bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiation of nonmetastatic and metastatic rodent prostate tumors with high spectral and spatial resolution MRI
Authors: Fan Xiaobing , River Jonathan N. , Zamora Marta , Tarlo Kirk , Kellar Kenneth , Rinker‐Schaeffer Carrie , Gregory S. Karczmar  
Published: August 2002

AbstractMR images can be acquired with high spectral and spatial resolution to precisely measure lineshapes of the water and fat resonances in each image voxel. Previous work suggests that the high‐resolution spectral information can be used to improve image contrast, SNR, sensitivity to contrast agents and to physiologic and biochemical processes that affect local magnetic susceptibility gradients. The potential advantages of high‐resolution spectroscopic imaging (SI) suggest that it might be useful for early detection and characterization of tumors. The present experiments evaluate the use of high‐resolution SI to discriminate between metastatic and nonmetastatic rodent Dunning prostate tumors. SI datasets were obtained at 4.7 Tesla with an in‐plane resolution of 350–500 μ in a single 1.0‐mm slice, and 6–8 Hz spectral resolution, before and after i.v. injection of an iron oxide contrast agent. Images of water signal peak height in nonmetastatic tumors were smoother in the tumor interior than images of metastatic tumors (P < .004 by t‐test) before contrast media injection. This difference was stronger in contrast‐enhanced images (P < .0004). In addition, the boundary between the tumor and muscle was more clearly demarcated in nonmetastatic than metastatic tumors. Combinations of image texture, tumor edge morphology, and changes in T following contrast media injection improved discrimination between metastatic and nonmetastatic tumors. The data presented here do not demonstrate that effective discrimination between metastatic and nonmetastatic tumors depends on the use of high‐resolution SI. However, the results suggest that SI and/or other MR methods that provide similar contrast might be used clinically for early and accurate detection of metastatic disease. Magn Reson Med 45:1046–1055, 2001. © 2001 Wiley‐Liss, Inc.
Differential routing of choline in implanted breast cancer and normal organs
Authors: Katz‐Brull R. , Margalit R. , Degani H. 
Published: August 2002

AbstractCholine is an essential nutrient participating as the initial substrate in major metabolic pathways. The differential metabolic routing of choline was investigated in MCF7 human breast cancer implanted in nude mice and in the kidney, liver, and brain of these mice. The distribution of metabolites following infusion of [1,2‐13C]‐choline was monitored by 13C magnetic resonance spectroscopy. This infusion led to an 18‐fold increase in plasma choline and to concomitant changes in the content and distribution of choline metabolites. In vivo kinetic studies of the tumor during the infusion demonstrated accumulation of choline in the interstitium and intracellular synthesis of phosphocholine. The amount of unlabeled choline metabolites was 7.1, 4.1, 3.5, and 1.4 μmol/g in the kidney, liver, tumor, and brain, respectively. The variations in the labeled metabolites were more pronounced with high amounts in the kidney and liver (8.0 and 4.3 μmol/g, respectively) and very low amounts in the tumor and brain (0.33 and 0.12 μmol/g, respectively). In the kidney and liver, betaine (unlabeled and labeled) was the predominant choline metabolite. The dominant unlabeled metabolite in breast cancer was phosphocholine and in the brain glycerophosphocholine. Magn Reson Med 46:31–38, 2001. © 2001 Wiley‐Liss, Inc.
Quantitative 1H magnetic resonance spectroscopy of myoglobin de‐ and reoxygenation in skeletal muscle: Reproducibility and effects of location and disease
Authors: Kreis R. , Bruegger K. , Skjelsvik C. , Zwicky S. , Ith M. , Jung B. , Baumgartner I. , Boesch C. 
Published: August 2002

Abstract1H‐magnetic resonance spectroscopy (1H‐MRS) of deoxymyoglobin (DMb) provides a means to noninvasively monitor the oxygenation state of human skeletal muscle in work and disease. As shown in this work, it also offers the opportunity to measure the absolute tissue content of DMb, the basic oxygen consumption of resting muscle, and the reperfusion characteristics after release of a pressure cuff. The methodology to determine these tissue properties simultaneously at two positions along the calf is presented. The obtained values are in agreement with invasive determinations. The reproducibility of the 1H‐MRS measurements is established for healthy controls and patients with peripheral arterial disease (PAD). A location dependence in axial direction, as well as differences between controls and patients are demonstrated for all parameters. The reoxygenation time in particular is expected to provide a means to quantitatively monitor therapies aimed at improving muscular perfusion in these patients. Magn Reson Med 46:240–248, 2001. © 2001 Wiley‐Liss, Inc.
Design of a logarithmic k‐space spiral trajectory
Authors: Cline Harvey E. , Zong Xuli , Gai Neville 
Published: August 2002

AbstractSpiral acquisitions are used in fast cardiac imaging because they traverse k‐space efficiently and minimize flow artifacts. A variable pitch logarithmic spiral trajectory is designed to critically sample the low‐frequency region in k‐space and gradually undersample the high‐frequency region. An approximate analytical expression for the trajectory provides a fast means to calculate the gradient waveforms and the sampled data points. A numerical method is introduced based on the trajectory curvature and the rate of change in the gradient magnitude with time for the composite Archimedean‐logarithmic trajectory. The pulse sequence is implemented and images are acquired on phantoms and human hearts. The images show improved image resolution and some improvement in image quality as a result of increased extent in k‐space and reduction in aliasing artifacts, respectively. Magn Reson Med 46:1130–1135, 2001. © 2001 Wiley‐Liss, Inc.
Lipofuscin accumulation in the vastus lateralis muscle in patients with chronic obstructive pulmonary disease
Authors: Allaire Joakim , Maltais François , LeBlanc Pierre , Simard Pierre‐Michel , Whittom François , Doyon Jean‐François , Simard Clermont , Jobin Jean 
Published: August 2002

AbstractExercise‐induced oxidative stress has been reported in patients with chronic obstructive pulmonary disease (COPD) and may play a role in muscle fatigue. It is speculated that oxidative stress during exercise originates from the contracting muscles but this has not been documented. The accumulation of lipofuscin, a marker of cellular oxidative damage, was evaluated in the vastus lateralis muscle in 17 patients with COPD and 10 healthy subjects of similar age. Each subject performed a stepwise exercise test up to maximal capacity during which oxygen uptake (& pVO2) was measured. Resting and peak exercise blood gases were also obtained. Two indices of lipofuscin accumulation were used: lipofuscin inclusions/fiber ratio (LI/F) and lipofuscin inclusions/fiber cross‐sectional area ratio (LI/CSA). These ratios were also determined for each specific fiber‐type. LI/F (P < 0.01) and LI/CSA (P < 0.01) were greater in COPD compared to healthy subjects. LI/F and LI/CSA for all fiber types were also greater in COPD (P < 0.001). In both groups, LI/F (P < 0.001) and LI/CSA (P < 0.01) were higher in type I than in type II fibers. LI/F and LI/CSA did not correlate significantly with resting PaO2 and SaO2, peak VO2, and ΔPaO2 and ΔSaO2 during exercise (P > 0.05). Increased lipofuscin accumulation, a marker of oxidative damage, was found in the vastus lateralis muscle in patients with COPD compared to healthy subjects. Oxidative damage of muscle tissue may thus be involved in skeletal muscle dysfunction and wasting in COPD. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002 DOI 10.1002/mus.10039
Vibration injury damages arterial endothelial cells
Authors: Curry Brian D. , Bain James L.W. , Yan Ji‐Geng , Zhang Lin Ling , Yamaguchi Mark , Matloub Hani S. , Riley Danny A. 
Published: August 2002

AbstractProlonged exposure to hand‐transmitted vibration can cause debilitating neural and vascular dysfunction in humans. It is unclear whether the pathophysiology involves simultaneous or sequential injury of arteries and nerves. The mechanism of vibration injury was investigated in a rat tail model, containing arteries and nerves structurally similar to those in the human hand. Tails were selectively vibrated for 1 or 9 days with the remainder of the animal at rest. One vibration bout of 4 h/day, 60 HZ, 5 g (49 m/s2) acceleration, injured endothelial cells. Injury was signaled by elevated immunostaining for NFATc3 transcription factor. Electron microscopy revealed that vibration for 9 days produced loss and thinning of endothelial cells, with activated platelets coating the exposed subendothelial tissue. Endothelial cells and arterial smooth muscle cells contained double membrane–limited, swollen processes indicative of vasoconstriction‐induced damage. Laser doppler surface recording demonstrated that 5 min of vibration significantly diminished tissue blood perfusion. These findings indicate that early injury involves vasoconstriction and denuding of the arterial endothelium. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Is the cutaneous silent period an opiate‐sensitive nociceptive reflex?
Authors: Inghilleri Maurizio , Conte Antonella , Frasca Vittorio , Berardelli Alfredo , Manfredi Mario , Cruccu Giorgio 
Published: August 2002

AbstractIn humans, high‐intensity electrical stimuli delivered to the fingers induce an inhibitory effect on C7–T1 motoneurons. This inhibitory reflex, called the cutaneous silent period (CSP) is considered a defense response specific for the human upper limbs. It is not clear whether the CSP—like other defense responses such as the corneal reflex and the R III reflex—is an opiate‐sensitive nociceptive reflex. Because opiates suppress some, but not all, nociceptive reflexes, we studied the effect of the narcotic‐analgesic drug fentanyl on the CSP and the R III reflex. The CSP was recorded from the first dorsal interosseous (FDI) muscle in seven normal subjects during voluntary contraction, before and 10 and 20 min after fentanyl injection. To assess possible fentanyl‐induced changes, we also tested the effect of finger stimulation on motor evoked potentials (MEPs) elicited in the FDI muscle by transcranial magnetic stimulation before and after fentanyl injection. Fentanyl‐induced changes were also studied on the R III reflex recorded from the biceps femoris muscle. Fentanyl, as expected, suppressed the R III reflex but failed to change the inhibitory effect of finger stimulation on FDI motoneurons. Finger stimulation reduced the size of MEPs in the FDI, and fentanyl injection left this inhibitory effect unchanged. The differential fentanyl‐induced modulation of the CSP and R III reflex provides evidence that the CSP circuit is devoid of μ‐opiate receptors and is therefore an opiate‐insensitive nociceptive reflex, which may be useful in the assessment of central‐acting, non‐opioid drugs. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Lower body negative pressure: A test of cardiovascular autonomic function
Authors: Patel Akash R. , Engstrom Jennifer E. , Tusing Lora D. , McNeeley Kevin J. , Chelimsky Thomas C. 
Published: August 2002

AbstractLower body negative pressure (LBNP) may provide an alternative test of cardiovascular autonomic function for patients unable to perform the Valsalva maneuver (VM). LBNP at −40 mmHg for 30 s was compared to the VM at 40 mmHg for 15 s with heart rate and blood pressure measured continuously in three age groups: 10–25 years; 26–40 years; and 41–55 years. Heart rate and blood pressure responses were comparable, with moderately diminished changes in blood pressure and heart rate in the LBNP test. When heart response to LBNP was converted to a ratio similar to that calculated for the VM, a high degree of correlation was found (R2 = 0.5711). The LBNP test shows promise as an alternative test of cardiovascular autonomic function based on studies in normal subjects. The less marked changes may relate to the more passive nature of the applied stress. Future work should improve the device's accessibility and establish values for patients with autonomic disorders. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 481–487, 2001
Molecular mechanisms of neurotransmitter release
Authors: Fon Edward A. , Edwards Robert H. 
Published: August 2002

AbstractThe release of neurotransmitter from neurons represents one of the pivotal events in synaptic transmission. Neurotransmitters are released from synaptic vesicles in presynaptic neurons in response to neural activity, diffuse across the synaptic cleft, and bind specific receptors in order to bring about changes in postsynaptic neurons. Some of the molecular processes that govern neurotransmitter release are now becoming better understood. The steps involved can be broken down into two partially overlapping presynaptic cycles, the neurotransmitter cycle and the synaptic vesicle cycle. The neurotransmitter cycle involves transmitter biosynthesis, storage, reuptake, and degradation. The synaptic vesicle cycle involves targeting to the nerve terminal, docking, fusion, endocytosis, and recycling. Biochemical and structural studies have yielded important insight into our understanding of each of these two cycles. Further, both pharmacological and genetic interference with either of these cycles results in profound alterations in synaptic transmission and behavior, demonstrating the crucial role of neurotransmitter release. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 581–601, 2001
A novel stimulation pattern improves performance during repetitive dynamic contractions
Authors: Kebaetse Maikutlo B. , Lee Samuel C. K. , Binder‐Macleod Stuart A. 
Published: August 2002

AbstractThe purpose of this study was to determine the effect of three different stimulation patterns on repetitive knee movements. Each subject's quadriceps femoris was stimulated with: (1) a constant‐frequency train (CFT) with an interpulse interval (IPI) of 50 ms; (2) a variable‐frequency train (VFT)—similar to the CFT, except with an initial doublet with an IPI of 5 ms; and (3) a doublet‐frequency train (DFT) with multiple doublets (doublet IPI 5 ms) separated by 50 ms, while the muscle was resisted by a load equal to 10% of the muscle's maximum voluntary isometric contraction. The muscle was stimulated while the knee moved through a 50° arc of motion (90° to 40° of flexion). Testing was stopped when the subject failed to reach the target three consecutive times. Results showed that DFTs reached the target (mean ± SD) 36.4 ± 14.4 times, followed by VFTs (25.4 ± 17.9) and CFTs (17.4 ± 11.9). The DFT was the best pattern for producing shortening contractions. The results suggest that DFTs may have significant benefits during clinical functional electrical stimulation. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 744–752, 2001
Nuclear alterations in autosomal‐dominant Emery‐Dreifuss muscular dystrophy
Authors: Sabatelli Patrizia , Lattanzi Giovanna , Ognibene Andrea , Columbaro Marta , Capanni Cristina , Merlini Luciano , Maraldi Nadir M. , Squarzoni Stefano 
Published: August 2002

AbstractElectron microscopy study of muscle biopsies from patients with autosomal‐dominant Emery‐Dreifuss muscular dystrophy revealed nuclear alterations in about 10% of the preserved muscle fibers. The major findings consisted of peripheral heterochromatin loss or detachment from the nuclear envelope, and of interchromatin texture alterations. These abnormalities are similar to those reported in an animal model of the disease and to those found in the X‐linked form of Emery‐Dreifuss muscular dystrophy. These results suggest that an abnormal ultrastructural arrangement of the nuclear periphery is a common feature in the known forms of Emery‐Dreifuss muscular dystrophy, and that several proteins of the nuclear scaffold are necessary in muscle cells to maintain the nuclear structural/functional integrity and a normal muscle cell metabolism. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 826–829, 2001
Variability of frequency and phase between antagonistic muscle pairs in pathological human tremors
Authors: Lauk Michael , Timmer Jens , Guschlbauer Brigitte , Hellwig Bernhard , Lücking Carl‐Herrmann 
Published: August 2002

AbstractWe investigated the electromyographic activity (EMG) of flexor and extensor muscles with different hand positions in patients with essential (ET) and parkinsonian (PD) tremor. Using a previously developed bootstrap method and standard cross‐spectral analysis, we performed statistical tests to assess the effect of hand position on: (1) the frequency of the EMG; and (2) the phase between the EMGs recorded from antagonistic muscle pairs. Frequency as well as phases changed significantly with different positions of the hands but not during the recordings when the position was left unchanged. Besides confirmation that frequency and phase are stationary and reliable parameters during short‐term recordings under controlled laboratory conditions, these results are of particular interest for ambulatory long‐term tremor measurements. A higher variability of the estimated parameters reported in long‐term recordings may perhaps reflect a patient's mobility only. Our study shows that long‐term recording systems should have the means to monitor the patient's movements to provide reliable results. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1365–1370, 2001
Clinical and genetic aspects of distal myopathies
Authors: Saperstein David S. , Amato Anthony A. , Barohn Richard J. 
Published: August 2002

AbstractAlthough most muscle disorders produce proximal weakness, some myopathies may manifest predominantly or exclusively distal weakness. Although several congenital, inflammatory, or metabolic myopathies may produce mainly distal weakness, there are several distinct entities, typically referred to as distal myopathies. Most of these are inherited conditions. The distal myopathies are rare, but characteristic clinical and histological features aid in their identification. Advances in molecular genetics have led to the identification of the gene lesions responsible for several of these entities and have also expanded our understanding of the genetic relationships of distal myopathies to other inherited disorders of muscle. This review summarizes current knowledge of the clinical and molecular aspects of the distal myopathies. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1440–1450, 2001
Effect of recording window and stimulation variables on the statistical technique of motor unit number estimation
Authors: Lomen‐Hoerth Catherine , Olney Richard K. 
Published: August 2002

AbstractA variety of methods are used for the selection of recording window sizes and stimulation current levels for statistical motor unit number estimation (MUNE). This study compares different recording window sizes and stimulation current levels within those windows in the same subjects to determine the effect on MUNE value and reproducibility. Four recording windows of 10% size were compared with four of 5%, with the stimulation current set in the lower quarter, middle half, and upper quarter of the recording window. MUNE for stimulation current set in the lower quarter of the window was 81 (62–103) for 10% recording windows and 120 (108–135) for 5% recording windows, and 91 (61–123) and 133 (120–154) for stimulation current set in the middle half. Increasing the recording window size from 5 to 10% lowers the MUNE value in controls, but tends to improve reproducibility; and setting the stimulation current in the lower quarter of the window, changes the MUNE value minimally, while tending to improve further reproducibility. Excellent reproducibility of MUNE was obtained when applied to a pilot group of 10 amyotrophic lateral sclerosis patients. Based on this study, we conclude that the ideal method for statistical motor unit estimation involves using 10% recording windows and setting the stimulation current in the lower quarter of the recording window. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1659–1664, 2001
Adaptive finite element analysis of mode I fracture in cement‐based materials
Authors: Prasad M. V. K. V. , Krishnamoorthy C. S. 
Published: August 2002

AbstractMicroscopic studies using advanced experimental techniques have provided better insight into the fracture mechanisms in cement‐based materials. A clear understanding of fracture mechanisms is critical for the development of rigorous computational models for analysing fracture. Fracture analysis is usually carried out by finite element method. Accuracy of FE analysis depends upon the choice of mesh and for the predictions to be reliable, discretization errors are to be minimized. In cohesive crack approach, the non‐linearity is limited to the boundary conditions along the geometric discontinuity while the bulk of the material retains its elastic nature. The paper presents a mesh‐adaptive strategy based on ZZ error estimator to model discrete crack propagation in cement‐based materials. Examples of simulations have demonstrated the potential of the mesh‐adaptive technique in modelling the evolution of the localized strain profiles as well as failure of concrete test specimen. Copyright © 2001 John Wiley & Sons, Ltd.
Application of thermodynamics to the global modelling of shallow foundations on frictional material
Authors: Le Pape Y. , Sieffert J.‐G. 
Published: August 2002

AbstractSoil–shallow foundation interaction has been theoretically analysed within the framework of thermomechanics. The design of a global interaction model has been achieved with an original treatment of the Clausius–Duhem inequality. The role of the gravity volume forces is emphasized. The paper is focused on a strip footing based on dense sand and subjected to time‐independent plastic processes. The theoretical approach has confirmed that an associated global flow rule cannot be expected to hold true. The analysis of the sources of dissipation has led to the development of a soil–footing interface model and a complete interaction model accounting for the interface constraints and the intrinsic frictional properties of the soil. Finally, the abilities of the complete model are checked by comparisons with experimental results found in the literature. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of property variation and modelling on convection in a fluid overlying a porous layer
Authors: Straughan B. 
Published: August 2002

AbstractAn accurate computational analysis is presented for the onset of thermal convection in a two‐layer system which is comprised of a saturated layer of porous material described by Darcy's law, over which lies a layer of the same saturating fluid. The two‐layer system is heated from below and the upper (fluid) surface is allowed to be fixed or stress free. The onset of convection may have a bi‐modal nature in which convection may be dominated by the porous medium or by the fluid depending on the depths of the relative layers, but this is strongly controlled by material parameters. The effect of variation of relevant fluid and porous material properties is investigated in detail, as is the effect of the interface boundary condition between the fluid and the porous medium. Copyright © 2001 John Wiley & Sons, Ltd.