bluuebunny/crossref_metadata_2025_split huggingface dataset:
Type II iodothyronine deiodinase is preferentially expressed in rainbow trout (oncorhynchus mykiss) liver and gonads*
Authors: Sambroni Elisabeth , Gutieres Stéphanie , Cauty Chantal , Guiguen Yann , Breton Bernard , Lareyre Jean‐Jacques 
Published: August 2002

AbstractIt is well admitted that thyroid hormones (TH) play a role in the development of vertebrates. The major secretory product of the thyroid is a pro‐hormone, T4, which is activated in peripheral tissues by outer ring deiodination to T3. We have isolated from rainbow trout testis, a full length cDNA encoding type II iodothyronine deiodinase (rtD2). The cDNA was 2410 nucleotides long and coded for a polypeptide of 264 amino acids including a selenocysteine residue. The predicted molecular weight of rtD2 was 29.3 kDa and the isoelectric point 8.71. The deduced amino acids sequence showed 80% identity with Fundulus heteroclitus D2 (fhD2) but only 68–69% identity with rat, mouse, and human D2. The 3′ UTR contained a putative selenocysteine insertion sequence (SECIS) similar to that described in human cDNA. The rtD2 gene was isolated and the gene structure was similar to that described in human with two exons separated by a large intron. We studied rtD2 gene expression by Northern blot analysis using total RNA extracted from testis, ovary, and other tissues. We found a high expression of a 3 kb transcript in liver and in gonads. A lower expression was also detected in posterior kidney. In testis, rtD2 mRNA expression was dependent on spermatogenic stages: it increased at the onset of spermatogenesis. Our results show that the structural characteristics of the D2 protein and gene have been highly conserved during evolution. The rtD2 mRNA expression in the gonads suggests that rtD2 may be a key factor regulating local supply of active T3 during rainbow trout gametogenesis. Mol. Reprod. Dev. 60: 338–350, 2001. © 2001 Wiley‐Liss, Inc.
Independent component analysis applied to diffusion tensor MRI
Authors: Arfanakis Konstantinos , Cordes Dietmar , Haughton Victor M. , Carew John D. , Meyerand M. Elizabeth 
Published: August 2002

AbstractThe accuracy of the outcome in a diffusion tensor imaging (DTI) experiment depends on the acquisition scheme as well as the postprocessing methods used. In the present study, the DTI results acquired after applying different combinations of diffusion‐weighted (DW) gradient orientations were initially compared. Then, spatially independent component analysis (ICA) was applied to the T2 and DW images. In all cases a single component was detected that was similar to the map of the trace of the diffusion tensor, but contained a reduced amount of noise. Furthermore, when no correction for eddy current artifacts was used in the image acquisition scheme, the effects of eddy currents were separated by ICA into independent components. After these components were removed, conventional estimation of the diffusion tensor was performed on the modified data. No artifact was contained in the final rotationally invariant scalar quantities that describe the intrinsic diffusion properties. Additionally, independent components that mapped major white matter fiber tracts in the human brain were identified. Finally, the noise included in the original T2 and DW images was also separated by ICA into independent components. These components were subsequently removed and a reduction of noise in the final DTI results was achieved. Magn Reson Med 47:354–363, 2002. © 2002 Wiley‐Liss, Inc.
Assessment of T1 and T effects in vivo and ex vivo using iron oxide nanoparticles in steady state—dependence on blood volume and water exchange
Authors: Bjørnerud Atle , Johansson Lars O. , Briley‐Sæbø Karen , Ahlström Håkan K. 
Published: August 2002

AbstractAccurate knowledge of the relationship between contrast agent concentration and tissue relaxation is a critical requirement for quantitative assessment of tissue perfusion using contrast‐enhanced MRI. In the present study, using a pig model, the relationship between steady‐state blood concentration levels of an iron oxide nanoparticle with a hydrated diameter of 12 nm (NC100150 Injection) and changes in the transverse and longitudinal relaxation rates (1/T and 1/T1, respectively) in blood, muscle, and renal cortex was investigated at 1.5 T. Ex vivo measurements of 1/T and 1/T1 were additionally performed in whole pig blood spiked with different concentrations of the iron oxide nanoparticle. In renal cortex and muscle, 1/T increased linearly with contrast agent concentration with slopes of 101 ± 22 s−1mM−1 and 6.5 ± 0.9 s−1mM−1 (mean ± SD), respectively. In blood, 1/T increased as a quadratic function of contrast agent concentration, with different quadratic terms in the ex vivo vs. the in vivo experiments. In vivo, 1/T1 in blood increased linearly with contrast agent concentration, with a slope (T1‐relaxivity) of 13.9 ± 0.9 s−1mM−1. The achievable increase in 1/T1 in renal cortex and muscle was limited by the rate of water exchange between the intra‐ and extravascular compartments and the 1/T1‐curves were well described by a two‐compartment water exchange limited relaxation model. Magn Reson Med 47:461–471, 2002. © 2002 Wiley‐Liss, Inc.
Detection and elimination of motion artifacts by regeneration of k‐space
Authors: Bydder M. , Larkman D.J. , Hajnal J.V. 
Published: August 2002

AbstractA method has been developed using techniques from partially parallel imaging (PPI) to detect localized inconsistencies in k‐space that are caused by certain types of motion. The inconsistent data are discarded and consistent data regenerated from the remaining data using PPI techniques. The price is a small decrease in signal‐to‐noise ratio (SNR) and additional postprocessing. An iterative scheme is presented which does not require separately acquired coil sensitivity information for the PPI reconstructions. This method has been found to reduce artifact levels in phantom and in vivo test studies. Magn Reson Med 47:677–686, 2002. © 2002 Wiley‐Liss, Inc.
Test‐retest reproducibility of quantitative CBF measurements using FAIR perfusion MRI and acetazolamide challenge
Authors: Yen Yi‐Fen , Field Aaron S. , Martin Eric M. , Ari Narter , Burdette Jonathan H. , Moody Dixon M. , Takahashi Atsushi M. 
Published: August 2002

AbstractThe reproducibility of quantitative cerebral blood flow (CBF) measurements using MRI with arterial spin labeling and acetazolamide challenge was assessed in 12 normal subjects, each undergoing the identical experimental procedure on two separate days. CBF was measured on a 1.5T scanner using a flow‐sensitive alternating inversion recovery (FAIR) pulse sequence, performed both at baseline and 12 min after intravenous administration of acetazolamide. T1 was measured in conjunction with the FAIR scan in order to calculate quantitative CBF. The CBF maps were segmented to separate gray matter (GM) from white matter (WM) for region‐of‐interest (ROI) analyses. Post‐ acetazolamide CBF values (ml/100 g/min, mean ± SD) of 87.5 ± 12.5 (GM) and 46.1 ± 10.8 (WM) represented percent increases of 37.7% ± 24.4% (GM) and 40.1% ± 24.4% (WM). Day‐to‐day differences in baseline CBF were −1.7 ± 6.9 (GM) and –1.4 ± 4.7 (WM) or, relative to the mean CBF over both days for each subject, −2.5% ± 11.7% (GM) and −3.8% ± 13.6% (WM) Day‐ to‐day differences in absolute post‐ACZ CBF increase were −2.5 ± 6.8 (GM) and 2.7 ± 9.4 (WM) or, relative to the mean CBF increase over both days for each subject, –4.7% ± 13.3% (GM) and 9.1% ± 26.2% (WM). Thus, FAIR‐ based CBF measurements show satisfactory reproducibility from day to day, but with sufficient variation to warrant caution in interpreting longitudinal data. The hemispheric asymmetry of baseline CBF and post‐acetazolamide CBF increases varied within a narrower range and should be sensitive to small changes related to disease or treatment. Magn Reson Med 47:921–928, 2002. © 2002 Wiley‐Liss, Inc.
Neuroimaging at 1.5 T and 3.0 T: Comparison of oxygenation‐sensitive magnetic resonance imaging
Authors: Krüger Gunnar , Kastrup Andreas , Glover Gary H. 
Published: August 2002

AbstractNoise properties, the signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), and signal responses were compared during functional activation of the human brain at 1.5 and 3.0 T. At the higher field spiral gradient‐echo (GRE) brain images revealed an average gain in SNR of 1.7 in fully relaxed and 2.2 in images with a repetition time (TR) of 1.5 sec. The tempered gain at longer TRs reflects the fact that the physiological noise depends on the signal strength and becomes a larger fraction of the total noise at 3.0 T. Activation of the primary motor and visual cortex resulted in a 36% and 44% increase of “activated pixels” at 3.0 T, which reflects a greater sensitivity for the detection of activated gray matter at the higher field. The gain in the CNR exhibited a dependency on the underlying tissue, i.e., an increase of 1.8× in regions of particular high activation‐induced signal changes (presumably venous vessels) and of 2.2× in the average activated areas. These results demonstrate that 3.0 T provides a clear advantage over 1.5 T for neuroimaging of homogeneous brain tissue, although stronger physiological noise contributions, more complicated signal features in the proximity of strong susceptibility gradients, and changes in the intrinsic relaxation times may mediate the enhancement. Magn Reson Med 45:595–604, 2001. © 2001 Wiley‐Liss, Inc.
BISTRO: An outer‐volume suppression method that tolerates RF field inhomogeneity
Authors: Luo Y. , de Graaf R.A. , DelaBarre L. , Tannús A. , Garwood M. 
Published: August 2002

AbstractA technique is described for performing frequency‐selective signal suppression with a high degree of tolerance to RF field inhomogeneity. The method is called B1‐insensitive train to obliterate signal (BISTRO). BISTRO consists of multiple amplitude‐ and frequency‐modulated (FM) pulses interleaved with spoiler gradients. BISTRO was developed for the purpose of accomplishing band‐selective signal removal, as in water suppression and outer‐volume suppression (OVS), in applications requiring the use of an inhomogeneous RF transmitter, such as a surface coil. In the present work, Bloch simulations were used to illustrate the principles and theoretical performance of BISTRO. Its performance for OVS was evaluated experimentally using MRI and spectroscopic imaging of phantoms and in vivo animal and human brain. By using FM pulses featuring offset‐independent adiabaticity, BISTRO permitted high‐quality, broadband suppression with one (or two) discrete borders demarcating the edge(s) of the suppression band. Simulations and experiments demonstrated the ability to operate BISTRO with reasonably attainable peak RF power levels and with average RF energy deposition similar to other multipulse OVS techniques. Magn Reson Med 45:1095–1102, 2001. © 2001 Wiley‐Liss, Inc.
Microstrip RF surface coil design for extremely high‐field MRI and spectroscopy
Authors: Zhang Xiaoliang , Ugurbil Kamil , Chen Wei 
Published: August 2002

AbstractA new type of high‐frequency RF surface coil was developed for in vivo proton or other nuclei NMR applications at 7T. This is a purely distributed‐element and transmission line design. The coil consists of a thin strip conductor (copper or silver) and a ground plane separated by a low‐loss dielectric material with a thickness (H). Due to its specific semi‐open transmission line structure, substantial electromagnetic energy is stored in the dielectric material between the thin conductor and the ground plane, which results in a reduced radiation loss and a reduced perturbation of sample loading to the RF coil compared to conventional surface coils. The coil is characterized by a high Q factor, no RF shielding, small physical coil size, lower cost, and easy fabrication. A brief theoretical description of the microstrip RF coil is given that can be used to guide the coil designs. A set of gradient‐recalled echo images were acquired by using the single‐ and two‐turn microstrip RF surface coils from both phantom and human brain at 7T, which show good penetration and sensitivity. The two‐turn coil design significantly improves the B1 symmetry as predicted by the microstrip theory. The optimum H for microstrip surface coils is approximately 7 mm. This coil geometry yields a B1 penetration similar to that of conventional surface coils. SNR comparison was made between the microstrip coil and conventional surface coils with and without RF shielding. The results reveal that the novel surface coil design based on the microstrip concept makes very high‐field MRI/MRS more convenient and efficient in research and future clinics. Magn Reson Med 46:443–450, 2001. © 2001 Wiley‐Liss, Inc.
3D magnetization‐prepared true‐FISP: A new technique for imaging coronary arteries
Authors: Deshpande Vibhas S. , Shea Steven M. , Laub Gerhard , Simonetti Orlando P. , Finn J. Paul , Li Debiao 
Published: August 2002

AbstractThe purpose of this work was to develop an ECG‐triggered, segmented 3D true‐FISP (fast imaging with steady‐state precession) technique to improve the signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) of breath‐hold coronary artery imaging. The major task was to optimize an appropriate magnetization preparation scheme to permit saturation of the epicardial fat signal. An α/2 preparation pulse was used to speed up the approach to steady‐state following a frequency‐selective fat‐saturation pulse in each heartbeat. The application of dummy cycles was found to reduce the oscillation of the magnetization during data acquisition. The fat saturation and magnetization preparation scheme was validated with simulations and phantom studies. Volunteer studies demonstrated substantially increased SNR (55%) and CNR (178%) for coronary arteries compared to FLASH (fast low‐angle shot) with the same imaging time. In conclusion, true‐FISP is a promising technique for coronary artery imaging. Magn Reson Med 46:494–502, 2001. © 2001 Wiley‐Liss, Inc.
Improved analysis of 1H‐MR spectra in the presence of mobile lipids
Authors: Auer Dorothee P. , Gössl Christoff , Schirmer Timo , Czisch Michael 
Published: August 2002

AbstractFocal brain lesions can be associated with proton magnetic resonance spectra (1H‐MRS)‐detectable mobile lipids, reflecting severe tissue degradation and necrosis. However, advanced fitting procedures, such as the LCModel, fail to adequately fit spectra in the presence of lipid resonances. To overcome this, different approaches to generate lipid model spectra were compared using a phantom, real in vivo data, and simulated data. Twenty‐six in vivo short‐echo time (TE) 1H‐MRS from
21 malignant gliomas, four infections, and one ischemia were analyzed to evaluate the performance of the modified LCModel fit. Adding simulated aliphatic resonances at 1.3 and 0.9 ppm improved the overall fitting quality remarkably and allowed good separation of lactate and alanine. Also, a better differentiation of glioblastomas and anaplastic gliomas was achieved. In conclusion, we propose a simple way to efficiently include lipid resonances in the LCModel, allowing a better fit of in vivo short‐TE 1H‐MRS, and demonstrate the diagnostic potential of quantitative assessment of mobile lipids in brain tumors. Magn Reson Med 46:615–618, 2001. © 2001 Wiley‐Liss, Inc.
Novel liver macromolecular MR contrast agent with a polypropylenimine diaminobutyl dendrimer core: Comparison to the vascular MR contrast agent with the polyamidoamine dendrimer core
Authors: Kobayashi Hisataka , Kawamoto Satomi , Saga Tsuneo , Sato Noriko , Hiraga Akira , Ishimori Takayoshi , Akita Yukio , Mamede Marcelo H. , Konishi Junji , Togashi Kaori , Brechbiel Martin W. 
Published: August 2002

AbstractAs MRI contrast agents, more hydrophobic molecules reportedly accumulate in the liver and thus are potentially useful as liver MRI contrast agents. In this study, a generation‐4 polypropylenimine diaminobutane dendrimer (DAB‐Am64), which is expected to be more hydrophobic than the generation‐4 polyamidoamine dendrimer (PAMAM‐G4D), was used to synthesize a conjugate with 2‐(p‐isothiocyanatobenzyl)‐6‐methyl‐diethylenetriaminepentaacetic acid (1B4M) [DAB‐Am64‐(1B4M‐Gd)64] for complexing Gd(III) ions. This DAB conjugate quickly accumulated in the liver and its characteristics were studied and compared with those of a PAMAM conjugate [PAMAM‐G4D‐(1B4M‐Gd)64], which is known to be a useful vascular MRI contrast agent, in regard to its availability as a liver MRI contrast agent. DAB‐Am64‐(1B4M‐Gd)64 accumulated significantly more in the liver and less in blood than PAMAM‐G4D‐(1B4M‐Gd)64 (P < 0.001). Contrast‐enhanced MRI with DAB‐Am64‐(1B4M‐Gd)64 was able to homogeneously enhance liver parenchyma and visualize both portal and hepatic veins of 0.5 mm diameter in mice. In conclusion, DAB‐Am64‐(1B4M‐Gd)64 is a good candidate for a liver MRI contrast agent. Magn Reson Med 46:795–802, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of quantitative T2 mapping and diffusion‐weighted imaging in the normal and pathologic prostate
Authors: Gibbs Peter , Tozer Daniel J. , Liney Gary P. , Turnbull Lindsay W. 
Published: August 2002

AbstractIn this study, diffusion‐weighted images of the human prostate were successfully obtained, enabling quantification of apparent diffusion coefficients (ADCs) in normal and pathologic regions. A dual acquisition fast spin‐echo sequence was used for accurate T2 calculation. T2 values were significantly higher in the peripheral zone than the central gland (P = 0.015). No significant correlations were found in either normal or pathologic tissue between ADC values and relaxation rates for all three gradient directions and the orientationally averaged water diffusion coefficient. Evidence suggesting that diffusional anisotropy is present in normal prostatic tissue is also detailed, with significant differences noted between the z‐component and both the x‐ and y‐components of the ADC for peripheral zone (P < 0.040) and central gland (P < 0.001). Magn Reson Med 46:1054–1058, 2001. © 2001 Wiley‐Liss, Inc.
Disease progression in amyotrophic lateral sclerosis: Predictors of survival
Authors: Magnus T. , Beck M. , Giess R. , Puls I. , Naumann M. , Toyka K.V. 
Published: August 2002

AbstractPredicting the rate of disease progression has become important as trials of new medical treatments for amyotrophic lateral sclerosis (ALS) are planned. Bulbar onset, early impairment of forced vital capacity, and older age have all been associated with shorter survival. We performed a retrospective study to compare survival factors with disease progression in a German ALS population. We analyzed disease progression in 155 patients at intervals of 4 months over a period of 3 years. To evaluate disease progression, the ALS functional rating scale (ALS‐FRS), forced vital capacity (FVC%), and a Medical Research Council (MRC) compound score based on a nine‐step modified MRC scale were used. We compared age (<55 years vs. ≥55 years), different sites of disease onset (bulbar vs. limb), and gender to the rate of disease progression and performed survival analyses. No overall significant difference could be detected when analyzing these subgroups with regard to disease progression. By contrast, significantly longer survival was observed in the younger age group (56 months vs. 38 months, P < 0.0001) and in patients with limb‐onset disease (51 months vs. 37 months, P = 0.0002). Using Cox analyses values we found that the declines of ALS‐FRS, FVC%, and MRC compound score were predictive of survival (P < 0.0001, P = 0.002, and P = 0.003, respectively). Future studies are needed to clarify whether nonspecific factors including muscle atrophy, dysphagia, and coexisting diseases influence prediction of survival in ALS patients. A more precise set of predictors may help to better stratify patient subgroups for future treatment trials. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25:000–000, 2002
Laser evoked potentials using the Nd:YAG laser
Authors: Lefaucheur Jean‐Pascal , Debray Sylvain , Jarry Gilbert 
Published: August 2002

AbstractPain‐related cortical potentials were evoked by skin stimulation of the face and the limbs with 5‐ns–duration laser pulses delivered by a Q‐switched Nd:YAG laser. Such laser pulses, in the nanosecond range, were able to induce pinprick pain sensations and to evoke reproducible laser evoked potentials (LEPs) without visible skin lesions for an energy density of less than 18 mJ/mm2. Low energy densities, around 10 mJ/mm2, were sufficient to reach the pain threshold and to induce LEP. The mean conduction velocity of the stimulated afferent fibers was close to 20 m/s, consistent with the stimulation of Aδ fibers. The amplitude of LEP correlated with pain perception rather than with energy density. The differences, such as wavelength and stimulus duration, between the Q‐switched Nd:YAG laser we used and the lasers that are currently used in LEP studies (i.e., CO2, argon, or Tm:YAG lasers in the millisecond range) are discussed. Our study opens novel perspectives in the LEP field of research by using a new type of laser with a very short pulse duration. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24:496–501, 2001
Impairment of voluntary control of finger motion following stroke: Role of inappropriate muscle coactivation
Authors: Kamper D.G. , Rymer W.Z. 
Published: August 2002

AbstractSubjects with chronic hemiplegia following stroke attempted to perform voluntary isometric, isokinetic, and free contractions of the extensor muscles of the metacarpophalangeal (MCP) joints. We recorded torque, metacarpophalangeal joint angle and velocity, and electromyographic (EMG) activity of the extrinsic extensors and flexors and the first dorsal interosseous (FDI). We found that voluntary MCP joint extension in hemiparetic subjects was greatly impaired in comparison with control subjects: only two of the 11 stroke subjects were able to generate even 0.21 N‐m of isometric extension torque, only two could produce positive finger extension with no load, and none could develop an isokinetic concentric extension. Deficits seemed to result from a combination of coactivation of the finger flexor and extensor muscles and decreased voluntary excitation of the extensors, as normalized flexor and FDI EMG activity were greater for stroke than for control subjects (P < 0.001), but normalized extensor activity was reduced (P < 0.001). © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 673–681, 2001
Prosaposin is immunolocalized to muscle and prosaptides promote myoblast fusion and attenuate loss of muscle mass after nerve injury
Authors: Rende Mario , Brizi Emanuela , Donato Rosario , Provenzano Carlo , Bruno Rosalinda , Mizisin Andrew P. , Garrett Robert S. , Calcutt Nigel A. , Campana W. Marie , O'Brien John S. 
Published: August 2002

AbstractProsaposin is the precursor of the saposins and has both neurotrophic and myelinotrophic activity in vitro and in vivo. Using an antibody specific for the holoprotein, an immunocytochemical survey demonstrated intense staining of adult rat skeletal, cardiac, and smooth muscle cells. Prosaposin immunoreactivity in muscle appears dependent on innervation, as denervated adult rat skeletal muscles showed decreased immunostaining that returned to normal levels after reinnervation. TX14(A), a peptide derived from the neurotrophic sequence of prosaposin, attenuated the decline in muscle mass loss following nerve injury induced by a constricting ligature. In vitro, both L6 myoblasts and primary chick‐embryo myoblasts showed similar prosaposin immunopositivity, mainly in myotubes. TX14(A) induced a threefold increase in L6 myoblast fusion during early stages of differentiation without affecting cell proliferation. The fusion process was decreased in vitro in a dose‐dependent fashion by addition of a neutralizing anti‐prosaposin antibody. These data suggest that, in addition to neurotrophic and myelinotrophic activities, prosaposin has myotrophic properties. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 799–808, 2001