bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decellularized, xenogeneic small‐diameter arteries: Transition from a muscular to an elastic phenotype in vivo
Authors: Bergmeister Helga , Plasenzotti Roberto , Walter Ingrid , Plass Christian , Bastian Fabienne , Rieder Erwin , Sipos Wolfgang , Kaider Alexandra , Losert Udo , Weigel Guenter 
Published: April 2008

AbstractReports regarding the biocompatibility of xenogeneic, decellularized bioprosthetic implants differ between bioinertness and complete graft degradation. We investigated heparin‐crosslinked and nonheparinized, xenogeneic vascular substitutes in a rat model. Porcine arteries (15 × 1.5 mm) were decellularized by multistep detergent and enzymatic techniques, which were followed by heparin‐crosslinking in 50% of the implants. Prostheses were implanted into the abdominal aorta of 76 rats for 1 day and up to 6 months. Retrieved specimens were evaluated by histology, immunohistochemistry, laser scanning, and scanning electron microscopy. Graft patency did not differ between groups (97.3%). Heparinized grafts showed a statistically significant lower rate of aneurysm formation (p = 0.04 %). Implants revealed infiltration with granulocytes and macrophages up to 3 months. Recellularization with endothelial cells and myofibroblasts was detectable within 1 month. After 6 months elastin biosynthesis and complete graft remodeling toward an elastic vessel was evident. These results indicate that temporary inflammation does not interfere with long‐term vascular remodeling. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Sol–gel processed porous silica carriers for the controlled release of diclofenac diethylamine
Authors: Czarnobaj Katarzyna , Czarnobaj Joanna 
Published: April 2008

AbstractSilica xerogels doped with diclofenac diethylamine were prepared by the sol–gel method from a hydrolysed tetraethoxysilane (TEOS) solution containing diclofenac diethylamine. Two different catalysts, drying conditions and levels of water content were used to alter the microstructure of the silica xerogels. The aim of this study was to determine the rate of Diclofenac release from the silica xerogels. This in vitro study showed that the sol–gel method is useful for entrapping Diclofenac in the pores of xerogels. It also showed that, in vitro, Diclofenac is released from the silica xerogel, through the pores, by diffusion. Base‐catalysed gels proved to be much more effective than acid‐catalyzed gels. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Fabrication of porous, drug‐releasing, biodegradable, polymer scaffolds for sustained drug release
Authors: Uttarwar Mayur , Aswath Pranesh 
Published: April 2008

AbstractTwo different approaches were used to fabricate porous scaffolds, and their in vitro drug releasing characteristics were examined. In the first method, a poly(L‐lactic acid) (PLLA) solution and poly(vinyl alcohol) (PVA) + acetaminophen solution was homogenized. The emulsion was then blended with a PLLA solution in chloroform. The resultant emulsion was freeze‐dried to form porous scaffolds. Various combinations were obtained by varying homogenizer speed and blender speed, and by varying the concentration of PVA and acetaminophen solutions. The in vitro drug‐release study was performed for 6 days in a phosphate buffer. The influence of structure, porosity, and drug concentration of the scaffolds on drug‐release rate was examined using design of experiments. In the second approach, scaffolds were prepared in layered constructs, with either a three‐layered or five‐layered structure. The PVA + acetaminophen solution was blended with PLLA solution using a blender. The drug‐release study was performed for 19 days. The effect of drug concentration, blender speed, and the thickness of the layers on drug‐release rate was examined. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Evaluation of a synthetic vertebral body augmentation model for rapid and reliable cyclic compression life testing of materials for balloon kyphoplasty
Authors: Lewis Gladius , Schwardt Jeffrey D. , Slater Thomas A. , Janna Si 
Published: April 2008

AbstractScreening of augmentation materials for use in balloon kyphoplasty (BKP) may be carried out using vertebral bodies (VBs) prepared from fresh cadaveric or animal model spines, but this approach has many drawbacks. Alternatively, a validated synthetic VB augmentation model may be used. In the present work, such a model—a cube (26 mm sides) of low‐density polyurethane foam with a centrally located through‐thickness cylindrical hole (diameter = 4 mm) completely filled with a bolus of augmentation material—was used to compare two BKP augmentation materials with very different chemistries (a high‐viscosity acrylic bone cement (PMMA) and a calcium phosphate bone substitute (CP)) in cyclic compression life tests. The test conditions were considered physiologically relevant: the model was immersed in phosphate buffered saline solution, at 37°C; the frequency was 3 Hz; and the maximum load was either 1150 N or 2300 N (corresponding to a maximum stress of 1.7 or 3.4 MPa). At the high load, all four PMMA and two out of seven CP specimens ran out to 1 million cycles. CP specimens consistently ran out at the low load. The use of this model for rapid and reliable ex vivo screening of BKP augmentation materials was considered both valid (because of the clear demarcation seen in the qualitative and quantitative results obtained with the two materials tested) and appropriate (that is, clinically relevant to BKP). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Biomechanical and histomorphometric study of dental implants with different surface characteristics
Authors: Yeo In‐Sung , Han Jung‐Suk , Yang Jae‐Ho 
Published: April 2008

AbstractThe aim of this study was to investigate the early bone response to the titanium dental implants with different surface characteristics using the rabbit tibia model. Calcium metaphosphate coated, anodic oxidized, hydroxyapatite particle‐blasted, and turned (control) surfaces were compared. Surface topography was evaluated by field emission scanning electron microscope and optical interferometer. Eighteen rabbits received 72 implants in the tibia. Resonance frequency was analyzed every week for 6 weeks. Removal torque values were measured 2 and 6 weeks after placement. The implant–bone interfaces were directly observed by light microscope and bone‐to‐implant contact ratios were measured 2 and 6 weeks after insertion. All the surface‐modified implants showed superior initial bone responses to the control. No significant differences were found among the surface‐modified groups. Data suggest that various surface modification methods can provide favorable bone responses for early functioning and healing of dental implants. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
New polymer for intra‐abdominal meshes—PVDF copolymer
Authors: Conze Joachim , Junge Karsten , Weiß Claudia , Anurov Michael , Oettinger Alexander , Klinge Uwe , Schumpelick V. 
Published: April 2008

AbstractPurpose:Full tissue integration without adhesion formation is still a challenge for intra‐abdominal mesh materials. Purpose of this study was to investigate the adhesive potential and fibrocollagenous ingrowth of a polymer blend of polyvinylidene fluoride and hexafluorpropylene (co‐PVDF), an established suture material in vascular surgery, when placed as a mesh in the intra‐abdominal position. The results were compared with a matching polypropylene (PP) mesh.Methods:In an established rabbit model, mesh implantation was performed by laparoscopy in the intraperitoneal onlay mesh technique. After 7, 21, and 90 days the degree of adhesion formation, foreign body reaction, bridging, and shrinkage of mesh area were investigated.Results:In the early phase after 7 and 21 days we found significantly more adhesions for PP, but no differences after 90 days. Analysis of tissue reaction showed a significantly lower fibrotic reaction for co‐PVDF. The degree of shrinkage revealed no significant difference.Conclusion:Large‐pore PP and co‐PVDF‐meshes showed comparable good results in the intra‐abdominal position, with a reduced inflammatory tissue reaction for co‐PVDF. Large pore meshes should be considered an alternative for the development of intraperitoneal onlay meshes. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Control of the blood–polymer interface by plasma treatment
Authors: Dumitrascu Nicoleta , Borcia Catalin , Borcia Gabriela 
Published: April 2008

AbstractPlasma that is generated using dielectric barrier discharge is used to modify the surface properties of polymers used in medicine, at atmospheric pressure. Treatments are performed on films of polyamide‐6, high density polyethylene, polymethylmetacrylate, and polytetrafluorethylene, selected for their medical applications. The plasma treatment conditions are discussed, in relation with relevant parameters for the adhesion properties, like the surface energy components, interfacial tension, surface topography, structural changes, and chemical composition. The interface properties are analyzed using the most important fluids implicated in the interfacial events related to the coagulation process at the interface of blood–polymer surface, respectively, water, whole blood, fibrinogen, and albumin. The physical and chemical modification of the surface is theoretically favorable to the interaction of the polymer with the blood and its components, by means of interfacial tension reduction, polarity increase, cleaning, ordering of molecular chains, functionalization, and stabilization effects. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Novel composite hyaluronan/type I collagen/fibrin scaffold enhances repair of osteochondral defect in rabbit knee
Authors: Filová Eva , Jelínek František , Handl Milan , Lytvynets Andriy , Rampichová Michala , Varga Ferdinand , Činátl Jaroslav , Soukup Tomáš , Trč Tomáš , Amler Evžen 
Published: April 2008

AbstractA new composite scaffold containing type I collagen, hyaluronan, and fibrin was prepared with and without autologous chondrocytes and implanted into a rabbit femoral trochlea. The biophysical properties of the composite scaffold were similar to native cartilage. The macroscopic, histological, and immunohistochemical analysis of the regenerated tissue from cell‐seeded scaffolds was performed 6 weeks after the implantation and predominantly showed formation of hyaline cartilage accompanied by production of glycosaminoglycans and type II collagen with minor fibro‐cartilage production. Implanted scaffolds without cells healed predominantly as fibro‐cartilage, although glycosaminoglycans and type II collagen, which form hyaline cartilage, were also observed. On the other hand, fibro‐cartilage or fibrous tissue or both were only formed in the defects without scaffold. The new composite scaffold containing collagen type I, hyaluronan, and fibrin, seeded with autologous chondrocytes and implanted into rabbit femoral trochlea, was found to be highly effective in cartilage repair after only 6 weeks. The new composite scaffold can therefore enhance cartilage regeneration of osteochondral defects, by the supporting of the hyaline cartilage formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Runoff sediment particle sizes associated with soil erosion in the Lake Tahoe Basin, USA
Authors: Grismer M. E. , Ellis A. L. , Fristensky A. 
Published: April 2008

AbstractRunoff sediment from disturbed soils in the Lake Tahoe Basin has resulted in light scattering, accumulation of nutrients, and subsequent loss in lake clarity. Little quantified information about erosion rates and runoff particle‐size distributions (PSDs) exists for determining stream and lake loading associated with land management. Building on previous studies using rainfall simulation (RS) techniques for quantifying infiltration, runoff, and erosion rates, we determine the dependence and significance of runoff sediment PSDs and sediment yield (SY, or erodibility) on slope and compare these relationships between erosion control treatments (e.g., mulch covers, compost, or woodchip incorporation, plantings) with bare and undisturbed, or ‘native’ forest soils. We used simulated rainfall rates of 60–100 mm h−1 applied over replicated 0·64 m2 plots. Measured parameters included time to runoff (s), infiltration and runoff rates (mm h−1), SY (g mm−1 runoff), and average sediment concentration (SC, g L−1) as well as PSDs in runoff samples. In terms of significant relationships, granitic soils had larger particle sizes than volcanic soils in bulk soil and runoff samples. Consequently, runoff rates, SCs, and SYs were greater from bare volcanic as compared to that from bare granitic soils at similar slopes. Generally, runoff rates increased with increasing slope on bare soils, while infiltration rates decreased. Similarly, SY increased with slope for both soil types, though SYs from volcanic soils are three to four times larger than that from granitic soils. As SY increased, smaller particle sizes are observed in runoff for all soil conditions and particle sizes decreased with increasing slope. Copyright © 2008 John Wiley & Sons, Ltd.
Factors affecting the dissolution of copper in transformer oils
Authors: Kalantar A. , Levin M. 
Published: April 2008

AbstractThe effect of addition of acids, peroxides and model N‐containing compounds to the oils on the rate of the copper dissolution from a copper strip into the oils was studied. The oils used were poly‐alpha‐olefin 2 (PAO‐2) and a highly refined naphthenic oil. Acids and peroxides were found to increase the copper dissolution into the oil, whereas the model nitrogen‐containing compounds exhibited a surface passivatory effect. The presence of the oil's partial oxidation products was found to increase the dissolution of the copper into the oil. The reasons for these observations are discussed. The relative contribution of the electrochemical and chemical processes to the copper corrosion is discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Quantification of free and protein‐bound trans‐resveratrol metabolites and identification of trans‐resveratrol‐C/O‐conjugated diglucuronides – Two novel resveratrol metabolites in human plasma
Authors: Burkon Alexander , Somoza Veronika 
Published: April 2008

AbstractThe polyphenol trans‐resveratrol (t‐RES) is present as t‐RES‐3‐O‐β‐D‐glycoside, termed piceid, in several plant‐derived foods. Although data on the metabolism and on in vivo effects of t‐RES have been reported, quantitative data on the metabolites formed after dietary intake of t‐RES or piceid are still lacking. In this study, 85.5 mg of piceid per 70 kg of body weight (bw) were administered to healthy volunteers in a bolus dose. t‐RES metabolites formed in plasma and urine were identified and quantified by LC‐MS/MS, NMR, and HPLC‐DAD analysis using chemically synthesized t‐RES conjugate standards. In addition, the amount of t‐RES metabolites bound noncovalently to plasma proteins was determined for the first time in humans. The metabolites identified and quantified were t‐RES‐3‐sulfate, t‐RES‐3,4′‐disulfate, t‐RES‐3,5‐disulfate, t‐RES‐3‐glucuronide and t‐RES‐4′‐glucuronide, with t‐RES‐sulfates being the dominant conjugates in plasma and urine. Besides these metabolites, two novel t‐RES‐C/O‐conjugated diglucuronides have been identified and quantified in plasma and urine. Moreover, it could be shown that up to 50% of the plasma t‐RES‐3‐sulfate, t‐RES‐disulfates, and the novel t‐RES‐C/O‐diglucuronides were bound to proteins. Total recovery of the dietary administered piceid in urine ranged between 13.6 and 35.7%.
Rotationally oscillating drill (Ros‐Drill©) for mouse icsi without using mercury
Authors: Ergenc Ali Fuat , Li Ming‐Wen , Toner Mehmet , Biggers John D. , Lloyd K.C. Kent , Olgac Nejat 
Published: April 2008

AbstractIntracytxoplasmic sperm injection (ICSI) is an important assisted reproductive technology (ART). Due to deployment difficulties and low efficiency of the earlier (conventional) version of ICSI, especially in the mouse, a piezo‐assisted ICSI technique had evolved as a popular ART methodology in recent years. An important and remaining problem with this technique, however, is that it requires small amounts of mercury to stabilize the pipette tip when piezoelectric force pulses are applied. To eliminate this problem we developed and tested a completely different and mercury‐free technology, called the “Ros‐Drill©” (rotationally oscillating drill). The technique uses microprocessor‐controlled rotational oscillations on a spiked micropipette without mercury or piezo. Preliminary experimental results show that this new microinjection technology gives high survival rate (>70% of the injected oocytes) and fertilization rate (>80% of the survived oocytes), and blastocyst formation rates in early trials (∼50% of the survived oocytes). Blastocysts created by Ros‐Drill© ICSI were transferred into the uteruses of pseudopregnant surrogate mothers and healthy pups were born and weaned. The Ros‐Drill© ICSI technique is automated and therefore; it requires a very short preliminary training for the specialists, as evidenced in many successful biological trials. These advantages of Ros‐Drill© ICSI over conventional and piezo‐assisted ICSI are clearly demonstrated and it appears to have resolved an important problem in reproductive biology. Mol. Reprod. Dev. 75: 1744–1751, 2008. © 2008 Wiley‐Liss, Inc.
Serum leptin in first‐trimester Down syndrome pregnancies
Authors: Hedley Paula , Christiansen Michael 
Published: April 2008

AbstractBackgroundLeptin is a key regulator of satiety; and the serum concentration is considered to reflect nutritional status. Expressed predominantly by the adipocytes, leptin is also expressed in placenta, which is a major source of both leptin and the leptin receptor in pregnancy serum. As a placenta protein, leptin serum concentrations may be perturbed in Down syndrome (DS) pregnancies as seen for pregnancy‐associated plasma protein‐A (PAPP‐A) and human chorionic gonadotrophin‐β (hCGβ). We examined whether leptin is a maternal serum marker for foetal DS in the first trimester.Materials and MethodsSerum samples from 44 pregnant women with a DS foetus, and 135 control pregnant women in week 8 to 14 had the leptin concentration determined by immunoassay and the concentrations were converted into multiples of the median (MoM) of controls based on log‐regression analysis. The distributions of log10 MoM leptin was compared in DS and control pregnancies.ResultsSerum leptin increased significantly with gestational age in controls (p = 0.02). The mean log10 MoM in controls was − 0.0486, with a median empirical MoM of 0.89, and − 0.0618, with a median empirical MoM of 0.80, in DS pregnancies. This difference was not significant. The log10 MoM leptin values in DS pregnancies did not change with gestational age (p = 0.32).ConclusionLeptin is not a first‐trimester marker for foetal DS. Copyright © 2008 John Wiley & Sons, Ltd.
Polymorphisms in genes related to folate and cobalamin metabolism and the associations with complex birth defects
Authors: Brouns R. , Ursem N. , Lindemans J. , Hop W. , Pluijm S. , Steegers E. , Steegers‐Theunissen R. 
Published: April 2008

AbstractObjectiveTo investigate the associations between biomarkers and genetic variants involved in homocysteine metabolism and the risk of complex birth defects.MethodsTotal homocysteine (tHcy), folate, cobalamin, apo‐transcobalamin (apo‐TC) and apo‐haptocorrin (apo‐HC) were measured in the amniotic fluid of 82 women who were pregnant with a child having a complex birth defect, such as neural tube defect, cleft lip and/or palate, heart defect or omphalocele, and in 110 women pregnant with a non‐malformed child. The determined genotypes of the child comprised of 5, 10‐methylenetetrahydrofolate reductase (MTHFR 677C > T, 1298A > C), methionine synthase (MTR 2756A > G), methionine synthase reductase (MTRR 66A > G) and transcobalamin (TCN2 776C > G). Univariate and multivariate logistic regression analyses were performed.ResultsSignificantly lower cobalamin and higher apo‐TC, apo‐HC, tHcy and folate concentrations were determined in amniotic fluids of cases compared with controls (p⩽0.001). Logistic regression analysis revealed that after adjustment for maternal age, children carrying the MTHFR 677T allele showed a four‐fold increased risk of having a complex birth defect, OR (95% CI) = 4.0 (1.1–15.4). Other genotypes did not show significant associations.ConclusionThe MTHFR 677C > T polymorphism in conjunction with reduced folate‐ and/or cobalamin status may increase the risk of complex birth defects. Copyright © 2008 John Wiley & Sons, Ltd.
Enrichment of collagen plugs with platelets and amniotic fluid cells increases cell proliferation in sealed iatrogenic membrane defects in the foetal rabbit model
Authors: Liekens Daisy , Lewi Liesbeth , Jani Jacques , Heyns Liesbeth , Poliard Eline , Verbist Godelieve , Ochsenbein‐Kölble Nicole , Hoylaerts Marc , Deprest Jan 
Published: April 2008

AbstractObjectivesThe purpose of this study was to evaluate cell proliferation in platelet‐enriched collagen plugs with and without addition of amniotic fluid‐derived heterologous foetal cells to seal an iatrogenic membrane defect in the foetal rabbit model.MethodsAmniotic fluid cells were harvested from three donor does at 23 days of gestation (term = 32 days) and labelled with carboxyfluorescein diacetate succinimidyl ester (CFDA‐SE). In 42 other does, foetal membrane defects were induced by foetoscopic needle puncture at 23 days of gestation, and closed with either a platelet‐enriched collagen plug with (n = 44) or without (n = 32) amniotic fluid cells. At 30 days of gestation, the defects were harvested and assessed microscopically.ResultsThe plugs enriched with heterologous amniotic fluid cells more commonly had proliferating cells in the centre of the plug than those without cell addition. CFDA‐SE labelling confirmed the presence of heterologous amniotic fluid cells over the entire membrane plug. Cell typing showed a mixture of fibroblasts and epithelial cells at the wound edges, whereas in the centre, there was an abundance of fibroblasts.ConclusionWhen sealing iatrogenic membrane defects in the foetal rabbit model, enrichment of collagen plugs with platelets and amniotic fluid‐derived heterologous foetal cells increases local cell proliferation. Copyright © 2008 John Wiley & Sons, Ltd.
What is the role of “pressure” in the use of capillary and slit flows to determine the shear‐rate dependent viscosity of a viscoelastic fluid?
Authors: Han Chang Dae 
Published: April 2008

AbstractThe purpose of this review article is to clear the confusion created by some investigators, who erroneously thought that the pressure transducers mounted on the wall of a capillary or slit die measured a quantity that could meaningfully be called “pressure,” accurately stated “indeterminate isotropic contribution to the total stress,” and then reported on the effect of “pressure” on the shear‐rate dependent viscosity of a viscoelastic fluid. On the other hand, reference to such a quantity is not needed to calculate the wall shear stress and thus shear viscosity in fully developed flow of incompressible, viscoelastic polymer melts in a capillary or slit die; instead only information on the gradient of the total wall normal stress is needed. Further, it is pointed out that much of the literature discussing “pressure shift factor” to describe the effect of “pressure” on the viscosity of polymer melts in flow through a capillary or slit die is based on an erroneous belief that there exists a physically meaningful isotropic “pressure” that can be measured. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.