bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Catalysis and Nanoscience: An Inseparable Pair
Authors: Zecchina Adriano , Groppo Elena , Bordiga Silvia
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Proteases in Plant Root Symbiosis
Authors: Takeda Naoya , Kistner Catherine , Kosuta Sonja , Winzer Thilo , Pitzschke Andrea , Groth Martin , Sato Shusei , Kaneko Takakazu , Tabata Satoshi , Parniske Martin
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Looking Beyond the RNA Structural Neighborhood for Potentially Primordial Genetic Systems
Authors: Sutherland John D.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
(+)‐Lentiginosine, a Potent and Selective Inhibitor of Amyloglucosidase: Synthetic Efforts and Disputes on Its Absolute Configuration
Authors: Cardona Francesca , Goti Andrea , Brandi Alberto
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
e‐Malaria: the schools Malaria project
Authors: Geldhill Robert , Kent Sarah , Milsted Andrew , Chapman Richard , Essex Jonathan W. , Frey Jeremy G.
Published: May 2007

e‐Malaria (http://emalaria.soton.ac.uk/) aims to bring together 16–18 year old school students with university researchers to explain aspects of computational drug design using the example of the hunt for a new anti‐Malaria drug. Malaria kills a child every 30 seconds, and 40% of the world's population lives in countries where the disease is endemic. Resistance to existing drugs is increasing and there is a growing need for new compounds. This challenge is being offered to school students who will use a distributed drug search and selection system via a Web interface to design potential drugs. The project makes use of industrial code for the docking study (‘GOLD’) and as such presents valuable lessons in how to achieve the integration of industrial programs into a ‘free’ outreach environment. The results of the trials are displayed in an accessible manner, giving students an opportunity for discussion and debate both with peers and with university contacts. The initial project has been extended to provide a similar challenge for undergraduate chemists as part of a chemical informatics course at a level relevant to more advances chemical skills. Copyright © 2007 John Wiley & Sons, Ltd.
AMUSE: autonomic management of ubiquitous e‐Health systems
Authors: Lupu E. , Dulay N. , Sloman M. , Sventek J. , Heeps S. , Strowes S. , Twidle K. , Keoh S.‐L. , Schaeffer‐Filho A.
Published: May 2007

Future e‐Health systems will consist of low‐power on‐body wireless sensors attached to mobile users that interact with an ubiquitous computing environment to monitor the health and well being of patients in hospitals or at home. Patients or health practitioners have very little technical computing expertise so these systems need to be self‐configuring and self‐managing with little or no user input. More importantly, they should adapt autonomously to changes resulting from user activity, device failure, and the addition or loss of services. We propose the Self‐Managed Cell (SMC) as an architectural pattern for all such types of ubiquitous computing applications and use an e‐Health application in which on‐body sensors are used to monitor a patient living in their home as an exemplar. We describe the services comprising the SMC and discuss cross‐SMC interactions as well as the composition of SMCs into larger structures. Copyright © 2007 John Wiley & Sons, Ltd.
Steering via the image in local, distributed and collaborative settings
Authors: Wood J. D. , Wright H.
Published: May 2007

Computational steering is a valuable mechanism for scientific investigation in which the parameters of a running program can be altered and the results visualized immediately. In a previous paper we put forward an architecture for computational steering that recognizes visualization as both the logical output and the input route. In this paper we investigate the practicalities of applying this architecture in local, distributed and collaborative steering. The work adopts a state‐transition modelling approach, keeping parameters and results together in the display in order to present information consistently. The outcome is a manageably small set of states that could apply to many different simulations. We also present the results of a preliminary user study on the demonstrator we have constructed. Copyright © 2007 John Wiley & Sons, Ltd.
Performance analysis of a semantics‐enabled service registry
Authors: Fang W. , Miles S. , Moreau L.
Published: May 2007

Service discovery is a critical task in service‐oriented architectures. In this paper, we study GRIMOIRES, the semantics‐enabled service registry of the OMII software distribution, from a performance perspective. We study the scalability of GRIMOIRES against the amount of information that has been published into it. The methodology we use and the data we present are helpful for researchers to understand the performance characteristics of the registry and, more generally, of semantics‐enabled service discovery. Based on this experimentation, we claim that GRIMOIRES is an efficient semantics‐aware service discovery engine. Copyright © 2007 John Wiley & Sons, Ltd.
Expression and function of the IL‐2 receptor in activated human plasmacytoid dendritic cells
Authors: Naranjo‐Gómez Mar , Oliva Harold , Climent Nuria , Fernández Marco A. , Ruiz‐Riol Marta , Bofill Margarita , Gatell José M. , Gallart Teresa , Pujol‐Borrell Ricardo , Borràs Francesc E.
Published: May 2007

Human and mouse plasmacytoid dendritic cells (PDC) express IL‐2 mRNA specifically upon TLR stimulation, but not under CD40L stimulation. Even though the expression of the IL‐2R by PDC has been described, the functional implications of this expression remain unknown. Here, we investigated the expression and function of the IL‐2R in activated human PDC. The IL‐2Rα chain, CD25, is expressed in both CpG‐ and CD40L‐activated PDC. CD25 expression is a relatively rapid event, as the receptor was detected 6 h after the initial activation signal. Exogenous IL‐2 added to CD40L‐activated PDC increased the expression of CD25, enhanced the secretion of pro‐inflammatory cytokines and promotes PDC survival. CpG‐activated PDC cultured in the presence of IL‐2R‐blocking monoclonal antibodies showed a reduced expression of pro‐inflammatory cytokines, especially TNF‐α. This reduction was dose and time dependent, suggesting a regulatory role of IL‐2 in TNF secretion that might occur at the post‐transcriptional level. These results indicate that the expression of the IL‐2R is relevant to human PDC activation, and that IL‐2 may be an important auto‐ and/or paracrine factor modulating the activation and survival of PDC. Finally, CD25 expression may be considered as a useful early activation marker for human PDC.
A Linear Ru‐Tl‐Ru Complex Obtained from Halide Abstraction: An Example of Metal‐Dative Bonding
Authors: Bytheway Ian , Griffith Christopher S. , Koutsantonis George A. , Skelton Brian W. , White Allan H.
Published: May 2007

The simple abstraction of chloride ion from [RuCl(CO)2(η‐C5H5)] using [TlBF4] proved problematic, unexpectedly giving a new complex containing linear Ru–Tl–Ru. The complex, [{Ru(CO)2(η‐C5H5)}2(μ‐Tl)(F–BF2–F)]∞, was polymeric, as determined by a single‐crystal X‐ray diffraction experiment, in which the thallium centres are bridged by the anions. In an effort to compare the nature of the Tl–Ru bonds, an additional complex was prepared by the reaction of Tl3+ions with [Ru(CO)2(η‐C5H5)]–. The resulting neutral complex, [{Ru(CO)2(η‐C5H5)}3(μ‐Tl)], was also structurally characterised. Quantum chemical calculations of [{Ru(CO)2(η‐C5H5)}2(μ‐Tl)][BF4] suggest that the Tl–Ru bond has ionic character with integrated atomic charges showing that the metal–metal bonding is best represented as Ru0–TlI–Ru0. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Interrogation of MS/MS search data with an pI Filter algorithm to increase protein identification success
Authors: Uwaje Nkemdilim C. , Mueller Nikola S. , Maccarrone Giuseppina , Turck Christoph W.
Published: May 2007

In high‐throughput proteomics, the bottom‐up approach has become a widely used method for the identification of proteins that is based on tryptic peptide MS/MS analysis. Separation methodologies that use IEF of tryptic peptides have recently been introduced and provide an extra dimension of peptide separation. In addition to its great fractionation capability, tryptic peptide prefractionation by IEF can also increase the protein identification success. The pI information of the peptide gained can be successfully used in a post‐database search filtering step. We introduce a filtering algorithm that is based on the comparison of the experimental and theoretical pI's to validate peptide identifications by MS/MS data search engines.
Identification of host genes involved in hepatitis C virus replication by small interfering RNA technology
Authors: Ng Teresa I. , Mo Hongmei , Pilot-Matias Tami , He Yupeng , Koev Gennadiy , Krishnan Preethi , Mondal Rubina , Pithawalla Ron , He Wenping , Dekhtyar Tanya , Packer Jeremy , Schurdak Mark , Molla Akhteruzzaman
Published: May 2007

Hepatitis C virus (HCV) replication is highly dependent on host cell factors. Identification of these host factors not only facilitates understanding of the biology of HCV infection but also enables the discovery of novel targets for anti-HCV therapy. To identify host genes important for HCV RNA replication, we screened a library of small interfering RNA (siRNA) that targets approximately 4,000 human genes in Huh7-derived EN5-3 cells harboring an HCV subgenomic replicon with the nonstructural region NS3-NS5B from the 1b-N strain. Nine cellular genes that potentially regulate HCV replication were identified in this screen. Silencing of these genes resulted in inhibition of HCV replication by more than 60% and exhibited minimal toxicity. Knockdown of host gene expression by these siRNAs was confirmed at the RNA level and, in some instances, at the protein level. The level of siRNA silencing of these host genes correlated well with inhibition of HCV. These genes included those that encoded a G-protein coupled receptor (

TBXA2R

), a membrane protein (

LTβ

), an adapter protein (

TRAF2

), 2 transcription factors (

RelA

and

NFκB2

), 2 protein kinases (

MKK7

and

SNARK

), and 2 closely related transporter proteins (

SLC12A4

and

SLC12A5

). Of interest, some of these genes are members of the tumor necrosis factor/lymphotoxin signaling pathway.

Conclusion:

Findings of this study may provide important information for understanding HCV replication. In addition, these cellular genes may constitute a novel set of targets for HCV antiviral therapy. (Hepatology 2007.)
Incidence of non-Hodgkin's lymphoma among individuals with chronic hepatitis B virus infection
Authors: Ulcickas Yood Marianne , Quesenberry Charles P. , Guo Dianlin , Caldwell Cary , Wells Karen , Shan Jun , Sanders Lynn , Skovron Mary Lou , Iloeje Uchenna , Manos Michele M.
Published: May 2007

Although hepatitis C virus (HCV) infection has been shown to be associated with development of non-Hodgkin's lymphoma (NHL), few studies have investigated the association between chronic HBV infection and NHL. The purpose of this study was to compare the incidence of NHL between patients with and without chronic hepatitis B virus (HBV) infection. Using automated laboratory result and clinical data from two United States health systems, we identified individuals with chronic HBV infection from January 1, 1995 through December 31, 2001. Using each health system's population-based tumor registry, we identified all cases of NHL diagnosed through December 31, 2002. We excluded any individual with a history of NHL or human immunodeficiency virus (HIV). We fit Cox proportional hazards models to calculate hazard ratios comparing the incidence of NHL between chronic HBV-infected patients (N = 3,888) and patients without HBV (N = 205,203) drawn from the source populations. We identified 8 NHL cases in the chronic HBV infection cohort and 111 cases in the comparison cohort. Patients with chronic HBV infection were 2.8 times more likely to develop NHL than matched comparison patients (adjusted hazard ratio = 2.80, 95% confidence interval = 1.16-6.75), after controlling for age, race, sex, income, Charlson comorbidity index, study site, and HCV infection.

Conclusion:

chronic HBV-infected patients were nearly 3 times more likely to develop NHL than comparison patients. (HEPATOLOGY 2007.)
Redox-dependent and ligand-independent trans -activation of insulin receptor by globular adiponectin
Authors: Fiaschi Tania , Buricchi Francesca , Cozzi Giacomo , Matthias Stephanie , Parri Matteo , Raugei Giovanni , Ramponi Giampietro , Chiarugi Paola
Published: May 2007

Adiponectin/ACRP30 is an adipose tissue–derived hormone with antiatherogenic, antidiabetic, and insulin-sensitizing properties. Although the metabolic effects of adiponectin on glucose and lipid metabolism are well known, the signaling pathways triggered by adiponectin receptors remain to be elucidated. We report evidence that in hepatic cells, adiponectin stimulation produces a transient burst of reactive oxygen species (ROS) through activation of the small GTPase Rac1 and 5-lypoxigenase. Furthermore, adiponectin-induced oxidants cause the oxidation/inhibition of protein-tyrosine phosphatase (PTP) 1B, one of the major phosphotyrosine phosphatases involved in the control of insulin receptor phosphorylation. Adiponectin causes increased association of PTP1B to insulin receptor and the oxidation/inhibition of the phosphatase, ultimately provoking the ligand-independent

trans

-phosphorylation of insulin receptor. We also report evidence that redox signaling plays a key role in both mitogen-activated protein kinase activation and hepatic glucose consumption induced by adiponectin.

Conclusion:

These results point to ROS as critical regulators of the cross-talk between adiponectin and insulin pathways and provide a redox-based molecular mechanism for the insulin-sensitizing function of adiponectin. (HEPATOLOGY 2007.)
On the structure of the inverse kinematics map of a fragment of protein backbone
Authors: Milgram R. J. , Liu Guanfeng , Latombe J. C.
Published: May 2007

Loop closure in proteins requires computing the values of the inverse kinematics (IK) map for a backbone fragment with 2n ≥ 6 torsional degrees of freedom (dofs). It occurs in a variety of contexts, e.g., structure determination from electron‐density maps, loop insertion in homology‐based structure prediction, backbone tweaking for protein energy minimization, and the study of protein mobility in folded states. The first part of this paper analyzes the global structure of the IK map for a fragment of protein backbone with 6 torsional dofs for a slightly idealized kinematic model, called the canonical model. This model, which assumes that every two consecutive torsional bonds CαC and NCα are exactly parallel, makes it possible to separately compute the inverse orientation map and the inverse position map. The singularities of both maps and their images, the critical sets, respectively, decompose SO(3) × ℝ3 into open regions where the number of IK solutions is constant. This decomposition leads to a constructive proof of the existence of a region in ℝ3 × SO(3) where the IK of the 6‐dof fragment attains its theoretical maximum of 16 solutions. The second part of this paper extends this analysis to study fragments with more than 6 torsional dofs. It describes an efficient recursive algorithm to sample IK solutions for such fragments, by identifying the feasible range of each successive torsional dof. A numerical homotopy algorithm is then used to deform the IK solutions for a canonical fragment into solutions for a noncanonical fragment. Computational results for fragments ranging from 8 to 30 dofs are presented. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Rapid dark‐blood carotid vessel‐wall imaging with random bipolar gradients in a radial SSFP acquisition
Authors: Lin Hung‐Yu , Flask Chris A. , Dale Brian M. , Duerk Jeffrey L.
Published: May 2007

Purpose

To investigate and evaluate a new rapid dark‐blood vessel‐wall imaging method using random bipolar gradients with a radial steady‐state free precession (SSFP) acquisition in carotid applications.

Materials and Methods

The carotid artery bifurcations of four asymptomatic volunteers (28–37 years old, mean age = 31 years) were included in this study. Dark‐blood contrast was achieved through the use of random bipolar gradients applied prior to the signal acquisition of each radial projection in a balanced SSFP acquisition. The resulting phase variation for moving spins established significant destructive interference in the low‐frequency region of k‐space. This phase variation resulted in a net nulling of the signal from flowing spins, while the bipolar gradients had a minimal effect on the static spins. The net effect was that the regular SSFP signal amplitude (SA) in stationary tissues was preserved while dark‐blood contrast was achieved for moving spins. In this implementation, application of the random bipolar gradient pulses along all three spatial directions nulled the signal from both in‐plane and through‐plane flow in phantom and in vivo studies.

Results

In vivo imaging trials confirmed that dark‐blood contrast can be achieved with the radial random bipolar SSFP method, thereby substantially reversing the vessel‐to‐lumen contrast‐to‐noise ratio (CNR) of a conventional rectilinear SSFP “bright‐blood” acquisition from bright blood to dark blood with only a modest increase in TR (∼4 msec) to accommodate the additional bipolar gradients.

Conclusion

Overall, this sequence offers a simple and effective dark‐blood contrast mechanism for high‐SNR SSFP acquisitions in vessel wall imaging within a short acquisition time. J. Magn. Reson. Imaging 2007;25:1299–1304. © 2007 Wiley‐Liss, Inc.
Magnetic resonance imaging to assess acute changes in atrial and ventricular parameters after transcatheter closure of atrial septal defects
Authors: Burgstahler Christof , Wöhrle Jochen , Kochs Matthias , Nusser Thorsten , Löffler Christine , Kunze Markus , Höher Martin , Gawaz Meinrad P. , Hombach Vinzenz , Merkle Nico
Published: May 2007

Purpose

To evaluate acute changes in atrial and ventricular parameters by the use of cardiac magnetic resonance imaging (MRI) in patients with percutaneous transcatheter atrial septal defects (ASD) closure.

Materials and Methods

The study included 14 patients (six males and eight females, 45 ± 18 years) with congenital ASD. Cardiac MRI (1.5T Philips Intera CV) was performed before and within 24 hours after transcatheter ASD closure. Right atrial (RA) and left atrial (LA) dimensions, as well as right (RV) and left (LV) ventricular end‐diastolic (ED) volumes were determined. Atrial size was assessed by planimetry of the maximum RA and LA areas in a standard four‐chamber view, and ventricular volumes were calculated according to a modified Simpson's rule in short‐axis views.

Results

The mean RA decreased significantly from 27.6 ± 6.4 cm2 before closure to 24.4 ± 5.6 cm2 after the procedure (P = 0.0018), whereas the LA area did not change (24.1 ± 4.7 cm2 vs. 23.8 ± 5.2 cm2, P = 0.76). The RV volumes, volume index, and ejection fraction (EF) decreased significantly from 229 ± 64 mL to 181 ± 43 mL (P < 0.001, average reduction = 19% ± 15%), from 126.0 ± 37.2 mL/m2 to 96.6 ± 28.6 mL/m2 (P < 0.0001) and from 64 ± 5% to 58% ± 7% (P = 0.01), respectively. The LV volumes and volume index remained unchanged (114 ± 25 mL vs. 118 ± 22 mL, P = 0.18, 63.5 ± 13.5 mL/m2 vs. 63.0 ± 17.4 mL/m2, P = 0.83). Left–right shunting decreased from 40% ± 15% to 9% ± 15% (P < 0.001).

Conclusion

Cardiac MRI can reveal detailed information on acute changes in shunt fraction and ventricular dimensions after ASD closure. ASD closure by percutaneous transcatheter device implantation results within 24 hours in a significant reduction of shunt fraction, RA and RV sizes, and RV function, whereas LA and LV dimensions remain unchanged. J. Magn. Reson. Imaging 2007;25:1136–1140. © 2007 Wiley‐Liss, Inc.
Normalized left ventricular volumes and function in thalassemia major patients with normal myocardial iron
Authors: Westwood Mark A. , Anderson Lisa J. , Maceira Alicia M. , Shah Farrukh T. , Prescott Emma , Porter John B. , Wonke Beatrix , Walker J. Malcolm , Pennell Dudley J.
Published: May 2007

Purpose

To determine the reference range in thalassemia major (TM) for left ventricular (LV) function.

Materials and Methods

We used cardiovascular magnetic resonance (CMR) to measure heart volumes and function in 81 TM patients with normal myocardial T2* measurements (T2* > 20 msec) and by inference without excess myocardial iron. Forty age‐ and gender‐matched healthy controls were also studied.

Results

Resting LV volumes and function normalized to body surface area differed significantly between TM patients and controls. The lower limit and the mean for ejection fraction (EF) were higher in TM patients (males 59 vs. 55%, mean 71% vs. 65%; females 63 vs. 59%, mean 71% vs. 67%; both P < 0.001). The upper limit and mean for end‐diastolic volume index were higher in TM patients (males 152 vs. 105 mL/m2, mean 97 vs. 84 mL/m2; females 121 vs. 99 mL/m2, mean 87 vs. 79 mL/m2; both P < 0.05). In TM patients the cardiac index (P < 0.001) was increased.

Conclusion

At rest, TM patients with a normal myocardial T2* have different “normal” values for LV volume and function parameters compared to controls, and this has the potential to lead to a misdiagnosis of cardiomyopathy. We present new reference “normal” ranges in TM to alleviate this problem. J. Magn. Reson. Imaging 2007;25:1147–1151. © 2007 Wiley‐Liss, Inc.
High‐speed 3T MR spectroscopic imaging of prostate with flyback echo‐planar encoding
Authors: Chen Albert P. , Cunningham Charles H. , Ozturk‐Isik Esin , Xu Duan , Hurd Ralph E. , Kelley Douglas A.C. , Pauly John M. , Kurhanewicz John , Nelson Sarah J. , Vigneron Daniel B.
Published: May 2007

Prostate MR spectroscopic imaging (MRSI) at 3T may provide two‐fold higher spatial resolution over 1.5T, but this can result in longer acquisition times to cover the entire gland using conventional phase‐encoding. In this study, flyback echo‐planar readout trajectories were incorporated into a Malcolm Levitt's composite‐pulse decoupling sequence (MLEV)–point‐resolved spectroscopy sequence (PRESS) to accelerate the acquisition of large array (16 × 16 × 8), high spatial (0.154 cm3) resolution MRSI data by eight‐fold to just 8.5 minutes. Artifact free, high‐quality MRSI data was obtained in nine prostate cancer patients. Easy data reconstruction and the robustness of the flyback echo‐planar encoding make this technique particularly suitable for the clinical setting. The short acquisition time provided by this method reduces the 3T prostate MRI/MRSI exam time, allows longer repetition times, and/or allows the acquisition of additional MR acquisitions within the same exam. J. Magn. Reson. Imaging 2007;25:1288–1292. © 2007 Wiley‐Liss, Inc.
Cardiac amyloidosis: MR imaging findings and T1 quantification, comparison with control subjects
Authors: Krombach Gabriele A. , Hahn Christa , Tomars Maren , Buecker Arno , Grawe Armin , Günther Rolf W. , Kühl Harald P.
Published: May 2007

In cardiac amyloidosis an interstitial deposition of amyloid fibrils causes concentric thickening of the atrial and ventricular walls. We describe the results of tissue characterization of the myocardium by T1 quantification and MRI findings in a patient with cardiac amyloidosis. The T1 time of the myocardium was elevated compared to that in individuals without amyloidosis. The T1 time of the myocardium was 1387 ± 63 msec (mean value obtained from four measurements ± standard deviation [SD]) in the patient with cardiac amyloidosis, while the reference value obtained from the myocardium of 10 individuals without known myocardial disease was 1083 ± 33 msec (mean value ± SD). In combination with other MR findings suggestive of amyloidosis, such as homogeneous thickening of the ventricular and atrial walls, thickening of the valve leaflets, restrictive filling pattern, and reduction of systolic function, T1 quantification may increase diagnostic confidence. J. Magn. Reson. Imaging 2007;25:1283–1287. © 2007 Wiley‐Liss, Inc.
High cerebral blood volume in human gliomas predicts deletion of chromosome 1p: Preliminary results of molecular studies in gliomas with elevated perfusion
Authors: Law Meng , Brodsky Jennie E. , Babb James , Rosenblum Marc , Miller Douglas C. , Zagzag David , Gruber Michael L. , Johnson Glyn
Published: May 2007

Purpose

To determine if increased perfusion using dynamic susceptibility contrast perfusion MRI (DSC MRI) in gliomas may be predictive of 1p19q deletions. Loss of heterozygosity of chromosomes 1p and 19q confers responsiveness to chemotherapy improving survival in gliomas.

Materials and Methods

We retrospectively reviewed 16 patients who had DSC MRI and molecular studies of their excised gliomas for 1p19q deletions. Allelic status was assessed by loss of heterozygosity using polymerase chain reaction (PCR). DNA was extracted from paraffin curls of brain tumor sections and nail clippings. Relative cerebral blood volume (rCBV) measurements were then statistically compared with the presence of 1p and 19q deletions.

Results

Patients with 1p19q deletions (N = 7) demonstrated rCBV values of 10.54 ± 2.93. Patients without 1p deletions (N = 9) had rCBV values of 4.84 ± 2.4 (P = 0.012). Logistic regression demonstrated that rCBV was able to predict the presence of a 1p deletion to significance levels of 0.038 and 0.044, adjusted and not adjusted for age and sex, respectively. The kappa coefficient for the agreement between predicted deletion status using rCBV and the truedeletion status was 0.746 (P = 0.0028). Deletions of 19q alone, or together with 1p deletions, were not associated with high rCBV.

Conclusion

Histopathologic, molecular, and imaging evidence supports increased neovascularity in gliomas with 1p deletions in this preliminary study. We propose a diagnostic algorithm to obtain molecular studies in gliomas demonstrating high rCBV. J. Magn. Reson. Imaging 2007;25:1113–1119. © 2007 Wiley‐Liss, Inc.
Comparison of biphasic and reordered fat suppression for dynamic breast MRI
Authors: Desmond Kimberly L. , Ramsay Elizabeth A. , Plewes Donald B.
Published: May 2007

Purpose

To optimize a reordered k‐space acquisition that applies intermittent fat saturation (FS) pulses to allow for a time‐efficient reduction of fat signal in breast MR images, and compare it with an elliptic‐centric biphasic FS method in terms of the degree of fat suppression and speed.

Materials and Methods

The behavior of the fat and water signals under the influence of the reordered sequence was characterized. This allowed us to optimize the flip angle and visualize the expected artifacts by deriving the point spread function (PSF) of the fat signal. We compared the two sequences by acquiring images with a varying number of FS pulses, with a corresponding difference in scan time. The quality of the images was assessed by comparison with images obtained with full fat suppression as measured by a root‐mean‐square (RMS) error metric.

Results

The reordered sequence allowed for an approximately twofold reduction in error compared to the biphasic sequence for the same scan time. With the reordered sequence and optimized scan parameters, we were able to reduce the time spent on fat suppression by as much as 99% with no discernible reduction in image quality.

Conclusion

This method will allow robust fat suppression with virtually no extension in imaging time for dynamic contrast‐enhanced (DCE)‐MRI. J. Magn. Reson. Imaging 2007;25:1293–1298. © 2007 Wiley‐Liss, Inc.
High temporal resolution breathheld 3D FIESTA CINE imaging: Validation of ventricular function in patients with chronic myocardial infarction
Authors: Rettmann Dan W. , Saranathan Manojkumar , Wu Katherine C. , Azevedo Clerio F. , Bluemke David A. , Foo Thomas K.F.
Published: May 2007

Purpose

To develop a gated single‐breathhold, high temporal resolution three‐dimensional (3D) CINE imaging technique and to evaluate its accuracy in volumetric and functional quantification in patients with chronic myocardial infarction.

Materials and Methods

A 3D CINE steady‐state free precession (SSFP) pulse sequence was developed incorporating variable temporal sampling of the low and high spatial frequency k‐space data to reduce breathhold time and parallel imaging to increase temporal resolution. Reconstruction with retrospective interpolation enabled complete R‐R interval coverage. Feasibility was assessed in eight patients with chronic myocardial infarction and ventricular functional values were compared to those of a 2D CINE acquisition.

Results

There was no significant difference between the 3D CINE and 2D CINE for end‐diastolic volume (168 ± 73 vs. 177 ± 59 mL, respectively; P < 0.27), end‐systolic volume (81 ± 62 vs. 79 ± 53 mL; P < 0.81), and ejection fraction (EF) measurements (55 ± 14% vs. 58 ± 14%; P < 0.14). The mean difference in EF was less than 2.5%. A wall motion assessment indicated a good agreement, with a weighted kappa value of 0.62.

Conclusion

High temporal resolution 3D CINE SSFP imaging of the whole heart can be obtained in a single breathhold and yield ventricular function measurements similar to 2D CINE methods. J. Magn. Reson. Imaging 2007;25:1141–1146. © 2007 Wiley‐Liss, Inc.
Misregistration artifacts in image‐derived arterial input function in non‐echo‐planar imaging‐based dynamic contrast‐enhanced MRI
Authors: Kuribayashi Hideto , Worthington Philip L. , Bradley Daniel P. , Checkley David R. , Tessier Jean J. , Waterton John C.
Published: May 2007

Purpose

To characterize misregistration artifact in arterial input function (AIF) pixels in dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) using a two‐dimensional non‐echo‐planar imaging (EPI)‐based gradient‐recalled echo (GRE) sequence.

Materials and Methods

Dynamic gadopentetate‐enhanced MRI was acquired in the rat using a semikeyhole acquisition scheme. The AIF was obtained from abdominal aorta pixels. Different sliding‐window reconstruction techniques were applied to determine which lines in a series of the semikeyhole acquisition were associated with the misregistration artifacts.

Results

The misregistration along the phase‐encoding direction arose when k‐space lines were acquired during the rise‐time of the aortic gadolinium concentration. The maximum blood concentration of gadolinium estimated from the phase shift calculation agreed with that estimated from dosage.

Conclusion

AIF misregistration results from a phase shift due to increasing gadolinium concentration in the aorta, and may need to be considered in small animal DCE‐MRI studies with a high rate of rise in the AIF in high‐field MR applications. J. Magn. Reson. Imaging 2007;25:1248–1255. © 2007 Wiley‐Liss, Inc.
Correction of temporal misregistration artifacts in jet flow by conventional phase‐contrast MRI
Authors: Doyle Mark , Kortright Eduardo , Anayiotos Andreas S. , Rayarao Geetha , Rathi Vikas K. , Caruppannan Kethes , Li Longchuan , Biederman Robert W.W.
Published: May 2007

Purpose

To show that accuracy of jet flow representation by magnetic resonance (MR) phase‐contrast (PC) velocity‐encoded (VE) cine imaging is dominated by error terms resulting from the temporal distribution of data, and to present a generally applicable data interpolation‐based approach to correct for this phenomenon.

Materials and Methods

Phase‐contrast data were acquired in a stenotic orifice flow phantom using a physiologic pulsatile flow waveform. A temporally registered scan, acquired without data segmentation or interleaving was obtained (17 minutes) and taken as the reference (REF). Conventional PC data sets were acquired using segmentation and data interleaving. An enhanced temporal registration (ETR) algorithm was applied to the acquired data to temporally interpolate component sets and output data at matching time points, thereby reducing temporal dispersion.

Results

Compared to the REF data, conventionally processed PC data consistently overestimated peak velocities in laminar jet flow regions (127% ± 28%) and exhibited relatively weak correlations (r = 0.67 ± 0.23). The ETR‐processed data better represented peak velocities (101% ± 13%, P < 0.001) and correlated more closely with the REF data (r = 0.94 ± 0.05, P < 0.001).

Conclusion

The temporal distribution of PC data impacts the accuracy of velocity representation in pulsatile jet flow. A temporal registration postprocessing algorithm can minimize loss of accuracy. J. Magn. Reson. Imaging 2007;25:1256–1262. © 2007 Wiley‐Liss, Inc.
Fluid‐induced wall shear stress in anthropomorphic brain aneurysm models: MR phase‐contrast study at 3 T
Authors: Ahn Sinyeob , Shin Dongsuk , Tateshima Satoshi , Tanishita Kazuo , Vinuela Fernando , Sinha Shantanu
Published: May 2007

Purpose

To study spatial and temporal distribution of wall shear stress (WSS) of intracranial aneurysm models using magnetic resonance phase contrast (MR‐PC) imaging, and to compare results to those obtained in our previous study using laser Doppler velocimetry (LDV).

Materials and Methods

High‐resolution MR‐PC imaging was performed on aneurysm models created from 3D in vivo data of a basilar artery (BA) tip and a middle cerebral artery (MCA) aneurysm. WSS was measured by calculating the rate of shearing strain using image postprocessing techniques. WSS was characterized using several parameters, including average WSS and oscillatory shear index (OSI).

Results

Both aneurysms showed the highest WSS at an ostium. A bleb region in the BA tip and a dome region in the MCA aneurysm were consistently exposed to high WSS within a small local area with high spatial variation and little temporal change in comparison to other aneurysmal regions. High correlation was noted for the spatial distribution at the peak systole between the MR‐PC and the LDV studies, with the correlation coefficient value of 77% to 81%.

Conclusion

MR‐PC imaging showed good agreement with the reference LDV study, confirming its potential to study hemodynamics of physiologically realistic in vitro intracranial aneurysm models. Characteristic patterns of WSS, such as high spatial variation and absence of temporal variation, combined with locally increased high WSS as determined by MR‐PC imaging, may elucidate the effect of WSS on aneurysmal development and rupture. J. Magn. Reson. Imaging 2007;25:1120–1130. © 2007 Wiley‐Liss, Inc.
Soft‐tissue tumors evaluated by line‐scan diffusion‐weighted imaging: Influence of myxoid matrix on the apparent diffusion coefficient
Authors: Maeda Masayuki , Matsumine Akihiko , Kato Hiroya , Kusuzaki Katsuyuki , Maier Stephan E. , Uchida Atsumasa , Takeda Kan
Published: May 2007

Purpose

To compare the apparent diffusion coefficients (ADCs) of myxoid and nonmyxoid soft‐tissue tumors using line‐scan diffusion‐weighted imaging (LSDWI), and to investigate the myxoid matrix influence on ADCs of soft‐tissue tumors.

Materials and Methods

This study enrolled 44 patients with soft tissue tumors. They were divided into two groups: one with myxoid‐containing soft‐tissue tumors (N = 23) and the other with nonmyxoid soft‐tissue tumors (N = 21). The 44 patients were also classified histologically into 26 with malignant soft‐tissue tumors and 18 with benign soft‐tissue tumors. LSDWI was performed using b values of 5 and 1000 second/mm2. The ADCs of the tumors were calculated and compared for myxoid and nonmyxoid tumors and for benign and malignant tumors.

Results

The ADC (mean ± SD) was 1.92 ± 0.41 × 10–3 mm2/second in myxoid containing tumors, whereas the ADC was 0.97 ± 0.33 × 10–3 mm2/second in nonmyxoid tumors. The ADCs of the myxoid and nonmyxoid tumors were significantly different (P < 0.01). The ADCs were 1.45 ± 0.59 × 10–3 mm2/second in malignant tumors and 1.50 ± 0.64 × 10–3 mm2/second in benign tumors. The ADCs of benign and malignant soft‐tissue tumors were not significantly different.

Conclusion

The ADCs of myxoid‐containing soft‐tissue tumors were significantly higher than those of nonmyxoid soft‐tissue tumors. The myxoid matrix influences ADCs of both benign and malignant soft‐tissue tumors. J. Magn. Reson. Imaging 2007;25:1199–1204. © 2007 Wiley‐Liss, Inc.
Investigation of coil phase compensation in 3D imaging at very high acceleration factors
Authors: McDougall Mary Preston , Wright Steven M.
Published: May 2007

Purpose

To investigate the confounding effect of the coil phase in highly accelerated parallel imaging with small coils, contextualize the effect in terms of single‐echo acquisition (SEA) imaging, and show that it can be managed in the case of 3D imaging.

Materials and Methods

The effects of the coil phase variations in a 64‐channel array of surface microcoils were modeled. Fully encoded 64 × 128 × 64 (Nphase enc×Nreadout×Nslice enc) 3D data sets were obtained, from which factor of 64 accelerated 3D image sets (1 × 128 × 64 each) were extracted from single phase‐encoding lines, each representing a different phase compensation value.

Results

A comparison of the SEA images indicates that the choice of a compromise value for phase compensation successfully enabled a straightforward extension of SEA imaging to three dimensions. The use of the single compromise compensation value in the 3D acquisition resulted in a signal‐to‐noise ratio (SNR) penalty ranging from 6% to 41% through the slab when compared to the highest SNR possible using any phase compensation value.

Conclusion

The coil‐related phase shift issues inherent to highly accelerated imaging will require further study, but this work indicates the general nature of the problem and, more auspiciously, shows that it can be mitigated for at least this application. J. Magn. Reson. Imaging 2007;25:1305–1311. © 2007 Wiley‐Liss, Inc.
Creatine treatment promotes differentiation of GABA‐ergic neuronal precursors in cultured fetal rat spinal cord
Authors: Ducray Angélique D. , Schläppi Janine‐Ai , Qualls Rachel , Andres Robert H. , Seiler Rolf W. , Schlattner Uwe , Wallimann Theo , Widmer Hans Rudolf
Published: May 2007

Creatine is a substrate of cytosolic and mitochondrial creatine kinases. Its supplementation augments cellular levels of creatine and phosphocreatine, the rate of ATP resynthesis, and improves the function of the creatine kinase energy shuttle. High cytoplasmatic total creatine levels have been reported to be neuroprotective by inhibiting apoptosis. In addition, creatine has direct antioxidant effects, which may be of importance in amyotrophic lateral sclerosis. In the present study, we investigated the effects of creatine [5 mM] on survival and differentiation of cultured GABA‐immunoreactive (‐ir) and choline acetyltransferase (ChAT)‐ir rat spinal cord neurons. Furthermore, we addressed the neuroprotective potential of creatine supplementation against 3‐nitropropionic acid (3‐NP) induced toxicity. General cell survival and total neuronal cell density were not altered by chronic creatine treatment. We found, however, after chronic creatine and short‐term creatine exposure a significantly higher density of GABA‐ir neurons hinting to a differentiation‐inducing mechanism of creatine. This notion is further supported by a significant higher content of GAD after creatine exposure. Creatine supplementation also exerted a partial, but significant neuroprotection for GABA‐ir neurons against 3‐NP induced toxicity. Interestingly, chronic creatine treatment did not alter cell density of ChAT‐ir neurons but promoted their morphologic differentiation. Cell soma size and number of primary neurites per neuron were increased significantly after creatine supplementation. Taken together, creatine supplementation promoted the differentiation or the survival of GABAergic neurons and resulted in partial neuroprotection against 3‐NP induced toxicity. The data suggest that creatine may play a critical role during development of spinal cord neurons. © 2007 Wiley‐Liss, Inc.
Enhanced accumulation of phosphorylated α‐synuclein in double transgenic mice expressing mutant β‐amyloid precursor protein and presenilin‐1
Authors: Kurata Tomoko , Kawarabayashi Takeshi , Murakami Tetsuro , Miyazaki Kazunori , Morimoto Nobutoshi , Ohta Yasuyuki , Takehisa Yasushi , Nagai Makiko , Ikeda Masaki , Matsubara Etsuro , Westaway David , Hyslop Peter St. George , Harigaya Yasuo , Kamiya Tatsushi , Shoji Mikio , Abe Koji
Published: May 2007

A recent report showed that the accumulation of α‐synuclein (α‐syn) was detected in the brains of one‐third of Alzheimer's disease and Down syndrome patients. However, the relationship between amyloid‐β protein (Aβ) and α‐syn remains unclear. We analyzed the relation between the mutation of presenilin‐1 (PS‐1) and the pathological features of β‐amyloidosis and α‐synucleinopathy. We generated doubly transgenic mice overexpressing mutant β‐amyloid precursor protein (βAPP; Tg2576) and mutant PS‐1 (PS1L286Vtg; line 198) and analyzed 19 double Tg βAPP+/PS+ mice at 5–23 months (young to old), 23 age‐matched single Tg βAPP+/PS− mice, and 11 non‐Tg littermates. Immunohistochemical comparison was performed in these three groups by counting the area and the number of α‐syn‐ or phosphorylated α‐syn (pα‐syn)‐positive dystrophic neurites per plaque (ASPDN, pASPDN). The acceleration of Aβ pathology was found with earlier onset and exaggerated numbers in double Tg βAPP+/PS+ compared with single Tg βAPP+/PS− mouse brains. The accumulation of ASPDN and pASPDN was also accelerated in double Tg βAPP+/PS+ compared with single Tg βAPP+/PS− mouse brains, especially in pASPDN. The number and area of α‐syn and pα‐syn, and the ratio of pα‐syn positive neurites were significantly higher in double Tg βAPP+/PS+ than in single Tg βAPP+/PS− mouse brains in middle‐aged and old groups. Additional overexpression of mutant PS‐1 accelerated Aβ‐induced α‐synucleinopathy and further facilitated the phosphorylation of α‐syn, suggesting a direct association between mutant PS‐1 and phosphorylation of α‐syn. © 2007 Wiley‐Liss, Inc.
Dynamics of lactate concentration and blood oxygen level‐dependent effect in the human visual cortex during repeated identical stimuli
Authors: Mangia Silvia , Tkác̆ Ivan , Logothetis Nikos K. , Gruetter Rolf , Van de Moortele Pierre‐Francois , Uğurbil Kâmil
Published: May 2007

In vivo 1H NMR spectroscopy at 7 T was utilized to measure the changes in lactate concentration upon repeated identical visual stimuli, each lasting for 2 min. The average amplitude of these increases was found to be reduced over time (P < 0.01), from 0.13 ± 0.02 μmol/g during the first half of the stimulation paradigm, to 0.06 ± 0.02 μmol/g during the second half of the stimulation paradigm. In contrast, the blood oxygen level‐dependent (BOLD) effect on the fMRI water signal and on the height of the total creatine signal at 3.03 ppm was persistent during the whole observation period. This finding may suggest a differential adaptation of cortical output that is not reflected at the level of the global excitation‐inhibition activity of the cortical canonical circuits. Alternative possibilities that could account for an adaptation of [Lac] changes are also discussed. © 2007 Wiley‐Liss, Inc.
Rho‐kinase activation in endothelial cells contributes to expansion of infarction after focal cerebral ischemia
Authors: Yagita Yoshiki , Kitagawa Kazuo , Sasaki Tsutomu , Terasaki Yasukazu , Todo Kenichi , Omura‐Matsuoka Emi , Kaibuchi Kozo , Hori Masatsugu
Published: May 2007

Microcirculatory disturbances contribute to the expansion of infarct lesions after focal cerebral ischemia. Recently, it was shown that Rho‐kinase involves in endothelial dysfunction via down‐regulation of endothelial nitric oxide synthase function in a rodent stroke model. However, it is not clear whether endothelial Rho‐kinase is activated in vivo or Rho‐kinase activation contributes to microcirculatory disturbances after cerebral ischemia. In this study, we assessed the temporal and spatial profiles of Rho‐kianse activity and the effect of the Rho‐kinase inhibitor fasudil on microcirculatory disturbances in the focal brain ischemia. Rho‐kinase activation was evaluated by analyzing the phosphorylation of adducin, a substrate of Rho‐kinase, by immunohistochemistry. Staining for p‐adducin was found in endothelia in the ischemic area 6 hr after induction of ischemia. Microcirculatory disturbances and increased endothelial cell staining for von Willebrand factor (vWF) were observed in the same area. Postischemic treatment with fasudil suppressed endothelial Rho‐kinase activation, preserved microcirculation, and inhibited endothelial cell vWF staining. These effects resulted in inhibition of infarct expansion and improvement of neurologic deficits. These findings indicate that Rho‐kinase is activated in the endothelial cells and contributes to microcirculatory disturbances in cerebral ischemia. The vascular protective effect of Rho‐kinase inhibitors may be useful in the treatment of the acute phase of ischemic stroke. © 2007 Wiley‐Liss, Inc.
Aquaporin 9 changes in pyramidal cells before and is expressed in astrocytes after delayed neuronal death in the ischemic hippocampal CA1 region of the gerbil
Authors: Hwang In Koo , Yoo Ki‐Yeon , Li Hua , Lee Bong‐Hee , Suh Hong‐Won , Kwon Young‐Guen , Won Moo Ho
Published: May 2007

In the present study, we observed changes of aquaporin 9 (AQP9) in the hippocampus induced by 5 min of ischemia in gerbils. In sham‐operated animals, weak AQP9 immunoreactivity was detected in the stratum pyramidale of the hippocampus. AQP9 immunoreactivity, and its protein level in the CA1 region began to increase significantly at 6 hr and peaked 24 hr after ischemia. In the CA2/3 region, AQP9 immunoreactivity significantly increased at 12 hr after ischemia. Thereafter, AQP9 immunoreactivity in the hippocampus decreased continuously with time. From 4 days after ischemia, AQP9 immunoreactivity in the CA1 region was expressed and increased in glial components in the strata oriens and radiatum. Based on double‐immunofluorescence staining, many AQP9‐immunoreactive glial cells in the CA1 region were identified as astrocytes. In a reverse transcription‐polymerase chain reaction study, AQP9 mRNA levels significantly increased in the CA1 region at 6 hr after ischemia, and thereafter AQP9 mRNA levels decreased with time after ischemia. In addition, the water content in the gerbil hippocampus was highest 3 hr after ischemia/reperfusion; thereafter, water content in the ischemic hippocampus was higher than that in the sham‐operated group. This result shows how AQP9 in the gerbil hippocampus changes in neurons and is expressed in astrocytes before and after delayed neuronal death, respectively, after ischemia. These results indicate that changes in AQP9 in ischemic CA1 pyramidal cells may be related to delayed neuronal death and that the expression of AQP9 in astrocytes is related to gliosis in the CA1 region after transient forebrain ischemia. © 2007 Wiley‐Liss, Inc.