bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of varying Al2O3 percentage in hydroxyapatite/Al2O3 composite materials: Morphological, chemical and cytotoxic evaluation
Authors: Epure L.M. , Dimitrievska S. , Merhi Y. , Yahia L.'H. 
Published: June 2007

AbstractHydroxyapatite (HA) and HA‐alumina (HA/Al2O3) composites, with Al2O3 contents of 5, 10, 20, and 30%, were synthesized using a wet precipitation method and sintered at 900 and 1300°C. We investigated the effect of sintering temperature and relative concentration of HA and Al2O3 on the chemical composition, surface morphology, and cytotoxicity of the composite powders. The XRD results show that in the 1300°C composites, HA partially decomposed into CaO which combined with Al2O3 to form different calcium aluminates. For the 900°C composites the CaO phase was not detected, though a Ca/P ratio larger than 1.67 measured by XPS suggests that CaO was present in trace amounts. SEM‐EDX analysis indicated that the HA microstructure was affected by the sintering temperature, and this HA is present on the surface of Al2O3 particles. The cytotoxicity of the composites was assessed indirectly using the MTT assay. The short‐term effect of leachables was quantified by exposing a L929 mouse fibroblast cell line to the degradation products released by the composites after immersion in the cell culture medium. Degradation products were less toxic to L‐929 at lower extract concentrations (10, 50%) than at 100% concentration. Cell viability was also influenced by leachable size. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Poly(glycerol sebacate) supports the proliferation and phenotypic protein expression of primary baboon vascular cells
Authors: Gao Jin , Ensley Ann E. , Nerem Robert M. , Wang Yadong 
Published: June 2007

AbstractPoly(glycerol sebacate) (PGS) is a biodegradable and biocompatible elastomer specifically developed for soft tissue engineering. Vascular cells adhered to an elastomer may exhibit more physiological behavior because the substrate's mechanical properties more closely match those of the tissue. To investigate the feasibility of using PGS as a scaffold material for vascular tissue engineering, the authors examined the adhesion, proliferation, and phenotypic and morphologic properties of primary baboon endothelial progenitor cells (BaEPCs) and baboon smooth muscle cells (BaSMCs) cultured on PGS films and scaffolds. Tissue culture‐treated polystyrene plates were used as controls. Phase contrast microscopy indicated that both types of cells showed normal morphology on PGS films. Immuofluorescent staining revealed that von Willebrand factor and α‐smooth muscle actin were expressed by BaEPCs and BaSMCs, respectively. Both types of cells proliferated well on PGS surfaces. When cultured in PGS scaffolds, BaSMCs were distributed throughout the scaffolds and synthesized extracellular matrix, as indicated by histological evaluations. The distribution of the BaSMCs in the constructs was confirmed by scanning electron microscopy. Immunofluorescent staining of cocultured constructs indicated that the BaSMC‐seeded constructs provided suitable surfaces for BaEPC adhesion, and both types of cells maintained their specific phenotypes. These results suggest that PGS is an appropriate scaffold material for blood vessel tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Diffusion of camptothecin immobilized with cationic surfactant into agarose hydrogel containing anionic carrageenan
Authors: Liu Jianhong , Li Lin 
Published: June 2007

AbstractCamptothecin (CPT) is a hydrophobic antitumor drug. Controlled release of CPT from hydrogel has not been satisfactorily achieved because of its poor compatibility and weak interaction with a hydrophilic hydrogel matrix. A new approach has been attempted in this work to solve these problems. In our approach, CPT was first solubilized in a micellar solution of cetyltrimethylammonium bromide (CTAB), a cationic surfactant. It was found that the solubility of CPT could be enhanced by CTAB (10 mM) to 0.17 mg/mL, which is 127 times higher than that in pure water, providing a great feasibility of drug loading. The micellar drug solution of CTAB‐CPT was subsequently used to prepare agarose hydrogels containing a small content (≤ 0.3 wt %) of κ‐carrageenan, an anionic water‐soluble polysaccharide. The release of CPT from so fabricated hydrogel‐surfactant systems has been investigated by varying the content of κ‐carrageenan in the hydrogel. It was observed that the presence of κ‐carrageenan in the hydrogel system resulted in a significant decrease in the release rate of the drug. This effect was ascribed to the ionic interaction between the positively charged surfactant micelles and the negatively charged κ‐carrageenan. The release profiles were fitted to two mathematic models of diffusion and the diffusion coefficients of the drug were obtained as a function of κ‐carrageenan content. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Corrosion behavior and biocompatibility of nanostructured TiO2 film on Ti6Al4V
Authors: Karpagavalli Ramji , Zhou Anhong , Chellamuthu Prithiviraj , Nguyen Kytai 
Published: June 2007

AbstractThe corrosion behavior and cell adhesion property of nanostructured TiO2 films deposited electrolytically on Ti6Al4V were examined in the present in vitro study. The nanostructured TiO2 film deposition on Ti6Al4V was achieved via peroxoprecursors. SEM micrographs exhibit the formation of amorphous and crystallite TiO2 nanoparticles on Ti6Al4V before and after being annealed at 500°C. Corrosion behavior of TiO2‐deposited and uncoated Ti6Al4V was evaluated in freely aerated Hank's solution at 37°C by the measurement and analysis of open‐circuit potential variation with time, Tafel plots, and electrochemical impedance spectroscopy. The electrochemical results indicated that nano‐TiO2 coated Ti6Al4V showed a better corrosion resistance in simulated biofluid than uncoated Ti6Al4V. Rat bone cells and human aortic smooth muscle cells were grown on these substrates to study the cellular responses in vitro. The SEM images revealed enhanced cell adhesion, cell spreading, and proliferation on nano‐TiO2 coated Ti6Al4V compared to those grown on uncoated substrates for both cell lines. These results suggested that nanotopography produced by deposition of nanostructured TiO2 onto Ti alloy surfaces might enhance corrosion resistance, biocompatibility, and cell integration for implants made of Ti alloys. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Surface modification of poly(L‐lactic acid) by entrapment of chitosan and its derivatives to promote osteoblasts‐like compatibility
Authors: Liu Zonghua , Jiao Yanpeng , Zhang Ziyong , Zhou Changren 
Published: June 2007

AbstractSurface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly(L‐lactic acid) (PLLA) films, chitosan and its derivatives, carboxymethyl chitosan (CMC) and N‐methylene phosphonic chitosan (NPC), were used to modify the surface of PLLA films by an entrapment method. The surface properties of original and modified PLLA films were measured by using water contact angle measurement and X‐ray photoelectron spectroscopy (XPS). Subsequently, the cytocompatibility of these PLLA films was investigated by testing osteoblasts‐like cytocompatibility, cell attachment, cell proliferation, alkaline phosphatase activity, and cell cycle. Experimental results indicated that the hydrophilicity of the modified films was improved and the surface of the modified PLLA films became enriched with chitosan and its derivatives. Moreover, the surface modification with chitosan and its derivatives significantly promoted osteoblasts‐like compatibility of PLLA films. This surface modification, combining the individual advantages of PLLA with good mechanical property and chitosan as well as its derivatives with good cytocompatibility, is a promising method to prepare desirable biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Physical adsorption of human thrombomodulin (ART‐123) onto polymeric biomaterials for developing an antithrombogenic blood‐contacting material
Authors: Matsusaki Michiya , Omichi Masaaki , Maruyama Ikuro , Akashi Mitsuru 
Published: June 2007

AbstractHuman thrombomodulin (hTM) is an endothelial cell‐associated protein with potent natural anticoagulant activity by converting thrombin from a procoagulant protease to an anticoagulant. ART‐123 is a recombinant soluble hTM (amino acid residues 1‐498), and we focused on the physical adsorption of ART‐123 onto a polymeric biomaterial surface to develop an antithrombogenic blood‐contacting material with preventing the denaturation of hTM and the remaining chemical reagents. The adsorption of hTM onto polysulfone (PSF) films was analyzed quantitatively by quartz crystal microbalance analysis. The adsorption constant and the maximum adsorption amount, calculated by the assumption of a Langmuir‐type adsorption, showed that hTM adsorbed with a relatively weak interaction onto the PSF film. The hydrophilic protein lysozyme also showed a Langmuir‐type monolayer adsorption, although hydrophobic catalase and fibrinogen showed multilayer adsorption accompanying the denaturation. The physically adsorbed hTM showed high coenzymatic activity for the activation of protein C, as well as anticoagulant activity. Furthermore, the surface wettability of the PSF film was easily controllable by the physical adsorption of hydrophobic and hydrophilic bioactive proteins. The physical adsorption of hTM or bioactive proteins onto polymeric biomaterials will be instrumental for developing an antithrombogenic blood‐contacting biomaterial, and for controlling the surface properties of biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
In silico modulation of apoptotic Bcl‐2 proteins by mistletoe lectin‐1: Functional consequences of protein modifications
Authors: Khwaja Tasneem A. , Wajahat Tayyaba , Ahmad Ishtiaq , Hoessli Daniel C. , Walker‐Nasir Evelyne , Kaleem Afshan , Qazi Wajahat M. , Shakoori Abdul R. , Din Nasir‐ud‐ 
Published: June 2007

AbstractThe mistletoe lectin‐1 (ML‐1) modulates tumor cell apoptosis by triggering signaling cascades through the complex interplay of phosphorylation and O‐linked N‐acetylglucosamine (O‐GlcNAc) modification in pro‐ and anti‐apoptotic proteins. In particular, ML‐1 is predicted to induce dephosphorylation of Bcl‐2‐family proteins and their alternative O‐GlcNAc modification at specific, conserved Ser/Thr residues. The sites for phosphorylation and glycosylation were predicted and analyzed using Netphos 2.0 and YinOYang 1.2. The involvement of modified Ser/Thr, and among them the potential Yin Yang sites that may undergo both types of posttranslational modification, is proposed to mediate apoptosis modulation by ML‐1. J. Cell. Biochem. 103: 479–491, 2008. © 2007 Wiley‐Liss, Inc.
Angiogenic CXC chemokine expression during differentiation of human mesenchymal stem cells towards the osteoblastic lineage
Authors: Bischoff D.S. , Zhu J.H. , Makhijani N.S. , Kumar A. , Yamaguchi D.T. 
Published: June 2007

AbstractThe potential role of ELR+CXC chemokines in early events in bone repair was studied using human mesenchymal stem cells (hMSCs). Inflammation, which occurs in the initial phase of tissue healing in general, is critical to bone repair. Release of cytokines from infiltrating immune cells and injured bone can lead to recruitment of MSCs to the region of repair. CXC chemokines bearing the Glu‐Leu‐Arg (ELR) motif are also released by inflammatory cells and serve as angiogenic factors stimulating chemotaxis and proliferation of endothelial cells. hMSCs, induced to differentiate with osteogenic medium (OGM) containing ascorbate, β‐glycerophosphate (β‐GP), and dexamethasone (DEX), showed an increase in mRNA and protein secretion of the ELR+CXC chemokines CXCL8 and CXCL1. CXCL8 mRNA half‐life studies reveal an increase in mRNA stability upon OGM stimulation. Increased expression and secretion is a result of DEX in OGM and is dose‐dependent. Inhibition of the glucocorticoid receptor with mifepristone only partially inhibits DEX‐stimulated CXCL8 expression indicating both glucocorticoid receptor dependent and independent pathways. Treatment with signal transduction inhibitors demonstrate that this expression is due to activation of the ERK and p38 mitogen‐activated protein kinase (MAPK) pathways and is mediated through the Gαi‐coupled receptors. Angiogenesis assays demonstrate that OGM‐stimulated conditioned media containing secreted CXCL8 and CXCL1 can induce angiogenesis of human microvascular endothelial cells in an in vitro Matrigel assay. J. Cell. Biochem. 103: 812–824, 2008. © 2007 Wiley‐Liss, Inc.
Prenatal sonographic diagnosis of congenital heart disease and intrauterine growth restriction: A case–control study
Authors: Perez‐Delboy Annette , Simpson Lynn L. 
Published: June 2007

AbstractPurposeTo determine the prevalence of intrauterine growth restriction (IUGR) in cases of congenital heart disease (CHD) and to evaluate whether the prenatal diagnosis of isolated CHD was a significant risk factor for IUGR.MethodsWe conducted a retrospective case–control study of prenatally detected CHD with delivery at ≥20 weeks' gestation between January 1, 1998, and December 31, 2001. Four groups were analyzed: (1) all cases with CHD, (2) after exclusion of abnormal karyotype, (3) after exclusion of abnormal karyotype and prenatally diagnosed extracardiac anomaly, and (4) after exclusion of abnormal karyotype and prenatally and postnatally diagnosed extracardiac anomaly. The prevalence of IUGR was determined in each of the 4 study groups and was compared with controls.ResultsThere were 13,395 deliveries at ≥20 weeks' gestation. Of the 180 cases of CHD, 22.8% were associated with IUGR compared with 11.6% of controls (p < 0.01). In contrast, there was no statistically significant difference in the prevalence of IUGR in the 140 cases of isolated CHD compared with controls (12.9% versus 10.0%).ConclusionThe prenatal detection of isolated CHD does not seem to be associated with IUGR. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Sonographic appearance of ruptured ovarian cyst in the neonatal period
Authors: Gallagher Thomas A. , Lim‐Dunham Jennifer E. , Vade Aruna , Smith Sara , Salhadar Alia , Ward Kathleen A. 
Published: June 2007

AbstractRupture is a rare complication of ovarian cysts diagnosed during the prenatal period. We present a case that focuses on the postnatal sonographic appearance of rupture of an ovarian cyst after vaginal delivery. Histopathologic correlation is provided. The main sonographic features include complicated ascites and a collapsed cystic structure in the abdomen. Ruptured ovarian cyst should be included in the differential diagnosis of unexplained ascites in a newborn girl. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Routine intraoperative Doppler sonography in the evaluation of complications after living‐related donor liver transplantation
Authors: Choi Jin‐Young , Lee Jae Young , Lee Jeong Min , Kim Se Hyung , Lee Min Woo , Han Joon Koo , Choi Byung Ihn 
Published: June 2007

AbstractPurposeTo determine whether quantitative and qualitative analysis of intraoperative Doppler sonography data are predictive of vascular complications after living‐related donor liver transplantation.MethodsIntraoperative sonograms of 81 transplanted livers (right lobe in 61 patients, left lobe in 20 patients) were analyzed for the presence of blood flow, resistance index, systolic acceleration time (SAT), peak systolic velocity, and morphologic characteristics of spectral waveform of the hepatic artery. Peak velocity and spectral waveforms of portal and hepatic veins were also analyzed. Intraoperative sonography results were compared with information obtained with multidetector‐row CT (MDCT) angiography or conventional angiography. The time interval between operation and angiography ranged from 1 to 23 days (mean, 8.5 days).ResultsHepatic artery stenosis (HAS) was identified in 20 patients via MDCT angiography, conventional angiography, or both. The Doppler parameters found helpful for predicting HAS were tardus‐parvus pattern and delayed SAT. The sensitivity, specificity, and negative predictive value (NPV) were 60.0%, 73.7%, and 84.9%, respectively, for tardus‐parvus pattern and 40.0%, 83.6%, and 80.9%, respectively, for delayed SAT. Peak velocities of the portal and hepatic veins were not reliable indicators of vascular complication. Loss of triphasity of the hepatic vein had a 98.4% NPV for venous obstruction.ConclusionsDelayed SAT of the hepatic artery and loss of triphasity of the hepatic vein had a >80% for specificity for predicting vascular complications. Tardus‐parvus pattern, delayed SAT of the hepatic artery, and loss of triphasity of the hepatic vein showed an acceptable NPV for identifying vascular complications. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Sonographic diagnosis of inferior mesenteric artery aneurysm and marginal artery of Drummond
Authors: Momin Asif A. , Chaubal Nitin G. , Saifi Shenaz G. A. , Kazi Zubair N. 
Published: June 2007

AbstractWe report the case of a patient in whom sonographic examination revealed an aneurysm of the inferior mesenteric artery with severe proximal stenosis and poststenotic dilatation—the enlargement of the proximal portion of the artery of Drummond. This collateral pathway should be kept in mind when studying bowel ischemia, especially when stenosis is present or when there is occlusion of the superior mesenteric artery. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Pyruvate transport in isolated cardiac mitochondria from two species of amphibian exhibiting dissimilar aerobic scope: Bufo marinus and Rana catesbeiana
Authors: Duerr Jeffrey M. , Tucker Kristina 
Published: June 2007

AbstractCardiac mitochondria were isolated from Bufo marinus and Rana catesbeiana, two species of amphibian whose cardiovascular systems are adapted to either predominantly aerobic or glycolytic modes of locomotion. Mitochondrial oxidative capacity was compared using VO2 max and respiratory control ratios in the presence of a variety of substrates including pyruvate, lactate, oxaloacetate, β‐hydroxybutyrate, and octanoyl‐carnitine. B. marinus cardiac mitochondria exhibited VO2 max values twice that of R. catesbeiana cardiac mitochondria when oxidizing carbohydrate substrates. Pyruvate transport was measured via a radiolabeled‐tracer assay in isolated B. marinus and R. catesbeiana cardiac mitochondria. Time‐course experiments described both α‐cyano‐4‐hydroxycinnamate‐sensitive (MCT‐like) and phenylsuccinate‐sensitive pyruvate uptake mechanisms in both species. Pyruvate uptake by the MCT‐like transporter was enhanced in the presence of a pH gradient, whereas the phenylsuccinate‐sensitive transporter was inhibited. Notably, anuran cardiac mitochondria exhibited activities of lactate dehydrogenase and pyruvate carboxylase. The presence of both transporters on the inner mitochondrial membrane affords the net uptake of monocarboxylates including pyruvate, β‐hydroxybutyrate, and lactate; the latter potentially indicating the presence of a lactate/pyruvate shuttle allowing oxidation of extramitochondrial NADH. Intramitochondrial lactate dehydrogenase and pyruvate carboxylase enables lactate to be oxidized to pyruvate or converted to anaplerotic oxaloacetate. Kinetics of the MCT‐like transporter differed significantly between the two species, suggesting differences in aerobic scope may be in part attributable to differences in mitochondrial carbohydrate utilization. J. Exp. Zool. 307A:425–438, 2007. © 2007 Wiley‐Liss, Inc.
Hairpin DNAzymes: a new tool for efficient cellular gene silencing
Authors: Abdelgany Amr , Wood Matthew , Beeson David 
Published: June 2007

AbstractBackgroundRNA‐based gene silencing is potentially a powerful therapeutic strategy. Catalytic 10–23 DNAzymes bind to target RNA by complimentary sequence arms on a Watson‐Crick basis and thus can be targeted to effectively cleave specific mRNA species. However, for in vivo applications it is necessary to stabilise DNAzymes against nucleolytic attack. Chemical modifications can be introduced into the binding arms to increase stability but these may alter catalytic activity and in some cases increase cell toxicity.MethodsWe designed novel 10–23 DNAzyme structures that incorporate stem‐loop hairpins at either end on the DNAzyme binding arms. The catalytic activity of hairpin DNAzymes (hpDNAzyme) were tested in vitro against 32P‐labelled cRNA encoding the muscle acetylcholine receptor (AChR) α‐subunit. Resistance of hpDNAzymes to nucleolytic degradation was tested by incubation of the hpDNAzymes with Bal‐31, DNase1 or HeLa cell extract. Gene silencing by hpDNAzymes was assessed by measuring reduced fluorescence from DsRed2 and EGFP reporters in cell culture systems, and reduced 125I‐alpha‐bungarotoxin binding in cells transfected with cDNA encoding the AChR.ResultsWe show that hpDNAzymes show remarkable resistance to nucleolytic degradation, and demonstrate that in cell culture systems the hpDNAzymes are far more effective than standard 10–23 DNAzymes in down‐regulating protein expression from target mRNA species.ConclusionhpDNAzymes provide new molecular tools that, without chemical modification, give highly efficient gene silencing in cells, and may have potential therapeutic applications. Copyright © 2007 John Wiley & Sons, Ltd.
Neuron‐specific delivery of nucleic acids mediated by Tet1‐modified poly(ethylenimine)
Authors: Park In‐Kyu , Lasiene Jurate , Chou Shinn‐Huey , Horner Philip J. , Pun Suzie H. 
Published: June 2007

AbstractBackgroundThe development of minimally invasive, non‐viral gene delivery vehicles for the central nervous system (CNS) is an important technology goal in the advancement of molecular therapies for neurological diseases. One approach is to deliver materials peripherally that are recognized and retrogradely transported by motor neurons toward the CNS. Tet1 is a peptide identified by Boulis and coworkers to possess the binding characteristics of tetanus toxin, which interacts specifically with motor neurons and undergoes fast, retrograde delivery to cell soma. In this work, Tet1‐poly(ethylenimine) (Tet1‐PEI) was synthesized and evaluated as a neurontargeted delivery vehicle.MethodsTet1‐PEI and NT‐PEI (neurotensin‐PEI) were synthesized and complexed with plasmid DNA to form polyplexes. Polyplexes were assessed for binding and uptake in differentiated neuron‐like PC‐12 cells by flow cytometry and confocal microscopy. In order to determine gene delivery efficiency, polyplexes were exposed to PC‐12 cells at various stages of differentiation. Targeted binding of polyplexes with primary neurons was studied using dorsal root ganglion cells.ResultsTet1‐PEI and NT‐PEI polyplexes bound specifically to differentiated PC‐12 cells. The specificity of the interaction was confirmed by delivery to non‐neuronal cells and by competition studies with free ligands. Tet1‐PEI polyplexes preferentially transfected PC‐12 cells undergoing NGF‐induced differentiation. Finally, neuron‐specific binding of Tet1‐PEI polyplexes was confirmed in primary neurons.ConclusionsThese studies demonstrate the potential of Tet1‐PEI as a neuron‐targeted material for non‐invasive CNS delivery. Tet1‐PEI binds specifically and is internalized by neuron‐like PC‐12 cells and primary dorsal root ganglion. Future work will include evaluation of siRNA delivery with these vectors. Copyright © 2007 John Wiley & Sons, Ltd.