bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hyperglycemia‐induced apoptotic cell death in the mouse blastocyst is dependent on expression of p53
Authors: Keim April L. , Chi Maggie M.‐Y. , Moley Kelle H. 
Published: August 2002

AbstractMurine preimplantation embryos exposed to hyperglycemia experience decreased glucose transport, and overexpression of the proapoptotic protein BAX, leading to increased apoptosis. These changes may account for the increased rates of miscarriages and malformations seen in women with diabetes mellitus. To test whether p53 expression is necessary for hyperglycemia‐induced apoptosis, p53+/+, +/−, −/− embryos were obtained by superovulation. Two‐cell embryos were cultured to a blastocyst stage in 52 mM d‐ or l‐glucose. Apoptosis was detected using terminal dUTP nick end labeling (TUNEL) assays. In vivo studies were performed in the same manner using blastocysts recovered from streptozotocin‐induced diabetic mothers. Both in vitro and in vivo studies showed that wildtype embryos had a significantly higher percentage of TUNEL‐positive nuclei than p53+/− and −/− embryos. To test whether p53 is upstream of BAX, immunofluorescent confocal microscopy and immunoprecipitation/ immunoblotting were performed on blastocysts cultured in high vs. control glucose conditions. Blastocysts from p53+/+ mice exhibited increased BAX staining vs. p53+/− and −/− embryos. Next, to determine whether a decrease in glucose transport was upstream or downstream of p53, deoxyglucose transport was measured in individual blastocysts from p53+/+ and +/− diabetic vs. nondiabetic mice. Embryos from diabetic p53+/− mice exhibit a 44% decrease in glucose transport, similar to the 38% decrease seen in embryos from diabetic p53+/+ mice. Taken together, these results strongly indicate that p53 plays a role in hyperglycemia‐induced apoptosis, upstream of BAX overexpression and downstream of the decrease in glucose transport experienced by the mouse preimplantation embryo. Mol. Reprod. Dev. 60: 214–224, 2001. © 2001 Wiley‐Liss, Inc.
Control and expression of cystatin C by mouse decidual cultures
Authors: Afonso Suzanne , Tovar Chris , Romagnano Linda , Babiarz Bruce 
Published: August 2002

AbstractDuring mouse embryo implantation, trophoblast invasion is controlled in part by a balance of trophoblast‐derived proteinases and uterine decidual proteinase inhibitors. Our work has focused on cystatin C, the secreted inhibitor of cathepsins B and L. We have previously shown that cystatin C is synthesized by the uterine decidua and localized to the cells in close contact with the trophoblast during implantation in vivo. In the work reported here we have established that decidualizing cultures show a similar upregulation of cystatin C. Using Northern and Western blotting and immunolocalization techniques both cystatin C mRNA and secreted protein increased with the morphological differentiation of stromal or decidual capsule cultures. In an effort to understand the regulation of cystatin C expression, decidual cells were analyzed under various culture conditions. Cystatin C expression was upregulated by increased cell density and by the presence of serum in the media. The growth factors TGF‐β1 and EGF were found to induce cystatin C to levels comparable to serum stimulation. Co‐culture with ectoplacental cones (EPCs) likewise induced expression and resulted in the localization of cystatin at the decidua:trophoblast interface. This work shows that decidualizing cultures are a good system to study cystatin C expression and that the expression is controlled in part by TGF‐β1 and EGF signaling. Mol. Reprod. Dev. 61: 155–163, 2002. © 2002 Wiley‐Liss, Inc.
Disorders of glutamate metabolism
Authors: Kelly Andrea , Stanley Charles A. 
Published: August 2002

AbstractThe significant role the amino acid glutamate assumes in a number of fundamental metabolic pathways is becoming better understood. As a central junction for interchange of amino nitrogen, glutamate facilitates both amino acid synthesis and degradation. In the liver, glutamate is the terminus for release of ammonia from amino acids, and the intrahepatic concentration of glutamate modulates the rate of ammonia detoxification into urea. In pancreatic β‐cells, oxidation of glutamate mediates amino acid‐stimulated insulin secretion. In the central nervous system, glutamate serves as an excitatory neurotransmittor. Glutamate is also the precursor of the inhibitory neurotransmittor GABA, as well as glutamine, a potential mediator of hyperammonemic neurotoxicity. The recent identification of a novel form of congenital hyperinsulinism associated with asymptomatic hyperammonemia assigns glutamate oxidation by glutamate dehydrogenase a more important role than previously recognized in β‐cell insulin secretion and hepatic and CNS ammonia detoxification. Disruptions of glutamate metabolism have been implicated in other clinical disorders, such as pyridoxine‐dependent seizures, confirming the importance of intact glutamate metabolism. This article will review glutamate metabolism and clinical disorders associated with disrupted glutamate metabolism. MRDD Research Reviews 2001;7:287–295. © 2001 Wiley‐Liss, Inc.
Multifunctional interventional devices for MRI: A combined electrophysiology/MRI catheter
Authors: Susil Robert C. , Yeung Christopher J. , Halperin Henry R. , Lardo Albert C. , Atalar Ergin 
Published: August 2002

AbstractThe design and application of a two‐wire electrophysiology (EP) catheter that simultaneously records the intracardiac electrogram and receives the MR signal for active catheter tracking is described. The catheter acts as a long loop receiver, allowing for visualization of the entire catheter length while simultaneously behaving as a traditional two‐wire EP catheter, allowing for intracardiac electrogram recording and ablation. The application of the device is demonstrated by simultaneously tracking the catheter and recording the intracardiac electrogram in canine models using 7 and 10 frame/sec real‐time imaging sequences. Using solely MR imaging, the entire catheter was visualized and guided from the jugular vein into the cardiac chambers, where the intracardiac electrogram was recorded. By combining several functions in a single, simple structure, the excellent tissue contrast and functional imaging capabilities of MR can be used to improve the efficacy of EP interventions. This catheter will facilitate MR‐guided interventions and demonstrates the design of multifunctional interventional devices for use in MRI. Magn Reson Med 47:594–600, 2002. © 2002 Wiley‐Liss, Inc.
Rapid T1 mapping using multislice echo planar imaging
Authors: Clare Stuart , Jezzard Peter 
Published: August 2002

AbstractDetermination of neurological pathology in white matter disease can be made in a semiquantitative way from T1‐ or T2‐weighted images. A higher level of quantification based on measured T1 or T2 values has been either limited to specific regions of interest or to low‐resolution maps. Higher‐resolution T1 maps have proved difficult to obtain due to the excessively long scan times required using conventional techniques. In this study, clinically acceptable images are obtained by using single‐shot echo planar imaging (EPI) with an acquisition scheme that maximizes signal‐to‐noise while minimizing the scan time. Magn Reson Med 45:630–634, 2001. © 2001 Wiley‐Liss, Inc.
Parahydrogen‐induced polarization in imaging: Subsecond 13C angiography
Authors: Golman K. , Axelsson O. , Jóhannesson H. , Månsson S. , Olofsson C. , Petersson J.S. 
Published: August 2002

AbstractHigh nuclear spin polarization of 13C was reached in organic molecules. Enhancements of up to 104, compared to thermal polarization at 1.5 T, were achieved using the parahydrogen‐induced polarization technique in combination with a field cycling method. While parahydrogen has no net polarization, it has a high spin order, which is retained when hydrogen is incorporated into another molecule by a chemical reaction. By subjecting this molecule to a sudden change of the external magnetic field, the spin order is transferred into net polarization. A 13C angiogram of an animal was generated in less than a second. Magn Reson Med 46:1–5, 2001. © 2001 Wiley‐Liss, Inc.
A serial MR study of cerebral blood flow changes and lesion development following endothelin‐1‐induced ischemia in rats
Authors: Biernaskie Jeff , Corbett Dale , Peeling James , Wells Jennifer , Lei Hao 
Published: August 2002

AbstractThe vasoconstrictive peptide endothelin‐1 (ET‐1) has been used previously to transiently occlude the middle cerebral artery (MCA) in rats. However, the duration of the resulting reduction in cerebral blood flow (CBF) and the reperfusion characteristics are poorly understood. In this study perfusion and T2‐weighted MRI were used together with histology to characterize the cerebral perfusion dynamics and lesion development following ET‐1 injection. Twenty‐two rats received an intracerebral injection of ET‐1 adjacent to the MCA. CBF was reduced to 30–50% of control levels, and a significant reduction persisted for 16 h in the cortex and 7 h in the striatum. The lesion size measured by T2‐weighted imaging at 48 h correlated with the final infarct size measured by histology at 7 d. The sustained reduction in CBF and the gradual development of the ischemic lesion resemble human stroke evolution, suggesting that this model may be useful for evaluating therapeutic agents, particularly when treatment is delayed. Magn Reson Med 46:827–830, 2001. © 2001 Wiley‐Liss, Inc.
Dualband spectral‐spatial RF pulses for prostate MR spectroscopic imaging
Authors: Schricker Amir A. , Pauly John M. , Kurhanewicz John , Swanson Mark G. , Vigneron Daniel B. 
Published: August 2002

AbstractAlthough MR spectroscopic imaging (MRSI) of the prostate has demonstrated clinical utility for the staging and monitoring of cancer extent, current acquisition methods are often inadequate in several aspects. Conventional 180° pulses can suffer from chemical shift misregistration, and have high peak‐power requirements that can exceed hardware limits in many prostate MRSI studies. Optimal water and lipid suppression are also critical to obtain interpretable spectra. While complete suppression of the periprostatic lipid resonance is desired, controlled partial suppression of water can provide a valuable phase and frequency reference for data analysis and an assessment of experimental success in cases in which all other resonances are undetectable following treatment. In this study, new spectral‐spatial RF pulses were developed to negate chemical shift misregistration errors and to provide dualband excitation with partial excitation of the water resonance and full excitation of the metabolites of interest. Optimal phase modulation was also included in the pulse design to provide 40% reduction in peak RF power. Patient studies using the new pulses demonstrated both feasibility and clear benefits in the reliability and applicability of prostate cancer MRSI. Magn Reson Med 46:1079–1087, 2001. © 2001 Wiley‐Liss, Inc.
Noninvasive quantification of total sodium concentrations in acute reperfused myocardial infarction using 23Na MRI
Authors: Constantinides Chris D. , Kraitchman D.L. , O'Brien K.O. , Boada F.E. , Gillen J. , Bottomley Paul A. 
Published: August 2002

AbstractThe transport of sodium and potassium between the intra‐ and extracellular pools and the maintenance of the transmembrane concentration gradients are important to cell function and integrity. The early disruption of the sodium pump in myocardial infarction in response to the exhaustion of energy reserves following ischemia and reperfusion results in increased intracellular (and thus total) sodium levels. In this study a method for noninvasively quantifying myocardial sodium levels directly from sodium (23Na) MRI is presented. It was used to measure total myocardial sodium on a clinical 1.5T system in six normal dogs and five dogs with experimentally‐induced myocardial infarction (MI). The technique was validated by comparing total sodium content measured by 23Na MRI with that measured by atomic absorption spectrophotometry (AAS) in biopsied tissue. Total sodium measured by 23Na MRI was significantly elevated in regions of infarction (81.3 ± 14.3 mmol/kg wet wt, mean ± SD) compared to noninfarcted myocardial tissue from both infarcted dogs (36.2 ± 1.1, P < 0.001) and from normal controls (34.4 ± 2.8, P < 0.0001). Myocardial tissue sodium content as measured by 23Na MRI did not vary regionally in the lateral, anterior, or inferior regions in normal hearts (ANOVA, P = NS). Sodium content measured by 23Na MRI agreed with the mean AAS estimates of 31.3 ± 5.6 mmol/kg wet wt (P = NS) in normal hearts, and did not differ significantly from AAS measurements in MI (P = NS). Thus, local tissue sodium levels can be accurately quantified noninvasively using 23Na MRI in normal and acutely reperfused MI. The detection of regional myocardial sodium elevations may help differentiate viable from nonviable, infarcted tissue. Magn Reson Med 46:1144–1151, 2001. © 2001 Wiley‐Liss, Inc.
Delay in initiation and termination of muscle contraction, motor impairment, and physical disability in upper limb hemiparesis
Authors: Chae John , Yang Guang , Park Byung Kyu , Labatia Ihab 
Published: August 2002

AbstractThe purpose of this study was to describe the relationship between the delay in initiation and termination of muscle contraction and clinical measures of motor impairment and physical disability in the affected upper limb of patients with hemiparesis. Electromyographic (EMG) activity of 26 long‐term survivors of stroke was recorded during isometric wrist flexion and extension. Upper limb motor impairment and disability were assessed with the Fugl‐Meyer motor assessment (FMA) and arm motor ability test (AMAT), respectively. Delay in initiation and termination of muscle contraction was significantly prolonged in the paretic arm. However, the delay was not significantly affected by stroke type, stroke level, side of hemiparesis, or presence of aphasia. Delay in initiation and termination of muscle contraction correlated significantly with FMA and AMAT. Abnormally delayed initiation and termination of muscle contraction may contribute to hemiparetic upper limb motor impairment and physical disability in hemiparetic patients. © 2002 Wiley Periodicals, Inc. 25: 000–000, 2002
Treatment experience in patients with anti–myelin‐associated glycoprotein neuropathy
Authors: Gorson Kenneth C. , Ropper Allan H. , Weinberg David H. , Weinstein Robert 
Published: August 2002

AbstractWe report our experience with 24 consecutively treated patients (15 men and 9 women, median age 64 years) with anti–myelin‐associated glycoprotein (anti‐MAG) neuropathy. The rates of response to plasma exchange (40%), immune globulin (16%), and cyclophosphamide‐based therapy (36%) were similar. Five (24%) responded to the first treatment modality, 32% to a second, alternative modality, and 31% to a third. Only 4 of 12 responders had sustained improvement; the others relapsed after a median of 7 months. In those 4 patients, the median immunoglobulin M (IgM) level dropped by 25% compared to an increase of 24% in the nonresponders (P = 0.04). Thus, most patients with anti‐MAG neuropathy failed to have sustained improvement after treatment, and none of the therapies emerged as superior. Disability improved transiently after therapy in approximately 50% of cases. A 25% reduction of the IgM level predicted sustained improvement, but was difficult to achieve. There were no clinical or electrodiagnostic features associated with a treatment response, nor did a reduction of the anti‐MAG antibody titer correlate with clinical improvement. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 778–786, 2001
Brachial plexus involvement as the only expression of hereditary neuropathy with liability to pressure palsies
Authors: Ørstavik Kristin , Skard Heier Mona , Young Peter , Stögbauer Florian 
Published: August 2002

AbstractHereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal‐dominant focal neuropathy characterized by recurrent entrapment neuropathies. Single members of families with HNPP and brachial plexus involvement have been reported previously. We describe a family with three affected members and in which the only symptom of entrapment was recurrent brachial plexopathy. The diagnosis of HNPP in this family was confirmed by both neurophysiological methods and DNA analysis. The distinction between HNPP and hereditary neuralgic amyotrophy is discussed. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1093–1096, 2001
Changes in glycolytic network and mitochondrial design in creatine kinase–deficient muscles
Authors: de Groof Ad J. C. , Oerlemans Frank T. J. J. , Jost Carolina R. , Wieringa Bé 
Published: August 2002

AbstractSkeletal muscles respond with high plasticity to pathobiological conditions or changes in physiological demand by remodeling cytoarchitectural and metabolic characteristics of individual myocytes. We have previously shown that muscles of mice without mitochondrial and/or cytosolic creatine kinases (ScCKmit−/− and/or M‐CK−/−) partly compensate for the defect(s) by redirecting metabolic pathways and ultrastructural characteristics. Here, we show by semiquantitative Western blot analysis that the compensatory changes involve mutation‐ and fiber‐type–specific coordinated regulation of divergent but functionally coupled groups of proteins. Fast‐twitch gastrocnemius muscle of CK−−/−− mice display a two‐ to fourfold upregulation of mitochondrial cytochrome c oxidase, inorganic phosphate carrier, adenine nucleotide translocator, and voltage‐dependent anion channel proteins. In parallel, cytosolic myoglobin is upregulated. Slow‐twitch soleus muscle responds with changes in the glycolytic enzyme pattern, including a shift in lactate dehydrogenase isoenzyme composition. Adaptations in the network for oxidative adenosine triphosphate (ATP) production are already apparent at 17 days of age. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1188–1196, 2001
Magnetic resonance imaging of denervation‐induced muscle atrophy: Effects of clenbuterol in the rat
Authors: Cockman Michael D. , Jones Melissa B. , Prenger Marla C. , Sheldon Russell J. 
Published: August 2002

AbstractWe show that magnetic resonance imaging (MRI) can be used to quantify the amount of muscle in the lower legs of adult rats and to noninvasively monitor the onset and progression of denervation‐induced atrophy. Muscle cross‐sectional areas determined from 2D gradient‐echo MR images allow longitudinal quantification of the protective effects of a β2‐adrenergic agonist clenbuterol. We also show that the estimation of clenbuterol's efficacy is improved by computation of the muscle volume. Rapid animal throughput and the ability to accurately estimate efficacy make MRI an attractive technology for studying skeletal muscle atrophy and hypertrophy, allowing the evaluation of potential therapies in longitudinal studies. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1647–1658, 2001
Load transfer approach for laterally loaded piles
Authors: Guo Wei Dong , Lee F. H. 
Published: August 2002

AbstractA two‐parameter model has been proposed previously for predicting the response of laterally loaded single piles in homogenous soil. A disadvantage of the model is that at high Poisson's ratio, unreliable results may be obtained. In this paper, a new load transfer approach is developed to simulate the response of laterally loaded single piles embedded in a homogeneous medium, by introducing a rational stress field. The approach can overcome the inherent disadvantage of the two‐parameter model, although developed in a similar way. Generalized solutions for a single pile and the surrounding soil under various pile‐head and base conditions were established and presented in compact forms. With the solutions, a load transfer factor, correlating the displacements of the pile and the soil, was estimated and expressed as a simple equation. Expressions were developed for the modulus of subgrade reaction for a Winkler model as a unique function of the load transfer factor. Simple expressions were developed for estimating critical pile length, maximum bending moment, and the depth at which the maximum moment occurs. All the newly established solutions and/or expressions, using the load transfer factor, offer satisfactory predictions in comparison with the available, more rigorous numerical approaches. The current solutions are applicable to various boundary conditions, and any pile–soil relative stiffness. Copyright © 2001 John Wiley & Sons, Ltd.
Experimental analysis of compaction of concrete and mortar
Authors: Burlion Nicolas , Pijaudier‐Cabot Gilles , Dahan Noël 
Published: August 2002

AbstractCompaction of concrete is physically a collapse of the material porous microstructure. It produces plastic strains in the material and, at the same time, an increase of its bulk modulus. This paper presents two experimental techniques aimed at obtaining the hydrostatic response of concrete and mortar. The first one is a uniaxial confined compression test which is quite simple to implement and allows to reach hydrostatic pressures of about 600 MPa. The specimen size is large enough so that concrete with aggregate sizes up to 16 mm can be tested. The second one is a true hydrostatic test performed on smaller (mortar) specimens. Test results show that the hydrostatic response of the material is elasto‐plastic with a stiffening effect on both the tangent and unloading bulk moduli. The magnitude of the irreversible volumetric strains depends on the initial porosity of the material. This porosity can be related in a first approximation to the water/cement ratio. A comparison of the hydrostatic responses obtained from the two testing techniques on the same material show that the hydrostatic response of cementitious materials cannot be uncoupled from the deviatoric response, as opposed to the standard assumption in constitutive relations for metal alloys. This feature should be taken into account in the development of constitutive relations for concrete subjected to high confinement pressures which are needed in the modelling of impact problems. Copyright © 2001 John Wiley & Sons, Ltd.
Dynamic interaction between the soil and an anchored sheet pile during seismic excitation
Authors: Degrande G. , Praet E. , Van Zegbroeck B. , Van Marcke P. 
Published: August 2002

AbstractA subdomain approach for dynamic soil–structure interaction is proposed for the linear elastic seismic analysis of an anchored sheet pile, retaining a horizontally layered soil on rigid bedrock. A hybrid solution technique is used, employing a finite element formulation for the generalized sheet pile, a thin layer formulation for the soil and a direct stiffness formulation for the tieback; the displacement vectors of the sheet pile and the soil are decomposed, using the eigenmodes of the sheet pile and the propagating or decaying modes in the soil. The discretization can be limited to the interface(s), where pointwise continuity of the displacements is enforced, whereas a weak variational formulation is used for the stress equilibrium. The solution technique is illustrated by means of a numerical example, where the harmonic response of a flexible anchored sheet pile is considered and compared to the case where no tieback is present. Copyright © 2002 John Wiley & Sons, Ltd.