bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oscillatory response function: Towards a parametric model of rhythmic brain activity
Authors: Ramkumar Pavan , Parkkonen Lauri , Hari Riitta 
Published: December 2009

AbstractRhythmic brain activity, measured by magnetoencephalography (MEG), is modulated during stimulation and task performance. Here, we introduce an oscillatory response function (ORF) to predict the dynamic suppression–rebound modulation of brain rhythms during a stimulus sequence. We derived a class of parametric models for the ORF in a generalized convolution framework. The model parameters were estimated from MEG data acquired from 10 subjects during bilateral tactile stimulation of fingers (stimulus rates of 4 Hz and 10 Hz in blocks of 0.5, 1, 2, and 4 s). The envelopes of the 17–23 Hz rhythmic activity, computed for sensors above the rolandic region, correlated 25%–43% better with the envelopes predicted by the models than by the stimulus time course (boxcar). A linear model with separate convolution kernels for onset and offset responses gave the best prediction. We studied the generalizability of this model with data from 5 different subjects during a separate bilateral tactile sequence by first identifying neural sources of the 17–23 Hz activity using cortically constrained minimum norm estimates. Both the model and the boxcar predicted strongest modulation in the primary motor cortex. For short‐duration stimulus blocks, the model predicted the envelope of the cortical currents 20% better than the boxcar did. These results suggest that ORFs could concisely describe brain rhythms during different stimuli, tasks, and pathologies. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Modulation of hyaluronan production by CD44 positive glioma cells
Authors: Wiranowska Marzenna , Ladd Sharron , Moscinski Lynn C. , Hill Bobbye , Haller Ed , Mikecz Katalin , Plaas Anna 
Published: December 2009

AbstractThis study examines the functional relationship between glioma cell production of hyaluronan (HA), known to play a role in glioma invasion, expression of its CD44 receptor, and glioma cell viability. Production of HA by CD44 positive mouse G26 and human U373 glioma cell lines was evaluated and compared to that of a CD44 positive mouse fibroblast‐like L929 cell line. We found that both G26 and U373 MG glioma cells, but not L929 fibroblast‐like cells, synthesized HA. The synthesis of HA by glioma cells was found during the proliferative phase as well as post‐confluency, as detected by fluorophore‐assisted carbohydrate electrophoresis. Eighty to ninety percent of the HA synthesized was secreted into the medium and 10–20% remained associated with the cells. To examine a possible mechanistic link between the CD44‐HA interaction and endogenous HA production, glioma cells were treated with either anti‐CD44 antibodies (clones KM201 or IM7) or HA oligosaccharides (hexamer oligoHA‐6 or decamer oligoHA‐10). We found that oligoHA‐10, which was previously shown to compete effectively with the CD44‐HA interaction, enhanced glioma HA synthesis by approximately 1.5‐fold, without affecting cell viability. IM7 treatment of human U373 glioma cells resulted in over 50% decrease of HA production, which was associated with changes in cell size and apoptosis. Taken together, these data show that CD44 specific ligands, such as the IM7 antibody or oligoHA‐10 could down‐regulate or up‐regulate glioma HA production, respectively. Our results suggest that interference with CD44/HA may lead to the discovery and development of new treatment modalities for glioma.
Loss of imprinting and marked gene elevation are 2 forms of aberrant IGF2 expression in colorectal cancer
Authors: Cheng Yu‐Wei , Idrees Kamran , Shattock Richard , Khan Sajid A. , Zeng Zhaoshi , Brennan Cameron W. , Paty Philip , Barany Francis 
Published: December 2009

AbstractLoss of imprinting (LOI) of insulin‐like growth factor 2 (IGF2) is a common event in many cancers and typically activates the maternally silenced allele. The resulting biallelic IGF2 expression correlates strongly with the hypomethylation of a differentially methylated region (DMR) near its promoter. It has also been shown that IGF2 undergoes overexpression in human malignancies; nevertheless, this phenomenon and its link to aberrant DMR methylation have not been reported in colorectal cancer (CRC). The aim of this study was to determine the relationship between IGF2 LOI, overexpression and DMR hypomethylation in CRC. By analyzing IGF2 and H19 methylation in 97 primary CRC and 64 matched normal colorectal tissues, we have shown a significant correlation between IGF2 LOI and DMR hypomethylation of IGF2 and H19. Additionally, when analyzing Affymetrix expression data of 167 primary CRC tumors and 32 normal tissues, 15% of tumors showed marked IGF2 elevation. We further investigated if substantially elevated IGF2 levels were linked to IGF2 or H19 hypomethylation, but found no significant correlation. However, we demonstrated that noticeable IGF2 overexpression, rather than LOI, negatively correlated with CRC microsatellite instability. These observations indicate that IGF2 expression, particularly when transcribed at significantly high levels, is a result of mechanisms unrelated to LOI. Our results suggest that IGF2 participates in CRC tumorigenesis through 2 different forms of aberrant gene expression.
Chemo‐radiotherapy for advanced non‐small cell lung cancer: concurrent or sequential? It's no longer the question: a systematic review
Authors: Liang Hui‐Ying , Zhou Hao , Li Xue‐Lian , Yin Zhi‐Hua , Guan Peng , Zhou Bao‐Sen 
Published: December 2009

AbstractThere has been conflicting evidence concerning the best sequence of radiotherapy (RT) and chemotherapy (CT) for advanced non‐small‐cell‐lung‐cancer (NSCLC). To investigate whether current clinical trials can clarify this schedule and offer further bases for clinical decision making, we performed a systematic review of 11 trials (2,043 patients; concurrent–1,019, sequential–1,024) that compared concurrent RT‐CT with sequential arm in advanced NSCLC patients. Primary end point was overall survival (OS). Pooled median ratios (MRs) and progression‐free‐survival ratios (FRs) for median survival and progression‐free survival (PFS) were calculated using the weighted sum of the log ratio of MR and FR of individual study. Pooled odds ratios (ORs) for the objective response rate, relapse control rate, and toxic events were calculated using the Mantel‐Haenszel estimate. Results confirmed that concurrent RT‐CT determined a statistically significant increase in median survival time (16.3 vs. 13.9 months; MR = 1.17,95%CI:1.09–1.26), response rate (64.0% vs. 56.3%; OR = 1.38,95%CI:1.10–1.72), and tumor‐relapse control (OR = 0.82,95%CI:0.69–0.97), though at the expense of increased hematological toxicity (neutropenia and thrombocytopenia) and non‐hematological toxicity (nausea/vomiting, stomatitis, and esophagitis). Similar results were obtained from the sensitivity analysis of all Phase‐III/trials designed to evaluate the primary end point of OS. Subgroup analysis revealed that concurrent strategy was mainly associated with improved loco‐regional control (OR = 0.68,95%CI:0.52–0.87). However, no difference in PFS is shown. While careful interpretation of our conclusions is required because of potential bias, the present study, to some extent, exhibits the superiority of the concurrent arm over the sequential in the treatment of advanced NSCLC. Further improvements will be obtained by optimizing the conditions for a concurrent regimen.
Cyclin B1 is a prognostic proliferation marker with a high reproducibility in a population‐based lymph node negative breast cancer cohort
Authors: Niméus‐Malmström E. , Koliadi A. , Ahlin C. , Holmqvist M. , Holmberg L. , Amini R.‐M. , Jirström K. , Wärnberg F. , Blomqvist C. , Fernö M. , Fjällskog M.‐L. 
Published: December 2009

AbstractA large proportion of women with lymph node negative breast cancer do not benefit from chemotherapy. Proliferation markers have been shown to recognize patients at high risk for recurrence. The Ki67 protein has recently been included in the St Gallen guidelines. The authors investigated the prognostic importance of cyclin B1 in node negative breast cancer and included a study of reproducibility. In a population‐based case‐control study, 190 women who died from breast cancer were defined as cases and 190 women alive at the time for the corresponding case's death were defined as controls. Inclusion criteria were tumor size ≤50 mm, no lymph node metastases, and no adjuvant chemotherapy. Tumor tissue was immunostained for cyclin B1. Two investigators (EN‐M and AK) evaluated the staining independently by counting approximately 100, 200, 500, and 1000 cells. Cyclin B1 was statistically significantly associated to breast cancer death, in both uni‐ and multivariate analyses (adjusted for tumor size, age, and endocrine therapy), with odds ratios 2–3 for both investigators. The agreement between the two investigators was good to very good, regardless of the number of counted cells (kappa values between 0.74 and 0.82). Cyclin B1 is a prognostic factor for breast cancer death in a population‐based node negative patient cohort which can identify high‐risk patients with a good to very good reproducibility.
Nanotechnology‐based molecular photoacoustic and photothermal flow cytometry platform for in‐vivo detection and killing of circulating cancer stem cells
Authors: Galanzha Ekaterina I. , Kim Jin‐Woo , Zharov Vladimir P. 
Published: December 2009

AbstractIn‐vivo multicolor photoacoustic (PA) flow cytometry for ultrasensitive molecular detection of the CD44+ circulating tumor cells (CTCs) is demonstrated on a mouse model of human breast cancer. Targeting of CTCs with stem‐like phenotype, which are naturally shed from parent tumors, was performed with functionalized gold and magnetic nanoparticles. Results in vivo were verified in vitro with a multifunctional microscope, which integrates PA, photothermal (PT), fluorescent and transmission modules. Magnet‐induced clustering of magnetic nanoparticles in individual cells significantly amplified PT and PA signals. The novel noninvasive platform, which integrates multispectral PA detection and PT therapy with a potential for multiplex targeting of many cancer biomarkers using multicolor nanoparticles, may prospectively solve grand challenges in cancer research for diagnosis and purging of undetectable yet tumor‐initiating cells in circulation before they form metastasis. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An injection molding process for manufacturing highly porous and interconnected biodegradable polymer matrices for use as tissue engineering scaffolds
Authors: Kramschuster Adam , Turng Lih‐Sheng 
Published: December 2009

AbstractIn this research, injection molding was combined with a novel material combination, supercritical fluid processing, and particulate leaching techniques to produce highly porous and interconnected structures that have the potential to act as scaffolds for tissue engineering applications. The foamed structures, molded with polylactide (PLA) and polyvinyl alcohol (PVOH) with salt as the particulate, were processed without the aid of organic solvents, which can be detrimental to tissue growth. The pore size in the scaffolds is controlled by salt particulates and interconnectivity is achieved by the co‐continuous blending morphology of biodegradable PLA matrix with water‐soluble PVOH. Carbon dioxide (CO2) at the supercritical state is used to serve as a plasticizer, thereby imparting moldability of blends even with an ultra high salt particulate content, and allows the use of low processing temperatures, which are desirable for temperature‐sensitive biodegradable polymers. Interconnected pores of ∼200 μm in diameter and porosities of ∼75% are reported and discussed. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Evaluation of microhardness, surface roughness, and wear behavior of different types of resin composites polymerized with two different light sources
Authors: Topcu Fulya Toksoy , Erdemir Ugur , Sahinkesen Gunes , Yildiz Esra , Uslan Ibrahim , Acikel Cengizhan 
Published: December 2009

AbstractThe microhardness, surface roughness and wear resistance of different types of resin composites, polymerized by a Quartz Tungsten Halogen (QTH) or Light Emitting Diode (LED) light curing units (LCU) were evaluated in this in vitro study. Cylindrical blocks were prepared from composites (8 mm in diameter, and 2 mm in thickness) and polymerized by a LED or a QTH LCU. Vickers hardness was measured on the top and bottom surfaces of the specimens. Surface roughness was measured with a surface profilometer on the top of the specimens. For the wear test, specimens were tested in a conventional pin‐on‐disc tribology machine under 15 N loads. The statistical analyses were performed by one‐way analysis of variance (ANOVA) and t‐tests, including the Bonferroni correction. Nanocomposite material Clearfil Majesty™ Posterior showed the highest hardness values in all polymerization types at the top and bottom surfaces (p < 0.05). Microhybrid Clearfil™ APX and hybrid Quixfil™ composites demonstrated the greatest surface roughness. Wear resistance of Clearfil Majesty™ Posterior was found to be the highest among the other tested resin composites. The results indicated that Clearfil Majesty™ Posterior demonstrated higher microhardness, less surface roughness, and higher wear resistance when compared with the other tested materials for both polymerization types. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Modification of the diphenylamine assay for cell quantification in three‐dimensional biodegradable polymeric scaffolds
Authors: Pham Edward A. , Ho Won Jin , Kamei Daniel T. , Wu Benjamin M. 
Published: December 2009

AbstractAs three‐dimensional (3D) cell culture systems gain popularity in biomedical research, reliable assays for cell proliferation within 3D matrices become more important. Although many cell quantification techniques have been established for cells cultured on nondegradable plastic culture dishes and cells suspended in media, it is becoming increasingly clear that cell quantification after prolonged culture in 3D polymeric scaffolds imposes unique challenges because the added presence of polymeric materials may contribute to background signal via various mechanisms including autofluorescence, diffusion gradients, and sequestering effects. Thus, additional steps are required to ensure complete isolation of cells from the 3D scaffold. The diphenylamine assay isolates cellular DNA, degrades the polymeric matrix materials, and reacts with the DNA to yield a colorimetric response. Thus, we report here a practical modification of the diphenylamine assay and show that the assay quantifies cells in 3D polyester scaffolds reliably and reproducibly as long as the necessary amount of the acidic working reagent is present. Our study also demonstrates that the sensitivity of the assay can be optimized by controlling the dimensions of the sampling volume. Overall, the DPA assay offers an attractive solution for challenges associated with 3D cell quantification. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Macro‐alignment of electrospun fibers for vascular tissue engineering
Authors: Zhu Yabin , Cao Ye , Pan Jin , Liu Yuxin 
Published: December 2009

AbstractDesign of polymeric scaffolds with specific physical and biological properties is a key objective of tissue engineering research. Electrospinning generates loosely connected 3D porous mats simulating extra cellular matrix structure and therefore makes itself an excellent candidate for application in tissue engineering. Besides a high voltage generator and syringe pump, our electrospinning system was improved to add a programmable central controller which monitors system operation. The nozzles connected with syringe pump via silicon rubber tubing can move linearly with a step size of 0.1 μm or above while the mandrel collector rotates at a speed from 400 to 3000 revolutions per minute (rpm). Using this system, porous fiber sheets with fiber diameters ranging from 100 nm to several micrometers or meshes of macroscopically aligned fibers with diameter of ∼10 μm have been fabricated under proper processing conditions. After biocompatible fibrin coating, oriented polycaprolactone (PCL) fibers were found to enhance the shifting of human umbilical artery smooth muscle cells from synthetic to contractile phenotype, and to maintain biological function of human umbilical vein endothelial cells. We believe that our electrospinning system will facilitate scaffold fabrication for vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Carboxymethylation of the fibrillar collagen with respect to formation of hydroxyapatite
Authors: Ehrlich Hermann , Hanke Thomas , Simon Paul , Born René , Fischer Christiane , Frolov Andrej , Langrock Tobias , Hoffmann Ralf , Schwarzenbolz Uwe , Henle Thomas , Bazhenov Vasily V. , Worch Hartmut 
Published: December 2009

AbstractControl over crystal growth by acidic matrix macromolecules is an important process in the formation of many mineralized tissues. Highly acidic macromolecules are postulated intermediates in tissue mineralization, because they sequester many calcium ions and occur in high concentrations at mineralizing foci in distantly related organisms. A prerequisite for biomineralization is the ability of cations like calcium to bind to proteins and to result in concert with appropriate anions like phosphates or carbonates in composite materials with bone‐like properties. For this mineralization process the proteins have to be modified with respect to acidification. In this study we modified the protein collagen by carboxymethylation using glucuronic acid. Our experiments showed unambigously, that Nε‐carboxymethyllysine is the major product of the in vitro nonenzymatic glycation reaction between glucuronic acid and collagen. We hypothesized that the function of biomimetically carboxymethylated collagen is to increase the local concentration of corresponding ions so that a critical nucleus of ions can be formed, leading to the formation of the mineral. Thus, the self‐organization of HAP nanocrystals on and within collagen fibrils was intensified by carboxymethylation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Diffusion bonding of mismatch dental alloys
Authors: Liu Honghua , Ni Jiahua , Wu Luhai , He Guo 
Published: December 2009

AbstractThe diffusion bonding of Ti‐6Al‐4V and Co‐Cr‐Mo dental alloys has been investigated in terms of the atoms diffusion, the microstructure evolution, and the bonding strength. The bonding performance reveals asymmetry diffusion profiles for both the Co and Cr in Ti‐6Al‐4V and the Ti in Co‐Cr‐Mo alloy. Their diffusion coefficients (Arrhenius relations) have been established based on the experiments. Co and Cr diffusion into Ti‐6Al‐4V leads to alpha → beta transformation and the intermetallics‐formation. Maximum bonding strength occurs at about 840°C. The bonding joint fails under the shear stress in the Ti‐6Al‐4V side near the bonding interface in brittle manner. The intermetallics in the diffusion layer together with the unbonded areas and other flaws in the bonding interface are responsible for the shear brittle fracture, which also weaken the bonding strength. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Expression analysis of epithelial cadherin and related proteins in IBH‐6 and IBH‐4 human breast cancer cell lines
Authors: Lapyckyj Lara , Castillo Lilian Fedra , Matos María Laura , Gabrielli Nieves María , Lüthy Isabel Alicia , Vazquez‐Levin Mónica Hebe 
Published: December 2009

AbstractEpithelial cadherin (E‐cadherin) is a 120 kDa cell–cell adhesion molecule involved in the establishment of epithelial adherens junctions. It is connected to the actin cytoskeleton by adaptor proteins such as β‐catenin. Loss of E‐cadherin expression/function has been related to tumor progression and metastasis. Several molecules associated with down‐regulation of E‐cadherin have been described, within them neural cadherin, Twist and dysadherin. Human breast cancer cell lines IBH‐6 and IBH‐4 were developed from ductal primary tumors and show characteristic features of malignant epithelial cells. In this study expression of E‐cadherin and related proteins in IBH‐6 and IBH‐4 cell lines was evaluated. In IBH‐6 and IBH‐4 cell extracts, only an 89 kDa E‐cadherin form (Ecad89) was detected, which is truncated at the C‐terminus and is present at low levels. Moreover, no accumulation of the 86 kDa E‐cadherin ectodomain and of the 38 kDa CTF1 fragment was observed. IBH‐6 and IBH‐4 cells showed an intracellular scattered E‐cadherin localization. β‐catenin accompanied E‐cadherin localization, and actin stress fibers were identified in both cell types. E‐cadherin mRNA levels were remarkably low in IBH‐6 and IBH‐4 cells. The E‐cadherin mRNA and genomic sequence encoding exons 14–16 could not be amplified in either cell line. Neither the mRNA nor the protein of neural cadherin and dysadherin were detected. Up‐regulation of Twist mRNA was found in both cell lines. In conclusion, IBH‐6 and IBH‐4 breast cancer cells show down‐regulation of E‐cadherin expression with aberrant protein localization, and up‐regulation of Twist; these features can be related to their invasive/metastatic characteristics. J. Cell. Physiol. 222: 596–605, 2010. © 2009 Wiley‐Liss, Inc.
Inorganic polyphosphate inhibits an aspartic protease‐like activity in the eggs of Rhodnius prolixus (Stahl) and impairs yolk mobilization in vitro
Authors: Gomes F.M. , Oliveira D.M.P. , Motta L.S. , Ramos I.B. , Miranda K.M. , Machado E.A. 
Published: December 2009

AbstractInorganic polyphosphate (poly P) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. In the egg yolk granules of Rhodnius prolixus, a cathepsin D is the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. In this study, we showed a possible role of poly P stored inside yolk granules on the inhibition of cathepsin D and arrest of yolk mobilization during early embryogenesis of these insects. Enzymatic assays detected poly P stores inside the eggs of R. prolixus. We observed that micromolar poly P concentrations inhibited cathepsin D proteolytic activity using both synthetic peptides and homogenates of egg yolk as substrates. Poly P was a substrate for Rhodnius acid phosphatase and also a strong competitive inhibitor of a pNPPase activity. Fusion events have been suggested as important steps towards acid phosphatase transport to yolk granules. We observed that poly P levels in those compartments were reduced after in vitro fusion assays and that the remaining poly P did not have the same cathepsin D inhibition activity after fusion. Our results are consistent with the hypothesis that poly P is a cathepsin D inhibitor and a substrate for acid phosphatase inside yolk granules. It is possible that, once activated, acid phosphatase might degrade poly P, allowing cathepsin D to initiate yolk proteolysis. We, therefore, suggest that degradation of poly P might represent a new step toward yolk mobilization during embryogenesis of R. prolixus. J. Cell. Physiol. 222: 606–611, 2010. © 2009 Wiley‐Liss, Inc.