bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell‐adhesive thermogelling PNIPAAm/hyaluronic acid cell delivery hydrogels for potential application as minimally invasive retinal therapeutics
Authors: Mazumder M. A. Jafar , Fitzpatrick Scott D. , Muirhead Ben , Sheardown Heather 
Published: April 2012

AbstractCopolymers of N‐isopropylacrylamide (NIPAAm) and acrylic acid N‐hydroxysuccinimide (NAS) were synthesized via free radical polymerization and conjugated with amine‐functionalized hyaluronic acid (HA) and cell adhesive RGDS peptides. These novel copolymers were designed to facilitate noninvasive delivery of a liquid suspension of cells into the delicate subretinal space for treatment of retinal degenerative diseases such as age‐related macular degeneration (AMD) and diabetic retinopathy. The various synthesized copolymers all displayed subphysiological phase transition temperatures, thereby allowing temperature‐induced scaffold formation and subsequent entrapment of transplanted cells within an adhesive support matrix. Successful grafting of HA and RGDS peptides were confirmed with Fourier Transform Infrared (FTIR) spectroscopy and quantified with 1H Nuclear Magnetic Resonance (NMR) spectroscopy. All copolymers demonstrated excellent compatibility with retinal pigment epithelial (RPE) cells in culture and minimal host response was observed following subcutaneous implantation into hairless SKH1‐E mice (strain code 447). © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.
Heparin‐modified dendrimer crosslinked collagen matrices for the delivery of heparin‐binding epidermal growth factor
Authors: Princz M.A. , Sheardown H. 
Published: April 2012

AbstractA tissue engineered corneal equivalent (TECEs) requires host integration to achieve adequate anchorage and long‐term device stability. Corneal integration through epithelialization and stromal integration can be manipulated by growth factors. We investigated the potential of heparin‐binding epidermal growth factor (HB‐EGF) for mediating interactions with human corneal epithelial cells (HCEC) and compared its efficacy to epidermal growth factor (EGF)in vitro. Furthermore, we utilized heparinized dendrimer crosslinked collagen gels, intended for use as TECE, for delivery of HB‐EGF in a sustained manner. HCEC were exposed to HB‐EGF at varying concentrations between 0.1 and 1000 ng/mL. Cell proliferation increased with growth factor concentration up to a concentration of 50 ng/mL, suggesting growth factor receptor down‐regulation at higher HB‐EGF concentrations. Response to HB‐EGF was comparable to EGF at low concentrations of 0.1 and 1 ng/mL but at a concentration of 10 ng/mL, HB‐EGF induced significantly better proliferation than EGF. Proliferation was found to be dependent on the initial seeding density. Heparinized dendrimer crosslinked collagen (CHG) gels were capable of HB‐EGF uptake, which was influenced by heparin concentration within the gel, growth factor concentration and exposure time to the growth factor. HB‐EGF release followed first order kinetics, with ∼90% of the growth factor released after 2 weeks. Growth factor stability was verified within vitroHCEC culture studies. Bioavailability was maintained in the gels through heparin interaction. Overall, HB‐EGF induced proliferation of HCECin vitroand can be released from heparinized collagen gels making it potentially suitable for promoting epithelialization of TECEs. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.
Does the tissue engineering architecture of poly(3‐hydroxybutyrate) scaffold affects cell–material interactions?
Authors: Masaeli Elahe , Morshed Mohammad , Rasekhian Parsa , Karbasi Saeed , Karbalaie Khadije , Karamali Fereshte , Abedi Daryoush , Razavi Shahnaz , Jafarian‐Dehkordi Abbas , Nasr‐Esfahani Mohammad Hossein , Baharvand Hossein 
Published: April 2012

AbstractA critical element in tissue engineering involves the fabrication of a three‐dimensional scaffold. The scaffold provides a space for new tissue formation, supports cellular ingrowth, and proliferation and mimics many roles of the extracellular matrix. Poly(3‐hydroxybutyrate) (PHB) is the most thoroughly investigated member of the polyhydroxyalkanoates (PHAs) family that has various degrees of biocompatibility and biodegradability for tissue engineering applications. In this study, we fabricated PHB scaffolds by utilizing electrospinning and salt‐leaching procedures. The behavior of monkey epithelial kidney cells (Vero) and mouse mesenchymal stem cells (mMSCs) on these scaffolds was compared by the MTS assay and scanning electron microscopy. Additionally, this study investigated the mechanical and physical properties of these scaffolds by measuring tensile strength and modulus, dynamic contact angle and porosity. According to our results, the salt‐leached scaffolds showed more wettability and permeability, but inferior mechanical properties when compared with nanofibrous scaffolds. In terms of cell response, salt‐leached scaffolds showed enhanced Vero cell proliferation, whereas both scaffolds responded similarly in the case of mMSCs proliferation. In brief, nanofibrous scaffolds can be a better substrate for cell attachment and morphology. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.
A novel method to fabricate thermoresponsive microstructures with improved cell attachment/detachment properties
Authors: He Xiao‐Ling , Nie Ping‐Ping , Chen Bi‐Zhou , Li Xiang‐Xu , Chen Li , Guo Gang , Zhang Rui 
Published: April 2012

AbstractA novel, simple, and rapid method to fabricate thermoresponsive micropatterned substrate for cell adhesion, growth, and thermally induced detachment was developed. Thermoresponsive polymer, poly(N‐isopropylacrylamide) (PNIPAAm), was grafted onto the surface of polystyrene (PS) film with microstructure by plasma‐induced graft polymerization technique. The thermoresponsive micropatterned films were characterized by attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy, hydrogen nuclear magnetic resonance (1H NMR) spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). These results indicated that the grafting ratio of PNIPAAm increased with increasing roughness of PS film. However, the microstructures on the substrate were not affected by grafted PNIPAAm. The optimal grafting conditions, such as plasma treatment time, monomer concentration, graft polymerization time, and graft medium were investigated. The thermoresponsive micropatterned films were investigated with the fibroblast cell (L929) adhesion, proliferation, and thermally induced detachment assay. The microstructure on the thermoresponsive micropatterned substrate facilitated cell adhesion above the lower critical solution temperature (LCST) of PNIPAAm and cell detachment below the LCST. Moreover, it can be used to regulate cell organization and tissue growth. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.
Modulation of cellular responses on engineered polyurethane implants
Authors: Khandwekar Anand , Rho Cho K. 
Published: April 2012

AbstractAn in vivo rat cage implant system was used to study the effect of polyurethane surface chemistries on protein adsorption, macrophage adhesion, foreign‐body giant cell formation (FBGCs), cellular apoptosis, and cytokine response. Polyurethanes with zwitterionic, anionic, and cationic chemistries were developed. The changes in the surface topography of the materials were determined using atomic force microscopy and the wettability by dynamic contact angle measurements. The in vitro protein adsorption studies revealed higher protein adsorption on cationic surfaces when compared with the base, while adsorption was significantly reduced on zwitterionic (**p < 0.01) and anionic (*p < 0.05) polyurethanes. Analysis of the exudates surrounding the materials revealed no differences between surfaces in the types or levels of cells present. Conversely, the proportion of adherent cells undergoing apoptosis, as determined by annexin V‐FITC staining, increased significantly on anionic followed by zwitterionic surfaces (60 + 5.0 and 38 + 3.7%) when compared with the base. Additionally, zwitterionic and anionic substrates provided decreased rates of macrophage adhesion and fusion into FBGCs, whereas cationic surfaces promoted macrophage adhesion and FBGC formation. Visualization of the F‐actin cytoskeleton by Alexa Fluor 488 phalloidin showed a significant delay in the cytoskeletal fusion response on zwitterionic and the anionic surfaces. The real‐time polymerase chain reaction (PCR) analysis of proinflammatory cytokines (tumor necrosis factor (TNF)‐α and interleukin (IL)‐10) and pro‐wound healing cytokines (IL‐4 and TGF‐β) revealed differential cytokine responses. Cationic substrates that triggered stimulation of TNF‐α and IL‐4 were associated with more spread cells and higher FBGCs, whereas zwitterionic and anionic substrates that suppressed these cytokines levels were associated with less spread cells and few FBGCs. These studies have revealed that zwitterionic and anionic polyurethane surface chemistries can not only reduce nonspecific adhesion, fusion, and inflammatory events but also effectively promote cellular apoptosis in vivo. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2211–2222, 2012.
Stabilization of collagen tissues by photocrosslinking
Authors: Vashi Aditya V. , Werkmeister Jerome A. , Vuocolo Tony , Elvin Christopher M. , Ramshaw John A. M. 
Published: April 2012

AbstractPhotocrosslinking, using 2 mMRuII(bpy)3Cl2and various concentrations of sodium persulfate with irradiation by blue light, ∼455 nm, has been shown to be a rapid and effective method for crosslinking various tissues: tendon, amnion membrane, pericardium, and heart valve leaflet. The presence of new crosslinking was demonstrated by the increase in the shrinkage temperature of these tissues. In all the cases, increase in the shrinkage temperatures were seen, although at higher sodium persulfate concentrations, for example, 100 mM, both with and without the RuII(bpy)3Cl2catalyst, some degradation of the collagenous tissues was found. The effectiveness of this photocrosslinking method when used with tissues was also shown through the increase in the break strength of tissues after crosslinking, and by the reduction of protein that could be extracted by urea. In solution studies, dityrosine has been shown to be formed during photocrosslinking. With tissues, Western blotting showed the presence of new dityrosine crosslinked proteins. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2239–2243, 2012.
Daily parathyroid hormone 1-34 replacement therapy for hypoparathyroidism induces marked changes in bone turnover and structure
Authors: Gafni Rachel I , Brahim Jaime S , Andreopoulou Panagiota , Bhattacharyya Nisan , Kelly Marilyn H , Brillante Beth A , Reynolds James C , Zhou Hua , Dempster David W , Collins Michael T 
Published: April 2012

Abstract
Parathyroid hormone (PTH) has variable actions on bone. Chronically increased PTH is catabolic and leads to osteoporosis; yet intermittent administration is anabolic and increases bone mass. PTH deficiency is associated with decreased bone remodeling and increased bone mass. However, the effects of PTH replacement therapy on bone in hypoparathyroidism are not well known. We discontinued calcitriol therapy and treated 5 hypoparathyroid subjects (2 adults and 3 adolescents) with synthetic human PTH 1-34 (hPTH 1-34), injected two to three times daily for 18 months, with doses individualized to maintain serum calcium at 1.9 to 2.25 mmol/L. Biochemical markers and bone mineral density (BMD) were assessed every 6 months; iliac-crest biopsies were performed before and after 1 year of treatment. hPTH 1-34 therapy significantly increased bone markers to supranormal levels. Histomorphometry revealed that treatment dramatically increased cancellous bone volume and trabecular number and decreased trabecular separation. Changes in trabecular width were variable, suggesting that the increase in trabecular number was due to the observed intratrabecular tunneling. Cortical width remained unchanged; however, hPTH 1-34 treatment increased cortical porosity. Cancellous bone remodeling was also stimulated, inducing significant changes in osteoid, mineralizing surface, and bone formation rate. Similar changes were seen in endocortical and intracortical remodeling. BMD Z-scores were unchanged at the spine and femoral neck. Total hip Z-scores increased; however, total body BMD Z-scores decreased during the first 6 months of treatment and then stabilized, remaining significantly decreased compared to baseline. Radial Z-scores also decreased with treatment; this was most pronounced in the growing adolescent. Daily hPTH 1-34 therapy for hypoparathyroidism stimulated bone turnover, increased bone volume, and altered bone structure in the iliac crest. These findings suggest that treatment with hPTH 1-34 in hypoparathyroid adults and adolescents has varying effects in the different skeletal compartments, leading to an increase in trabecular bone and an apparent trabecularization of cortical bone. Published 2012 American Society for Bone and Mineral Research. This article is a US Government work and, as such, is in the public domain in the United States of America.
Repression of osteocyte Wnt/β-catenin signaling is an early event in the progression of renal osteodystrophy
Authors: Sabbagh Yves , Graciolli Fabiana Giorgeti , O'Brien Stephen , Tang Wen , dos Reis Luciene Machado , Ryan Susan , Phillips Lucy , Boulanger Joseph , Song Wenping , Bracken Christina , Liu Shiguang , Ledbetter Steven , Dechow Paul , Canziani Maria Eugenia F , Carvalho Aluizio B , Jorgetti Vanda , Moyses Rosa MA , Schiavi Susan C 
Published: April 2012

Abstract
Chronic kidney disease–mineral bone disorder (CKD-MBD) is defined by abnormalities in mineral and hormone metabolism, bone histomorphometric changes, and/or the presence of soft-tissue calcification. Emerging evidence suggests that features of CKD-MBD may occur early in disease progression and are associated with changes in osteocyte function. To identify early changes in bone, we utilized the jck mouse, a genetic model of polycystic kidney disease that exhibits progressive renal disease. At 6 weeks of age, jck mice have normal renal function and no evidence of bone disease but exhibit continual decline in renal function and death by 20 weeks of age, when approximately 40% to 60% of them have vascular calcification. Temporal changes in serum parameters were identified in jck relative to wild-type mice from 6 through 18 weeks of age and were subsequently shown to largely mirror serum changes commonly associated with clinical CKD-MBD. Bone histomorphometry revealed progressive changes associated with increased osteoclast activity and elevated bone formation relative to wild-type mice. To capture the early molecular and cellular events in the progression of CKD-MBD we examined cell-specific pathways associated with bone remodeling at the protein and/or gene expression level. Importantly, a steady increase in the number of cells expressing phosphor-Ser33/37-β-catenin was observed both in mouse and human bones. Overall repression of Wnt/β-catenin signaling within osteocytes occurred in conjunction with increased expression of Wnt antagonists (SOST and sFRP4) and genes associated with osteoclast activity, including receptor activator of NF-κB ligand (RANKL). The resulting increase in the RANKL/osteoprotegerin (OPG) ratio correlated with increased osteoclast activity. In late-stage disease, an apparent repression of genes associated with osteoblast function was observed. These data confirm that jck mice develop progressive biochemical changes in CKD-MBD and suggest that repression of the Wnt/β-catenin pathway is involved in the pathogenesis of renal osteodystrophy. © 2012 American Society for Bone and Mineral Research.
DICAM inhibits osteoclast differentiation through attenuation of the integrin αVβ3 pathway
Authors: Jung Youn-Kwan , Han Seung-Woo , Kim Gun-Woo , Jeong Jae-Hwan , Kim Hyun-Ju , Choi Je-Yong 
Published: April 2012

Abstract
Dual immunoglobulin (Ig) domain-containing adhesion molecule (DICAM) is involved in cell–cell adhesion through a heterophilic interaction with αVβ3 integrin, which suggests that DICAM may participate in osteoclast differentiation. DICAM was localized in the plasma membrane of RAW264.7 and THP-1 cells, and its expression gradually increased during osteoclastogenesis in mouse bone marrow-derived macrophages (BMMs) treated with receptor activator of nuclear factor κ-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Forced expression of DICAM in BMMs and RAW264.7 cells blocked the generation of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts. Conversely, knockdown of DICAM by small hairpin RNA (shRNA) increased osteoclast formation in RAW264.7 cells. DICAM-mediated suppression of osteoclast differentiation was in part due to the inhibition of the p38 mitogen-activated protein (MAP) kinase pathway, which was corroborated by a decrease in the expression of c-Fos and nuclear factor of activated T cells (NFAT)c1. Mechanistically, DICAM directly interacted with integrin β3, which inhibited heterodimerization between integrin αV and β3. Exogenous expression of integrin β3 or high-dose M-CSF rescued DICAM-mediated inhibition of osteoclastogenesis, suggesting crosstalk between the integrin β3 and c-Fms pathways. Finally, recombinant DICAM ectodomain suppressed the RANKL- and M-CSF–induced osteoclastogenesis of BMMs. Collectively, these results indicate that DICAM acts as a negative regulator of osteoclast differentiation by suppressing the integrin αVβ3 pathway. © 2012 American Society for Bone and Mineral Research.
The effect of surface treatments on the microroughness of laser‐sintered and vacuum‐cast base metal alloys for dental prosthetic frameworks
Authors: Castillo‐Oyagüe Raquel , Osorio Raquel , Osorio Estrella , Sánchez‐aguilera Fátima , Toledano Manuel 
Published: April 2012

AbstractThis study aimed to evaluate the effect of four chemomechanical surface treatments on the surface average microroughness and profile of laser‐sintered and vacuum‐cast dental prosthetic structures. Square‐shaped blocks (10 mm × 10 mm × 1.5 mm) were prepared as follows: (1) laser‐sintered CoCr (L) (ST2724G); (2) cast CoCr (C) (Gemium‐cn); and (3) cast NiCrTi (T) (Tilite). Specimens of each alloy group were randomly divided into five subgroups (n = 10 each), depending on the conditioning method used: (1) no treatment (control); (2) sandblasting (125 μm Al2O3‐particles); (3) silica coating (50 μm silica‐modified Al2O3‐particles); (4) oxidation; and (5) oxidation plus opacification. Subgroups 2 and 3 represent “inner” pretreatments proposed for ceramometal restorations to improve the metal surface area available for luting cements. Subgroups 4 and 5 are the “outer” pretreatments required for bonding the aesthetic veneering ceramics to the underlying metal frameworks. Average surface roughness (Ra/μm) was determined using a surface profilometer. Data were analyzed by two‐way ANOVA and Student–Newman–Keuls tests (α = 0.05). Metal surface topography was SEM‐analyzed. Despite the inner pretreatment applied, L samples resulted in the highest microroughness (P < 0.001), whereas sandblasting produced a surface‐smoothing effect in cast specimens. After oxidation, a significant increase in surface roughness occurred in all groups compared with controls, L specimens being the roughest (P < 0.001). Opacification caused a flattening effect of all oxidized structures; all opacified groups resulting in similar microroughness. Laser sintering of CoCr enhances the roughness of metal structures, which may improve the frameworks' microretention of the cements, and of the opaquer before the copings are veneered with the aesthetic ceramics. Microsc. Res. Tech. 75:1206–1212, 2012. © 2012 Wiley Periodicals, Inc.
Morphological observations of ampullae of lorenzini in Squatina guggenheim and S. occulta (chondrichthyes, elasmobranchii, squatinidae)
Authors: Schäfer Bárbara Tavares , Malavasi Carlos Eduardo , Favaron Phelipe Oliveira , Ambrósio Carlos Eduardo , Miglino Maria Angelica , De Amorim Alberto Ferreira , Rici Rose Eli Grassi 
Published: April 2012

AbstractWe have conducted a morphological study of the ampullae of Lorenzini on two shark species from Squatina Genus. In both species, S. guggenheim and S. occulta, the ampullae were observed like small pores scattered in the head region similar to other species of the Chondrichthyes Class. However, differently of the other species a greatest density of ampullae of Lorenzini was observed along of the body surface. After fixation using 10% formaldehyde, the ampullae were removed and processed for light and scanning electron microscopy. Macroscopically, the two shark species differed by the presence of dorsal spines that appeared from the head to the first dorsal fin in S. guggenheim and were absent in S. occulta. Microscopically, there were no differences between the ampullae of Lorenzini channels in these two species. The wall of the ampulla was formed by a simple squamous epithelium. Bands of connective tissue, hyaline cartilage and collagen fibers were found between the ampulla and the skeletal striated muscle layer. Nerve branches responsible for conducting signal pulses to the central nervous system were visible between the muscle and connective tissue layers. Using scanning electron microscopy and histological analysis, we found that the channels were twisted and positioned parallel to the skin. The inside of the channels contained a large amount of a gelatinous secretion composed by polysaccharides. Therefore, we conclude that the morphological combination of extended distribution of the ampullae of Lorenzini and the body shape may represent an adaptation of these species to their way of life. Microsc. Res. Tech. 75:1213–1217, 2012. © 2012 Wiley Periodicals, Inc.
Inhibition by morphine and its analogs of action potentials in adult rat dorsal root ganglion neurons
Authors: Mizuta Kotaro , Fujita Tsugumi , Kumamoto Eiichi 
Published: April 2012

AbstractAlthough opioids inhibit action potential (AP) conduction in primary‐afferent fibers, this has not yet been fully examined. We investigated by using the sharp glass microelectrode technique how opioids (morphine, codeine, and ethylmorphine) affect APs recorded from adult rat dorsal root ganglion (DRG) neurons in response to sciatic nerve stimulation. The DRG neurons were classified into three types, Aα/β, Aδ, and C, according to AP characteristics, including the fiber conduction velocity (CV) of the neuron. AP of the Aα/β neuron was reduced in peak amplitude by each of the opioids in a reversible and concentration‐dependent manner. The potency sequence was ethylmorphine > codeine = morphine (IC50 = 0.70, 2.5, and 2.9 mM, respectively), indicating that this AP inhibition is related to the chemical structure of the opioid. Each of the Aδ and C neuron APs was also inhibited by the opioids; ethylmorphine had a tendency to inhibit APs more effectively than codeine and morphine. This inhibition was variable in extent among neurons and was either comparable to or greater than that of the Aα/β neuron AP. The opioid‐induced AP inhibitions were unaffected by nonspecific opioid‐receptor antagonist naloxone; opioid‐receptor agonists did not affect APs. In conclusion, the opioids inhibited APs in DRG neurons without opioid‐receptor activation; this inhibition was different among neurons having different primary‐afferent fiber CVs and also among the three kinds of opioid. The inhibition by opioid of primary‐afferentfiber AP conduction is suggested to be distinct in extent among fibers conveying distinct types of nociceptive information. © 2012 Wiley Periodicals, Inc.