bluuebunny/crossref_metadata_2025_split huggingface dataset:
mt1 Receptor‐mediated antiproliferative effects of melatonin on the rat uterine antimesometrial stromal cells
Authors: Zhao Hang , Pang Shiu F. , Poon Angela M.S. 
Published: August 2002

AbstractIt has been shown that melatonin regulates uterine function. Our previous studies have demonstrated the presence of melatonin receptors in the rat uterine endometrium, indicating that melatonin may act directly on the uterus. In the present study, the histological localization of the rat uterine melatonin binding was revealed by autoradiography and the molecular subtyping was studied by in situ hybridization in the stromal cells. The signal transduction process and effects of melatonin on stromal cell proliferation was also investigated. Our autoradiograms showed that 2[125I]iodomelatonin binding sites were localized in the antimesometrial endometrial stroma. In situ hybridization with specific mt1 receptor cDNA probe in the primary culture of antimesometrial stromal cells demonstrated the expression of mt1 receptor mRNAs. Melatonin dose‐dependently inhibited forskolin‐stimulated cAMP accumulation, which was reversed by pertussis toxin. This indicates that the rat uterine melatonin receptors are negatively coupled to adenylate cyclase via pertussis toxin sensitive Gi protein. Melatonin also inhibited the incorporation of [3H]thymidine in the rat uterine antimesometrial stromal cells, showing that melatonin has an anti‐proliferative effect on the uterus. Our results suggest that melatonin may act directly on the mt1 melatonin receptors in the rat uterine antimesometrial stromal cells to inhibit their proliferation. Its action may be mediated through a pertussis toxin‐sensitive adenylate cyclase coupled Gi‐protein. Mol. Reprod. Dev. 61: 192–199, 2002. © 2002 Wiley‐Liss, Inc.
Living with support in the community: Predictors of choice and self‐determination
Authors: Stancliffe Roger J. 
Published: August 2002

AbstractEnsuring that people with intellectual disability experience typical levels of choice and self‐determination has become an essential objective for quality disability services. Three perspectives on self‐determination were identified in the literature: psycho‐educational, ecological, and socio‐political. Personal characteristics, specific self‐determination competencies, and environmental variables all were found to be associated with choice and self‐determination. Living environments that were smaller and more individualized were linked to greater choice and self‐determination. The theoretical perspective investigators applied to the issues influenced approaches to research and intervention, and differences in emphasis were evident regarding the relative importance of self‐determination competencies and environmental factors. MRDD Research Reviews 7:91–98, 2001. © 2001 Wiley‐Liss, Inc.
Renal T perfusion using an iron oxide nanoparticle contrast agent—influence of T1 relaxation on the first‐pass response
Authors: Bjørnerud Atle , Johansson Lars O. , Ahlström Håkan K. 
Published: August 2002

AbstractQuantitative perfusion measurements require accurate knowledge of the correlation between first‐pass signal changes and the corresponding tracer concentration in tissue. In the present study, a detailed analysis of first‐pass renal cortical changes in T1 and T following bolus injection of the iron oxide nanoparticle NC100150 Injection was investigated in a pig model using a double‐echo gradient‐echo sequence. The estimated change in 1/T during first pass calculated from single‐echo sequences was compared to the true double‐echo‐derived 1/T curves. Using a single‐echo (TE = 6 ms) spoiled gradient‐echo sequence, the first‐pass 1/T response following a bolus injection of 1 mg Fe/kg of NC100150 Injection was significantly underestimated due to counteracting T1 effects. Signal response simulations showed that the relative error in the first‐pass response decreased with increasing TE and contrast agent dose. However, both the maximum TE and the maximum dose are limited by excessive cortical signal loss, and the maximum TE is further limited by high temporal resolution requirements. The problem of T1 contamination can effectively be overcome by using a double‐echo gradient‐echo sequence. This yields a first‐pass response that truly reflects the tissue tracer concentration, which is a critical requirement for quantitative renal perfusion assessment. Magn Reson Med 47:298–304, 2002. © 2002 Wiley‐Liss, Inc.
Human rectal adenocarcinoma: Demonstration of 1H‐MR spectra in vivo at 1.5 T
Authors: Dzik‐Jurasz A.S.K. , Murphy P.S. , George M. , Prock T. , Collins D.J. , Swift I. , Leach M.O. , Rowland I.J. 
Published: August 2002

AbstractThis study was designed to determine whether 1H‐MR spectra of locally advanced human rectal adenocarcinoma could be acquired in vivo at 1.5 T. Despite the relatively large size of these neoplasms, only six out of 21 tumors accommodated a voxel size of 8 cm3. This was due to air pockets within the tumor mass, which limited voxel positioning. Localized proton spectra were acquired at short (20 ms) and long (135 ms) echo times (TEs) using a single‐voxel technique. The most commonly detected metabolites were choline and lipid. Magn Reson Med 47:809–811, 2002. © 2002 Wiley‐Liss, Inc.
Imaging the changes in renal T1 induced by the inhalation of pure oxygen: A feasibility study
Authors: Jones Richard A. , Ries Mario , Moonen Chrit T.W. , Grenier Nicolas 
Published: August 2002

AbstractThe effect of the inhalation of pure oxygen on the kidney was evaluated by measuring monoexponential T1 and T relaxation times in nine volunteers using a multiple‐shot turbo spin echo and multiple echo gradient echo sequences, respectively. The T1 of the renal cortex decreased significantly when breathing pure oxygen as compared to normoxia (from 882 ± 59 to 829 ± 70 msec, P < 0.05), while that of the renal medulla was unchanged. No significant changes were seen in the T of either compartment. Dynamic imaging using an inversion recovery sequence with an optimized inversion time typically produced signal changes of 20% in the renal cortex. Studies to assess if oxygen‐induced changes in flow contributed to this effect showed that the flow contribution was not significant. Although longer inversion times (880 ms) produced optimal contrast, acceptable contrast was also obtained at shorter inversion times (450 msec) in the renal cortex, spleen, and lung, with the latter being of opposite polarity to the other two tissues, implying a shorter parenchymal T1 than previously reported in the literature. The results are consistent with oxygen acting as an intravascular contrast agent which induces a shortening of T1 in the arterial blood volume. Magn Reson Med 47:728–735, 2002. © 2002 Wiley‐Liss, Inc.
Analysis of wave behavior in lossy dielectric samples at high field
Authors: Yang Qing X. , Wang Jinghua , Zhang Xiaoliang , Collins Christopher M. , Smith Michael B. , Liu Haiying , Zhu Xiao‐Hong , Vaughan J. Thomas , Ugurbil Kamil , Chen Wei 
Published: August 2002

AbstractRadiofrequency (RF) field wave behavior and associated nonuniform image intensity at high magnetic field strengths are examined experimentally and numerically. The RF field produced by a 10‐cm‐diameter surface coil at 300 MHz is evaluated in a 16‐cm‐diameter spherical phantom with variable salinity, and in the human head. Temporal progression of the RF field indicates that the standing wave and associated dielectric resonance occurring in a pure water phantom near 300 MHz is greatly dampened in the human head due to the strong decay of the electromagnetic wave. The characteristic image intensity distribution in the human head is the result of spatial phase distribution and amplitude modulation by the interference of the RF traveling waves determined by a given sample‐coil configuration. The numerical calculation method is validated with experimental results. The general behavior of the RF field with respect to the average brain electrical properties in a frequency range of 42–350 MHz is also analyzed. Magn Reson Med 47:982–989, 2002. © 2002 Wiley‐Liss, Inc.
Two‐component diffusion tensor MRI of isolated perfused hearts
Authors: Hsu Edward W. , Buckley David L. , Bui Jonathan D. , Blackband Stephen J. , Forder John R. 
Published: August 2002

AbstractNonmonoexponential MR diffusion decay behavior has been observed at high diffusion‐weighting strengths for cell aggregates and tissues, including the myocardium; however, implications for myocardial MR diffusion tensor imaging are largely unknown. In this study, a slow‐exchange‐limit, two‐component diffusion tensor model was fitted to diffusion‐weighted images obtained in isolated, perfused rat hearts. Results indicate that there are at least two distinct components of anisotropic diffusion, characterized by a “fast” component whose principal diffusivity is comparable to that of the perfusate, and a highly anisotropic “slow” component. It is speculated that the two components correspond to tissue compartments and have a general agreement with the orientations of anisotropy, or fiber orientations, in the myocardium. Moreover, consideration of previous studies of myocardial diffusion suggests that the presently observed fast component may likely be dominated by diffusion in the vascular space, whereas the slow component may include the intracellular and interstitial compartments. The implications of the results for myocardial fiber orientation mapping and limitations of the current two‐component model used are also discussed. Magn Reson Med 45:1039–1045, 2001. © 2001 Wiley‐Liss, Inc.
Magnetization preparation during the steady state: Fat‐saturated 3D TrueFISP
Authors: Scheffler Klaus , Heid Oliver , Hennig Jürgen 
Published: August 2002

AbstractA novel fat saturation scheme is proposed which combines spectral fat saturation with a steady‐state 3D true Fast Imaging with Steady Precesson (TrueFISP) sequence. Fat saturation consisted of a conventional frequency‐selective excitation pulse surrounded by spoiler gradients. This saturation block was periodically repeated within a continuously running TrueFISP sequence. Except for the fat signals, the steady‐state signal formation and the resulting image contrast of TrueFISP was not modified by the periodically inserted fat saturation block. This was achieved by a α/2 flip‐back pulse before the fat saturation block, which stores the established steady‐state transverse magnetization as pure longitudinal magnetization. After fat saturation this longitudinal magnetization was excited by a α/2 preparation pulse to continue the TrueFISP acquisition. The resulting images show contrast identical to conventional TrueFISP images, but without the usually very bright fat signals. The short repetition time allows acquisition of a 3D data set of the abdomen within a single breath‐hold. Magn Reson Med 45:1075–1080, 2001. © 2001 Wiley‐Liss, Inc.
Chemical shift imaging with spectrum modeling
Authors: An Li , Xiang Qing‐San 
Published: August 2002

AbstractA new chemical shift imaging technique was developed to efficiently obtain separate images for multiple chemical shift peaks from a set of spin‐echo acquisitions. Information from localized NMR spectroscopy was used to model the chemical shift spectrum as sharp peaks with known resonance frequencies but unknown amplitudes. Based on this model, a set of spin‐echo images with shifted 180° RF pulses were acquired, in which the magnetization vectors of different chemical components were put into different directions. The amplitudes of the chemical shift peaks were obtained by solving nonlinear equations in a region‐growing process. Experimental results on an ethanol phantom as well as a subject with silicone breast implants are presented. Magn Reson Med 46:126–130, 2001. © 2001 Wiley‐Liss, Inc.
Theoretical analysis of the effect of imperfect slice profiles on tagging schemes for pulsed arterial spin labeling MRI
Authors: Keilholz‐George Shella D. , Knight‐Scott Jack , Berr Stuart S. 
Published: August 2002

AbstractPulsed arterial spin labeling (ASL) techniques provide a noninvasive method of obtaining qualitative and quantitative perfusion images with MRI. ASL techniques employ inversion recovery and/or saturation recovery to induce perfusion weighting, and thus the performance of these techniques is dependent on the slice profiles of the inversion or saturation pulses. This article systematically examines through simulations the effects of slice profile imperfections on the perfusion signal for nine labeling schemes, including FAIR, FAIRER, and EST (UNFAIR). Each sequence is evaluated for quantitative accuracy, suppression of stationary signal, and magnitude of perfusion signal. Perfusion effects are modeled from a modified Bloch equation and experimentally determined slice profiles. The results show that FAIR, FAIRER, and EST have excellent tissue suppression. The magnitude of the perfusion signal is comparable for FAIR and FAIRER, with EST providing a slightly weaker signal. For quantitative measurements, all three methods underestimate the perfusion signal by more than 20%. Of the additional six ASL techniques examined, only one performed well in this model. This method, which combines inversion and saturation recovery, yields improved signal accuracy (<15% difference from the theoretical value) and tissue suppression similar to that of FAIR and its variants, but has only half the signal. Magn Reson Med 46:141–148, 2001. © 2001 Wiley‐Liss, Inc.
Bicuculline‐induced brain activation in mice detected by functional magnetic resonance imaging
Authors: Mueggler Thomas , Baumann Diana , Rausch Martin , Rudin Markus 
Published: August 2002

AbstractDynamic measurements of local changes in relative cerebral blood volume (CBVrel) during a pharmacological stimulation paradigm were performed in mice. Using magnetite nanoparticles as an intravascular contrast agent, high‐resolution CBVrel maps were obtained. Intravenous administration of the GABAA antagonist bicuculline prompted increases in local CBVrel as assessed by MRI with a high spatial resolution of 0.2 × 0.2 mm2 and a temporal resolution of 21 s. Signal changes occurred 20–30 s after the onset of drug infusion in the somatosensory and motor cortex, followed by other cortical and subcortical structures. The magnitudes of the CBVrel increases were 18% ± 4%, 46% ± 14%, and 67% ± 7%, as compared to prestimulation values for the cortex, and 9% ± 3%, 25% ± 4%, and 36% ± 7% for the caudate putamen for bicuculline doses of 0.6, 1.25, and 1.5 mg/kg, respectively. On‐line monitoring of transcutaneous carbon dioxide tension PtcCO2 reflecting arterial PaCO2 did not show any alteration during the stimulation paradigm. One of five of the mice receiving the highest bicuculline dose, and three of seven receiving the intermediate dose displayed a different cortical response pattern. After a CBVrel increase of 40% lasting for approximately 1 min, significant CBVrelreductions by 80% have been observed. Subcortical structures did not display this behavior. The present study suggests that this noninvasive approach of functional MRI (fMRI) can be applied to study drug‐induced brain activation by central nervous system (CNS) drugs in mice under normal and pathological situations. Magn Reson Med 46:292–298, 2001. © 2001 Wiley‐Liss, Inc.
Theoretical analysis of the effects of noise on diffusion tensor imaging
Authors: Anderson Adam W. 
Published: August 2002

AbstractA theoretical framework is presented for understanding the effects of noise on estimates of the eigenvalues and eigenvectors of the diffusion tensor at moderate to high signal‐to‐noise ratios. Image noise produces a random perturbation of the diffusion tensor. Power series solutions to the eigenvalue equation are used to evaluate the effects of the perturbation to second order. It is shown that in anisotropic systems the expectation value of the largest eigenvalue is overestimated and the lowest eigenvalue is underestimated. Hence, diffusion anisotropy is overestimated in general. This result is independent of eigenvalue sorting bias. Furthermore, averaging eigenvalues over a region of interest produces greater bias than averaging tensors prior to diagonalization. Finally, eigenvector noise is shown to depend on the eigenvalue contrast and imposes a theoretical limit on the accuracy of simple fiber tracking schemes. The theoretical results are shown to agree with Monte Carlo simulations. Magn Reson Med 46:1174–1188, 2001. © 2001 Wiley‐Liss, Inc.
Detection and prevalence of α‐latrotoxin–like effects of serum from patients with Guillain–Barré syndrome
Authors: Jacobs Bart C. , Bullens Roland W.M. , O'Hanlon Graham M. , Ang C. Wim , Willison Hugh J. , Plomp Jaap J. 
Published: August 2002

AbstractAnti‐GQ1b antibodies are associated with the Miller Fisher syndrome (MFS), a variant of the Guillain–Barré syndrome (GBS). In the ex vivo mouse diaphragm, anti‐GQ1b–positive MFS serum induces muscle fiber twitching, a temporary dramatic increase of spontaneous quantal acetylcholine release, and transmission blockade at neuromuscular junctions (NMJs). These effects resemble those of α‐latrotoxin (α‐LTx) and are induced by antibody‐mediated activation of complement. We developed an assay for detection of the α‐LTx–like effect, using muscle fiber twitching as indicator. We tested 89 serum samples from GBS, MFS, and control subjects, and studied correlations with clinical signs, anti‐ganglioside antibodies, micro‐electrode physiology, and complement deposition at NMJs. Twitching was observed with 76% of the MFS and 10% of the GBS samples. It was associated with ophthalmoplegia and anti‐GQ1b antibodies in patients, and with increased spontaneous acetylcholine release and C3c‐deposition at mouse NMJs. This study strongly suggests that antibodies to GQ1b (with cross‐reactivity to related gangliosides) are responsible for the α‐LTx–like activity. The twitching assay is an efficient test for detection of this effect, and allows for screening of large numbers of samples and modifying drugs. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Muscle strength following direct injection of doxorubicin into rabbit sternocleidomastoid muscle in situ
Authors: Falkenberg Jon H. , Iaizzo Paul A. , McLoon Linda K. 
Published: August 2002

AbstractDirect intramuscular injection of doxorubicin results in permanent myofiber loss. A previous phase I trial demonstrated that such injections could successfully treat blepharospasm and hemifacial spasm. Our previous in vitro study demonstrated that doxorubicin resulted in a dose‐dependent reduction in isometric force generation in sternocleidomastoid muscle in rabbits. This present study examined alterations in force generation in these treated muscles in situ, i.e., with the blood and nerve supply intact. Two months after a single doxorubicin injection, functional changes in peak twitch, tetanic force generation, and fatigue rate were assessed in control and doxorubicin‐treated sternocleidomastoid muscles in rabbits. Peak force measurements were reduced in the treated muscles. These reductions in muscle strength were significantly greater at tetanic peak amplitudes. Fatigue rate was not altered by doxorubicin treatment of the sternocleidomastoid muscles. These findings support the potential clinical use of doxorubicin chemomyectomy for the treatment of patients with cervical dystonia. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Epidermal nerve fiber density in sensory ganglionopathies: Clinical and neurophysiologic correlations
Authors: Lauria Giuseppe , Sghirlanzoni Angelo , Lombardi Raffaella , Pareyson Davide 
Published: August 2002

AbstractWe assessed the involvement of somatic unmyelinated fibers in sensory ganglionopathies by skin biopsy and quantitative sensory testing (QST). Sixteen patients with ganglionopathy, 16 with axonal neuropathy, and 15 normal controls underwent skin biopsy at the proximal thigh and the distal leg. Intraepidermal nerve fibers (IENF) were immunostained by antiprotein gene product 9.5, and their linear density was quantified under light microscopy. Confocal microscopy studies with double staining of nerve fibers and basement membrane were also performed. Healthy subjects and neuropathy patients showed the typical proximodistal gradient of IENF density; in neuropathies, values were significantly lower at the distal site of the leg, confirming the length‐dependent loss of cutaneous innervation. Conversely, ganglionopathy patients with hyperalgesic symptoms did not show any change of IENF density between the proximal thigh and the distal leg. The distinct pattern of epidermal denervation seen in sensory ganglionopathy reflected the degeneration of somatic unmyelinated fibers in a fashion that was not length‐dependent, which was consistent with both clinical and neurophysiologic observations and supported the diagnosis. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1034–1039, 2001
Who did what? Authorship and contribution in 2001
Authors: Rennie Drummond 
Published: August 2002

AbstractNumerous examples of irresponsible authorship are associated with the rise in the number of authors per article and with the documented rise in authorship disputes. Multiple co‐investigators have become the norm, and a result is that old concepts of authorship—which, when there was but one author, automatically linked credit with accountability—have eroded. The answer, in the tradition of scientific transparency, is for authors to decide together their individual contributions and disclose these to their readers. This disclosure is now required by many major general medical journals and has been adopted by the International Committee of Medical Journal Editors as the standard. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1274–1277, 2001
Coupled damage and plasticity modelling in transient dynamic analysis of concrete
Authors: Gatuingt Fabrice , Pijaudier‐Cabot Gilles 
Published: August 2002

AbstractIn a concrete structure subjected to an explosion, for example a concrete slab, the material is subjected to various states of stress which lead to many modes of rupture. Closer to the explosive, a state of strong hydrostatic compression is observed. This state of stress produces an irreversible compaction of the material. Away from the zone of explosion, confinement decreases and the material undergoes compression with a state of stress, which is slightly triaxial. Finally, the compression wave can be reflected on a free surface and becomes a tensile wave, which by interaction with the compression wave, produces scabbing. We present, in this paper, a model aimed at describing these three failure modes. It is based on visco‐plasticity and rate dependent damage in which a homogenization method is used in order to include the variation of the material porosity due to compaction. The model predictions are compared with several experiments performed on the same concrete. Computations of split Hopkinson tests on confined concrete, a tensile test with scabbing, and an explosion on a concrete slab are presented. Copyright © 2001 John Wiley & Sons, Ltd.