bluuebunny/crossref_metadata_2025_split huggingface dataset:
Negative modulation of eNOS by laminin involving post‐translational phosphorylation
Authors: Kumar V.B. Sameer , Viji R.I. , Kiran M.S. , Sudhakaran P.R. 
Published: December 2008

AbstractNitric oxide (NO) regulates the vascular tone, and influences survival and apoptosis of endothelial cells (ECs). NO is produced by nitric oxide synthase (NOS) and eNOS is the constitutive enzyme in the endothelium. Though the extracellular matrix (ECM) has been reported to regulate various EC functions, the role of ECM in the regulation of eNOS is not clear. The present study was designed to analyze if laminin‐1 (Ln‐1), the major glycoprotein of the basement membrane, can regulate eNOS. The activity of eNOS was significantly low in ECs maintained on Ln‐1 as compared to those on Col I and polylysine. Reversal of the effect of Ln‐1 on treatment with inhibitor of p38 MAPK and changes in Thr and Ser phosphorylation in purified eNOS suggested that eNOS activity in cells maintained on Ln‐1 is negatively regulated by post‐translational phosphorylation at Ser and Thr residues by recruiting p38 MAPK pathway. Increase in eNOS activity and induction of apoptosis upon inhibition of p38 MAPK and reversal of this on inhibition of NOS by L‐NAME suggested that increased NO induced apoptosis in ECs maintained on Ln‐1 when p38 MAPK was inhibited. These results suggest that Ln contributes to survival of ECs by negatively modulating eNOS in a p38 MAPK dependent pathway. J. Cell. Physiol. 219: 123–131, 2009. © 2008 Wiley‐Liss, Inc.
Modulation of muscle rNav1.4 Na+ channel isoform by arachidonic acid and its non‐metabolized analog
Authors: Gu Hua , Fang Yan‐Jia , He Yan‐Lin , Sun Ji , Zhu Jian , Mei Yan‐Ai 
Published: December 2008

AbstractArachidonic acid (AA) and its metabolic products are important second messengers which exert many biological actions, including modulation of various ion channels. However, the blockage of muscle Na+ channel isoforms by AA has not been examined in detail. Here, we investigated the modulating effects of AA on muscle rNaV1.4 isoforms expressed in human embryonic kidney 293 cells. The results revealed that AA has both activation and inhibitory effects on rNaV1.4 currents depending on the depolarizing potential: AA increased the rNaV1.4 current evoked by a depolarization of −30 or −40 mV, but significantly decreased the rNaV1.4 current evoked by a depolarization of membrane potential over −10 mV. At concentrations of 1–500 µM, the inhibitory effect on the rNaV1.4 current induced by AA was dose‐dependent and reversible. In addition to modulating the amplitude of the rNaV1.4 current, AA significantly modulated the steady‐state activation and inactivation properties of rNaV1.4 channels. Furthermore, treatment with AA resulted in a fairly slow recovery of the rNaV1.4 channel from inactivation; however, the inhibitory effect of AA was not changed by repetitive pulses or by changing frequency. The effect of AA on rNaV1.4 currents was completely mimicked by ETYA, the non‐metabolized analog of AA. Our data demonstrated that AA, but not the metabolic products of AA, can voltage‐dependent modulate rNaV1.4 currents. J. Cell. Physiol. 219: 173–182, 2009. © 2008 Wiley‐Liss, Inc.
Nuclear matrix binding site in the Rad51 recombinase
Authors: Mladenov Emil V. , Kalev Peter S. , Anachkova Boyka B. 
Published: December 2008

AbstractIt has been shown that the key homologous recombination protein Rad51accumulates in DNA damage‐induced nuclear foci that are attached to the nuclear matrix. In the present communication we attempted to find whether Rad51 contains a functional domain responsible for nuclear matrix binding. By alignments of the sequences encoding nuclear matrix targeting signals of human nuclear matrix binding proteins with the whole length human Rad51sequence a putative nuclear matrix targeting signal was identified. To prove that it is responsible for the nuclear matrix association of Rad51 18 base pairs encoding a cluster of hydrophobic amino acids in the human Rad51 Flag‐tagged gene were deleted. The formation of damage‐induced Rad51 foci and their association with the nuclear matrix were monitored in HeLa cells transfected with the wild‐type and the mutated Rad51gene after treatment with mitomycin C. The results showed that while the wild‐type protein formed Rad51 foci attached to the nuclear matrix, the mutated Rad51 failed to form DNA damage‐induced nuclear foci. The loss of foci formation activity of the mutated protein was not due to impaired ability to bind double‐stranded DNA in an ATP‐dependant way in vitro and to bind chromatin in vivo. These data suggest that the assembly of Rad51 into nuclear foci is assisted by association with the nuclear matrix, which may support the spatial organization of the process of repair by homologous recombination. J. Cell. Physiol. 219: 202–208, 2009. © 2008 Wiley‐Liss, Inc.
The Ape‐1/Ref‐1 redox antagonist E3330 inhibits the growth of tumor endothelium and endothelial progenitor cells: Therapeutic implications in tumor angiogenesis
Authors: Zou Gang‐Ming , Karikari Collins , Kabe Yasuaki , Handa Hiroshi , Anders Robert A. , Maitra Anirban 
Published: December 2008

AbstractThe apurinic/apyrimidinic endonuclease 1/redox factor‐1 (Ape‐1/Ref‐1) is a multi‐functional protein, involved in DNA repair and the activation of redox‐sensitive transcription factors. The Ape‐1/Ref‐1 redox domain acts as a cytoprotective element in normal endothelial cells, mitigating the deleterious effects of apoptotic stimuli through induction of survival signals. We explored the role of the Ape‐1/Ref‐1 redox domain in the maintenance of tumor‐associated endothelium, and of endothelial progenitor cells (EPCs), which contribute to tumor angiogenesis. We demonstrate that E3330, a small molecule inhibitor of the Ape‐1/Ref‐1 redox domain, blocks the in vitro growth of pancreatic cancer‐associated endothelial cells (PCECs) and EPCs, which is recapitulated by stable expression of a dominant‐negative redox domain mutant. Further, E3330 blocks the differentiation of bone marrow‐derived mesenchymal stem cells (BMSCs) into CD31+ endothelial progeny. Exposure of PCECs to E3330 results in a reduction of H‐ras expression and intracellular nitric oxide (NO) levels, as well as decreased DNA‐binding activity of the hypoxia‐inducible transcription factor, HIF‐1α. E3330 also reduces secreted and intracellular vascular endothelial growth factor expression by pancreatic cancer cells, while concomitantly downregulating the cognate receptor Flk‐1/KDR on PCECs. Inhibition of the Ape‐1/Ref‐1 redox domain with E3330 or comparable angiogenesis inhibitors might be a potent therapeutic strategy in solid tumors. J. Cell. Physiol. 219: 209–218, 2009. © 2008 Wiley‐Liss, Inc.
Multicompartmental analysis of late contrast enhancement in areas of myocardial infarction supplied by chronically occluded coronary arteries
Authors: Mandry Damien , Lapicque Françoise , Odille Freddy , Djaballah Wassila , Codreanu Andrei , Escanyé Jean‐Marie , Felblinger Jacques , Karcher Gilles , Claudon Michel , Marie Pierre‐Yves 
Published: December 2008

AbstractPurposeTo analyze the relationship between late contrast enhancement (LCE) and the interstitial distribution volume (VIn) of gadolinium (Gd) tracers in the myocardial infarction (MI) areas supplied by chronically occluded arteries from patients. In animal experimental models, LCE has already been shown to correspond to an enhanced VIn of Gd tracers and thus, to a decrease in the amount of intact cells.Materials and MethodsA multicompartmental analysis was applied to serial MRI images encompassing both infarct and remote areas and recorded with a conventional two‐dimensional (2D) segmented inversion‐recovery gradient‐echo (IR‐GRE) sequence during a 15‐minute period following Gd‐diethylenetriamine pentaacetic acid (Gd‐DTPA) injection in 12 patients with Q‐wave MI supplied by chronically occluded coronary arteries.ResultsVIn from infarct tissue was: 1) higher than VIn from remote areas (in % of myocardial volume: 74 ± 16% vs. 20 ± 7%, P < 0.001); and 2) correlated with the quantification of LCE between infarct and noninfarct areas at the 15th minute (R2 = 0.63, P = 0.002). However, the difference in VIn between infarct and remote myocardium was a much better correlate of this quantified LCE (R2 = 0.85, P < 0.001).ConclusionDetection of LCE in the MI territories supplied by chronically occluded arteries relates to the difference in the VIn of tracers between the infarct and the noninfarct areas. J. Magn. Reson. Imaging 2009;29:78–85. © 2008 Wiley‐Liss, Inc.
Susceptibility compensated fMRI study using a tailored RF echo planar imaging sequence
Authors: Chung Jun‐Young , Yoon Hyo Woon , Kim Young‐Bo , Park Hyun Wook , Cho Zang‐Hee 
Published: December 2008

AbstractPurposeTo implement a method using a tailored radiofrequency (TRF) pulse with a quadratic phase profile to recover susceptibility‐induced signal losses in gradient‐recalled echo‐planar images (EPI).Materials and MethodsA functional magnetic resonance imaging (fMRI) experiment for compensation of susceptibility artifacts, known as the TRF pulse EPI sequence (TRF‐EPI), was used. TRF pulse compensates the susceptibility effect with a reduced signal‐to‐noise ratio (SNR) to one‐half when the maximum phase distribution is 2π. We demonstrate theoretically that the maximum phase distribution can also be reduced to π rather than 2π, improving the SNR accordingly. An analysis was conducted comparing this newly proposed strategy using a standard RF excitation with a linear phase distribution and a quadratic TRF excitation with a π phase distribution.ResultsThorough experimental comparisons were also made between the TRF quadratic excitation with a π phase profile and conventional EPI with a standard excitation in human subjects during ventral brain activation.ConclusionWith reduced maximum phase distribution in the TRF pulse, signals in the susceptibility‐affected areas, such as the orbitofrontal and inferior temporal cortex, were increased, suggesting that the technique could be a useful adjunct to fMRI. J. Magn. Reson. Imaging 2009;29:221–228. © 2008 Wiley‐Liss, Inc.
3D coronary motion tracking in swine models with MR tracking catheters
Authors: Schmidt Ehud J. , Yoneyama Ryuichi , Dumoulin Charles L. , Darrow Robert D. , Klein Eric , Kiruluta Andrew J.M. , Hayase Motoya 
Published: December 2008

AbstractPurposeTo develop MR‐tracked catheters to delineate the three‐dimensional motion of coronary arteries at high spatial and temporal resolution.Materials and MethodsCatheters with three tracking microcoils were placed into nine swine. During breath‐holds, electrocardiographic (ECG)‐synchronized 3D motion was measured at varying vessel depths. 3D motion was measured in American Heart Association left anterior descending (LAD) segments 6–7, left circumflex (LCX) segments 11–15, and right coronary artery (RCA) segments 2–3, at 60–115 beats/min heart rates. Similar‐length cardiac cycles were averaged. Intercoil cross‐correlation identified early systolic phase (ES) and determined segment motion delay.ResultsTranslational and rotational motion, as a function of cardiac phase, is shown, with directionality and amplitude varying along the vessel length. Rotation (peak‐to‐peak solid‐angle RCA ≈0.10, LAD ≈0.06, LCX ≈0.18 radian) occurs primarily during fast translational motion and increases distally. LCX displacement increases with heart rate by 18%. Phantom simulations of motion effects on high‐resolution images, using RCA results, show artifacts due to translation and rotation.ConclusionMagnetic resonance imaging (MRI) tracking catheters quantify motion at 20 fps and 1 mm3 resolution at multiple vessel depths, exceeding that available with other techniques. Imaging artifacts due to rotation are demonstrated. Motion‐tracking catheters may provide physiological information during interventions and improve imaging spatial resolution. J. Magn. Reson. Imaging 2009;29:86–98. © 2008 Wiley‐Liss, Inc.
Three‐dimensional dynamic time‐resolved contrast‐enhanced MRA using parallel imaging and a variable rate k‐space sampling strategy in intracranial arteriovenous malformations
Authors: Petkova Mina , Gauvrit Jean‐Yves , Trystram Denis , Nataf François , Godon‐Hardy Sylvie , Munier Thierry , Oppenheim Catherine , Meder Jean‐François 
Published: December 2008

AbstractPurposeTo evaluate the effectiveness of three‐dimensional (3D) dynamic time‐resolved contrast‐enhanced MRA (TR‐CE‐MRA) using a combination of a parallel imaging technique (ASSET: array spatial sensitivity encoding technique) and a time‐resolved method (TRICKS: time‐resolved imaging of contrast kinetics) and to compare it with 3D dynamic TR‐CE‐MRA using ASSET alone in the assessment of intracranial arteriovenous malformations (AVMs).Materials and MethodsTwenty consecutive patients with angiographically confirmed AVMs were investigated using both 3D dynamic TR‐CE‐MRA techniques. Examinations were compared with respect to image quality, spatial resolution, number and type of feeders and drainers, nidus size, presence of early venous filling and temporal resolution. Digital subtraction angiography was used as standard of reference.ResultsThe higher temporal and spatial resolution of 3D dynamic TR‐CE‐MRA TRICKS ASSET allowed a better assessment of intracranial vascular malformations, namely better depiction of feeders, drainers and better detection of early venous drainage. There was no significant difference between them in terms of nidus size.Conclusion3D dynamic TR‐CE‐MRA combining parallel imaging and a time‐resolved method with subsecond and submillimeter resolution could become the first‐line investigation technique in both diagnosis and follow‐up of intracranial AVMs. J. Magn. Reson. Imaging 2009;29:7–12. © 2008 Wiley‐Liss, Inc.
Restricted canonical correlation analysis in functional MRI—validation and a novel thresholding technique
Authors: Ragnehed Mattias , Engström Maria , Knutsson Hans , Söderfeldt Birgita , Lundberg Peter 
Published: December 2008

AbstractPurposeTo validate the performance of an analysis method for fMRI data based on restricted canonical correlation analysis (rCCA) and adaptive filtering, and to increase the usability of the method by introducing a new technique for significance estimation of rCCA maps.Materials and MethodsActivation data from a language task and also a resting state fMRI data were collected from eight volunteers. Data was analyzed using both the rCCA method and the General Linear Model (GLM). A modified Receiver Operating Characteristic (ROC) method was used to evaluate the performance of the different analysis methods. The area under a fraction of the ROC curve was used as a measure of performance. On resting state data the fraction of voxels above certain significance thresholds were used to evaluate the significance estimation method.ResultsThe rCCA method scored significantly higher on the area under the ROC curve than the GLM. The fraction of activated voxels determined by thresholding according to the introduced significance estimation technique showed good agreement with the thresholds selected.ConclusionThe rCCA method is an effective analysis tool for fMRI data and its usability is increased with the introduced significance estimation method. J. Magn. Reson. Imaging 2009;29:146–154. © 2008 Wiley‐Liss, Inc.
Retrospective 3D registration of trabecular bone MR images for longitudinal studies
Authors: Magland Jeremy F. , Jones Catherine E. , Leonard Mary B. , Wehrli Felix W. 
Published: December 2008

AbstractPurposeTo evaluate an automatic 3D registration algorithm for serial high‐resolution images of trabecular bone (TB) in studies designed to evaluate the response of the trabecular architecture to intervention or disease progression.Materials and MethodsAn efficient algorithm for registering high‐resolution 3D images of TB is presented. The procedure identifies the six parameters of rigid displacement between two scans performed at different timepoints. By assuming a relatively small through‐plane rotation, considerable time is saved by combining the results of a collection of regional 2D registrations throughout the TB region of interest (ROI). The algorithm was applied to 26 pairs of MR images acquired 6 months apart. Reproducibility of local TB structural parameters (plate, rod, and junction density) computed in manually selected regions were compared between baseline and registered follow‐up images.ResultsAll 26 registrations were completed successfully in less than 30 seconds per image pair. The resampled follow‐up images agreed with baseline to around one pixel throughout the volume at 137 × 137 × 410 μm3 image resolution. Structural parameters in each region correlated well from baseline to follow‐up with intraclass correlation coefficients ranging between 85%–97% for TB plate density. Interregional variations in the parameters were large as compared with intraregion reproducibility.ConclusionThe proposed algorithm was successful in automatically registering baseline and follow‐up TB images in a translational study, and may be useful in regional analyses in longitudinal MR studies of TB architecture. J. Magn. Reson. Imaging 2009;29:118–126. © 2008 Wiley‐Liss, Inc.
Optimum fuzzy filters for phase‐contrast magnetic resonance imaging segmentation
Authors: Sundareswaran Kartik S. , Frakes David H. , Fogel Mark A. , Soerensen Dennis D. , Oshinski John N. , Yoganathan Ajit P. 
Published: December 2008

AbstractPurposeTo develop and validate a multidimensional segmentation and filtering methodology for accurate blood flow velocity field reconstruction from phase‐contrast magnetic resonance imaging (PC MRI).Materials and MethodsThe proposed technique consists of two steps: (1) the boundary of the vessel is automatically segmented using the active contour approach; and (2) the noise embedded within the segmented vector field is selectively removed using a novel fuzzy adaptive vector median filtering (FAVMF) technique. This two‐step segmentation process was tested and validated on 111 synthetically generated PC MRI slices and on 10 patients with congenital heart disease.ResultsThe active contour technique was effective for segmenting blood vessels having a sensitivity and specificity of 93.1% and 92.1% using manual segmentation as a reference standard. FAVMF was the superior technique in filtering out noise vectors, when compared with other commonly used filters in PC MRI (P < 0.05). The peak wall shear rate calculated from the PC MRI data (248 ± 39 sec−1), was significantly decreased to (146 ± 26 sec−1) after the filtering process.ConclusionThe proposed two‐step segmentation and filtering methodology is more accurate compared to a single‐step segmentation process for post‐processing of PC MRI data. J. Magn. Reson. Imaging 2009;29:155–165. © 2008 Wiley‐Liss, Inc.
Cerebral blood flow estimation in vivo using local tissue reference functions
Authors: Kosior Jayme Cameron , Smith Michael R. , Kosior Robert Karl , Frayne Richard 
Published: December 2008

AbstractPurposeTo evaluate the use of bolus signals obtained from tissue as reference functions (or local reference functions [LRFs]) rather than arterial input functions (AIFs) when deriving cross‐calibrated cerebral blood flow (CBFCC) estimates via deconvolution.Materials and MethodsAIF and white matter (WM) LRF CBFCC maps (cross‐calibrated so that normal WM was 23.7 mL/minute/100 g) derived using singular value decomposition (SVD) were examined in 28 ischemic stroke patients. Median CBFCC estimates from normal gray matter (GM) and ischemic tissue were obtained.ResultsAIF and LRF median CBFCC estimates resembled one another for all 28 patients (average paired CBFCC difference 0.4 ± 1.7 mL/minute/100 g and –0.4 ± 1.4 mL/minute/100 g in GM and ischemic tissue, respectively). Wilcoxon signed‐rank comparisons of patient median CBFCC measurements revealed no statistically significant differences between using AIFs and LRFs (P > 0.05).ConclusionIf CBF is quantified using a patient‐specific cross‐calibration factor, then LRF CBF estimates are at least as accurate as those from AIFs. Therefore, until AIF quantification is achievable in vivo, perfusion protocols tailored for LRFs would simplify the methodology and provide more reliable perfusion information. J. Magn. Reson. Imaging 2009;29:183–188. © 2008 Wiley‐Liss, Inc.
Combination of Mn2+‐enhanced and diffusion tensor MR imaging gives complementary information about injury and regeneration in the adult rat optic nerve
Authors: Thuen Marte , Olsen Øystein , Berry Martin , Pedersen Tina Bugge , Kristoffersen Anders , Haraldseth Olav , Sandvig Axel , Brekken Christian 
Published: December 2008

AbstractPurposeTo evaluate manganese (Mn2+)‐enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) as tools for detection of axonal injury and regeneration after intravitreal peripheral nerve graft (PNG) implantation in the rat optic nerve (ON).Materials and MethodsIn adult Fischer rats, retinal ganglion cell (RGC) survival was evaluated in Flurogold (FG) back‐filled retinal whole mounts after ON crush (ONC), intravitreal PNG, and intravitreal MnCl2 injection (150 nmol) at 0 and 20 days post lesion (dpl). MEMRI and echo‐planar DTI (DTI‐EPI) was obtained of noninjured ON one day after intravitreal MnCl2 injection, and at 1 and 21 dpl after ONC, intravitreal PNG, and intravitreal MnCl2 injections given at 0 and 20 dpl. GAP‐43 immunohistochemistry was performed after the last MRI.ResultsONC reduced RGC density in retina by 94% at 21 dpl compared to noninjured ON without MnCl2 injections. Both intravitreal PNG and intravitreal MnCl2 injections improved RGC survival in retina, which was reduced by 90% (ONC+MnCl2), 82% (ONC+PNG), and 74% (ONC+PNG+MnCl2) compared to noninjured ON. DTI‐derived parameters (fractional anisotropy [FA], mean diffusivity, axial diffusivity λ∥, and radial diffusivity λ⟂) were unaffected by the presence of Mn2+ in the ON. At 1 dpl, CNRMEMRI and λ∥ were reduced at the injury site, while at 21 dpl they were increased at the injury site compared to values measured at 1 dpl. GAP‐43 immunoreactive axons were present in the ON distal to the ONC injury site.ConclusionMEMRI and DTI enabled detection of functional and structural degradation after rat ON injury, and there was correlation between the MRI‐derived and immunohistochemical measures of axon regeneration. J. Magn. Reson. Imaging 2009;29:39–51. © 2008 Wiley‐Liss, Inc.
Novel technique used to detect swallowing in volume‐selective turbo spin‐echo (TSE) for carotid artery wall imaging
Authors: Chan Cheuk F. , Gatehouse Peter D. , Hughes Ray , Roughton Michael , Pennell Dudley J. , Firmin David N. 
Published: December 2008

AbstractPurposeTo improve three‐dimensional (3D) volume‐selective turbo spin‐echo (TSE) carotid wall imaging by the addition of a novel body surface swallowing detection device.Material and MethodsA 3D volume‐selective TSE sequence was used to image the carotid artery. A novel carbon‐fiber motion device, positioned over the laryngeal prominence, was used to detect swallowing movement. An electrical output generated by coil movement was used to detect motion, and an algorithm was programmed to reject data acquired during swallowing and for a short period afterwards. Images were acquired with and without the algorithm and scored on a scale of 0–5 by four independent blinded observers according to the clarity of the vessel wall, e.g., 0 = poor image quality and 5 = excellent quality images with little or no artifact.ResultsThe scans with the rejection algorithm on were scored higher than the scans without the algorithm. The comparison of scores with the algorithm on vs. the algorithm off were as follows: mean ± standard deviation (SD) = 3.76 ± 0.25, 95% confidence interval (CI) = 3.27–4.25 vs. 2.64 ± 0.25, 95% CI = 2.15–3.13; with good interobserver correlation (Kendall's W score 0.77).ConclusionImage quality can be improved by the algorithm during acquisition. This can be achieved by a novel, anatomically positioned superficial device. This may help in prolonged 3D scans where a single movement can corrupt the entire acquisition. J. Magn. Reson. Imaging 2009;29:211–216. © 2008 Wiley‐Liss, Inc.