bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slow clearance gadolinium‐based extracellular and intravascular contrast media for three‐dimensional MR angiography
Authors: Bremerich Jens , Colet Jean Marie , Giovenzana Giovanni Battista , Aime Silvio , Scheffler Klaus , Laurent Sophie , Bongartz Georg , Muller Robert N. 
Published: August 2002

AbstractThe objective of this study was to assess two new slow‐clearance contrast media with extracellular and intravascular distribution for magnetic resonance angiography (MRA). Extracellular Gd‐DTPA‐BC2glucA and intravascular Gd(DO3A)3‐lys16 were developed within the European Biomed2 MACE Program and compared with two reference compounds, intravascular CMD‐A2‐Gd‐DOTA and extracellular GdDOTA, in 12 rats. Pre‐ and post‐contrast three‐dimensional MR (TR/TE = 5 msec/2.2 msec; isotropic voxel size 0.86 mm3) was acquired for 2 hours. Signal‐to‐noise enhancement (ΔSNR) was calculated. Two minutes after injection, all contrast media provided strong vascular signal enhancement. The ΔSNR for Gd‐DTPA‐BC2glucA, Gd(DO3A)3‐lys16, CMD‐A2‐Gd‐DOTA, and GdDOTA were 13.0 ± 1.8, 25.0 ± 3.2, 25.0 ± 4.0, and 18.0 ± 3.4, respectively. Gd‐DTPA‐BC2glucA, Gd(DO3A)3‐lys16, and CMD‐A2‐Gd‐DOTA cleared slowly from the circulation, whereas GdDOTA cleared rapidly. Vascular ΔSNR at 2 hours were 2.9 ± 0.6, 25.0 ± 3.2, 25.0 ± 4.0, and 0.4 ± 1.0. Gd(DO3A)3‐lys16 provided strong vascular and minor background enhancement, and thus may be useful for MRA or perfusion imaging. Gd‐DTPA‐BC2glucA produces persistent enhancement of extracellular water, and thus may allow quantification of extracellular distribution volume and assessment of myocardial viability. J. Magn. Reson. Imaging 2001;13:588–593. © 2001 Wiley‐Liss, Inc.
Gadolinium‐enhanced, vessel‐tracking, two‐dimensional coronary MR angiography: Single‐dose arterial‐phase vs. delayed‐phase imaging
Authors: Ho Vincent B. , Foo Thomas K. F. , Arai Andrew E. , Wolff Steven D. 
Published: August 2002

AbstractThe purposes of our study were to investigate the benefits of using a single dose of an extracellular contrast agent for coronary magnetic resonance angiography (CMRA) and to determine the relative benefits of arterial‐phase vs. delayed‐phase image acquisition. The right coronary artery was imaged in 10 healthy adults using a breath‐hold, two‐dimensional fast gradient echo pulse sequence designed for vessel tracking (multiphase, multislice image acquisition). Pre‐ and postcontrast CMRA was performed. Postcontrast imaging consisted of arterial‐ and delayed‐phase CMRA following a 15 mL bolus (single dose) of contrast media and of delayed‐phase imaging following a cumulative 45 mL contrast dose (triple dose). Contrast‐enhanced CMRA provided a significantly higher (P < 0.001) signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) than noncontrast CMRA. CNR was highest for single‐dose arterial‐phase CMRA (13.1 ± 4.5) and triple‐dose delayed‐phase CMRA (13.0 ± 4.8), followed by single‐dose delayed‐phase CMRA (8.4 ± 3.5) and noncontrast CMRA (4.2 ± 1.8). Single‐dose arterial‐phase CMRA provided the best visualization of the distal right coronary artery and was preferred for blinded physician assessments. We concluded that utilization of a single dose of extracellular contrast media improves CMRA, especially if timed for arterial‐phase imaging. J. Magn. Reson. Imaging 2001;13:682–689. © 2001 Wiley‐Liss, Inc.
Preferential arterial imaging using gated thick‐slice gadolinium‐enhanced phase‐contrast acquisition in peripheral MRA
Authors: Foo Thomas K.F. , Ho Vincent B. , Hood Maureen N. , Hess Sandra L. , Choyke Peter L. 
Published: August 2002

AbstractPurpose: To investigate the feasibility of preferential arterial imaging using gadolinium‐enhanced thick‐slice phase‐contrast imaging. Methods: Six healthy volunteers were studied using a peripheral‐gated segmented k‐space CINE phase‐contrast pulse sequence using four views per RR interval with flow encoding in the superior‐inferior direction. Images at the level of the popiteal trifurcation were acquired postcontrast with different section thicknesses (4–8 cm) and VENC values (20–150 cm/sec), and phase‐difference processing. Results: The post‐gadolinium contrast‐enhanced thick‐slice phase‐contrast acquisitions demonstrated the ability to visualize the tibio‐peroneal (trifurcation) arteries, especially in systole. With MR contrast agents, the signal from blood is raised significantly above that of stationary tissue from T1 shortening such that the partial volume artifact is reduced in thick‐slice acquisitions. Furthermore, by selecting the VENC value as a function of the cardiac cycle, the noise floor can be raised to selectively suppress flow values less than that of the noise threshold, allowing better accentuation of arterial structures at systole. Conclusions: Thick‐slice phase‐contrast acquisition with phase‐difference processing has been observed to reduce partial volume artifacts when an MR contrast agent substantially increases signal in the vasculature over that of normal background tissue. Preferential arterial images can be obtained by either increasing the VENC value to selectively suppress signal from slow flow in the veins or by subtracting the diastolic phase image from the peak systolic phase image. J. Magn. Reson. Imaging 2001;13:714–721. © 2001 Wiley‐Liss, Inc.
Tumor microvascular characterization using ultrasmall superparamagnetic iron oxide particles (USPIO) in an experimental breast cancer model
Authors: Turetschek Karl , Roberts Timothy P. L. , Floyd Eugenia , Preda Anda , Novikov Viktor , Shames David M. , Carter Wayne O. , Brasch Robert C. 
Published: August 2002

AbstractThe diagnostic potential of ultrasmall superparamagnetic iron oxide particles (USPIO) for quantitative tumor microvessel characterization was assessed by kinetic analysis of dynamic magnetic resonance imaging (MRI) in a rodent breast cancer model. Microvascular characteristics (transendothelial permeability (KPS) and fractional plasma volume (fPV)) were estimated in 32 female Sprague Dawley rats, bearing breast tumors of varying malignancy. These values were compared to a prototype macromolecular contrast medium standard, albumin‐(GdDTPA)30. Transendothelial permeability (KPS) correlated significantly (P < 0.05) with the tumor grade (Scarff‐Bloom‐Richardson (SBR) score) for the USPIO (r = 0.36), as well as for the reference macromolecule, albumin‐(GdDTPA)30 (r = 0.54). Estimates for the fPV did not show a statistically significant correlation with the tumor grade for either contrast medium. In conclusion, USPIO‐enhanced MRI data were capable to characterize tumor microvessel properties in this breast cancer model: microvascular permeability (determined using USPIO) correlated significantly with tumor grade. Thus, quantitative estimation of microvascular characteristics in tumors could provide a surrogate of new vessel formation (angiogenesis) and thus a further important clinical indication for USPIO, in addition to MR angiography. J. Magn. Reson. Imaging 2001;13:882–888. © 2001 Wiley‐Liss, Inc.
In vivo magnetic resonance (MR) study of fatty liver: Importance of intracellular ultrastructural alteration for MR tissue parameters change
Authors: Chai Jyh‐Wen , Lin Yung‐Chang , Chen Jeon‐Hor , Wu Chia‐Chin , Lee Chien‐Pei , Chu Woei‐Chyn , Lee San‐Kan 
Published: August 2002

AbstractFatty liver is thought to have a shorter T1 relaxation time than normal liver tissue, due to the accumulation of triglyceride. Previous studies regarding T1 and T2 relaxation times, however, show widely different results. In order to elucidate the mechanism responsible for the changes and diversity of relaxation times in fatty liver, we created two animal models in 14 rabbits, one acute form (N = 6) and the other chronic form (N = 8). Four rabbits were taken as a control group. Tissue relaxation times and the magnetization transfer (MT) effect of the liver tissue in these two models were measured. The results were correlated with biochemical analysis of water and fat content and histological examination, including findings in light microscopy and electron microscopy. Although the fatty ratio in both forms of fatty liver was similar, their tissue relaxation rate and MT effect were significantly different. The acute form showed prolongation of both T1 and T2 relaxation times (512 ± 51 msec vs. 710 ± 95 msec and 39 ± 1.8 msec vs. 48 ± 3.7 msec, respectively) and a decrease of the MT effect (50 ± 5.1% vs. 38 ± 6.3%), compared to those of the control group and preinduction liver. The chronic form showed shorter T1 and T2 values (526 ± 36 msec vs. 406 ± 56 msec and 36 ± 1.6 msec vs. 33 ± 2.3 msec, respectively) and a stronger MT effect (21 ± 0.9% vs. 26 ± 2.3%). In acute form fatty liver, electron microscopic examination revealed dramatic subcellular changes, such as vesicular transformation, a markedly increased amount of smooth endoplasmic reticulum (SER), and disruption of the crista. These changes were not found in the chronic form fatty liver. From this study, we concluded that the ultrastructural alteration in the subcellular organelles of hepatocyte might play a crucial role for the chameleonic presentation of MR tissue parameters in fatty liver. J. Magn. Reson. Imaging 2001;14:35–41. © 2001 Wiley‐Liss, Inc.
Cerebral hemodynamic changes measured by gradient‐echo or spin‐echo bolus tracking and its correlation to changes in ICA blood flow measured by phase‐mapping MRI
Authors: Marstrand Jacob R. , Rostrup Egill , Rosenbaum Sverre , Garde Ellen , Larsson Henrik B.W. 
Published: August 2002

AbstractChanges in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC‐MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase‐mapping. Also examined was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE‐EPI measured a significant increase in CBF and CBV in response to ACZ, while SE‐EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE‐EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE‐EPI and change in ICA flow. In conclusion, GE‐EPI under the present condition was superior to SE‐EPI in monitoring cerebral vascular changes.J. Magn. Reson. Imaging 2001;14:391–400. © 2001 Wiley‐Liss, Inc.
Uncommon presentation of a giant biliary cystadenoma: Correlation between MRI and pathologic findings
Authors: Frahm Christian , Zimmermann Arthur , Heller Martin , Brossmann Joachim 
Published: August 2002

AbstractAn uncommon case of a giant mucinous biliary cystadenoma (BCA) of the liver is described. On T2‐weighted and STIR images, a large hyperintense cystic mass revealed some septations and multiple intracystic masses of similar size and shape and uniform signal intensity, which was isointense to liver parenchyma. On T1‐weighted images, intracystic bodies were obscured and the cyst was hyperintense. The magnetic resonance (MR) appearance of intracystic fluid and structures was not due to mucinous or proteinous or hyperproteinous material, but corresponded to clots floating within hemorrhagic fluid. J. Magn. Reson. Imaging 2001;14:649–652. © 2001 Wiley‐Liss, Inc.
Accurate mass measurement of DNA oligonucleotide ions using high‐resolution time‐of‐flight mass spectrometry
Authors: Koomen John M. , Russell William K. , Tichy Shane E. , Russell David H. 
Published: August 2002

AbstractMatrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) time‐of‐flight mass spectrometry (TOFMS) play an essential role in the analysis of biological molecules, not only peptides and proteins, but also DNA and RNA. Tandem mass spectrometry used for sequence analysis has been a major focus of technological developments in mass spectrometry, but accurate mass measurements by high‐resolution TOFMS are equally important. This paper describes the role that high mass measurement accuracy can play in DNA composition assignment and discusses the influence of several parameters on mass measurement accuracy in both MALDI and ESI mass spectra. Five oligonucleotides (5–13mers) were used to test the resolving power and mass measurement accuracy obtained with MALDI and ESI instruments with reflectron TOF mass analyzers. The results from the experimental studies and additional theoretical calculations provide a basis to predict the practical utility of high‐resolution TOFMS for the analysis of larger oligonucleotides. Copyright © 2002 John Wiley & Sons, Ltd.
Molecular characterization of hepatitis C virus genotype 2a from the entire sequences of four isolates
Authors: Kurihara Chie , Ishiyama Narihiro , Nishiyama Yasumasa , Fukushi Shuetsu , Kageyama Tsutomu , Katayama Kazuhiko , Miura Soichiro 
Published: August 2002

AbstractGenotype 2a hepatitis C virus (HCV) has different characteristics from genotype 1b, such as responsiveness to interferon therapy. Such type‐specific characteristics appear to be due to differences in the HCV genome sequence. The complete sequences of genotype 2a HCV genome isolated from four patients with chronic hepatitis C were determined, and nucleotide and deduced amino acid sequences were compared within genotype 2a, as well as between genotype 2a and 1b. Whereas the amino acid sequence similarity of the core region was highest within genotype 1b, the NS3 and NS4B regions of exhibited greater similarity than the core region in genotype 2a. The serine protease and helicase motifs in the NS3 region were well conserved in genotype 2a to the same degree as in genotype 1b. However, the putative secondary structure of 2a isolates was significantly different from that of the 1b isolates. Analysis of amino acid similarity between genotypes 2a and 1b revealed the lowest degree of similarity in the E1 region, followed by the NS2 and NS5A region. Sequences of genotype 2a in the interferon‐sensitivity determining region (ISDR) located in the NS5A region had a deletion of four amino acids compared with that of genotype 1b. When the ISDR of the genotype 2a was aligned for maximal similarity, it exhibited similarity of only 52.5–55.0% when compared with that of HCV‐J, which belongs to genotype 1b. These findings for the entire sequences of genotype 2a isolates will contribute to virological studies of HCV. J. Med. Virol. 64:466–475, 2001. © 2001 Wiley‐Liss, Inc.
Coupled particle light scattering: a new technique for serodiagnosis of Epstein‐Barr virus infection
Authors: Baetens D.G.A. , Van Renterghem L.M.L. 
Published: August 2002

AbstractThe Coupled Particle Light Scattering™ technique was evaluated for serological diagnosis of Epstein‐Barr Virus (EBV) infection. Two hundred ninety‐six patient sera selected from several clinical categories (acute infection, non‐primary infection, interfering non‐EBV infection, non‐infected) were tested for IgM and IgG antibodies (anti‐VCA, anti‐EBNA and anti‐EA). Determination of EBV IgG with Copalis multiplex was accurate when compared with Enzygnost® Anti‐EBV/IgG ELISA. Although the sensitivity of Copalis IgM for acute infections was 100% a positive IgM result did not always indicate an acute infection. Strong reactivity to IgG EA (ratio 3, 1) and IgG VCA (ratio 13, 3) correlated with persistent infection or reactivation. The Copalis™I has many advantages over the existing methods, such as the possibility to measure three semi‐quantitative IgG responses to three different EBV antigens simultaneously. J. Med. Virol. 64:519–525, 2001. © 2001 Wiley‐Liss, Inc.
Ketogenic diet, amino acid metabolism, and seizure control
Authors: Yudkoff Marc , Daikhin Yevgeny , Nissim Ilana , Lazarow Adam , Nissim Itzhak 
Published: August 2002

AbstractThe ketogenic diet has been utilized for many years as an adjunctive therapy in the management of epilepsy, especially in those children for whom antiepileptic drugs have not permitted complete relief. The biochemical basis of the dietary effect is unclear. One possibility is that the diet leads to alterations in the metabolism of brain amino acids, most importantly glutamic acid, the major excitatory neurotransmitter. In this review, we explore the theme. We present evidence that ketosis can lead to the following: 1) a diminution in the rate of glutamate transamination to aspartate that occurs because of reduced availability of oxaloacetate, the ketoacid precursor to aspartate; 2) enhanced conversion of glutamate to GABA; and 3) increased uptake of neutral amino acids into the brain. Transport of these compounds involves an uptake system that exchanges the neutral amino acid for glutamine. The result is increased release from the brain of glutamate, particularly glutamate that had been resident in the synaptic space, in the form of glutamine. These putative adaptations of amino acid metabolism occur as the system evolves from a glucose‐based fuel economy to one that utilizes ketone bodies as metabolic substrates. We consider mechanisms by which such changes might lead to the antiepileptic effect. © 2001 Wiley‐Liss, Inc.
Metabolic approach of absence seizures in a genetic model of absence epilepsy, the GAERS: Study of the leucine‐glutamate cycle
Authors: Dufour Franck , Nalecz Katarzyna A. , Nalecz Maciej J. , Nehlig Astrid 
Published: August 2002

AbstractWe suggest that a dysregulation of energy metabolism in the brain of genetic absence epilepsy rats from Strasbourg (GAERS) could create a specific cerebral environment that would favor the expression of spike‐and‐wave discharges (SWD) in the thalamocortical loop, largely dependent on glutamatergic and γ‐aminobutyric acid (GABA)‐ergic neurotransmissions. We tested several aspects of metabolic activity in the brain of GAERS compared to a genetic strain of nonepileptic (NE) rats. Glucose metabolism was higher in all brain regions of GAERS compared to those of NE rats along the whole glycolytic and aerobic pathways, as assessed by regional histochemical measurement of lactate dehydrogenase and cytochrome oxidase activities. Branched‐chain amino acids (BCAA) and α‐ketoisocaproate (α‐KIC), the ketoacid of leucine, when injected intraperitoneally, increased the number of SWD in GAERS but had only a slight effect on their duration. These data speak in favor of a BCAA‐ or α‐KIC‐induced change in neuronal excitability. Leucine and α‐KIC decreased the concentration of glutamate in thalamus and cortex without affecting GABA concentrations. Thus, BCAA and α‐KIC, by decreasing glutamatergic neurotransmission, could favor GABAergic neurotransmission, which is known to increase the occurrence of seizures in GAERS. Finally, the transport of [1‐14C]α‐KIC in freshly isolated cortical neurons was lower in GAERS than in NE rats, and this difference was shown to be of metabolic origin. The addition of gabapentin, a specific inhibitor of BCAA transaminase (BCAT), reduced the transport of [1‐14C]α‐KIC in GAERS and NE rats to a level that became identical in both strains. This strain‐dependent change was not related to a difference in the activity of BCAT, which was identical in GAERS and NE rats. The exact origin of this apparent metabolic dysregulation of energy metabolism in GAERS that could underlie the origin of seizures in that strain remains to be explored further. © 2001 Wiley‐Liss, Inc.
Constitutive expression of heterologous N‐methyl‐D‐aspartate receptor subunits in rat adrenal medulla
Authors: Hinoi Eiichi , Fujimori Sayumi , Nakamura Yoichi , Balcar Vladimir J. , Kubo Keita , Ogita Kiyokazu , Yoneda Yukio 
Published: August 2002

AbstractAn RT‐PCR analysis revealed constitutive expression of mRNA for N‐methyl‐D‐aspartate (NMDA) receptor (NR)‐1, NR‐2C, and NR‐2D subunits in rat adrenal and pituitary glands, in addition to brain and retina. Constitutive expression of mRNA was detected for the NR‐2A subunit in pituitary but not adrenal gland. Although on Western blotting assays adrenal medulla exhibited expression of NR‐1 subunit protein without expression of NR‐2C and NR‐2D subunit proteins, an immunohistochemical investigation clearly showed selective localization of proteins for NR‐1, NR‐2C, and NR‐2D subunits in adrenal medulla but not in adrenal cortex. Prior treatment with different glycosidases invariably resulted in a marked increase in immunoreactivity to the anti‐NR‐1 antibody in both hippocampus and adrenal medulla. An intraperitoneal injection of a blocker of NMDA receptor channel, but not NMDA itself, led to marked potentiation of DNA binding activity of the transcription factor activator protein‐1 in adrenal nuclear extracts 2 hr after administration. These results suggest that heteromeric NMDA receptor channels may be constitutively and functionally expressed with glycosylation of NR‐1 subunit under the influence of tonic stimulation by circulating agonists such as L‐glutamate in rat adrenal medulla. © 2002 Wiley‐Liss, Inc.
Rev‐erbα gene expression in the mouse brain with special emphasis on its circadian profiles in the suprachiasmatic nucleus
Authors: Onishi Hiroyasu , Yamaguchi Shun , Yagita Kazuhiro , Ishida Yoshiki , Dong Xin , Kimura Hidehito , Jing Zhang , Ohara Hidefumi , Okamura Hitoshi 
Published: August 2002

AbstractRev‐erbα is an orphan nuclear receptor that constitutively suppresses gene transcription. In the present study, the expression of Rev‐erbα was investigated in the mouse brain by in situ hybridization using antisense cRNA probe. Positive Rev‐erbα mRNA signals were detected widely in the brain with the highest expression in the suprachiasmatic nucleus (SCN). In the constant dark condition, the circadian expression profiles of Rev‐erbα m RNA in the SCN showed a peak at early daytime (CT4) and a trough at early night time (CT16). The environmental lighting condition (light–dark environmental condition and exposure in the subjective night) did not alter the expression profiles. These findings indicate that Rev‐erbα gene is a transcription factor intimately related to the circadian clock in the SCN. © 2002 Wiley‐Liss, Inc.
Alterations in myelination in the central nervous system of dystonia musculorum mice
Authors: Saulnier Ron , De Repentigny Yves , Yong Voon Wee , Kothary Rashmi 
Published: August 2002

AbstractDystonia musculorum (dt) is an autosomal recessive sensory neuropathy in mice resulting from a mutation in the gene encoding the cytoskeletal linker protein Bpag1. In addition to neurodegeneration, dt mice display myelination abnormalities in the peripheral nervous system. In this report we investigated whether myelination abnormalities are also present in the central nervous system of dtTg4 mice. Transcripts for both neural isoforms of Bpag1 (a1 and a2) were detected in optic nerves and spinal cords of wild‐type mice. Light microscopy of resin‐embedded thin sections revealed a reduction in myelinated axons in both optic nerves and spinal cords in dtTg4 mice. As well, hypermyelinated axons were detected in these tissues. Ultrastructural analysis of optic nerves and spinal cords from dtTg4 mice revealed an increase in the number of amyelinated axons, the presence of hypo‐ and hypermyelinated axons, and redundant myelin that course away from axons. Changes in the level of myelin proteins accompanied the morphological alterations. Myelin‐associated glycoprotein levels were reduced in optic nerves of dtTg4 mice, and myelin basic protein levels were altered in optic nerves, sciatic nerves, and spinal cords of affected mice. Short‐term cultures of oligodendrocytes derived from dtTg4 mice did not show morphological alterations. © 2002 Wiley‐Liss, Inc.