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Gadolinium
Terms modified by Gadolinium Selected AbstractsUSE OF HIGH-DOSE GADOLINIUM AS CONTRAST MEDIA TO AVOID RADIOCONTRAST MEDIA-INDUCED NEPHROPATHYJOURNAL OF RENAL CARE, Issue 1 2009Prajej Ruangkanchanasetr SUMMARY Patients at risk for radiocontrast media-induced nephropathy (RCIN) with suspected peripheral vascular disease were evaluated with high-dose (0.4 mmol/kg) gadolinium-based (Gd) contrast angiography (AG). The patients who were considered susceptible to RCIN were defined by having one or more of the following: (1) pre-existing serum creatinine (SCr) >124 ,mol/l, (2) diabetes mellitus and (3) age >60 years. An increase in SCr , 44 ,mol/l or , 25% of baseline was considered significant. Ten patients underwent peripheral AG using a high dose of Gd without any adverse reaction. The mean age was 67.8 years. Nine (90%) patients were diabetic. The quality of these images was satisfactory for diagnosis in eight out of 10 patients. None of these patients had significant change in SCr. The mean SCr (±SD) before, at 48 hours and at 72 hours after AG were 182 ± 97, 177 ± 99 and 177 ± 98 ,mol/l, respectively. Based on this limited study, Gd is a promising agent for peripheral angiographic study. In patients at risk for RCIN, the high dose of Gd appears to be safe without obvious nephrotoxicity. [source] Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motilityCYTOSKELETON, Issue 4 2003Zoltán Krasznai Abstract Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin,Ca2+ interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 ± 3% to 6 ± 3% and that of carp sperm from 91 ± 7% to 3.5 ± 4.3% in a dose-dependent manner (10,40 ,M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm. Cell Motil. Cytoskeleton 55:232,243, 2003. © 2003 Wiley-Liss, Inc. [source] Molecular Interaction between a Gadolinium,Polyoxometalate and Human Serum AlbuminEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 34 2009Li Zheng Abstract Polyoxometalates (POMs) show promising antibacterial, antiviral (particularly anti-HIV), antitumor, and anticancer activities, but the mechanism of these potential therapeutic effects remains to be elucidated at the molecular level. The interaction between the Gd-containing tungstosilicate [Gd(,2 -SiW11O39)2]13, and human serum albumin (HSA) was studied by several techniques. Fluorescence spectroscopy showed an energy transfer between the single tryptophan residue of HSA and the POM. Circular dichroism led to the conclusion that the POM significantly altered the secondary structure of HSA. Isothermal titration calorimetry revealed an enthalpy-driven binding reaction between HSA and the POM, resulting in the formation of a 1:1 complex.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Gadolinium , is it to blame?JOURNAL OF CUTANEOUS PATHOLOGY, Issue 5 2008Shawn E. Cowper [source] Gadolinium-based contrast agents and their potential role in the pathogenesis of nephrogenic systemic fibrosis: The role of excess ligandJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2008Martin A. Sieber PhD Abstract Purpose To investigate the role of excess ligand present in gadolinium (Gd) -based contrast agents in the development of nephrogenic systemic fibrosis (NSF). Using a dosing regimen to simulate the exposure seen in patients with severe renal impairment, we investigated the effect of excess ligand on Gd-deposition and the depletion of endogenous ions. Materials and Methods Gadodiamide and gadoversetamide were formulated with 0%, 5%, and 10% excess ligand. Forty-two, healthy, male Hannover Wistar rats received daily intravenous injections of each formulation over a period of 20 days. At the end of the study, histopathological analysis of the skin was performed and the concentrations of Gd, Zn, and Cu were measured in several tissues. The levels of Zn in the urine were also measured. Results The most severe skin lesions were observed after injection of formulations containing 0% free ligand and in those animals with the highest Gd concentrations in the skin. There were no significant reductions in the levels of Zn or Cu observed in the skin; however, the levels of Zn in the urine were elevated following administration of formulations with the highest amount of excess ligand. Conclusion Our findings suggest that there is an inverse correlation between the amount of excess ligand present in Gd-containing contrast agents and the amount of Gd in the tissue, and further underline the importance of the inherent stability of these agents in the development of NSF. J. Magn. Reson. Imaging 2008;27:955,962. © 2008 Wiley-Liss, Inc. [source] How accurate is dynamic contrast-enhanced MRI in the assessment of renal glomerular filtration rate?JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2008A critical appraisal Abstract Purpose To evaluate the current literature to see if the published results of MRI-glomerular filtration rate (GFR) stand up to the claim that MRI-GFR may be used in clinical practice. Claims in the current literature that Gadolinium (Gd) DTPA dynamic contrast enhanced (DCE) MRI clearance provides a reliable estimate of glomerular filtration are an overoptimistic interpretation of the results obtained. Before calculating absolute GFR from Gd-enhanced MRI, numerous variables must be considered. Materials and Methods We examine the methodology in the published studies on absolute quantification of MRI-GFR. The techniques evaluated included the dose and volume of Gd-DTPA used, the speed of injection, acquisition sequences, orientation of the subject, re-processing, conversion of signal to concentration and the model used for analysis of the data as well as the MRI platform. Results Claims in the current literature that using DCE MRI "Gd DTPA clearance provides a good estimate of glomerular filtration" are not supported by the data presented and a more accurate conclusion should be that "no MRI approach used provides a wholly satisfactory measure of renal GFR function." Conclusion This study suggests that DCE MRI-GFR results are not yet able to be used as a routine clinical or research tool. The published literature does not show what change in DCE MRI-GFR is clinically significant, nor do the results in the literature allow a single DCE MRI-GFR measurement to be correlated directly with a multiple blood sampling technique. J. Magn. Reson. Imaging 2008. © 2008 Wiley-Liss, Inc. [source] Electrical Properties of Gadolinium,Europium Zirconate CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010Xiao-Liang Xia (Gd1,xEux)2Zr2O7 (0,x,1.0) ceramics are prepared via a solid-state reaction process at 1973 K for 10 h in air. (Gd1,xEux)2Zr2O7 (0.2,x,1.0) ceramics exhibit an ordered pyrochlore-type structure; however, Gd2Zr2O7 has a disordered defect fluorite-type structure. Raman spectroscopy analysis indicates that the degree of structural ordering increases with the increase of Eu content. The electrical properties of (Gd1,xEux)2Zr2O7 ceramics are investigated using complex impedance spectroscopy over a frequency range of 0.1 Hz to 20 MHz from 623 to 923 K. Electrical conductivity obeys the Arrhenius equation. Both the activation energy and the preexponential factor for grain conductivity decrease with increasing europium content from Gd2Zr2O7 (x=0) to Eu2Zr2O7 (x=1.0). The measured electrical conductivity of (Gd1,xEux)2Zr2O7 ceramics increases with increasing Eu content and temperature. Electrical conductivity of the pyrochlore-type materials is higher than that of the defect fluorite-type material in (Gd1,xEux)2Zr2O7 solid solution systems. The electrical conductivity of (Gd0.4Eu0.6)2Zr2O7 is almost independent of oxygen partial pressure from 1.0 × 10,4 to 1.0 atm. The high ionic transference number of (Gd0.4Eu0.6)2Zr2O7 ceramic at different temperatures proves that conduction is purely ionic with negligible electronic contribution. [source] Gadolinium and nephrogenic systemic fibrosis: Association or causation (Review Article)NEPHROLOGY, Issue 3 2008JAGADEESH KURTKOTI SUMMARY: With widespread availability of magnetic resonance imaging (MRI), it has become standard practice for patients with severe renal impairment or previous severe reactions to iodine-containing contrast media to receive gadolinium-based MRI contrast agents instead of traditional radiographic contrast agents, particularly for magnetic resonance angiography. However, there is growing concern about the use of gadolinium contrast agents in the presence of severe renal insufficiency, because of increasing reports of nephrogenic fibrosing dermopathy (NFD)/nephrogenic systemic fibrosis (NSF), associated with the exposure to certain gadolinium-containing contrast agents. In this review we explore the causal link between gadolinium exposure and NSF, using an established system of epidemiological criteria proposed by Bradford Hill. Though the current evidence makes gadolinium a strong suspect as an aetiologic agent for NSF in the presence of severe renal failure, the die is not cast yet. At this stage there needs to be cautious approach to the use of gadolinium-containing contrast agents in the presence of severe renal failure (glomerular filtration rate <30 mL/min per 1.73 m2). [source] Gadolinium inhibits group III but not group IV muscle afferent responses to dynamic exerciseTHE JOURNAL OF PHYSIOLOGY, Issue 4 2009Shawn G. Hayes Dynamic exercise has been shown to stimulate rapidly both group III and IV muscle afferents. The often rapid (i.e. 2 s) onset latencies of the group IV afferents is particularly surprising because these unmyelinated afferents are thought to respond to the gradual accumulation of metabolites signalling a mismatch between blood/oxygen demand and supply in exercising muscles. One explanation for the rapid onset to exercise by group IV afferents is that they are mechanosensitive, a concept that has been supported by the finding that these afferents were stimulated by vasodilatation induced by injection of vasoactive drugs. We therefore examined in decerebrated cats the effect of gadolinium, a blocker of mechanogated channels, on the responses of group III and IV muscle afferents to dynamic exercise induced by electrical stimulation of the mesencephalic locomotor region. We found that gadolinium (10 mm; 1 ml) injected into the abdominal aorta had no significant effect (P > 0.05) on the responses of 11 group IV afferents to dynamic exercise. In contrast, gadolinium markedly attenuated the responses of 11 group III afferents to exercise (P < 0.05). Our findings suggest that group IV afferents are not responding to a mechanical stimulus during exercise. Instead their rapid response to dynamic exercise might be caused by a chemical substance whose concentration is directly proportional to blood flow, which increases in the skeletal muscles when they are dynamically exercising. [source] Selective Aggregation of a Platinum,Gadolinium Complex Within a Tumor-Cell Nucleus,ANGEWANDTE CHEMIE, Issue 7 2010Ellen Per Anhalter in den Zellkern: Ein in DNA intercalierter Metallkomplex kann die selektive Ansammlung eines intakten Wirkstoffs in den Kernen von humanen Lungenkrebszellen (A549) ermöglichen. Mit einem Platinkomplex gelang es nun, auf diesem Weg Gadolinium in Zellkerne zu schleusen. Die Synchrotron-Röntgenfluoreszenz-Bildgebung diente zum Nachweis des Prozesses (siehe Bilder). [source] Review of imaging of scaphoid fracturesANZ JOURNAL OF SURGERY, Issue 1-2 2010Michael Smith Abstract Scaphoid fractures are the most common fractures of the carpus, accounting for 79% of all carpal fractures. Early diagnosis of scaphoid fractures is imperative owing to potential complications following the fracture, including non-union, avascular necrosis, carpal instability and osteoarthritis. Plain radiography remains the initial imaging modality to assess scaphoid fractures. Magnetic resonance imaging (MRI) is excellent in the detection of clinically suspected, but initially radiographically negative, scaphoid fractures. Cost-effectiveness analysis studies have demonstrated MRI is effective in this setting. Gadolinium enhanced MRI has been shown to be superior to unenhanced MRI in the detection of avascular necrosis. Computerized tomography scan is the preferred modality to assess the intricacies of scaphoid fracture, including fracture location and deformity, as well as union status. This review paper explores the recent advances in imaging of the scaphoid, with reference also to avascular necrosis and non-union following a scaphoid fracture. [source] Gadolinium-based balloon angioplasty for pulmonary artery stenosis in an infant with a right isomerismCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2004Hisashi Sugiyama MD Abstract We report here the first described case of utilizing gadolinium-based contrast material as the contrast agent during a catheter intervention treatment for pulmonary artery stenosis. The patient, a male infant with complex heart disease associated with a right isomerism, had a history of severe allergic reaction to iodine-containing contrast agents. A combination of digital subtraction angiography and a gadolinium contrast agent, however, provided us with good-quality images both before and after balloon angioplasty without any associated complications. This method should therefore be considered as an alternative angiographic procedure in children with a high risk of iodine-related allergic complications. Catheter Cardiovasc Interv 2004;63:346,350. © 2004 Wiley-Liss, Inc. [source] Hydration of Lanthanoid(III) Ions in Aqueous Solution and Crystalline Hydrates Studied by EXAFS Spectroscopy and Crystallography: The Myth of the "Gadolinium Break"CHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2008Ingmar Persson Prof. Abstract The structures of the hydrated lanthanoid(III) ions including lanthanum(III) have been characterized in aqueous solution and in the solid trifluoromethanesulfonate salts by extended X-ray absorption fine structure (EXAFS) spectroscopy. At ambient temperature the water oxygen atoms appear as a tricapped trigonal prism around the lanthanoid(III) ions in the solid nonaaqualanthanoid(III) trifluoromethanesulfonates. Water deficiency in the capping positions for the smallest ions starts at Ho and increases with increasing atomic number in the [Ln(H2O)9,x](CF3SO3)3 compounds with x=0.8 at Lu. The crystal structures of [Ho(H2O)8.91](CF3SO3)3 and [Lu(H2O)8.2](CF3SO3)3 were re-determined by X-ray crystallography at room temperature, and the latter also at 100,K after a phase-transition at about 190,K. The very similar Ln K- and L3 -edge EXAFS spectra of each solid compound and its aqueous solution indicate indistinguishable structures of the hydrated lanthanoid(III) ions in aqueous solution and in the hydrated trifluoromethanesulfonate salt. The mean LnO bond lengths obtained from the EXAFS spectra for the largest ions, La,Nd, agree with estimates from the tabulated ionic radii for ninefold coordination but become shorter than expected starting at samarium. The deviation increases gradually with increasing atomic number, reaches the mean LnO bond length expected for eightfold coordination at Ho, and increases further for the smallest lanthanoid(III) ions, Er,Lu, which have an increasing water deficit. The low-temperature crystal structure of [Lu(H2O)8.2](CF3SO3)3 shows one strongly bound capping water molecule (LuO 2.395(4),Å) and two more distant capping sites corresponding to LuO at 2.56(1),Å, with occupancy factors of 0.58(1) and 0.59(1). There is no indication of a sudden change in hydration number, as proposed in the "gadolinium break" hypothesis. [source] Gadolinium(III)-Loaded Nanoparticulate Zeolites as Potential High-Field MRI Contrast Agents: Relationship Between Structure and RelaxivityCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2005Éva Csajbók Dr. Abstract The effects of dealumination, pore size, and calcination on the efficiency (as expressed in the relaxivity) of Gd3+ -loaded zeolites for potential application as magnetic resonance imaging (MRI) contrast agents were studied. Partial dealumination of zeolites NaY or NaA by treatment with (NH4)2SiF6 or diluted HCl resulted in materials that, upon loading with Gd3+, had a much higher relaxivity than the corresponding non-dealuminated materials. Analysis of the 1H NMR dispersion profiles of the various zeolites showed that this can be mainly ascribed to an increase of the amount of water inside the zeolite cavities as a result of the destruction of walls between cavities. However, the average residence time of water inside the Gd3+ -loaded cavities did not change significantly, which suggests that the windows of the Gd3+ -loaded cavities are not affected by the dealumination. Upon calcination, the Gd3+ ions moved to the small sodalite cavities and became less accessible for water, resulting in a decrease in relaxivity. The important role of diffusion for the relaxivity was demonstrated by a comparison of the relaxivity of Gd3+ -loaded zeolite NaY and NaA samples. NaA had much lower relaxivities due to the smaller pore sizes. The transversal relaxivities of the Gd3+ -doped zeolites are comparable in magnitude to the longitudinal ones at low magnetic fields (<60 MHz). However at higher fields, the transversal relaxivities steeply increased, whereas the longitudinal relaxivities decreased as field strength increased. Therefore, these materials have potential as T1 MRI contrast agents at low field, and as T2 agents at higher fields. [source] Gadolinium-Based Mixed-Metal Nitride Clusterfullerenes GdxSc3,xN@C80 (x=1, 2),CHEMPHYSCHEM, Issue 9 2006Shangfeng Yang Dr. Abstract The first gadolinium-based mixed-metal nitride clusterfullerenes GdxSc3,xN@C80 (I) (1, x=2; 2, x=1) have been successfully synthesized by the reactive gas atmosphere method and isolated facilely by recycling high-performance liquid chromatography (HPLC). The sum yield of 1 and 2 is 30,40 times higher than that of Gd3N@C80 (I). Moreover, an enhanced relative yield of 2 over the Sc3N@C80 (I) is achieved under the optimized synthesis conditions. According to the UV/Vis/NIR spectroscopic characterization, 1 and 2 are both stable fullerenes with large optical band-gaps while 1 has higher similarity to Gd3N@C80 (I) and 2 resembles Sc3N@C80 (I). The vibrational structures of 1 and 2 are studied by Fourier-transform infrared (FTIR) spectroscopy as well as density functional theory (DFT) computations. In particular, the structures of the encaged GdxSc3,xN clusters within 1 and 2 are analyzed. [source] MR imaging in assessing cardiovascular interventions and myocardial injuryCONTRAST MEDIA & MOLECULAR IMAGING, Issue 1 2007Alexis Jacquier Abstract Performing an MR-guided endovascular intervention requires (1) real-time tracking and guidance of catheters/guide wires to the target, (2) high-resolution images of the target and its surroundings in order to define the extent of the target, (3) performing a therapeutic procedure (delivery of stent or injection of gene or cells) and (4) evaluating the outcome of the therapeutic procedure. The combination of X-ray and MR imaging (XMR) in a single suite was designed for new interventional procedures. MR contrast media can be used to delineate myocardial infarcts and microvascular obstruction, thereby defining the target for local delivery of therapeutic agents under MR-guidance. Iron particles, or gadolinium- or dysprosium-chelates are mixed with the soluble injectates or stem cells in order to track intramyocardial delivery and distribution. Preliminary results show that genes encoded for vascular endothelial and fibroblast growth factor and cells are effective in promoting angiogenesis, arteriogenesis, perfusion and LV function. Angiogenic growth factors, genes and cells administered under MR-guided minimally invasive catheter-based procedures will open up new avenues in treating end-stage ischemic heart disease. The optimum dose of the therapeutic agents, delivery devices and real-time imaging techniques to guide the delivery are currently the subject of ongoing research. The aim of this review is to (1) provide an updated review of experiences using MR imaging to guide transcatheter therapy, (2) address the potential of cardiovascular magnetic resonance (MR) imaging and MR contrast media in assessing myocardial injury at a molecular level and labeling cells and (3) illustrate the applicability of the non-invasive MR imaging in the field of angiogenic therapies through recent clinical and experimental publications. Copyright © 2007 John Wiley & Sons, Ltd. [source] CMR 2005: 1.02: Extraction rate of SPIO by the normal and gadolinium chloride-treated liverCONTRAST MEDIA & MOLECULAR IMAGING, Issue 2 2006S. Hirohashi [source] Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motilityCYTOSKELETON, Issue 4 2003Zoltán Krasznai Abstract Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin,Ca2+ interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 ± 3% to 6 ± 3% and that of carp sperm from 91 ± 7% to 3.5 ± 4.3% in a dose-dependent manner (10,40 ,M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm. Cell Motil. Cytoskeleton 55:232,243, 2003. © 2003 Wiley-Liss, Inc. [source] Magnetic Resonance Imaging in the Study of the Lithium,Pilocarpine Model of Temporal Lobe Epilepsy in Adult RatsEPILEPSIA, Issue 4 2002Catherine Roch Summary: ,Purpose: In temporal lobe epilepsy, it remains to be clarified whether hippocampal sclerosis is the cause or the consequence of epilepsy. We studied the temporal evolution of the lesions in the lithium,pilocarpine model of epilepsy in the rat with magnetic resonance imaging (MRI) to determine the progressive morphologic changes occurring before the appearance of chronic epilepsy. Methods: MRI was performed on an MR scanner operating at 4.7 T. We followed the evolution of lesions using T2 - and T1 -weighted sequences before and after the injection of gadolinium from 2 h to 9 weeks. Results: At 2 h after status epilepticus (SE), a blood,brain barrier breakdown could be observed only in the thalamus; it had disappeared by 6 h. At 24 h after SE, edema was present in the amygdala and the piriform and entorhinal cortices together with extensive neuronal loss; it disappeared progressively over a 5-day period. During the chronic phase, a cortical signal reappeared in all animals; this signal corresponded to gliosis, which appeared on glial fibrillary acidic protein (GFAP) immunohistochemically stained sections as hypertrophic astrocytes with thickened processes. In the hippocampus, the correlation between histopathology and T2 -weighted signal underscored the progressive constitution of atrophy and sclerosis, starting 2 days after SE. Conclusions: These data show the reactivity of the cortex that characterizes the initial step leading to the development of epilepsy and the late gliosis that could result from the spontaneous seizures. Moreover, it appears that hippocampal sclerosis progressively worsened and could be both the cause and the consequence of epileptic activity. [source] Magnetic Resonance Imaging Follow-up of Progressive Hippocampal Changes in a Mouse Model of Mesial Temporal Lobe EpilepsyEPILEPSIA, Issue 6 2000Viviane Bouilleret Summary: Purpose: Hippocampal sclerosis (HS) is the most frequent lesion found in mesial temporal lobe epilepsy (mTLE). MR imaging is considered to be the most sensitive and specific method to detect HS. Despite extensive studies performed on humans and except in a recent study, the morphologic pattern of HS is usually analyzed when the disease has already fully developed, thus not allowing any insight into the mapping of the progressive morphologic changes inducing the development of mTLE. We have recently characterized a model of mTLE that reproduces the unilateral pattern of HS, induced by intrahippocampal injection of low doses of kainate (KA) in mice. Methods: In this study, we monitored the temporal evolution of the development of HS in this model of mTLE by using T2 -weighted sequence, T2 -relaxation time measurements, and T1 -weighted spin-echo technique after injection of gadolinium, from 1 h to 120 days after KA injection. Results: HS induced by intrahippocampal KA injection occurred in two phases. First, we observed a transient hyperintense T2 -weighted signal in the cortex above the injected hippocampus, most likely indicative of vasogenic edema partly due to the neurotoxic effect of KA. The concomitant increase in the T2 signal in the injected hippocampus and ipsilateral amygdala likely reflects the phase of cytotoxic edema occurring probably in relation to the excitotoxic consequences of both KA and seizure activity. Second, from 15 days on, a persistent unilateral increased T2 signal was detected in the hippocampus, which most probably reflects gliosis. Conclusions: Our findings indicate that longitudinal follow-up would permit a better understanding of the mechanisms underlying the constitution of HS in humans and eventually development of prevention strategies. [source] Eight-Coordinate Endohedral Rhenium, Osmium and Iridium Atoms in Rare-Earth Halide Cluster ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2010Sina Zimmermann Abstract Endohedral (interstitial) atoms are essential for almost all of the rare-earth halide cluster complexes. Most of these contain octahedral clusters, some are isolated, but the majority exhibits condensation by common edges to structures of higher dimensionality. Higher coordination numbers of the endohedral atoms are rare. Four examples of extended cluster complexes with eight-coordinate endohedral atoms of sixth-period elements (Re, Os, Ir) are presented. In the quasi-isostructural, non-isotypic halides {ReGd4}Br4 and {OsSc4}Cl4, square antiprisms of gadolinium and scandium atoms, respectively, are connected by two common faces to chains, surrounded and loosely connected by halogenido ligands. The Re and Os atoms build a slightly bent chain with only little bonding interactions. Chemical bonding is dominated by endohedral atom,cluster atom and cluster atom,halide interactions. The same is true for the two scandium bromides {Ir3Sc12}Br16 and {Os3Sc12}Br16Sc, which contain chains of face-sharing square antiprisms and cubes in a ratio of 2:1. Metal,metal bonding is attested by short distances between those endohedral Ir and Os atoms, respectively, which center the square antiprisms (283 pm and 290 pm, respectively). Magnetic and conductivity measurements on {Ir3Sc12}Br16 reveal paramagnetism and a small-band-gap semiconductor. This is in accord with electronic structure calculations. [source] Transient receptor potential A1 mediates acetaldehyde-evoked pain sensationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2007Sangsu Bang Abstract Six transient receptor potential (TRP) ion channels expressed in the sensory afferents play an important role as body thermosensors and also as peripheral pain detectors. It is known that a number of natural compounds specifically activate those sensory neuronal TRP channels, and a well-known example is cinnamaldehyde for TRPA1. Here we show that human and mouse TRPA1 are activated by acetaldehyde, an intermediate substance of ethanol metabolism, in the HEK293T cell heterologous expression system and in cultured mouse trigeminal neurons. Acetaldehyde failed to activate other temperature-sensitive TRP channels expressed in sensory neurons. TRPA1 antagonists camphor and gadolinium, and a general TRP blocker ruthenium red inhibited TRPA1 activation by acetaldehyde. Camphor, gadolinium and ruthenium red also suppressed the acute nociceptive behaviors induced by the intradermal administration of acetaldehyde into the mouse footpads. Intradermal co-application of prostaglandin E2 and acetaldehyde greatly potentiated the acetaldehyde-induced nociceptive responses, and this effect was reversed by treatment with the TRPA1 antagonist camphor. These results suggest that acetaldehyde causes nociception via TRPA1 activation. Our data may also help elucidate the mechanisms underlying acetaldehyde-related pathological symptoms such as hangover pain. [source] Calcium and polyamine regulated calcium-sensing receptors in cardiac tissuesFEBS JOURNAL, Issue 12 2003Rui Wang Activation of a calcium-sensing receptor (Ca-SR) leads to increased intracellular calcium concentration and altered cellular activities. The expression of Ca-SR has been identified in both nonexcitable and excitable cells, including neurons and smooth muscle cells. Whether Ca-SR was expressed and functioning in cardiac myocytes remained unclear. In the present study, the transcripts of Ca-SR were identified in rat heart tissues using RT-PCR that was further confirmed by sequence analysis. Ca-SR proteins were detected in rat ventricular and atrial tissues as well as in isolated cardiac myocytes. Anti-(Ca-SR) Ig did not detect any specific bands after preadsorption with standard Ca-SR antigens. An immunohistochemistry study revealed the presence of Ca-SR in rat cardiac as well as other tissues. An increase in extracellular calcium or gadolinium induced a concentration-dependent sustained increase in [Ca2+]i in isolated ventricular myocytes from adult rats. Spermine (1,10 mm) also increased [Ca2+]i. Pre-treatment of cardiac myocytes with thapsigargin or U73122 abolished the extracellular calcium, gadolinium or spermine-induced increase in [Ca2+]i. The blockade of Na+/Ca2+ exchanger or voltage-dependent calcium channels did not alter the extracellular calcium-induced increase in [Ca2+]i. Finally, extracellular calcium, gadolinium and spermine all increased intracellular inositol 1,4,5-triphosphate (IP3) levels. Our results demonstrated that Ca-SR was expressed in cardiac tissue and cardiomyocytes and its function was regulated by extracellular calcium and spermine. [source] Determination of Ti, K, Sm and Gd Values in Geological Survey of Japan Reference Materials by Prompt Gamma Neutron Activation AnalysisGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2006Takashi Sano activation neutronique et comptage gamma; GSJ; roches ignées; samarium gadolinium Prompt gamma neutron activation analysis was applied to the determination of the titanium, potassium, samarium and gadolinium contents of nine Geological Survey of Japan (GSJ) reference materials (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Firstly, the values in JB-1 were determined by the standard addition method: pressed powder disks of JB-1 were used for neutron irradiation and gamma-ray measurements, after known quantities of standard reagents had been added. Secondly, the contents of eight other reference materials were determined by comparison methods using JB-1 as the comparative standard. The precision of analyses were obtained by replicate determinations on these samples. The relative standard deviation was generally less than 5%. For most samples, analysed values agreed well (< 5%) with the recommended values. L'analyse par activation neutronique et comptage des particules gamma rapide a été appliquée à la détermination des concentrations en titane, potassium, samarium et gadolinium de neuf matériaux de référence du Service Géologique du Japon (GSJ) : (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Tout d'abord les teneurs dans JB-1 ont été déterminées par la technique de l'addition de standard : des pastilles de poudre compressée de JB-1 ont été irradiées par un flux neutronique puis la mesure des émissions gamma, a été effectuée après que des quantités connues de réactifs standards aient été ajoutées. Ensuite les teneurs dans les huit autres ont été déterminées en utilisant JB-1 comme standard de calibration. La précision des analyses a été déterminée en dupliquant les analyses de ces échantillons. Les déviations standard relatives étaient généralement de moins de 5%. Pour la plupart des échantillons les teneurs déterminées sont en bon accord (< 5%) avec les valeurs recommandées. [source] Acute Intracranial Hemorrhage in the Brain Caused by AcupunctureHEADACHE, Issue 5 2000Daniel Chung Ann Choo MD A 44-year-old Chinese man developed severe occipital headache, nausea, and vomiting during acupuncture treatment of the posterior neck for chronic neck pain. Computed tomography of the head showed hemorrhage in the fourth, third, and lateral ventricles. A lumbar puncture confirmed the presence of blood. Magnetic resonance angiography with gadolinium did not reveal any saccular aneurysms or arteriovenous malformations. The patient's headache resolved over a period of 28 days without any neurological deficits. Acupuncture of the posterior neck can cause acute intracranial hemorrhage. [source] Cover Picture: Synthesis of Gadolinium-Labeled Shell-Crosslinked Nanoparticles for Magnetic Resonance Imaging Applications (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 8 2005Mater. Abstract Robust, amphiphilic core,shell nanoparticles that are selectively labeled with gadolinium in the hydrophilic and water-swollen shell layer are depicted in the cover picture. These well-defined nanostructured materials exhibit high relaxivity, a large loading capacity, and are based upon a biocompatible platform for ultimate function in magnetic resonance imaging (MRI) applications, as reported by Wooley and co-workers on p.,1248. Shell-crosslinked knedel-like nanoparticles (SCKs; "knedel" is a Polish term for dumplings) were derivatized with gadolinium chelates and studied as robust magnetic-resonance-imaging-active structures with hydrodynamic diameters of 40,±,3,nm. SCKs possessing an amphiphilic core,shell morphology were produced from the aqueous assembly of diblock copolymers of poly-(acrylic acid) (PAA) and poly(methyl acrylate) (PMA), PAA52,b,PMA128, and subsequent covalent crosslinking by amidation upon reaction with 2,2,-(ethylenedioxy)bis(ethylamine) throughout the shell layer. The properties of these materials, including non-toxicity towards mammalian cells, non-immunogenicity within mice, and capability for polyvalent targeting, make them ideal candidates for utilization within biological systems. The synthesis of SCKs derivatized with GdIII and designed for potential use as a unique nanometer-scale contrast agent for MRI applications is described herein. Utilization of an amino-functionalized diethylenetriaminepentaacetic acid,Gd analogue allowed for direct covalent conjugation throughout the hydrophilic shell layer of the SCKs and served to increase the rotational correlation lifetime of the Gd. In addition, the highly hydrated nature of the shell layer in which the Gd was located allowed for rapid water exchange; thus, the resulting material demonstrated large ionic relaxivities (39,s,1,mM,1) in an applied magnetic field of 0.47,T at 40,°C and, as a result of the large loading capacity of the material, also demonstrated high molecular relaxivities (20,000,s,1,mM,1). [source] Cold liver ischemia-reperfusion injury critically depends on liver T cells and is improved by donor pretreatment with interleukin 10 in miceHEPATOLOGY, Issue 6 2000Olivier Le Moine M.D. Kupffer cells are thought to mediate most of the deleterious effects of liver ischemia-reperfusion injury. The role of liver T cells and the impact of resident cell deactivation by interleukin 10 (IL-10) have never been addressed. Using a model of ex vivo liver cold ischemia and reperfusion, we assessed liver injury, tumor necrosis factor (TNF) and interferon gamma (IFN-,) release from livers of balb/c mice, nude mice, nude mice reconstituted with T cells, and gadolinium balb/c pretreated mice. The anti-inflammatory cytokine IL-10 was then used to define the best strategy of administration potentially able to modulate ischemia-reperfusion injury. For this purpose IL-10 was administered to the donor before liver harvesting, in the preservation medium during cold ischemia or during reperfusion. TNF and IFN-, were released time dependently and paralleled liver injury after reperfusion of cold preserved livers. Reperfused livers from nude or gadolinium pretreated mice disclosed a dramatic decrease in TNF and IFN-, release. Tissue injury was reduced by 51% in the absence of T cells and by 88% when Kupffer cells were deactivated. This effect was reverted by T-cell transfer to nude mice. Only donor pretreatment with IL-10 or IL-10 infusion during reperfusion led to a significant decrease in liver injury, TNF, and IFN-, release (,66% or ,41%, ,95% or ,94%, and ,70% or ,70%, respectively). In conclusion, liver resident T cells are critically involved in cold ischemia-reperfusion injury and pretreatment of the donor with IL-10 decreases liver injury and the release of T-cell, and macrophage-dependent cytokines. [source] Diagnosis of pancreatic cancerHPB, Issue 5 2006Fumihiko Miura Abstract The ability to diagnose pancreatic carcinoma has been rapidly improving with the recent advances in diagnostic techniques such as contrast-enhanced Doppler ultrasound (US), helical computed tomography (CT), enhanced magnetic resonance imaging (MRI), and endoscopic US (EUS). Each technique has advantages and limitations, making the selection of the proper diagnostic technique, in terms of purpose and characteristics, especially important. Abdominal US is the modality often used first to identify a cause of abdominal pain or jaundice, while the accuracy of conventional US for diagnosing pancreatic tumors is only 50,70%. CT is the most widely used imaging examination for the detection and staging of pancreatic carcinoma. Pancreatic adenocarcinoma is generally depicted as a hypoattenuating area on contrast-enhanced CT. The reported sensitivity of helical CT in revealing pancreatic carcinoma is high, ranging between 89% and 97%. Multi-detector-row (MD) CT may offer an improvement in the early detection and accurate staging of pancreatic carcinoma. It should be taken into consideration that some pancreatic adenocarcinomas are depicted as isoattenuating and that pancreatitis accompanied by pancreatic adenocarcinoma might occasionally result in the overestimation of staging. T1-weighted spin-echo images with fat suppression and dynamic gradient-echo MR images enhanced with gadolinium have been reported to be superior to helical CT for detecting small lesions. However, chronic pancreatitis and pancreatic carcinoma are not distinguished on the basis of degree and time of enhancement on dynamic gadolinium-enhanced MRI. EUS is superior to spiral CT and MRI in the detection of small tumors, and can also localize lymph node metastases or vascular tumor infiltration with high sensitivity. EUS-guided fine-needle aspiration biopsy is a safe and highly accurate method for tissue diagnosis of patients with suspected pancreatic carcinoma. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been suggested as a promising modality for noninvasive differentiation between benign and malignant lesions. Previous studies reported the sensitivity and specificity of FDG-PET for detecting malignant pancreatic tumors as being 71,100% and 64,90%, respectively. FDG-PET does not replace, but is complementary to morphologic imaging, and therefore, in doubtful cases, the method must be combined with other imaging modalities. [source] Gadolinium-enhanced magnetic resonance imaging.INFLAMMATORY BOWEL DISEASES, Issue 2 2004A useful radiological tool in diagnosing pediatric IBD Abstract Background Recent advances in gadolinium-enhanced magnetic resonance imaging (G-MRI) have been developed to enhance the resolution of the intestinal mucosa and facilitate the differentiation of ulcerative colitis (UC) from Crohn's disease (CD). The objective of this study is to apply this technology in Pediatrics. Methods A G-MRI was performed on 58 consecutive children with suspected IBD between 1999 and 2002 using intravenous gadolinium, fat suppression, and respiration-suspended sequences to enhance the resolution of the intestinal wall. The sensitivity and specificity in diagnosing either UC or CD was determined by comparing the G-MRI to the established histologic diagnosis. Results G-MRI confirmed the diagnosis of either CD (21) or UC (7) with a sensitivity and specificity of 96% and 92%, respectively. Among the 21 patients with CD, 14 showed proximal small bowel involvement by G-MRI. In total, 17 patients were diagnosed with indeterminate colitis (IC) based on histologic criteria alone, and among these patients, G-MRI had a significantly lower non-classification rate (P < 0.02). In comparison, endoscopy was less sensitive (57%), but more specific (100%) than either histology or G-MRI in diagnosing IBD. G-MRI also showed a strong concordance with computed tomography in diagnosing CD (P = 0.001). Conclusion G-MRI is a both a sensitive and specific radiologic tool in diagnosing pediatric IBD. In patients with CD, G-MRI may be useful in identifying proximal small bowel involvement. Longitudinal follow-up studies are needed in those patients diagnosed with IC to determine the predictive value of G-MRI testing. [source] Gadolinium-Induced Nephrogenic Systemic Fibrosis Is Associated with Insoluble Gd Deposits in Tissues: In Vivo Transmetallation Confirmed by MicroanalysisJOURNAL OF CUTANEOUS PATHOLOGY, Issue 12 2009Charu Thakral Background: Nephrogenic systemic fibrosis (NSF) is an extremely debilitating systemic fibrosing disorder affecting renal failure patients. The association of NSF with gadolinium (Gd) containing magnetic resonance contrast agents was noted in 2006. Gd deposition in skin biopsies was demonstrated shortly thereafter. Methods: We used automated scanning electron microscopy (SEM)/energy dispersive x-ray spectroscopy for in situ quantitative analysis of insoluble Gd-containing deposits, recording multi-elemental composition and spatial distribution of detected features. Results: Gd was detected in all 29 patients (53 of 57 skin biopsies) with NSF, biopsied from 2 weeks to 3 years after Gd exposure. Gd concentration ranged from 1 to 2270 cps/mm2 and was detected predominantly in the deep dermis and subcutaneous fibrous septa. Gd was found associated with Ca, P and sometimes Fe or Zn. Patients with sequential biopsies showed persistence or increase of Gd in tissues (6 of 11). Transmission electron microscopy (TEM) identified the intracellular deposits in fibrocytes and macrophages. Conclusions: The demonstration of insoluble tissue deposits of Gd with co-associated elements clearly confirms in vivo transmetallation and dissociation of soluble Gd-chelates. Toxic Gd3+ may trigger fibrosis under permissive conditions, e.g., in renal insufficiency. Pathologists and clinicians need to be aware of this serious but preventable disease. [source] | |||||||||||||||||||||||||||||||||||||||||||