed that adhesive monomers smaller than ∼1000 Da can freely diffuse into collagen water...

Emulsões estabilizadas por colageno : efeito da hidrolise termica e do processo de homogeneização; Emulsions stabilized by collagen : effect of thermal hydrolysis and emulsification process

Rejane de Castro Santana
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 03/09/2009 Português
Relevância na Pesquisa
36.73%
O colágeno é uma proteína de origem animal de grande disponibilidade no Brasil e com aplicações nas indústrias de alimentos, farmacêutica e cosmética na forma de gelatina. Com o intuito de entender e melhorar as propriedades emulsificantes de ingredientes à base de colágeno extraído do couro bovino, as propriedades físico-químicas da fibra de colágeno foram inicialmente avaliadas e modificadas através da hidrólise parcial em temperaturas de 50 à 85°C por períodos de 20 e 60 minutos. O processo de hidrólise aumentou a solubilidade do colágeno de 2,9 % (m/m) para 33,0 % (m/m) e produziu frações de menor massa molar, que chegaram a alcançar 37 kDa no hidrolisado a 85°C/60min. A temperatura de desnaturação do colágeno encontrou-se em torno de 64°C, sendo que os tratamentos a 65°C e 85°C foram capazes de desnaturar totalmente a fibra de colágeno. Já as propriedades emulsificantes do colágeno foram avaliadas através da estabilidade, microestrutura e reologia de emulsões simples óleo/água (O/A) estabilizadas por colágeno, verificando a influência do pH, tipo de ingrediente (pó e fibra de colágeno), concentração de proteína, hidrólise térmica do colágeno, conteúdo de proteína solúvel e processo de homogeneização. A estabilidade estérica e eletrostática das macro-emulsões aumentou com a concentração de proteína e com a redução do pH...

Características do colágeno, textura e cor da carne (músculos Longissimus, Semitendinosus, Supraspinatus e Infraspinatus) de fêmeas bovinas adultas de quatro grupos genéticos; Characteristics of collagen, texture and color (muscles Longissimus, Semitendinosus, Supraspinatus and Infraspinatus) fof mature female of four genetics groups

Edsom Roberto Lorenci Toneto
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/02/2012 Português
Relevância na Pesquisa
36.73%
A genética, a maturidade e as variações entre músculos podem influir sobre a qualidade da carne. A avançada idade ao abate de fêmeas da subespécie Bos indicus, que constitue a grande maioria do rebanho, tem determinado a oferta de carnes menos macias para os consumidores brasileiros. A maciez é o principal atributo de qualidade da carne e o aspecto mais considerado pelo consumidor na hora da compra. A proteólise miofibrilar devido ao sistema enzimático calpaínas - calpastatina tem sido apontada como o principal mecanismo envolvido no amaciamento da carne post mortem. Entretanto, o conteúdo, a solubilidade e a estabilidade térmica do colágeno presente na musculatura também podem influir na maciez. O objetivo desta pesquisa foi avaliar o efeito das características do colágeno (conteúdo, solubilidade e estabilidade térmica) textura e cor sobre a qualidade da carne de vacas contemporâneas, sendo 19 ½ Angus x ½ Nelore, 16 ½ Canchim x ½ Nelore, 13 ½ Simental x ½ Nelore e 15 da raça Nelore com idade média de 10 anos provenientes do CPPSE da Embrapa de São Carlos, SP e abatidas em frigorífico comercial. Foram realizadas análises de pH, perda por cocção, força de cisalhamento, comprimento de sarcômero, quantidade...

Estudo da formação de fosfatos de calcio pela mineralização de matrizes de colageno; Study of calcium phosphate precipitation by mineralization of collagen

Lauter Jose Marques Allegretti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/02/2009 Português
Relevância na Pesquisa
36.7%
A matriz óssea é um nanocompósito formado basicamente de fosfato de cálcio (70% m) e colágeno (30% m), responsável pela resistência mecânica dos ossos, e, portanto, pela função mais importante do esqueleto. A perda de qualidade de vida que pode ser causada por enfermidades e traumas dos ossos aumenta a importância em estudar e compreender este material fantástico. O crescimento da expectativa de vida da população torna mais comum os problemas com os ossos. Desta forma, entendermos as características e propriedades dos ossos, ou seja, conhecê-las melhor, pode contribuir para a solução destes problemas. Neste trabalho nos propusemos a estudar a influência de matrizes de colágeno tipo I no processo de mineralização de fosfato de cálcio no interior delas. Pela permeação de vapor de amônia em soluções de colágeno em pH 2 contendo íons Ca e H2PO4, foram obtidos géis de colágeno que foram estruturados, simultaneamente com a formação de fosfato de cálcio em seu interior. Além do colágeno estruturado, sob condições especiais, foram obtidas fibras (fibrilogênese) de colágeno, mineralizadas pela precipitação de fosfato de cálcio. Para avaliar a influência de uma matriz de colágeno anisotrópica sobre a organização das partículas de fosfato de cálcio...

Marine origin collagen membranes for drug delivery

Marques, A. P.; Domingues, A.; Silva, Joana M.; Perez-Martin, R. I.; Sotelo, C. G.; Silva, Tiago H.; Reis, R. L.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em /06/2014 Português
Relevância na Pesquisa
36.74%
Introduction: Collagen is the most abundant protein of animal connective tissues, found in skins, bones or cartilages, which turn it into one of the key polymers to be considered for biomedical applications, namely tissue engineering and drug delivery. Current industrial procedures to extract collagen involves bovine and porcine as main sources. However, due to religious factors and the risk of transmitting diseases to humans, the search for new sources has been growing.Marine origin is one of the alternatives that has been explored, particularly, through by-products of fish processing, such as skins, scales or spines, with both economic and environmental benefits [1]. In this work, collagen was extracted from shark Scyliorhinus canicula skin. The collagen was processed and further evaluated as alternative for dermal membranes, regarding sustained release of drugs. Materials and methods: Extraction of collagen: Skins of shark (Scyliorhinus canicula) were treated with 0.1 M NaHO to remove non-collagenous proteins, cleaned with distilled water and then collagen was extracted with 0.5 M acetic acid, overnight. After centrifugation, the supernatant was purified by dialysis and the resultant collagen solution was freeze-dried. The produced collagen was characterized by FTIR...

Effect of an aqueous extract of Phaseolus vulgaris on the properties of tail tendon collagen of rats with streptozotocin-induced diabetes

Pari,L.; Venkateswaran,S.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2003 Português
Relevância na Pesquisa
36.73%
Changes in the structural and functional properties of collagen caused by advanced glycation might be of importance for the etiology of late complications in diabetes. The present study was undertaken to investigate the influence of oral administration of aqueous pod extract (200 mg/kg body weight) of Phaseolus vulgaris, an indigenous plant used in Ayurvedic Medicine in India, on collagen content and characteristics in the tail tendon of streptozotocin-diabetic rats. In diabetic rats, collagen content (117.01 ± 6.84 mg/100 mg tissue) as well as its degree of cross-linking was increased, as shown by increased extent of glycation (21.70 ± 0.90 µg glucose/mg collagen), collagen-linked fluorescence (52.8 ± 3.0 AU/µmol hydroxyproline), shrinkage temperature (71.50 ± 2.50ºC) and decreased acid (1.878 ± 0.062 mg hydroxyproline/100 mg tissue) and pepsin solubility (1.77 ± 0.080 mg hydroxyproline/100 mg tissue). The alpha/ß ratio of acid- (1.69) and pepsin-soluble (2.00) collagen was significantly decreased in streptozotocin-diabetic rats. Administration of P. vulgaris for 45 days to streptozotocin-diabetic rats significantly reduced the accumulation and cross-linking of collagen. The effect of P. vulgaris was compared with that of glibenclamide...

Supraorganized collagen enhances Schwann cell reactivity and organization in vitro

Maturana,L.G.; Zanon,R.G.; Pierucci,A.; Vidal,B.C.; Oliveira,A.L.R.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2011 Português
Relevância na Pesquisa
36.72%
We investigated the reactivity and expression of basal lamina collagen by Schwann cells (SCs) cultivated on a supraorganized bovine-derived collagen substrate. SC cultures were obtained from sciatic nerves of neonatal Sprague-Dawley rats and seeded on 24-well culture plates containing collagen substrate. The homogeneity of the cultures was evaluated with an SC marker antibody (anti-S-100). After 1 week, the cultures were fixed and processed for immunocytochemistry by using antibodies against type IV collagen, S-100 and p75NTR (pan neurotrophin receptor) and for scanning electron microscopy (SEM). Positive labeling with antibodies to the cited molecules was observed, indicating that the collagen substrate stimulates SC alignment and adhesion (collagen IV labeling - organized collagen substrate: 706.33 ± 370.86, non-organized collagen substrate: 744.00 ± 262.09; S-100 labeling - organized collagen: 3809.00 ± 120.28, non-organized collagen: 3026.00 ± 144.63, P < 0.05) and reactivity (p75NTR labeling - organized collagen: 2156.33 ± 561.78, non-organized collagen: 1424.00 ± 405.90, P < 0.05; means ± standard error of the mean in absorbance units). Cell alignment and adhesion to the substrate were confirmed by SEM analysis. The present results indicate that the collagen substrate with an aligned suprastructure...

Type 1 collagen influence on gene expression in UMR106-06 osteoblast-like cells is inhibited by genistein

Celic, S.; Katayama, Y.; Chilco, P.; Martin, T.; Findlay, D.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Artigo de Revista Científica
Publicado em //1998 Português
Relevância na Pesquisa
36.72%
We have previously shown that an exogenous type I collagen matrix can regulate expression of mRNA for parathyroid hormone (PTH)-related protein (PTHrP) and its receptor, the PTH/PTHrP receptor, in the UMR106-06 osteogenic sarcoma cell line, which is considered to be representative of a relatively mature osteoblast phenotype. Consistent with those data, we show here that growth of UMR106-06 cells on type I collagen increased PTH/PTHrP receptor-binding capacity. Analysis of the binding data showed that the number of PTH/PTHrP receptors expressed by cells cultured on collagen was at least 2-fold greater than that of cells cultured on plastic. Expression of mRNA encoding alkaline phosphatase (ALP) and osteopontin (OP) was also upregulated in cells cultured on collagen, suggesting that interaction with collagen promotes the osteoblast phenotype in this cell line. Retinoic acid (RA), which has also been shown to promote osteoblastic differentiation, synergized with type I collagen to cause super-induction of OP mRNA. In contrast, RA abolished the collagen-induced increase in ALP mRNA and PTH/PTHrP receptor mRNA. The collagen-mediated increase in the expression of OP and PTH/PTHrP receptor mRNA, but not that of ALP, was perturbed by prior covalent modification of the collagen by non-enzymatic glycation. The collagen effects did not occur via interaction with RGD amino acid domains in type I collagen...

beta ig-h3 interacts directly with biglycan and decorin, promotes collagen VI aggregation, and participates in ternary complexing with these macromolecules

Reinboth, B.; Thomas, J.; Hanssen, E.; Gibson, M.
Fonte: Amer Soc Biochemistry Molecular Biology Inc Publicador: Amer Soc Biochemistry Molecular Biology Inc
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
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36.72%
Recombinant human βig-h3 was found to bind 125I-labeled small leucine-rich proteoglycans (SLRPs), biglycan, and decorin, in co-immunoprecipitation experiments. In each instance the binding could be blocked by an excess of the unlabeled proteoglycan, confirming the specificity of the interaction. Scatchard analysis showed that biglycan bound βig-h3 more avidly than decorin with Kd values estimated as 5.88 x 10–8 and 1.02 x 10–7 M, respectively. In reciprocal blocking experiments both proteoglycans inhibited the others binding to βig-h3 indicating that they may share the same binding site or that the two binding sites are in close proximity on the βig-h3 molecule. Since βig-h3 and the SLRPs are known to be associated with the amino-terminal region of collagen VI in tissue microfibrils, the effects of including collagen VI in the incubations were investigated. Co-immunoprecipitation of 125I-labeled biglycan incubated with equimolar mixtures of βig-h3 and pepsin-collagen VI was increased 6-fold over βig-h3 alone and 3-fold over collagen VI alone. Similar increases were also observed for decorin. The findings indicate that βig-h3 participates in a ternary complex with collagen VI and SLRPs. Static light scattering techniques were used to show that βig-h3 rapidly forms very high molecular weight complexes with both native and pepsin-collagen VI...

Evaluation der Wertigkeit des Kollagen IV als Prädiktor einer glomerulären Erkrankung; Evaluation of urinary type IV collagen as a marker of glomerular structural damage in various clinical settings

Zotzmann, Viviane
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
36.7%
Einleitung: Kollagen Typ IV ist einer der Hauptbestandteile der glomerulären Basalmembran. Strukturelle Veränderungen der Basalmembran lassen sich bei fibrosierenden Nierenerkrankungen früher als funktionelle Veränderungen nachweisen. Bei Patienten mit diabetischer Nephropathie konnten erhöhte Kollagen IV-Spiegel im Urin gemessen werden bevor eine Mikroalbuminurie auftrat. Die Urin-Kollagen IV-Ausscheidung gilt somit als frühzeitiger Marker für glomeruläre Schäden. In der vorliegenden Studie sollte geprüft werden, ob die Urin-Kollagen IV-Bestimmung eine sinnvolle klinische Methode zum Nachweis einer glomerulären Schädigung bei Patienten mit unterschiedlichen Nierenerkrankungen darstellt. Methoden: In Urinproben von 195 Patienten und gesunden Kontrollpersonen wurden Urin-Kollagen IV-Spiegel, Kreatinin-Clearance, Albumin und Eiweiß sowie die Serum-Kreatinin-Konzentration gemessen. Es wurden Patienten mit bioptisch gesicherten Glomerulonephritiden, arterieller Hypertonie, diabetischer Nephropathie und einer Nierenbeteiligung bei Sepsis untersucht. Die Urin-Kollagen IV-Spiegel wurden mittels eines quantitativen Enzyme-Immuno-Assay (EIA) bestimmt. Ergebnisse: Die Urin-Kollagen Typ IV-Ausscheidung ist signifikant erhöht bei Patienten mit schwerer Infektion...

Design of Heterotrimeric Collagen Triple Helices

Jalan, Abhishek
Fonte: Universidade Rice Publicador: Universidade Rice
Português
Relevância na Pesquisa
36.73%
Select loci in native collagen display clusters of contiguous amino acids that recognize a diverse array of extracellular matrix (ECM) and blood serum proteins critical for homeostasis and hemostasis. The mechanism of collagen binding to these proteins has primarily been elucidated using short peptides, called collagen mimetic peptides (CMPs), that independently fold into the so called homotrimeric collagen triple helices, where all three peptide chains have identical amino acid sequence. However, the homotrimer binding mechanism cannot be extrapolated to explain protein binding in AAB and ABC-type heterotrimeric collagens that contain either two or three unique polypeptide chains without significant speculation. Given the requirement of a one amino acid offset between the peptide chains in a collagen triple helix, a mixture of two or three unique peptides can self-assemble into 8 and 27 competing triple helices, respectively. Heterotrimeric CMPs have remained synthetically inaccessible due to the challenge associated with introducing bias in this ensemble of competing states. Previously, Hartgerink lab employed axial Lys – Asp / Glu salt-bridges to successfully self-assemble an ABC heterotrimer. Here, we extend this paradigm to successfully demonstrate the design of a proof-of-principle AAB heterotrimer. Four AAB heterotrimers...

Multi-Hierarchical Self-Assembly of Collagen Mimetic Peptides into AAB Type Heterotrimers, Nanofibers and Hydrogels Driven by Charged Pair Interactions

O'Leary, Lesley Russell
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Thesis; Text Formato: 258 p.; application/pdf
Português
Relevância na Pesquisa
36.69%
Replicating the multi-hierarchical self-assembly of collagen (peptide chain to triple helix to nanofiber and, finally, to a hydrogel) has long attracted scientists, both from the fundamental science perspective of supramolecular chemistry and for the potential biomedical applications perceived in tissue engineering. In terms of triple helical formation, collagen is the most abundant protein in the human body with at least 28 types, yet research involving collagen mimetic systems has only recently began to consider the innate ability of collagen to control helix composition and register. Collagen triple helices can be homotrimeric or heterotrimeric and while some types of natural collagen form only one specific composition of helix, others can form multiple. It is critical to fully understand and, if possible, reproduce the control that native collagen has on helix composition and register. In terms of nanofiber formation, many approaches to drive the self-assembly of synthetic systems through the same steps as natural collagen have been partially successful, but none have simultaneously demonstrated all levels of structural assembly. In this work, advancements in the ability to control helix composition and replicate the multi-hierarchical assembly of collagen are described. Both positive and negative design for the assembly of AAB type collagen heterotrimers were utilized by promoting heterotrimer formation though the use of charged amino acids to form intra-helix electrostatic interactions...

Collagen V-induced nasal tolerance downregulates pulmonary collagen mRNA gene and TGF-beta expression in experimental systemic sclerosis

VELOSA, Ana Paula P.; TEODORO, Walcy R.; ANJOS, Daniel M. dos; KONNO, Renata; OLIVEIRA, Cristiane C.; KATAYAMA, Maria L. H.; PARRA, Edwin R.; CAPELOZZI, Vera L.; YOSHINARI, Natalino H.
Fonte: BIOMED CENTRAL LTD; LONDON Publicador: BIOMED CENTRAL LTD; LONDON
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.72%
Background: The purpose of this study was to evaluate collagen deposition, mRNA collagen synthesis and TGFbeta expression in the lung tissue in an experimental model of scleroderma after collagen V-induced nasal tolerance. Methods: Female New Zealand rabbits (N = 12) were immunized with 1 mg/ml of collagen V in Freund's adjuvant (IM). After 150 days, six immunized animals were tolerated by nasal administration of collagen V ( 25 mu g/day) (IM-TOL) daily for 60 days. The collagen content was determined by morphometry, and mRNA expressions of types I, III and V collagen were determined by Real-time PCR. The TGF-beta expression was evaluated by immunostaining and quantified by point counting methods. To statistic analysis ANOVA with Bonferroni test were employed for multiple comparison when appropriate and the level of significance was determined to be p < 0.05. Results: IM-TOL, when compared to IM, showed significant reduction in total collagen content around the vessels (0.371 +/- 0.118 vs. 0.874 +/- 0.282, p < 0.001), bronchioles (0.294 +/- 0.139 vs. 0.646 +/- 0.172, p < 0.001) and in the septal interstitium (0.027 +/- 0.014 vs. 0.067 +/- 0.039, p = 0.026). The lung tissue of IM-TOL, when compared to IM, showed decreased immunostaining of types I...

Optimisation of UV Irradiation as a Binding Site Conserving Method for Crosslinking Collagen-based Scaffolds

Davidenko, Natalia; Bax, Daniel B.; Schuster, Carlos F.; Farndale, Richard W.; Hamaia, Samir W.; Best, Serena M.; Cameron, Ruth E.
Fonte: Springer Publicador: Springer
Tipo: Article; accepted version
Português
Relevância na Pesquisa
36.7%
This is the author accepted manuscript. It is currently embargoed pending publication.; Short wavelength (?=254nm) UV irradiation was evaluated over a range of intensities (0.06 to 0.96 J/cm2) as a means of cross-linking collagen- and gelatin-based scaffolds, to tailor their material characteristics whilst retaining biological functionality. Zero-link carbodiimide treatments are commonly applied to collagen-based materials, forming cross-links from carboxylate anions (for example the acidic E of GFOGER) that are an essential part of integrin binding sites on collagen. Cross-linking these amino acids therefore disrupts the bioactivity of collagen. In contrast, UV irradiation forms bonds from less important aromatic tyrosine and phenylalanine residues. We therefore hypothesised that UV cross-linking would not compromise collagen cell reactivity. Here, highly porous (~99%) isotropic, collagen-based scaffolds were produced via ice-templating. A series of scaffolds (pore diameters ranging from 130-260?m) with ascending stability in water was made from gelatin, two different sources of collagen I, or blends of these materials. Glucose, known to aid UV crosslinking of collagen, was added to some lower-stability formulations. These scaffolds were exposed to different doses of UV irradiation...