bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orbital growth retardation in retinoblastoma survivors: Work in progress
Authors: Peylan‐Ramu Nili , Bin‐Nun Alona , Skleir‐Levy Miri , Bibas Arie , Koplewitz Benjamin , Anteby Irene , Pe'er Jacob 
Published: August 2002

AbstractBackgroundOrbital growth retardation, after enucleation and/or external beam radiation for retinoblastoma (RB), is a serious late effect. We measured orbital volumes of RB survivors treated at Hadassah University Hospital, Jerusalem, between 1980–1998.ProcedureForty‐five orbits of 28 children with RB (17 bilateral, 11 unilateral) were examined. Thirty‐six orbits were irradiated, 19 enucleated, and 10 both enucleated and irradiated. The orbital volumes were calculated from a three‐dimensional orbital CT reconstruction. The orbits of RB survivors were compared to age‐matched controls.ResultsThe mean age at diagnosis was 13 months, mean follow‐up time was 56 months. The mean volume of RB orbits (14.4 cc) was statistically significantly smaller than control orbits (17.8 cc). There was no difference between the mean volume of orbits treated with enucleation, irradiation or both. The orbital volume of children treated before the age of 12 months was statistically significantly smaller than those treated later. There was no difference between mean volume of fellow orbits in unilateral RB and controls. The mean orbital asymmetry index in control children (2.6%) was statistically significantly smaller than in RB survivors (14%).ConclusionsThere was a significant orbital growth retardation after enucleation and/or irradiation for RB. There was no difference between mean orbital volumes after enucleation, radiation or both. Orbital growth retardation was most prominent in children treated in the first year of life. Although small in number, our study suggests that deferring enucleation and/or irradiation until after the age of 12 months may reduce long‐term complications. Med Pediatr Oncol 2001;37:465–470. © 2001 Wiley‐Liss, Inc.
Muonium atom addition to pyridine and to the pyridinium cation
Authors: Rhodes Christopher J. , Morris Harry , Reid Ivan D. 
Published: August 2002

AbstractMuonium atoms are found to add mainly to the N‐atom and to the ortho and meta positions in pyridine in almost equal amounts, giving pyridinyl and 2‐azacyclohexadienyl radicals and 3‐azacyclohexadienyl radicals, respectively (no addition was observed at the para site); on protonation, as in a sample of PyH+ BF4−, the reactivity follows the positive charge density, being enhanced for addition to the N(H+) position, reduced for the ortho/meta positions, and now conferring a significant yield of the para isomer. These results for genuine reactions of hydrogen atoms are discussed in view of studies of radical formation in these materials, made using EPR spectroscopy, when they are exposed to γ‐rays in cryogenic matrices, for which mechanisms involving charge‐neutralization of initial radical ions are proposed. Copyright © 2001 John Wiley & Sons, Ltd.
High sensitivity of the fluorine NMR signals of difluorovinyl analogs of natural hemin: reconstituted heme proteins and self‐exchange electron transfer in model compounds
Authors: Poliart Christine , Briand Jean‐Francois , Tortevoie Frédérique , Leroy Jacques , Simonneaux Gérard , Bondon Arnaud 
Published: August 2002

AbstractThe chemical shifts of fluorine in difluorovinyl deuteroporphyrin iron complexes were shown to be very sensitive to the spin state of the metal and the nature of the ligand(s). Reconstituted myoglobin was used as a model heme protein with an exchangeable heme. Large variations in the fluorine chemical shifts in both the ferric and ferrous states were observed. This strong sensitivity to the nature of the metal ligand and the structural resemblance to natural hemin make this fluorinated porphyrin a good probe for the study of heme proteins. The large variations of chemical shifts depending on the oxidation state also permitted the measurement of the electron self‐exchange rate constants of bis(1‐methylimidazole)iron complexes in various solvents by analysis of line broadening of the 19F NMR signals. The experimental rate constants were strongly affected by the nature of the solvent, varying from 3.9 × 107 to 24.1 × 108 mol l−1 s−1 for DMSO‐d6 and acetone‐d6, respectively. The solvent parameters were used to estimate the outer‐sphere reorganization energies. The experimental rate constants in chloroform and in DMSO are in good agreement with these calculated outer‐sphere reorganization energies. Copyright © 2001 John Wiley & Sons, Ltd.
Dependence of the long‐range phosphorus–hydrogen coupling constant nJP–H (n = 3,6,7) on the bond order between phosphorus and its substituents: preparation and spectroscopic characterization of several phosphoramidates
Authors: Gholivand Khodayar , Ghadimi Said , Naderimanesh Hossein , Forouzanfar Akbar 
Published: August 2002

AbstractThe examination of spectra of a selected series of phosphoramidates showed that, in addition to a double bond, whenever there are one or two partial multiple bonds in the molecule the long‐range coupling constant, such as 6JP–H, 7JP–H and 3JP–H, either disappears or at least reduces. In particular, the experimental data indicate the unexpected effect of a partial multiple bond between phosphorus and fluorine in 7JP–H and 3JP–H. The preparation of the compounds p‐CH3C6H4NHP(O)Cl2 (II), p‐CH3C6H4NHP(O)(Cl)OC6H4CH3‐p (XIV), m‐CH3C6H4NHP(O)(Cl)OC6H4CH3‐p (XV), m‐CH3C6H4NHP(O)(Cl)OC6H4CH3‐m (XVI) and the rigid molecule CH3C6H3(NH)2P(O)Cl (XVII) are described and they are characterized by 1H, 13C, 31P NMR, IR spectroscopy and elemental analysis. Copyright © 2001 John Wiley & Sons, Ltd.
Transgenic pigs expressing human decay‐accelerating factor regulated by porcine MCP gene promoter
Authors: Murakami Hiroshi , Nagashima Hiroshi , Takahagi Yoichi , Miyagawa Shuji , Fujimura Tatsuya , Toyomura Koji , Nakai Rie , Yamada Mako , Kurihara Takashi , Shigehisa Tamotsu , Okabe Masaru , Seya Tsukasa , Shirakura Ryota , Kinoshita Taroh 
Published: August 2002

AbstractPorcine membrane cofactor protein (pMCP) is abundantly expressed throughout the body with particularly strong expression on the vascular endothelia. Previous studies demonstrated that the promoter of the pMCP gene induced efficient expression of a human complement regulatory protein, decay‐accelerating factor (DAF; CD55), in transgenic mice. In the present study, we tried to produce transgenic pigs with two hybrid genes, 0.9/hDAF and 5.4/hDAF, which were composed of human DAF (hDAF) gene regulated under pMCP promoters of different lengths (0.9 and 5.4 kb). Five live founder transgenic pigs were obtained only with the 0.9/hDAF construct. Although, four founder pigs transmitted the transgene to the second generation, the transmission rates varied among founders. We examined the expression of hDAF in tissues of descendants of two lines (Dm1 and Dm4). Human DAF specific RNAs were confirmed by an RT‐PCR analysis in all organs examined. Levels of hDAF protein in the organs from the descendants of Dm1 line were higher than those in the corresponding human organs as determined by enzyme‐linked immunosorbent assay. Immunohistochemical studies showed that the tissue distribution of hDAF in the descendants of both lines was similar to that of endogenous pMCP. The expression level of hDAF on the vascular endothelial cells in Dm1 line was twice that on the corresponding human cells. We tested whether proinflammatory cytokines upregulate an efficiency of pMCP promoter on hDAF expression in transgenic pigs. Although the expression of hDAF on the human endothelial cells increased with a combination of cytokines, tumor necrosis factor α and interferon‐γ, no cytokine‐induced upregulation was seen in the cells of transgenic pigs. The endothelial cells from transgenic pigs exhibited high resistance to the human serum‐mediated cytolysis. Mol. Reprod. Dev. 61: 302–311, 2002. © 2002 Wiley‐Liss, Inc.
Roles of cAMP in regulation of both MAP kinase and p34cdc2 kinase activity during meiotic progression, especially beyond the MI stage
Authors: Shimada Masayuki , Terada Takato 
Published: August 2002

AbstractTime‐dependent changes in the level of adenosine cyclic AMP (cAMP) in porcine oocytes during meiotic progression from the germinal vesicle stage (GV stage) to the metaphase II stage (MII stage) were examined using reversed‐phase HPLC with UV detection. The concentration of cAMP in oocytes reached a peak at 8 hr of cultivation of cumulus–oocyte complexes (COCs), but it was dramatically decreased after 12‐hr cultivation. After a 28‐hr cultivation period, the level of cAMP in the oocytes had significantly reduced further, and the basal level of cAMP was observed in oocytes cultured at 32 hr and for up to 48 hr. When phosphatidylinositol 3‐kinase (PI 3‐kinase) or protein kinase C (PKC) in cumulus cells [which were required for meiotic progression to the MII stage in porcine oocytes (Shimada and Terada, 2001: Biol Reprod 64:1106–1114)] was suppressed by each specific inhibitor following initial 24‐hr cultivation of COCs, cAMP level in the oocytes was significantly increased. After 24‐hr cultivation in the maturation medium, COCs, which were cultured for an additional 24 hr in the presence of either forskolin or 3‐isobutyl‐1‐methylxanthine (IBMX), exhibited a significant increase in the oocyte cAMP level to the similar level of that in oocytes cultured with PI 3‐kinase inhibitor or PKC inhibitor, and the addition of each agent significantly suppressed meiotic progression from the MI to the MII stage and the activity of mitogen‐activated protein kinase (MAPK) and p34cdc2 kinase. These results demonstrated that when transported into oocytes from the cumulus cells via gap junctions, cAMP plays an important role not only in meiotic resumption, but also in the regulation of meiotic progression beyond the MI stage in porcine oocytes. Mol. Reprod. Dev. 62: 124‐131, 2002. © 2002 Wiley‐Liss, Inc.
Parthenogenetic activation and subsequent development of rat oocytes in vitro
Authors: Jiang Jin‐Yi , Mizuno Satoshi , Mizutani Eiji , Sasada Hiroshi , Sato Eimei 
Published: August 2002

AbstractStudies were undertaken to determine whether electrical stimulation, or ethanol treatment alone or in combination with 6‐dimethylaminopurine (6‐DMAP) influenced the rate of parthenogenetic activation of rat oocytes. The percentages of activated oocytes with pronuclei (89–91%) and those developed to the two‐cell stage (68–72%) were significantly higher after electrical stimulation with direct current (DC) at 100 V/mm, 99 μsec once or twice, than when other DC voltages (75, 150, and 200) were applied or when ethanol or 6‐DMAP treatment was given alone. However, none of the activated oocytes developed beyond the four‐cell stage. The percentages of activated oocytes with pronuclei (100%) that developed to the two‐cell (100%), eight‐cell (89%) and blastocyst stages (50%) were significantly higher when electrical stimulation was followed by treatment with 2 mM 6‐DMAP for 4 hr than when other combined procedures were applied. In conclusion, the results of the present study clearly showed that combined treatment of electrical stimulation or ethanol with 6‐DMAP induces parthenogenetic activation and subsequent development of rat oocytes in vitro. Mol. Reprod. Dev. 61: 120–125, 2002. © 2002 Wiley‐Liss, Inc.
In vitro formation of tetraploid rat blastocysts after fusion of two‐cell embryos
Authors: Krivokharchenko Alexander , Galat Vassili , Ganten Detlev , Bader Michael 
Published: August 2002

AbstractGene targeting technology is not available in the rat which is an animal model of major importance, e.g., in cardiovascular research. This is due to the fact that the rat embryonic stem cell (ESC)‐like cells established by several groups do not form germ‐line chimeras when injected into blastocysts. In the mouse, the aggregation of ESC with tetraploid embryos has allowed the generation of animals completely derived from these cells. However, aggregation of rat ESC‐like cells with tetraploid rat embryos has not yet been attempted to evaluate their developmental capacity. Therefore, we established a method to produce tetraploid rat embryos by fusion at the two‐cell stage. Chemical fusion by polyethylene glycol (PEG) was shown to be less efficient (56.3% fused embryos) than electrofusion (96.1% fused embryos). The rate of development of fused embryos to blastocysts was independent of the fusion method and similar to the rate of control embryos. However, this rate was lower when the embryos had been cultured from the zygote state before fusion (14–20%) compared to freshly isolated two‐cell embryos (41–63%). Alike for the mouse, blastocysts derived from fused two‐cell rat embryos contained about half the number of cells as control blastocysts and were homogeneously tetraploid with no evidence of mosaicism. This method may be useful for the establishment of gene‐targeting technology in the rat. Mol. Reprod. Dev. 61:460–465, 2002. © 2002 Wiley‐Liss, Inc.
Paramagnetic Lanthanide(III) complexes as pH‐sensitive chemical exchange saturation transfer (CEST) contrast agents for MRI applications
Authors: Aime Silvio , Barge Alessandro , Delli Castelli Daniela , Fedeli Franco , Mortillaro Armando , Nielsen Flemming U. , Terreno Enzo 
Published: August 2002

AbstractThe recently introduced new class of contrast agents (CAs) based on chemical exchange saturation transfer (CEST) may have a huge potential for the development of novel applications in the field of MRI. In this work we explored the CEST properties of a series of Lanthanide(III) complexes (Ln = Eu, Dy, Ho, Er, Tm, Yb) with the macrocyclic DOTAM‐Gly ligand, which is the tetraglycineamide derivative of DOTA (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid). These complexes possess two pools of exchangeable protons represented by the coordinated water and the amide protons. Yb‐DOTAM‐Gly displays the most interesting CEST properties when its amide N‐H resonance (16 ppm upfield H2O signal) is irradiated. Up to 70% suppression of the water signal is obtained at pH 8. As the exchange rate of amide protons is base‐catalyzed, Yb‐DOTAM‐Gly results to be an efficient pH‐responsive probe in the 5.5–8.1 pH range. Moreover, a ratiometric method has been set up in order to remove the dependence of the observed pH responsiveness from the absolute concentration of the paramagnetic agent. In fact, the use of a mixture of Eu‐DOTAM‐Gly and Yb‐DOTAM‐Gly, whose exchangeable proton pools are represented by the coordinated water (ca. 40 ppm downfield H2O signal at 312K) and amide protons, respectively, produces a pH‐dependent CEST effect which is the function of the concentration ratio of the two complexes. Magn Reson Med 47:639–648, 2002. © 2002 Wiley‐Liss, Inc.
High‐resolution fMRI using multislice partial k‐space GR‐EPI with cubic voxels
Authors: Hyde James S. , Biswal Bharat B. , Jesmanowicz Andrzej 
Published: August 2002

AbstractThe premises of this work are: 1) the limit of spatial resolution in fMRI is determined by anatomy of the microcirculation; 2) because of cortical gray matter tortuosity, fMRI experiments should (in principle) be carried out using cubic voxels; and 3) the noise in fMRI experiments is dominated by low‐frequency BOLD fluctuations that are a consequence of spontaneous neuronal events and are pixel‐wise dependent. A new model is proposed for fMRI contrast which predicts that the contrast‐to‐noise ratio (CNR) tends to be independent of voxel dimensions (in the absence of partial voluming of activated tissue), TE, and scanner bandwidth. These predictions have been tested at 3 T, and results support the model. Scatter plots of fMRI signal intensities and low‐frequency fluctuations for activated pixels in a finger‐tapping paradigm demonstrated a linear relationship between signal and noise that was independent of TE. The R2 value was about 0.9 across eight subjects studied. The CNR tended to be constant across pixels within a subject but varied across subjects: CNR = 3.2 ± 1.0. fMRI statistics at 20‐ and 40‐ms TE values were indistinguishable, and TE values as short as 10 ms were used successfully. Robust fMRI data were obtained across all subjects using 1 × 1 × 1 mm3 cubic voxels with 10 contiguous slices, although 1.5 × 1.5 × 1.5 mm3 was found to be optimum. Magn Reson Med 46:114–125, 2001. © 2001 Wiley‐Liss, Inc.
Techniques for fast stereoscopic MRI
Authors: Guttman Michael A. , McVeigh Elliot R. 
Published: August 2002

AbstractStereoscopic MRI can impart 3D perception with only two image acquisitions. This economy over standard multiplanar 3D volume renderings allows faster frame rates, which are needed for real‐time imaging applications. Real‐time 3D perception may enhance the appreciation of complex anatomical structures, and may improve hand‐eye coordination while manipulating a medical device during an image‐guided interventional procedure. To this goal, a system is being developed to acquire and display stereoscopic MR images in real‐time. A clinically used, fast gradient‐recalled echo‐train sequence has been modified to produce stereo image pairs. Features have been added for depth cueing, view sharing, and bulk signal suppression. A workstation was attached to a clinical MR scanner for fast data extraction, image reconstruction and stereoscopic image display. Magn Reson Med 46:317–323, 2001. Published 2001 Wiley‐Liss, Inc.
Osmotic effects on the T2 relaxation decay of in vivo muscle
Authors: Gambarota Giulio , Cairns Brian E. , Berde Charles B. , Mulkern Robert V. 
Published: August 2002

AbstractSaline solutions are commonly employed as a vehicle for drugs administered intramuscularly. In this study, in vivo measurements of spin‐spin relaxation (T2) processes by magnetic resonance imaging (MRI) were performed to investigate the distribution of water in rat masseter muscle tissue after intramuscular injection of saline solutions of varying tonicity. Prior to saline injection, image‐based T2 relaxation decay of muscle was monoexponential. After injection of saline, the T2 relaxation decay became multiexponential. Non‐negative least squares (NNLS) analysis of the decay curves revealed two relaxation components: a fast component (T2 = 20–40 ms) and a slow component (T2 = 150–400 ms), which are assigned to intra‐ and extracellular water protons, respectively. Injection of hypertonic saline solutions significantly increased the extracellular water component in muscle tissue compared to isotonic saline solutions, an effect which lasted for more than 60 min. These findings suggest that MRI techniques may be useful to investigate the effect of hyper‐ or hypotonic solutions on muscle tissue in vivo. Magn Reson Med 46:592–599, 2001. © 2001 Wiley‐Liss, Inc.
Extravascular contribution of blood oxygenation level‐dependent signal changes: A numerical analysis based on a vascular network model
Authors: Fujita Norihiko 
Published: August 2002

AbstractIn this study, the extravascular (EV) contribution to blood oxygenation level‐dependent (BOLD) signal changes was evaluated, based on a numerical analysis of the nondimensional Bloch‐Torrey equation for a vascular network model of randomly oriented paramagnetic vessels. From a statistical point of view, the susceptibility‐induced EV BOLD signal changes for both gradient‐ and spin‐echoes are shown to be proportional to cerebral blood volume (CBV). These changes can be expressed by a function of two nondimensional parameters: one represents the characteristic phase change of the signal induced by the deoxyhemoglobin‐containing vessels, and the other represents a diffusion effect relative to the vessel radius. The numerical results showed excellent agreement with the analytical solutions obtained previously for the regimes of small and large diffusion effects. Based on the numerical results for gradient‐ and spin‐echoes, it is possible to show the dependence of the EV BOLD contribution on the echo time, the static magnetic field strength, and the stimulation‐induced CBV change. This dependence can be demonstrated for vessels of small, intermediate, and large radii, which correspond respectively to the slow, intermediate, and fast diffusion regimes. A more realistic functional MRI (fMRI) simulation which includes an intravascular (IV) contribution is presented, with emphasis on the field strength dependence of the BOLD signal changes. Magn Reson Med 46:723–734, 2001. © 2001 Wiley‐Liss, Inc.
In vivo magnetic resonance microscopy of rat spinal cord at 7 T using implantable RF coils
Authors: Bilgen Mehmet , Elshafiey Ibrahim , Narayana Ponnada A. 
Published: August 2002

AbstractAn inductively coupled implanted coil was designed for high‐resolution magnetic resonance (MR) studies of rat spinal cord (SC) in vivo at 7 T. The practical issues involved in implementation of the coil at high fields are discussed, and the adjustment of various parameters for optimizing coil performance are described. The utility of the coil was demonstrated with anatomical, magnetization transfer, diffusion tensor imaging, and proton MR spectroscopy (MRS). Magn Reson Med 46:1250–1253, 2001. © 2001 Wiley‐Liss, Inc.
Topodiagnostic value of blink reflex R1 changes: A digital postprocessing MRI correlation study
Authors: Marx Juergen J. , Thoemke Frank , Fitzek Sabine , Vucurevic Goran , Fitzek Clemens , Mika‐Gruettner Annette , Urban Peter P. , Stoeter Peter , Hopf Hanns C. 
Published: August 2002

AbstractThe aim of the study was to investigate the relation of the blink reflex R1 arc to known anatomical brainstem structures. Acute vascular brainstem lesions as identified by magnetic resonance imaging (MRI) of patients with isolated R1 pathology were superimposed into a stereotactic anatomical atlas using a new method of digital postprocessing. Isolated acute brainstem lesions were documented by diffusion‐weighted MRI in 12 of 24 patients with unilateral R1 pathology. The lesions were located in the ipsilateral mid‐ to lower pons. In three patients only, the lesion had partial contact with the principal sensory nucleus of the trigeminal nerve (PSN) on at least one level. In two patients, the lesion involved the medial longitudinal fasciculus. Most lesions were located medially and ventrally to the PSN on transverse slices. Our results underline the high localizing value of changes in the R1 component of the blink reflex in patients with ipsilateral pontine functional deficits. Although available physiological evidence suggests that the R1 component of the blink reflex traverses an oligosynaptic pathway, this MRI study does not support the view that synaptic transmission in the PSN subserves R1. The reflex arc probably descends more medially and ventrally on its course to the facial nucleus. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1327–1331, 2001
Relation between in vivo and in vitro measurements of skeletal muscle oxidative metabolism
Authors: Larson‐Meyer D. Enette , Newcomer Bradley R. , Hunter Gary R. , Joanisse Denis R. , Weinsier Roland L. , Bamman Marcas M. 
Published: August 2002

AbstractThe relationships between in vivo 31P magnetic resonance spectroscopy (MRS) and in vitro markers of oxidative capacity (mitochondrial function) were determined in 27 women with varying levels of physical fitness. Following 90‐s isometric plantar flexion exercises, calf muscle mitochondrial function was determined from the phosphocreatine (PCr) recovery time constant, the adenosine diphosphate (ADP) recovery time constant, the rate of change of PCr during the initial 14 s of recovery, and the apparent maximum rate of oxidative adenosine triphosphate (ATP) synthesis (Qmax). Muscle fiber type distribution (I, IIa, IIx), citrate synthase (CS) activity, and cytochrome c oxidase (COX) activity were determined from a biopsy sample of lateral gastrocnemius. MRS markers of mitochondrial function correlated moderately (P < 0.05) with the percentage of type IIa oxidative fibers (r = 0.41 to 0.66) and CS activity (r = 0.48 to 0.64), but only weakly with COX activity (r = 0.03 to 0.26, P > 0.05). These results support the use of MRS to determine mitochondrial function in vivo. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1665–1676, 2001