bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival of a cohort of elderly patients with advanced dementia: nasogastric tube feeding as a risk factor for mortality
Authors: Alvarez‐Fernández Baldomero , García‐Ordoñez Miguel Angel , Martínez‐Manzanares Carlos , Gómez‐Huelgas Ricardo
Published: March 2005

Objectives

To evaluate and identify factors determining survival in elderly patients with advanced dementia.

Methods

A prospective, follow‐up, observational analysis in a cohort of 67 community‐based patients aged 65 years or older with dementia defined by DSM‐IV and stage 7A or above on the FAST scale. Data were recorded on socio‐demographic variables, FAST, Katz index, language, swallowing ability, diet, nutritional status (from anthropometric and laboratory data), associated diseases and medical complications during the previous 12 months. Survival was analyzed by the Kaplan‐Meier method. Prognostic factors for survival were identified by the Cox proportional hazards regression model.

Results

The median follow‐up was 832 days. The mean age was 82.2±6.7 years and 92.5% were women. A comorbid condition was present in 71.6%, most frequently hypertension (22.4%). A clinical event had occurred in 52 (77.6%) patients during the previous year (pneumonia, urinary infection, stroke, pressure sore, dehydration, sepsis or others). A total of 25 (37.3%) patients died. The mean survival was 676 days (95% confidence interval, 600–752 days). Cox proportional hazards model showed that independent prognostic factors for mortality were having pneumonia within the previous year (RR:3.7; p=0.001), a permanent nasogastric tube (RR:3.5; p=0.003) and serum albumin values below 3.5 g/dL (RR:2.9; p=0.028).

Conclusions

In patients with advanced dementia, hypoalbuminemia and pneumonia are strongly and positively associated with mortality. Artificial nutrition via a nasogastric tube reduces survival in these patients. Copyright © 2005 John Wiley & Sons, Ltd.
ER Ca2+ depletion triggers apoptotic signals for endoplasmic reticulum (ER) overload response induced by overexpressed reticulon 3 (RTN3/HAP)
Authors: Kuang Ersheng , Wan Qingwen , Li Xiaojuan , Xu Hua , Liu Qingzhen , Qi Yipeng
Published: March 2005

Perturbance of endoplasmic reticulum (ER) function, either by the mutant proteins not folding correctly, or by an excessive accumulation of proteins in the organelle, will lead to the unfolded protein response (UPR) or ER overload response (EOR). The signal‐transducing pathways for UPR have been identified, whereas the pathway for EOR remains to be elucidated. Our previous study demonstrated that the overexpression of reticulon 3 (RTN3, also named HAP, homologue of ASY protein) caused apoptosis with the depletion of ER Ca2+ stores. In present research, we characterized RTN3 as a novel EOR‐induced protein, triggering the apoptotic signals through the release of ER Ca2+ and the elevation of cytosolic Ca2+. Our studies showed that overexpressed RTN3 induced EOR, eliciting ER‐specific apoptosis with activation of caspase‐12 and mitochondrial dysfunction through ER Ca2+ depletion and the sustained elevation of cytosolic Ca2+. Furthermore, we demonstrated that overexpressed RTN3 and stimuli that activate both EOR and UPR, not UPR only, were able to induce up‐regulation of inducible nitric oxide synthase (iNOS) in HeLa cells through ER Ca2+ release and reactive oxygen intermediates (ROIs), resulting in endogenous calcium‐dependent nitric oxide protecting cells against ER specific apoptosis, which suggested that the nitric oxide and iNOS represented a likely protective response to EOR, not the UPR. These results supported that the release of ER Ca2+ stores triggered the initial signal‐transducing pathways for EOR induced by overexpressed RTN3. © 2005 Wiley‐Liss, Inc.
Go G‐proteins mediate rapid heterologous desensitization of G‐protein coupled receptors in Xenopus oocytes
Authors: Van‐Ham Irit Itzhaki , Oron Yoram
Published: March 2005

We have shown previously that responses to lysophosphatidic acid (LPA) in Xenopus oocytes exhibit pronounced rapid homologous desensitization mediated by Go family of G‐proteins (Itzhaki‐Van Ham et al., 2004, J Cell Physiol, 200: 125–133). The present study was aimed at examining the involvement of Go G‐proteins in rapid heterologous desensitization of native and expressed G‐protein‐coupled receptors in Xenopus oocytes. Threshold stimulation of the native lysophosphatidic acid receptors (LPA‐Rs) induced about 50% rapid desensitization of responses evoked by stimulation of either native trypsin or expressed M1‐muscarinic cholinergic receptors (M1‐Rs). Similarly, threshold stimulation of expressed M1‐Rs or thyrotropin‐releasing hormone receptors induced 40% rapid desensitization of responses to LPA. Inactivation of all Gi/o G‐proteins with pertussis toxin (PTX) completely abolished rapid heterologous desensitization in all protocols. Depletion of either Gαo or Gαo1 by antisense oligodeoxynucleotides targeted at either member of the Gαo family decreased or completely abolished rapid heterologous desensitization. Expression of two dominant negative mutants of the human Gαo family, highly homologous to oocyte Gαo species, either decreased or virtually abolished rapid desensitization. Homologous and heterologous desensitizations of the LPA response were non‐additive and proceeded, apparently, via the same pathway. We conclude that Go G‐proteins mediate both homologous and heterologous rapid desensitization of responses mediated by G‐protein‐coupled receptors (GPCRs) coupled to the phosphoinositide phospholipase C‐inositol 1,4,5‐trisphosphate‐Ca2+ (PI‐PLC‐InsP3‐Ca2+) pathway in Xenopus oocytes. © 2005 Wiley‐Liss, Inc.
Chondrocyte cluster formation in agarose cultures as a functional assay to identify genes expressed in osteoarthritis
Authors: Quintavalla Joseph , Kumar Chandrika , Daouti Sherif , Slosberg Eric , Uziel‐Fusi Susan
Published: March 2005

Understanding altered gene expression in osteoarthritic cartilage can lead to new targets for drug intervention. We established a functional assay based on chondrocyte cluster formation, a phenotype associated with osteoarthritis (OA), to screen an OA cartilage gene library. Previous reports have demonstrated that normal chondrocytes grown in suspension culture maintain their chondrocytic phenotype, however, certain growth factors such as basic fibroblast growth factor (bFGF) will induce the cells to proliferate in tight clusters similar to those seen in osteoarthritic cartilage. In this study we validate that overexpression of bFGF by retrovirally transduced normal chondrocytes would similarly induce the proliferation of tight cell clusters. We then used this approach as a basis to set up a functional screen where an entire OA cartilage cDNA library was tranduced into normal chondrocytes to search for other genes that would also induce cluster formation. Seven potential genes were isolated from the OA gene library, including BPOZ, IL‐17 receptor C, NADH ubiquinone oxidoreductase, COMP, Soluble carrier 16 (MCT 3), C1r, and bFGF itself. None of the identified genes were upregulated by bFGF, however, all of them upregulated the expression of bFGF suggesting a common pathway. Although cluster formation is not considered to be destructive in OA cartilage, it is consistent with the disease and could yield answers to the altered phenotype. Further studies are needed to elucidate how these genes are linked to the disease state. © 2005 Wiley‐Liss, Inc.
A generalization of Turán's theorem
Authors: Sudakov Benny , Szabó Tibor , Van Vu H.
Published: March 2005

In this paper, we obtain an asymptotic generalization of Turán's theorem. We prove that if all the non‐trivial eigenvalues of a d‐regular graph G on n vertices are sufficiently small, then the largest Kt‐free subgraph of G contains approximately (t − 2)/(t − 1)‐fraction of its edges. Turán's theorem corresponds to the case d = n − 1. © 2005 Wiley Periodicals, Inc. J Graph Theory
Unusual nocturnal motor restlessness in a patient with spinocerebellar ataxia 3
Authors: Ghorayeb Imad , Provini Federica , Bioulac Bernard , Tison François
Published: March 2005

Video‐polysomnographic monitoring of a female patient with spinocerebellar ataxia 3 (SCA‐3) in whom rapid eye movement (REM) sleep behavior disorder was clinically suspected demonstrated recurrent episodes of unusual nocturnal motor restlessness occurring during non‐REM sleep and severely disturbing both the patient and her bed partner's sleep. Even if nocturnal manifestations are common features of SCA‐3 and increasingly recognized, such a case has never been reported before. We discuss this peculiar movement disorder as a particular manifestation of the wide spectrum of parasomnias occurring in such a rare neurodegenerative disease. © 2005 Movement Disorder Society
MRI correlates of alien leg‐like phenomenon in corticobasal degeneration
Authors: Hu William T. , Josephs Keith A. , Ahlskog J. Eric , Shin Cheolsu , Boeve Bradley F. , Witte Robert J.
Published: March 2005

We describe the clinical and neuroradiologic correlates in two patients with the clinical picture of CBD and alien leg phenomena. The MRI brain scan in both had unique focal abnormalities in the corresponding leg area of the homunculus that may be the substrate for the alien limb features. © 2005 Movement Disorder Society
Experimental measurement of extravascular parenchymal BOLD effects and tissue oxygen extraction fractions using multi‐echo VASO fMRI at 1.5 and 3.0 T
Authors: Lu Hanzhang , van Zijl Peter C. M.
Published: March 2005

Quantitative interpretation of BOLD fMRI signal changes has predominantly employed empirical models for the whole parenchyma and a calibration step is usually needed to determine the physiological parameters during activation. Although analytical expressions are available for the extravascular and intravascular components of the BOLD effects, it is difficult to experimentally separate tissue from blood signal contributions at the low magnetic fields in which most fMRI studies are performed. Even if this can be achieved, an additional problem that remains is the separation of two types of extravascular BOLD effects, namely those around microvasculature (in the parenchyma close to the site of activation) and those around draining macrovasculature (e.g., in tissue and CSF more remote from the site of activation). In the recently developed vascular space occupancy technique, blood signals are nulled and the activations are localized predominantly in gray matter, allowing experimental measurement of parenchymal extravascular R2* and its changes accompanying activation. When comparing such data with total parenchymal R2* changes in BOLD fMRI, the extravascular fractions were found to be 47 ± 7% (mean ± SEM, n = 4) and 67 ± 6% at 1.5 and 3.0 T, respectively, in line with expectations that intravascular BOLD contributions are reduced at higher field. The present approach provides a noninvasive means to determine parenchymal oxygen extraction fraction (OEF) in situ. During visual stimulation, OEF values measured at 1.5 and 3.0 T were in good agreement, giving 0.23 ± 0.01 and 0.21 ± 0.01, respectively. Magn Reson Med 53:808–816, 2005. © 2005 Wiley‐Liss, Inc.
Development of a 0.014‐inch magnetic resonance imaging guidewire
Authors: Qiu Bensheng , Karmarkar Parag , Brushett Chris , Gao Fabao , Kon Ryan , Kar Sourav , Atalar Ergin , Yang Xiaoming
Published: March 2005

The purpose of this study was to develop a standard 0.014‐inch intravascular magnetic resonance imaging guidewire (MRIG), a coaxial cable with an extension of the inner conductor, specifically designed for use in the small vessels. After a theoretical analysis, the 0.014‐inch MRIG was built by plating/cladding highly electrically conductive materials, silver or gold, over the inside and outside of the coaxial conductors. The conductors were made of superelastic, nonmagnetic, biocompatible materials, Nitinol or MP35N. Then, in comparison with a previously designed 0.032‐inch MRIG, the performance of the new 0.014‐inch MRIG in vitro and in vivo was successfully evaluated. This study represents the initial work to confirm the critical role of highly conductive and superelastic materials in building such small‐size MRIGs, which are expected to generate high‐resolution MR imaging of vessel walls/plaques and guide endovascular interventional procedures in the small vessels, such as the coronary arteries. Magn Reson Med 53:986–990, 2005. © 2005 Wiley‐Liss, Inc.
Effects of breathing and cardiac motion on spatial resolution in the microscopic imaging of rodents
Authors: Maï Wilfried , Badea Cristian T. , Wheeler Charles T. , Hedlund Laurence W. , Johnson G. Allan
Published: March 2005

One can acquire high‐resolution pulmonary and cardiac images in live rodents with MR microscopy by synchronizing the image acquisition to the breathing cycle across multiple breaths, and gating to the cardiac cycle. The precision with which one can synchronize image acquisition to the motion defines the ultimate resolution limit that can be attained in such studies. The present work was performed to evaluate how reliably the pulmonary and cardiac structures return to the same position from breath to breath and beat to beat across the prolonged period required for MR microscopy. Radiopaque beads were surgically glued to the abdominal surface of the diaphragm and on the cardiac ventricles of anesthetized, mechanically ventilated rats. We evaluated the range of motion for the beads (relative to a reference vertebral bead) using digital microradiography with two specific biological gating methods: 1) ventilation synchronous acquisition, and 2) both ventilation synchronous and cardiac‐gated acquisitions. The standard deviation (SD) of the displacement was ≤100 μm, which is comparable to the resolution limit for in vivo MRI imposed by signal‐to‐noise ratio (SNR) constraints. With careful control of motion, its impact on resolution can be limited. This work provides the first quantitative measure of the motion‐imposed resolution limits for in vivo imaging. Magn Reson Med 53:858–865, 2005. © 2005 Wiley‐Liss, Inc.
Multi‐slice echo‐planar spectroscopic MR imaging provides both global and local metabolite measures in multiple sclerosis
Authors: Mathiesen Henrik Kahr , Tscherning Thomas , Sorensen Per Soelberg , Larsson Henrik B.W. , Rostrup Egill , Paulson Olaf B. , Hanson Lars G.
Published: March 2005

MR spectroscopy (MRS) provides information about neuronal loss or dysfunction by measuring decreases in N‐acetyl aspartate (NAA), a metabolite widely believed to be a marker of neuronal viability. In multiple sclerosis (MS), whole‐brain NAA (WBNAA) has been suggested as a marker of disease progression and treatment efficacy in treatment trials, and the ability to measure NAA loss in specific brain regions early in the evolution of this disease may have prognostic value. Most spectroscopic studies to date have been limited to single voxels or nonlocalized measurements of WBNAA only, and longitudinal studies have often been hampered by standardization and reproducibility problems. Multi‐slice echo‐planar spectroscopic imaging (EPSI) is presented as a promising alternative to single‐voxel or nonlocalized spectroscopy for obtaining global metabolite estimates in MS. In the same session, measurements of metabolites in specific brain areas chosen after image acquisition (e.g., normal‐appearing white matter (NAWM), gray matter (GM), and lesions) can be obtained. The identification and exclusion of regions that are inadequate for spectroscopic evaluation in global assessments can significantly improve quality and reproducibility, as demonstrated by a low within‐subject variance in healthy controls. The reproducibility of the technique makes it a promising tool for future longitudinal spectroscopic studies of MS. Magn Reson Med 53:750–759, 2005. © 2005 Wiley‐Liss, Inc.
Dynamic dephasing changes in developing ischemic cerebral infarction in rats studied by Carr–Purcell T2 magnetic resonance imaging
Authors: Kavec Martin , Gröhn Olli H. J. , Gröhn Heidi I. , Garwood Michael , Kauppinen Risto A.
Published: March 2005

Carr–Purcell (CP) T2 MRI with adiabatic pulses, acquired with varying interecho interval (τCP), was used to study the time course of T2 and relative dynamic‐dephasing contrast in the rat brain. Exposure to 30 min of middle cerebral artery occlusion (MCAo) resulted in an irreversible increase in absolute CP‐T2 relaxation times. This was not associated with signal change in the relative dynamic‐dephasing images, as computed by subtracting short τCP CP‐T2 images from long τCP images and normalizing for long τCP images. A day after MCAo strong CP‐T2 hyperintensity and low apparent diffusion coefficient were evident in the striatum with a decline in relative dynamic‐dephasing contrast. Low dynamic dephasing contrast prevailed in striatum until day 5 post‐MCAo, returning to control levels with similar time course to normalizing T2 and diffusion. The present results show a novel behavior of dynamic‐dephasing contrast in poststroke brain tissue, providing data to assess the age of infarction in association to T2 images. Magn Reson Med 53:960–964, 2005. © 2005 Wiley‐Liss, Inc.
Quantification of choline compounds in human hepatic tumors by proton MR spectroscopy at 3 T
Authors: Li Chun‐Wei , Kuo Yueh Chun , Chen Chiao‐Yun , Kuo Yu‐Ting , Chiu Yen‐Yu , She Feng‐O , Liu Gin‐Chung
Published: March 2005

The quantification of choline‐containing compounds (Cho) in hepatic tumors by 1H MR spectroscopy (MRS) is of great interest because such compounds have been linked to malignancy. In this study, a practical external phantom replacement method for the absolute quantification of hepatic metabolites is demonstrated. We performed experiments at 3 T using a body coil, and used an external phantom containing choline chloride for calibration. We first tested the quantification strategy to confirm its suitability in vivo using a phantom of known concentration and normal brain tissue. The results obtained after coil loading and T1 and T2 effects were corrected for were consistent with the known concentration and previously published values. To demonstrate its feasibility, we applied the technique to liver studies conducted on five normal volunteers and four patients with hepatocellular carcinoma, and one patient (also in the latter group) who had undergone post‐transcatheter arterial chemoembolization (TACE). The Cho concentrations in the four patients were estimated to be 3.4, 6.3, 7.4, and 14.0 mM, respectively. These values are substantially higher than those obtained from the healthy volunteers (1.3 ± 0.9 mM (mean ± SD)). The results indicate that the proposed method is accurate and requires fewer tedious procedures for MRS; therefore, it may be a promising technique for evaluating response to treatment in liver cancer. Magn Reson Med 53:770–776, 2005. © 2005 Wiley‐Liss, Inc.
Multislice and multicoil phase‐sensitive inversion‐recovery imaging
Authors: Ma Jingfei
Published: March 2005

Phase‐sensitive inversion‐recovery (PSIR) imaging may provide enhanced T1 contrast. However, clinical implementation of PSIR imaging is hindered because image reconstruction with this method often lacks robustness and requires manual intervention, particularly for data acquired in multiple slices and with phased‐array coils. In this paper, a new algorithm suitable for automatic PSIR image reconstruction of multislice and multicoil data is presented. This algorithm phase corrects by region‐growing, employing both the magnitude and the phase information of image pixels. Specifically, phase gradients of the original complex image are first calculated and then used to determine the sequence of the region‐growing. The signal direction relating to the phase error for each pixel is then determined during the region‐growing using both the magnitude and the phase of the previously determined pixels that are located within a boxcar neighborhood of the pixel. Finally, the intrinsic intercoil and interslice correlation is exploited to ensure consistency in the global polarity of all of the PSIR images. The results are demonstrated with in vivo human brain images acquired at 3 Tesla with an eight‐channel phased‐array coil. Magn Reson Med 53:904–910, 2005. © 2005 Wiley‐Liss, Inc.
Calculation of left ventricle relative pressure distribution in MRI using acceleration data
Authors: Buyens Fanny , Jolivet Odile , De Cesare Alain , Bittoun Jacques , Herment Alain , Tasu Jean‐Pierre , Mousseaux Elie
Published: March 2005

Measurements of pressure variations within the cardiac chambers could provide important information for clinical assessments of cardiovascular function. In this work an MRI method for evaluating spatial distributions of intracardiac relative pressure is presented. We first calculated pressure gradients from MR maps of blood acceleration by applying the NS equation. We then used an original algorithm to compute pressure distribution in a region of interest (ROI) by minimizing the pressure gradient curl so that the result in a given pixel is independent of the integration path. The method was assessed in five healthy volunteers by means of MR 2D maps of the blood acceleration in the left ventricle (LV) during ejection and filling phases. The pressure variations calculated from acceleration mapping fit the known physiological variations better than those based on velocity maps acquired in the same volunteers. Furthermore, the optimization algorithm presented here produced the same results as iterative algorithms proposed by other authors, but in much less time and without requiring adjustable parameters or boundary conditions. Magn Reson Med 53:877–884, 2005. © 2005 Wiley‐Liss, Inc.
Adrenergic stimulation of Rb+ uptake in pig hearts in vivo assessed by 87Rb MRS
Authors: Kupriyanov V.V. , Xiang B. , Sun J. , Jilkina O.
Published: March 2005

It was previously shown that the adrenergic agonist dobutamine stimulates Rb+ uptake in isolated pig hearts. In the present work we examined whether dobutamine can increase Rb+ uptake rate in vivo. Open‐chest domestic pigs (N = 14) were used under general anesthesia. The surface coil was placed against the anterior left ventricular wall to obtain 87Rb spectra using a spectrometer interfaced with the 7T, 30‐cm horizontal bore magnet. RbCl was infused at the rate of 1.35 ± 0.14 mmol/kg/hr without or with dobutamine (0.6 mg/kg/hr) over a 60‐min period, and then the infusions were terminated. The rate constant (k × 103, from 13 ± 2.4 to 36 ± 12 min−1) and Rb+ influx rate (from 2.5% to 4.8%/min) were increased by dobutamine despite lower plasma [Rb+] (0.59 ± 0.16 vs. 0.84 ± 0.24 mM in control), while the tissue/plasma Rb ratios were identical (38 ± 9). Heart rate (HR) and systolic blood pressure (SBP) were increased from 106 ± 9 to 161 ± 15 bpm (+52%) and from 78 ± 7 to 93 ± 11 mmHg (+19%), respectively. The stimulation of Rb+ uptake by dobutamine is consistent with the activation of Na+/K+ ATPase previously observed in isolated hearts. However, the 50% increase in HR and the double coronary flow caused by the SBP increase and vasodilatation may also contribute to this effect. Magn Reson Med 53:817–822, 2005. © 2005 Wiley‐Liss, Inc.
23Na MRI combined with contrast‐enhanced 1H MRI provides in vivo characterization of infarct healing
Authors: Hillenbrand Hanns B. , Becker Lewis C. , Kharrazian Reza , Hu Kai , Rochitte Carlos E. , Kim Raymond J. , Chen Enn L. , Ertl Georg , Hruban Ralph H. , Lima João A.C.
Published: March 2005

Although 23Na MRI has been shown to delineate acute myocardial infarction (MI), the time course of in vivo 23Na MRI during infarct healing remains unknown. In this study 23Na MRI was combined with contrast‐enhanced (CE) 1H MRI to noninvasively characterize infarct healing in vivo. Serial in vivo 3D 23Na MRI and 1H MRI were performed for up to 9 weeks postinfarction in 10 dogs. Radioactive microspheres were used to measure myocardial perfusion, and Hematoxylin‐Eosin (H&E) and Masson's trichrome (MT) staining were used to assess interstitial cell infiltrate and collagen content. In vivo 23Na MRI accurately delineated infarct size up to day 5 postinfarction in comparison with 1H MRI (8.9% ± 8.1% vs. 8.6% ± 7.9% on day 1 postinfarction, P = NS; and 6.3% ± 6.2% vs. 6.2% ± 6.2% on days 4/5 postinfarction, P = NS). The in vivo 23Na MRI signal intensity, expressed as the signal intensity ratio of infarcted tissue vs. noninfarcted tissue (MI/R) peaked on day 1 of infarction (2.04 ± 0.23) but decreased significantly to 1.27 at 9 weeks postinfarction (P < 0.05) due to granulation tissue infiltrate and collagen deposition. To confirm the MI/R decrease during scar formation ex vivo, we performed 23Na MRI in 12 rats on day 3 post‐MI (N = 5) and after 6 weeks (N = 7). H&E and Picrosirius Red staining confirmed granulation tissue infiltrate on day 3 and scar formation after 6 weeks. MI/R decreased significantly from 1.91 ± 0.45 on day 3 post‐MI to 1.3 ± 0.09 after 6 weeks. Thus, in vivo 23Na MRI accurately delineates infarct size up to day 5 postinfarction. In vivo 23Na MRI signal intensity decreases during infarct healing as a result of the underlying infarct healing process. Magn Reson Med 53:843–850, 2005. © 2005 Wiley‐Liss, Inc.
1H MR spectroscopy using TE averaged PRESS: A more sensitive technique to detect neurodegeneration associated with Alzheimer's disease
Authors: Hancu Ileana , Zimmerman Earl A. , Sailasuta Napapon , Hurd Ralph E.
Published: March 2005

A sensitive proton magnetic resonance spectroscopy (1H MRS) acquisition scheme that is capable of discriminating between normal controls and a group of patients with early Alzheimer's disease (AD) is presented. The performance of this newly developed method, TE averaged PRESS (PRESS‐J), in detecting neurodegeneration associated with early AD is compared with that of short echo time (TE) PRESS. A stepwise discriminant function analysis is used to construct discriminant functions for both pulse sequences. These functions are each composed of a single predictor: the N‐acetyl aspartate (NAA)/creatine (Cr) ratio for PRESS‐J, and the NAA/myoInositol (mI) ratio for PRESS. We observed lower P‐values, higher areas under the receiver operating characteristic curves, and higher sensitivity at a given specificity for the PRESS‐J discriminating function in comparison with the PRESS discriminating function. The higher sensitivity of PRESS‐J is due to decreased variability when the singlets are fit in the spectra. This increased sensitivity enables new MR applications and, among other benefits, allows for smaller group sizes in drug trials, which can significantly reduce the cost of such trials. Magn Reson Med 53:777–782, 2005. © 2005 Wiley‐Liss, Inc.
Open half‐volume quadrature transverse electromagnetic coil for high‐field magnetic resonance imaging
Authors: Peshkovsky A. S. , Kennan R. P. , Fabry M. E. , Avdievich N. I.
Published: March 2005

A half‐volume quadrature head transverse electromagnetic (TEM) coil has been constructed for 4 T imaging applications. This coil produces a sufficiently large homogeneous B1 field region for the use as a volume coil. It provides superior transmission efficiency, resulting in significantly lower power deposition, as well as greater sensitivity and improved patient comfort and accessibility compared with conventional full‐volume coils. Additionally, this coil suppresses the RF penetration artifact that distorts the RF magnetic field profile and alters the intensity in high‐field images recorded with linear surface and volume coils. These advantages make it possible to apply this device as an efficient transmit/receive coil for high‐field imaging with a restricted field of view. Magn Reson Med 53:937–943, 2005. © 2005 Wiley‐Liss, Inc.
Fast, accurate, and automatic extraction of the modified talairach cortical landmarks from magnetic resonance images
Authors: Hu Qingmao , Qian Guoyu , Nowinski Wieslaw L.
Published: March 2005

The Talairach transformation is the most prevalent way to normalize brains and is hindered by, among others things, a lack of automatic determination of cortical landmarks. An algorithm to locate the modified Talairach cortical landmarks in three steps is proposed: determination of the three planes containing the landmarks; segmentation of the planes based on range‐constrained thresholding and morphologic operations; and local refinement of the segmentation to locate the landmarks. The algorithm has been validated against 62 T1‐weighted and SPGR MR diversified data sets. For each data set, it takes less than 2 s on a Pentium 4 to extract all six landmarks. The average landmark location errors are below 0.9 mm. The algorithm is robust due to incorporation of anatomic knowledge. A low computational cost results from processing of three 2D images and employing only simple operations like thresholding, basic morphologic operations, and distance transform. Magn Reson Med 53:970–976, 2005. © 2005 Wiley‐Liss, Inc.
Uncovering hidden in vivo resonances using editing based on localized TOCSY
Authors: Marjanska Malgorzata , Henry Pierre‐Gilles , Bolan Patrick J. , Vaughan Brooks , Seaquist Elizabeth R. , Gruetter Rolf , Uğurbil Kâmil , Garwood Michael
Published: March 2005

A novel single‐shot spectral editing technique for in vivo proton NMR is proposed to recover resonances of low‐concentration metabolites obscured by very strong resonances. With this new method, editing is performed by transferring transverse magnetization to J‐coupled spins from selected coupling partners using a homonuclear Hartmann–Hahn polarization transfer with adiabatic pulses. The current implementation uses 1D‐TOCSY with single‐voxel localization based on LASER to recover the H1 proton of β‐glucose at 4.63 ppm from under water and the lactate methyl resonances from beneath a strong lipid signal. The method can be extended to further spin systems where conventional editing methods are difficult to perform. Magn Reson Med 53:783–789, 2005. © 2005 Wiley‐Liss, Inc.
Rotating‐frame intermolecular double‐quantum spin‐lattice relaxation T1ρ, DQC‐weighted magnetic resonance imaging
Authors: Zheng Bingwen , Hwang Dennis W. , Chen Zhong , Hwang Lian‐Pin
Published: March 2005

In this study, spin‐locking techniques were added as a part of intermolecular multiple‐quantum experiments, thereby introducing the concept of rotating‐frame intermolecular double‐quantum spin‐lattice relaxation, T1ρ, DQC. A novel magnetic resonance imaging methodology based on intermolecular multiple‐quantum coherences is demonstrated on a 7.05‐T microimaging scanner. The results clearly reveal that the intermolecular double‐quantum coherence T1ρ, DQC‐weighted imaging technique provides an alternative contrast mechanism to conventional imaging. Magn Reson Med 53:930–936, 2005. © 2005 Wiley‐Liss, Inc.
Contrast‐to‐noise ratios of diffusion anisotropy indices
Authors: Kingsley Peter B. , Monahan W. Gordon
Published: March 2005

The degree of diffusion anisotropy in different brain regions is usually measured by a diffusion anisotropy index (DAI) such as relative anisotropy (RA) and fractional anisotropy (FA). FA has been reported to have a higher contrast‐to‐noise ratio (CNR) than RA. The present work compares the CNRs of seven DAIs in theoretical propagation‐of‐error calculations, in simulations, and in human brain measurements over small and large anisotropy differences. In simulations all seven CNRs were similar for small anisotropy differences. Small differences among the DAIs appeared at higher anisotropy levels and lower signal‐to‐noise ratios with certain tensor orientations. The DAIs fell into three groups based on algebraic relationships and small CNR differences. The group with RA and FA had the best CNR. Human brain regions with small anisotropy differences had similar CNR for all seven DAIs, and the scatter in the data was greater than any expected differences. With large anisotropy differences, a small advantage appeared for RA over FA in some simulations and for FA over RA in other simulations. The CNR between brain regions with very different anisotropies was different for each DAI. The apparent reported advantage of FA over RA is explained by biologic heterogeneity and by noise‐induced bias in the DAI values and their standard deviations. Magn Reson Med 53:911–918, 2005. © 2005 Wiley‐Liss, Inc.
Visualization of cortical spreading depression using manganese‐enhanced magnetic resonance imaging
Authors: Henning Erica C. , Meng Xiangjun , Fisher Marc , Sotak Christopher H.
Published: March 2005

Cortical spreading depression (CSD) was visualized using manganese‐enhanced MRI (MEMRI) following topical application of KCl to the exposed rat cortex. MEMRI signal increase in the ipsilateral cortex relative to the contralateral control region was 60 ± 30% following two KCl applications. MEMRI signal increase for a single (40%) versus double (80%) KCl application suggests an integration effect over successive CSD episodes. CSD‐induced MEMRI enhancement involved cortical layers containing dense regions of apical dendrites, supporting the contention that these neuronal structures are necessary for propagation of CSDs. Subcortical enhancement was present in hippocampal and thalamic regions, most likely a result of neuronal connections with cortical layers 4 and 5. These results are consistent with previous studies of CSD using diffusion‐weighted MRI and T2*‐weighted MRI and should be useful for investigating CSD itself and its role in other neurologic disorders. Magn Reson Med 53:851–857, 2005. © 2005 Wiley‐Liss, Inc.
Iopamidol: Exploring the potential use of a well‐established x‐ray contrast agent for MRI
Authors: Aime Silvio , Calabi Luisella , Biondi Luca , De Miranda Mario , Ghelli Stefano , Paleari Lino , Rebaudengo Cristina , Terreno Enzo
Published: March 2005

Iopamidol is one of the most common contrast media used for diagnostic CT‐based clinical protocols. Chemically, this molecule contains two pools of mobile protons (amide and alcoholic) that are in exchange with water. At 7.05 T, pH 7.4, and 312 K, the exchange rate of the alcoholic protons is too fast to affect the NMR properties of water protons, whereas the slowly exchanging amide protons induce a T2‐shortening effect on the “bulk” water signal that is detectable when the concentration is about 12 mM. Moreover, a more pronounced contrast is observed when the amide resonances are saturated by the application of an appropriate RF irradiation field, making iopamidol a potential chemical exchange saturation transfer (CEST) agent whose effect can be detected at a concentration as low as 7 mM (at 7.05 T). The exploitation of the MRI properties of iopamidol could facilitate novel and interesting diagnostic applications for combined MRI and CT studies. Magn Reson Med 53:830–834, 2005. © 2005 Wiley‐Liss, Inc.
Short breath‐hold, volumetric coronary MR angiography employing steady‐state free precession in conjunction with parallel imaging
Authors: Niendorf Thoralf , Saranathan Manojkumar , Lingamneni Anila , Pedrosa Ivan , Spencer Matthew , Cline Harvey , Foo Thomas K.F. , Rofsky Neil M.
Published: March 2005

An ECG‐gated, 3D steady‐state free precession (SSFP) technique in conjunction with sensitivity encoding (SENSE)‐based parallel imaging was implemented for short breath‐hold, volumetric coronary MR angiograpy (CMRA). Two parallel imaging acquisition strategies (employing 1 R‐R and 2 R‐R intervals, respectively) were developed to achieve 1) very short breath‐hold times (12 s for a heart rate of 60 bpm), and 2) small acquisition windows to minimize sensitivity to physiologic motion. Both strategies were examined in CMRA applications over a range of heart rates. A four‐point scale blinded reading (with 4 indicating the most desirable features) revealed substantial image quality improvements for the accelerated data as compared to the nonaccelerated approach. The 1 R‐R interval scheme yielded an image score of 3.39 ± 0.60, and was found to be particularly suitable for low heart rates (P = 0.0008). The 2 R‐R interval strategy yielded an image score of 3.35 ± 0.64, and was more appropriate for higher heart rates (P = 0.03). The results demonstrate that 3D SSFP combined with parallel imaging is a versatile method for short breath‐hold CMRA while maintaining high spatial resolution. This strategy permits imaging of the major coronary artery distributions in two to three breath‐holds using targeted slabs, and offers the potential for single breath‐hold, large‐volume CMRA. Magn Reson Med 53:885–894, 2005. © 2005 Wiley‐Liss, Inc.
3He lung imaging in an open access, very‐low‐field human magnetic resonance imaging system
Authors: Mair R. W. , Hrovat M. I. , Patz S. , Rosen M. S. , Ruset I. C. , Topulos G. P. , Tsai L. L. , Butler J. P. , Hersman F. W. , Walsworth R. L.
Published: March 2005

The human lung and its functions are extremely sensitive to gravity; however, the conventional high‐field magnets used for most laser‐polarized 3He MRI of the human lung restrict subjects to lying horizontally. Imaging of human lungs using inhaled laser‐polarized 3He gas is demonstrated in an open‐access very‐low‐magnetic‐field (<5 mT) MRI instrument. This prototype device employs a simple, low‐cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two‐dimensional plane. As a demonstration, two‐dimensional lung images were acquired with 4‐mm in‐plane resolution from a subject in two orientations: lying supine and sitting in a vertical position with one arm raised. Experience with this prototype device will guide optimization of a second‐generation very‐low‐field imager to enable studies of human pulmonary physiology as a function of subject orientation. Magn Reson Med 53:745–749, 2005. © 2005 Wiley‐Liss, Inc.
Analysis of a new BEM‐FEM coupling for two‐dimensional fluid‐solid interaction
Authors: Meddahi Salim , Sayas Francisco‐Javier
Published: March 2005

In this work we present a new numerical method, based on a coupling of finite and boundary elements, to solve a fluid‐solid interaction problem in the plane. The discrete method uses classical Lagrange finite elements adapted to curved boundaries for the field variable and spectral approximation of the unknowns on the artificial boundary. We provide error estimates for this Galerkin scheme and propose a full discretization based on elementary quadrature formulae, showing that the perturbation due to numerical integration preserves the optimal rate of convergence. We also suggest an iterative method to solve the complicated linear systems arising from this type of schemes. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
A mixed nonconforming finite element for linear elasticity
Authors: Cai Zhiqiang , Ye Xiu
Published: March 2005

This article considers a mixed finite element method for linear elasticity. It is based on a modified mixed formulation that enforces the continuity of the stress weakly by adding a jump term of the approximated stress on interior edges. The symmetric stress are approximated by nonconforming linear elements and the displacement by piecewise constants. We establish 𝒪(h) error bound in the (broken) L2 norm for the divergence of the stress and 𝒪(h) error bound in the L2 norm for both the displacement and the stress tensor. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005.
Role of afterload reduction in the prevention of late anthracycline cardiomyopathy
Authors: Silber Jeffrey H.
Published: March 2005

Afterload reduction is useful for treating and preventing adult congestive heart failure outside the realm of anthracycline toxicity. Afterload reducers are commonly used as treatment for acute heart failure associated with anthracyclines. However, the use of afterload reduction for the prevention of anthracycline associated late cardiomyopathy remains a controversial area, with strong opinions expressed concerning the potential risks and benefits of such an approach. This article will define “afterload” and the tools utilized to measure afterload. The study will then describe the theory for the use of afterload reduction in patients with anthracycline exposure who show signs of anthracycline cardiotoxicity, and will present data from the ACE‐Inhibitor After Anthracyclines (AAA) Trial to help answer the question, “Should an afterload reducer be used to aid in preventing late anthracycline cardiotoxicity?” Finally, recommendations for future research will be presented. Pediatr Blood Cancer 2005;44:607–613. © 2005 Wiley‐Liss, Inc.
Clinical and molecular characteristics of pediatric gastrointestinal stromal tumors (GISTs)
Authors: Price Victoria E. , Zielenska Maria , Chilton‐MacNeill Susan , Smith Charles. R. , Pappo Alberto S.
Published: March 2005

Background

To describe the clinical characteristics, molecular features, treatment, and outcome of six pediatric patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods

Retrospective clinical review of GISTs, seen at The Hospital for Sick Children (HSC) Toronto, over an 11‐year period. All specimens were stained for the CD 117 and CD 34 antigens. Three specimens were sequenced for mutations in exons 9, 11, and 13 of the c‐kit gene.

Results

Five patients were evaluated and treated at HSC and one was referred for histopathological consultation only. The median patient age at diagnosis was 13.6 years, (6.9–14.8 years); four were female. All patients presented with anemia secondary to gastrointestinal (GI) bleeding. The disease was localized in five patients and two had other malignancies consistent with the diagnoses of Carney's triad. Immunohistochemical staining for CD 117 and CD 34 showed heavy cytoplasmic localization in all of the tumor cells. A novel point mutation of KIT in codon 456 of exon 9 was found in one case. Complete surgical resection was achieved in the five patients managed at our center and none received adjuvant therapies. Disease recurred locally in one patient. Four patients are alive and one is lost to follow‐up.

Conclusions

In children and adolescents, GISTs should be considered in the differential diagnosis of anemia secondary to GI hemorrhage. The absence of an exon 11 mutation and the identification of a novel mutation in exon 9 suggest that pediatric GISTs may respond differently to currently available targeted therapies and therefore should be studied within the context of collaborative group trials. Pediatr Blood Cancer 2005; 45:20–24. © 2005 Wiley‐Liss, Inc.
Crystallization kinetics and melting behaviour of microbial poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)
Authors: Chen Cheng , Cheung Man Ken , Yu Peter HF
Published: March 2005

Isothermal and non‐isothermal crystallization kinetics of microbial poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) [P(3HB‐3HHx)] was investigated by differential scanning calorimetry (DSC) and 13C solid‐state nuclear magnetic resonance (NMR). Avrami analysis was performed to obtain the kinetic parameters of primary crystallization. The results showed that the Avrami equation was suitable for describing the isothermal and non‐isothermal crystallization processes of P(3HB‐3HHx). The equilibrium melting temperature of P(3HB‐3HHx) and its nucleation constant of crystal growth kinetics, which were obtained by using the Hoffman–Weeks equation and the Lauritzen–Hoffmann model, were, respectively, 121.8 °C and 2.87 × 105 K2 when using the empirical ‘universal’ values of U* = 1500 cal mol−1. During the heating process, the melting behaviour of P(3HB‐3HHx) for both isothermal and non‐isothermal crystallization showed multiple melting peaks, which was the result of melting recrystallization. The lower melting peak resulted from the melting of crystals formed during the corresponding crystallization process, while the higher melting peak resulted from the recrystallization that took place during the heating process. Copyright © 2005 Society of Chemical Industry
Synthesis and characterization of poly(o‐anisidine)/V2O5 and poly(o‐anthranilic acid)/V2O5 nanocomposites
Authors: Wang Gengchao , Wang Lin , Li Xingwei
Published: March 2005

Poly(o‐anisidine)/V2O5 and poly(o‐anthranilic acid)/V2O5 nanocomposites were prepared by in situ intercalative polymerization, and the structure and electrical properties of these nanocomposites were investigated using GPC, TGA, XRD, TEM, FTIR, UV‐vis as well as conductivity measurement. The results show that the steric effect and nature of the substituting groups in the aromatic ring has an influence on the structure and electrical properties of the nanocomposites. Poly(o‐anisidine) or poly(o‐anthranilic acid) exists as a monolayer of outstretched chains in the gallery of the V2O5 xerogel owing to the confined environment in the nanometer‐size gallery. And intercalation of poly(o‐anisidine) or poly(o‐anthranilic acid) can improve the conductivity of V2O5 xerogel. Copyright © 2005 Society of Chemical Industry
Enantiomer ratio of MK‐0767 in humans and nonclinical species
Authors: Shen Zhongzhou , Bakhtiar Ray , Komuro Masakatsu , Awano Katsuya , Taga Fukutaro , Colletti Adria , Hora Don , Feeney William , Iliff Susan , Franklin Ronald B. , Vincent Stella
Published: March 2005

MK‐0767, (±)‐5‐[(2,4‐dioxothiazolidin‐5‐yl)methyl]‐2‐methoxy‐N‐[[(4‐trifluoromethyl)phenyl]methyl]benzamide, is a thiazolidinedione‐containing dual peroxisome proliferator‐activated receptor (PPAR) α/γ agonist that has been studied as a potential treatment for patients with type 2 diabetes. MK‐0767 contains a chiral center at the C‐5 position of the thiazolidinedione ring and was being developed as the racemate, due to the rapid interconversion of its enantiomers in biological samples. In the present work the in vitro and in vivo concentration ratios of the (+)‐(R) to (−)‐(S) enantiomers of MK‐0767 were determined in plasma from humans (in vitro only) and nonclinical species used in the toxicological evaluation of rac‐MK‐0767, namely CD‐1 mice, Sprague‐Dawley rats, beagle dogs, New Zealand white rabbits, and rhesus monkeys. The R/S ratio was determined by chiral liquid chromatography/tandem mass spectrometry. Species differences were observed in the in vitro and in vivo enantiomeric ratios, as well as differences between in vitro and in vivo in some species. The in vitro R/S ratio was similar in dogs and humans (∼1.5–1.7). In rats and monkeys, the ratio was approximately unity, both in vitro and in vivo. In mice, the ratio was higher in vitro (∼1) than in vivo (∼0.6), while in rabbits it was higher in vivo (∼1) than in vitro (∼0.5). These results suggested that differential binding of the MK‐0767 enantiomers to plasma and tissue proteins and other macromolecules may be affecting the R/S ratio both in vitro and in vivo, since in protein‐free systems MK‐0767 exists as the racemate. Copyright © 2005 John Wiley & Sons, Ltd.
Fyn binding protein, Fyb, interacts with mammalian actin binding protein, mAbp1
Authors: Yuan Ming , Mogemark Lena , Fällman Maria
Published: March 2005

The immune cell specific protein Fyn‐T binding protein (Fyb) has been identified as a target of the Yersinia antiphagocytic effector Yersinia outer protein H (YopH), but its role in macrophages is unknown. By using Fyb domains as bait to screen a mouse lymphoma cDNA library, we identified a novel interaction partner, mammalian actin binding protein 1 (mAbp1). We show that mAbp1 binds the Fyb N‐terminal via its C‐terminally located src homology 3 domain. The interaction between Fyb and mAbp1 is detected in macrophage lysates and the proteins co‐localize with F‐actin in the leading edge. Hence, mAbp1 is likely to constitute a downstream effector of Fyb involved in F‐actin dynamics.