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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of fibronectin protein (Fn) coating onto polysaccharide layers of hyaluronic acid (Hyal) and its sulfated derivative (HyalS) on fibroblast cell adhesion was analyzed. The Hyal or HyalS were coated and grafted on the glass substrate by a photolithographic method. The Fn coating was achieved by two different routes: the immobilization of Fn by covalent bond to the polysaccharide layers and the simple adsorption of Fn onto Hyal and HyalS surfaces. AFM, SEM, and ATR-FTIR techniques were used for the chemical and topographical characterization of the surfaces. According to AFM and SEM data, the surface topography was dependent on the method used to cover the polysaccharide layers with the protein. ATR-FTIR analysis supplied information about the rearrangement of Fn after the interaction (adsorption or binding) with the Hyal and the HyalS. The conformational changes of the Fn were minimal when it was simply adsorbed on HyalS surfaces and larger once bound, whereas on the Hyal layer the protein underwent a bigger conformational change once adsorbed and covalently grafted. Then, the biological characterization was carried out by analyzing the human diploid skin fibroblasts adhesion on these surfaces. The morphology of fibroblasts was evaluated by SEM, whereas the dynamics of fibroblasts movement were recorded by a time-lapse system. Cell variations in area, perimeter, and length were analyzed at 2, 4, and 6 h. It was found that the addition of Fn (covalently bound or merely adsorbed) was fundamental in the promotion of fibroblasts adhesion and spreading. The greatest adhesion occurred onto HyalS layers covered by the adsorbed Fn.
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PMID:Fibroblast cell behavior on bound and adsorbed fibronectin onto hyaluronan and sulfated hyaluronan substrates. 1576 24

Gender influences the progression of chronic renal failure (CRF). We studied male (M) and female (F) Wistar rats for 90 days: castrated (CMc,n=7;CFc,n=6) and non castrated controls (CM,n=9;CF,n=6); castrated (CRFMc,n=8; CRFFc,n=6) and non castrated animals submitted to 5/6 nephrectomy (CRFM,n=13;CRFF,n=6). Data are expressed as mean +/-SEM. Proteinuria (PTN) was higher in CRFM (554+/-69 mg/24h) compared to CRFMc (277+/-85 mg/24h), but not in females (CRFF=193+/-20mg/24h, CRFFc= 164+/-71 mg/24h). Mesangial fractional volume increased in all CRF animals. CRF animals showed an increase of glomerular sclerosis index (GSI) and tubulointerstitial damage (TID) but in a smaller proportion in male castrated animals; the opposite occurred with females: castration induced an increase of these parameters. CRF animals showed increased cortical and glomerular fibronectin (FN) rates. Castration decreased glomerular and cortical FN rates in CRFM but not in females. In conclusion, proteinuria was higher in CRFM and probably led to glomerular and interstitial damage, as well as to FN accumulation, castration seems to protect against development of PTN, TID and FN accumulation in males. Castrated female rats presented mesangial expansion, with no changes in PTN, TID and FN rates. It seems that female sex hormones do not protect against renal disease progression, instead, we suggest that male sex hormones lead to acceleration of CRF.
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PMID:Chronic renal failure in male and female rats. 1624 39

Thin films of ZrO2 and hydroxyapatite/ZrO2 were created by excimer laser ablation on Ti6Al4V substrates. ZrO2 layers were fabricated in vacuum by KrF laser at various substrate temperatures and hydroxyapatite (HA) layers were fabricated in water vapor ambient by ArF laser and in water vapor/argon ambient by KrF excimer laser. Film properties were evaluated by XRD, SEM and WDX methods. The test of mechanical adhesion was proceeded on ZrO2 films. XRD analysis proved the presence of amorphous or crystalline HA in the deposited films. SEM method demonstrated smooth surface covered by droplets for both HA and ZrO2 films. Ca/P ratio of the HA films is higher than that of the natural HA and is within the range of 2.8-3.0. The HA/ZrO2 and ZrO2 samples were tested in vitro for cytotoxicity. The best results were received by the HA/ZrO2 samples in the test of cytotoxicity. Fibroblasts cultivating with HA/ZrO2 samples exhibited subconfluent and confluent growth and showed fibronectin homogenously.
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PMID:Study of laser created ZRO2 and hydroxyapatite/ZrO2 films for implantology. 1683 9

This paper describes a novel method for introducing the RGD cell adhesion peptide to enhance cell adhesion onto bacterial cellulose (BC). BC and cotton linters as reference were modified with xyloglucan (XG) and xyloglugan bearing a GRGDS pentapeptide. The adsorptions followed Langmuir adsorption behavior, where both XGs probably decorate the cellulose surfaces as a monolayer. The adsorption maximum of the XGs reached around 180 mg/g on BC and only about three times as much on cotton linters. The adsorption was verified with colorimetric methods. The specific surface area of BC measured with XG and XG-GRGDS was about 200 m (2)/g and was almost three times less for cotton linters, 60 m (2)/g. The difference in the amounts of XGs adsorbed might be explained by the swollen network of bacterial cellulose and a more exposed and accessible bulk as compared to cotton linters. The nanocellulose material was modified homogeneously throughout the material, as seen by the z-scan in confocal microscopy. Moreover, the modification in the water phase, in comparison with organic solvents, was clearly advantageous for preserving the morphology, as observed with SEM. The modification slightly increased the wettability, which might explain the decrease in or undetectable adsorption of adhesive protein shown by QCM-D. Initial cell studies showed that adhesion of human endothelial cells is enhanced when the BC hydrogel is modified with XG-GRGDS. QCM-D studies further revealed that the cell enhancement is due to the presence of the RGD epitope on XG and not to a nonspecific adsorption of fibronectin from cell culture medium. Optimization and proliferation studies of human endothelial cells onto bacterial cellulose modified with XG-GRGDS are currently being carried out at the Vascular Engineering Center, Sahlgrenska University Hospital, Gothenburg.
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PMID:Modification of nanocellulose with a xyloglucan-RGD conjugate enhances adhesion and proliferation of endothelial cells: implications for tissue engineering. 1803 Oct 14

The fabrication of biodegradable 3-D scaffolds enriched with multipotent stem cells seems to be a promising strategy for the repair of irreversibly injured tissues. The fine mechanisms of the interaction of rat mesenchymal stem cells (rMSCs) with a hyaluronan-based scaffold, i.e. HYAFF(R)11, were investigated to evaluate the potential clinical application of this kind of engineered construct. rMSCs were seeded (2 x 10(6) cells cm(-2)) on the scaffold, cultured up to 21 days and analysed using appropriate techniques. Light (LM), scanning (SEM) and transmission (TEM) electron microscopy of untreated scaffold samples showed that scaffolds have a highly porous structure and are composed of 15-microm-thick microfibres having a rough surface. As detected by trypan blue stain, cell adhesion was high at day 1. rMSCs were viable up to 14 days as shown by CFDA assay and proliferated steadily on the scaffold as revealed by MTT assay. LM showed rMSCs in the innermost portions of the scaffold at day 3. SEM revealed a subconfluent cell monolayer covering 40 +/- 10% of the scaffold surface at day 21. TEM of early culture showed rMSCs wrapping individual fibres with regularly spaced focal contacts, whereas confocal microscopy showed polarized expression of CD44 hyaluronan receptor; TEM of 14-day cultures evidenced fibronexus formation. Immunohistochemistry of 21-day cultures showed that fibronectin was the main matrix protein secreted in the extracellular space; decorin and versican were seen in the cell cytoplasm only and type IV collagen was minimally expressed. The expression of CD90, a marker of mesenchymal stemness, was found unaffected at the end of cell culture. Our results show that HYAFF(R)11 scaffolds support the adhesion, migration and proliferation of rMSCs, as well as the synthesis and delivery of extracellular matrix components under static culture conditions without any chemical induction. The high retention rate and viability of the seeded cells as well as their fine modality of interaction with the substrate suggest that such scaffolds could be potentially useful when wide tissue defects are to be repaired as in the case of cartilage repair, wound healing and large vessel replacement.
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PMID:Mesenchymal stem cell interaction with a non-woven hyaluronan-based scaffold suitable for tissue repair. 1901 59

Electrically conducting polypyrrole (PPy) and its composite materials are useful in interfacing electrical components and cells or living tissue. In recent years, significant efforts have been made to bioactivate PPy by incorporating biomolecules. The main objective of this work was to chemically bioactivate PPy particules by incorporating fibronectin (FN) and bovine serum albumin (BSA). Modified PPy particles were synthesized through a water-in-oil emulsion polymerization. XPS and FTIR confirmed the presence of biomolecules on the PPy particles, and the surface morphology was observed by SEM. A four-point probe was used to measure the conductivity of the newly synthesized PPy particles, which was in the range of 10(-1) S cm(-1). Conductive biodegradable membranes were prepared with 5 and 10% (wt/wt) PPy to poly(L,L-lactide) (PPy/PLLA). The contact angles of each synthesized membrane were approximately 75 degrees , supporting their usefulness for cell culture. The cultured human skin fibroblasts demonstrated normal morphology and significantly higher adhesion and spreading on the PPy/PLLA approximately FN membrane than on the unmodified PPy/PLLA membrane. On the other hand, the PPy/PLLA approximately BSA membranes showed decreased cell adhesion. Bioactivated PPy may be useful in tissue engineering to fabricate conducting biodegradable scaffolds with either improved or reduced cell adhesion properties for various cell culture and in vivo applications.
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PMID:Bioactivating electrically conducting polypyrrole with fibronectin and bovine serum albumin. 1917 17

The attachment, growth behaviour and the genetic effect of human gingival fibroblasts (HGF) cultured on titanium and different zirconia surfaces were investigated. HGF cells were cultured on (1) titanium discs with a machined surface, (2) yttrium-stabilized tetragonal zirconia polycrystals (Y-TZP) with a smooth surface and (3) Y-TZP with 100 microm grooves. The cell proliferation activity was evaluated through a MTT assay at 24 h and 48 h, and the cell morphology was examined by SEM. The mRNA expression of integrin-beta1, type I and III collagen, laminin and fibronectin in HGF were evaluated by RT-PCR after 24 h. From the MTT assay, the mean optical density values for the titanium and grooved zirconia surfaces after 48 h of HGF adhesion were greater than the values obtained for the smooth zirconia surfaces. SEM images showed that more cells were attached to the grooves, and the cells appeared to follow the direction of the grooves. The results of RT-PCR suggest that all groups showed comparable fibroblast-specific gene expression. A zirconia ceramic surface with grooves showed biological responses that were comparable to those obtained with HGF on a titanium surface.
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PMID:Attachment and growth behaviour of human gingival fibroblasts on titanium and zirconia ceramic surfaces. 1920 38

To encourage stem cell differentiation, gold nanoparticles (20 nm) were used to deliver electrical stimulation to human embryonic stem cells (hESCs) in vitro. Nano-structured gold nanoparticles were designed by coating the surface of culture dishes with gold nanoparticles using a layer-by-layer (LBL) system. In this method, gold nanoparticles were continuously coated onto dishes by SEM analysis. Evaluation of gene modified hESCs that were subsequently attached onto fibronectin-coated gold nanoparticles revealed that the un-differentiation marker, Oct-4, was no longer present following electrical stimulation. In addition, the osteogenic markers of collagen type I and Cbfa1 increased in response to electrical stimulation, while those of hESCs were not observed without electrical stimulation.
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PMID:The effect of electrical stimulation on the differentiation of hESCs adhered onto fibronectin-coated gold nanoparticles. 1965 37

The objective of this study was to investigate the morphological and immunohistochemical characteristics of vocal fold nodules. The study design was prospective and retrospective. For the histological study, we reviewed 15 slides from the surgical cases of vocal fold nodules, in which we analyzed epithelium, basal membrane (bm), and lamina propria. For the transmission and scanning electron microscopy (TEM, SEM) studies, five new cases on vocal fold nodules were included. Immunohistochemistry study was carried out in the 15 specimens, using antifibronectin, antilaminin, and anticollagen IV antibodies. The main histological alterations were epithelial hyperplasia (73.33%), basement membrane thickening (86.66%), edema, and fibrosis (93.33%). SEM--reduction in mucous lacing and increase in the desquamating cells, without epithelial erosion. TEM--hyperplasia of the epithelium, enlargement of the intercellular junctions, which was filled by fluid, subepithelial thickening of the lamina reticularis, and break points in the basal membrane. Immunohistochemistry--we identified greater immunoexpression of fibronectin on the basal membrane, on the lamina propria, and around the vessels. Antilaminin and anticollagen IV antibodies showed higher pigmentation on the endothelium of the vessels than that on the basal membrane. In vocal fold nodules, combined assessment using light microscopy, electron microscopy, and immunohistochemistry can reveal important morphological details useful in characterizing these lesions.
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PMID:Vocal fold nodules: morphological and immunohistochemical investigations. 1985 10

Endothelial dysfunction or the lack of an endothelium associated with cardiovascular grafts is a major cause of graft failure which is linked to thrombosis and related complications. This study was aimed to (1) biofunctionalise a nanocomposite biomaterial, Polyhedral Oligomeric silsesquioxane modified polycarbonate urea-urethane (POSS-PCU), based small diameter vascular graft and to (2) induce endothelialization with EPC containing monocytes, which were extracted from peripheral blood. (1) Biofunctionalisation of the nanocomposite polymer: bioactive RGD peptide, which is a functional domain of an extracellular matrix component, fibronectin, was synthesised using fmoc chemistry. A lauric acid hydrophobic "tail" was attached to optimise the RGD orientation on the biomaterial. The peptide was cross linked to POSS-PCU. The presence of RGD on the nanocomposite was tested with water contact angle measurements and specificity tests were carried out with the peptide RAD (2) Progenitor cells were extracted from peripheral blood of adult healthy volunteers and cultured on porous biofunctionalised nanocomposite polymer under static conditions. Cells were also introduced to a circuit to which the grafts are connected and non static pulsatile flow conditions were introduced after 72 h following cell introduction. The degree of cell growth was tested with Alamar Blue assay. Endothelialization was confirmed with SEM and by immunostaining for endothelial cell markers, CD34, CD31 and eNOS. Water contact angle measurement indicated that biofunctionalisation had increased hydrophilicity of the nanocomposite polymer. Alamar blue indicated a greater presence of cells on biofunctionalised nanocomposite and this relative increase in cell viability was specific to RGD as confirmed with RAD peptides. SEM provided evidence for endothelial cell morphology and this was confirmed with endothelial cell markers with immunostaining. Biofunctionalised nanocomposite polymer-based small diameter bypass graft demonstrated the potential for relatively rapid endothelialization from cells extracted from peripheral blood.
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PMID:In situ endothelialization potential of a biofunctionalised nanocomposite biomaterial-based small diameter bypass graft. 2004 99


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