bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequency resolved single‐shot MR imaging using stochastic k‐space trajectories
Authors: Scheffler Klaus , Hennig Jürgen 
Published: February 2011

AbstractA new single‐shot stochastic imaging technique with a random k‐space path that provides very selective filtering with respect to chemical shift or off‐resonance signals of the investigated tissue is proposed. It is demonstrated that in stochastic imaging only on‐resonance compartments are visible whereas frequency shifted compartments cancel to noise that is distributed over the whole image. This method can be used as a single‐shot chemical shift selective imaging technique and allows to calculate frequency resolved spectra for each spatial position of the image based on a single signal aquisition. The single‐shot stochastic imaging sequence makes high demands on the gradient system and the theoretical k‐space trajectory is distorted by imperfect gradient performance. Therefore an additional k‐space guided imaging technique that uses the true, measured k‐space trajectory to correct artifacts generated by eddy currents and delay times of the rapid switched gradients is presented. In vitro and in vivo measurements demonstrate the successful implementation of single‐shot stochastic imaging on a conventional MR scanner with unshielded gradient systems.
Intensity correction of phased‐array surface coil images
Authors: Murakami James W. , Hayes Cecil E. , Weinberger Ed 
Published: February 2011

AbstractPhased‐array coils distribute the high signal‐to‐noise ratio (SNR) performance of their small component surface coils over the larger area covered by the entire array. The inhomogeneous sensitivity profiles of the component surface coils result in images with very high signal near the phased‐array and decreased signal far from the array. This paper presents a postprocessing algorithm for correcting these coil‐related intensity variations. The algorithm's performance was evaluated by correcting images of volunteers acquired with several different receive‐only phased‐array surface coils.
Reproducibility of high spatial resolution proton magnetic resonance spectroscopic imaging in the human brain
Authors: Charles H. Cecil , Lazeyras François , Tupler Larry A. , Krishnan K. Ranga R. 
Published: February 2011

AbstractThe application of proton (1H) magnetic resonance spectroscopic imaging (MRSI) allows for noninvasive, localized analyses of brain biochemistry; however, minimal work has been devoted to the evaluation of 1H MRSI reproducibility. This study examined the reproducibility of 1H MRSI from five normal subjects on two occasions, separated by 10 days. Reproducibility of the MR signal was evaluated in the context of automated shimming, automated processing, and accurate subject repositioning. Reliability measures for physicochemical indices (choline moieties, creatine, N‐acetylaspartate, and myo‐inositol) were moderately concordant across repeat studies. Gain variation and repositioning results were excellent. It has been concluded that 1H MRSI reproducibility is adequate for serial studies of brain metabolism.
Expansion of the spectral bandwidth by spatial and chemical shift selective saturation in high‐speed magnetic resonance spectroscopic imaging
Authors: Hirata Satoshi , Bito Yoshitaka , Yamamoto Etsuji 
Published: February 2011

AbstractA new spectral bandwidth expansion technique for highspeed magnetic resonance spectroscopic imaging (MRSI) based on an echo‐planar technique is presented. This expansion can be achieved by spatial and chemical shift selective saturation without increasing the total measurement time. In addition, displacement along the slice‐select direction due to chemical‐shift differences between the measured compounds is also suppressed. Experimental results are shown using a phantom consisting of benzene and acetone. High spatial resolution (1 × 1 mm2) and wide spectral bandwidth (1.5–1.8 kHz; the effective spectral bandwidth has been doubled) are obtained without the displacement along the slice‐select direction.
Characterization of the cerebral distribution of general anesthetics in vivo by two‐dimensional 19F chemical shift imaging
Authors: Venkatasubramanian Palamadai N. , Shen Ying J. , Wyrwicz Alice M. 
Published: February 2011

AbstractThe distribution of two fluorinated anesthetics, halothane and isoflurane, in rabbit brain was mapped during the course of their uptake using 19F NMR chemical shift imaging techniques. Use of a short phase‐encoding time and free induction decay acquisition minimized T2‐related signal losses in two‐dimensional chemical shift imaging. Localization of the brain and exclusion of surrounding tissues was achieved by the use of a surface coil. The spatial distribution of halothane and isoflurane in the brain was nonuniform and both anesthetics were detected predominantly in the cerebral cortex. During the early stages of uptake, anesthetic concentration in the brain was extremely low, but it continued to increase for several hours with sustained anesthetic delivery. Time‐dependent variations in anesthetic concentration were observed in different brain regions.
Assessment of the effect of haematocrit‐dependent arterial input functions on the accuracy of pharmacokinetic parameters in dynamic contrast‐enhanced MRI
Authors: Just Nathalie , Koh Dow‐Mu , D'Arcy James , Collins David J. , Leach Martin O. 
Published: February 2011

AbstractThe detection and prognosis of prostate cancer in its early stages are critically important. It is therefore essential to improve the existing dynamic contrast‐enhanced MRI (DCE MRI) techniques commonly used for the assessment of the tumour vascular environment. The goal of this study was to describe a method for the estimation of the arterial input function (AIF) in DCE MRI by measuring R2* values in the femoral artery of patients with early‐stage prostate cancer. The calculation of contrast agent concentrations was based on calibration curves determined in whole blood samples for a range of normal haematocrit (HCT) values (HCT = 0.35–0.525). Individual AIFs corrected for HCT were compared with individual AIFs calibrated with a mean whole blood [R2*–Gd‐DTPA‐BMA] [Gd‐DTPA‐BMA, gadolinium diethylenetriaminepentaacetate‐bis(methylamide) (gadodiamide)] curve at an assumed HCT = 0.44, as well as a population AIF at an assumed HCT = 0.45. The area under the curve of the first‐pass bolus ranged between 0.6 min mM at HCT = 0.53 and 1.3 min mM at HCT = 0.39. Significant differences in magnitude at peak contrast agent concentrations (HCT = 0.36, [Gd‐DTPA‐BMA]max = 9 ± 0.4 mM; HCT = 0.46, [Gd‐DTPA‐BMA]max = 4.0 ± 0.2 mM) were found. Using model‐based simulations, the accuracy of the kinetic parameters estimated using individual AIFs corrected for HCT demonstrated that, for the use of individual calibration curves with HCT values differing by more than 10%, Ktrans and kep values were largely underestimated (up to 60% difference for Ktrans). Moreover, blood volume estimates were severely underestimated. Estimates of kinetic parameters in early‐stage prostate cancer patients demonstrated that the efflux rate constant (kep) was influenced significantly by the definition of AIF. Regardless of whether an individually calibrated AIF or a population AIF (average of all individually calibrated AIFs) was used, pixel‐by‐pixel mapping of kep and vb in the prostate gland appeared to be more sensitive than with the usual biexponential approach. Copyright © 2011 John Wiley & Sons, Ltd.
Reproducibility of prefrontal γ‐aminobutyric acid measurements with J‐edited spectroscopy
Authors: Geramita Matthew , van der Veen Jan Willem , Barnett Alan S. , Savostyanova Antonina A. , Shen Jun , Weinberger Daniel R. , Marenco Stefano 
Published: February 2011

Abstractγ‐Aminobutyric acid (GABA) is the chief inhibitory neurotransmitter of the human brain, and GABA‐ergic dysfunction has been implicated in a variety of neuropsychiatric disorders. Recent MRS techniques have allowed the quantification of GABA concentrations in vivo, and could therefore provide biologically relevant information. Few reports have formally characterized the reproducibility of these techniques, and differences in field strength, acquisition and processing parameters may result in large differences in measured GABA values. Here, we used a J‐edited, single‐voxel spectroscopy method of measurement of GABA + macromolecules (GABA + ) in the anterior cingulate cortex (ACC) and right frontal white matter (rFWM) at 3 T. We measured the coefficient of variation within subjects (CVw) and intra‐class correlation coefficients on two repeated scans obtained from 10 healthy volunteers with processing procedures developed in‐house for the quantification of GABA + and other major metabolites. In addition, by segmenting the spectroscopic voxel into cerebrospinal fluid, gray matter and white matter, and employing a linear regression technique to extrapolate metabolite values to pure gray and white matter, we determined metabolite differences between gray and white matter in ACC and rFWM. CVw values for GABA + /creatine, GABA + /H2O, GABA + , creatine, partially co‐edited glutamate + glutamine (Glx)/creatine, partially co‐edited Glx and N‐acetylaspartic acid (NAA)/creatine were all below 12% in both ACC and rFWM. After extrapolation to pure gray and pure white matter, CVw values for all metabolites were below 16%. We found metabolite ratios between gray and white matter for GABA + /creatine, GABA + , creatine, partially co‐edited Glx and NAA/creatine to be 0.88 ± 0.21 (standard deviation), 1.52 ± 0.32, 1.77 ± 0.4, 2.69 ± 0.74 and 0.70 ± 0.05, respectively. This study validates a reproducible method for the quantification of brain metabolites, and provides information on gray/white matter differences that may be important in the interpretation of results in clinical populations. Published in 2011 by John Wiley & Sons, Ltd.
Uncertainty feature optimization: An implicit paradigm for problems with noisy data
Authors: Eggenberg Niklaus , Salani Matteo , Bierlaire Michel 
Published: February 2011

AbstractOptimization problems with noisy data solved using stochastic programming or robust optimization approaches require the explicit characterization of an uncertainty set U that models the nature of the noise. Such approaches depend on the modeling of the uncertainty set and suffer from an erroneous estimation of the noise.In this article, we introduce a framework that considers the uncertain data implicitly. We define the concept of Uncertainty Features (UF), which are problem‐specific structural properties of a solution. We show how to formulate an uncertain problem using the Uncertainty Feature Optimization (UFO) framework as a multi‐objective problem. We show that stochastic programming and robust optimization are particular cases of the UFO framework. We present computational results for the Multi‐Dimensional Knapsack Problem (MDKP) and discuss the application of the framework to the airline scheduling problem. © 2011 Wiley Periodicals, Inc. NETWORKS, 2011
Erythropoietin protects against apoptosis and increases expression of non‐neuronal cell markers in the hypoxia‐injured developing brain
Authors: Yamada Miko , Burke Christopher , Colditz Paul , Johnson David W , Gobe Glenda C 
Published: February 2011

AbstractErythropoietin (EPO) is a cytokine hormone with cytoprotective effects in many tissues including the brain. Although the benefits of administration of recombinant human EPO (rhEPO) for neonatal hypoxic brain injury have been demonstrated in neuronal tissue, the effect on non‐neuronal cell populations is unclear. We tested the hypothesis that rhEPO would not only protect neuronal cells but also glial cells at a stage of brain development where their maturation was particularly sensitive, and also protect the vasculature. This was evaluated in a rat model of hypoxic injury. 1000 IU/kg rhEPO was delivered intraperitoneally at the start of 4 h hypoxia or normoxia. Treatment groups of neonatal rats (day of birth, at least N = 10 per group) were as follows: normoxia; normoxia plus rhEPO; hypoxia (8% FiO2 delivered in temperature‐controlled chambers); and hypoxia plus rhEPO. Day of birth in rats is equivalent to human gestation of 28–32 weeks. The effects of rhEPO administration, especially to non‐neuronal cell populations, and the associated molecular pathways, were investigated. Apoptosis was increased with hypoxia and this was significantly reduced with rhEPO (p < 0.05). The neuronal marker, microtubule‐associated protein‐2, increased in expression (p < 0.05) when apoptosis was significantly reduced by rhEPO. In addition, compared with hypoxia alone, rhEPO‐treated hypoxia had the following significant protein expression increases (p < 0.05): the intermediate filament structural protein nestin; myelin basic protein (oligodendrocytes); and glial fibrillary acidic protein (astrocytes). In conclusion, rhEPO protects the developing brain via anti‐apoptotic mechanisms and promotes the health of non‐neuronal as well as neuronal cell populations at a time when loss of these cells would have long‐lasting effects on brain function. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Ewing sarcoma cells express RANKL and support osteoclastogenesis
Authors: Taylor Richard , Knowles Helen J , Athanasou Nicholas A 
Published: February 2011

AbstractEwing sarcoma (ES) is a primary malignant round cell tumour of bone characterized by rapid and extensive osteolysis. Cellular mechanisms underlying the rapid bone resorption in ES have not been characterized. Osteoclasts are marrow‐derived multinucleated cells that effect tumour osteolysis. The role of ES tumour cells in influencing osteoclast formation and/or directly contributing to the osteolysis in ES has not been determined. Using a tissue culture bioassay, we found that lacunar resorption is not carried out by (CD99+) ES tumour cells, but by (CD68+) macrophage/osteoclast‐like cells; this resorption occurred in the absence of the osteoclastogenic factor, receptor activator of nuclear factor κB ligand (RANKL). ES cell lines cultured directly on dentine slices did not resorb the mineral or organic components of the bone matrix. Immunohistochemistry of ES tissue microarrays, western blotting, and RT‐PCR studies showed that ES cells strongly expressed both RANKL and macrophage‐colony stimulating factor (M‐CSF), two major osteoclastogenic factors. When co‐cultured with human monocytes, ES cells induced the formation of TRAP+ osteoclastic cells. Conditioned medium from cultured ES cells did not result in osteoclast formation, indicating that cell–cell contact is required for ES‐induced osteoclastogenesis. Our findings indicate that ES cells do not resorb bone directly but that they may support osteoclast formation by a RANKL‐dependent mechanism. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Transforming growth factor‐beta type 1 receptor (ALK5) and Smad proteins mediate TIMP‐1 and collagen synthesis in experimental intestinal fibrosis
Authors: Medina Carlos , Santos‐Martinez Maria Jose , Santana Alfredo , Paz‐Cabrera Maria Cristina , Johnston Michael J , Mourelle Marisabel , Salas Antonio , Guarner Francisco 
Published: February 2011

AbstractTransforming growth factor β (TGF‐β) is known to play a key role in intestinal fibrosis; however, the underlying mechanisms are not well understood. TGF‐β signal transduction is through TGF‐β receptors, including the TGF‐β type 1 receptor. Most cell types contain a TGF‐β type 1 receptor form known as activin receptor‐like kinase 5 (ALK5), which propagates the signal to the nucleus through the phosphorylation of Smad2 and Smad3 proteins. Therefore, we assessed the effect of the disruption of TGF‐β/ALK5/Smad signalling by an ALK5 inhibitor (SD‐208) in two experimental animal models of intestinal fibrosis: anaerobic bacteria‐ and trinitrobenzensulphonic acid‐induced colitis. In addition, isolated myofibroblasts were pretreated with SD‐208 and exposed to recombinant TGF‐β1. Finally, myofibroblasts were transfected with ALK5, Smad2, and Smad3‐specific siRNA. Up‐regulation of ALK5 and TIMP‐1, phosphorylation of Smad2 and Smad3 proteins, and increased intestinal wall collagen deposition were found in both experimental animal models. These effects were decreased by SD‐208. TGF‐β1 treatment also induced phosphorylation of Smad2 and Smad3 and up‐regulation of ALK5 protein, TIMP‐1, and α2 type 1 collagen gene expression in isolated myofibroblasts. Again these effects were inhibited by SD‐208. Also, ALK5, Smad2, and Smad3 siRNA abolished the induction of TIMP‐1 and α2 type 1 collagen. Our findings provide evidence that the TGF‐β/ALK5/Smad pathway participates in the pathogenesis of experimental intestinal fibrosis. These data show promise for the development of an effective therapeutic intervention in this condition. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
FMNL2 is a positive regulator of cell motility and metastasis in colorectal carcinoma
Authors: Zhu Xi‐ling , Zeng Yuan‐feng , Guan Jian , Li Yu‐fa , Deng Yong‐jian , Bian Xiu‐wu , Ding Yan‐qing , Liang Li 
Published: February 2011

AbstractFMNL2 is a member of diaphanous‐related formins which act as effectors of Rho family GTPases and control the actin‐dependent processes such as cell motility or invasion. We previously found that FMNL2 overexpression in metastatic cell lines and tissues of colorectal carcinoma is associated with more aggressive tumour behaviour. Here we used gain‐of‐function and loss‐of‐function approaches to investigate the effects of FMNL2 on colorectal carcinoma in vitro and in vivo. Forced expression of FMNL2 caused a significant increase in tumour cell proliferation, motility, invasion in vitro, and metastasis in vivo, whereas FMNL2 depletion showed opposite effects. We examined gene expression profiles following knockdown of FMNL2 in SW480/M5 cells. Expression of 323 genes was up‐regulated by more than two‐fold, whereas 222 genes were down‐regulated by more than two‐fold in FMNL2‐depleting SW480/M5 cells. Gene ontology analysis showed that most of genes belong to functional categories such as cell cycle, cytoskeleton, transcription factor, and G‐protein modulator. Pathway analysis revealed that cytoskeletal regulation by the Rho GTPase pathway, the Wnt pathway, the G‐protein pathway, and the P53 pathway were affected by FMNL2. Many of these genes are in functional networks associated with cell proliferation, metastasis, Wnt or the Rho signalling pathway involved in the regulation of FMNL2. The expression of five differentially expressed genes including CXXC4, CD200, VAV1, CSF1, and EPHA2 was validated by real‐time PCR and western blot analysis. Thus, FMNL2 is a positive regulator of cell motility, invasion, and metastasis of colorectal carcinoma. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Predictors of independent living status in adult survivors of childhood cancer: A report from the Childhood Cancer Survivor Study
Authors: Kunin‐Batson Alicia , Kadan‐Lottick Nina , Zhu Liang , Cox Cheryl , Bordes‐Edgar Veronica , Srivastava Deo Kumar , Zeltzer Lonnie , Robison Leslie L. , Krull Kevin R. 
Published: February 2011

AbstractBackgroundAdult survivors of childhood cancer and their siblings are compared on one of the most salient developmental milestones of adulthood, the ability to live independently.ProcedureAdult survivors of childhood cancers (n = 6,047) and siblings (n = 2,326), all 25 years of age and older, completed a long‐term follow‐up questionnaire that assessed adaptive, neurocognitive, and psychological functioning, as well as demographic and health status. Multivariable logistic regression analyses and structural equation modeling (SEM) were used to identify predictors of independent living.ResultsCompared to siblings (n = 206, 8.7%), survivors (n = 1063; 17.7%) were more than twice as likely to live dependently (OR 2.07; 95% confidence interval [CI] 1.77–2.42). Survivors diagnosed with CNS tumors (OR 0.13, 95% CI 0.10–0.18) or leukemia (OR 0.29, 95% CI 0.23–0.27) were significantly less likely to live independently compared to those diagnosed with Hodgkin lymphoma. Other risk factors for reduced independent living included cranial radiation (≤24 Gy OR 0.76, 95% CI 0.62–0.93; >24 Gy OR 0.31, 95% CI 0.24–0.41), use of neuroleptic, anticonvulsant, or psychostimulant medication (OR 0.32, 95% CI 0.24–0.43), attention and processing speed problems (OR 0.58, 95% CI 0.47–0.71), poor physical functioning (OR 0.49, 95% CI 0.38–0.63), depression (OR 0.68, 95% CI 0.53–0.88), and racial/ethnic minority status (OR 0.39, 95% CI 0.30–0.51). SEM demonstrated that neurocognitive functioning had both direct effects on independent living status, and indirect effects through use of neurologically directed medication, depression, and poor mental health.ConclusionAdult survivors of childhood cancer who experience neurocognitive, psychological, or physical late effects are less likely to live independently as adults. Pediatr Blood Cancer 2011; 57: 1197–1203. © 2011 Wiley Periodicals, Inc.
Platelet disorders in children: A diagnostic approach
Authors: Israels Sara J. , Kahr Walter H.A. , Blanchette Victor S. , Luban Naomi L.C. , Rivard Georges E. , Rand Margaret L. 
Published: February 2011

AbstractThe investigation of children with suspected inherited platelet disorders is challenging. The causes of mucocutaneous bleeding are many, and specialized testing for platelet disorders can be difficult to access or interpret. An algorithm developed for the investigation of suspected platelet disorders provides a sequential approach to evaluating both platelet function abnormalities and thrombocytopenia. Investigation begins with a clinical evaluation and laboratory testing that is generally available, including platelet counting, peripheral blood cell morphology, and aggregometry. Based on results of initial investigations, the algorithm recommends specialized testing for specific diagnoses, including flow cytometry, immunofluorescence microscopy, electron microscopy, and mutational analysis. Pediatr Blood Cancer 2011;56:975–983. © 2011 Wiley‐Liss, Inc.
Fludarabine, cyclophosphamide, doxorubicin (FCD), and rituximab: A remission induction therapy for aggressive pediatric post‐transplant lymphoproliferative disease (PTLD)
Authors: Giraldi Eugenia , Provenzi Massimo , Fiocchi Roberto , Colledan Michele , Cornelli Pieremilio , Torre Giuliano , Rambaldi Alessandro , Conter Valentino 
Published: February 2011

AbstractManagement of aggressive, usually late‐occurring, post‐transplant lymphoproliferative disorders (PTLDs), a life‐threatening complication after solid organ transplants, remains controversial. Four children affected by aggressive CD20+ PTLDs received a chemo‐immunotherapy regimen for remission induction based on fludarabine, cyclophosphamide, doxorubicin, and rituximab, associated with a rapid discontinuation of immunosuppression (IS). Subsequent consolidation chemotherapy consisted of Berlin‐Frankfurt‐Münster‐modified blocks. All patients achieved a complete remission, which persisted for 25, 68+, 80+, and 103+ months after diagnosis. Therapy was well tolerated. No patients developed allograft rejection during PTLD treatment. Our experience suggests that this chemo‐immunotherapeutic approach may be an effective treatment strategy while allowing for a concomitant discontinuation of IS. Pediatr Blood Cancer 2011; 57: 324–328. © 2011 Wiley‐Liss, Inc.