bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lactoyl‐poloxamine/collagen matrix for cell‐containing tissue engineering modules
Authors: Sosnik Alejandro , Leung Brendan M. , Sefton Michael V. 
Published: October 2007

AbstractCollagen‐containing crosslinked, remodelable poloxamine derivatives were produced by introducing very short oligo(lactic acid) segments through the reaction of poloxamine with L‐lactide and the later addition of unsaturated bonds by the reaction of modified poloxamine with methacryloyl chloride. Degradation studies on discs indicated a faster weight loss in comparison to the stability of lactoyl‐free samples. Cell‐containing modules (both HepG2 cells and two different umbilical vein smooth muscle cell (UVSMC) cell‐types) were produced. Live/Dead assay showed high survival levels for both HepG2 and UVSMC cell types after crosslinking. While nondegradable modules did not change shape over time, lactoyl‐poloxamine matrices showed a gradual shrinkage and size decrease and an increase in the roughness of the surface. These findings were consistent with the expected degradability of the lactoyl derivative. A UVSMC cell line (CRL‐2481) embedded in a LA‐poloxamine/collagen matrix showed the characteristic elongated shape at day 9. UVSMC primary cells behaved in a manner similar to that seen in collagen gels: these cells formed isolated clusters through the matrix that gradually lost viability. On tissue culture polystyrene the same cells aggregated and did not reach confluence. Modules with embedded CRL‐2481 UVSMC led to a better initial adhesion of endothelial cells and a higher extent of surface coverage than seen with the UVSMC‐free system. With embedded primary UVSMC, some EC attachment and formation of gap junctions was seen. The pattern was not well organized. With further improvement (and characterization), the lactoyl poloxamine derivative is potentially useful as a scaffold for modular tissue engineering, when tissue remodeling is an important consideration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Platelet adhesion studies on nanostructured poly(lactic‐co‐glycolic‐acid)–carbon nanotube composite
Authors: Koh Li Buay , Rodriguez Isabel , Zhou Jijie 
Published: October 2007

AbstractDesign of blood‐compatible surfaces is required to minimize platelet–surface interactions and increase the thromboresistance of foreign surfaces. Poly(lactic‐co‐glycolic‐acid)–carbon nanotube (PLGA‐CNT) composite is studied as a building material to fabricate artificial blood prostheses. This nanocomposite‐based biomaterial is prepared by an electrostatic Layer‐by‐Layer (LbL) deposition technique, in which layers of CNTs are adsorbed onto a PLGA film. Before incubation in nonstimulated platelet‐rich plasma (PRP) for platelet studies, fibrinogen is immobilized on PLGA‐CNT composite. Interactions between the plasma proteins, e.g. fibrinogen and PRP, are investigated on the prepared PLGA‐CNT composite. Contact angle measurements on the PLGA‐CNT composite displayed a good resistance of platelets adhesion on a hydrophilic surface with an angle of 64.94° as compared to pristine PLGA control with an angle of 93.43°. A significant reduction of adhesion is observed on the PLGA‐CNT composite, as well as the absence of platelet activation. On the contrary, both platelet adhesion and activation are observed on control samples. We inferred this suppression in secretion of granule contents in the platelet by the presence of the CNTs that resulted in the absence of platelet activation and its subsequent inhibition in the release of adhesive membrane receptors on the PLGA‐CNT composite. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Effects of fluid flow and calcium phosphate coating on human bone marrow stromal cells cultured in a defined 2D model system
Authors: Scaglione S. , Wendt D. , Miggino S. , Papadimitropoulos A. , Fato M. , Quarto R. , Martin I. 
Published: October 2007

AbstractIn this study, we investigated the effect of the long‐term (10 days) application of a defined and uniform level of fluid flow (uniform shear stress of 1.2 × 10−3 N/m2) on human bone marrow stromal cells (BMSC) cultured on different substrates (i.e., uncoated glass or calcium phosphate coated glass, Osteologic™) in a 2D parallel plate model. Both exposure to flow and culture on Osteologic significantly reduced the number of cell doublings. BMSC cultured under flow were more intensely stained for collagen type I and by von Kossa for mineralized matrix. BMSC exposed to flow displayed an increased osteogenic commitment (i.e., higher mRNA expression of cbfa‐1 and osterix), although phenotype changes in response to flow (i.e., mRNA expression of osteopontin, osteocalcin and bone sialoprotein) were dependent on the substrate used. These findings highlight the importance of the combination of physical forces and culture substrate to determine the functional state of differentiating osteoblastic cells. The results obtained using a simple and controlled 2D model system may help to interpret the long‐term effects of BMSC culture under perfusion within 3D porous scaffolds, where multiple experimental variables cannot be easily studied independently, and shear stresses cannot be precisely computed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Self‐assembly multifunctional nanocomposites with Fe3O4 magnetic core and CdSe/ZnS quantum dots shell
Authors: Zhang Ying , Wang Shao‐Ning , Ma Song , Guan Jiao‐Jiao , Li Da , Zhang Xiang‐Dong , Zhang Zhi‐Dong 
Published: October 2007

AbstractThis paper describes a new method for self‐assembling multifunctional nanocomposites with a magnetic core of iron oxide Fe3O4 and a shell of CdSe/ZnS quantum dots (QDs). Two sol–gel processes were applied to form the uniform magnetic seeds (Fe3O4@SiO2‐SH) and then the thiol coordination was used to bind the CdSe/ZnS QDs to the surface of the seeds. The multifunctional nanocomposites were characterized by means of transmission electron microscopy, X‐ray diffraction, energy disperse spectroscopy, fluorescence spectroscopy, infrared spectroscopy, and superconducting quantum interference device (SQUID) magnetometer. The results showed that the magnetic Fe3O4 nanoparticles and the CdSe/ZnS fluorescent QDs were combined together. The nanocomposites were of spherical shape with a mean diameter of 25 nm and exhibited well magnetic response, photostability, chemical activity, and water miscibility. The method put forward here can also be extended to combine systems of other metal oxides and QDs to fabricate core‐shell nanocomposites with multifunction for biomedical applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Estimation of shelf life of natural rubber latex exam‐gloves based on creep behavior
Authors: Das Srilekha Sarkar , Schroeder LeRoy W. 
Published: October 2007

AbstractSamples of full‐length glove‐fingers cut from chlorinated and nonchlorinated latex medical examination gloves were aged for various times at several fixed temperatures and 25% relative humidity. Creep testing was performed using an applied stress of 50 kPa on rectangular specimens (10 mm × 8 mm) of aged and unaged glove fingers as an assessment of glove loosening during usage. Variations in creep curves obtained were compared to determine the threshold aging time when the amount of creep became larger than the initial value. These times were then used in various models to estimate shelf lives at lower temperatures. Several different methods of extrapolation were used for shelf‐life estimation and comparison. Neither Q‐factor nor Arrhenius activation energies, as calculated from 10°C interval shift factors, were constant over the temperature range; in fact, both decreased at lower temperatures. Values of Q‐factor and activation energies predicted up to 5 years of shelf life. Predictions are more sensitive to values of activation energy as the storage temperature departs from the experimental aging data. Averaging techniques for prediction of average activation energy predicted the longest shelf life as the curvature is reduced. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Development of photoreceptor‐specific promoters and their utility to investigate EIAV lentiviral vector mediated gene transfer to photoreceptors
Authors: Nicoud Marjorie , Kong Jian , Iqball Sharifah , Kan On , Naylor Stuart , Gouras Peter , Allikmets Rando , Binley Katie 
Published: October 2007

AbstractBackgroundWe wanted to investigate the ability of recombinant equine infectious anemia virus (EIAV) vectors to transduce photoreceptor cells by developing a series of photoreceptor‐specific promoters that drive strong gene expression in photoreceptor cells.MethodsPromoter fragments derived from the rhodopsin (RHO), the beta phosphodiesterase (PDE) and the retinitis pigmentosa (RP1) genes were cloned in combination with an enhancer element, derived from the interphotoreceptor retinoid‐binding protein gene (IRBP), into luciferase reporter plasmids. An in vitro transient reporter assay was carried out in the human Y‐79 retinoblastoma cell line. The optimal promoters from this screen were then cloned into the recombinant EIAV vector for evaluation in vivo following subretinal delivery into mice.ResultsAll promoters maintained a photoreceptor‐specific expression profile in vitro and the gene expression was further enhanced in combination with the IRBP enhancer. The use of IRBP‐combined RHO or PDE promoters showed modest but exclusive expression in photoreceptors following subretinal delivery to mice. By contrast an EIAV vector containing the cytomegalovirus (CMV) promoter drove reporter gene expression in both photoreceptors and retinal pigment epithelium.ConclusionsIt may be possible to use recombinant EIAV vectors containing photoreceptor‐specific promoters to drive therapeutic gene expression to treat a range of retinal degenerative diseases where the photoreceptor cell is the primary disease target. Copyright © 2007 John Wiley & Sons, Ltd.
MR imaging of hepatocellular carcinoma: Relationship between lesion size and imaging findings, including signal intensity and dynamic enhancement patterns
Authors: van den Bos Indra C. , Hussain Shahid M. , Dwarkasing Roy S. , Hop Wim C.J. , Zondervan Pieter E. , de Man Robert A. , IJzermans Jan N.M. , Walker Craig W. , Krestin Gabriel P. 
Published: October 2007

AbstractPurposeTo assess the relationship between lesion size and MR imaging findings of pathologically‐proven hepatocellular carcinoma (HCC).Materials and MethodsIn a retrospective, single‐center study, 37 consecutive patients were identified between 1999 and 2005 that underwent preoperative MRI and surgical resection of HCC. A total of 47 lesions (mean size = 6.85 cm, range = 1–25 cm) were assessed for signal intensity (SI), enhancement patterns, and secondary morphologic features. Interobserver rating, percentage enhancement, and contrast‐to‐noise‐ratio (CNR) were determined. Lesions were assessed for combinations of typical MRI features. Regression analysis was used to assess relations between MRI findings and tumor size.ResultsOn fat‐suppressed T2‐weighted (T2w) fast‐spin‐echo, smaller lesions had lower SI compared to larger lesions (P < 0.05). In the arterial phase, smaller lesions showed significantly higher percentage enhancement compared to larger lesions (P < 0.05). In the delayed phase, smaller lesions showed less pronounced washout (P < 0.05). Heterogeneity of the lesions, including fatty infiltration, internal nodules, or mosaic pattern, was observed significantly more frequently in larger lesions (P < 0.001). The classic combination of high T2w signal, strong arterial enhancement, and delayed phase washout was present in 23 of 44 lesions (52%).ConclusionSmaller HCC often showed lower SI on T2w, more intense arterial enhancement, and less pronounced delayed washout compared to larger HCC. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
MRI identification of the rostral‐caudal pattern of pathology within the corpus callosum in the cuprizone mouse model
Authors: Wu Qi‐Zhu , Yang Qing , Cate Holly S. , Kemper Dennis , Binder Michele , Wang Hong‐Xin , Fang Ke , Quick Melissa J. , Marriott Mark , Kilpatrick Trevor J. , Egan Gary F. 
Published: October 2007

AbstractPurposeTo characterize and compare histological and MRI‐based changes within the corpus callosum (CC) in the cuprizone mouse model of multiple sclerosis (MS).Materials and MethodsA total of 12 C57/BL6 mice were fed cuprizone from eight weeks of age for four weeks. One cohort of six cuprizone and two control mice were scanned with a T2‐weighted (T2W) sequence. The other cohort of six cuprizone and four control mice were scanned using a dual‐echo sequence for T2‐mapping and a diffusion‐weighted sequence with two orthogonal diffusion encoding directions to calculate water diffusivities parallel and perpendicular to the CC fiber (apparent diffusion coefficients [ADC]∥ and ADC⟂). After the mice were killed, the rostral‐caudal pattern of CC demyelination and other pathologies were examined using Luxol Fast Blue, neurofilament staining, and immunohistochemistry for microglia and were correlated with MRI.ResultsIn contrast to control mice, T2W imaging (T2WI) hyperintensity, reduced ADC∥, and elevated ADC⟂ were detected in the CC of cuprizone‐fed mice, particularly in the caudal segment. The T2 value was increased in the entire CC. Marked demyelination, as well as axonal injury, microglia accumulation, and cellular infiltration were found in the caudal section of the cuprizone mouse CC. The rostral‐caudal pattern of abnormalities within the CC in MRI measurements correlated well with histopathological findings.ConclusionNoninvasive MRI using quantitative T2 and ADC mapping accurately characterized the rostral‐caudal pattern of CC demyelination and other pathologies in cuprizone challenged mice, and thus could provide an effective way to assess the structural response to experimental therapeutics being designed for the treatment of MS. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Different strategies for MRI measurements of renal cortical volume
Authors: Karstoft Kristian , Lødrup Anders B. , Dissing Thomas H. , Sørensen Thomas S. , Nyengaard Jens R. , Pedersen Michael 
Published: October 2007

AbstractPurposeFirst, to measure renal cortical volume (Vc) using different MRI methods combined with a semiautomatic segmentation method. Second, to compare MRI measurements of Vc using the semiautomatic segmentation method with a manual segmentation method. Third, to evaluate the reproducibility of Vc measurements.Materials and MethodsA total of 22 pigs, 13 with healthy kidneys and nine with diseased kidneys, underwent MRI with two non‐contrast‐agent methods (MRI100×900 and MRI300×1100) and one contrast‐agent method (MRIGd). For each of these methods, Vc was estimated using semiautomatic (Vc100×900, Vc300×1100, and VcGd), as well as manual (VcMANUAL) segmentation. Reference volumes were estimated by stereological means (VcSTEREOLOGY). MRI‐derived volumes were compared with reference volumes using a two‐tailed paired t‐test, and variances between methods were visualized with Bland Altman plots. Reproducibilities were analyzed using covariance analysis.ResultsNeither measurements of Vc100×900, Vc300×1100, nor VcGd differed markedly from VcSTEREOLOGY using semiautomatic segmentation. Vc was comparable when semiautomatic and manual segmentations were performed at the same scan. Reproducibility of MRI estimated Vc values offered intra‐ and interindividual differences <5%.ConclusionVc can in both healthy and diseased kidneys be measured accurately with MRI using both semiautomatic and manual segmentation, and measurements can be obtained with a high reproducibility. Measurements of Vc100×900 may in the future become suitable in patients with chronic renal failure. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Direct comparison of myocardial perfusion cardiovascular magnetic resonance sequences with parallel acquisition
Authors: Lyne Jonathan C. , Gatehouse Peter D. , Assomull Ravi G. , Smith Gillian C. , Kellman Peter , Firmin David N. , Pennell Dudley J. 
Published: October 2007

AbstractPurposeTo directly compare the three main myocardial perfusion cardiovascular magnetic resonance (CMR) sequences incorporating parallel acquisition methods.Materials and MethodsIn 15 subjects (12 men, 57 ± 15.7 years) referred for diagnostic coronary angiography, we acquired first‐pass perfusion images (0.1 mmol/kg gadolinium‐DTPA) at rest and during adenosine (140 μg/kg/min) on three separate occasions using three sequences incorporating parallel acquisition methods and approximately equivalent spatiotemporal resolution: hybrid echo planar imaging (hEPI), steady‐state free precession (SSFP), and gradient echo imaging (GRE). We calculated the contrast‐to‐noise ratio (CNR) of each scan and blinded observers scored the presence and severity of artifacts (1, worst to 4, best), diagnostic confidence (0, low to 2, high), transmurality, area, and epicardial vessel territory of perfusion defects.ResultsCNR was greatest with SSFP and least with hEPI (13.15 vs 7.85 P < 0.001). The most artifacts were recorded with SSFP and least with hEPI (2.00 vs 3.03 P < 0.001). Observers were significantly more confident in reporting hEPI images (1.6 hEPI vs 0.9 SSFP, P < 0.001). Results for GRE were intermediate for all assessments.ConclusionThe hEPI sequence scored best for diagnostic performance despite the SSFP sequence having greater CNR. This trial favors hEPI for clinical myocardial perfusion CMR and suggests CNR should not be the sole criterion used to gauge the best candidate sequence. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Magnetic resonance imaging assessment of a convective therapy delivery paradigm in a canine prostate model
Authors: Shetty Anil M. , Stafford R. Jason , Elliott Andrew M. , Kassouf Wassim , Brown Gordon A. , Stephens L. Clifton , Tinkey Peggy T. , Bidaut Luc , Pisters Louis L. , Hazle John D. 
Published: October 2007

AbstractPurposeTo quantitatively investigate the feasibility of MRI as a tool for assessing the spatial distribution of a convectively delivered agent using a canine prostate model.Materials and MethodsCanine prostates (ex vivo, n = 3; in vivo, n = 12) were injected under several injection paradigms with a solution of gadolinium‐DTPA for MR contrast and methylene blue as a grossly visible surrogate drug marker. Ex vivo and in vivo distributions were assessed at 1.5T and quantitatively compared.ResultsMeasured distributions using MRI and methylene blue pathology photographs were analyzed using a Bland–Altman method. The fractional percentage volume covered (Vfrac) compared the measurements grossly: Pearson's correlation coefficients were R = 0.99 for ex vivo and R = 0.77 for in vivo (P < 0.05). The fractional percentage of area covered (Afrac) demonstrated the high degree of spatial correlation between individual slices: R = 0.93 for ex vivo and R = 0.98 for in vivo (P < 0.05). There was no statistically observable bias in scale or offset between the measurements.ConclusionMeasured distributions using MRI and pathology were highly correlated and unbiased, indicating the potential of MRI as a tool for quantitative assessment of interstitial delivery of injected therapies in vivo. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Pancreatic cancer: Correlation of MR findings, clinical features, and tumor grade
Authors: Elias Jorge , Semelka Richard C. , Altun Ersan , Tsurusaki Masakatsu , Pamuklar Ertan , Zapparoli Mauricio , Voultsinos Vasileios , Armao Diane M. , Rubinas Tara 
Published: October 2007

AbstractPurposeTo assess the frequency of occurrence of poorly‐marginated and focally‐defined pancreatic ductal adenocarcinoma by MRI and to determine whether these appearances correlate with clinical features and histopathological grade.Materials and MethodsInstitutional review board with waiver of informed consent was obtained for this HIPAA compliant study. A total of 33 patients (16 female, 17 male, mean age = 63.5 ± 12.8, ranging from 41 to 80 years) with histopathologically‐proven pancreatic ductal adenocarcinoma who underwent MR examination between August 2000 and February 2005 were retrospectively evaluated. Clinical data and histopathological tumoral grade were obtained from clinical charts; nine of 33 patients were excluded of the histopathological evaluation since their diagnosis was performed by fine needle aspiration biopsy and it was not possible to obtain the histopathological grade. Two radiologists reviewed all cases independently to identify whether cancers were poorly‐marginated or focally‐defined. Agreement between radiologists was assessed using the kappa coefficient. The overall correlation between imaging findings, clinical features, and histopathological grade was assessed with contingency tables using the Fisher's exact test.ResultsOf the 33 patients, nine (27.2%) were classified as poorly‐marginated and 24 (72.8%) as focally‐defined. Agreement between the two reviewers was excellent (k = 0.92, 95% confidence interval (CI) = 0.78–1.0). Poorly‐marginated cancers exhibited well‐ to moderately‐differentiated histopathology in 71.4% of cases, while focally‐defined cancers had well‐ to moderately‐differentiated histopathology in 17.6% of cases, P = 0.02.ConclusionA poorly‐marginated appearance of pancreatic ductal carcinoma on MRI is not uncommon. These cancers exhibited statistically significant moderate‐ to well‐differentiated histopathology compared to focally‐defined cancers. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Robust dynamic susceptibility contrast MR perfusion using 4D nonlinear noise filters
Authors: Kosior Jayme Cameron , Kosior Robert Karl , Frayne Richard 
Published: October 2007

AbstractPurposeTo investigate if 4D (simultaneous space and time) nonlinear filtering techniques can produce more robust cerebral blood flow (CBF) estimates by reducing noise in acquired dynamic susceptibility contrast (DSC) MR perfusion data.Materials and MethodsA digital anthropomorphic brain perfusion phantom was constructed to analyze filter performance by: 1) deriving anthropomorphic tissue volume fractions from a human subject and 2) simulating DSC‐MR perfusion signals for voxels with mixed tissue for various signal‐to‐noise ratios (SNRs). DSC‐MR data for 11 acute ischemic stroke patients were also acquired at 3T. CBF maps cross‐calibrated so that normal white matter CBF was 22 mL/minute/100 g were produced from DSC‐MR data without filtering and from 4D‐Gaussian and 4D‐bilateral noise‐filtered DSC‐MR data.ResultsThe nonlinear 4D‐bilateral filter yielded the lowest CBF root‐mean square error (RMSE) in the phantom experiments with noise (average RMSE across all tissues regions for no filtering, 4D‐Gaussian, and 4D‐bilateral was 5.3 mL/minute/100 g, 6.2 mL/minute/100 g, and 4.0 mL/minute/100 g, respectively) and had the best image quality in both the phantom and patient data.ConclusionNonlinear 4D noise filters are better suited to the 4D nature of DSC‐MR data. Linear spatial filters are not appropriate and can produce larger CBF errors than without filtering. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.