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Sample records for gadolinium chelate assessment

  1. Gadolinium retention after administration of contrast agents based on linear chelators and the recommendations of the European Medicines Agency

    International Nuclear Information System (INIS)

    Dekkers, Ilona A.; Roos, Rick; Molen, Aart J. van der

    2018-01-01

    The Pharmacovigilance Risk Assessment Committee (PRAC) of the European Medicines Agency (EMA) earlier this year recommended to suspend some marketing authorisations for Gadolinium Containing Contrast Agents (GCCAs) based on linear chelators due to the potential risk of gadolinium retention in the human body. These recommendations have recently been re-evaluated by EMA's Committee for Medicinal Products for Human Use (CHMP), and confirmed the final opinion of the European Medicines Agency. This editorial provides an overview of the available GCCAs and summarises the recent evidence of gadolinium retention. Moreover, a critical appraisal of the strengths and limitations of the scientific evidence currently available on gadolinium retention is given. (orig.)

  2. Reaction of gadolinium chelates with ozone and hydroxyl radicals.

    Science.gov (United States)

    Cyris, Maike; Knolle, Wolfgang; Richard, Jessica; Dopp, Elke; von Sonntag, Clemens; Schmidt, Torsten C

    2013-09-03

    Gadolinium chelates are used in increasing amounts as contrast agents in magnetic resonance imaging, and their fate in wastewater treatment has recently become the focus of research. Oxidative processes, in particular the application of ozone, are currently discussed or even implemented for advanced wastewater treatment. However, reactions of the gadolinium chelates with ozone are not yet characterized. In this study, therefore, rate constants with ozone were determined for the three commonly used chelates Gd-DTPA, Gd-DTPA-BMA, and Gd-BT-DO3A, which were found to be 4.8 ± 0.88, 46 ± 2.5, and 24 ± 1.5 M(-1) s(-1), respectively. These low rate constants indicate that a direct reaction with ozone in wastewater is negligible. However, application of ozone in wastewater leads to substantial yields of (•)OH. Different methods have been applied and compared for determination of k((•)OH+Gd chelate). From rate constants determined by pulse radiolysis experiments (k((•)OH+Gd-DTPA) = 2.6 ± 0.2 × 10(9) M(-1) s(-1), k((•)OH+Gd-DTPA-BMA) = 1.9 ± 0.7 × 10(9) M(-1) s(-1), k((•)OH+Gd-BT-DO3A) = 4.3 ± 0.2 × 10(9) M(-1) s(-1)), it is concluded that a reaction in wastewater via (•)OH radicals is feasible. Toxicity has been tested for educt and product mixtures of both reactions. Cytotoxicity (MTT test) and genotoxicity (micronuclei assay) were not detectable.

  3. Advantages of gadolinium based ultrasmall nanoparticles vs molecular gadolinium chelates for radiotherapy guided by MRI for glioma treatment

    OpenAIRE

    Le Duc, G.; Roux, S.; Paruta-Tuarez, A.; Dufort, S.; Bräuer, E.; Marais, A.; Truillet, C.; Sancey, L.; Perriat, P.; Lux, F.; Tillement, O.

    2014-01-01

    AGuIX nanoparticles are formed of a polysiloxane network surrounded by gadolinium chelates. They present several characteristics. They are easy to produce, they present very small hydrodynamic diameters (

  4. Modeling systemic and renal gadolinium chelate transport with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Votaw, John R.; Martin, Diego [Emory University Hospital, Department of Radiology, Atlanta, GA (United States)

    2008-01-15

    The advent of modern MRI scanners and computer equipment permits the rapid sequential collection of images of gadolinium chelate (Gd) transit through the kidney. The excellent spatial and temporal (0.9 s) resolution permits analyzing the shape of the recovered curves with a sophisticated model that includes both space and time. The purpose of this manuscript is to present such a mathematical model. By building into the model significant physical processes that contribute to the shape of the measured curve, quantitative values can be assigned to important parameters. In this work, quantitative values are determined for blood dispersion through the cardio-pulmonary system, systemic clearance rate of Gd, blood flow into each kidney, blood transit time in each kidney, the extraction rate of Gd across the capillary membrane, interstitial distribution volume, and the GFR for each kidney. (orig.)

  5. Actual clinical use of gadolinium-chelates for non-MRI applications

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, Holger M; Schild, H [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, 53105, Bonn (Germany)

    2004-06-01

    For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO{sub 2} and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

  6. Actual clinical use of gadolinium-chelates for non-MRI applications

    International Nuclear Information System (INIS)

    Strunk, Holger M.; Schild, H.

    2004-01-01

    For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO 2 and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

  7. Possible involvement of gadolinium chelates in the pathophysiology of nephrogenic systemic fibrosis: A critical review

    International Nuclear Information System (INIS)

    Idee, Jean-Marc; Port, Marc; Medina, Christelle; Lancelot, Eric; Fayoux, Emmanuelle; Ballet, Sebastien; Corot, Claire

    2008-01-01

    Nephrogenic systemic fibrosis (NSF) is a recently described, highly debilitating scleroderma-like disease occurring in patients with severe or end-stage renal failure. NSF is characterized by cutaneous papules and coalescing plaques ('peau d'orange' appearance) and a wooden consistency. It may ultimately cause disabling contractures of several joints, thus making many patients wheelchair-dependent. NSF has been associated to prior administration of gadolinium chelates (GC) used as contrast agents for magnetic resonance imaging. The best available treatment option at the present time is renal transplantation. The mechanism of NSF has not been fully elucidated. Several hypotheses have been proposed so far and are critically discussed in the present review article. Gadolinium has been found in skin biopsy samples of patients. The most widely accepted hypothesis is related to dechelation of less stable GC, progressively releasing free Gd 3+ which may subsequently lead to the attraction of CD34+, CD45+, pro-collagen+ circulating fibrocytes via the release of chemokines, thereby inducing systemic fibrosing disorders. Pre-existing renal failure may facilitate the process by delaying the excretion of GC. A complex interplay between gadolinium and co-factors (pro-inflammatory status, vascular injury, high dose of erythropoietin, high levels of calcium, phosphorus, etc.) may occur in patients with impaired renal function. This and other hypotheses remain to be investigated, as well as the role and independence of co-factors

  8. Hybrid Calcium Phosphate-Polymeric Micelles Incorporating Gadolinium Chelates for Imaging-Guided Gadolinium Neutron Capture Tumor Therapy.

    Science.gov (United States)

    Mi, Peng; Dewi, Novriana; Yanagie, Hironobu; Kokuryo, Daisuke; Suzuki, Minoru; Sakurai, Yoshinori; Li, Yanmin; Aoki, Ichio; Ono, Koji; Takahashi, Hiroyuki; Cabral, Horacio; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2015-06-23

    Gadolinium (Gd) chelates-loaded nanocarriers have high potential for achieving magnetic resonance imaging (MRI)-guided Gd neutron capture therapy (GdNCT) of tumors. Herein, we developed calcium phosphate micelles hybridized with PEG-polyanion block copolymers, and incorporated with the clinical MRI contrast agent Gd-diethylenetriaminepentaacetic acid (Gd-DTPA/CaP). The Gd-DTPA/CaP were nontoxic to cancer cells at the concentration of 100 μM based on Gd-DTPA, while over 50% of the cancer cells were killed by thermal neutron irradiation at this concentration. Moreover, the Gd-DTPA/CaP showed a dramatically increased accumulation of Gd-DTPA in tumors, leading to the selective contrast enhancement of tumor tissues for precise tumor location by MRI. The enhanced tumor-to-blood distribution ratio of Gd-DTPA/CaP resulted in the effective suppression of tumor growth without loss of body weight, indicating the potential of Gd-DTPA/CaP for safe cancer treatment.

  9. Use of gadolinium chelate to confirm epidural needle placement in patients with an iodinated contrast reaction

    International Nuclear Information System (INIS)

    Shetty, Sanjay K.; Nelson, Erik N.; Lawrimore, Tara M.; Palmer, William E.

    2007-01-01

    When performing epidural steroid injections for the management of chronic back pain, imaging guidance and a limited epidurogram improve accuracy of needle placement and ensure appropriate delivery of the injectate into the epidural space. We describe our experience using a gadolinium chelate as an alternative contrast agent for limited epidurography in patients with a history of an iodinated contrast reaction. Thirty-eight of 2,067 (1.8%) epidural steroid injections performed in our department over a 25-month period (December 2003-January 2006) employed gadolinium. All injections were performed in the lumbar spine employing a paramedian interlaminar approach. Procedural notes and patient charts were reviewed to evaluate for immediate or delayed complications related to incorrect intrathecal or intravascular needle placement. A retrospective analysis of selected fluoroscopic spot images was performed to evaluate confidence of epidural needle placement; this analysis compared these spot images against those obtained from age- and gender-matched control patients in whom iodinated contrast was used to confirm needle placement. Real-time fluoroscopic guidance permitted confident visualization of an epidurogram at the time of procedure in all 38 cases as documented in the procedural report, and no procedure resulted in a complication due to incorrect needle placement. Retrospective review of fluoroscopic spot images revealed at least moderate confidence of epidural needle placement by both readers in 29/38 cases (76.3%). Fluoroscopic spot images obtained using gadolinium yielded significantly less confidence than images obtained in control patients whose procedures were performed using iodinated contrast (P < 0.01). However, operators were sufficiently confident in needle placement based on real-time fluoroscopic images (not available in our subsequent review) to inject anesthestic in all 38 cases, despite the immediate consequences that could result from intrathecal

  10. Use of gadolinium chelate to confirm epidural needle placement in patients with an iodinated contrast reaction

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Sanjay K. [Massachusetts General Hospital, Harvard Medical School, Division of Musculoskeletal Radiology, Department of Radiology, Boston, MA (United States); Beth Israel Deaconess Medical Center, Harvard Medical School, Department of Radiology, Boston, MA (United States); Nelson, Erik N.; Lawrimore, Tara M.; Palmer, William E. [Massachusetts General Hospital, Harvard Medical School, Division of Musculoskeletal Radiology, Department of Radiology, Boston, MA (United States)

    2007-04-15

    When performing epidural steroid injections for the management of chronic back pain, imaging guidance and a limited epidurogram improve accuracy of needle placement and ensure appropriate delivery of the injectate into the epidural space. We describe our experience using a gadolinium chelate as an alternative contrast agent for limited epidurography in patients with a history of an iodinated contrast reaction. Thirty-eight of 2,067 (1.8%) epidural steroid injections performed in our department over a 25-month period (December 2003-January 2006) employed gadolinium. All injections were performed in the lumbar spine employing a paramedian interlaminar approach. Procedural notes and patient charts were reviewed to evaluate for immediate or delayed complications related to incorrect intrathecal or intravascular needle placement. A retrospective analysis of selected fluoroscopic spot images was performed to evaluate confidence of epidural needle placement; this analysis compared these spot images against those obtained from age- and gender-matched control patients in whom iodinated contrast was used to confirm needle placement. Real-time fluoroscopic guidance permitted confident visualization of an epidurogram at the time of procedure in all 38 cases as documented in the procedural report, and no procedure resulted in a complication due to incorrect needle placement. Retrospective review of fluoroscopic spot images revealed at least moderate confidence of epidural needle placement by both readers in 29/38 cases (76.3%). Fluoroscopic spot images obtained using gadolinium yielded significantly less confidence than images obtained in control patients whose procedures were performed using iodinated contrast (P < 0.01). However, operators were sufficiently confident in needle placement based on real-time fluoroscopic images (not available in our subsequent review) to inject anesthestic in all 38 cases, despite the immediate consequences that could result from intrathecal

  11. Combustion of gadolinium and dysprosium chelates as a cellular integrity marker in MR imaging

    International Nuclear Information System (INIS)

    Ericsson, A.; Bach-Gansmo, T.; Niklasson, F.; Hemmingsson, A.

    1995-01-01

    A combination of gadolinium (Gd) and dysprosium (Dy) chelates was investigated as a potential marker of cell-membrane integrity by means of a double-contrast effect in MR imaging. Blood samples with varying hematocrit (Hct) levels containing intact or lysed cells were used as model systems. With intact cells, the agents were assumed to be distributed solely extracellularly and the highest Hct studied (69%) was assumed to mimic the ratio of extracellular to intracellular water in tissue. The combined effect on image intensity of Gd (in a concentration corresponding to 0.2 mmol/kg b.w. in humans) and Dy (0.6 mmol/kg b.w.) applied simultaneously was a marked difference in signal intensity between samples with intact and lysed cells in both the T1- and T2-weighted spin-echo images with a corresponding increase in the contrast-to-noise ratio. This was the result of a T1 reduction caused by Gd with a negligible Dy susceptibility effect in areas with lysed cells. On the other hand, the Dy susceptibility effect (i.e. reduced apparent T2) dominated in areas with intact cells. Thus, the combination of Gd and Dy may serve as a marker of cell-membrane integrity in MR examinations. (orig.)

  12. Enhancement of the normal pancreas: comparison of manganese-DPDP and gadolinium chelate

    International Nuclear Information System (INIS)

    Kettritz, U.; Warshauer, D.M.; Brown, E.D.; Schlund, J.F.; Eisenberg, L.B.; Semelka, R.C.

    1996-01-01

    The purpose of this paper was to compare manganese-DPDP (Mn-DPDP) and gadolinium chelate (Gd-DTPA) contrast agents for enhancement of the normal pancreas. A total of 14 patients with focal liver disease underwent Mn-DPDP-and Gd-DTPA-enhanced 1.5 T MR examinations using spoiled gradient-echo (FLASH) technique at two separate times. Contrast agents were injected according to the currently recommended practices; Gd-DTPA was injected as a rapid bolus injection in a dosage of 0.1 mmol/kg, and Mn-DPDP was injected as a slow IV injection in a dosage of 5 μmol/kg. Quantitative region of interest measurements were made in 11 patients, and percent contrast enhancement of the pancreas and pancreas-fat signal-to-noise ratios (SNR) were determined for each agent. Images were also evaluated qualitativley by consensus reading of two investigators and overall scan quality was rated on a scale from 1 (poor) to 4 (very good). Enhancement of the pancreas immediately post Gd-DTPA was significantly higher than 15 min post Mn-DPDP (73.3 vs 36.3%; p=0.003). On postcontrast images the pancreas-fat SNR measruements were 7.7 (i.e., pancreas higher in signal than fat) and -6.1 for Gd-DTPA and Mn-DPDP, respectively, which was significantly different (p<0.001). Image quality was rated as 3.1 and 2.5 for Gd-DTPA- and Mn-DPDP-enhanced images, respectively. The normal pan creas enhances significantly more with Gd-DTPA than with Mn-DPDP administered under the conditions of this study. Overall image quality is also greater on the Gd-DTPA-enhanced images. (orig.)

  13. Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Gao, Xiaolong; Wang, Gangmin; Shi, Ting; Shao, Zhihong; Zhao, Peng; Shi, Donglu; Ren, Jie; Lin, Chao; Wang, Peijun

    2016-01-01

    Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T 1 -weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2′-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25 kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T 1 -weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. - Highlights: • Novel cationic gadolinium-chelated poly(urethane amide)s (GdCPUAs) are prepared. • GdCPUAs can induce a high transfection efficacy in different cancer cells. • GdCPUAs reveal good cyto-compatibility against cancer cells. • GdCPUAs may be applied as T 1 -contrast agents for magnetic resonance imaging. • GdCPUAs hold high potential for cancer theranostics.

  14. Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiaolong [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China); Wang, Gangmin [Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040 (China); Shi, Ting [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Shao, Zhihong [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China); Zhao, Peng; Shi, Donglu [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Ren, Jie [Institute of Nano and Biopolymeric Materials, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804 (China); Lin, Chao, E-mail: chaolin@tongji.edu.cn [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Wang, Peijun, E-mail: tjpjwang@sina.com [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China)

    2016-08-01

    Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T{sub 1}-weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2′-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25 kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T{sub 1}-weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. - Highlights: • Novel cationic gadolinium-chelated poly(urethane amide)s (GdCPUAs) are prepared. • GdCPUAs can induce a high transfection efficacy in different cancer cells. • GdCPUAs reveal good cyto-compatibility against cancer cells. • GdCPUAs may be applied as T{sub 1}-contrast agents for magnetic resonance imaging. • GdCPUAs hold high potential for cancer theranostics.

  15. N-acetylcysteine protects rats with chronic renal failure from gadolinium-chelate nephrotoxicity.

    Directory of Open Access Journals (Sweden)

    Leonardo Victor Barbosa Pereira

    Full Text Available The aim of this study was to evaluate the effect of Gd-chelate on renal function, iron parameters and oxidative stress in rats with CRF and a possible protective effect of the antioxidant N-Acetylcysteine (NAC. Male Wistar rats were submitted to 5/6 nephrectomy (Nx to induced CRF. An ionic-cyclic Gd (Gadoterate Meglumine was administrated (1.5 mM/KgBW, intravenously 21 days after Nx. Clearance studies were performed in 4 groups of anesthetized animals 48 hours following Gd- chelate administration: 1--Nx (n = 7; 2--Nx+NAC (n = 6; 3--Nx+Gd (n = 7; 4--Nx+NAC+Gd (4.8 g/L in drinking water, initiated 2 days before Gd-chelate administration and maintained during 4 days (n = 6. This group was compared with a control. We measured glomerular filtration rate, GFR (inulin clearance, ml/min/kg BW, proteinuria (mg/24 hs, serum iron (µg/dL; serum ferritin (ng/mL; transferrin saturation (%, TIBC (µg/dL and TBARS (nmles/ml. Normal rats treated with the same dose of Gd-chelate presented similar GFR and proteinuria when compared with normal controls, indicating that at this dose Gd-chelate is not nephrotoxic to normal rats. Gd-chelate administration to Nx-rats results in a decrease of GFR and increased proteinuria associated with a decrease in TIBC, elevation of ferritin serum levels, transferrin oversaturation and plasmatic TBARS compared with Nx-rats. The prophylactic treatment with NAC reversed the decrease in GFR and the increase in proteinuria and all alterations in iron parameters and TBARS induced by Gd-chelate. NAC administration to Nx rat did not modify the inulin clearance and iron kinetics, indicating that the ameliorating effect of NAC was specific to Gd-chelate. These results suggest that NAC can prevent Gd-chelate nephrotoxicity in patients with chronic renal failure.

  16. Value of 1.0-M gadolinium chelates: review of preclinical and clinical data on gadobutrol

    International Nuclear Information System (INIS)

    Tombach, Bernd; Heindel, Walter

    2002-01-01

    Several preclinical and clinical studies with the first commercially available highly concentrated Gd-chelate gadobutrol (1 mol/l) are reviewed. Physicochemical, pharmacological, and pharmacokinetic properties, safety analysis, as well as experimental and clinical efficacy studies are highlighted in comparison with 0.5-M Gd-chelates. The 1-mol gadobutrol has been proven to be safe in an examined dose range from 0.04 up to 0.5 mmol/kg body weight (b.w.). Even in patients with chronic renal impairment, including hemodialysis, gadobutrol can safely be applied at doses up to 0.3 mmol/kg b.w. For contrast-enhanced MRI in the equilibrium phase, efficacy data analysis shows comparable results to other commercially available extracellular Gd-chelates with lower Gd-concentrations (0.5 M). Studies focused on the potential benefit of a tighter bolus, such as brain perfusion imaging using T2*-effects, document the superiority of a highly concentrated Gd contrast agent. For contrast-enhanced MRA, clinical studies are still ongoing; therefore, the ultimate potential of a more compact bolus, using 1-M Gd-chelates, for contrast-enhanced MRI, has still to be analyzed, especially for time-resolved magnetic resonance angiography. (orig.)

  17. Magnetic Resonance Imaging of Therapy-Induced Necrosis Using Gadolinium-Chelated Polyglutamic Acids

    International Nuclear Information System (INIS)

    Jackson, Edward F.; Esparza-Coss, Emilio; Wen Xiaoxia; Ng, Chaan S.; Daniel, Sherita L.; Price, Roger E.; Rivera, Belinda; Charnsangavej, Chusilp; Gelovani, Juri G.; Li Chun

    2007-01-01

    Purpose: Necrosis is the most common morphologic alteration found in tumors and surrounding normal tissues after radiation therapy or chemotherapy. Accurate measurement of necrosis may provide an early indication of treatment efficacy or associated toxicity. The purpose of this report is to evaluate the selective accumulation of polymeric paramagnetic magnetic resonance (MR) contrast agents-gadolinium p-aminobenzyl-diethylenetriaminepentaacetic acid-poly(glutamic acid) (L-PG-DTPA-Gd and D-PG-DTPA-Gd)-in necrotic tissue. Methods and Materials: Two different solid tumor models, human Colo-205 xenograft and syngeneic murine OCA-1 ovarian tumors, were used in this study. Necrotic response was induced by treatment with poly(L-glutamic acid)-paclitaxel conjugate (PG-TXL). T 1 -weighted spin-echo images were obtained immediately and up to 4 days after contrast injection and compared with corresponding histologic specimens. Two low-molecular-weight contrast agents, DTPA-Gd and oligomeric(L-glutamic acid)-DTPA-Gd, were used as nonspecific controls. Results: Initially, there was minimal tumor enhancement after injection of either L-PG-DTPA-Gd or D-PG-DTPA-Gd, but rapid enhancement after injection of low-molecular-weight agents. However, polymeric contrast agents, but not low-molecular-weight contrast agents, caused sustained enhancement in regions of tumor necrosis in both tumors treated with PG-TXL and untreated tumors. These data indicate that high molecular weight, rather than in vivo biodegradation, is necessary for the specific localization of polymeric MR contrast agents to necrotic tissue. Moreover, biotinylated L-PG-DTPA-Gd colocalized with macrophages in the tumor necrotic areas, suggesting that selective accumulation of L- and D-PG-DTPA-Gd in necrotic tissue was mediated through residing macrophages. Conclusions: Our data suggest that MR imaging with PG-DTPA-Gd may be a useful technique for noninvasive characterization of treatment-induced necrosis

  18. Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

    Science.gov (United States)

    Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

    2014-01-01

    Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P = 0.0002) and a 43% reduction in total mortality (P = 0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

  19. Low-Molecular-Weight Iron Chelates May Be an Alternative to Gadolinium-based Contrast Agents for T1-weighted Contrast-enhanced MR Imaging.

    Science.gov (United States)

    Boehm-Sturm, Philipp; Haeckel, Akvile; Hauptmann, Ralf; Mueller, Susanne; Kuhl, Christiane K; Schellenberger, Eyk A

    2018-02-01

    Purpose To synthesize two low-molecular-weight iron chelates and compare their T1 contrast effects with those of a commercial gadolinium-based contrast agent for their applicability in dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging. Materials and Methods The animal experiments were approved by the local ethics committee. Two previously described iron (Fe) chelates of pentetic acid (Fe-DTPA) and of trans-cyclohexane diamine tetraacetic acid (Fe-tCDTA) were synthesized with stability constants several orders of magnitude higher than those of gadolinium-based contrast agents. The T1 contrast effects of the two chelates were compared with those of gadopentetate dimeglumine in blood serum phantoms at 1.5 T, 3 T, and 7 T. For in vivo studies, a human breast cancer cell line (MDA-231) was implanted in five mice per group. The dynamic contrast effects of the chelates were compared by performing DCE MR imaging with intravenous application of Fe-DTPA or Fe-tCDTA on day 1 and DCE MR imaging in the same tumors with gadopentetate dimeglumine on day 2. Quantitative DCE maps were generated with software and were compared by means of a one-tailed Pearson correlation test. Results Relaxivities in serum (0.94 T at room temperature) of Fe-tCDTA (r1 = 2.2 mmol -1 · sec -1 , r2 = 2.5 mmol -1 · sec -1 ) and Fe-DTPA (r1 = 0.9 mmol -1 · sec -1 , r2 = 0.9 mmol -1 · sec -1 ) were approximately twofold and fivefold lower, respectively, compared with those of gadopentetate dimeglumine (r1 = 4.1 mmol -1 · sec -1 , r2 = 4.8 mmol -1 · sec -1 ). Used at moderately higher concentrations, however, iron chelates generated similar contrast effects at T1-weighted MR imaging in vitro in serum, in vivo in blood, and for DCE MR imaging of breast cancer xenografts. The volume transfer constant values for Fe-DTPA and Fe-tCDTA in the same tumors correlated well with those observed for gadopentetate dimeglumine (Fe-tCDTA Pearson R, 0.99; P = .0003; Fe-DTPA Pearson R, 0.97; P

  20. Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

    International Nuclear Information System (INIS)

    Manwar, S.; Iram, S.

    2014-01-01

    Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

  1. Graphene Oxide and Gadolinium-Chelate Functionalized Poly(lactic acid) Nanocapsules Encapsulating Perfluorooctylbromide for Ultrasound/Magnetic Resonance Bimodal Imaging Guided Photothermal Ablation of Cancer.

    Science.gov (United States)

    Li, Zhenglin; Ke, Hengte; Wang, Jinrui; Miao, Zhaohua; Yue, Xiuli

    2016-03-01

    This paper successfully fabricated a novel multifunctional theranostic agent (PFOB@PLA/GO/Gd-DTPA NCs) by loading perfluorooctylbromide (PFOB) into poly(lactic acid) (PLA) nanocapsules (NCs) followed by surface functionalization with graphene oxide (GO) and gadolinium-chelate (Gd-DTPA). It was found that the resulting nanoagent could serve as a contrast agent simultaneously to enhance ultrasound (US) and magnetic resonance imaging (MRI). Benefiting from the strong absorption in the near infrared (NIR) region, the nanocapsules could efficiently kill cancer cells under NIR laser irradiation. Thus, such a single theranostic agent with the combination of realtime US imaging and high-resolution MR imaging could achieve great therapeutic effectiveness without systemic damage to the body. In addition, the cytotoxicity assay on HUVEC cells revealed a good biocompatibility of PFOB@PLA/GO/Gd-DTPA NCs, showing that the versatile nanocapsule system may hold great potential as an effective nanoplatform for contrast enhanced imaging guided photothermal therapy.

  2. Clinical, biological, and skin histopathologic effects of ionic macrocyclic and nonionic linear gadolinium chelates in a rat model of nephrogenic systemic fibrosis.

    Science.gov (United States)

    Fretellier, Nathalie; Idée, Jean-Marc; Guerret, Sylviane; Hollenbeck, Claire; Hartmann, Daniel; González, Walter; Robic, Caroline; Port, Marc; Corot, Claire

    2011-02-01

    the purpose of this study was to compare the clinical, pathologic, and biochemical effects of repeated administrations of ionic macrocyclic or nonionic linear gadolinium chelates (GC) in rats with impaired renal function. rats submitted to subtotal nephrectomy were allocated to single injections of 2.5 mmol/kg of gadodiamide (nonionic linear chelate), nonformulated gadodiamide (ie, without the free ligand caldiamide), gadoterate (ionic macrocyclic chelate), or saline for 5 consecutive days. Blinded semi-quantitative histopathologic and immunohistochemical examinations of the skin were performed, as well as clinical, hematological, and biochemical follow-up. Rats were killed at day 11. Long-term (up to day 32) follow-up of rats was also performed in an auxiliary study. epidermal lesions (ulcerations and scabs) were found in 4 of the 10 rats treated with nonformulated gadodiamide. Two rats survived the study period. Inflammatory signs were observed in this group. No clinical, hematological, or biochemical signs were observed in the saline and gadoterate- or gadodiamide-treated groups. Plasma fibroblast growth factor-23 levels were significantly higher in the gadodiamide group than in the gadoterate group (day 11). Decreased plasma transferrin-bound iron levels were measured in the nonformulated gadodiamide group. Histologic lesions were in the range: nonformulated gadodiamide (superficial epidermal lesions, inflammation, necrosis, and increased cellularity in papillary dermis) > gadodiamide (small superficial epidermal lesions and signs of degradation of collagen fibers in the dermis) > gadoterate (very few pathologic lesions, similar to control rats). repeated administration of the nonionic linear GC gadodiamide to renally impaired rats is associated with more severe histologic lesions and higher FGF-23 plasma levels than the macrocyclic GC gadoterate.

  3. Comparison of blood pool and extracellular gadolinium chelate for functional MR evaluation of vascular thoracic outlet syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ruth P., E-mail: ruthplim74@gmail.com [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Austin Health, Department of Radiology, Heidelberg, Victoria 3084 (Australia); The University of Melbourne, School of Medicine, Parkville, Victoria 3010 (Australia); Bruno, Mary, E-mail: mary.bruno@nyumc.org [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Rosenkrantz, Andrew B., E-mail: Andrew.rosenkrantz@nyumc.org [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Kim, Danny C., E-mail: danny.kim@nyumc.org [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Mulholland, Thomas, E-mail: Thomas.mulholland@nyumc.org [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Kwon, Jane, E-mail: jane.kwon@nyumc.org [New York University School of Medicine, Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, 660 1st Avenue, New York, NY 10016 (United States); Palfrey, Amy P., E-mail: amy.pastva10@stjohns.edu [St John' s University, Department of Psychology, 8000 Utopia Parkway, Jamaica-Queens, NY 11439 (United States); Ogedegbe, Olugbenga, E-mail: Olugbenga.Ogedegbe@nyumc.org [New York University School of Medicine, Clinical and Translational Science Institute, 227 E30th St, 8th Floor, New York, NY 10016 (United States)

    2014-07-15

    Objective: To compare performance of single-injection blood pool agent (gadofosveset trisodium, BPA) against dual-injection extracellular contrast (gadopentetate dimeglumine, ECA) for MRA/MRV in assessment of suspected vascular TOS. Materials and methods: Thirty-one patients referred for vascular TOS evaluation were assessed with BPA (n = 18) or ECA (n = 13) MRA/MRV in arm abduction and adduction. Images were retrospectively assessed for: image quality (1 = non-diagnostic, 5 = excellent), vessel contrast (1 = same signal as muscle, 4 = much brighter than muscle) and vascular pathology by two independent readers, with a separate experienced reader providing reference assessment of vascular pathology. Results: Median image quality was diagnostic or better (score ≥3) for ECA and BPA at all time points, with BPA image quality superior at abduction late (BPA 4.5, ECA 4, p = 0.042) and ECA image quality superior at adduction-early (BPA 4.5; ECA 4.0, p = 0.018). High qualitative vessel contrast (mean score ≥3) was observed at all time points with both BPA and ECA, with superior BPA vessel contrast at abduction-late (BPA 3.97 ± 0.12; ECA 3.73 ± 0.26, p = 0.007) and ECA at adduction-early (BPA 3.42 ± 0.52; ECA 3.96 ± 0.14, p < 0.001). Readers readily identified arterial and venous pathology with BPA, similar to ECA examinations. Conclusion: Single-injection BPA MRA/MRV for TOS evaluation demonstrated diagnostic image quality and high vessel contrast, similar to dual-injection ECA imaging, enabling identification of fixed and functional arterial and venous pathology.

  4. Preparation and Evaluation of Multiple Nanoemulsions Containing Gadolinium (III) Chelate as a Potential Magnetic Resonance Imaging (MRI) Contrast Agent.

    Science.gov (United States)

    Sigward, Estelle; Corvis, Yohann; Doan, Bich-Thuy; Kindsiko, Kadri; Seguin, Johanne; Scherman, Daniel; Brossard, Denis; Mignet, Nathalie; Espeau, Philippe; Crauste-Manciet, Sylvie

    2015-09-01

    The objective was to develop, characterize and assess the potentiality of W1/O/W2 self-emulsifying multiple nanoemulsions to enhance signal/noise ratio for Magnetic Resonance Imaging (MRI). For this purpose, a new formulation, was designed for encapsulation efficiency and stability. Various methods were used to characterize encapsulation efficiency ,in particular calorimetric methods (Differential Scanning Calorimetry (DSC), thermogravimetry analysis) and ultrafiltration. MRI in vitro relaxivities were assessed on loaded DTPA-Gd multiple nanoemulsions. Characterization of the formulation, in particular of encapsulation efficiency was a challenge due to interactions found with ultrafiltration method. Thanks to the specifically developed DSC protocol, we were able to confirm the formation of multiple nanoemulsions, differentiate loaded from unloaded nanoemulsions and measure the encapsulation efficiency which was found to be quite high with a 68% of drug loaded. Relaxivity studies showed that the self-emulsifying W/O/W nanoemulsions were positive contrast agents, exhibiting higher relaxivities than those of the DTPA-Gd solution taken as a reference. New self-emulsifying multiple nanoemulsions that were able to load satisfactory amounts of contrasting agent were successfully developed as potential MRI contrasting agents. A specific DSC protocol was needed to be developed to characterize these complex systems as it would be useful to develop these self-formation formulations.

  5. Radio response of human lymphocytes pretreated with boron and gadoliniums assessed by the, comet assay

    International Nuclear Information System (INIS)

    Kim, J. K.; Park, T. W.; Cebulska-Wasiewska, A.; Nili, M.

    2009-01-01

    Boron and gadolinium are among the nuclides that hold a unique property of being a neutron capture therapy agent. Neutron beams have often a considerable portion of gamma rays with fast neutrons. Gamma rays, as beam contaminants, can cause considerable damage to normal tissues even if such tissues do contain high boron concentrations. Materials and Methods: The modification of radio response in human lymphocytes pretreated with boron or gadolinium compound was studied by assessing the DNA damage using single cell gel electrophoresis, the comet assay. The lymphocytes from the human peripheral blood were irradiated with 0, 1, 2 and 4 Gy of gamma rays from a 60 Co isotopic source with or without pretreatment of boron or gadolinium compound for 10 minutes at 4 d egree C . Post-irradiation procedures included slide preparation, cell-lysing, unwinding and electrophoresis, neutralization, staining, and analytic steps, gel electrophoresis. Results: The results indicate that pretreatment with boron compound (50 n M or 250 n M of 10 B) is effective in reducing the radiosensitivity of the lymphocyte DNA. Conversely, pretreatment with gadolinium compound (50 n M) led to a dose-dependent increase in the radiosensitivity, most prominently with a dose of 4 Gy (P<0.001). Furthermore, when the lymphocytes were pretreated with a Combined mixture (1:1) of boron (250 n M) and gadolinium (50 n M) compounds, the reduced radiosensitivity was also observed.

  6. Glyphosate, a chelating agent-relevant for ecological risk assessment?

    Science.gov (United States)

    Mertens, Martha; Höss, Sebastian; Neumann, Günter; Afzal, Joshua; Reichenbecher, Wolfram

    2018-02-01

    Glyphosate-based herbicides (GBHs), consisting of glyphosate and formulants, are the most frequently applied herbicides worldwide. The declared active ingredient glyphosate does not only inhibit the EPSPS but is also a chelating agent that binds macro- and micronutrients, essential for many plant processes and pathogen resistance. GBH treatment may thus impede uptake and availability of macro- and micronutrients in plants. The present study investigated whether this characteristic of glyphosate could contribute to adverse effects of GBH application in the environment and to human health. According to the results, it has not been fully elucidated whether the chelating activity of glyphosate contributes to the toxic effects on plants and potentially on plant-microorganism interactions, e.g., nitrogen fixation of leguminous plants. It is also still open whether the chelating property of glyphosate is involved in the toxic effects on organisms other than plants, described in many papers. By changing the availability of essential as well as toxic metals that are bound to soil particles, the herbicide might also impact soil life, although the occurrence of natural chelators with considerably higher chelating potentials makes an additional impact of glyphosate for most metals less likely. Further research should elucidate the role of glyphosate (and GBH) as a chelator, in particular, as this is a non-specific property potentially affecting many organisms and processes. In the process of reevaluation of glyphosate its chelating activity has hardly been discussed.

  7. Assessment of toxicity on chelating agent DTPA (diethylenetriaminepentaacetic acid)

    International Nuclear Information System (INIS)

    Fukuda, Satoshi

    1989-01-01

    DTPA (diethylenetriaminepentaacetic acid) is a very important chelating agent to decorporate the radionuclides such as plutonium and americium from human body. However, before DTPA will be administered to humans, the toxicity should be clarified. This report described the summary on data of DTPA toxicities obtained from animal experiments and assessment on the safety for humans, based on the results that compared their data among animal species. In short, Ca-DTPA is less toxic than Zn-DTPA when it is injected intravenously, while Zn-DTPA is less toxic than Ca-DTPA when it is administered orally. Both DTPAs acted on the serum calcium metabolism and induced the functional damages of cardiovascular system. Particularly, it is stressed that Zn-DTPA by intravenous injection occurred the heart failure, increases of blood pressure and pulse with hypocalcemia in even normal rats and beagle dogs. Other side effects by both DTPAs were also observed in the intestine, liver, kidney and bone. It is estimated that there are almost no species differences on DTPA toxicity between animals and humans. As a result, it is concluded that DTPA should be used very carefully for humans, with reference to the results obtained from animal experiments. (author) 61 refs

  8. Assessment of toxicity on chelating agent DTPA (diethylenetriaminepentaacetic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Satoshi (National Inst. of Radiological Sciences, Chiba (Japan))

    1989-09-01

    DTPA (diethylenetriaminepentaacetic acid) is a very important chelating agent to decorporate the radionuclides such as plutonium and americium from human body. However, before DTPA will be administered to humans, the toxicity should be clarified. This report described the summary on data of DTPA toxicities obtained from animal experiments and assessment on the safety for humans, based on the results that compared their data among animal species. In short, Ca-DTPA is less toxic than Zn-DTPA when it is injected intravenously, while Zn-DTPA is less toxic than Ca-DTPA when it is administered orally. Both DTPAs acted on the serum calcium metabolism and induced the functional damages of cardiovascular system. Particularly, it is stressed that Zn-DTPA by intravenous injection occurred the heart failure, increases of blood pressure and pulse with hypocalcemia in even normal rats and beagle dogs. Other side effects by both DTPAs were also observed in the intestine, liver, kidney and bone. It is estimated that there are almost no species differences on DTPA toxicity between animals and humans. As a result, it is concluded that DTPA should be used very carefully for humans, with reference to the results obtained from animal experiments. (author) 61 refs.

  9. Critical Questions Regarding Gadolinium Deposition in the Brain and Body After Injections of the Gadolinium-Based Contrast Agents, Safety, and Clinical Recommendations in Consideration of the EMA's Pharmacovigilance and Risk Assessment Committee Recommendation for Suspension of the Marketing Authorizations for 4 Linear Agents.

    Science.gov (United States)

    Runge, Val M

    2017-06-01

    For magnetic resonance, the established class of intravenous contrast media is the gadolinium-based contrast agents. In the 3 decades since initial approval, these have proven in general to be very safe for human administration. However, in 2006, a devastating late adverse reaction to administration of the less stable gadolinium-based contrast agents was identified, nephrogenic systemic fibrosis. The result of actions taken by the European Medicines Agency and the US Food and Drug Administration, stratifying the agents by risk and contraindicating specific agents in severe renal dysfunction, has led to no new cases being identified in North America or Europe. Subsequently, in 2014, long-term deposition in the brain of gadolinium was first shown, after administration of 2 nonionic linear chelates, gadodiamide, and gadopentetate dimeglumine. This has led to an intense focus on the question of in vivo distribution, possible dechelation, and subsequent deposition of gadolinium, together with substantial clarification of the phenomenon as well as stratification of the agents on this basis. This review focuses on 8 critical questions regarding gadolinium deposition in the brain and body, with the answers and discussion therein important for future regulatory decisions and clinical practice. It is now clear that dechelation of gadolinium occurs in vivo with the linear agents and is responsible for this phenomenon, with key experts in the field recommending, except where there is no suitable alternative, a shift in clinical practice from the linear to macrocyclic agents. In addition, on March 10, 2017, the Pharmacovigilance and Risk Assessment Committee of the European Medicines Agency recommended suspension of the marketing authorization for 4 linear gadolinium contrast agents-specifically Omniscan, Optimark, Magnevist, and MultiHance (gadodiamide, gadoversetamide, gadopentetate dimeglumine, and gadobenate dimeglumine)-for intravenous injection. Cited in the report was

  10. Gadolinium Contrast Agent is of Limited Value for Magnetic Resonance Imaging Assessment of Synovial Hypertrophy in Hemophiliacs

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, B.; Berntorp, E.; Pettersson, H.; Wirestam, R.; Jonsson, K.; Staahlberg, F.; Ljung, R. [Dept. of Radiology, Univ Hospital of Lund, Lund (Sweden)

    2007-07-15

    Purpose: To examine the influence of different doses of gadolinium contrast agent on synovial enhancement, to compare magnetic resonance imaging (MRI) findings of synovial hypertrophy and radiographic joint changes in hemophiliacs, and to investigate the value of gadolinium in MRI assessment of synovial hypertrophy in hemophiliacs using dynamic MRI and MRI scoring. Material and Methods: Twenty-one hemophiliacs on prophylactic factor treatment without recent bleeds were subjected to radiography and gadolinium contrast-enhanced dynamic and static MRI of the knee using a standard dose of 0.1 mmol/kg b.w. gadoteridol. In 17 of the patients, the MRI procedure was repeated after a triple dose of gadoteridol. Results: MRI findings of synovial hypertrophy were significantly correlated with Pettersson radiographic scores. In 19 of the 21 MRI investigated joints, administration of contrast agent did not alter the result of the evaluation of synovial hypertrophy. Conclusion: The optimal time interval for volume assessment of synovial hypertrophy after injection of gadolinium contrast agent is dose dependent. Hemophiliacs without recent bleeds have minor to abundant synovial hypertrophy in joints with pronounced radiographic changes. Dynamic MRI is not useful for evaluating hemophilic arthropathy, and gadolinium contrast agent is not routinely indicated for MRI scoring of joints in hemophiliacs.

  11. Gadolinium Contrast Agent is of Limited Value for Magnetic Resonance Imaging Assessment of Synovial Hypertrophy in Hemophiliacs

    International Nuclear Information System (INIS)

    Lundin, B.; Berntorp, E.; Pettersson, H.; Wirestam, R.; Jonsson, K.; Staahlberg, F.; Ljung, R.

    2007-01-01

    Purpose: To examine the influence of different doses of gadolinium contrast agent on synovial enhancement, to compare magnetic resonance imaging (MRI) findings of synovial hypertrophy and radiographic joint changes in hemophiliacs, and to investigate the value of gadolinium in MRI assessment of synovial hypertrophy in hemophiliacs using dynamic MRI and MRI scoring. Material and Methods: Twenty-one hemophiliacs on prophylactic factor treatment without recent bleeds were subjected to radiography and gadolinium contrast-enhanced dynamic and static MRI of the knee using a standard dose of 0.1 mmol/kg b.w. gadoteridol. In 17 of the patients, the MRI procedure was repeated after a triple dose of gadoteridol. Results: MRI findings of synovial hypertrophy were significantly correlated with Pettersson radiographic scores. In 19 of the 21 MRI investigated joints, administration of contrast agent did not alter the result of the evaluation of synovial hypertrophy. Conclusion: The optimal time interval for volume assessment of synovial hypertrophy after injection of gadolinium contrast agent is dose dependent. Hemophiliacs without recent bleeds have minor to abundant synovial hypertrophy in joints with pronounced radiographic changes. Dynamic MRI is not useful for evaluating hemophilic arthropathy, and gadolinium contrast agent is not routinely indicated for MRI scoring of joints in hemophiliacs

  12. Dual modal ultra-bright nanodots with aggregation-induced emission and gadolinium-chelation for vascular integrity and leakage detection.

    Science.gov (United States)

    Feng, Guangxue; Li, Jackson Liang Yao; Claser, Carla; Balachander, Akhila; Tan, Yingrou; Goh, Chi Ching; Kwok, Immanuel Weng Han; Rénia, Laurent; Tang, Ben Zhong; Ng, Lai Guan; Liu, Bin

    2018-01-01

    The study of blood brain barrier (BBB) functions is important for neurological disorder research. However, the lack of suitable tools and methods has hampered the progress of this field. Herein, we present a hybrid nanodot strategy, termed AIE-Gd dots, comprising of a fluorogen with aggregation-induced emission (AIE) characteristics as the core to provide bright and stable fluorescence for optical imaging, and gadolinium (Gd) for accurate quantification of vascular leakage via inductively-coupled plasma mass spectrometry (ICP-MS). In this report, we demonstrate that AIE-Gd dots enable direct visualization of brain vascular networks under resting condition, and that they form localized punctate aggregates and accumulate in the brain tissue during experimental cerebral malaria, indicative of hemorrhage and BBB malfunction. With its superior detection sensitivity and multimodality, we hereby propose that AIE-Gd dots can serve as a better alternative to Evans blue for visualization and quantification of changes in brain barrier functions. Copyright © 2017. Published by Elsevier Ltd.

  13. Contrast-enhanced magnetic resonance angiography: first-pass arterial enhancement as a function of gadolinium-chelate concentration, and the saline chaser volume and injection rate.

    Science.gov (United States)

    Husarik, Daniela B; Bashir, Mustafa R; Weber, Paul W; Nichols, Eli B; Howle, Laurens E; Merkle, Elmar M; Nelson, Rendon C

    2012-02-01

    To evaluate the effect of the contrast medium (CM) concentration and the saline chaser volume and injection rate on first-pass aortic enhancement characteristics in contrast-enhanced magnetic resonance angiography using a physiologic flow phantom. Imaging was performed on a 3.0-T magnetic resonance system (MAGNETOM Trio, Siemens Healthcare Solutions, Inc, Erlangen, Germany) using a 2-dimensional fast low angle shot T1-weighted sequence (repetition time, 500 milliseconds; echo time, 1.23 milliseconds; flip angle, 8 degrees; 1 frame/s × 60 seconds). The following CM concentrations injected at 2 mL/s were used with 3 different contrast agents (gadolinium [Gd]-BOPTA, Gd-HP-DO3A, Gd-DTPA): 20 mL of undiluted CM (100%) and 80%, 40%, 20%, 10%, 5%, and 2.5% of the full amount, all diluted in saline to a volume of 20 mL to ensure equal bolus volume. The CM was followed by saline chasers of 20 to 60 mL injected at 2 mL/s and 6 mL/s. Aortic signal intensity (SI) was measured, and normalized SI versus time (SI/Tn) curves were generated. The maximal SI (SI(max)), bolus length, and areas under the SI/Tn curve were calculated. Decreasing the CM concentration from 100% to 40% resulted in a decrease of SI(max) to 86.1% (mean). Further decreasing the CM concentration to 2.5% decreased SI(max) to 5.1% (mean). Altering the saline chaser volume had no significant effect on SI(max). Increasing the saline chaser injection rate had little effect (mean increase, 2.2%) on SI(max) when using ≥40% of CM. There was a larger effect (mean increase, 19.6%) when ≤20% of CM were used. Bolus time length was significantly shorter (P < 0.001), and area under the SI/T(n) curve was significantly smaller (P < 0.01) for the CM protocols followed by a saline chaser injected at 6 mL/s compared with a saline chaser injected at 2 mL/s. With 40% of CM and a fast saline chaser, SImax close to that with undiluted CM can be achieved. An increased saline chaser injection rate has a more pronounced effect on

  14. Design and Methodology of the Trial to Assess Chelation Therapy (TACT)

    Science.gov (United States)

    Lamas, Gervasio A.; Goertz, Christine; Boineau, Robin; Mark, Daniel B.; Rozema, Theodore; Nahin, Richard L.; Drisko, Jeanne A.; Lee, Kerry L.

    2011-01-01

    The Trial to Assess Chelation Therapy (TACT) is an NIH-sponsored, randomized, double blind, placebo-controlled, 2×2 factorial clinical trial testing the benefits and risks of 40 infusions of a multi-component Na2EDTA-chelation solution compared with placebo, and of an oral, high-dose multivitamin and mineral supplement. TACT has randomized and will follow 1708 patients for an average of approximately 4 years. The primary endpoint is a composite of all cause mortality, myocardial infarction, stroke, coronary revascularization, and hospitalization for angina. A 900 patient substudy will examine quality of life outcomes. The trial is designed to have >85% power to detect a 25% relative reduction in the primary endpoint for each treatment factor. Enrollment began in September 2003 and completed in October 2010. PMID:22172430

  15. Assessment of the Efficacy of Chelate-Assisted Phytoextraction of Lead by Coffeeweed (Sesbania exaltata Raf.

    Directory of Open Access Journals (Sweden)

    Gloria Miller

    2008-12-01

    Full Text Available Lead (Pb, depending upon the reactant surface, pH, redox potential and other factors can bind tightly to the soil with a retention time of many centuries. Soil-metal interactions by sorption, precipitation and complexation processes, and differences between plant species in metal uptake efficiency, transport, and susceptibility make a general prediction of soil metal bioavailability and risks of plant metal toxicity difficult. Moreover, the tight binding characteristic of Pb to soils and plant materials make a significant portion of Pb unavailable for uptake by plants. This experiment was conducted to determine whether the addition of ethylenediaminetetraacetic acid (EDTA, ethylene glycol tetraacetic acid (EGTA, or acetic acid (HAc can enhance the phytoextraction of Pb by making the Pb soluble and more bioavailable for uptake by coffeeweed (Sesbania exaltata Raf.. Also we wanted to assess the efficacy of chelates in facilitating translocation of the metal into the above-ground biomass of this plant. To test the effect of chelates on Pb solubility, 2 g of Pb-spiked soil (1000 mg Pb/kg dry soil were added to each 15 mL centrifuge tube. Chelates (EDTA, EGTA, HAc in a 1:1 ratio with the metal, or distilled deionized water were then added. Samples were shaken on a platform shaker then centrifuged at the end of several time periods. Supernatants were filtered with a 0.45 μm filter and quantified by inductively coupled plasma-optical emission spectrometry (ICP-OES to determine soluble Pb concentrations. Results revealed that EDTA was the most effective in bringing Pb into solution, and that maximum solubility was reached 6 days after chelate amendment. Additionally, a greenhouse experiment was conducted by planting Sesbania seeds in plastic tubes containing top soil and peat (2:1, v:v spiked with various levels (0, 1000, 2000 mg Pb/kg dry soil of lead nitrate. At six weeks after emergence, aqueous solutions of EDTA and/or HAc (in a 1:1 ratio

  16. Correlation between late gadolinium enhancement and diastolic function in hypertrophic cardiomyopathy assessed by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Motoyasu, Munenobu; Kurita, Tairo; Onishi, Katsuya

    2008-01-01

    Diastolic dysfunction is common in patients with overt hypertrophic cardiomyopathy (HCM). Steady-state cine magnetic resonance imaging (MRI) enables measurement of the diastolic function of the left ventricle (LV), and late gadolinium enhanced MRI can delineate the presence and extent of fibrosis in HCM. The purpose of this study was to determine the relationship between the extent of myocardial fibrosis demonstrated by late gadolinium-enhanced MRI and diastolic dysfunction. Seventeen patients (13 men, mean age 57.7±9.8 years) with HCM were studied. The severity index of late gadolinium enhancement was determined by scoring the extent of enhanced tissue in 30 myocardial segments. The peak filling rate (PFR), LV ejection fraction and LV mass were determined by cine MRI. Contrast-enhanced MRI demonstrated late gadolinium enhancement in 97 of 510 segments (19%) and 13 of the 17 patients (77%). The severity index of late gadolinium enhancement demonstrated a significant negative correlation with PFR (r=-0.86, p<0.01) and with the LV ejection fraction (r=-0.59, p<0.05). No significant correlation was observed between the severity index of late gadolinium enhancement and LV mass (r=0.23, p=0.30). The extent of myocardial fibrosis revealed by late gadolinium-enhanced MRI has a strong relationship to diastolic dysfunction in patients with HCM. (author)

  17. Serial quantitative MR assessment of optic neuritis in a case of neuromyelitis optica, using gadolinium-'enhanced' STIR imaging

    International Nuclear Information System (INIS)

    Barkhof, F.; Scheltens, P.; Valk, J.; Waalewijn, C.; Uitdehaag, B.M.J.; Polman, C.H.

    1991-01-01

    A patient is presented with neuromyelitis optica. MR imaging, using a short inversion time inversion recovery (STIR) technique, clearly depicted the lesion in the left optic nerve. Subsequent serial STIR imaging, with and without Gadolinium-DTPA, allowed quantitative assessment of changes parallel to improved optic nerve function. STIR imaging is a sensitive technique to demonstrate optic nerve lesions, and enables quantitative assessment to be made of the effect of (steroid) medication. (orig.)

  18. Assessment of a gel-type chelating preparation containing 1-hydroxyethylidene-1, 1-bisphosphonate.

    Science.gov (United States)

    Girard, S; Paqué, F; Badertscher, M; Sener, B; Zehnder, M

    2005-11-01

    To test an aqueous gel containing 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) regarding its interactions with sodium hypochlorite, its calcium binding capacity, and its potential in preventing the formation of a smear layer when used in conjunction with rotary root canal preparation. The experimental aqueous gel consisted of (w/v) 2% alginate, 3% aerosil, 10% Tween 80 and 18% HEBP. Interactions of gel components with hypochlorite were assessed using iodometric titration and monochromatic ultraviolet spectrometry. Two commercial paste-type chelators containing ethylenediaminetetraacetic acid (EDTA) and peroxide (RC-Prep and Glyde) served as controls. Calcium-binding capacities were measured in mixtures with a Ca2+ standard solution buffered at pH 10 using a calcium-selective measuring chain. Finally, root canals of 16 extracted single-rooted premolars per group were instrumented using ProFile instruments dipped in the experimental gel, RC-Prep, or nothing. Additionally, canals were rinsed with 10 mL of a 1% NaOCl solution during/after preparation. Smear scores in instrumented teeth were monitored using scanning electron microscopy. None of the experimental gel components showed short-term interactions with hypochlorite, whilst EDTA, peroxide, RC-Prep and Glyde immediately reduced the hypochlorite in solution. The experimental gel chelated 30 mg Ca2+ g-1, compared with 16 mg Ca2+ g-1 and 11 mg Ca2+ g-1 chelated by RC-Prep and Glyde respectively. Smear scores obtained with the experimental gel were significantly (P<0.05) lower than with RC-Prep in coronal and middle root thirds, whilst no differences were observed in apical root thirds. Under the conditions of this study, an HEBP gel appeared advantageous over currently available products.

  19. Assessment of the body burden of chelatable lead: a model and its application to lead workers

    Energy Technology Data Exchange (ETDEWEB)

    Araki, S.; Ushio, K.

    1982-05-01

    A hypothetical model was introduced to estimate the body burden of chelatable lead from the mobilisation yield of lead by calcium disodium ethylenediamine tetra-acetate. It was estimated that, on average, 14 and 19% of the body burden was mobilized into the urine during the 24 hours after an injection of 53.4 mumol and 107 mumol CaEDTA per kg bodyweight, respectively. The body burden of chelatable lead ranged from 4 mumol to 120 mumol in lead workers with blood lead concentrations of 0.3-2.9 mumol/kg. There were linear relationships between blood lead concentrations and body burden of chelatable lead on a log scale.

  20. Phytoextraction of heavy metals from contaminated soil by co-cropping with chelator application and assessment of associated leaching risk.

    Science.gov (United States)

    Wei, Z B; Guo, X F; Wu, Q T; Long, X X; Penn, C J

    2011-08-01

    Phytoextraction using hyperaccumulating plants is generally time-consuming and requires the cessation of agriculture. We coupled chelators and a co-cropping system to enhance phytoextraction rates, while allowing for agricultural production. An experiment on I m3 lysimeter beds was conducted with a co-cropping system consisting of the hyperaccumulator Sedum alfredii and low-accumulating corn (Zea Mays, cv. Huidan-4), with addition ofa mixture of chelators (MC), to assess the efficiency of chelator enhanced co-crop phytoextraction and the leaching risk caused by the chelator. The results showed that the addition of MC promoted the growth of S. alfredii in the first crop (spring-summer season) and significantly increased the metal phytoextraction. The DTPA-extractable and total metal concentrations in the topsoil were also reduced more significantly with the addition of MC compared with the control treatments. However, mono-cropped S. alfredii without MC was more suitable for maximizing S. alfredii growth and therefore phytoextraction of Zn and Cd during the autumn-winter seasons. No adverse impact to groundwater due to MC application was observed during the experiments with three crops and three MC applications. But elevated total Cd and Pb concentrations among subsoils compared to the initial subsoil concentrations were found for the co-crop + MC treatment after the third crop.

  1. Assessment of the body burden of chelatable lead: a model and its application to lead workers.

    Science.gov (United States)

    Araki, S; Ushio, K

    1982-01-01

    A hypothetical model was introduced to estimate the body burden of chelatable lead from the mobilisation yield of lead by calcium disodium ethylenediamine tetra-acetate (CaEDTA). It was estimated that, on average, 14 and 19% of the body burden was mobilised into the urine during the 24 hours after an injection of 53.4 mumol (20 mg) and 107 mumol (40 mg) CaEDTA per kg bodyweight, respectively. The body burden of chelatable lead ranged from 4 mumol (0.8 mg) to 120 mumol (24.9 mg) (mean 37 mumol (7.7 mg) in lead workers with blood lead concentrations of 0.3-2.9 mumol/kg (6-60 microgram/100 g) (mean 1.4 mumol/kg (29 microgram/100 g)). There were linear relationships between blood lead concentrations and body burden of chelatable lead on a log scale. PMID:6802167

  2. Assessment of the body burden of chelatable lead: a model and its application to lead workers.

    OpenAIRE

    Araki, S; Ushio, K

    1982-01-01

    A hypothetical model was introduced to estimate the body burden of chelatable lead from the mobilisation yield of lead by calcium disodium ethylenediamine tetra-acetate (CaEDTA). It was estimated that, on average, 14 and 19% of the body burden was mobilised into the urine during the 24 hours after an injection of 53.4 mumol (20 mg) and 107 mumol (40 mg) CaEDTA per kg bodyweight, respectively. The body burden of chelatable lead ranged from 4 mumol (0.8 mg) to 120 mumol (24.9 mg) (mean 37 mumol...

  3. Role of MRI T2-DRIVE in the assessment of pituitary stalk abnormalities without gadolinium in pituitary diseases.

    Science.gov (United States)

    Godano, Elisabetta; Morana, Giovanni; Di Iorgi, Natascia; Pistorio, Angela; Allegri, Anna Elsa Maria; Napoli, Flavia; Gastaldi, Roberto; Calcagno, Annalisa; Patti, Giuseppa; Gallizia, Annalisa; Notarnicola, Sara; Giaccardi, Marta; Noli, Serena; Severino, Mariasavina; Tortora, Domenico; Rossi, Andrea; Maghnie, Mohamad

    2018-06-01

    To investigate the role of T2-DRIVE MRI sequence in the accurate measurement of pituitary stalk (PS) size and the identification of PS abnormalities in patients with hypothalamic-pituitary disorders without the use of gadolinium. This was a retrospective study conducted on 242 patients who underwent MRI due to pituitary dysfunction between 2006 and 2015. Among 135 eligible patients, 102 showed eutopic posterior pituitary (PP) gland and 33 showed 'ectopic' PP (EPP). Two readers independently measured the size of PS in patients with eutopic PP at the proximal, midpoint and distal levels on pre- and post-contrast T1-weighted as well as T2-DRIVE images; PS visibility was assessed on pre-contrast T1 and T2-DRIVE sequences in those with EPP. The length, height, width and volume of the anterior pituitary (AP), PP height and length and PP area were analyzed. Significant agreement between the two readers was obtained for T2-DRIVE PS measurements in patients with 'eutopic' PP; a significant difference was demonstrated between the intraclass correlation coefficient calculated on the T2-DRIVE and the T1-pre- and post-contrast sequences. The percentage of PS identified by T2-DRIVE in EPP patients was 72.7% compared to 30.3% of T1 pre-contrast sequences. A significant association was found between the visibility of PS on T2-DRIVE and the height of AP. T2-DRIVE sequence is extremely precise and reliable for the evaluation of PS size and the recognition of PS abnormalities; the use of gadolinium-based contrast media does not add significant information and may thus be avoided. © 2018 European Society of Endocrinology.

  4. Serial quantitative MR assessment of optic neuritis in a case of neuromyelitis optica, using gadolinium-'enhanced' STIR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barkhof, F.; Scheltens, P.; Valk, J. (Vrije Univ., Amsterdam (Netherlands). Dept. of Diagnostic Radiology); Waalewijn, C.; Uitdehaag, B.M.J.; Polman, C.H. (Vrije Univ., Amsterdam (Netherlands). Dept. of Neurology)

    1991-02-01

    A patient is presented with neuromyelitis optica. MR imaging, using a short inversion time inversion recovery (STIR) technique, clearly depicted the lesion in the left optic nerve. Subsequent serial STIR imaging, with and without Gadolinium-DTPA, allowed quantitative assessment of changes parallel to improved optic nerve function. STIR imaging is a sensitive technique to demonstrate optic nerve lesions, and enables quantitative assessment to be made of the effect of (steroid) medication. (orig.).

  5. Role of chelates in magnetic resonance imaging studies

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2009-01-01

    Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

  6. Molecular Docking Assessment of Efficacy of Different Clinically Used Arsenic Chelator Drugs

    OpenAIRE

    Durjoy Majumder; Sayan Mukherjee

    2013-01-01

    Arsenic contamination of ground water has become a global problem affecting specially, south-east Asian countries like Bangladesh and eastern parts of India. It also affects South America and some parts of the US. Different organs of the physiological system are affected due to contamination of inorganic arsenic in water. Animal studies with different chelators are not very conclusive as far as the multi/differential organ effect(s) of arsenic is concerned. Our docking study establishes the m...

  7. Satisfaction and adherence in patients with iron overload receiving iron chelation therapy as assessed by a newly developed patient instrument.

    Science.gov (United States)

    Rofail, Diana; Abetz, Linda; Viala, Muriel; Gait, Claire; Baladi, Jean-Francois; Payne, Krista

    2009-01-01

    This study assesses satisfaction with iron chelation therapy (ICT) based on a reliable and valid instrument, and explores the relationship between satisfaction and adherence to ICT. Patients in the USA and UK completed a new "Satisfaction with ICT" (SICT) instrument consisting of 28 items, three pertaining to adherence. Simple and multivariate regression analyses assessed the relationship between satisfaction with different aspects of ICT and adherence. First assessments of the SICT instrument indicate its validity and reliability. Recommended thresholds for internal consistency, convergent validity, discriminant validity, and floor and ceiling effects were met. A number of variables were identified in the simple linear regression analyses as significant predictors of "never thinking about stopping ICT," a proxy for adherence. These significant variables were entered into the multivariate model to assess the combined factor effects, explaining 42% of the total variance of "never thinking about stopping ICT." A significant and positive relationship was demonstrated between "never thinking about stopping ICT" and age (P = 0.04), Perceived Effectiveness of ICT (P = 0.003), low Burden of ICT (P = 0.002), and low Side Effects of ICT (P = 0.01). The SICT is a reliable and valid instrument which will be useful in ICT clinical trials. Furthermore, the administration of ICT by slow subcutaneous infusion negatively impacts on satisfaction with ICT which was shown to be a determinant of adherence. This points to the need for new more convenient and less burdensome oral iron chelators to increase adherence, and ultimately to improve patient outcomes.

  8. Effects of motexafin gadolinium on DNA damage and X-ray-induced DNA damage repair, as assessed by the Comet assay

    International Nuclear Information System (INIS)

    Donnelly, Erling T.; Liu Yanfeng; Paul, Tracy K.; Rockwell, Sara

    2005-01-01

    Purpose: To investigate the effects of motexafin gadolinium (MGd) on the levels of reactive oxygen species (ROS), glutathione (GSH), and DNA damage in EMT6 mouse mammary carcinoma cells. The ability of MGd to alter radiosensitivity and to inhibit DNA damage repair after X-ray irradiation was also evaluated. Methods and Materials: Reactive oxygen species and GSH levels were assessed by 2,7-dichlorofluorescein fluorescence flow cytometry and the Tietze method, respectively. Cellular radiosensitivity was assessed by clonogenic assays. Deoxyribonucleic acid damage and DNA damage repair were assessed in plateau-phase EMT6 cells by the Comet assay and clonogenic assays. Results: Cells treated with 100 μmol/L MGd plus equimolar ascorbic acid (AA) had significantly increased levels of ROS and a 58.9% ± 3.4% decrease in GSH levels, relative to controls. Motexafin gadolinium plus AA treatment increased the hypoxic, but not the aerobic, radiosensitivity of EMT6 cells. There were increased levels of single-strand breaks in cells treated with 100 μmol/L MGd plus equimolar AA, as evidenced by changes in the alkaline tail moment (MGd + AA, 6 h: 14.7 ± 1.8; control: 2.8 ± 0.9). The level of single-strand breaks was dependent on the length of treatment. Motexafin gadolinium plus AA did not increase double-strand breaks. The repair of single-strand breaks at 2 h, but not at 4 h and 6 h, after irradiation was altered significantly in cells treated with MGd plus AA (MGd + AA, 2 h: 15.8 ± 3.4; control: 5.8 ± 0.6). Motexafin gadolinium did not alter the repair of double-strand breaks at any time after irradiation with 10 Gy. Conclusions: Motexafin gadolinium plus AA generated ROS, which in turn altered GSH homeostasis and induced DNA strand breaks. The MGd plus AA-mediated alteration of GSH levels increased the hypoxic, but not aerobic, radiosensitivity of EMT6 cells. Motexafin gadolinium altered the kinetics of single-strand break repair soon after irradiation but did not

  9. Extracellular gadolinium contrast agents: Differences in stability

    International Nuclear Information System (INIS)

    Morcos, S.K.

    2008-01-01

    Extracellular gadolinium contrast agents (Gd-CA) are either linear or macrocyclic chelates available as ionic or non-ionic preparations. The molecular structure whether cyclic or linear and ionicity determines the stability of Gd-CA. Linear chelates are flexible open chains which do not offer a strong binding to Gd 3+ . In contrast, the macrocyclic chelates offer a strong binding to Gd 3+ by the virtue of being preorganized rigid rings of almost optimal size to cage the gadolinium atom. Non-ionic preparations are also less stable in comparison to the ionic ones as the binding between Gd 3+ with the negatively charged carboxyl groups is stronger in comparison to that with amides or alcohol in the non-ionic preparations. According to stability constants and kinetic measurements, the most stable Gd-CM is the ionic-macrocyclic chelate Gd-DOTA and the least stable agents are the non-ionic linear chelates gadodiamide and gadoversetamide. In vivo data confirmed the low stability of non-ionic linear chelates but no significant difference was observed amongst the macrocyclic agents whether ionic (Gd-DOTA) or non-ionic such as Gd-HP-DO3A and Gd-BT-DO3A. The stability of Gd-CA seems to be an important factor in the pathogenesis of the serious complication of nephrogenic systemic fibrosis. Gd-CA of low stability are likely to undergo transmetallation and release free Gd ions that deposit in tissue and attract circulating fibrocytes to initiate the process of fibrosis. No cases of NSF have been observed so far after the exclusive use of the stable macrocyclic Gd-CA

  10. Fully automatic segmentation of left atrium and pulmonary veins in late gadolinium-enhanced MRI: Towards objective atrial scar assessment.

    Science.gov (United States)

    Tao, Qian; Ipek, Esra Gucuk; Shahzad, Rahil; Berendsen, Floris F; Nazarian, Saman; van der Geest, Rob J

    2016-08-01

    To realize objective atrial scar assessment, this study aimed to develop a fully automatic method to segment the left atrium (LA) and pulmonary veins (PV) from late gadolinium-enhanced (LGE) magnetic resonance imaging (MRI). The extent and distribution of atrial scar, visualized by LGE-MRI, provides important information for clinical treatment of atrial fibrillation (AF) patients. Forty-six AF patients (age 62 ± 8, 14 female) who underwent cardiac MRI prior to RF ablation were included. A contrast-enhanced MR angiography (MRA) sequence was acquired for anatomy assessment followed by an LGE sequence for LA scar assessment. A fully automatic segmentation method was proposed consisting of two stages: 1) global segmentation by multiatlas registration; and 2) local refinement by 3D level-set. These automatic segmentation results were compared with manual segmentation. The LA and PVs were automatically segmented in all subjects. Compared with manual segmentation, the method yielded a surface-to-surface distance of 1.49 ± 0.65 mm in the LA region when using both MRA and LGE, and 1.80 ± 0.93 mm when using LGE alone (P automatic and manual segmentation was comparable to the interobserver difference (P = 0.8 in LA region and P = 0.7 in PV region). We developed a fully automatic method for LA and PV segmentation from LGE-MRI, with comparable performance to a human observer. Inclusion of an MRA sequence further improves the segmentation accuracy. The method leads to automatic generation of a patient-specific model, and potentially enables objective atrial scar assessment for AF patients. J. Magn. Reson. Imaging 2016;44:346-354. © 2016 Wiley Periodicals, Inc.

  11. Quantification and Assessment of the Chemical Form of Residual Gadolinium in the Brain After Repeated Administration of Gadolinium-Based Contrast Agents

    Science.gov (United States)

    Frenzel, Thomas; Apte, Chirag; Jost, Gregor; Schöckel, Laura; Lohrke, Jessica; Pietsch, Hubertus

    2017-01-01

    Objective Multiple clinical and preclinical studies have reported a signal intensity increase and the presence of gadolinium (Gd) in the brain after repeated administration of Gd-based contrast agents (GBCAs). This bioanalytical study in rat brain tissue was initiated to investigate whether the residual Gd is present as intact GBCA or in other chemical forms by using tissue fractionation and chromatography. Materials and Methods Rats were divided randomly in 6 groups of 10 animals each. They received 10 daily injections of 2.5 mmol/kg bodyweight of 1 of 5 different GBCAs: linear GBCAs such as gadodiamide (Omniscan; GE Healthcare), gadopentetate dimeglumine (Gd-DTPA, Magnevist; Bayer), or gadobenate dimeglumine (Multihance; Bracco) and macrocyclic GBCAs such as gadobutrol (Gadovist; Bayer) and gadoterate meglumine (Gd-DOTA, Dotarem; Guerbet) or saline. On days 3 and 24 after the last injection (p.i.), 5 randomly chosen animals of each group were killed by exsanguination, and their brains were excised and divided into cerebrum, pons, and cerebellum. The brain sections were homogenized by sonication in ice-cold buffer at pH 7.4. Soluble and insoluble fractions were separated by centrifugation, and the soluble fractions were further separated by gel permeation chromatography (GPC). The Gd concentration in all tissue fractions and in the GPC eluate was measured by inductively coupled plasma–mass spectrometry. In a recovery control experiment, all GBCAs were spiked to blank brain tissue and more than 94% recovery of Gd in the tissue fractions was demonstrated. Results Only traces of the administered Gd were found in the rat brain tissue on day 3 and day 24 p.i. In the animals treated with macrocyclic GBCAs, Gd was found only in the soluble brain fraction and was present solely as low molecular weight molecules, most likely the intact GBCA. In the animals treated with linear GBCAs Gd was found to a large extent in the insoluble tissue fraction. The Gd concentration in

  12. Quantification and Assessment of the Chemical Form of Residual Gadolinium in the Brain After Repeated Administration of Gadolinium-Based Contrast Agents: Comparative Study in Rats.

    Science.gov (United States)

    Frenzel, Thomas; Apte, Chirag; Jost, Gregor; Schöckel, Laura; Lohrke, Jessica; Pietsch, Hubertus

    2017-07-01

    Multiple clinical and preclinical studies have reported a signal intensity increase and the presence of gadolinium (Gd) in the brain after repeated administration of Gd-based contrast agents (GBCAs). This bioanalytical study in rat brain tissue was initiated to investigate whether the residual Gd is present as intact GBCA or in other chemical forms by using tissue fractionation and chromatography. Rats were divided randomly in 6 groups of 10 animals each. They received 10 daily injections of 2.5 mmol/kg bodyweight of 1 of 5 different GBCAs: linear GBCAs such as gadodiamide (Omniscan; GE Healthcare), gadopentetate dimeglumine (Gd-DTPA, Magnevist; Bayer), or gadobenate dimeglumine (Multihance; Bracco) and macrocyclic GBCAs such as gadobutrol (Gadovist; Bayer) and gadoterate meglumine (Gd-DOTA, Dotarem; Guerbet) or saline. On days 3 and 24 after the last injection (p.i.), 5 randomly chosen animals of each group were killed by exsanguination, and their brains were excised and divided into cerebrum, pons, and cerebellum. The brain sections were homogenized by sonication in ice-cold buffer at pH 7.4. Soluble and insoluble fractions were separated by centrifugation, and the soluble fractions were further separated by gel permeation chromatography (GPC). The Gd concentration in all tissue fractions and in the GPC eluate was measured by inductively coupled plasma-mass spectrometry. In a recovery control experiment, all GBCAs were spiked to blank brain tissue and more than 94% recovery of Gd in the tissue fractions was demonstrated. Only traces of the administered Gd were found in the rat brain tissue on day 3 and day 24 p.i. In the animals treated with macrocyclic GBCAs, Gd was found only in the soluble brain fraction and was present solely as low molecular weight molecules, most likely the intact GBCA. In the animals treated with linear GBCAs Gd was found to a large extent in the insoluble tissue fraction. The Gd concentration in the soluble fraction was comparable to the

  13. Gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Akine, Yasuyuki; Tokita, Nobuhiko; Tokuuye, Koichi; Satoh, Michinao; Churei, Hisahiko

    1993-01-01

    Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

  14. Enrichment of gadolinium-157 and gadolinium-155 by laser method

    International Nuclear Information System (INIS)

    Xinjun, Su; Xiaowei, Zhang; Zhiquan, Li

    2008-01-01

    Laser isotope separation experiments of gadolinium by atomic vapor method have been performed. Gadolinium-157 and gadolinium-155 were selectively photoionized by means of three linearly polarized dye lasers, the excitation process of which is based on the polarization selection rules. Gramme-magnitude of enriched gadolinium was obtained and the total abundance of gadolinium-157 and gadolinium-155 was in excess of 80%, and the product rating exceeded 200 mg/h. (author)

  15. The Combined Incremental Prognostic Value of LVEF, Late Gadolinium Enhancement, and Global Circumferential Strain Assessed by CMR.

    Science.gov (United States)

    Mordi, Ify; Bezerra, Hiram; Carrick, David; Tzemos, Nikolaos

    2015-05-01

    This study aimed to assess the incremental prognostic value of global circumferential strain (GCS), as measured using cardiac magnetic resonance (CMR) tagging, in addition to baseline clinical characteristics, left ventricular ejection fraction (LVEF), and late gadolinium enhancement (LGE), in the prediction of major adverse cardiovascular events (MACE) in an unselected cohort of patients. LVEF is a powerful predictor of mortality and is used for guiding treatment decisions. It is, however, subject to limitations. The value of GCS measured by CMR tagging in patients with suspected cardiac disease has not been fully explored despite its being considered as the gold standard noninvasive method of assessment of LV deformation. We prospectively evaluated data from 539 consecutive patients referred for CMR who underwent a CMR protocol that included cine imaging, tagging, and LGE. The primary endpoint was the prevalence of MACE, defined as a composite of all-cause mortality, heart failure-related hospitalization, and aborted sudden cardiac death. MACE occurred in 62 of 539 patients (11.5%) over a mean follow-up period of 2.2 years. History of ischemic heart disease (IHD) and beta-blocker use were both significant clinical predictors of adverse outcomes. All 3 CMR parameters were significant multivariate predictors of the primary outcome when added to significant clinical predictors (LVEF, hazard ratio [HR]: 0.96 [95% confidence interval [CI]: 0.94 to 0.99; p = 0.005]; presence of LGE, HR: 2.07 [95% CI: 1.03 to 4.14; p = 0.04]; GCS, HR: 1.11 [95% CI: 1.02 to 1.21; p = 0.041]). Global chi-square increased significantly with the addition of both LGE and GCS. Both the presence of LGE and reduced GCS had independent prognostic value in the overall cohort. Patients with LVEF ≥35% but LGE present and reduced GCS had a poor outcome similar to that in those with LVEF value. This measure could provide further risk stratification, especially in patients with mild LV impairment

  16. Improved paramagnetic chelate for molecular imaging with MRI

    International Nuclear Information System (INIS)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-01-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

  17. Improved paramagnetic chelate for molecular imaging with MRI

    Science.gov (United States)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  18. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor; Villalobos Vazquez de la Parra, Luis Francisco; Hilke, Roland

    2015-01-01

    microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  19. Contrast-enhanced voiding urosonography phantom study: intravenous iodinated and gadolinium-based contrast agents may cause false-negative results in assessment of vesicoureteral reflux in children

    International Nuclear Information System (INIS)

    Veldhoen, Simon; Sauer, Alexander; Gassenmaier, Tobias; Petritsch, Bernhard; Herz, Stefan; Blanke, Philipp; Bley, Thorsten A.; Wirth, Clemens; Derlin, Thorsten

    2015-01-01

    Contrast-enhanced voiding urosonography (ce-VUS) is commonly requested simultaneously to other diagnostic imaging necessitating intravenous contrast agents. To date there is limited knowldedge about intravesical interactions between different types of contrast agents. To assess the effect of excreted intravenous iodinated and gadolinium-based contrast agents on the intravesical distribution of ultrasound contrast within contrast-enhanced voiding urosonography. Iodinated (iomeprol, iopamidol) and gadolinium-based (gadoterate meglumine) contrast agents were diluted to bladder concentration and injected into balloons filled with saline solution. CT scans were performed to assess the contrast distribution in these phantoms. Regions of interest were placed at the top and bottom side of each balloon and Hounsfield units (HU) were measured. Three other balloons were filled with saline solution and contrast media likewise. The ultrasound contrast agent sulphur hexafluoride was added and its distribution was assessed using sonography. MDCT scans showed a separation of two liquid layers in all bladder phantoms with the contrast layers located at the bottom and the saline solution at the top. Significant differences of the HU measurements at the top and bottom side were observed (P < 0.001-0.007). Following injection of ultrasound contrast agent, US showed its distribution exclusively among the saline solution. False-negative results of contrast-enhanced voiding urosonography may occur if it is performed shortly after imaging procedures requiring intravenous contrast. (orig.)

  20. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain

    International Nuclear Information System (INIS)

    Eide, Per Kristian; Ringstad, Geir

    2015-01-01

    Recently, the “glymphatic system” of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain

  1. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain.

    Science.gov (United States)

    Eide, Per Kristian; Ringstad, Geir

    2015-11-01

    Recently, the "glymphatic system" of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain.

  2. Assessment of myocardial infarction in mice by Late Gadolinium Enhancement MR imaging using an inversion recovery pulse sequence at 9.4T

    Directory of Open Access Journals (Sweden)

    Herlihy Amy H

    2008-01-01

    Full Text Available Abstract Purpose To demonstrate the feasibility of using an inversion recovery pulse sequence and to define the optimal inversion time (TI to assess myocardial infarction in mice by late gadolinium enhancement (LGE MRI at 9.4T, and to obtain the maximal contrast between the infarcted and the viable myocardium. Methods MRI was performed at 9.4T in mice, two days after induction of myocardial infarction (n = 4. For cardiovascular MR imaging, a segmented magnetization-prepared fast low angle shot (MP-FLASH sequence was used with varied TIs ranging from 40 to 420 ms following administration of gadolinium-DTPA at 0.6 mmol/kg. Contrast-to-noise (CNR and signal-to-noise ratio (SNR were measured and compared for each myocardial region of interest (ROI. Results The optimal TI, which corresponded to a minimum SNR in the normal myocardium, was 268 ms ± 27.3. The SNR in the viable myocardium was significantly different from that found in the infarcted myocardium (17.2 ± 2.4 vs 82.1 ± 10.8; p = 0.006 leading to a maximal relative SI (Signal Intensity between those two areas (344.9 ± 60.4. Conclusion Despite the rapid heart rate in mice, our study demonstrates that LGE MRI can be performed at 9.4T using a protocol similar to the one used for clinical MR diagnosis of myocardial infarction.

  3. Evaluation of the in vitro stability of gadolinium (III) polyoxometalates

    International Nuclear Information System (INIS)

    Crooks, William J.; Choppin, Gregory R.; Rogers, Buck E.; Welch, Michael

    1997-01-01

    The gadolinium chelates of lacunary polyoxometalates were evaluated for in vitro stability against rat serum, diethylenetriaminepentaacetic acid (DTPA), endogenous metal cations, and DTPA-doped rat serum. The chelates dissociated rapidly in rat serum. Challenges by DTPA gave relatively slower dissociation rates, whereas challenges by endogenous metal cations (Fe(III), Zn(II), and Cu(II)) occurred at a rate comparable to the serum challenge, suggesting the instability in serum is due to a transmetalation mechanism. Challenges by DTPA-doped serum gave slower rates of dissociation than in native serum, verifying the transmetalation mechanism

  4. Behavior of gadolinium-based diagnostics in water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cyris, Maike

    2013-04-25

    Wastewater treatment plants throughout Europe are retrofitted for a sufficient removal of micropollutants. Most target compounds are eliminated efficiently at reasonable costs by oxidation. Sorption processes, on the other hand, are favored as no transformation products are formed. For oxidation, ozone is preferred presently. Its action is divided in two main reaction pathways: Via ozone and via hydroxyl radicals formed by ozone-matrix reactions. Oxidation efficiency strongly depends on reaction rate constants. Sorption processes are usually characterized, including sorption strength, by determination of isotherms. Also, for description of filtration processes isotherm data are necessary. So far, gadolinium chelates, used as contrast agents in magnetic resonance imaging, have not been investigated in both advanced wastewater treatment processes. The stable chelates are excreted without metabolization. Conventional wastewater treatment does not remove them substantially. They remain intact and no free Gd(III) is released. This may be changed due to oxidative treatment which potentially destroys the chelates, and Gd(III) ions which are toxic, contrary to the chelated form, may be liberated. Monitoring campaigns in wastewater and drinking water have been performed to demonstrate the relevance of gadolinium in such treatment steps. In a European monitoring campaign an average concentration of 118 ng L{sup -1} gadolinium has been determined for 75 wastewater treatment plants effluents, corresponding to a non-geogenic gadolinium concentration of 116 ng L{sup -1}. In drinking water in the Ruhr area, a densely populated region in Germany, gadolinium and the anomaly were measurable by a factor of five lower than the average in the investigated wastewater samples. The determined concentrations in drinking water are lower than acute toxic effect concentration. The speciation of gadolinium in the investigated samples is unknown, as only total element concentration has been

  5. Behavior of gadolinium-based diagnostics in water treatment

    International Nuclear Information System (INIS)

    Cyris, Maike

    2013-01-01

    Wastewater treatment plants throughout Europe are retrofitted for a sufficient removal of micropollutants. Most target compounds are eliminated efficiently at reasonable costs by oxidation. Sorption processes, on the other hand, are favored as no transformation products are formed. For oxidation, ozone is preferred presently. Its action is divided in two main reaction pathways: Via ozone and via hydroxyl radicals formed by ozone-matrix reactions. Oxidation efficiency strongly depends on reaction rate constants. Sorption processes are usually characterized, including sorption strength, by determination of isotherms. Also, for description of filtration processes isotherm data are necessary. So far, gadolinium chelates, used as contrast agents in magnetic resonance imaging, have not been investigated in both advanced wastewater treatment processes. The stable chelates are excreted without metabolization. Conventional wastewater treatment does not remove them substantially. They remain intact and no free Gd(III) is released. This may be changed due to oxidative treatment which potentially destroys the chelates, and Gd(III) ions which are toxic, contrary to the chelated form, may be liberated. Monitoring campaigns in wastewater and drinking water have been performed to demonstrate the relevance of gadolinium in such treatment steps. In a European monitoring campaign an average concentration of 118 ng L -1 gadolinium has been determined for 75 wastewater treatment plants effluents, corresponding to a non-geogenic gadolinium concentration of 116 ng L -1 . In drinking water in the Ruhr area, a densely populated region in Germany, gadolinium and the anomaly were measurable by a factor of five lower than the average in the investigated wastewater samples. The determined concentrations in drinking water are lower than acute toxic effect concentration. The speciation of gadolinium in the investigated samples is unknown, as only total element concentration has been determined

  6. Gadolinium photoionization process

    Science.gov (United States)

    Paisner, Jeffrey A.; Comaskey, Brian J.; Haynam, Christopher A.; Eggert, Jon H.

    1993-01-01

    A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.

  7. An instrument assessing satisfaction with iron chelation therapy: Psychometric testing from an open-label clinical trial.

    Science.gov (United States)

    Rofail, Diana; Viala, Muriel; Gater, Adam; Abetz-Webb, Linda; Baladi, Jean-Francois; Cappellini, Maria Domenica

    2010-08-01

    The Satisfaction with Iron Chelation Therapy (SICT) instrument was developed based on a literature review, in-depth patient and clinician interviews, and cognitive debriefing interviews. An, open-label, single arm, multicenter trial evaluating the efficacy and safety of deferasirox in patients diagnosed with transfusion-dependent iron overload, provided an opportunity to assess the psychometric measurement properties of the instrument. Psychometric analyses were performed using data at baseline from 273 patients with a range of transfusion-dependent iron overload conditions who were participating in a multinational study. Responsiveness was further evaluated for all patients who also had subsequent satisfaction domain scores collected at week 4. Baseline SICT domain scores had acceptable floor and ceiling effects and internal consistency reliability (Cronbach's alpha: 0.75-0.85). Item discriminant and item convergent validity were both excellent although one item in each analysis did not meet the specified criterion. Small to moderate correlations were observed between SICT and Short Form 36 Health Survey (SF-36) domain scores. Patients with the highest levels of serum ferritin at baseline (>3100 ng/mL) were the least satisfied about the Perceived Effectiveness of ICT and vice versa. Satisfaction improved in all patients, although there were no clear differences observed between groups of patients defined according to changes in serum ferritin levels from baseline to week 4 (stable, improved, or worsened). The SICT domains are reliable and valid. Further testing using a more specific criterion (such as assessing patient global ratings of change in satisfaction domains that correspond to the SICT domains) could help to establish with greater confidence the responsiveness of the instrument.

  8. Diagnosis of occlusive arterial disease and assessment of IVR with fat-suppressed gadolinium-enhanced three-dimensional MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Yasuo; Gemma, Kazuhito; Kawamata, Hiroshi; Okajima, Yuhji; Watari, Jun; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan); Maki, Toshio; Tsuchihashi, Toshio

    1996-10-01

    Fat-suppressed gadolinium-enhanced three-dimensional MR angiography (FS-CE-3D-MRA) was performed to make a diagnosis of occlusive arterial disease and evaluate the effectiveness of IVR treatment for it. FS-CE-3D-MRA delineated stenosis of common iliac arteries, which was confirmed by X-ray angiography. FS-CE-3D-MRA also detected ulcerated plaque and arterial wall irregularity. The effectiveness of IVR as atherectomy and stent placement was accurately assessed with FS-CE-3D-MRA. FS-CE-3D-MRA was useful in evaluating occlusive arterial disease with short examination times and high spatial resolution, although iliac circumflexial arteries were not detected by this technique. (author)

  9. Diagnostic significance of gadolinium-DTPA (diethylenetriamine penta-acetic acid) enhanced magnetic resonance imaging in thrombolytic treatment for acute myocardial infarction: its potential in assessing reperfusion.

    Science.gov (United States)

    van der Wall, E E; van Dijkman, P R; de Roos, A; Doornbos, J; van der Laarse, A; Manger Cats, V; van Voorthuisen, A E; Matheijssen, N A; Bruschke, A V

    1990-01-01

    The diagnostic value of gadolinium-DTPA (diethylenetriamine penta-acetic acid) enhanced magnetic resonance imaging in patients treated by thrombolysis for acute myocardial infarction was assessed in 27 consecutive patients who had a first acute myocardial infarction (14 anterior, 13 inferior) and who underwent thrombolytic treatment and coronary arteriography within 4 hours of the onset of symptoms. Magnetic resonance imaging was performed 93 hours (range 15-241) after the onset of symptoms. A Philips Gyroscan (0.5 T) was used, and spin echo measurements (echo time 30 ms) were made before and 20 minutes after intravenous injection of 0.1 mmol/kg gadolinium-DTPA. In all patients contrast enhancement of the infarcted areas was seen after Gd-DTPA. The signal intensities of the infarcted and normal values were used to calculate the intensity ratios. Mean (SD) intensity ratios after Gd-DTPA were significantly increased (1.15 (0.17) v 1.52 (0.29). Intensity ratios were higher in the 17 patients who underwent magnetic resonance imaging more than 72 hours after the onset of symptoms than in the 10 who underwent magnetic resonance imaging earlier, the difference being significantly greater after administration of Gd-DTPA (1.38 (0.12) v 1.61 (0.34). When patients were classified according to the site and size of the infarcted areas, or to reperfusion (n = 19) versus non-reperfusion (n = 8), the intensity ratios both before and after Gd-DTPA did not show significant differences. Magnetic resonance imaging with Gd-DTPA improved the identification of acutely infarcted areas, but with current techniques did not identify patients in whom thrombolytic treatment was successful. Images PMID:2310640

  10. Gadolinium-based contrast agent toxicity: a review of known and proposed mechanisms.

    Science.gov (United States)

    Rogosnitzky, Moshe; Branch, Stacy

    2016-06-01

    Gadolinium chelates are widely used as contrast media for magnetic resonance imaging. The approved gadolinium-based contrast agents (GBCAs) have historically been considered safe and well tolerated when used at recommended dosing levels. However, for nearly a decade, an association between GBCA administration and the development of nephrogenic systemic fibrosis (NSF) has been recognized in patients with severe renal impairment. This has led to modifications in clinical practices aimed at reducing the potential and incidence of NSF development. Newer reports have emerged regarding the accumulation of gadolinium in various tissues of patients who do not have renal impairment, including bone, brain, and kidneys. Despite the observations of gadolinium accumulation in tissues regardless of renal function, very limited clinical data regarding the potential for and mechanisms of toxicity is available. This significant gap in knowledge warrants retrospective cohort study efforts, as well as prospective studies that involve gadolinium ion (Gd(3+)) testing in patients exposed to GBCA. This review examines the potential biochemical and molecular basis of gadolinium toxicity, possible clinical significance of gadolinium tissue retention and accumulation, and methods that can limit gadolinium body burden.

  11. Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging of brain tumors: a short temporal interval assessment.

    Science.gov (United States)

    Li, Xiang; Qu, Jin-Rong; Luo, Jun-Peng; Li, Jing; Zhang, Hong-Kai; Shao, Nan-Nan; Kwok, Keith; Zhang, Shou-Ning; Li, Yan-le; Liu, Cui-Cui; Zee, Chi-Shing; Li, Hai-Liang

    2014-09-01

    To determine the effect of intravenous administration of gadolinium (Gd) contrast medium (Gd-DTPA) on diffusion-weighted imaging (DWI) for the evaluation of normal brain parenchyma vs. brain tumor following a short temporal interval. Forty-four DWI studies using b values of 0 and 1000 s/mm(2) were performed before, immediately after, 1 min after, 3 min after, and 5 min after the administration of Gd-DTPA on 62 separate lesions including 15 meningioma, 17 glioma and 30 metastatic lesions. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values of the brain tumor lesions and normal brain tissues were measured on pre- and postcontrast images. Statistical analysis using paired t-test between precontrast and postcontrast data were obtained on three brain tumors and normal brain tissue. The SNR and CNR of brain tumors and the SNR of normal brain tissue showed no statistical differences between pre- and postcontrast (P > 0.05). The ADC values on the three cases of brain tumors demonstrated significant initial increase on the immediate time point (P < 0.01) and decrease on following the 1 min time point (P < 0.01) after contrast. Significant decrease of ADC value was still found at 3min and 5min time point in the meningioma group (P < 0.01) with gradual normalization over time. The ADC values of normal brain tissues demonstrated significant initial elevation on the immediately postcontrast DWI sequence (P < 0.01). Contrast medium can cause a slight but statistically significant change on the ADC value within a short temporal interval after the contrast administration. The effect is both time and lesion-type dependent. © 2013 Wiley Periodicals, Inc.

  12. Heavy metal staining, a comparative assessment of gadolinium chloride and osmium tetroxide for inner ear labyrinthine contrast enhancement using X-ray microtomography.

    Science.gov (United States)

    Wong, Christopher C; Curthoys, Ian S; O'Leary, Stephen J; Jones, Allan S

    2013-01-01

    The use of both gadolinium chloride (GdCl(3)) and osmium tetroxide (OsO(4)) allowed for the visualization of the membranous labyrinth and other intralabyrinthine structures, at different intensities, as compared with the control sample. This initial comparison shows the advantages of GdCl(3) in radiological assessments and OsO(4) in more detailed anatomical studies and pathways of labyrinthine pathogenesis using X-ray microtomography (microCT). To assess an improved OsO(4) staining protocol and compare the staining affinities against GdCl(3). Guinea pig temporal bones were stained with either GdCl(3) (2% w/v) for 7 days or OsO(4) (2% w/v) for 3 days, and scanned in a microCT system. The post-scanned datasets were then assessed in a 3D rendering program. The enhanced soft tissue contrast as presented in the temporal bones stained with either GdCl(3) or OsO(4) allowed for the membranous labyrinth to be visualized throughout the whole specimen. GdCl(3)-stained specimens presented more defined contours of the bone profile in the radiographs, while OsO(4)-stained specimens provided more anatomical detail of individual intralabyrinthine structures, hence allowing spatial relationships to be visualized with ease in a 3D rendering context and 2D axial slice images.

  13. Assessment of potential aluminum chelators in an octanol/aqueous system and in the aluminum-loaded rabbit.

    Science.gov (United States)

    Yokel, R A; Kostenbauder, H B

    1987-11-01

    Aluminum (Al) solubilization from Al borate and its distribution in an octanol/aqueous system (Do/w) were determined in the absence and presence of 12 potential Al chelators. Citrate, N,N'-bis-(2-hydroxybenzyl)ethylenediamine- N,N'-diacetic acid (HBED), cyclohexane-1,2-diaminotetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), desferrioxamine, and ethylenediamine-N,N'-bis(2-dihydroxyphenylacetic acid) (EDDHA) were 55 to over 100% efficient in solubilizing equimolar amounts of Al. Tetracycline, EDTA, and 2,3-dihydroxybenzoic acid (DHBA) were less than 20% efficient. 1,4-Dioxane and fluoride were ineffective. The Do/w of Al averaged 0.005. The Do/w of the Al.chelator complex was generally less than that of Al, except for HBED and tetracycline (0.04 and 0.96, respectively). The Do/w of DHBA, desferrioxamine, EDDHA, and HBED were not influenced by Al, but tetracycline became more lipophilic. These compounds were tested for their ability to increase urinary Al excretion in Al-loaded rabbits. Chelators were given po weekly beginning 2 weeks after Al loading. Urine was obtained hourly from 3 hr prior to 6 hr after chelator administration and analyzed for Al. Fluoride and tetracycline (450 and 4500 mumol/kg) and citrate, NTA, EDTA, CDTA, DTPA, DHBA, HBED, and 1,4-dioxane (150 and 1500 mumol/kg) were ineffective. Following HBED administration, some of the Al-loaded rabbits died, presumably due to redistribution of Al within the rabbit. Following DTPA administration, some of the Al-loaded rabbits died, presumably due to DTPA. Oral EDDHA (1500 mumol/kg) significantly increased urinary Al excretion. EDDHA and desferrioxamine (150 mumol/kg) were administered by po, sc, and iv routes and were found to have comparable potency. The in vitro results may explain some of the in vivo findings. The in vitro methods may be useful to screen out compounds with no chelation potential. EDDHA-like compounds may have potential as alternatives to

  14. Chelation in Metal Intoxication

    Directory of Open Access Journals (Sweden)

    Swaran J.S. Flora

    2010-06-01

    Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

  15. High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

    Energy Technology Data Exchange (ETDEWEB)

    Meux, Susan C.; Datta, Ankona; Hooker, Jacob M.; Botta, Mauro; Francis, Matthew B.; Aime, Silvio; Raymond, Kenneth N.

    2007-08-29

    High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) there is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups.

  16. Beliefs about chelation among thalassemia patients

    Directory of Open Access Journals (Sweden)

    Trachtenberg Felicia L

    2012-12-01

    Full Text Available Abstract Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC of the Thalassemia Clinical Research Network (TCRN. Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks. Results Of 371 patients (ages 5-58y, mean 24y, 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump, 63% oral, 11% combination. Patients expressed high “necessity” for transfusion (96%, DFO chelation (92% and oral chelation (89%, with lower “concern” about treatment (48%, 39%, 19% respectively. Concern about oral chelation was significantly lower than that of DFO (p Conclusions Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden. Clinicaltrials.gov identifier NCT00661804

  17. Characteristics of gadolinium-DTPA complex: a potential NMR contrast agent

    International Nuclear Information System (INIS)

    Weinmann, H.J.; Brasch, R.C.; Press, W.R.; Wesbey, G.E.

    1984-01-01

    Chelation of the rare-earth element gadolinium (Gd) with diethylenetriaminepentaacetic acid (DTPA) results in a strongly paramagnetic, stable complex that is well tolerated in animals. The strongly paramagnetic gadolinium complex reduces hydrogen-proton relaxation times even in low concentrations (less than 0.01 mmol/L). The pharmacokinetic behavior of intravenously delivered Gd-DTPA is similar to the well known iodinated contrast agents used in urography and angiography; excretion is predominately through the kidneys with greater than 90% recovery in 24 hr. The intravenous LD 50 of the meglumine salt of Gd-DTPA is 10 mmol/kg for the rat; in vivo there is no evidence of dissociation of the gadolinium ion from the DTPA ligand. The combination of strong proton relaxation, in-vivo stability, rapid urinary excretion, and high tolerance favors the further development and the potential clinical application of gadolinium-DTPA as a contrast enhancer in magnetic resonance imaging

  18. Robust assessment of the transmural extent of myocardial infarction in late gadolinium-enhanced MRI studies using appropriate angular and circumferential subdivision of the myocardium

    International Nuclear Information System (INIS)

    Kachenoura, Nadjia; Herment, Alain; Frouin, Frederique; Redheuil, Alban; Mousseaux, Elie

    2008-01-01

    A computer-assisted method is proposed to estimate transmural extent of myocardial infarction. In 40 patients with chronic myocardial infarction and 3 control subjects, late gadolinium enhancement images were acquired with magnetic resonance imaging. Segmental infarct transmural extent was visually assessed by two experts on a 5-point scale. A fuzzy c-means algorithm was applied on both the cavity and myocardium to estimate an enhancement index for 12 sub-regions of each segment. A threshold was defined on a training database (n=29) to establish the transmurality extent of each sub-segment and was applied to the validation database (n=14). Inter-observer reproducibility reached an absolute agreement (Aa) of 85% and a kappa value (κ) of 0.83 when considering the whole training database; Aa decreased to 62% and κ to 0.68 when excluding homogeneous segments. On the validation database, segments were subdivided into three angular sub-segments. Then, inter-observer visual reproducibility reached Aa of 93% and κ of 0.92. Moreover, the absolute comparison of each expert with the computer-assisted method yielded Aa higher than 88% and κ higher than 0.86. The computer-assisted method quantifies infarct transmurality without defining remote and infarcted regions, and the transmural extent is accurately characterized when dividing each segment into three angular sub-segments. (orig.)

  19. Gadolinium depletion event in a CANDU® moderator - causes and recovery

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.W.; Price, J.; Swami, D.; Fracalanza, E.; Brett, M.E.; Puzzuoli, F.V.; Garg, A. [Ontario Power Generation, Pickering, Ontario (Canada); Herrmann, O.; Rudolph, A. [Kinectrics Inc., Toronto, Ontario (Canada); Stuart, C.; Glowa, G. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Smee, J. [Niagara Technical Consultants, St. Catharines, Ontario (Canada)

    2010-07-01

    ) developing solvents for dissolution of the gadolinium oxalate deposits and 2) assessing the potential for radiolytic (or other) degradation of in-core gadolinium oxalate. As expected, the oxalate was found to be readily dissolved by chelant solutions, especially the ammonium salts of EDTA. However, EDTA was less suitable for in-core cleaning, since the shutdown gamma fields (2 kGy/hour) rapidly degraded the chelant and resulted in radiogenic H{sub 2}. Inorganic solvents, including acidic solutions of ceric ammonium nitrate, persulphate salts and permanganate were also evaluated. Testing indicated that the inorganic solvents were prone to some radiolysis effects and exhibited relatively high corrosion rates for some moderator system materials. Subsequent remote inspection of in-core surfaces and characterization of the deposits on a calandria tube removed from this unit showed that the gadolinium oxalate had converted to the readily-soluble gadolinium nitrate, by mechanisms that are currently under investigation. As a result, the decision was made to refill the moderator, during which virtually all of the in-core gadolinium was found to re-dissolve. The unit was successfully returned to service, with the normal approach-to-critical confirming the absence of residual in-core gadolinium deposits. Investigations continue, under the auspices of the CANDU Owners Group, into the specific conditions favouring the formation of oxalate in the CANDU moderator and the factors responsible for the in-core conversion of gadolinium oxalate to the nitrate during the outage. Chemistry control specifications have been developed to limit the allowable levels of CO{sub 2} species in the moderator water and cover gas. (author)

  20. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  1. Chelation in metal intoxication

    DEFF Research Database (Denmark)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, yang

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the incon......The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...

  2. EDTA chelation therapy alone and in combination with oral high-dose multivitamins and minerals for coronary disease: The factorial group results of the Trial to Assess Chelation Therapy.

    Science.gov (United States)

    Lamas, Gervasio A; Boineau, Robin; Goertz, Christine; Mark, Daniel B; Rosenberg, Yves; Stylianou, Mario; Rozema, Theodore; Nahin, Richard L; Terry Chappell, L; Lindblad, Lauren; Lewis, Eldrin F; Drisko, Jeanne; Lee, Kerry L

    2014-07-01

    Disodium ethylenediaminetetraacetic acid (EDTA) reduced adverse cardiac outcomes in a factorial trial also testing oral vitamins. This report describes the intent-to-treat comparison of the 4 factorial groups overall and in patients with diabetes. This was a double-blind, placebo-controlled, 2 × 2 factorial multicenter randomized trial of 1,708 post-myocardial infarction (MI) patients ≥50 years of age and with creatinine ≤2.0 mg/dL randomized to receive 40 EDTA chelation or placebo infusions plus 6 caplets daily of a 28-component multivitamin-multimineral mixture or placebo. The primary end point was a composite of total mortality, MI, stroke, coronary revascularization, or hospitalization for angina. Median age was 65 years, 18% were female, 94% were Caucasian, 37% were diabetic, 83% had prior coronary revascularization, and 73% were on statins. Five-year Kaplan-Meier estimates for the primary end point was 31.9% in the chelation + high-dose vitamin group, 33.7% in the chelation + placebo vitamin group, 36.6% in the placebo infusion + active vitamin group, and 40.2% in the placebo infusions + placebo vitamin group. The reduction in primary end point by double active treatment compared with double placebo was significant (hazard ratio 0.74, 95% CI 0.57-0.95, P = .016). In patients with diabetes, the primary end point reduction of double active compared with double placebo was more pronounced (hazard ratio 0.49, 95% CI 0.33-0.75, P < .001). In stable post-MI patients on evidence-based medical therapy, the combination of oral high-dose vitamins and chelation therapy compared with double placebo reduced clinically important cardiovascular events to an extent that was both statistically significant and of potential clinical relevance. Copyright © 2014 The Authors. Published by Mosby, Inc. All rights reserved.

  3. Chelation in root canal therapy reconsidered.

    Science.gov (United States)

    Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

    2005-11-01

    The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.

  4. Gadolinium-enhanced 7.0 T magnetic resonance imaging assessment of the aqueous inflow in rat eyes in vivo.

    Science.gov (United States)

    Li, Lu; Yuan, Yuxiang; Chen, Liwen; Li, Mu; Ji, Pingting; Gong, Jieling; Zhao, Yin; Zhang, Hong

    2017-09-01

    The goal of this study was to calculate the anterior chamber volume and assess aqueous inflow in rat eyes in vivo, under anesthetic condition. Gadolinium-contrast agent (Gd-DTPA, 234.5 mg/ml) was administered to Sprague-Dawley rat eyes via anterior chamber injection or instillation of 234.5 or 117.25 mg/ml Gd-DTPA in 0.2% azone as eye drops, and changes of Gd signal visualized by 7.0 T magnetic resonance imaging (MRI). The safety of local application of Gd-DTPA and azone were performed after MRI scanning. The anterior chamber injection of Gd-DTPA (234.5 mg/ml) group was used for anterior chamber volume and aqueous inflow calculating. Serial changes in Gd-DTPA relative concentration in the anterior chamber was determined based on the initial Gd signal gray values and the initial relative concentration of Gd-DTPA after anterior chamber Gd-DTPA injection. The mean aqueous inflow in rat eyes in vivo was assessed based on changes in Gd-DTPA relative concentration and the anterior chamber volume. Eye drops of Gd-DTPA (234.5 mg/ml) in 0.2% azone readily allowed safe assessment of the aqueous inflow by 7.0 T MRI. Under anesthetic condition in vivo, the mean anterior chamber volume (ACV) in rats was 8493.6 ± 657.4 μm 3 , no differences were observed in the aqueous inflow measured by topical instillation of 234.5 mg/ml Gd-DTPA in 0.2% azone (0.182 ± 0.011 μl/min) between that measured by anterior chamber injection (0.165 ± 0.041 μl/min, P > 0.05), Timolol reduced aqueous inflow to 0.124 ± 0.020 μl/min (P DTPA can be assessed by the variability of relative concentration of Gd-DTPA in anterior chamber and ACV in vivo, under anesthetic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. A new tool for the assessment of satisfaction with iron chelation therapy (ICT-Sat) for patients with β-thalassemia major.

    Science.gov (United States)

    Elalfy, Mohsen S; Massoud, Walid; Elsherif, Nayera H; Labib, Jonair H; Elalfy, Omar M; Elaasar, Safaa; von Mackensen, Sylvia

    2012-06-01

    High satisfaction with iron chelation is a major determinant for adherence to ICT in beta-thalassaemia major (β-TM) patients. In this study, a new tool to assess different domains of satisfaction for available forms of ICT was developed and validated. The impact of patients' satisfaction with ICT has been tested. Items were generated via focus groups and a preliminary version with 24 items (ICT-Sat) with an additional item for treatment preference and a knowledge questionnaire (KQ) was developed. 170 β-TM patients from three Thalassaemia centers in Egypt, aged 2-32 years received three questionnaires to fill in; the new ICT-Sat, a KQ, and a previously validated tool for satisfaction with ICT (SICT) and retested 4-6 weeks later to ensure re-test reliability. Type of chelation, drug related adverse events, compliance with ICT, and serum ferritin level (SF) during the year prior to the study as well as available cardiac T2*data were recorded. One hundred and fifty two β-TM patients completed all questionnaires; median age was 12 years. The final 15 remaining ICT-Sat items, yielding to four domain scores, explained 70.6% of the total variance. The "perceived effectiveness" and "fear and worries" domains of the ICT-Sat correlated significantly with the domains "perceived effectiveness" and "acceptance" of the SICT. Patients treated with oral ICT were more satisfied with perceived effectiveness, and their side effects. A new clinically based ICT-Sat tool was developed and revealed good psychometric characteristics. Adherence to ICT was better correlated with "perceived effectiveness" and SF level. Copyright © 2012 Wiley Periodicals, Inc.

  6. Impact of gadolinium-based contrast agent in the assessment of Crohn's disease activity: Is contrast agent injection necessary?

    Science.gov (United States)

    Quaia, Emilio; Sozzi, Michele; Gennari, Antonio Giulio; Pontello, Michele; Angileri, Roberta; Cova, Maria Assunta

    2016-03-01

    To determine whether magnetic resonance enterography (MRE) performed without intravenous contrast injection is diagnostically noninferior to conventional contrast-enhanced MRE (CE-MRE) in patients with Crohn's disease (CD). This was an Institutional Review Board (IRB)-approved retrospective study. Ninety-six patients (52 male and 44 female; 47.18 years ± 13.6) with a diagnosis of CD underwent MRE at 1.5T including T2 -weighted single-shot turbo-spin-echo, T2 -weighted spectral fat presaturation with inversion recovery (SPAIR), T1 -weighted balanced fast-field-echo MR sequences, and CE-MRE consisting in T1 -weighted breath-hold THRIVE 3D MRI sequences after administration of gadobenate dimeglumine (0.2 mL/kg of body weight). Unenhanced MRE, CE-MRE, and unenhanced MRE plus CE-MRE were reviewed in separate sessions with blinding by two readers in consensus, and subsequently by two other readers independently considering a subgroup of 20 patients. Crohn's Disease Endoscopic Index of Severity (CDEIS) and/or histologic analysis of the surgical specimen were considered as reference standards for the assessment of inflammatory activity. Patients revealed prevalently active (n = 55 patients) or quiescent CD (n = 41 patients). The agreement between unenhanced MRE vs. CE-MRE in interpreting active bowel inflammation was 96% (123/128 bowel segments; one-sided 95% confidence interval [CI], >94.4%). Unenhanced MRE vs. CE-MRE vs. unenhanced MRE plus CE-MRE revealed a diagnostic accuracy of 93% [90/96] vs. 92% [88/96] vs. 97% [93/96] (P > 0.05) in the diagnosis of active CD. Interreader agreement was very good for all variables (κ value = 0.8-0.9) except for the measurement of the length of disease (κ value = 0.45). Unenhanced MRE was noninferior to CE-MRE in diagnosing active inflammation in patients with CD. © 2015 Wiley Periodicals, Inc.

  7. Assessment of Degree of Applicability of Benchmarks for Gadolinium Using KENO V.a and the 238-Group SCALE Cross-Section Library

    Energy Technology Data Exchange (ETDEWEB)

    Goluoglu, S.

    2003-12-01

    A review of the degree of applicability of benchmarks containing gadolinium using the computer code KENO V.a and the gadolinium cross sections from the 238-group SCALE cross-section library has been performed for a system that contains {sup 239}Pu, H{sub 2}O, and Gd{sub 2}O{sub 3}. The system (practical problem) is a water-reflected spherical mixture that represents a dry-out condition on the bottom of a sludge receipt and adjustment tank around steam coils. Due to variability of the mixture volume and the H/{sup 239}Pu ratio, approximations to the practical problem, referred to as applications, have been made to envelop possible ranges of mixture volumes and H/{sup 239}Pu ratios. A newly developed methodology has been applied to determine the degree of applicability of benchmarks as well as the penalty that should be added to the safety margin due to insufficient benchmarks.

  8. Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  9. Comments on chelation therapy

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1981-01-01

    The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239 Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241 Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241 Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

  10. Assessing the effect of football play on knee articular cartilage using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC).

    Science.gov (United States)

    Wei, Wenbo; Lambach, Becky; Jia, Guang; Flanigan, David; Chaudhari, Ajit M W; Wei, Lai; Rogers, Alan; Payne, Jason; Siston, Robert A; Knopp, Michael V

    2017-06-01

    The prevalence of cartilage lesions is much higher in football athletes than in the general population. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been shown to quantify regional variations of glycosaminoglycan (GAG) concentrations which is an indicator of early cartilage degeneration. The goal of this study is to determine whether dGEMRIC can be used to assess the influence in cartilage GAG concentration due to college level football play. Thirteen collegiate football players with one to four years of collegiate football play experience were recruited and both knee joints were scanned using a dedicated 8-channel phased array knee coil on a 3T MRI system. The contrast concentrations within cartilage were calculated based on the T 1 values from dGEMRIC scans. No substantial differences were found in the contrast concentrations between the pre- and post-season across all the cartilage compartments. One year collegiate football players presented an average contrast concentration at the pre-season of 0.116±0.011mM and post-season of 0.116±0.011mM. In players with multiple years of football play, contrast uptake was elevated to 0.141±0.012mM at the pre-season and 0.139±0.012mM at the post-season. The pre-season 0.023±0.016mM and post-season 0.025±0.016mM increase in contrast concentration within the group with multiple years of experience presented with a >20% increase in contrast uptake. This may indicate the gradual, cumulative damage of football play to the articular cartilage over years, even though the effect may not be noticeable after a season of play. Playing collegiate football for a longer period of time may lead to cartilage microstructural alterations, which may be linked to early knee cartilage degeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Preclinical studies on gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Akine, Yasuyuki

    1994-01-01

    Gadolinium neutron capture therapy is based on radiations (photons and electrons) produced in the tumor by a nuclear reaction between gadolinium and lower-energy neutrons. Studies with Chinese hamster cells have shown that the radiation effect resulting from gadolinium neutron capture reactions is mostly of low LET and that released electrons are the significant component in the over-all dose. Biological dosimetry revealed that the dose does not seem to increase in proportion to the gadolinium concentration, leading to a conclusion that there is a range of gadolinium concentrations most efficient for gadolinium neutron capture therapy. The in vivo studies with transplantable tumors in mice and rabbits have revealed that close contact between gadolinium and the cell is not necessarily required for cell inactivation and that gadolinium delivery selective to tumors is crucial. The results show that the potential of gadolinium neutron capture therapy as a therapeutic modality appears very promising. (author)

  12. Chelation Therapy for Mercury Poisoning

    OpenAIRE

    Rong Guan; Han Dai

    2009-01-01

    Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

  13. Assessment of antioxidative, chelating, and DNA-protective effects of selected essential oil components (eugenol, carvacrol, thymol, borneol, eucalyptol) of plants and intact Rosmarinus officinalis oil.

    Science.gov (United States)

    Horvathova, Eva; Navarova, Jana; Galova, Eliska; Sevcovicova, Andrea; Chodakova, Lenka; Snahnicanova, Zuzana; Melusova, Martina; Kozics, Katarina; Slamenova, Darina

    2014-07-16

    Selected components of plant essential oils and intact Rosmarinus officinalis oil (RO) were investigated for their antioxidant, iron-chelating, and DNA-protective effects. Antioxidant activities were assessed using four different techniques. DNA-protective effects on human hepatoma HepG2 cells and plasmid DNA were evaluated with the help of the comet assay and the DNA topology test, respectively. It was observed that whereas eugenol, carvacrol, and thymol showed high antioxidative effectiveness in all assays used, RO manifested only antiradical effect and borneol and eucalyptol did not express antioxidant activity at all. DNA-protective ability against hydrogen peroxide (H2O2)-induced DNA lesions was manifested by two antioxidants (carvacrol and thymol) and two compounds that do not show antioxidant effects (RO and borneol). Borneol was able to preserve not only DNA of HepG2 cells but also plasmid DNA against Fe(2+)-induced damage. This paper evaluates the results in the light of experiences of other scientists.

  14. Design, synthesis, and evaluation of gadolinium cationic lipids as tools for biodistribution studies of gene delivery complexes.

    Science.gov (United States)

    Leclercq, Francoise; Cohen-Ohana, Mirit; Mignet, Nathalie; Sbarbati, Andrea; Herscovici, Jean; Scherman, Daniel; Byk, Gerardo

    2003-01-01

    Gadolinium-chelating cationic lipids have been synthesized to obtain lipoplexes with MRI contrast properties. These compounds were designed to follow the biodistribution of synthetic DNA for gene delivery by nuclear magnetic resonance imaging. The lipid MCO-I-68 was synthesized, and chelate complexes with gadolinium were formed and characterized in terms of physicochemical and DNA binding properties. The transfection activity of MCO-I-68-Gd/DNA complexes was assayed in vitro on NIH 3T3. Different formulations of the product were tested. When up to 5% of the gadolinium lipid complexes were co-formulated with the cationic lipid RPR120535 used as a reference, the transfection levels were maintained as compared to RPR120535 alone. To date, only a liposomal formulation of a gadolinium-cationic lipid chelate without DNA had been observed using magnetic resonance imaging. In vivo intratumoral administration of MCO-I-68-Gd/DNA lipoplexes to tumor model led to an important increase of the NMR signal. It was demonstrated that the new complexes also acted as transfection carriers when they were formulated from liposomes.

  15. Validation of gadolinium burnout using PWR benchmark specification

    Energy Technology Data Exchange (ETDEWEB)

    Oettingen, Mikołaj, E-mail: moettin@agh.edu.pl; Cetnar, Jerzy, E-mail: cetnar@mail.ftj.agh.edu.pl

    2014-07-01

    Graphical abstract: - Highlights: • We present methodology for validation of gadolinium burnout in PWR. • We model 17 × 17 PWR fuel assembly using MCB code. • We demonstrate C/E ratios of measured and calculated concentrations of Gd isotopes. • The C/E for Gd154, Gd156, Gd157, Gd158 and Gd160 shows good agreement of ±10%. • The C/E for Gd152 and Gd155 shows poor agreement below ±10%. - Abstract: The paper presents comparative analysis of measured and calculated concentrations of gadolinium isotopes in spent nuclear fuel from the Japanese Ohi-2 PWR. The irradiation of the 17 × 17 fuel assembly containing pure uranium and gadolinia bearing fuel pins was numerically reconstructed using the Monte Carlo Continuous Energy Burnup Code – MCB. The reference concentrations of gadolinium isotopes were measured in early 1990s at Japan Atomic Energy Research Institute. It seems that the measured concentrations were never used for validation of gadolinium burnout. In our study we fill this gap and assess quality of both: applied numerical methodology and experimental data. Additionally we show time evolutions of infinite neutron multiplication factor K{sub inf}, FIMA burnup, U235 and Gd155–Gd158. Gadolinium-based materials are commonly used in thermal reactors as burnable absorbers due to large neutron absorption cross-section of Gd155 and Gd157.

  16. Vascular-targeted photodynamic therapy with BF2-chelated Tetraaryl-Azadipyrromethene agents: a multi-modality molecular imaging approach to therapeutic assessment.

    LENUS (Irish Health Repository)

    Byrne, A T

    2009-11-03

    Photodynamic therapy (PDT) is a treatment modality for a range of diseases including cancer. The BF(2)-chelated tetraaryl-azadipyrromethenes (ADPMs) are an emerging class of non-porphyrin PDT agent, which have previously shown excellent photochemical and photophysical properties for therapeutic application. Herein, in vivo efficacy and mechanism of action studies have been completed for the lead agent, ADMP06.

  17. Influence of delayed gadolinium enhanced MRI of cartilage (dGEMRIC) protocol on T2-mapping: is it possible to comprehensively assess knee cartilage composition in one post-contrast MR examination at 3 Tesla?

    Science.gov (United States)

    Verschueren, J; van Tiel, J; Reijman, M; Bron, E E; Klein, S; Verhaar, J A N; Bierma-Zeinstra, S M A; Krestin, G P; Wielopolski, P A; Oei, E H G

    2017-09-01

    To evaluate the possibility of assessing knee cartilage with T2-mapping and delayed gadolinium enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in one post-contrast MR examination at 3 Tesla (T). T2 mapping was performed in 10 healthy volunteers at baseline; directly after baseline; after 10 min of cycling; and after 90 min delay, and in 16 osteoarthritis patients before and after intravenous administration of a double dose gadolinium dimeglumine contrast agent, reflecting key dGEMRIC protocol elements. Differences in T2 relaxation times between each timepoint and baseline were calculated for 6 cartilage regions using paired t tests or Wilcoxon signed-rank tests and the smallest detectable change (SDC). After cycling, a significant change in T2 relaxation times was found in the lateral weight-bearing tibial plateau (+1.0 ms, P = 0.04). After 90 min delay, significant changes were found in the lateral weight-bearing femoral condyle (+1.2 ms, P = 0.03) and the lateral weight-bearing tibial plateau (+1.3 ms, P = 0.01). In these regions of interests (ROIs), absolute differences were small and lower than the corresponding SDCs. T2-mapping after contrast administration only showed statistically significantly lower T2 relaxation times in the medial posterior femoral condyle (-2.4 ms, P T2 relaxation times that were not consistent and lower than the SDC in the majority of regions, our results suggest that T2-mapping and dGEMRIC can be performed reliably in a single imaging session to assess cartilage biochemical composition in knee osteoarthritis (OA) at 3 T. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  18. Chiral DOTA chelators as an improved platform for biomedical imaging and therapy applications.

    Science.gov (United States)

    Dai, Lixiong; Jones, Chloe M; Chan, Wesley Ting Kwok; Pham, Tiffany A; Ling, Xiaoxi; Gale, Eric M; Rotile, Nicholas J; Tai, William Chi-Shing; Anderson, Carolyn J; Caravan, Peter; Law, Ga-Lai

    2018-02-27

    Despite established clinical utilisation, there is an increasing need for safer, more inert gadolinium-based contrast agents, and for chelators that react rapidly with radiometals. Here we report the syntheses of a series of chiral DOTA chelators and their corresponding metal complexes and reveal properties that transcend the parent DOTA compound. We incorporated symmetrical chiral substituents around the tetraaza ring, imparting enhanced rigidity to the DOTA cavity, enabling control over the range of stereoisomers of the lanthanide complexes. The Gd chiral DOTA complexes are shown to be orders of magnitude more inert to Gd release than [GdDOTA] - . These compounds also exhibit very-fast water exchange rates in an optimal range for high field imaging. Radiolabeling studies with (Cu-64/Lu-177) also demonstrate faster labelling properties. These chiral DOTA chelators are alternative general platforms for the development of stable, high relaxivity contrast agents, and for radiometal complexes used for imaging and/or therapy.

  19. Vessel diameter measurements in gadolinium contrast-enhanced three-dimensional MRA of peripheral arteries

    NARCIS (Netherlands)

    Westenberg, J.J.M.; Geest, van der R.J.; Wasser, M.N.J.M.; Linden, van der E.L.; Walsum, van T.; Assen, van H.C.; Roos, de A.; Vanderschoot, J.; Reiber, J.H.C.

    2000-01-01

    In this study, the possibilities for quantification of vessel diameters of peripheral arteries in gadolinium contrast-enhanced magnetic resonance angiography (Gd CE MRA) were evaluated. Absolute vessel diameter measurements were assessed objectively and semi-automatically in maximum intensity

  20. The T2-Shortening Effect of Gadolinium and the Optimal Conditions for Maximizing the CNR for Evaluating the Biliary System: a Phantom Study

    International Nuclear Information System (INIS)

    Lee, Mi Jung; Kim, Myung Joon; Yoon, Choon Sik; Song, Si Young; Park, Kyung Soo; Kim, Woo Sun

    2011-01-01

    Clear depiction of the common bile duct is important when evaluating neonatal cholestasis in order to differentiate biliary atresia from other diseases. During MR cholangiopancreatography, the T2-shortening effect of gadolinium can increase the contrast-to-noise ratio (CNR) of the bile duct and enhance its depiction. The purpose of this study was to confirm, by performing a phantom study, the T2-shortening effect of gadolinium, to evaluate the effect of different gadolinium chelates with different gadolinium concentrations and different magnetic field strengths for investigating the optimal combination of these conditions, and for identifying the maximum CNR for the evaluation of the biliary system. MR imaging using a T2-weighted single-shot fast spin echo sequence and T2 relaxometry was performed with a sponge phantom in a syringe tube. Two kinds of contrast agents (Gd-DTPA and Gd-EOB-DTPA) with different gadolinium concentrations were evaluated with 1.5T and 3T scanners. The signal intensities, the CNRs and the T2 relaxation time were analyzed. The signal intensities significantly decreased as the gadolinium concentrations increased (p < 0.001) with both contrast agents. These signal intensities were higher on a 3T (p < 0.001) scanner. The CNRs were higher on a 1.5T (p < 0.001) scanner and they showed no significant change with different gadolinium concentrations. The T2 relaxation time also showed a negative correlation with the gadolinium concentrations (p < 0.001) and the CNRs showed decrease more with Gd-EOB-DTPA (versus Gd-DTPA; p < 0.001) on a 3T scanner (versus 1.5T; p < 0.001). A T2-shortening effect of gadolinium exhibits a negative correlation with the gadolinium concentration for both the signal intensities and the T2 relaxation time. A higher CNR can be obtained with Gd-DTPA on a 1.5T MRI scanner.

  1. Target binding improves relaxivity in aptamer-gadolinium conjugates.

    Science.gov (United States)

    Bernard, Elyse D; Beking, Michael A; Rajamanickam, Karunanithi; Tsai, Eve C; Derosa, Maria C

    2012-12-01

    MRI contrast agents (CA) have been heavily used over the past several decades to enhance the diagnostic value of the obtained images. From a design perspective, two avenues to improve the efficacy of contrast agents are readily evident: optimization of magnetic properties of the CA, and optimization of the pharmacokinetics and distribution of the CA in the patient. Contrast agents consisting of DNA aptamer-gadolinium(III) conjugates provide a single system in which these factors can be addressed simultaneously. In this proof-of-concept study, the 15mer thrombin aptamer was conjugated to diethylenetriaminepentaacetic (DTPA) dianhydride to form a monoamide derivative of the linear open-chain chelate present in the commonly used contrast agent Magnevist(®). The stability of the conjugated DNA aptamer-DTPA-Gd(III) chelate in a transmetallation study using Zn(II) was found to be similar to that reported for DTPA-Gd(III). Relaxivity enhancements of 35 ± 4 and 20 ± 1 % were observed in the presence of thrombin compared to a control protein at fields of 9.4 and 1.5 T, respectively. The inclusion of spacers between the aptamer and the DTPA to eliminate possible steric effects was also investigated but not found to improve the relaxation enhancement achieved in comparison to the unaltered aptamer conjugate.

  2. A polymeric fastener can easily functionalize liposome surfaces with gadolinium for enhanced magnetic resonance imaging.

    Science.gov (United States)

    Smith, Cartney E; Shkumatov, Artem; Withers, Sarah G; Yang, Binxia; Glockner, James F; Misra, Sanjay; Roy, Edward J; Wong, Chun-Ho; Zimmerman, Steven C; Kong, Hyunjoon

    2013-11-26

    Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization and, therefore, has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication.

  3. Investigation of gadolinium monophosphide at high temperatures

    International Nuclear Information System (INIS)

    Gordienko, S.P.; Gol'nik, V.F.; Mironov, K.E.

    1982-01-01

    Gadolinium monophosphide has been studied in vacuum at high temperatures using mass-spectrometric, chemical, X-ray phase and derivatographical analyses. It is established that gadolinium monophosphide at 2080-2465 K dissociates into atomic gadolinium, phosphorus and, P 2 molecules. According to Vant-Hoff and Gibbs-Helmholtz equations standard enthalpy of atomization ΔHsub(at) deg (298)=1027.3 kJ/mol and of formation ΔHsub(f) deg (298)=313.8 kJ/mol of gadolinium monophosphide are determined

  4. Gadolinium atom on neutron capture therapy

    International Nuclear Information System (INIS)

    Oda, Y.; Takagaki, M.; Miyatake, S.; Kikuchi, H.

    1994-01-01

    This report describes our measurements of gadolinium concentrations in several brain tumors obtained from fresh surgical specimens, as compared with corresponding concentrations in the blood. Moreover we tried to find out if the gadolinium concentration is high enough to use this compound in the treatment of brain tumors by neutron capture therapy. (J.P.N.)

  5. Assessment of lumbar intervertebral disc glycosaminoglycan content by gadolinium-enhanced MRI before and after 21-days of head-down-tilt bedrest.

    Directory of Open Access Journals (Sweden)

    Timmo Koy

    Full Text Available During spaceflight, it has been shown that intervertebral discs (IVDs increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC protocol before and after bedrest. The outcome measures were T1 and ΔT1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (ΔT1 were computed. ΔT1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT1 (p<0.001 after bedrest in all IVDs, and in all areas of the IVDs. The ΔT1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems

  6. In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

    Science.gov (United States)

    2014-01-01

    Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1 = 1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (ΔR1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ΔR1 were similar for double and triple doses of the contrast agent. ΔR1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ΔR1 increased until 90-180 minutes in both the cartilage and the meniscus (p meniscus at all time points (p meniscus, than in the avascular central part of the posterior medial meniscus during the first 60 minutes (p meniscus and cartilage simultaneously using dGEMRIC, preferably 90 minutes after the injection of a

  7. Use of dispersive liquid-liquid microextraction for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium

    International Nuclear Information System (INIS)

    Mallah, M.H.; Atomic Energy Organization of Iran, Tehran; Shemirani, F.; Ghannadi Maragheh, M.

    2008-01-01

    A new preconcentration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively. (author)

  8. Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study.

    Science.gov (United States)

    van Hamersvelt, Robbert W; Willemink, Martin J; de Jong, Pim A; Milles, Julien; Vlassenbroek, Alain; Schilham, Arnold M R; Leiner, Tim

    2017-09-01

    The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P  0.99, CI 0.99-1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. • Gadolinium quantification may be useful in patients with contraindication to iodine. • Dual-layer spectral detector CT allows for overall accurate quantification of gadolinium. • Interscan variability of gadolinium quantification using SDCT material decomposition is excellent.

  9. Article Commentary: Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  10. Use of gadolinium-DTPA

    International Nuclear Information System (INIS)

    Bydder, G.

    1990-01-01

    Early in the development of magnetic resonance imaging (MRI) it was apparent that a high level of soft tissue contrast was available de novo and it was thought that the need for externally administered contrast agents might be small. This observation was tempered by the fact that separation of tumor from edema was frequently better with contrast-enhanced X-ray computed tomography (CT) than with unenhanced MRI. It was therefore felt that a contrast agent might be needed for MRI. At the end of 1983 the first parenteral agent, gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) was used in volunteers, and clinical studies began in 1984. This paper discusses how, at present, Gd-DTPA, oral, and intravenous iron compounds are in clinical use

  11. Quantitative assessment of synovial inflammation by dynamic gadolinium-enhanced magnetic resonance imaging. A study of the effect of intra-articular methylprednisolone on the rate of early synovial enhancement

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Henriksen, O

    1996-01-01

    The effect of temporary inflammatory suppression on synovial membrane enhancement, as determined by dynamic and static gadolinium-DTPA enhanced magnetic resonance imaging (MRI), was studied. MRI of 18 arthritic knees was performed before and 1, 7, 30 and 180 days after intra-articular methylpredn......The effect of temporary inflammatory suppression on synovial membrane enhancement, as determined by dynamic and static gadolinium-DTPA enhanced magnetic resonance imaging (MRI), was studied. MRI of 18 arthritic knees was performed before and 1, 7, 30 and 180 days after intra...

  12. Growth, characterization and dielectric studies of gadolinium ...

    Indian Academy of Sciences (India)

    solution of higher pH. After complete gelation, an .... between the gadolinium and fumarate ions because at higher ..... Department of Higher Education, Government of Jammu and. Kashmir, for providing and facilitating the teacher fellowship.

  13. Overview of current chelation practices

    Directory of Open Access Journals (Sweden)

    Y. Aydinok

    2011-12-01

    Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

  14. Simple method for quantification of gadolinium magnetic resonance imaging contrast agents using ESR spectroscopy.

    Science.gov (United States)

    Takeshita, Keizo; Kinoshita, Shota; Okazaki, Shoko

    2012-01-01

    To develop an estimation method of gadolinium magnetic resonance imaging (MRI) contrast agents, the effect of concentration of Gd compounds on the ESR spectrum of nitroxyl radical was examined. A solution of either 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPONE) or 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) was mixed with a solution of Gd compound and the ESR spectrum was recorded. Increased concentration of gadolinium-diethylenetriamine pentaacetic acid chelate (Gd-DTPA), an MRI contrast agent, increased the peak-to-peak line widths of ESR spectra of the nitroxyl radicals, in accordance with a decrease of their signal heights. A linear relationship was observed between concentration of Gd-DTPA and line width of ESR signal, up to approximately 50 mmol/L Gd-DTPA, with a high correlation coefficient. Response of TEMPONE was 1.4-times higher than that of TEMPOL as evaluated from the slopes of the lines. The response was slightly different among Gd compounds; the slopes of calibration curves for acua[N,N-bis[2-[(carboxymethyl)[(methylcarbamoyl)methyl]amino]ethyl]glycinato(3-)]gadolinium hydrate (Gd-DTPA-BMA) (6.22 μT·L/mmol) and gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelate (Gd-DOTA) (6.62 μT·L/mmol) were steeper than the slope for Gd-DTPA (5.45 μT·L/mmol), whereas the slope for gadolinium chloride (4.94 μT·L/mmol) was less steep than that for Gd-DTPA. This method is simple to apply. The results indicate that this method is useful for rough estimation of the concentration of Gd contrast agents if calibration is carried out with each standard compound. It was also found that the plot of the reciprocal square root of signal height against concentrations of contrast agents could be useful for the estimation if a constant volume of sample solution is taken and measured at the same position in the ESR cavity every time.

  15. Manganese(II) chelate contrast media

    International Nuclear Information System (INIS)

    Rocklage, S.M.; Quay, S.C.

    1994-01-01

    New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

  16. Gadolinium contrast-enhanced MRI sequence does not have an incremental value in the assessment of sacroiliitis in patients with early inflammatory back pain by using MRI in combination with pelvic radiographs: a 2-year follow-up study

    NARCIS (Netherlands)

    van Onna, M.; van Tubergen, A.; van der Heijde, D.; Jurik, A. G.; Landewé, R.

    2014-01-01

    To evaluate the potential incremental value in detecting sacroiliitis of the T1 post-gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA) MRI sequence of the sacroiliac joints (SIJ) compared with the combination of short tau inversion recovery (STIR) MRI sequence and pelvic radiographs in

  17. Dynamic gadolinium-enhanced magnetic resonance imaging allows accurate assessment of the synovial inflammatory activity in rheumatoid arthritis knee joints: a comparison with synovial histology

    DEFF Research Database (Denmark)

    Axelsen, Mette Bjørndal; Stoltenberg, M.; Poggenborg, R.

    2012-01-01

    , the average grade of histological synovial inflammation was determined from four biopsies obtained during surgery. A preoperative series of T(1)-weighted dynamic fast low-angle shot (FLASH) MR images was obtained. Parameters characterizing contrast uptake dynamics, including the initial rate of enhancement...... capsule of the knee joint (Precise ROI). Intra- and interreader agreement was assessed using the intra-class correlation coefficient (ICC). Results: The IRE from the Quick ROI and the Precise ROI revealed high correlations to the grade of histological inflammation (Spearman's correlation coefficient (rho......) = 0.70, p = 0.001 and rho = 0.74, p = 0.001, respectively). Intraand inter-reader ICCs were very high (0.93-1.00). No Whole slice parameters were correlated to histology. Conclusion: DCE-MRI provides fast and accurate assessment of synovial inflammation in RA patients. Manual outlining of the joint...

  18. Effect of high-dose oral multivitamins and minerals in participants not treated with statins in the randomized Trial to Assess Chelation Therapy (TACT).

    Science.gov (United States)

    Issa, Omar M; Roberts, Rhonda; Mark, Daniel B; Boineau, Robin; Goertz, Christine; Rosenberg, Yves; Lewis, Eldrin F; Guarneri, Erminia; Drisko, Jeanne; Magaziner, Allan; Lee, Kerry L; Lamas, Gervasio A

    2018-01-01

    In a prespecified subgroup analysis of participants not on statin therapy at baseline in the TACT, a high-dose complex oral multivitamins and multimineral regimen was found to have a large unexpected benefit compared with placebo. The regimen tested was substantially different from any vitamin regimen tested in prior clinical trials. To explore these results, we performed detailed additional analyses of participants not on statins at enrollment in TACT. TACT was a factorial trial testing chelation treatments and a 28-component high-dose oral multivitamins and multiminerals regimen versus placebo in post-myocardial infarction (MI) patients 50 years or older. There were 460 (27%) of 1,708 TACT participants not taking statins at baseline, 224 (49%) were in the active vitamin group and 236 (51%) were in the placebo group. Patients were enrolled at 134 sites around the United States and Canada. Daily high-dose oral multivitamins and multiminerals (6 tablets, active or placebo). The primary end point of TACT was time to the first occurrence of any component of the composite end point: all-cause mortality, MI, stroke, coronary revascularization, or hospitalization for angina. The primary end point occurred in 137 nonstatin participants (30%), of which 51 (23%) of 224 were in the active group and 86 (36%) of 236 were taking placebo (hazard ratio, 0.62; 95% confidence interval, 0.44-0.87; P=.006). Results in the key TACT secondary end point, a combination of cardiovascular mortality, stroke, or recurrent MI, was consistent in favoring the active vitamin group (hazard ratio, 0.46; 95% confidence interval, 0.28-0.75; P=.002). Multiple end point analyses were consistent with these results. High-dose oral multivitamin and multimineral supplementation seem to decrease combined cardiac events in a stable, post-MI population not taking statin therapy at baseline. These unexpected findings are being retested in the ongoing TACT2. Copyright © 2017 The Authors. Published by Elsevier

  19. Highly stabilized gadolinium chelates functionalized on metal nanoparticles as magnetic resonance imaging contrast agent

    Science.gov (United States)

    Siddiqui, Talha S.

    Magnetic resonance imaging (MRI) is a non-invasive method for imaging and diagnosing tissue damage, organ function and the vascular system. Magnevist(TM) a complex of diethylenetriaminepentaacetic acid (DTPA) and Gd3+ is a clinically approved contrast agent for MRI. A derivative of DTPA was formed by the addition of two cysteine groups (DTPA-L-Cys) through amide linkage. The Gd complex of this ligand bonds with the silver surfaces through the cysteine thiols. GdDTPA-L-Cys was bound to ˜10nm diameter Ag nanoparticles for use as a multifunctional MRI contrast agent. The ligand and complex were characterized by 1H and 13C NMR, ESI-MS and IR spectroscopy. The silver construct was characterized by TEM, TGA and UV-Vis absorption spectra. The per metal complex r1 relaxivity of GdDTPA-L-Cys{Ag} greater than that of Magnavist(TM) with the same molarity for both compounds. The synthesis of a DTPA derivative is described that allows it to bind to silver or gold nanoparticles through a single thiol linkage (DTPASH). The resulting Gd complex, GdDTPASH, was bound to Ag nanoparticles to create a single monolayer on the surface. The construct was further stabilized in buffered solution with the addition of a thiolated PEG chain. The highly stabilized nanoparticle construct delivers a high payload of Gd compelex and is an effective T1 brightening agent. The production of this type of construct opens the way for engineered multimodal MRI contrast agents.

  20. Antioxidant, Iron-chelating and Anti-glucosidase Activities of Typha ...

    African Journals Online (AJOL)

    Iron chelating activity was assessed using a ferrozine-based assay. Anti- glucosidase activity was determined using 4-nitrophenyl ... flavonoid (TF) content was determined based an aluminum chloride colorimetric assay [6]. TF content was ..... Dietary iron restriction or iron chelation protects from diabetes and loss of β-cell.

  1. The influence of functional groups on the permeation and distribution of antimycobacterial rhodamine chelators.

    Science.gov (United States)

    Moniz, T; Leite, A; Silva, T; Gameiro, P; Gomes, M S; de Castro, B; Rangel, M

    2017-10-01

    We formerly hypothesized a mechanism whereby the antimycobacterial efficiency of a set of rhodamine labelled iron chelators is improved via the rhodamine fluorophore which enhances the chelators' permeation properties through membranes. To validate our hypothesis in a cellular context and to understand the influence of the structure of the fluorophore on the chelator's uptake and distribution within macrophages we now report comparative confocal microscopy studies performed with a set of rhodamine labelled chelators. We identify the functional groups of the chelator's framework that favor uptake by macrophages and conclude that the antimycobacterial effect is strongly related with the capacity of the chelator to distribute within the host cell and its compartments, a property that is closely related with the chelators' ability to interact with membranes. The quantification of the chelators' interaction with membranes was assessed through measurement of the corresponding partition constants in liposomes. The overall results support that the compounds which are preferentially taken up are the most efficient antimycobacterial chelators and for that reason we infer that the biological activity is modulated by the structural features of the fluorophore. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Chelation therapy to prevent diabetes-associated cardiovascular events.

    Science.gov (United States)

    Diaz, Denisse; Fonseca, Vivian; Aude, Yamil W; Lamas, Gervasio A

    2018-05-24

    For over 60 years, chelation therapy with disodium ethylene diamine tetraacetic acid (EDTA, edetate) had been used for the treatment of cardiovascular disease (CVD) despite lack of scientific evidence for efficacy and safety. The Trial to Assess Chelation Therapy (TACT) was developed and received funding from the National Institutes of Health (NIH) to ascertain the safety and efficacy of chelation therapy in patients with CVD. This pivotal trial demonstrated an improvement in outcomes in postmyocardial infarction (MI) patients. Interestingly, it also showed a particularly large reduction in CVD events and all-cause mortality in the prespecified subgroup of patients with diabetes. The TACT results may support the concept of metal chelation to reduce metal-catalyzed oxidation reactions that promote the formation of advanced glycation end products, a precursor of diabetic atherosclerosis. In this review, we summarize the epidemiological and basic evidence linking toxic metal accumulation and diabetes-related CVD, supported by the salutary effects of chelation in TACT. If the ongoing NIH-funded TACT2, in diabetic post-MI patients, proves positive, this unique therapy will enter the armamentarium of endocrinologists and cardiologists seeking to reduce the atherosclerotic risk of their diabetic patients.

  3. Are gadolinium contrast agents suitable for gadolinium neutron capture therapy?

    Science.gov (United States)

    De Stasio, Gelsomina; Rajesh, Deepika; Casalbore, Patrizia; Daniels, Matthew J; Erhardt, Robert J; Frazer, Bradley H; Wiese, Lisa M; Richter, Katherine L; Sonderegger, Brandon R; Gilbert, Benjamin; Schaub, Sebastien; Cannara, Rachel J; Crawford, John F; Gilles, Mary K; Tyliszczak, Tolek; Fowler, John F; Larocca, Luigi M; Howard, Steven P; Mercanti, Delio; Mehta, Minesh P; Pallini, Roberto

    2005-06-01

    Gadolinium neutron capture therapy (GdNCT) is a potential treatment for malignant tumors based on two steps: (1) injection of a tumor-specific (157)Gd compound; (2) tumor irradiation with thermal neutrons. The GdNC reaction can induce cell death provided that Gd is proximate to DNA. Here, we studied the nuclear uptake of Gd by glioblastoma (GBM) tumor cells after treatment with two Gd compounds commonly used for magnetic resonance imaging, to evaluate their potential as GdNCT agents. Using synchrotron X-ray spectromicroscopy, we analyzed the Gd distribution at the subcellular level in: (1) human cultured GBM cells exposed to Gd-DTPA or Gd-DOTA for 0-72 hours; (2) intracerebrally implanted C6 glioma tumors in rats injected with one or two doses of Gd-DOTA, and (3) tumor samples from GBM patients injected with Gd-DTPA. In cell cultures, Gd-DTPA and Gd-DOTA were found in 84% and 56% of the cell nuclei, respectively. In rat tumors, Gd penetrated the nuclei of 47% and 85% of the tumor cells, after single and double injection of Gd-DOTA, respectively. In contrast, in human GBM tumors 6.1% of the cell nuclei contained Gd-DTPA. Efficacy of Gd-DTPA and Gd-DOTA as GdNCT agents is predicted to be low, due to the insufficient number of tumor cell nuclei incorporating Gd. Although multiple administration schedules in vivo might induce Gd penetration into more tumor cell nuclei, a search for new Gd compounds with higher nuclear affinity is warranted before planning GdNCT in animal models or clinical trials.

  4. Chelators for investigating zinc metalloneurochemistry

    OpenAIRE

    Radford, Robert John; Lippard, Stephen J.

    2013-01-01

    The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals o...

  5. Optimal gadolinium dose level for magnetic resonance imaging (MRI) contrast enhancement of U87-derived tumors in athymic nude rats for the assessment of photodynamic therapy

    Science.gov (United States)

    Cross, Nathan; Varghai, Davood; Flask, Chris A.; Feyes, Denise K.; Oleinick, Nancy L.; Dean, David

    2009-02-01

    This study aims to determine the effect of varying gadopentetate dimeglumine (Gd-DTPA) dose on Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) tracking of brain tumor photodynamic therapy (PDT) outcome. Methods: We injected 2.5 x 105 U87 cells (derived from human malignant glioma) into the brains of six athymic nude rats. After 9, 12, and 13 days DCE-MRI images were acquired on a 9.4 T micro-MRI scanner before and after administration of 100, 150, or 200 μL of Gd-DTPA. Results: Tumor region normalized DCE-MRI scan enhancement at peak was: 1.217 over baseline (0.018 Standard Error [SE]) at the 100 μL dose, 1.339 (0.013 SE) at the 150 μL dose, and 1.287 (0.014 SE) at the 200 μL dose. DCE-MRI peak tumor enhancement at the 150 μL dose was significantly greater than both the 100 μL dose (p DTPA dose provided the greatest T1 weighted contrast enhancement, while minimizing negative T2* effects, in DCE-MRI scans of U87-derived tumors. Maximizing Gd-DTPA enhancement in DCE-MRI scans may assist development of a clinically robust (i.e., unambiguous) technique for PDT outcome assessment.

  6. Bone marrow and chelatable iron in patients with protein energy ...

    African Journals Online (AJOL)

    Objectives: To examine the iron status of malnourished children by comparing bone marrow iron deposits in children with protein energy malnutrition with those in well-nourished controls, and measuring chelatable urinary iron excretion in children with kwashiorkor. Design: Bone marrow iron was assessed histologicaHy in ...

  7. Room temperature ferromagnetic gadolinium silicide nanoparticles

    Science.gov (United States)

    Hadimani, Magundappa Ravi L.; Gupta, Shalabh; Harstad, Shane; Pecharsky, Vitalij; Jiles, David C.

    2018-03-06

    A particle usable as T1 and T2 contrast agents is provided. The particle is a gadolinium silicide (Gd5Si4) particle that is ferromagnetic at temperatures up to 290 K and is less than 2 .mu.m in diameter. An MRI contrast agent that includes a plurality of gadolinium silicide (Gd.sub.5Si.sub.4) particles that are less than 1 .mu.m in diameter is also provided. A method for creating gadolinium silicide (Gd5Si4) particles is also provided. The method includes the steps of providing a Gd5Si4 bulk alloy; grinding the Gd5Si4 bulk alloy into a powder; and milling the Gd5Si4 bulk alloy powder for a time of approximately 20 minutes or less.

  8. Gadolinium-based Contrast Media, Cerebrospinal Fluid and the Glymphatic System: Possible Mechanisms for the Deposition of Gadolinium in the Brain.

    Science.gov (United States)

    Taoka, Toshiaki; Naganawa, Shinji

    2018-04-10

    After Kanda's first report in 2014 on gadolinium (Gd) deposition in brain tissue, a considerable number of studies have investigated the explanation for the observation. Gd deposition in brain tissue after repeated administration of gadolinium-based contrast medium (GBCM) has been histologically proven, and chelate stability has been shown to affect the deposition. However, the mechanism for this deposition has not been fully elucidated. Recently, a hypothesis was introduced that involves the 'glymphatic system', which is a coined word that combines 'gl' for glia cell and 'lymphatic' system. According to this hypothesis, the perivascular space functions as a conduit for cerebrospinal fluid to flow into the brain parenchyma. The perivascular space around the arteries allows cerebrospinal fluid to enter the interstitial space of the brain tissue through water channels controlled by aquaporin 4. The cerebrospinal fluid entering the interstitial space clears waste proteins from the tissue. It then flows into the perivascular space around the vein and is discharged outside the brain. In addition to the hypothesis regarding the glymphatic system, some reports have described that after GBCM administration, some of the GBCM distributes through systemic blood circulation and remains in other compartments including the cerebrospinal fluid. It is thought that the GBCM distributed into the cerebrospinal fluid cavity via the glymphatic system may remain in brain tissue for a longer duration compared to the GBCM in systemic circulation. Glymphatic system may of course act as a clearance system for GBCM from brain tissue. Based on these findings, the mechanism for Gd deposition in the brain will be discussed in this review. The authors speculate that the glymphatic system may be the major contributory factor to the deposition and clearance of gadolinium in brain tissue.

  9. EDTA chelation therapy for cardiovascular disease: a systematic review

    Directory of Open Access Journals (Sweden)

    Wu Ping

    2005-11-01

    Full Text Available Abstract Background Numerous practitioners of both conventional and complementary and alternative medicine throughout North America and Europe claim that chelation therapy with EDTA is an effective means to both control and treat cardiovascular disease. These claims are controversial, and several randomized controlled trials have been completed dealing with this topic. To address this issue we conducted a systematic review to evaluate the best available evidence for the use of EDTA chelation therapy in the treatment of cardiovascular disease. Methods We conducted a systematic review of 7 databases from inception to May 2005. Hand searches were conducted in review articles and in any of the trials found. Experts in the field were contacted and registries of clinical trials were searched for unpublished data. To be included in the final systematic review, the studies had to be randomized controlled clinical trials. Results A total of seven articles were found assessing EDTA chelation for the treatment of cardiovascular disease. Two of these articles were subgroup analyses of one RCT that looked at different clinical outcomes. Of the remaining five studies, two smaller studies found a beneficial effect whereas the other three exhibited no benefit for cardiovascular disease from the use of EDTA chelation therapy. Adverse effects were rare but those of note included a few cases of hypocalcemia and a single case of increased creatinine in a patient on the EDTA intervention. Conclusion The best available evidence does not support the therapeutic use of EDTA chelation therapy in the treatment of cardiovascular disease. Although not considered to be a highly invasive or harmful therapy, it is possible that the use of EDTA chelation therapy in lieu of proven therapy may result in causing indirect harm to the patient.

  10. Gadolinium-DTPA-enhanced magnetic resonance imaging of musculoskeletal infectious processes

    International Nuclear Information System (INIS)

    Hopkins, K.L.; Li, K.C.P.; Bergman, G.

    1995-01-01

    The purpose of this study was to assess whether gadolinium-enhanced magnetic resonance imaging (MRI) provides diagnostic information beyond that given by nonenhanced imaging in the evaluation of musculoskeletal infectious processes and whether it can be used for differentiating infectious from noninfectious inflammatory lesions. Magnetic resonance images performed with and without intravenous gadolinium-DTPA in 34 cases in which musculoskeletal infection had been clinically suspected were reviewed. Infectious lesions-including osteomyelitis, pyarthrosis, abscess, and cellulitis-were confirmed in a total of 22 cases: in 15 by biopsy or drainage and in 7 by clinical course. Our results show that gadolinium-DTPA-enhanced MRI is a highly sensitive technique in diagnosing musculoskeletal infectious lesions. It is especially useful in distinguishing abscesses from surrounding cellulitis/myositis. Lack of contrast enhancement rules out infection with a high degree of certainty. However, contrast enhancement cannot be used to reliably distinguish infectious from noninfectious inflammatory conditions. (orig.)

  11. Gadolinium-DTPA-enhanced magnetic resonance imaging of musculoskeletal infectious processes

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, K.L. [Dept. of Diagnostic Radiology, Stanford Univ. Medical Center, CA (United States); Li, K.C.P. [Dept. of Diagnostic Radiology, Stanford Univ. Medical Center, CA (United States); Bergman, G. [Dept. of Diagnostic Radiology, Stanford Univ. Medical Center, CA (United States)

    1995-07-01

    The purpose of this study was to assess whether gadolinium-enhanced magnetic resonance imaging (MRI) provides diagnostic information beyond that given by nonenhanced imaging in the evaluation of musculoskeletal infectious processes and whether it can be used for differentiating infectious from noninfectious inflammatory lesions. Magnetic resonance images performed with and without intravenous gadolinium-DTPA in 34 cases in which musculoskeletal infection had been clinically suspected were reviewed. Infectious lesions-including osteomyelitis, pyarthrosis, abscess, and cellulitis-were confirmed in a total of 22 cases: in 15 by biopsy or drainage and in 7 by clinical course. Our results show that gadolinium-DTPA-enhanced MRI is a highly sensitive technique in diagnosing musculoskeletal infectious lesions. It is especially useful in distinguishing abscesses from surrounding cellulitis/myositis. Lack of contrast enhancement rules out infection with a high degree of certainty. However, contrast enhancement cannot be used to reliably distinguish infectious from noninfectious inflammatory conditions. (orig.)

  12. Comparison of predicted with observed biokinetics of inhaled plutonium nitrate and gadolinium oxide in humans

    International Nuclear Information System (INIS)

    Hodgson, A.; Shutt, A.L.; Etherington, G.; Hodgson, S.A.; Rance, E.; Stradling, G.N.; Youngman, M.J.; Ziesenis, A.; Kreyling, W.G.

    2003-01-01

    The absorption kinetics to blood of plutonium and gadolinium after inhalation as nitrate and oxide in humans and animals has been studied. For each material, values describing the time dependence of absorption were derived from the studies in animals and used with the ICRP human respiratory tract model to predict lung retention and cumulative amounts to blood for the volunteers inhaling the same materials. Comparison with the observed behaviour in the volunteers suggests that absorption of plutonium and gadolinium is reasonably species independent, and that data obtained from animal studies can be used to assess their biokinetic behaviour in humans. (author)

  13. Growth, characterization and dielectric studies of gadolinium ...

    Indian Academy of Sciences (India)

    nitrogen atmosphere leads to the formation of gadolinium oxide as the final product. ... from Chengdu Haoxuan Technology Co. Ltd, China ..... by metal cations. A band centered at 1534.78 cm. −1 is due to asymmetric stretching of coordinated carboxylate group vas(COO. −. ). Another absorption band at 1398.38 cm. −1 is.

  14. Added diagnostic value of T2-weighted MR imaging to gadolinium-enhanced three-dimensional dynamic MR imaging for the detection of small hepatocellular carcinomas

    International Nuclear Information System (INIS)

    Kim, Young Kon; Lee, Young Hwan; Kim, Chong Soo; Han, Young Min

    2008-01-01

    Purpose: To assess the added value of T2-weighted MRI to gadolinium-enhanced dynamic MRI for detection of HCCs. Materials and methods: Two readers retrospectively analyzed MRIs of 115 patients with 131 HCCs (size; 0.6-2.0 cm) that had been diagnosed by histology (n = 41) or imaging findings (n = 90). Two separate blind image analyses of the gadolinium set and the combined T2-weighted imaging and gadolinium sets were performed. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method with four-point scale. Sensitivity and positive predictive value were also calculated. Results: For both observers, the Az values and sensitivities with the combined T2-weighed imaging and gadolinium set (mean Az 0.806, sensitivity 84.7) were significantly higher than those with the gadolinium set (mean Az 0.660, sensitivity 59.9) (p < 0.05). The addition of T2-weighted imaging led to a change in diagnosis for 27 lesions by both observers, which at gadolinium set were assigned a confidence level of 1 or 2 but at additional reading of T2-weighted imaging were assigned a confidence level of 3 or 4. For the positive predictive values, each image set showed a similar value for each observer. Conclusion: The addition of T2-weighted imaging to gadolinium-enhanced 3D dynamic imaging could be helpful in the detection of HCC by increasing reader confidence for HCCs with equivocal findings on gadolinium-enhanced MRIs

  15. Subcellular SIMS imaging of gadolinium isotopes in human glioblastoma cells treated with a gadolinium containing MRI agent

    Science.gov (United States)

    Smith, Duane R.; Lorey, Daniel R.; Chandra, Subhash

    2004-06-01

    Neutron capture therapy is an experimental binary radiotherapeutic modality for the treatment of brain tumors such as glioblastoma multiforme. Recently, neutron capture therapy with gadolinium-157 has gained attention, and techniques for studying the subcellular distribution of gadolinium-157 are needed. In this preliminary study, we have been able to image the subcellular distribution of gadolinium-157, as well as the other six naturally abundant isotopes of gadolinium, with SIMS ion microscopy. T98G human glioblastoma cells were treated for 24 h with 25 mg/ml of the metal ion complex diethylenetriaminepentaacetic acid Gd(III) dihydrogen salt hydrate (Gd-DTPA). Gd-DTPA is a contrast enhancing agent used for MRI of brain tumors, blood-brain barrier impairment, diseases of the central nervous system, etc. A highly heterogeneous subcellular distribution was observed for gadolinium-157. The nuclei in each cell were distinctly lower in gadolinium-157 than in the cytoplasm. Even within the cytoplasm the gadolinium-157 was heterogeneously distributed. The other six naturally abundant isotopes of gadolinium were imaged from the same cells and exhibited a subcellular distribution consistent with that observed for gadolinium-157. These observations indicate that SIMS ion microscopy may be a viable approach for subcellular studies of gadolinium containing neutron capture therapy drugs and may even play a major role in the development and validation of new gadolinium contrast enhancing agents for diagnostic MRI applications.

  16. Application of extracellular gadolinium-based MRI contrast agents and the risk of nephrogenic systemic fibrosis; Anwendung von extrazellulaeren gadoliniumhaltigen MR-Kontrastmitteln und Risiko der Nephrogenen Systemischen Fibrose

    Energy Technology Data Exchange (ETDEWEB)

    Heverhagen, J.T. [Univ. Hospital Bern (Switzerland). Inst. of Diagnostic, Interventional and Pediatric Radiology, Inselspital; Krombach, G.A. [Justus Liebig Univ. Hopsital Giessen (Germany). Diagnostic and Interventional Radiology; Gizewski, E. [Medical Univ. Innsbruck (Austria). Dept. of Neuroradiology

    2014-07-15

    Nephrogenic systemic fibrosis (NSF) is a serious, sometimes fatal disease. Findings in recent years have shown that a causal association between gadolinium containing contrast media and NSF is most likely. Therefore, the regulatory authorities have issued guidelines on the use of gadolinium-containing contrast media which have reduced the number of new cases of NSF to almost zero. However, it is for precisely this reason that the greatest care must still be taken to ensure that these guidelines are complied with. The most important factors are renal function, the quantity of gadolinium administered and coexisting diseases such as inflammation. All of these factors crucially influence the quantity of gadolinium released from the chelat in the body. This free gadolinium is thought to be the trigger for NSF. Other important factors are the stability of the gadolinium complex and furthermore the route of its elimination from the body. Partial elimination via the liver might be an additional protective mechanism. In conclusion, despite the NSF risk, contrast-enhanced MRI is a safe diagnostic procedure which can be used reliably and safely even in patients with severe renal failure, and does not necessarily have to be replaced by other methods.

  17. Gadolinium Deposition in Human Brain Tissues after Contrast-enhanced MR Imaging in Adult Patients without Intracranial Abnormalities.

    Science.gov (United States)

    McDonald, Robert J; McDonald, Jennifer S; Kallmes, David F; Jentoft, Mark E; Paolini, Michael A; Murray, David L; Williamson, Eric E; Eckel, Laurence J

    2017-11-01

    Purpose To determine whether gadolinium deposits in neural tissues of patients with intracranial abnormalities following intravenous gadolinium-based contrast agent (GBCA) exposure might be related to blood-brain barrier integrity by studying adult patients with normal brain pathologic characteristics. Materials and Methods After obtaining antemortem consent and institutional review board approval, the authors compared postmortem neuronal tissue samples from five patients who had undergone four to 18 gadolinium-enhanced magnetic resonance (MR) examinations between 2005 and 2014 (contrast group) with samples from 10 gadolinium-naive patients who had undergone at least one MR examination during their lifetime (control group). All patients in the contrast group had received gadodiamide. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy with energy-dispersive x-ray spectroscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Results Tissues from the four neuroanatomic regions of gadodiamide-exposed patients contained 0.1-19.4 μg of gadolinium per gram of tissue in a statistically significant dose-dependent relationship (globus pallidus: ρ = 0.90, P = .04). In contradistinction, patients in the control group had undetectable levels of gadolinium with ICP-MS. All patients had normal brain pathologic characteristics at autopsy. Three patients in the contrast group had borderline renal function (estimated glomerular filtration rate the contrast group was localized to the capillary endothelium and neuronal interstitium and, in two cases, within the nucleus of the cell. Conclusion Gadolinium deposition in neural tissues after GBCA administration occurs in the absence of intracranial abnormalities that might affect the permeability of the blood-brain barrier. These findings

  18. Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hamersvelt, Robbert W. van; Willemink, Martin J.; Jong, Pim A. de; Schilham, Arnold M.R.; Leiner, Tim [University Medical Center Utrecht, Department of Radiology, P.O. Box 85500, Utrecht (Netherlands); Milles, Julien [CT Clinical Science, Philips HealthCare, Best (Netherlands); Vlassenbroek, Alain [CT Clinical Science, Philips HealthCare, Brussels (Belgium)

    2017-09-15

    The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P < 0.001; ICCs > 0.99, CI 0.99-1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. (orig.)

  19. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

  20. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    International Nuclear Information System (INIS)

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

  1. Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

    Science.gov (United States)

    Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

    2007-12-01

    Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

  2. Studies on gadolinium precipitation in moderator system of nuclear reactor

    International Nuclear Information System (INIS)

    Joshi, Akhilesh C.; Rajesh, Puspalata; Rufus, A.L.; Velmurugan, S.

    2015-01-01

    Gadolinium is used in the moderator system of many Pressurised Heavy Water Reactors (PHWRs) for start-up, shut-down and reactivity control during operation. It is very much essential to maintain gadolinium concentration in the system as desired. It has been reported that gadolinium gets precipitated in as oxalate in carbonated water under the influence of γ-radiation. Hence, studies were carried out to investigate the effect of dose, presence of other metal ions and metal surfaces on the precipitation of gadolinium. The results showed that the amount of carboxylic acids viz., formic acid and oxalic acid, formed due to radiolysis is dependent on the dose and that the curve passes though a maxima. Gadolinium is added in higher concentration in Advanced Heavy Water Reactor. So, experiments with high concentration of gadolinium were also carried out. Ultra pure water saturated with high purity CO 2 containing gadolinium and desired ion/surface was irradiated with γ-radiation from 60 Co source at 25°C to doses ranging from 2.5-16.6 Mrad. At lower doses, formation of carboxylic acids takes place but as the dose increases, decomposition of these acids starts and hence the concentration Vs dose passes through a maximum. It was found that precipitation of gadolinium as oxalate occurred at lower doses. At higher doses, it was seen that pH of the solution decreases and hence solubility of gadolinium oxalate increases. It was also observed that the amount of gadolinium precipitated varied linearly with the initial concentration of gadolinium varying from 2 ppm to 20 ppm. While for gadolinium concentration from 20 ppm to 400 ppm, gadolinium in particulate form was observed. The amount of carboxylic acids formed depends on the nature of cations present in solution. It was found that the amount of oxalic acid formed in the case of gadolinium was more than that formed in the case of sodium. Presence of metal oxides such as ZrO 2 formed over zircoloy surfaces was found to

  3. f-Element Ion Chelation in Highly Basic Media

    International Nuclear Information System (INIS)

    Paine, R.T.

    2000-01-01

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelators for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  4. Contrast effects of a gadolinium filter

    International Nuclear Information System (INIS)

    Burgess, A.E.

    1981-01-01

    Several authors have suggested using heavy metal filters with K edges in the diagnostic energy range to reduce the width of the x-ray spectrum and hence reduce patient radiation exposure. This spectral narrowing also increases subject contrast and permits an increase in tube potential. Results of contrast measurements are presented for a 250 mu gadolinium filter. It was found that aluminum filter contrast could be matched by using 8 to 10 kVp higher potential with the gadolinium filter. Similar results were found for calcium tungstate and rare-earth screens. Measurements were also done to determine skin exposure and mAs ratios for both constant contrast and constant kVp technique conversion methods. A simple theory with one adjustable parameter gives a reasonable fit to the experimental results

  5. Isotope shift studies in gadolinium spectra

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Saksena, G.D.; Venugopalan, A.

    1976-01-01

    Isotope shift studies have been carried out in the gadolinium spectrum using a recording Fabry-Perot spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. Isotope shifts Δsigma(156-160) have been recorded in 134 lines in the region 3930-4140 A. Some of these lines involve the recently identified even configuration 4f 8 5d6s of Gd I and the newly classified transition 4f 8 6s-4f 8 6p of Gd II. From the isotope shift measurements of lines involving the 4f 8 6s-4f 8 6p transition in Gd II, the isotope shift, ΔT(156-160)=87 mK, has been obtained for the 4f 8 6s configuration. Electronic configurations have been suggested for a number of energy levels and configuration mixing has been pointed out in certain cases. (Auth.)

  6. The critical thermal expansion of gadolinium

    International Nuclear Information System (INIS)

    Robinson, K.; Lanchester, P.C.

    1978-01-01

    Measurements have been made of the critical thermal expansion of single crystals of gadolinium, prepared by solid state electrotransport processing. Although the expansion data can be fitted to a simple power law with exponents lambda + =-0.25, lambda - =-0.33, these values are not predicted by theory and a discontinuity remains at Tsub(c)=293.620 K. It is suggested that the results relate to a region of crossover to uniaxial dipolar behaviour. (Auth.)

  7. Light deflection in gadolinium molybdate ferroelastic crystals

    International Nuclear Information System (INIS)

    Staniorowski, Piotr; Bornarel, Jean

    2000-01-01

    The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle α i on the sample at room temperature. The A and B deflected beams do not cross each other during the α i variation, in contrast to results and calculations previously published. The model using the Fresnel equation confirms this result. The model presented is more accurate for numerical calculation than that using the Huygens construction. (author)

  8. Nephrogenic systemic fibrosis and gadolinium-based contrast media

    DEFF Research Database (Denmark)

    Thomsen, Henrik S; Morcos, Sameh K; Almén, Torsten

    2012-01-01

    PURPOSE: To update the guidelines of the Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) on nephrogenic systemic fibrosis and gadolinium-based contrast media. AREAS COVERED: Topics reviewed include the history, clinical features and prevalence of neph...... guidelines regarding gadolinium contrast agents minimises the risk of NSF • Potential long-term harm from gadolinium accumulation in the body is discussed.......PURPOSE: To update the guidelines of the Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) on nephrogenic systemic fibrosis and gadolinium-based contrast media. AREAS COVERED: Topics reviewed include the history, clinical features and prevalence...... of nephrogenic systemic fibrosis and the current understanding of its pathophysiology. The risk factors for NSF are discussed and prophylactic measures are recommended. The stability of the different gadolinium-based contrast media and the potential long-term effects of gadolinium in the body have also been...

  9. Room temperature ferromagnetic gadolinium silicide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hadimani, Magundappa Ravi L.; Gupta, Shalabh; Harstad, Shane; Pecharsky, Vitalij; Jiles, David C.

    2018-03-06

    A particle usable as T1 and T2 contrast agents is provided. The particle is a gadolinium silicide (Gd5Si4) particle that is ferromagnetic at temperatures up to 290 K and is less than 2 .mu.m in diameter. An MRI contrast agent that includes a plurality of gadolinium silicide (Gd.sub.5Si.sub.4) particles that are less than 1 .mu.m in diameter is also provided. A method for creating gadolinium silicide (Gd5Si4) particles is also provided. The method includes the steps of providing a Gd5Si4 bulk alloy; grinding the Gd5Si4 bulk alloy into a powder; and milling the Gd5Si4 bulk alloy powder for a time of approximately 20 minutes or less.

  10. Experimental and thermodynamic study of the erbium-oxygen-zirconium and gadolinium-oxygen-zirconium systems

    International Nuclear Information System (INIS)

    Jourdan, J.

    2009-11-01

    This work is a contribution to the development of innovative concepts for fuel cladding in pressurized water nuclear reactors. This concept implies the insertion of rare earth (erbium and gadolinium) in the zirconium fuel cladding. The determination of phase equilibria in the systems is essential prior to the implementation of such a promising solution. This study consisted in an experimental determination of the erbium-zirconium phase diagram. For this, we used many different techniques in order to obtain diagram data such as solubility limits, solidus, liquidus or invariant temperatures. These data allowed us to present a new diagram, very different from the previous one available in the literature. We also assessed the diagram using the CALPHAD approach. In the gadolinium-zirconium system, we determined experimentally the solubility limits. Those limits had never been determined before, and the values we obtained showed a very good agreement with the experimental and assessed versions of the diagram. Because these alloys are subjected to oxygen diffusion throughout their life, we focused our attention on the erbium-oxygen-zirconium and gadolinium-oxygen-zirconium systems. The first system has been investigated experimentally. The alloys fabrication has been performed using powder metallurgy. In order to obtain pure raw materials, we fabricated powder from erbium and zirconium bulk metals using hydrogen absorption/desorption. The characterisation of the ternary pellets allowed the determination of two ternary isothermal sections at 800 and 1100 C. For the gadolinium-oxygen-zirconium system, we calculated the phase equilibria at temperatures ranging from 800 to 1100 C, using a homemade database compiled from literature assessments of the oxygen-zirconium, gadolinium-zirconium and gadolinia-zirconia systems. Finally, we determined the mechanical properties, in connexion with the microstructure, of industrial quality alloys in order to identify the influence of

  11. Determination of gadolinium by the method of derivative spectrophotometry

    International Nuclear Information System (INIS)

    Aleksandrova, N.N.; Mishchenko, V.T.; Poluehktov, N.S.; Mukomel', V.L.

    1988-01-01

    Technique for gadolinium determination at the presence of interfering rare earth elements, which is based on the derivative spectrophotometry method, is suggested. The technique is of increased selectivity and allows to determine gadolinium in the mixtures with elements, which presence in solution makes impossible to determine gadolinium directly. At binary mixtures analysis Sr relative standard deviation does not exceed 0.03, while at the analysis of more complex mixtures Sr increases up to 0.06

  12. Calculation qualification of gadolinium burnable poisons in water reactors

    International Nuclear Information System (INIS)

    Chaucheprat, P.

    1988-01-01

    The work presented in this thesis constitutes the qualification on the one end of Appolo-Neptune scheme for the gadolinium burnable poison in a pressurized water reactor, and on the other end of basis nuclear data on natural gadolinium. This study has permitted to reduce by a factor 3 the actual incertitude on the gadolinium poison comparatively at precisions cited in international benchmarks calculations [fr

  13. High spatial resolution free-breathing 3D late gadolinium enhancement cardiac magnetic resonance imaging in ischaemic and non-ischaemic cardiomyopathy: quantitative assessment of scar mass and image quality.

    Science.gov (United States)

    Bizino, Maurice B; Tao, Qian; Amersfoort, Jacob; Siebelink, Hans-Marc J; van den Bogaard, Pieter J; van der Geest, Rob J; Lamb, Hildo J

    2018-04-06

    To compare breath-hold (BH) with navigated free-breathing (FB) 3D late gadolinium enhancement cardiac MRI (LGE-CMR) MATERIALS AND METHODS: Fifty-one patients were retrospectively included (34 ischaemic cardiomyopathy, 14 non-ischaemic cardiomyopathy, three discarded). BH and FB 3D phase sensitive inversion recovery sequences were performed at 3T. FB datasets were reformatted into normal resolution (FB-NR, 1.46x1.46x10mm) and high resolution (FB-HR, isotropic 0.91-mm voxels). Scar mass, scar edge sharpness (SES), SNR and CNR were compared using paired-samples t-test, Pearson correlation and Bland-Altman analysis. Scar mass was similar in BH and FB-NR (mean ± SD: 15.5±18.0 g vs. 15.5±16.9 g, p=0.997), with good correlation (r=0.953), and no bias (mean difference ± SD: 0.00±5.47 g). FB-NR significantly overestimated scar mass compared with FB-HR (15.5±16.9 g vs 14.4±15.6 g; p=0.007). FB-NR and FB-HR correlated well (r=0.988), but Bland-Altman demonstrated systematic bias (1.15±2.84 g). SES was similar in BH and FB-NR (p=0.947), but significantly higher in FB-HR than FB-NR (pFB-NR (pFB-HR than FB-NR (p<0.01). Navigated free-breathing 3D LGE-CMR allows reliable scar mass quantification comparable to breath-hold. During free-breathing, spatial resolution can be increased resulting in improved sharpness and reduced scar mass. • Navigated free-breathing 3D late gadolinium enhancement is reliable for myocardial scar quantification. • High-resolution 3D late gadolinium enhancement increases scar sharpness • Ischaemic and non-ischaemic cardiomyopathy patients can be imaged using free-breathing LGE CMR.

  14. Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates.

    Science.gov (United States)

    Nwe, K; Bernardo, M; Regino, C A S; Williams, M; Brechbiel, M W

    2010-08-15

    In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N',N',N'',N''-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex(R) G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1, respectively. Molar relaxivity measured at pH 7.4, 22 degrees C, and 3T are comparable (29.5 vs 26.9 mM(-1)s(-1)), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t(1/2)=16 vs 29 min). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties. Published by Elsevier Ltd.

  15. Phosphinic acid functionalized polyazacycloalkane chelators for radiodiagnostics and radiotherapeutics: unique characteristics and applications.

    Science.gov (United States)

    Notni, Johannes; Šimeček, Jakub; Wester, Hans-Jürgen

    2014-06-01

    Given the wide application of positron emission tomography (PET), positron-emitting metal radionuclides have received much attention recently. Of these, gallium-68 has become particularly popular, as it is the only PET nuclide commercially available from radionuclide generators, therefore allowing local production of PET radiotracers independent of an on-site cyclotron. Hence, interest in optimized bifunctional chelators for the elaboration of (68) Ga-labeled bioconjugates has been rekindled as well, resulting in the development of improved triazacyclononane-triphosphinate (TRAP) ligand structures. The most remarkable features of these ligands are unparalleled selectivity for Ga(III) , rapid Ga(III) complexation kinetics, extraordinarily high thermodynamic stability, and kinetic inertness of the respective Ga(III) chelates. As a result, TRAP chelators exhibit very favorable (68) Ga-labeling properties. Based on the scaffolds NOPO (1,4,7-triazacyclononane-1,4-bis[methylene(hydroxymethyl)phosphinic acid]-7-[methylene(2-carboxyethyl)phosphinic acid]) and TRAP-Pr, tailored for convenient preparation of (68) Ga-labeled monomeric and multimeric bioconjugates, a variety of novel (68) Ga radiopharmaceuticals have been synthesized. These include bisphosphonates, somatostatin receptor ligands, prostate-specific membrane antigen (PSMA)-targeting peptides, and cyclic RGD pentapeptides, for in vivo PET imaging of bone, neuroendocrine tumors, prostate cancer, and integrin expression, respectively. Furthermore, TRAP-based (68) Ga-labeled gadolinium(III) complexes have been proposed as bimodal probes for PET/MRI, and a cyclen-based analogue of TRAP-Pr has been suggested for the elaboration of targeted radiotherapeutics comprising radiolanthanide ions. Thus, polyazacycloalkane-based polyphosphinic acid chelators are a powerful toolbox for pharmaceutical research, particularly for the development of (68) Ga radiopharmaceuticals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Chelating agents in pharmacology, toxicology and therapeutics

    International Nuclear Information System (INIS)

    1988-01-01

    The proceedings contain 71 abstracts of papers. Fourteen abstracts were inputted in INIS. The topics covered include: the effects of chelating agents on the retention of 63 Ni, 109 Cd, 203 Hg, 144 Ce, 95 Nb and the excretion of 210 Po, 63 Ni, 48 V, 239 Pu, 241 Am, 54 Mn; the applications of tracer techniques for studies of the efficacy of chelation therapy in patients with heart and brain disorders; and the treatment of metal poisoning with chelating agents. (J.P.)

  17. Thermal diffusivity of samarium-gadolinium zirconate solid solutions

    International Nuclear Information System (INIS)

    Pan, W.; Wan, C.L.; Xu, Q.; Wang, J.D.; Qu, Z.X.

    2007-01-01

    We synthesized samarium-gadolinium zirconate solid solutions and determined their thermal diffusivities, Young's moduli and thermal expansion coefficients, which are very important for their application in thermal barrier coatings. Samarium-gadolinium zirconate solid solutions have extremely low thermal diffusivity between 20 and 600 deg. C. The solid solutions have lower Young's moduli and higher thermal expansion coefficients than those of pure samarium and gadolinium zirconates. This combination of characteristics is promising for the application of samarium and gadolinium zirconates in gas turbines. The mechanism of phonon scattering by point defects is discussed

  18. Contrast opacification for CT from iodine, gadolinium and ytterbium

    International Nuclear Information System (INIS)

    Zwicker, C.; Langer, M.; Ullrich, V.; Felix, R.

    1993-01-01

    The absorption of the elements iodine, gadolinium und ytterbium in various dilutions was studied in relation to CT. Regression analysis and specific CT density measurements showed that absorption decreases from gadolinium to ytterbium and iodine. These results were confirmed by experiments using ten dogs. Boli of 0.5 molar gadolinium used for angio-CT without table movement showed the largest increase in density in the aorta and liver with an average of 190 HU and 21 HU respectively compared with iodine which gave 157 HU and 12 HU respectively. The animal experimental studies suggest that gadolinium and ytterbium are suitable contrast media for dynamic CT investigations. (orig.) [de

  19. Iron overload of organism and current options of chelation treatment in onco haematology

    International Nuclear Information System (INIS)

    Guman, T.; Rothova, E.; Kafkova, A.; Fricova, M.; Dulova, I.; Stecova, N.; Hlebaskova, M.; Surova, M.; Takac, V.

    2011-01-01

    The article summarizes the biological importance of iron in the organism, primary and secondary causes of iron overload, complications in function of liver, heart and endocrine organs due to overload of iron, the pathophysiology of iron overload, transfusion risks associated with the iron overload, assessment of risk groups of patients suitable for chelation treatment fulfilling the indication criteria, treatment modalities of chelation therapy and its significance regarding the prevention and treatment effectiveness. (author)

  20. Accurate late gadolinium enhancement prediction by early T1- based quantitative synthetic mapping

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, Randy van; Harst, Pim van der [University of Groningen, University Medical Centre Groningen, Centre for Medical Imaging, Groningen (Netherlands); University of Groningen, University Medical Centre Groningen, Department of Cardiology, Groningen (Netherlands); Kuijpers, Dirkjan [University of Groningen, University Medical Centre Groningen, Centre for Medical Imaging, Groningen (Netherlands); Department of Cardiovascular Imaging HMC-Bronovo, The Hague (Netherlands); Kaandorp, Theodorus A.M.; Dijkman, Paul R.M. van [Department of Cardiovascular Imaging HMC-Bronovo, The Hague (Netherlands); Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Centre Groningen, Centre for Medical Imaging, Groningen (Netherlands); University Medical Center Groningen, Center for Medical Imaging, Groningen (Netherlands)

    2018-02-15

    Early synthetic gadolinium enhancement (ESGE) imaging from post-contrast T1 mapping after adenosine stress-perfusion cardiac magnetic resonance (CMR) was compared to conventional late gadolinium enhancement (LGE) imaging for assessing myocardial scar. Two hundred fourteen consecutive patients suspected of myocardial ischaemia were referred for stress-perfusion CMR. Myocardial infarct volume was quantified on a per-subsegment basis in both synthetic (2-3 min post-gadolinium) and conventional (9 min post-gadolinium) images by two independent observers. Sensitivity, specificity, PPV and NPV were calculated on a per-patient and per-subsegment basis. Both techniques detected 39 gadolinium enhancement areas in 23 patients. The median amount of scar was 2.0 (1.0-3.1) g in ESGE imaging and 2.2 (1.1-3.1) g in LGE imaging (p=0.39). Excellent correlation (r=0.997) and agreement (mean absolute difference: -0.028±0.289 ml) were found between ESGE and LGE images. Sensitivity, specificity, PPV and NPV of ESGE imaging were 96 (78.9-99.9), 99 (97.1-100.0)%, 96 (76.5-99.4) and 99.5 (96.6-99.9) in patient-based and 99 (94.5-100.0), 100 (99.9-100.0)%, 97.0 (91.3-99.0) and 100.0 (99.8-100.0) in subsegment-based analysis. ESGE based on post-contrast T1 mapping after adenosine stress-perfusion CMR imaging shows excellent agreement with conventional LGE imaging for assessing myocardial scar, and can substantially shorten clinical acquisition time. (orig.)

  1. Accurate late gadolinium enhancement prediction by early T1- based quantitative synthetic mapping

    International Nuclear Information System (INIS)

    Dijk, Randy van; Harst, Pim van der; Kuijpers, Dirkjan; Kaandorp, Theodorus A.M.; Dijkman, Paul R.M. van; Vliegenthart, Rozemarijn; Oudkerk, Matthijs

    2018-01-01

    Early synthetic gadolinium enhancement (ESGE) imaging from post-contrast T1 mapping after adenosine stress-perfusion cardiac magnetic resonance (CMR) was compared to conventional late gadolinium enhancement (LGE) imaging for assessing myocardial scar. Two hundred fourteen consecutive patients suspected of myocardial ischaemia were referred for stress-perfusion CMR. Myocardial infarct volume was quantified on a per-subsegment basis in both synthetic (2-3 min post-gadolinium) and conventional (9 min post-gadolinium) images by two independent observers. Sensitivity, specificity, PPV and NPV were calculated on a per-patient and per-subsegment basis. Both techniques detected 39 gadolinium enhancement areas in 23 patients. The median amount of scar was 2.0 (1.0-3.1) g in ESGE imaging and 2.2 (1.1-3.1) g in LGE imaging (p=0.39). Excellent correlation (r=0.997) and agreement (mean absolute difference: -0.028±0.289 ml) were found between ESGE and LGE images. Sensitivity, specificity, PPV and NPV of ESGE imaging were 96 (78.9-99.9), 99 (97.1-100.0)%, 96 (76.5-99.4) and 99.5 (96.6-99.9) in patient-based and 99 (94.5-100.0), 100 (99.9-100.0)%, 97.0 (91.3-99.0) and 100.0 (99.8-100.0) in subsegment-based analysis. ESGE based on post-contrast T1 mapping after adenosine stress-perfusion CMR imaging shows excellent agreement with conventional LGE imaging for assessing myocardial scar, and can substantially shorten clinical acquisition time. (orig.)

  2. Gadolinium deposition within the dentate nucleus and globus pallidus after repeated administrations of gadolinium-based contrast agents - current status

    Energy Technology Data Exchange (ETDEWEB)

    Stojanov, Dragan [University of Nis, Faculty of Medicine, Nis (Serbia); Center for Radiology, Nis (Serbia); Aracki-Trenkic, Aleksandra [Center for Radiology, Nis (Serbia); Benedeto-Stojanov, Daniela [University of Nis, Faculty of Medicine, Nis (Serbia)

    2016-05-15

    Gadolinium-based contrast agents (GBCAs) have been used clinically since 1988 for contrast-enhanced magnetic resonance imaging (CE-MRI). Generally, GBCAs are considered to have an excellent safety profile. However, GBCA administration has been associated with increased occurrence of nephrogenic systemic fibrosis (NSF) in patients with severely compromised renal function, and several studies have shown evidence of gadolinium deposition in specific brain structures, the globus pallidus and dentate nucleus, in patients with normal renal function. Gadolinium deposition in the brain following repeated CE-MRI scans has been demonstrated in patients using T1-weighted unenhanced MRI and inductively coupled plasma mass spectroscopy. Additionally, rodent studies with controlled GBCA administration also resulted in neural gadolinium deposits. Repeated GBCA use is associated with gadolinium deposition in the brain. This is especially true with the use of less-stable, linear GBCAs. In spite of increasing evidence of gadolinium deposits in the brains of patients after multiple GBCA administrations, the clinical significance of these deposits continues to be unclear. Here, we discuss the current state of scientific evidence surrounding gadolinium deposition in the brain following GBCA use, and the potential clinical significance of gadolinium deposition. There is considerable need for further research, both to understand the mechanism by which gadolinium deposition in the brain occurs and how it affects the patients in which it occurs. (orig.)

  3. Chelates for Micronutrient Nutrition among Crops

    Indian Academy of Sciences (India)

    years, it has been recognised that compounds containing che- lated metals could .... when using small amounts and no build up of harmful levels. ... degradation of iron chelates. .... down by soil microorganisms into much smaller units for ab-.

  4. MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

    Energy Technology Data Exchange (ETDEWEB)

    Abergel, Rebecca J.; Raymond, Kenneth N.

    2011-07-13

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  5. Radiopharmaceutical chelates and method of external imaging

    International Nuclear Information System (INIS)

    1976-01-01

    The preparation of the following chemicals is described: chelates of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The compounds described are suitable for intravenous injection, have an excellent in vivo stability and are good organ seekers. Tin(II) choride or other tin(II) compounds are used as chelating agents

  6. Cost and availability of gadolinium for nuclear fuel reprocessing plants

    International Nuclear Information System (INIS)

    Klepper, O.H.

    1985-06-01

    Gadolinium is currently planned for use as a soluble neutron poison in nuclear fuel reprocessing plants to prevent criticality of solutions of spent fuel. Gadolinium is relatively rare and expensive. The present study was undertaken therefore to estimate whether this material is likely to be available in quantities sufficient for fuel reprocessing and at reasonable prices. It was found that gadolinium, one of 16 rare earth elements, appears in the marketplace as a by-product and that its present supply is a function of the production rate of other more prevalent rare earths. The potential demand for gadolinium in a fuel reprocessing facility serving a future fast reactor industry amounts to only a small fraction of the supply. At the present rate of consumption, domestic supplies of rare earths containing gadolinium are adequate to meet national needs (including fuel reprocessing) for over 100 years. With access to foreign sources, US demands can be met well beyond the 21st century. It is concluded therefore that the supply of gadolinium will quite likely be more than adequate for reprocessing spent fuel for the early generation of fast reactors. The current price of 99.99% pure gadolinium oxide lies in the range $50/lb to $65/lb (1984 dollars). By the year 2020, in time for reprocessing spent fuel from an early generation of large fast reactors, the corresponding values are expected to lie in the $60/lb to $75/lb (1984 dollars) price range. This increase is modest and its economic impact on nuclear fuel reprocessing would be minor. The economic potential for recovering gadolinium from the wastes of nuclear fuel reprocessing plants (which use gadolinium neutron poison) was also investigated. The cost of recycled gadolinium was estimated at over twelve times the cost of fresh gadolinium, and thus recycle using current recovery technology is not economical. 15 refs., 4 figs., 11 tabs

  7. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    Science.gov (United States)

    Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

    1998-01-01

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

  8. Criticality experiments with low enriched UO2 fuel rods in water containing dissolved gadolinium

    International Nuclear Information System (INIS)

    Bierman, S.R.; Murphy, E.S.; Clayton, E.D.; Keay, R.T.

    1984-02-01

    The results obtained in a criticality experiments program performed for British Nuclear Fuels, Ltd. (BNFL) under contract with the United States Department of Energy (USDOE) are presented in this report along with a complete description of the experiments. The experiments involved low enriched UO 2 and PuO 2 -UO 2 fuel rods in water containing dissolved gadolinium, and are in direct support of BNFL plans to use soluble compounds of the neutron poison gadolinium as a primary criticality safeguard in the reprocessing of low enriched nuclear fuels. The experiments were designed primarily to provide data for validating a calculation method being developed for BNFL design and safety assessments, and to obtain data for the use of gadolinium as a neutron poison in nuclear chemical plant operations - particularly fuel dissolution. The experiments program covers a wide range of neutron moderation (near optimum to very under-moderated) and a wide range of gadolinium concentration (zero to about 2.5 g Gd/l). The measurements provide critical and subcritical k/sub eff/ data (1 greater than or equal to k/sub eff/ greater than or equal to 0.87) on fuel-water assemblies of UO 2 rods at two enrichments (2.35 wt % and 4.31 wt % 235 U) and on mixed fuel-water assemblies of UO 2 and PuO 2 -UO 2 rods containing 4.31 wt % 235 U and 2 wt % PuO 2 in natural UO 2 respectively. Critical size of the lattices was determined with water containing no gadolinium and with water containing dissolved gadolinium nitrate. Pulsed neutron source measurements were performed to determine subcritical k/sub eff/ values as additional amounts of gadolinium were successively dissolved in the water of each critical assembly. Fission rate measurements in 235 U using solid state track recorders were made in each of the three unpoisoned critical assemblies, and in the near-optimum moderated and the close-packed poisoned assemblies of this fuel

  9. Chelation therapy to treat atherosclerosis, particularly in diabetes: is it time to reconsider?

    Science.gov (United States)

    Lamas, Gervasio A; Ergui, Ian

    2016-08-01

    Case reports and case series have suggested a possible beneficial effect of chelation therapy in patients with atherosclerotic disease. Small randomized trials conducted in patients with angina or peripheral artery disease, however, were not sufficiently powered to provide conclusive evidence on clinical outcomes. The Trial to Assess Chelation Therapy (TACT) was the first randomized trial adequately powered to detect the effects of chelation therapy on clinical endpoints. We discuss results and future research. Expert commentary: Chelation reduced adverse cardiovascular events in a post myocardial infarction (MI) population. Patients with diabetes demonstrated even greater benefit, with a number needed to treat of 6.5 patients to prevent a cardiac event over 5 years, with a 41% relative reduction in risk of a cardiac event (p = 0.0002). These results led to the revision of the ACC/AHA guideline recommendations for chelation therapy, changing its classification from class III to class IIb. TACT2, a replicative trial, will assess the effects of chelation therapy on cardiovascular outcomes in diabetic patients with a prior myocardial infarction. We are seeking participating sites for TACT2.

  10. Present status of PIK gadolinium control

    International Nuclear Information System (INIS)

    Petrov, Yu.V.; Garusov, E.A.; Shustov, V.A.

    1994-01-01

    A liquid control element (LCE) containing a water solution of gadolinium nitrate Gd(NO 3 ) 3 was originally planned for use at the PIK reactor for partial compensation of poisoning and fuel burnup [1-3]. However, a further analysis has shown that quick forcing-out, boiling up or flowing-out of the absorbing solution (though of low probability) can lead to the dangerous prompt overcriticality of the reactor. The results of the analysis are presented as well as the upper limit of the reactivity, quick insertion of which still is safe for the reactor (J.P.N.)

  11. Antibacterial and antibiofilm effects of iron chelators against Prevotella intermedia.

    Science.gov (United States)

    Moon, Ji-Hoi; Kim, Cheul; Lee, Hee-Su; Kim, Sung-Woon; Lee, Jin-Yong

    2013-09-01

    Prevotella intermedia, a major periodontopathogen, has been shown to be resistant to many antibiotics. In the present study, we examined the effect of the FDA-approved iron chelators deferoxamine (DFO) and deferasirox (DFRA) against planktonic and biofilm cells of P. intermedia in order to evaluate the possibility of using these iron chelators as alternative control agents against P. intermedia. DFRA showed strong antimicrobial activity (MIC and MBC values of 0.16 mg ml(-1)) against planktonic P. intermedia. At subMICs, DFRA partially inhibited the bacterial growth and considerably prolonged the bacterial doubling time. DFO was unable to completely inhibit the bacterial growth in the concentration range tested and was not bactericidal. Crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that DFRA significantly decreased the biofilm-forming activity as well as the biofilm formation, while DFO was less effective. DFRA was chosen for further study. In the ATP-bioluminescent assay, which reflects viable cell counts, subMICs of DFRA significantly decreased the bioactivity of biofilms in a concentration-dependent manner. Under the scanning electron microscope, P. intermedia cells in DFRA-treated biofilm were significantly elongated compared to those in untreated biofilm. Further experiments are necessary to show that iron chelators may be used as a therapeutic agent for periodontal disease.

  12. Gadolinium-enhanced MR angiography (Gd-MRA) of thoracic vasculature in an animal model using double-dose gadolinium and quiet breathing

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, R.J.; Strouse, P.J. [Section of Pediatric Radiology, University of Michigan Health System, Ann Arbor (United States); Londy, F.J. [Dept. of Radiology, University of Michigan Hospitals, Ann Arbor, MI (United States); Wakefield, T.W. [Dept. of Surgery, Section of Vascular Surgery, University of Michigan Hospitals, Ann Arbor, MI (United States)

    2001-08-01

    Objective. To evaluate a gadolinium-enhanced MR angiography (Gd-MRA) imaging protocol for the assessment of thoracic vessels using double-dose gadolinium and quiet breathing. An animal model was used to simulate imaging in infants and young children. Material and methods. Six baboons (Papio anubis), mean weight 5.7 kg, were sedated and intubated. After the injection of double-dose Gd-DTPA (0.2 mmol/kg) through a peripheral vein, a coronal spoiled 3D gradient-echo volume acquisition was obtained during quiet breathing. Two radiologists reviewed the images for visualization of aortic arch, brachiocephalic vessel origins, pulmonary arteries (central, upper lobe and descending branches), and pulmonary veins (upper and lower). Results. Visualization was excellent for the aortic arch, brachiocephalic vessel origins, and pulmonary arteries, including the hilar branches. Visualization was excellent for the lower and right upper pulmonary veins and fair for the left upper pulmonary vein. There was excellent agreement between radiologists. Conclusion. Imaging of thoracic vessels with Gd-MRA using double gadolinium during quiet breathing was effective in our animal model. The advantages of this technique include a short imaging time and depiction of vascular segments - branches of pulmonary arteries and intraparenchymal segments of pulmonary veins - not optimally visualized with other non-invasive imaging techniques. (orig.)

  13. Gadolinium-enhanced MR angiography (Gd-MRA) of thoracic vasculature in an animal model using double-dose gadolinium and quiet breathing

    International Nuclear Information System (INIS)

    Hernandez, R.J.; Strouse, P.J.; Londy, F.J.; Wakefield, T.W.

    2001-01-01

    Objective. To evaluate a gadolinium-enhanced MR angiography (Gd-MRA) imaging protocol for the assessment of thoracic vessels using double-dose gadolinium and quiet breathing. An animal model was used to simulate imaging in infants and young children. Material and methods. Six baboons (Papio anubis), mean weight 5.7 kg, were sedated and intubated. After the injection of double-dose Gd-DTPA (0.2 mmol/kg) through a peripheral vein, a coronal spoiled 3D gradient-echo volume acquisition was obtained during quiet breathing. Two radiologists reviewed the images for visualization of aortic arch, brachiocephalic vessel origins, pulmonary arteries (central, upper lobe and descending branches), and pulmonary veins (upper and lower). Results. Visualization was excellent for the aortic arch, brachiocephalic vessel origins, and pulmonary arteries, including the hilar branches. Visualization was excellent for the lower and right upper pulmonary veins and fair for the left upper pulmonary vein. There was excellent agreement between radiologists. Conclusion. Imaging of thoracic vessels with Gd-MRA using double gadolinium during quiet breathing was effective in our animal model. The advantages of this technique include a short imaging time and depiction of vascular segments - branches of pulmonary arteries and intraparenchymal segments of pulmonary veins - not optimally visualized with other non-invasive imaging techniques. (orig.)

  14. Utility of gadolinium as a contrast medium in endovascular therapeutic procedures; Utilidad del gadolinio como medio de contraste en procedimientos terapeuticos endovasculares

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R.; Pardo, M. D.; Gorriz, E.; Gallardo, L. (Hospital de Gran Canaria Dr. Negrin); Carreira, J. M. (Universidad de Santiago de Compostela)

    2001-07-01

    To assess the utility of gadolinium associated with CO{sub 2}, as a contrast medium in angiographic studies related to endovascular therapeutic procedures in patients with suboptimal renal function. Between January 2000 and June 2001, endovascular treatments using CO{sub 2} and gadolinium as contrast medium were performed in 10 patients presenting renal function deterioration (creatinine>1.5 mg/ml). A mean dose of 42 ml of gadolinium was administered. The images acquired in diagnostic and therapeutic studied were satisfactory in every case. There was no evidence of significant increases in the previous urea and creatine levels when measured 24, 48 and 72 hours after the procedure. In combination with CO{sub 2} gadolinium is a useful contrast medium for endovascular therapeutic procedures in patients with suboptimal renal function. (Author) 21 refs.

  15. Engineering an antibody with picomolar affinity to DOTA chelates of multiple radionuclides for pretargeted radioimmunotherapy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orcutt, Kelly Davis; Slusarczyk, Adrian L. [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cieslewicz, Maryelise [Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ruiz-Yi, Benjamin [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bhushan, Kumar R. [Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Frangioni, John V. [Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Wittrup, K. Dane, E-mail: wittrup@mit.ed [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-02-15

    Introduction: In pretargeted radioimmunotherapy (PRIT), a bifunctional antibody is administered and allowed to pre-localize to tumor cells. Subsequently, a chelated radionuclide is administered and captured by cell-bound antibody while unbound hapten clears rapidly from the body. We aim to engineer high-affinity binders to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelates for use in PRIT applications. Methods: We mathematically modeled antibody and hapten pharmacokinetics to analyze hapten tumor retention as a function of hapten binding affinity. Motivated by model predictions, we used directed evolution and yeast surface display to affinity mature the 2D12.5 antibody to DOTA, reformatted as a single chain variable fragment (scFv). Results: Modeling predicts that for high antigen density and saturating bsAb dose, a hapten-binding affinity of 100 pM is needed for near-maximal hapten retention. We affinity matured 2D12.5 with an initial binding constant of about 10 nM to DOTA-yttrium chelates. Affinity maturation resulted in a 1000-fold affinity improvement to biotinylated DOTA-yttrium, yielding an 8.2{+-}1.9 picomolar binder. The high-affinity scFv binds DOTA complexes of lutetium and gadolinium with similar picomolar affinity and indium chelates with low nanomolar affinity. When engineered into a bispecific antibody construct targeting carcinoembryonic antigen, pretargeted high-affinity scFv results in significantly higher tumor retention of a {sup 111}In-DOTA hapten compared to pretargeted wild-type scFv in a xenograft mouse model. Conclusions: We have engineered a versatile, high-affinity, DOTA-chelate-binding scFv. We anticipate it will prove useful in developing pretargeted imaging and therapy protocols to exploit the potential of a variety of radiometals.

  16. MRT of experimental liver abscesses - comparison of a new blood pool contrast agent with gadolinium-DTPA

    International Nuclear Information System (INIS)

    Dick, A.; Adam, G.; Spuentrup, E.; Prescher, A.; Muehler, A.; Guenther, R.W.

    1996-01-01

    Purpose: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. Methods: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 μmol/kg dose of gadolinium polymer and of 100 μmol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. Results: The interindividual comparison (unpaired T-test, p [de

  17. Chelation therapy and cardiovascular disease: connecting scientific silos to benefit cardiac patients.

    Science.gov (United States)

    Peguero, Julio G; Arenas, Ivan; Lamas, Gervasio A

    2014-08-01

    Medical practitioners have treated atherosclerotic disease with chelation therapy for over 50 years. Lack of strong of evidence led conventional practitioners to abandon its use in the 1960s and 1970s. This relegated chelation therapy to complementary and alternative medicine practitioners, who reported good anecdotal results. Concurrently, the epidemiologic evidence linking xenobiotic metals with cardiovascular disease and mortality gradually accumulated, suggesting a plausible role for chelation therapy. On the basis of the continued use of chelation therapy without an evidence base, the National Institutes of Health released a Request for Applications for a definitive trial of chelation therapy. The Trial to Assess Chelation Therapy (TACT) was formulated as a 2 × 2 factorial randomized controlled trial of intravenous EDTA-based chelation vs. placebo and high-dose oral multivitamins and multiminerals vs. oral placebo. The composite primary endpoint was death, reinfarction, stroke, coronary revascularization, or hospitalization for angina. A total of 1708 post-MI patients who were 50 years or older with a creatinine of 2.0 or less were enrolled and received 55,222 infusions of disodium EDTA or placebo with a median follow-up of 55 months. Patients were on evidence-based post-MI medications including statins. EDTA proved to be safe. EDTA chelation therapy reduced cardiovascular events by 18%, with a 5-year number needed to treat (NNT) of 18. Prespecified subgroup analysis revealed a robust benefit in patients with diabetes mellitus with a 41% reduction in the primary endpoint (5-year NNT = 6.5), and a 43% 5-year relative risk reduction in all-cause mortality (5-year NNT = 12). The magnitude of benefit is such that it suggests urgency in replication and implementation, which could, due to the excellent safety record, occur simultaneously. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Biological behaviour of some 67Ga and 64Cu chelates

    International Nuclear Information System (INIS)

    Leonovicova, T.; Angelis, B.; Cifka, J.; Cifkova, I.

    1984-01-01

    Chelates of 67 Ga and 64 Cu with iminodiacetic acid (IDA) and its two phenyl derivatives as well as with nitrilotriacetic acid (NTA) and benzylnitrilotriacetic acid (BNTA) were prepared. All the chelates were found to be negatively charged. A study of the biological distribution of these chelates in rats during time intervals of 3 to 180 min showed that the chelate of 67 Ga with IDA substituted at a phenyl by a hydrophobic substituent is excreted by the kidneys into the urine at a much higher rate than the IDA chelate of 67 Ga. The excretion of NTA and BNTA chelates of 67 Ga is the opposite. Blood clearance of 64 Cu chelates is more rapid than that of 67 Ga chelates. Chelates of 64 Cu accumulate in the liver and with the bile are slowly excreted into the intestines, urinary excretion is negligible. (author)

  19. Liver nodules. MR imaging using extracellular gadolinium agent

    International Nuclear Information System (INIS)

    Yoshimitsu, Kengo; Honda, Hiroshi

    2009-01-01

    Extracellular gadolinium (Gd)-containing contrast medium, including gadopentetate dimeglumine (Gd-DTPA), has been playing a main role in the diagnostic MR imaging of the liver. Its significance is two-fold: assessment of the degree of neovascularity or angiogenesis in its early dynamic phase, and that of bulk of interstitium in its equilibrium phase. With the advent of gadolinium ethoxybenzyl diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA), which can be used as a dynamic study agent by bolus injection in addition to its original use as a tissue-specific agent, some possibility has been suggested that extracellular Gd agent would be no longer available in the near future in the field of liver MR imaging. Neovascularity or arterial supply of a lesion may well be assessed by Gd-EOB-DTPA, when carefully selected pulse sequence and well designed injection protocol are used, as well as by Gd-DTPA. However, the pertinent assessment of interstitium or stroma can never be achieved by Gd-EOB-DTPA or any other contrast medium present. The interstitium of neoplasm, typically called as stromal fibrosis, is generated through the interaction between the neoplasm per se and its host, and its clinicopathological significance related to disease prognosis has well been established in some disease entities. Extracellular Gd agent is the only contrast medium that can provide information regarding the tumor stroma in a simple, easy, safe and non-invasive fashion, when properly used. This review article discusses, dynamic MR imaging features of representative liver diseases, including several recent topics. From technical point of view, 3D gradient-echo sequence with fat suppression should be used for dynamic studies along with tailored injection protocol using autoinjector and saline flush. Vascularity of hepatocellular carcinoma (HCC) can now be properly assessed by dynamic MR with approximately 90% concordance with CT during hepatic arteriography. Portal phase images can be used to

  20. Decomposition rates of radiopharmaceutical indium chelates in serum

    International Nuclear Information System (INIS)

    Yeh, S.M.; Meares, C.F.; Goodwin, D.A.

    1979-01-01

    The rates at which six small aminopolycarboxylate chelates of trivalent 111 In and three protein-bound chelates of 111 In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37 deg C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day - one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures. (author)

  1. Review of actinide decorporation with chelating agents

    Energy Technology Data Exchange (ETDEWEB)

    Ansoborlo, E. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/CETAMA), 30 - Marcoule (France); Amekraz, B.; Moulin, Ch. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Moulin, V. [CEA Saclay, Dir. du Developpement et de l' Innovation Nucleares (DEN/DDIN/MR), 91 - Gif Sur Yvette (France); Taran, F. [CEA Saclay (DSV/DBJC/SMMCB), 91 - Gif-sur-Yvette (France); Bailly, Th.; Burgada, R. [Centre National de la Recherche Scientifique (CNRS/LCSB/UMR 7033), 93 - Bobigny (France); Henge-Napoli, M.H. [CEA Valrho, Site de Marcoule (INSTN), 30 (France); Jeanson, A.; Den Auwer, Ch.; Bonin, L.; Moisy, Ph. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS), 30 - Marcoule (France)

    2007-10-15

    In case of accidental release of radionuclides in a nuclear facility or in the environment, internal contamination (inhalation, ingestion or wound) with actinides represents a severe health risk to human beings. It is therefore important to provide effective chelation therapy or decorporation to reduce acute radiation damage, chemical toxicity, and late radiation effects. Speciation governs bioavailability and toxicity of elements and it is a prerequisite tool for the design and success of new ligands or chelating agents. The purpose of this review is to present the state-of-the-art of actinide decorporation within biological media, to recall briefly actinide metabolism, to list the basic constraints of actinide-ligand for development, to describe main tools developed and used for decorporation studies, to review mainly the chelating agents tested for actinides, and finally to conclude on the future trends in this field. (authors)

  2. Gadolinium released by the linear gadolinium-based contrast-agent Gd-DTPA decreases the activity of human epithelial Na+ channels (ENaCs).

    Science.gov (United States)

    Knoepp, Fenja; Bettmer, Joerg; Fronius, Martin

    2017-05-01

    Gadolinium-based-contrast-agents (GBCAs) are used for magnetic-resonance-imaging and associated with renal and cardiovascular adverse reactions caused by released Gd 3+ ions. Gd 3+ is also a modulator of mechano-gated ion channels, including the epithelial Na + channel (ENaC) that is expressed in kidney epithelium and the vasculature. ENaC is important for salt-/water homeostasis and blood pressure regulation and a likely target of released Gd 3+ from GBCAs causing the above-mentioned adverse reactions. Therefore this study examined the effect of Gd 3+ and GBCAs on ENaC's activity. Human αβγENaC was expressed in Xenopus laevis oocytes and exposed to Gd 3+ , linear (Gd-DTPA, Magnevist) or cyclic (Dotarem) GBCAs. Transmembrane ion-currents (I M ) were recorded by the two-electrode-voltage-clamp technique and Gd 3+ -release by Gd-DTPA was confirmed by inductively coupled plasma-mass spectrometry. Gd 3+ exerts biphasic effects on ENaC's activity: ≤0.3mmol/l decreased I M which was preventable by DEPC (modifies histidines). Strikingly Gd 3+ ≥0.4mmol/l increased I M and this effect was prevented by cysteine-modifying MTSEA. Linear Gd-DTPA and Magnevist mimicked the effect of ≤0.3mmol/l Gd 3+ , whereas the chelator DTPA showed no effect. Gd 3+ and Gd-DTPA increased the IC 50 for amiloride, but did not affect ENaC's self-inhibition. Interestingly, cyclic Gd-DOTA (Dotarem) increased I M to a similar extent as its chelator DOTA, suggesting that the chelator rather than released Gd 3+ is responsible for this effect. These results confirm Gd 3+ -release from linear Gd-DTPA and indicate that the released Gd 3+ amount is sufficient to interfere with ENaC's activity to provide putative explanations for GBCA-related adverse effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Gadolinium-enhanced magnetic resonance imaging in acute myocardial infarction

    International Nuclear Information System (INIS)

    Dijkman, P.R.M. van; Wall, E.E. van der; Roos, A. de; Doornbos, J.; Laarse, A. van der; Voorthuisen, A.E. van; Bruschke, A.V.G.; Rossum, A.C. van

    1990-01-01

    To evaluate he usefulness of the paramagnetic contrast agent Gadolinium-DTPA (diethylenetriaminepentaacetic acid) in Magnetic Resonance. Imaging of acute myocardial infarction, we studied a total of 45 patients with a first acute myocardial infarction by ECG-gated magnetic resonance imaging before and after intravenous administration of 0.1 mmol/kg Gadolinium-DTPA. All patients received thrombolytic treatment by intravenous streptokinase. The magnetic resonance imaging studies were preformed after a meam of 88 h (range 15-241) after the acute onset of acute myocardial infarction. Five patients without evidence of cardiac disease served as controls. Spin-echo measurements (TE 30 ms) were made using a Philips Gyroscan (0.5 Tesla) or a Teslacon II (0.6 Tesla). The 45 patients were divided into four groups of patients. In Group I( patients) Gadolinium-DTPA improved the detection of myocardial infarction by Gadolinium-DTPA. In Group II (20 patients) the magnetic resonance imaging procedure was repeated every 10 min for up to 40 min following administration of Gadolinium-DTPA. Optimal contrast enhancement was obtained 20-25 min after Gadolinium-DTPA. In Group III (27 patients) signal intensities were significantly higher in the patients who underwent the magnetic resonance imaging study more than 72 h (mean 120) after the acute event, suggesting increased acculumation of Gadolinium-DTPA in a more advanced stage of the infarction process. In Group IV (45 patients) Gadolinium-DTPA was administered in an attempt to distinguish between reperfused and nonreperfused myocardial areas after thrombolytic treatment for acute myocardial infarction. The signal intensities did not differ, but reperfused areas showed a more homogeneous aspect whereas nonreperfused areas were visualized as a more heterogeneous contrast enhancement. It is concluded that magnetic resonance imaging using the contrast agent Gadolinium-DTPA significantly improves the detection of infarcted myocardial areas

  4. Chelated mineral supplements for Nelore: quality and early embryonic development

    Directory of Open Access Journals (Sweden)

    Camila Pasa

    2014-01-01

    embryos, cells in the morula stage, embryos in blastocyst stage embryos and expanded blastocyst stage assessed on day six of culture. Moreover, there was no effect of supplementation in the collection for a number of in vitro matured oocytes (IVM (p = 0.0981, 24.9166 ± 4.2878 GC and GS 16.2500 ± 2.6057 , number of cleaved oocytes (p = 0.0902 for the GC animals and animals 13.9166 ± 2.4103; 9.0833 ± 1.2759 GS and number of embryos to the blastocyst stage assessed in the initial 06 days (p = 0.0091, 2.7500 ± 0.4909 GC and GS 5.2857 ± 0.9184. Oral supplementation with minerals zinc, copper and selenium chelate via protein supplements at the levels and conditions for nutrient management in this experiment did not influence the parameters of percentage of cleaved oocytes, total number of embryos, percentage of embryos, cells in the morula stage, embryos in the blastocyst stage and expanded blastocyst evaluated on day 06 of cultivation, however had a significant effect for in vitro matured oocytes, cleavage and blastocyst stage embryos in the initial young Nelore cows.

  5. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  6. Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better.

    Science.gov (United States)

    Avedano, Stefano; Botta, Mauro; Haigh, Julian S; Longo, Dario L; Woods, Mark

    2013-08-05

    The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd(3+) chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of monohydrated Gd(3+) chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd(3+)-water proton distance (rGdH), and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd(3+) chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd(3+) chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with "optimal" dissociative water exchange kinetics is actually lower than that of an isomeric chelate with "suboptimal" dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging ("optimal") chelate exhibiting lower relaxivity than the "suboptimally" exchanging isomer. The difference between the chelates arises from a non-field-dependent parameter: either the hydration number (q) or rGdH. For solution state Gd(3+) chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate--i.e., the number and position of closely associating water molecules. The hydration state (q/rGdH(6)) of a chelate is intrinsically linked to its dissociative water exchange rate kex, and the interrelation of these parameters must be considered when examining the relaxivity of Gd(3+) chelates. The data presented herein indicate that the changes in the hydration parameter (q/rGdH(6)) associated with changing dissociative

  7. Effect of organic bases on extraction of gadolinium carboxylates

    International Nuclear Information System (INIS)

    Sukhan, V.V.; Frankovskij, V.A.

    1982-01-01

    The effect of pyridine, 2-aminopyridine, benzylamine, antipyrine and o-phenanthroline on the extraction of capronates and bromocapronates of gadolinium with chloroform is studied. Out of the studied organic bases benzylamine produces the highest synergetic effect. In the absence of organic bases gadolinium carboxylates, solvated by three molecules of carbonic acids, are extracted into organic phase. A possihility of extractional separation of gadolinium from comparable amounts of iron with the mixture of 1 M solutions of caproic or bromocaproic acids with 1 M benzylamine from 0.1 M solution of tartaric acids is shown [ru

  8. Alkali metal and alkali earth metal gadolinium halide scintillators

    Science.gov (United States)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  9. Magnetic refrigeration cycle analysis using selected thermodynamic property characterizations for gadolinium gallium garnet

    International Nuclear Information System (INIS)

    Murphy, R.W.

    1992-01-01

    Magneto-thermodynamic property characterizations were selected, adapted, and compared to material property data for gadolinium gallium garnet in the temperature range 4--40 K and magnetic field range 0--6 T. The most appropriate formulations were incorporated into a model in which methods similar to those previously developed for other materials and temperature ranges were used to make limitation and relative performance assessments of Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. Analysis showed that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as those for materials previously examined, substantial improvements in cooling capacity/temperature lift combinations can be achieved using regenerative cycles within specified fields limits if significant loss mechanisms are mitigated

  10. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  11. Clinical experience of gadolinium-DTPA

    International Nuclear Information System (INIS)

    Takemoto, Kazumasa; Inoue, Yuichi; Hashimoto, Hiromi

    1986-01-01

    Magnetic resonance imaging was performed before and after intravenous administration of gadolinium-DTPA (Gd-DTPA) in 9 patients with intracranial tumors (8) and a spinal tumor (1). In this study IR (2100/600) and short SE (600/40) were used. After administration of Gd-DTPA, signal intensity of tumors increased in all cases. Contrast enhanced MRI with Gd-DTPA was useful in metastatic brain tumor, cerebeller astrocytoma and glioblastoma to differentiate the tumor from edema. Since meningiomas were clearly demonstrated and differentiated from edema. Gd-DTPA seems to be not required for the diagnosis of meningiomas. No severe side effect were encountered after injection of Gd-DTPA. (author)

  12. Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol.

    Science.gov (United States)

    Jingu, Akiko; Fukuda, Junya; Taketomi-Takahashi, Ayako; Tsushima, Yoshito

    2014-10-06

    Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR).The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. The protocol was applied to a total of 252 examinations (153 patients, ages 15-87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma.

  13. Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol

    International Nuclear Information System (INIS)

    Jingu, Akiko; Fukuda, Junya; Taketomi-Takahashi, Ayako; Tsushima, Yoshito

    2014-01-01

    Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR). The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. The protocol was applied to a total of 252 examinations (153 patients, ages 15–87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma

  14. Pineapple juice labeled with gadolinium: a convenient oral contrast for magnetic resonance cholangiopancreatography

    International Nuclear Information System (INIS)

    Coppens, Emmanuel; Metens, Thierry; Winant, Catherine; Matos, Celso

    2005-01-01

    The aim of our study was to prepare in vitro a pineapple juice (PJ) solution labeled with a minimal gadolinium concentration working as a negative contrast agent in heavily T2-weighted imaging and to assess that solution in vivo as a negative oral contrast agent for magnetic resonance cholangiopancreatography (MRCP). Three PJs were compared in vitro according to their T2. Increasing concentrations of gadolinium (Gd)-DOTA in PJ were assessed in vitro for T2 reduction. Single-shot turbo spin echo T2-weighted MR cholangiopancreatograms were obtained for 35 patients with suspected biliopancreatic duct disease, before and after ingestion of the PJ/Gd-DOTA solution. Signal intensity (SI) measurements of gastroduodenal lumens, pancreatobiliary ducts, and image quality scores were obtained systematically before and after contrast ingestion. The in vitro selected Gd-DOTA concentration in the PJ was 2.76 mmol/l. Ingestion of 180 ml of PJ labeled with 1 ml of Gd-DOTA eliminated efficiently the gastroduodenal SI in MRCP, improving significantly the rates of complete visualization of the pancreatobiliary ducts (P<0.01) and the MRCP image quality scores (P<0.05). All patients easily ingested the contrast solution and found the solution palatable. PJ labeled with gadolinium constituted an efficient and convenient negative oral contrast agent for MRCP. (orig.)

  15. Pineapple juice labeled with gadolinium: a convenient oral contrast for magnetic resonance cholangiopancreatography

    Energy Technology Data Exchange (ETDEWEB)

    Coppens, Emmanuel; Metens, Thierry; Winant, Catherine; Matos, Celso [Hopital Erasme, Universite Libre de Bruxelles, Department of Radiology, Division of Magnetic Resonance, Brussels (Belgium)

    2005-10-01

    The aim of our study was to prepare in vitro a pineapple juice (PJ) solution labeled with a minimal gadolinium concentration working as a negative contrast agent in heavily T2-weighted imaging and to assess that solution in vivo as a negative oral contrast agent for magnetic resonance cholangiopancreatography (MRCP). Three PJs were compared in vitro according to their T2. Increasing concentrations of gadolinium (Gd)-DOTA in PJ were assessed in vitro for T2 reduction. Single-shot turbo spin echo T2-weighted MR cholangiopancreatograms were obtained for 35 patients with suspected biliopancreatic duct disease, before and after ingestion of the PJ/Gd-DOTA solution. Signal intensity (SI) measurements of gastroduodenal lumens, pancreatobiliary ducts, and image quality scores were obtained systematically before and after contrast ingestion. The in vitro selected Gd-DOTA concentration in the PJ was 2.76 mmol/l. Ingestion of 180 ml of PJ labeled with 1 ml of Gd-DOTA eliminated efficiently the gastroduodenal SI in MRCP, improving significantly the rates of complete visualization of the pancreatobiliary ducts (P<0.01) and the MRCP image quality scores (P<0.05). All patients easily ingested the contrast solution and found the solution palatable. PJ labeled with gadolinium constituted an efficient and convenient negative oral contrast agent for MRCP. (orig.)

  16. Morphological imaging and T2 and T2* mapping of hip cartilage at 7 Tesla MRI under the influence of intravenous gadolinium

    International Nuclear Information System (INIS)

    Lazik-Palm, Andrea; Geis, Christina; Goebel, Juliane; Theysohn, Jens M.; Kraff, Oliver; Johst, Soeren; Ladd, Mark E.; Quick, Harald H.

    2016-01-01

    To investigate the influence of intravenous gadolinium on cartilage T2 and T2* relaxation times and on morphological image quality at 7-T hip MRI. Hips of 11 healthy volunteers were examined at 7 T. Multi-echo sequences for T2 and T2* mapping, 3D T1 volumetric interpolated breath-hold examination (VIBE) and double-echo steady-state (DESS) sequences were acquired before and after intravenous application of gadolinium according to a delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) protocol. Cartilage relaxation times were measured in both scans. Morphological sequences were assessed quantitatively using contrast ratios and qualitatively using a 4-point Likert scale. Student's t-test, Pearson's correlation (ρ) and Wilcoxon sign-rank test were used for statistical comparisons. Pre- and post-contrast T2 and T2* values were highly correlated (T2: acetabular: ρ = 0.76, femoral: ρ = 0.77; T2*: acetabular: ρ = 0.80, femoral: ρ = 0.72). Gadolinium enhanced contrasts between cartilage and joint fluid in DESS and T1 VIBE according to the qualitative (p = 0.01) and quantitative (p < 0.001) analysis. The delineation of acetabular and femoral cartilage and the labrum predominantly improved with gadolinium. Gadolinium showed no relevant influence on T2 or T2* relaxation times and improved morphological image quality at 7 T. Therefore, morphological and quantitative sequences including dGEMRIC can be conducted in a one-stop-shop examination. (orig.)

  17. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-08-21

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  18. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    International Nuclear Information System (INIS)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-01-01

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  19. Bone marrow and chelatable iron in patients with protein energy ...

    African Journals Online (AJOL)

    chelatable iron is present and is excreted in the urine of children with kwashiorkor ... venous blood sample was drawn for routine biochemical and haematological .... storage.l.1:m In response to chelation, the kwashiorkor children excrete large ...

  20. Gadolinium recovery from aqueous pharmaceutical residuals by pulsed electrical discharge; Rueckgewinnung von Gadolinium aus pharmazeutischen Abwaessern mittels gepulster elektrischer Entladung

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Tom; Froehlich, Peter [TU Bergakademie Freiberg (Germany); Seifert, Martin; Jacob-Seifert, Karin [FNE Entsorgungsdienste GmbH, Freiberg (Germany)

    2017-02-15

    Advanced oxidation process (AOP) is an oxidation step releasing reactive oxygen species by pulsed electrical discharge in aqueous systems. In contrast to processes generating ozone by external UV radiation this method is feasible for turbid liquids with solid particles. This method is currently used in particular in the field of purification of chemically polluted waste waters. In the present application AOP is applied for partial degradation of the organic ligand system of a gadolinium X-ray contrast agent to separate gadolinium subsequently by adding caustic soda to precipitate > 99% of gadolinium.

  1. Radiopharmaceutical chelates and method of external imaging

    International Nuclear Information System (INIS)

    Loberg, M.D.; Callery, P.S.; Cooper, M.

    1977-01-01

    A chelate of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The invention also includes preparative methods therefor

  2. Use of chelating agents as immovable phase in extraction chromatography

    International Nuclear Information System (INIS)

    Sebesta, F.

    1978-01-01

    Extraction chromatography using chelating agents is reviewed. The theory of element extraction by chelating agents and factors influencing this process (pH, extracting agent concentration in organic phase, masking agent concentration in aqueous phase) are briefly considered. The effect of kinetic factors on the extraction chromatography process is discussed. Ways of preparing columns are emphasized. Examples of using chelating reagents in various extraction chromatography systems are given. β-Diketones, oximes, hydroxamic acids, dithizon, diethyl dithiocarbamic acid are chosen as chelating agents

  3. Production of gadolinium nitrate for TAPS 3 and 4 PHWR

    International Nuclear Information System (INIS)

    Mishra, S.L.; Ramakrishnan, P.; Iyer, N.S.; Singh, Harvinderpal

    2004-01-01

    In India, gadolinium nitrate is being used for the first time in PHWR at Tarapur. Gadolinium is preferred over boron due to high neutron cross section and the water soluble nitrate form works efficiently for reactivity control through moderator liquid poison addition system (MLPS) as well as for reactor shut down system (SDS2). Low concentration of gadolinium (0.1-0.2 g/l) in heavy water is sufficient to shut down the reactor in a very short time. After use, the small amount of gadolinium can be separated quickly from heavy water by ion exchange process. In this paper separation of Gd using of 2-ethyl hexyl phosphoric acid mono 2-ethyl hexyl ester EHEHPA as an extractant has been described

  4. Deposit of isotopically modified gadolinium suitable to detect solar neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Cribier, M

    1999-04-01

    Consideration on the possibility to find gadolinium with a modified isotopic composition are envisaged, in particular with respect to the important use of this element by the nuclear energy. These possibility could exist in the far future. (author)

  5. Human Aortic Endothelial Cell Labeling with Positive Contrast Gadolinium Oxide Nanoparticles for Cellular Magnetic Resonance Imaging at 7 Tesla

    Directory of Open Access Journals (Sweden)

    Yasir Loai

    2012-03-01

    Full Text Available Positive T1 contrast using gadolinium (Gd contrast agents can potentially improve detection of labeled cells on magnetic resonance imaging (MRI. Recently, gadolinium oxide (Gd2O3 nanoparticles have shown promise as a sensitive T1 agent for cell labeling at clinical field strengths compared to conventional Gd chelates. The objective of this study was to investigate Gado CELLTrack, a commercially available Gd2O3 nanoparticle, for cell labeling and MRI at 7 T. Relaxivity measurements yielded r1 = 4.7 s−1 mM−1 and r2/r1 = 6.2. Human aortic endothelial cells were labeled with Gd2O3 at various concentrations and underwent MRI from 1 to 7 days postlabeling. The magnetic resonance relaxation times T1 and T2 of labeled cell pellets were measured. Cellular contrast agent uptake was quantified by inductively coupled plasma–atomic emission spectroscopy, which showed very high uptake compared to conventional Gd compounds. MRI demonstrated significant positive T1 contrast and stable labeling on cells. Enhancement was optimal at low Gd concentrations, attained in the 0.02 to 0.1 mM incubation concentration range (corresponding cell uptake was 7.26 to 34.1 pg Gd/cell. Cell viability and proliferation were unaffected at the concentrations tested and up to at least 3 days postlabeling. Gd2O3 is a promising sensitive and stable positive contrast agent for cellular MRI at 7 T.

  6. Enhancement effects and relaxivities of gadolinium-DTPA at 1.5 versus 3 tesla. A phantom study

    International Nuclear Information System (INIS)

    Sasaki, Makoto; Shibata, Eri; Kanbara, Yoshiyuki; Ehara, Shigeru

    2005-01-01

    The purpose of this study was to investigate the difference in enhancement effects and relaxivities of the gadolinium chelate at 1.5 and 3 Tesla (T) and to elucidate the contribution of the high magnetic field to contrast enhancement in spin-echo (SE) and gradient-echo (GRE) images. Phantoms containing water with or without gadopentetate dimeglumine (Gd-DTPA) at different concentrations were scanned using 1.5T and 3T MRI scanners of the same manufacturer and under the same temperature conditions and scanning parameters. Relaxivities of gadolinium, R 1 and R 2 , were estimated from serial T 1 and T 2 values of the phantoms using linear regression. Contrast enhancement ratios in SE and GRE T 1 -weighted images were compared at 1.5 and 3T. The R 1 and R 2 of Gd-DTPA at 1.5 and 3T were 4.79 and 5.14, and 4.50 and 5.09, respectively. Although the relaxivities at 3T were slightly lower than those at 1.5T, the contrast enhancement ratio improved in both SE and GRE images as a result of T 1 prolongation of the water at 3T. The decrease in relaxivities of the Gd-DTPA at 3T appears to be so small that T 1 prolongation of the water improves contrast enhancement, suggesting a potential clinical advantage in administration of Gd-DTPA at high field strength. (author)

  7. Modeling for Colloid and Chelator Facilitated Nuclide Transport in Radioactive Waste Disposal System

    International Nuclear Information System (INIS)

    Lee, Youn Myoung; Jeong, Jong Tae

    2010-08-01

    A modeling study and development of a total system performance assessment (TSPA) program template, by which assessment of safety and performance for a radioactive waste repository with normal and/or abnormal nuclide release cases can be made has been developed. Colloid and chelator facilitated transport that is believed to result for faster nuclide transport in various mediabothinthegeosphereandbiospherehas been evaluated deterministically and probabilistically to demonstrate the capability of the template developed through this study. To this end colloid and chelator facilitated nuclide transport has been modeled rather strainghtforwardly with assumed data through this study by utilizing some powerful function offered by GoldSim. An evaluation in view of apparent influence of colloid and chelator on the nuclide transport in the various media in and around a repository system with data assumed are illustrated

  8. Chelating agents as stationary phase in extraction chromatography, ch. 11

    International Nuclear Information System (INIS)

    Sebesta, F.

    1975-01-01

    Chelating agents have been used largely in extraction chromatography for separations related to activation analysis, for concentration of metals from dilute solutions, and for preparation of radiochemically pure or carrier-free radionuclides. This review deals with the theory of extraction by chelating agents, the experimental technique, and the chelating agents and systems used (β-diketones, oximes, hydroxamic acid, dithizone and diethyldithiocarbamic acid)

  9. A model to calculate the burn of gadolinium in PWR

    International Nuclear Information System (INIS)

    Sannazzaro, L.R.

    1983-01-01

    A cell model to calculate the burnup of a PWR fuel element with gadolinium as a poison, projected by KWU, is presented. With the model proposed, the burn of the gadolinium isotopes is analyzed, as well as the effect of these isotopes in the fuel element behaviour. The results obtained with this cell model are compared with those obtained by a conventional cell model. (E.G.) [pt

  10. Use of gadolinium-DTPA in inflammatory skeletal diseases

    International Nuclear Information System (INIS)

    Mueller-Miny, H.; Reiser, M.; Erlemann, R.; Peters, P.E.

    1989-01-01

    In bacterial osteomyelitis and arthritis paraossal spreading is sensitively detected by gadolinium-DTPA. Abscessous cavities and membranes are better imaged than with T1- and T2-weighted MRT sequences without contrast medium. In chronic osteomylitis it is of advantage, that also florid inflammatory processes can be detected. Gadolinium-DTPA selectively induces a signal increase in the synovitic pannus, that allows the differentiation from articular effusion. In inflammed particular soft tissue only a retarded signal increase is detectable. (author)

  11. Evaluation of Novel 64Cu-Labeled Theranostic Gadolinium-Based Nanoprobes in HepG2 Tumor-Bearing Nude Mice

    Science.gov (United States)

    Hu, Pengcheng; Cheng, Dengfeng; Huang, Tao; Banizs, Anna B.; Xiao, Jie; Liu, Guobing; Chen, Quan; Wang, Yuenan; He, Jiang; Shi, Hongcheng

    2017-09-01

    Radiation therapy of liver cancer is limited by low tolerance of the liver to radiation. Radiosensitizers can effectively reduce the required radiation dose. AGuIX nanoparticles are small, multifunctional gadolinium-based nanoparticles that can carry radioisotopes or fluorescent markers for single-photon emission computed tomography (SPECT), positron emission tomography (PET), fluorescence imaging, and even multimodality imaging. In addition, due to the high atomic number of gadolinium, it can also serve as a tumor radiation sensitizer. It is critical to define the biodistribution and pharmacokinetics of these gadolinium-based nanoparticles to quantitate the magnitude and duration of their retention within the tumor microenvironment during radiotherapy. Therefore, in this study, we successfully labeled AGuIX with 64Cu through the convenient built-in chelator. The biodistribution studies indicated that the radiotracer 64Cu-AGuIX accumulates to high levels in the HepG2 xenograft of nude mice, suggesting that it would be a potential theranostic nanoprobe for image-guided radiotherapy in HCC. We also used a transmission electron microscope to confirm AGuIX uptake in the HepG2 cells. In radiation therapy studies, a decrease in 18F-FDG uptake was observed in the xenografts of the nude mice irradiated with AGuIX, which was injected 1 h before. These results provide proof-of-concept that AGuIX can be used as a theranostic radiosensitizer for PET imaging to guide radiotherapy for liver cancer.

  12. Gadolinium-conjugated PLA-PEG nanoparticles as liver targeted molecular MRI contrast agent.

    Science.gov (United States)

    Chen, Zhijin; Yu, Dexin; Liu, Chunxi; Yang, Xiaoyan; Zhang, Na; Ma, Chunhong; Song, Jibin; Lu, Zaijun

    2011-09-01

    A nanoparticle magnetic resonance imaging (MRI) contrast agent targeted to liver was developed by conjugation of gadolinium (Gd) chelate groups onto the biocompatible poly(l-lactide)-block-poly (ethylene glycol) (PLA-PEG) nanoparticles. PLA-PEG conjugated with diethylenetriaminopentaacetic acid (DTPA) was used to formulate PLA-PEG-DTPA nanoparticles by solvent diffusion method, and then Gd was loaded onto the nanoparticles by chelated with the unfolding DTPA on the surface of the PLA-PEG-DTPA nanoparticles. The mean size of the nanoparticles was 265.9 ± 6.7 nm. The relaxivity of the Gd-labeled nanoparticles was measured, and the distribution in vivo was evaluated in rats. Compared with conventional contrast agent (Magnevist), the Gd-labeled PLA-PEG nanoparticles showed significant enhancement both on liver targeting ability and imaging signal intensity. The T(1) and T(2) relaxivities per [Gd] of the Gd-labeled nanoparticles was 18.865 mM(-1) s(-1) and 24.863 mM(-1) s(-1) at 3 T, respectively. In addition, the signal intensity in vivo was stronger comparing with the Gd-DTPA and the T(1) weight time was lasting for 4.5 h. The liver targeting efficiency of the Gd-labeled PLA-PEG nanoparticles in rats was 14.57 comparing with Magnevist injection. Therefore, the Gd-labeled nanoparticles showed the potential as targeting molecular MRI contrast agent for further clinical utilization.

  13. Fundamental study of DSA images using gadolinium contrast agent

    International Nuclear Information System (INIS)

    Nagashima, Hiroyuki; Shiraishi, Akihisa; Igarashi, Hitoshi; Sakamoto, Hajime; Sano, Yoshitomo

    2002-01-01

    Most contrast agents used in digital subtraction angiography (DSA) are non-ionic iodinated contrast agents, which can cause severe side effects in patients with contraindications for iodine or allergic reactions to iodine. Therefore, DSA examinations using carbon dioxide gas or examinations done by magnetic resonance imaging (MRI) and ultrasound (US) were carried out in these patients. However, none of these examinations provided mages as clear as those of DSA with an iodinated contrast agent. We experienced DSA examination using a gadolinium contrast agent in a patient contraindicated for iodine. The patient had undergone MRI examination with a gadolinium contrast agent previously without side effects. The characteristics of gadolinium and the iodinated contrast agent were compared, and the DSA images obtained clinically using these media were also evaluated. The signal-to-noise (SN) ratio of the gadolinium contrast agent was the highest at tube voltages of 70 to 80 kilovolts and improved slightly when the image intensifier (I.I.) entrance dose was greater than 300 μR (77.4 nC/kg). The dilution ratios of five iodinated contrast agents showed the same S/N value as the undiluted gadolinium contrast agent. Clinically, the images obtained showed a slight decrease in contrast but provided the data necessary to make a diagnosis and made it possible to obtain interventional radiology (IVR) without any side effects. DSA examinations using a gadolinium contrast agent have some benefit with low risk and are thought to be useful for patients contraindicated for iodine. (author)

  14. Bone marrow blood supply in gadolinium-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Saifuddin, A.; Bann, K.; Ridgway, J.P.; Butt, W.P.

    1994-01-01

    A retrospective study was performed to determine whether bone blood supply can be assessed on gadolinium-enhanced magnetic resonance imaging. Lumbar spine magnetic resonance imaging (MRI) examinations of 49 patients attending for post-laminectomy examination were reviewed (30 male, 19 female, mean age 46.4 years, age range 23-84 years). Each study included sagittal T1-weighted spin echo sequences before and after gadolinium administration. Regions of interest were drawn within the L3 vertebral body from a parasagittal slice from each sequence. Signal intensity (SI) values were ascertained and the percentage increase in SI was calculated. For each patient, changes in receiver gain for pre- and post-gadolinium images were corrected by an image scaling factor. In all cases, a measurable increase in SI was found (mean 15.3%, range 4.4-55.7) due to bone vascularity. The results give no indication of the quantity or timing of blood supply but provide a basis for further work. (orig.)

  15. Gadolinium prevents high airway pressure-induced permeability increases in isolated rat lungs.

    Science.gov (United States)

    Parker, J C; Ivey, C L; Tucker, J A

    1998-04-01

    To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 microM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient (Kfc), a measure of capillary hydraulic conductivity. Kfc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, Kfc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, Kfc was unchanged from baseline (0.060 +/- 0.010 ml . min-1 . cmH2O-1 . 100 g-1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last Kfc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

  16. Effects of lead and chelators on growth, photosynthetic activity and Pb uptake in Sesbania drummondii grown in soil

    International Nuclear Information System (INIS)

    Ruley, Adam T.; Sharma, Nilesh C.; Sahi, Shivendra V.; Singh, Shree R.; Sajwan, Kenneth S.

    2006-01-01

    Effects of lead (Pb) and chelators, such as EDTA, HEDTA, DTPA, NTA and citric acid, were studied to evaluate the growth potential of Sesbania drummondii in soils contaminated with high concentrations of Pb. S. drummondii seedlings were grown in soil containing 7.5 g Pb(NO 3 ) 2 and 0-10 mmol chelators/kg soil for a period of 2 and 4 weeks and assessed for growth profile (length of root and shoot), chlorophyll a fluorescence kinetics (F v /F m and F v /F o ) and Pb accumulations in root and shoot. Growth of plants in the presence of Pb + chelators was significantly higher (P v /F m and F v /F o values of treated seedlings remained unaffected, indicating normal photosynthetic efficiency and strength of plants in the presence of chelators. On application of chelators, while root uptake of Pb increased four-five folds, shoot accumulations increased up to 40-folds as compared to controls (Pb only) depending on the type of chelator used. Shoot accumulations of Pb varied from 0.1 to 0.42% (dry weight) depending on the concentration of chelators used. - Sesbania drummondii tolerates and accumulates high concentrations of Pb

  17. Theoretical analysis of the influence of chelate-ring size and vicinal effects on electronic circular dichroism spectra of cobalt(III) EDDA-type complexes.

    Science.gov (United States)

    Wang, Ai; Wang, Yuekui; Jia, Jie; Feng, Lixia; Zhang, Chunxia; Liu, Linlin

    2013-06-20

    To assess the contributions of configurational and vicinal effects as well as chelate-ring size to rotational strengths, the geometries of a series of cobalt(III) complexes [Co(EDDA-type)(L)](±) with the tetradentate EDDA-type ligands, EDDA (ethylenediamine-N,N'-diacetate), DMEDDA (N,N'-dimethylethylenediamine-N,N'-diacetate), DEEDDA (N,N'-diethylethylenediamine-N,N'-diacetate), and a bidentate ancillary ligand L (L = ethylenediamine, oxalate, carbonate, (S)-alanine, and malonate) in aqueous solution have been optimized at the DFT/B3LYP/6-311++G(2d,p) level of theory. Based on the optimized geometries, the excitation energies and oscillator and rotational strengths have been calculated using the time-dependent density functional theory (TDDFT) method with the same functional and basis set. The calculated circular dichroism (CD) curves are in excellent agreement with the observed ones except for some small red or blue shifts in peak wavelengths. For the influence of chelate-ring size of the bidentate ligands on the CD intensities, a qualitative analysis together with the quantitative TDDFT calculation reveal that it depends on the symmetry of the cobalt-EDDA backbone. For the s-cis-isomers, the influence is negligible due to the perturbation is symmetric. For the uns-cis-isomers, the perturbation is unsymmetric. Since a small ring size means a large perturbation, this leads to the integral CD intensities decreasing with increasing the chelate ring size. The vicinal effects of asymmetric nitrogens incorporate both the substitutent effects and conformational relaxation effects, with the former being dominant. By analyzing the contributions of chiral arrays to rotational strengths, we found that the part of contributions dominated by the S-type chiral nitrogens could be considered as a good measure for the vicinal effects of chiral nitrogens. In addition, we found that the twist form (δ/λ) of the backbone ethylenediamine ring (E-ring) of the coordinated EDDA

  18. [Susceptibility of enterococci to natural and synthetic iron chelators].

    Science.gov (United States)

    Lisiecki, Paweł; Mikucki, Jerzy

    2002-01-01

    A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

  19. Isotope shift studies in gadolinium spectra

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Saksena, G.D.; Venugopalan, A.

    1975-01-01

    Isotope shift studies have been carried out in the gadolinium spectrum using a recording Fabry-Perot spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. The source used is a liquid-nitrogen-cooled hollow cathode with Ne as the carrier gas and operating at about 30 mA. Isotope shifts Δsigma (156-160) have been recorded in 350 transitions of Gd I and Gd II. In the case of the Gd I spectrum, the transitions studied presently involve almost all the reported configurations assigned to the energy levels of Gd I. The odd configurations are 4f 7 5d6s 2 , 4f 7 5d 2 6s, 4f 7 5d 3 , 4f 8 6s6p, 4f 7 5d6s7s and 4f 7 6s 2 6p, and the even ones are 4f 8 6s 2 , 4f 7 5d6s6p, 4f 7 6s 2 6p, 4f 8 5d6s and 4f 7 5d 2 6p. In the case of the Gd II spectrum isotope shifts in the lines of the newly classified transition 4f 8 6s - 4f 8 6p have been studied and isotope shift ΔT (156-160) 87 mK has been obtained for the 4f 8 6s configuration. The other transitions of Gd II involve the odd configurations 4f 7 5d6s, 4f 7 6s 2 , 4f 7 5d 2 and 4f 8 6p and the even ones 4f 7 6s6p, 4f 8 5d, 4f 7 5d6p and 4f 8 6p. The ΔT (156-160) of a large number of odd and even levels of Gd I and Gd II have been evaluated. Electronic configurations have been suggested for a number of energy levels and configuration mixing has been pointed out in certain cases. A number of hitherto unreported transitions have been found and using a monoisotopic sample of Gd, that is 160 Gd, their separations from the closest listed transitions have been measured. (author)

  20. Comparison between immediate and delayed imaging after gadolinium chelate injection for detecting enhanced lesions in multiple sclerosis

    International Nuclear Information System (INIS)

    Alizadeh, A.; Roudbari, A.; Heidarzadeh, A.; Kouhsari, M.

    2010-01-01

    Magnetic resonance imaging is a noninvasive and valuable method in the diagnosis of Multiple Sclerosis. Compared with other modalities, the sensitivity of Magnetic resonance imaging for detection of the lesion increases using magnetization transfer and delayed imaging. Our aim was to compare the two methods in detecting Multiple Sclerosis lesions. Patients and Methods: In this double-blind clinical trial, twenty-one patients with the definite diagnosis of Multiple Sclerosis referred to Poursina Hospital, Rasht were included. Two radiologists evaluated all the images. First, images without contrast were conducted, then 0.1 mmol/kg contrast material (Dotarem, single dose) was injected and after 30 minutes, T1W and magnetization transfer images were obtained. Seventy-two hours later, T1W images were obtained immediately after injection of 0.2 mmol/kg contrast material (double dose). The data were analyzed using Fisher's and McNemar tests by SPSS for Windows. Results: Delayed magnetization transfer showed 44 enhanced lesions using magnetization transfer (69.84%) and 29 lesions using T1 (46.03%). In addition, the number of enhanced lesions in the delayed method were significantly more than those in the immediate method (p value=0.003). Conclusion: The use of single dose in combination with magnetization transfer and delayed images after 20-30 minutes enables us to detect more enhanced lesions.

  1. Increased Uptake of Chelated Copper Ions by Lolium perenne Attributed to Amplified Membrane and Endodermal Damage

    Directory of Open Access Journals (Sweden)

    Anthea Johnson

    2015-10-01

    Full Text Available The contributions of mechanisms by which chelators influence metal translocation to plant shoot tissues are analyzed using a combination of numerical modelling and physical experiments. The model distinguishes between apoplastic and symplastic pathways of water and solute movement. It also includes the barrier effects of the endodermis and plasma membrane. Simulations are used to assess transport pathways for free and chelated metals, identifying mechanisms involved in chelate-enhanced phytoextraction. Hypothesized transport mechanisms and parameters specific to amendment treatments are estimated, with simulated results compared to experimental data. Parameter values for each amendment treatment are estimated based on literature and experimental values, and used for model calibration and simulation of amendment influences on solute transport pathways and mechanisms. Modeling indicates that chelation alters the pathways for Cu transport. For free ions, Cu transport to leaf tissue can be described using purely apoplastic or transcellular pathways. For strong chelators (ethylenediaminetetraacetic acid (EDTA and diethylenetriaminepentaacetic acid (DTPA, transport by the purely apoplastic pathway is insufficient to represent measured Cu transport to leaf tissue. Consistent with experimental observations, increased membrane permeability is required for simulating translocation in EDTA and DTPA treatments. Increasing the membrane permeability is key to enhancing phytoextraction efficiency.

  2. Anthropogenic gadolinium anomalies and rare earth elements in the water of Atibaia River and Anhumas Creek, Southeast Brazil.

    Science.gov (United States)

    de Campos, Francisco Ferreira; Enzweiler, Jacinta

    2016-05-01

    The concentrations of rare earth elements (REE), measured in water samples from Atibaia River and its tributary Anhumas Creek, Brazil, present excess of dissolved gadolinium. Such anthropogenic anomalies of Gd in water, already described in other parts of the world, result from the use of stable and soluble Gd chelates as contrast agents in magnetic resonance imaging. Atibaia River constitutes the main water supply of Campinas Metropolitan area, and its basin receives wastewater effluents. The REE concentrations in water samples were determined in 0.22-μm pore size filtered samples, without and after preconcentration by solid-phase extraction with bis-(2-ethyl-hexyl)-phosphate. This preconcentration method was unable to retain the anthropogenic Gd quantitatively. The probable reason is that the Gd chelates dissociate slowly in acidic media to produce the free ion that is retained by the phosphate ester. Strong correlations between Gd and constituents or parameters associated with effluents confirmed the source of most Gd in water samples as anthropogenic. The shale-normalized REE patterns of Atibaia River and Anhumas Creek water samples showed light and heavy REE enrichment trends, respectively. Also, positive Ce anomalies in many Atibaia River samples, as well as the strong correlations of the REE (except Gd) with terrigenous elements, imply that inorganic colloidal particles contributed to the REE measured values.

  3. Obligatory reduction of ferric chelates in iron uptake by soybeans.

    Science.gov (United States)

    Chaney, R L; Brown, J C; Tiffin, L O

    1972-08-01

    The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

  4. Hepatocellular carcinoma. Comparison between gadolinium and ironoxide enhanced MR imaging

    International Nuclear Information System (INIS)

    Castoldi, M.C.; Fauda, V.; Scaramuzza, D.; Vergnaghi, D.

    2000-01-01

    Purpose of this work is to compare prospectively dynamic gadolinium (Gd)-enhanced with superparamagnetic iron oxide (SPIO)-enhanced MRI for the detection of hepatocellular carcinoma (HCC). Twenty-five patients with histologically proven HCC and liver cirrhosis (28% of them in B or C Child class) underwent dynamic Gd-enhanced MRI and, a few days later, (mean interval: three days) SPIO-enhanced MRI. Only patients with availability of clinical and imaging follow-up for at least seven months were enrolled in this prospective study. MR images were reviewed by two independent radiologists. The readers scored each lesion for the presence of HCC and assigned confidence levels based on a five-grade scale: 1, definitely or almost definitely absent; 2, possibly present; 3, probably present; 4, definitely present; 5, definitely present with optimal liver/lesion contrast or good liver/lesion contrast and morphological signs (intact capsule, intranodular septa, extracapsular infiltration), useful for locoregional treatment planning. A positive diagnostic value was assessed for scores of 3 or higher. Gd-enhanced and SPIO-enhanced MRI found 44 lesions. Eight of twelve lesions visible with a single contrast agent measured less than 1 cm in diameter. HCC detectability was 75% with Gd-enhanced MRI and 97.7% with SPIO-enhanced MRI. SPIO-enhanced T2-weighted TSE images showed significantly higher diagnostic value than SPIO-enhanced T1-T2*GRE images only in three cases, while nodule morphological characteristics (capsule, septa, different cell differentiation components) were better depicted by TSE images. In thi study the combined use of SPIO-enhanced T2-weighted TSE and T1-T2*-weighted GRE sequences showed higher sensitivity than gadolinium-enhanced GRE dynamic imaging (97.7% versus 75%). These results are at least partly related to our study conditions, that is: 1)MRI was performed with a 1T system, 2) both axial and sagittal SPIO-enhanced imaging were performed with respiratory

  5. Chronic Toxic Metal Exposure and Cardiovascular Disease: Mechanisms of Risk and Emerging Role of Chelation Therapy.

    Science.gov (United States)

    Aneni, Ehimen C; Escolar, Esteban; Lamas, Gervasio A

    2016-12-01

    Over the last few decades, there has been a growing body of epidemiologic evidence linking chronic toxic metal exposure to cardiovascular disease-related morbidity and mortality. The recent and unexpectedly positive findings from a randomized, double-blind, multicenter trial of metal chelation for the secondary prevention of atherosclerotic cardiovascular disease (Trial to Assess Chelation Therapy (TACT)) have focused the discussion on the role of chronic exposure to toxic metals in the development and propagation of cardiovascular disease and the role of toxic metal chelation therapy in the secondary prevention of cardiovascular disease. This review summarizes the most recent evidence linking chronic toxic metal exposure to cardiovascular disease and examines the findings of TACT.

  6. Gadolinium-DTPA in magnetic resonance tomography

    International Nuclear Information System (INIS)

    Prayer, L.; Imhof, H.; Stiglbauer, R.; Kramer, J.; Wimberger, D.

    1989-01-01

    Magnetic resonance tomography was performed on 158 patients with different indications before and after the administration of contrast medium. The MR examination included various plain T 1 and T 2 weighted spin echo sequences as well as T 1 weighted examinations after intravenous application of gadolinium-DTPA ('Magnevist', Schering AG) in a dosage of 0.1 mmol/kg body weight. The following conclusions were drawn: The sensitivity of MR in detecting brain tumors, acoustic neuromas and pituitary adenomas was improved considerably after the administration of 'Magnevist'. To diagnose the type of tumor, the criteria which apply to Gd-DPTA are similar to those used for iodine-containing contrast medium in CT. In about 2/3 rds of the cases, delineation of pathological tissues from surrounding edema and normal structures was better than in plain films. Hence, accurate, pretherapeutic staging of bronchial carcinomas and an exact definition of the expansion of the malignancies in the muscle-skeleton system were possible. In respect of tumors in the region of the base of the skull, we could omit T 2 -weighted sequences without noticeable loss of diagnostically relevant information; the examination time could thus be shortened by about 12 minutes. (orig.) [de

  7. Gadolinium Magnetic resonance with a diagnosis of Bell's facial palsy

    International Nuclear Information System (INIS)

    Rovira Canellas, A.; Sanchez Torres, C.; Navarrete, M.; Grive Isern, E.; Capellades Font, J.; Navarrete, M.

    1993-01-01

    The intratemporal pathway of the facial nerve has been prospectively studied by means of gadolinium MR in 12 patients with a diagnosis of Bell's facial palsy. All the cases presented total facial paralysis and were studied in the acute phase of the disease. With MR, the intratemporal pathway of the facial nerve has been viewed before and after the administration of a paramagnetic contrast medium, revealing uptake involving mainly the labyrinthine segment and the geniculate ganglion in every case. In no case did the MR findings influence the therapeutic approach, nor did they provide information of prognostic value. Therefore, this exploration is not considered necessary in the assessment of typical facial paralyses. The possible advantages of an MR study with contrast medium in facial paralysis specially apply to those cases with atypical clinical presentation, making it possible to establish a positive diagnosis, ruling out other lesions that may have a similar clinical presentantion. Thus, for the time being, a diagnosis of Bell's paralysis is not necessarily an exclusion diagnosis. (Author)

  8. Gadolinium-enhanced MR imaging in evaluation of cholesteatoma

    International Nuclear Information System (INIS)

    Sugihara, M.; Sugimura, K.; Ishida, T.; Fujino, A.; Miyakuni, Y.

    1990-01-01

    It was sometimes difficult to differentiate cholesteatoma from accompanied granuloma, cholesterol granuloma, or mastoiditis on high-resolution CT. This study was designed to assess the reliability with which cholesteatoma can be differentiated from those accompanied lesions by gadolinium-enhanced MR imaging. Eight patients suspected to have cholesteatoma were evaluated with GD-DTPA-enhanced MR imaging with a 1.5-T MR imaging GE Signa unit. axial pre- and postcontrast T1-weighted (TR/TE, 600/20) and T2-weighted (TR/TE, 2,000/70) images were studied. MR imaging findings were compared with histologic findings (13 lesions), which included cholesteatoma (n = 6), granuloma (n = 4), cholesterol granuloma (n = 2), and mastoiditis (n = 1). Cholesteatoma had an intermediate to high signal intensity (SI) similar to that of granuloma on both T1- and T2-weighted images. Cholesterol granulomas showed high SI on both T1- and T2-weighted images. Mastoiditis demonstrated marked high SI on T2-weighted images. Cholesterol granuloma and mastoiditis can be distinguished from cholesteatoma or granuloma on both T1- and T2-weighted images. On Gd-DTPA-enhanced images, there was marked enhancement of all granulomas. However, no cholesteatoma enhancement was seen in all six lesions. Gd-DTPA-enhanced images were able to distinguish cholesteatoma from granuloma and to estimate the exact extent of cholesteatoma. Gd-DTPA-enhanced MR imaging is valuable in the evaluation and management of cholesteatoma

  9. Decorporation of metal ions by chelating agents

    International Nuclear Information System (INIS)

    Koenig, T.

    1978-01-01

    Simple model designs to simulate the effect of therapeutical chelating agents on the behaviour of metals in mammal organisms with and without excretion have been derived and analytical solutions given for the corresponding differential equations. The possibilities of these models in the short-term description of plasma kinetics of various metals, the competition of the therapeutical ligands with proteins for the metal and of the metabolism of chelating agents were tested and the properties applying extreme conceivable parameters were analyzed. The simple models were successsively expanded in logical sequence, so that it was possible to qualitatively well describe over a long period of time, the metallic kinetics in plasma, organs and urine, the retention of the ligands and their effect on the metal excretion. Two suggestions were given to describe the so-called after-effect, an increased excretion of the metal at times when the ligand is almost completely excreted and their different behaviour after injecting the metal chelate is given. Calculations on the therapy with several ligand data as well as on dose fractionation are described resting on the ratios in the plutonium-239 chosen model parameters and the determining mechanisms analyzed. (orig./MG) [de

  10. IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

    Directory of Open Access Journals (Sweden)

    Paolo Cianciulli

    2009-06-01

    Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

  11. Extraction of gadolinium from high flux isotope reactor control plates

    International Nuclear Information System (INIS)

    Kohring, M.W.

    1987-04-01

    Gadolinium-153 is an important radioisotope used in the diagnosis of various bone disorders. Recent medical and technical developments in the detection and cure of osteoporosis, a bone disease affecting an estimated 50 million people, have greatly increased the demand for this isotope. The Oak Ridge National Laboratory (ORNL) has produced 153 Gd since 1980 primarily through the irradiation of a natural europium-oxide powder followed by the chemical separation of the gadolinium fraction from the europium material. Due to the higher demand for 153 Gd, an alternative production method to supplement this process has been investigated. This process involves the extraction of gadolinium from the europium-bearing region of highly radioactive, spent control plates used at the High Flux Isotope Reactor (HFIR) with a subsequent re-irradiation of the extracted material for the production of the 153 Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (≥60% enriched in 152 Gd) resides in the europium-bearing region of the HFIR control components of which 70% is recoverable. At a specific activity yield of 40 curies of 153 Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed

  12. Impact of educational programme regarding chelation therapy on the quality of life for B-thalassemia major children.

    Science.gov (United States)

    Abu Samra, Omayma; Auda, Wafaa; Kamhawy, Heba; Al-Tonbary, Youssef

    2015-06-01

    Objectives Thalassemia is the most common genetic disorder in Egypt, with an estimated carrier rate of 9-10%. It is a genetic blood disorder which can be fatal if proper chelation is not received. The introduction of chelating agents capable of removing excessive iron from the body has dramatically increased life expectancy and improved the overall quality of life. The aim of this study was to assess the impact of educational programmes regarding chelation therapy on the quality of life of thalassemic children. Methods The study was carried out at the Mansoura University Children's Hospital in the period between March 2010 and May 2011. It included 173 B-thalassemia children (84 boys and 89 girls) with age ranging between 8-18 years. The researcher used a predesigned interviewing questionnaire to collect data regarding children's knowledge about thalassemia and its management, especially regarding chelation therapy. The paediatric quality-of-life inventory tool (Peds QL 4.0 generic core) was also used to assess the studied children's quality of life. Results There was a significant statistical difference of the studied children's knowledge regarding chelation therapy and their quality of life. Conclusion There was a positive effect of the educational programme in improving children's knowledge score and their quality of life. Application of educational programmes for thalassemic children and their nurses regarding chelation therapy and its importance in preventing thalassemia complications is established.

  13. Comparison of gadolinium Cy2DOTA, a new hepatobiliary agent, and gadolinium HP-DO3A, an extracellular agent, in healthy liver and metastatic disease

    International Nuclear Information System (INIS)

    Runge, V.M.; Wells, J.W.; Williams, N.M.

    1995-01-01

    A new gadolinium (Gd) chelate with preferential hepatobiliary uptake, Gd Cy 2 DOTA, was compared in two animal species with Gd HP-DO3A (gadoteridol), a clinically approved contrast agent with extracellular distribution. Liver enhancement was evaluated for these two contrast agents using magnetic resonance imaging, whereas an experimental model of metastatic disease was used to evaluate the agents' efficacy for liver-lesion delineation. The two agents were compared in four healthy Rhesus monkeys (eight studies) and five New Zealand White rabbits with implanted VX-2 liver tumors (ten studies). The contrast dose was 0.1 mmol/kg, with the agents given in random order and at least 72 hours between contrast injections. Breathhold T1-weighted spin echo scans were obtained at 1.5 tesla (T) before and after contrast was administered. Postcontrast scans were obtained 1 to 90 minutes after injection in the monkeys and 1 to 240 minutes after injection in the rabbits. Prolonged hepatic enhancement, superior in degree to that with Gd HP-DO3A, was noted to both monkeys and rabbits after injection of Gd Cy 2 DOTA. Two minutes after contrast, liver SI was 1.94 ± 0.05 with Gd Cy 2 DOTA compared with 1.5 ± 0.05 with Gd HP-DO3A in monkeys. Sixty minutes after contrast, liver SI was 1.60 ± 0.09 compared with 1.20 ± 0.02. The difference between agents was significant at all times from 2 to 60 minutes after contrast injection (P 2 DOTA but not with Gd HP-DO3A. The maximum improvement in lesion conspicuity (rabbit) occurred 45 minutes after injection of Gd Cy 2 DOTA and 5 minutes after injection of Gd HP-DO3A. 22 refs., 12 figs

  14. Nature of the bifunctional chelating agent used for radioimmunotherapy with yttrium-88 monoclonal antibodies: critical factors in determining in vivo survival and organ toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, R.W.; Raubitschek, A.; Mirzadeh, S.; Brechbiel, M.W.; Junghaus, R.; Gansow, O.A.; Waldmann, T.A. (Center for Biologics Evaluation and Research, FDA, Bethesda, MD (USA))

    1989-05-15

    One factor that is critical to the potential effectiveness of radioimmunotherapy is the design of radiometal-chelated antibodies that will be stable in vivo. Stability in vivo depends on the condition that both the chelate linkage and radiolabeling procedures not alter antibody specificity and biodistribution. In addition, synthesis and selection of the chelating agent is critical for each radiometal in order to prevent inappropriate release of the radiometal in vivo. In the present study, we compare the in vivo stability of seven radioimmunoconjugates that use different polyaminocarboxylate chelating agents to complex yttrium-88 to the mouse anti-human interleukin-2 receptor monoclonal antibody, anti-Tac. Chelate linkage and radiolabeling procedures did not alter the immunospecificity of anti-Tac. In order to assess whether yttrium was inappropriately released from the chelate-coupled antibody in vivo, iodine-131-labeled and yttrium-88 chelate-coupled antibodies were simultaneously administered to the same animals to correlate the decline in yttrium and radioiodinated antibody activity. The four stable yttrium-88 chelate-coupled antibodies studied displayed similar iodine-131 and yttrium-88 activity, indicating minimal elution of yttrium-88 from the complex. In contrast, the unstable yttrium-88 chelate-coupled antibodies had serum yttrium-88 activities that declined much more rapidly than their iodine-131 activities, suggesting loss of the radiolabel yttrium-88 from the chelate. Furthermore, high rates of yttrium-88 elution correlated with deposition in bone. Four chelating agents emerged as promising immunotherapeutic reagents: isothiocyanate benzyl DTPA and its derivatives 1B3M, MX, and 1M3B.

  15. Chemical aspects of gadolinium nitrate as soluble nuclear poison in Savannah River Plant reactors

    International Nuclear Information System (INIS)

    Baumann, E.W.

    1978-01-01

    The aqueous solution chemistry of gadolinium nitrate was studied to identify conditions that interfere with successful cleanup of gadolinium in Savannah River Plant reactor systems. Injecting a gadolinium nitrate solution into the D 2 O coolant-moderator constitutes a supplementary mode of reactor shutdown. The resulting approximately 0.001M gadolinium nitrate solution is then deionized by recirculation through mixed-bed ion exchange resins before reactor operation is resumed

  16. Selective photoionization of gadolinium isotopes with a polarized laser

    International Nuclear Information System (INIS)

    Le Guyadec, E.

    1990-06-01

    The aim of this study is the use of gadolinium 157 as burnable poison in nuclear reactors. Spectroscopic isotopic displacements between Gd 156 and Gd 157 are low and the separation method studied is based on differentiated behavior, concerning polarized light, of even and odd gadolinium isotopes coming from their difference of nuclear spin. On this principle is based the simplest photoionization scheme. Selective ionization of odd isotopes is realized from the fundamental state with three resonating photons colinearly polarized. The experimental study confirms the possibility of efficient photoionization. The measured selectivity between Gd 157 and even isotope is over 48 in defined conditions because it can be destroyed by a magnetic field or if photons are not well polarized. Calculations and observations are in good agreement. Odd gadolinium isotope separation is feasible and effects preventing separation are evidenced [fr

  17. performance calculations of gadolinium oxide and boron nitride coated fuel

    International Nuclear Information System (INIS)

    Tanker, E.; Uslu, I.; Disbudak, H.; Guenduez, G.

    1997-01-01

    A comparative study was performed on the behaviour of natural uranium dioxide-gadolinium oxide mixture fuel and boron nitride coated low enriched fuel in a pressurized water reactor. A fuel element containing one burnable poison fuel pins was modeled with the computer code WIMS, and burn-up dependent critically, fissile isotope inventory and two dimensional power distribution were obtained. Calculations were performed for burnable poison fuels containing 5% and 10% gadolinium oxide and for those coated with 1μ,5μ and 10μ of boron nitride. Boron nitride coating was found superior to gadolinium oxide on account of its smoother criticality curve, lower power peaks and insignificant change in fissile isotope content

  18. Magnetic resonance ventriculography with gadolinium DTPA: report of two cases

    International Nuclear Information System (INIS)

    Siebner, H.R.; Einsiedel, H. von; Conrad, B.

    1997-01-01

    We report intrathecal use of gadolinium DTPA for MRI of the cerebrospinal fluid (CSF). In two patients with leptomeningeal carcinomatosis, we injected 0.01 mmol gadolinium DTPA into the lateral ventricle via an Ommaya device. Coronal T1-weighted images of the head were obtained at 0.2 T prior to and after injection. There was pronounced enhancement of CSF close to the injection site, allowing good delineation of CSF and surrounding brain tissue. No side effects occurred. MRI with intrathecal administration of highly diluted gadolinium DTPA may be a promising alternative to conventional investigation of CSF-filled cavities using iodinated X-ray contrast media or radionuclides. (orig.). With 3 figs

  19. Mixed ligand chelates of rare earths in aqueous solution

    International Nuclear Information System (INIS)

    Lakhani, S.U.; Thakur, G.S.; Sangal, S.P.

    1981-01-01

    Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10 4 . The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

  20. Use of gadolinium as neutron poison in 540 MWe PHWR

    International Nuclear Information System (INIS)

    Nag, P.K.; Fernando, M.P.S.; Kumar, A.N.

    2006-01-01

    In Pressurised heavy water reactors (PHWRs), neutron poison in the moderator is used to compensate the excess reactivity present in the core on different occasions such as xenon decay during synchronization just after poison out period or start ups from xenon free conditions. It is also used in secondary shutdown system (SDS-2), where required amount of neutron poison is injected directly into the moderator within 2.5 seconds. Further, it is also used for over poisoning the moderator to achieve the guaranteed shutdown state when the regular shutdown systems are taken for maintenance. Generally, two types of moderator poisons are used in power reactors to balance the reactivity of the core and they are boron and gadolinium. Gadolinium is used in the form of gadolinium nitrate (Gd(NO 3 ) 3 .6H 2 O). The paper gives the details of estimation of reactivity coefficients of gadolinium for 540 MWe PHWR for different operating conditions. These neutron poisons are converted into non-absorbing elements and therefore their effective worth will decrease as reactor operation proceeds. The rate of burning of neutron absorbing isotopes depends on its magnitude of absorption cross-section and thermal flux seen by them. The present study discusses the burning characteristics of gadolinium during power operation in 540 MWe PHWR. It is established by detailed analysis that the rate of positive reactivity realized due to burning of neutron absorbing Gd isotopes almost match with the build up rate of xenon. The burning half lives of boron and gadolinium is worked out for different power levels. (author)

  1. Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

    Science.gov (United States)

    Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

    2018-06-01

    The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

  2. Study on the thermodynamics of the gadolinium-hydrogen binary system (H/Gd = 0.0–2.0) and implications to metallic gadolinium purification

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Kai; Li, Guoling [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Jigang [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Liu, Yang [Department of Food Science, College of Arts and Science, Beijing Union University, Beijing, 100101 (China); Tian, Wenhuai, E-mail: wenhuaitian@ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Zheng, Jie [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Li, Xingguo, E-mail: xgli@pku.edu.cn [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2016-07-15

    The thermodynamics of the gadolinium-hydrogen (Gd–H) binary system (H/Gd = 0.0–2.0) between 650 and 900 °C is studied by pressure composition isotherm measurement. Significant H dissolution in Gd is observed, up to H/Gd = 0.34 at 650 °C and 0.55 at 900 °C. The metal-rich phase boundary of nonstoichiometric gadolinium dihydride was found to occur with nominal composition of GdH{sub 1.80} at 650 °C and GdH{sub 1.53} at 900 °C. The results are in fairly good agreement with previous experimental work but with improved accuracy. The binary phase diagram is obtained using the CALPHAD method. The thermodynamic study here assists the understanding on the efficient deoxygenation effect by the H in Gd for Gd purification. - Highlights: • PCI measurements with high accuracy has been carried out. • A first assessment of Gd–H system has been carried out by the CALPHAD method. • A set of self-consistent thermodynamic parameters was derived for this system.

  3. Gadolinium-based contrast agents in pediatric magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gale, Eric M.; Caravan, Peter [Massachusetts General Hospital, Harvard Medical School, Department of Radiology, The Martinos Center for Biomedical Imaging, Boston, MA (United States); Rao, Anil G. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); McDonald, Robert J. [College of Medicine, Mayo Clinic, Department of Radiology, Rochester, MN (United States); Winfeld, Matthew [University of Pennsylvania Perelman School of Medicine, Philadelphia, PA (United States); Fleck, Robert J. [Cincinnati Children' s Hospital Medical Center, Department of Pediatric Radiology, Cincinnati, OH (United States); Gee, Michael S. [MassGeneral Hospital for Children, Harvard Medical School, Division of Pediatric Imaging, Department of Radiology, Boston, MA (United States)

    2017-05-15

    Gadolinium-based contrast agents can increase the accuracy and expediency of an MRI examination. However the benefits of a contrast-enhanced scan must be carefully weighed against the well-documented risks associated with administration of exogenous contrast media. The purpose of this review is to discuss commercially available gadolinium-based contrast agents (GBCAs) in the context of pediatric radiology. We discuss the chemistry, regulatory status, safety and clinical applications, with particular emphasis on imaging of the blood vessels, heart, hepatobiliary tree and central nervous system. We also discuss non-GBCA MRI contrast agents that are less frequently used or not commercially available. (orig.)

  4. Physical and chemical properties of calcium doped gadolinium cobaltite

    International Nuclear Information System (INIS)

    Zhuk, P.P.; Kharton, V.V.; Tonoyan, A.A.; Naumovich, E.N.

    1991-01-01

    The effect of calcium doping additions on electrical and tharmal properties of gadolinium cobaltite was investigated. It was established that solid solutions of Gd 1-x Ca x CoO 3 (x=0-0.5) composition had cubic perovskite structure with orthorhombic distortion. Calcium doping of gadolinium cobaltite increases its conductivity by two orders. Parameter of resistance of electronic layer of ρ/d for a sample of Gd 0.9 Ca 0.1 CoO 3 composition at d≥40mg/sm 2 was by an order higher than in compact samples

  5. The obtaining a high-grade gadolinium concentrate

    International Nuclear Information System (INIS)

    Soltysiak, I.; Ozga, W.

    1982-01-01

    Gadolinium concentrates obtained by the fractional precipitation of lanthanon-potassium double chromates were separated by ion exchange with 0,4 M lactic acid solution in the presence of 0,1 M ammonium nitrate at pH of the medium 2,95-3,4. It was found out, that using the fractional precipitation of lanthanon-potassium double chromates (as the fast and cheap method that does not need special equipment) together with ion exchange separation with lactic acid solution as the eluent gave a highgrade gadolinium concentrate in a quick and economical way. (author)

  6. Glioblastoma, gadolinium (III) and NCT. An in vitro study

    International Nuclear Information System (INIS)

    Mercanti, D.; Casalbore, P.; Sanita, F.; Rosi, F.; Festinesi, A.; Pallini, R.; Gilbert, B.; Stasio, G. de

    2000-01-01

    We treated cultured human glioblastoma cells with gadolinium (III) [gadopentetic acid] and we found that: a) cells do internalise this element; b) gadolinium can be localised in the cells nuclei; c) exposure of the cultures to a neutron beam produced a significant and immediate cell death. Although cell survival was also influenced in the irradiated controls it was further reduced (about 50%) in cells pre-exposed to 10 mg/ml gadopentetic acid. We also found that Gd uptake, as measured by ICP-AES, was concentration dependent. (author)

  7. Gadolinium-enhanced MR angiography of the thoracoabdominal aorta diseases

    International Nuclear Information System (INIS)

    D'Ippolito, Giuseppe; Wolosker, Nelson; Galvao Filho, Mario; Kalil, Jorge A.; Wolosker, Angela; Borri, Maria Lucia

    1998-01-01

    Gadolinium-enhanced MR angiography (GEMRA) of the thoracoabdominal aorta is a noninvasive technique that can rapidly delineate the branch vessels diseases, without flow or respiration artifacts, obtained with non contrast MRA. The objective of this paper is to show the main clinical applications of GEMRA, compared to non contrast sequences. We have evaluated 30 patients with thorocoabdominal aorta diseases. These patients have been examined with GEMRA (3D, FFE sequences) obtained after 30 mlIV contrast injection and non contrast MRA (2D-TOF sequences). In our experience, gadolinium-enhanced MRA is a high resolution and speedy technique with advantages over non contrast MRA. (author)

  8. The effect of demagnetization on the magnetocaloric properties of gadolinium

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Nielsen, Kaspar Kirstein

    2009-01-01

    of gadolinium. The adiabatic temperature change DeltaTad of gadolinium sheets upon application of a magnetic field has been measured at a range of applied magnetic fields and sample orientations. A significant dependence of DeltaTad on the sample orientation is observed. This can be accounted...... for by the demagnetization factor. Also, the temperature dependence of DeltaTad has been measured experimentally and modeled by mean field theory. Corrections to mean field theory modeling due to the demagnetization field are proposed and discussed. ©2009 American Institute of Physics...

  9. Leach studies of chelating agents and influence on radionuclide leaching from simulated LLW/ILW cement waste forms

    International Nuclear Information System (INIS)

    Vejmelka, P.; Koester, R.; Ferrara, D.; Wacks, M.E.

    1990-01-01

    Leach studies were performed on cemented waste forms containing sodium nitrate, trace amounts of cesium-137, and cobalt-60, and a chelating agent (ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), or citric acid). Leaching of the chelates was measured in water and the effect of the chelates on the release of the Cs-137 and Co-60 was studied. The time dependence of the release rate of the chelates is comparable but the chelate concentration in solution and the released fractions are different. EDTA shows the highest release rate followed by NTA and citrate. The release of the non complex forming cesium is not affected by the presence of the chelates. Independent from the strong complex formation of cobalt with EDTA, NTA, and citrate in the alkaline region the cobalt release is also not affected by the presence of the chelates. The high calcium content of the system decreases the stability of the Co complexes in the high pH region (12-13). Experiments were performed to determine the equilibrium concentration of the chelates between liquid and solid phases. The liquid phases were deionized water, saturated sodium chloride, 24 percent magnesium chloride and Q-brine. The equilibrium studies are based on the assumption that in time a stable final condition is to be established in the near field of the waste form in which each compound is at chemical equilibrium between the dissolved and the various solid phases. The total release may be assessed from the concentration in solution and flow rate out of the near field. The fraction of EDTA released from the cement ranged from 0.2 in the Q-brine to 0.5 in the saturated sodium chloride. The concentration of EDSA in solution was dependent on the original amount in the cement sample, but the released fraction was independent of the initial loading. Indicating, EDTA concentration is not affected by solubility limits. 11 refs., 3 figs., 2 tabs

  10. Metal regeneration of iron chelates in nitric oxide scrubbing

    Science.gov (United States)

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  11. Cell-permeable Ln(III) chelate-functionalized InP quantum dots as multimodal imaging agents.

    Science.gov (United States)

    Stasiuk, Graeme J; Tamang, Sudarsan; Imbert, Daniel; Poillot, Cathy; Giardiello, Marco; Tisseyre, Céline; Barbier, Emmanuel L; Fries, Pascal Henry; de Waard, Michel; Reiss, Peter; Mazzanti, Marinella

    2011-10-25

    Quantum dots (QDs) are ideal scaffolds for the development of multimodal imaging agents, but their application in clinical diagnostics is limited by the toxicity of classical CdSe QDs. A new bimodal MRI/optical nanosized contrast agent with high gadolinium payload has been prepared through direct covalent attachment of up to 80 Gd(III) chelates on fluorescent nontoxic InP/ZnS QDs. It shows a high relaxivity of 900 mM(-1) s(-1) (13 mM(-1 )s(-1) per Gd ion) at 35 MHz (0.81 T) and 298 K, while the bright luminescence of the QDs is preserved. Eu(III) and Tb(III) chelates were also successfully grafted to the InP/ZnS QDs. The absence of energy transfer between the QD and lanthanide emitting centers results in a multicolor system. Using this convenient direct grafting strategy additional targeting ligands can be included on the QD. Here a cell-penetrating peptide has been co-grafted in a one-pot reaction to afford a cell-permeable multimodal multimeric MRI contrast agent that reports cellular localization by fluorescence and provides high relaxivity and increased tissue retention with respect to commercial contrast agents.

  12. Relationship among chelator adherence, change in chelators, and quality of life in thalassemia.

    Science.gov (United States)

    Trachtenberg, Felicia L; Gerstenberger, Eric; Xu, Yan; Mednick, Lauren; Sobota, Amy; Ware, Hannah; Thompson, Alexis A; Neufeld, Ellis J; Yamashita, Robert

    2014-10-01

    Thalassemia, a chronic blood disease, necessitates life-long adherence to blood transfusions and chelation therapy to reduce iron overload. We examine stability of health-related quality of life (HRQOL) in thalassemia and adherence to chelation therapy over time, especially after changes in chelator choice. Thalassemia Longitudinal Cohort participants in the USA, UK, and Canada completed the SF-36v2 (ages 14+) and the PF-28 CHQ (parents of children health status) at baseline who made a single change in chelator, but declined among participants with multiple changes and/or high iron burden (worse health status). Mental health improved among participants with lower iron burden, but iron overload was negatively associated with social functioning. Adherence did not significantly change over follow-up except for an increase after a change from deferoxamine (DFO) infusion to oral deferasirox (p = 0.03). Predictors of lower adherence for adults/adolescents at follow-up included side effects, smoking, younger age, problems preparing DFO, increased number of days per week DFO prescribed, and lower physical quality of life . Strategies to balance medical needs with family, work, and personal life may assist in adherence.

  13. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    International Nuclear Information System (INIS)

    Zhang, Fan; Huang, Xinglu; Qian, Chunqi; Zhu, Lei; Hida, Naoki; Niu, Gang; Chen, Xiaoyuan

    2012-01-01

    Highlights: ► MR contrast agents exert influence on T 1 or T 2 relaxation time of the surrounding tissue. ► Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. ► Dual contrast MRI enhances the delineation of tumor borders and small lesions. ► The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd 3+ . ► The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T 1 ) or transverse (T 2 ) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T 2 weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T 2 relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to −4.12 ± 0.71. Dual contrast MRI also enhanced the delineation of tumor borders and small lesions. Conclusions: DC-MRI will be helpful to improve diagnostic accuracy and decrease the threshold size for

  14. Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement

    Directory of Open Access Journals (Sweden)

    Scott D Swanson

    2008-06-01

    Full Text Available Scott D Swanson1, Jolanta F Kukowska-Latallo2, Anil K Patri5, Chunyan Chen6, Song Ge4, Zhengyi Cao3, Alina Kotlyar3, Andrea T East7, James R Baker31Department of Radiology, The University of Michigan Medical School, 2Department of Internal Medicine, The University of Michigan Medical School, 3Michigan Nanotechnology Institute for Medicine and Biological Sciences, The University of Michigan, 4Applied Physics, The University of Michigan, MD, USA; 5Present address: National Cancer Institute at Frederick (Contractor, MD, USA; 6Present address: Intel Corporation, Chandler, AZ, USA; 7Present address: Stritch School of Medicine, Chicago, ILL, USAAbstract: A target-specific MRI contrast agent for tumor cells expressing high affinity folate receptor was synthesized using generation five (G5 of polyamidoamine (PAMAM dendrimer. Surface modified dendrimer was functionalized for targeting with folic acid (FA and the remaining terminal primary amines of the dendrimer were conjugated with the bifunctional NCS-DOTA chelator that forms stable complexes with gadolinium (Gd III. Dendrimer-DOTA conjugates were then complexed with GdCl3, followed by ICP-OES as well as MRI measurement of their longitudinal relaxivity (T1 s−1 mM−1 of water. In xenograft tumors established in immunodeficient (SCID mice with KB human epithelial cancer cells expressing folate receptor (FAR, the 3D MRI results showed specific and statistically significant signal enhancement in tumors generated with targeted Gd(III-DOTA-G5-FA compared with signal generated by non-targeted Gd(III-DOTA-G5 contrast nanoparticle. The targeted dendrimer contrast nanoparticles infiltrated tumor and were retained in tumor cells up to 48 hours post-injection of targeted contrast nanoparticle. The presence of folic acid on the dendrimer resulted in specific delivery of the nanoparticle to tissues and xenograft tumor cells expressing folate receptor in vivo. We present the specificity of the dendrimer

  15. Use of gadolinium-based magnetic resonance imaging contrast agents and awareness of brain gadolinium deposition among pediatric providers in North America

    International Nuclear Information System (INIS)

    Mithal, Leena B.; Patel, Payal S.; Mithal, Divakar; Palac, Hannah L.; Rozenfeld, Michael N.

    2017-01-01

    Numerous recent articles have reported brain gadolinium deposition when using linear but not macrocyclic gadolinium-based contrast agents (GBCAs). To determine the current landscape of gadolinium use among pediatric institutions and the knowledge base of radiologists and referring providers with regard to GBCAs and brain gadolinium deposition. We e-mailed voluntary closed surveys to 5,390 physicians in various pediatric professional societies between January 2016 and March 2016. We used chi-square and Fisher exact tests to compare response distributions among specialties. We found that 80% of surveyed pediatric hospitals use macrocyclic contrast agents. In the last year, 58% switched their agent, most commonly to gadoterate meglumine, with the most common reason being brain gadolinium deposition. Furthermore, surveys indicated that 23% of hospitals are considering switching, and, of these, 83% would switch to gadoterate meglumine; the most common reasons were brain gadolinium deposition and safety. Radiologists were more aware of brain gadolinium deposition than non-radiologist physicians (87% vs. 26%; P<0.0001). Radiologists and referring providers expressed similar levels of concern (95% and 89%). Twelve percent of radiologists and 2% of referring providers reported patients asking about brain gadolinium deposition. Radiologists were significantly more comfortable addressing patient inquiries than referring pediatric physicians (48% vs. 6%; P<0.0001). The number of MRIs requested by referring pediatric physicians correlated with their knowledge of brain gadolinium deposition, contrast agent used by their hospital, and comfort discussing brain gadolinium deposition with patients (P<0.0001). Since the discovery of brain gadolinium deposition, many pediatric hospitals have switched to or plan to switch to a more stable macrocyclic MR contrast agent, most commonly gadoterate meglumine. Despite this, there is need for substantial further education of radiologists and

  16. Use of gadolinium-based magnetic resonance imaging contrast agents and awareness of brain gadolinium deposition among pediatric providers in North America

    Energy Technology Data Exchange (ETDEWEB)

    Mithal, Leena B. [Northwestern University, Feinberg School of Medicine, Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Pediatrics, Chicago, IL (United States); Patel, Payal S. [University of Arizona College of Medicine, Department of Pediatrics, Phoenix, AZ (United States); Mithal, Divakar [Northwestern University, Feinberg School of Medicine, Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Pediatric Neurology, Chicago, IL (United States); Palac, Hannah L. [Northwestern University, Biostatistics, Feinberg School of Medicine, Ann and Robert H. Lurie Children' s Hospital of Chicago, Chicago, IL (United States); Rozenfeld, Michael N. [University of Arizona College of Medicine, Department of Radiology, Phoenix, AZ (United States)

    2017-05-15

    Numerous recent articles have reported brain gadolinium deposition when using linear but not macrocyclic gadolinium-based contrast agents (GBCAs). To determine the current landscape of gadolinium use among pediatric institutions and the knowledge base of radiologists and referring providers with regard to GBCAs and brain gadolinium deposition. We e-mailed voluntary closed surveys to 5,390 physicians in various pediatric professional societies between January 2016 and March 2016. We used chi-square and Fisher exact tests to compare response distributions among specialties. We found that 80% of surveyed pediatric hospitals use macrocyclic contrast agents. In the last year, 58% switched their agent, most commonly to gadoterate meglumine, with the most common reason being brain gadolinium deposition. Furthermore, surveys indicated that 23% of hospitals are considering switching, and, of these, 83% would switch to gadoterate meglumine; the most common reasons were brain gadolinium deposition and safety. Radiologists were more aware of brain gadolinium deposition than non-radiologist physicians (87% vs. 26%; P<0.0001). Radiologists and referring providers expressed similar levels of concern (95% and 89%). Twelve percent of radiologists and 2% of referring providers reported patients asking about brain gadolinium deposition. Radiologists were significantly more comfortable addressing patient inquiries than referring pediatric physicians (48% vs. 6%; P<0.0001). The number of MRIs requested by referring pediatric physicians correlated with their knowledge of brain gadolinium deposition, contrast agent used by their hospital, and comfort discussing brain gadolinium deposition with patients (P<0.0001). Since the discovery of brain gadolinium deposition, many pediatric hospitals have switched to or plan to switch to a more stable macrocyclic MR contrast agent, most commonly gadoterate meglumine. Despite this, there is need for substantial further education of radiologists and

  17. The fate of Gd and chelate following intravenous injection of gadodiamide in rats

    International Nuclear Information System (INIS)

    Moerk Kindberg, Grete; Uran, Steinar; Friisk, Grete; Martinsen, Ivar; Skotland, Tore

    2010-01-01

    The biodistribution of gadolinium (Gd) and chelate was studied in rats injected intravenously with a commercially available gadodiamide magnetic resonance contrast agent spiked with trace amounts of 14 C-labelled GdDTPA-BMA. Biodistribution of the 14 C-labelled ligand in whole animals was visualised using quantitative whole-body autoradiography, and quantified in individual tissue samples by analysing for radioactivity using beta-counting. Biodistribution of Gd was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). The injected dose was rapidly excreted, with only 1.0% remaining in the body at 24 h. The radioactivity thereafter was mainly associated with kidney cortex, liver, lung, muscle and skin, with a similar rate of clearance for both ligand and Gd from these tissues. The ratio between 14 C-labelled substance and Gd was not significantly different from that of the injected substance in most tissue samples up to 24 h after injection; the ratio then slowly decreased. The data clearly show that measurements of Gd concentration alone in tissue samples from animals injected with Gd-based contrast agents (GBCAs) cannot be used as a measure of Gd released from the ligand. To our knowledge, such measurements comparing Gd and ligand concentrations and distribution in tissue samples have not been published previously for any of the commercial GBCAs. (orig.)

  18. Investigation of a potential macromolecular MRI contrast agent prepared from PPI (G = 2, polypropyleneimine, generation 2) dendrimer bifunctional chelates

    Science.gov (United States)

    Wang, Jianxin Steven

    The long-term objective is to develop magnetic resonance (MR) contrast agents that actively and passively target tumors for diagnosis and therapy. Many diagnostic imaging techniques for cancer lack specificity. A dendrimer based magnetic resonance imaging contrast agent has been developed with large proton relaxation enhancements and high molecular relaxivities. A new type of linear dendrimer based MRI contrast agent that is built from the polypropyleneimine and polyamidoamine dendrimers in which free amines have been conjugated to the chelate DTPA, which further formed the complex with Gadolinium (Gd) was studied. The specific research goals were to test the hypothesis that a linear chelate with macromolecular agents can be used in vitro and in vivo. This work successfully examined the adequacy and viability of the application for this agent in vitro and in vivo. A small animal whole body counter was designed and constructed to allow us to monitor biodistribution and kinetic mechanisms using a radioisotope labeled complex. The procedures of metal labeling, separation and purification have been established from this work. A biodistribution study has been performed using radioisotope induced organ/tissue counting and gamma camera imaging. The ratio of percentage of injected dose per gram organ/tissue for kidney and liver is 3.71 from whole body counter and 3.77 from the gamma camera. The results suggested that retention of Gd (III) is too high and a more kinetically stable chelate should be developed. The pharmacokinetic was evaluated in the whole animal model with the whole body clearance, and a kinetics model was developed. The pharmacokinetic results showed a bi-exponential decay in the animal model with two component excretion constants 1.43e(-5) and 0.0038511, which give half-lives of 3 hours and 33.6 days, respectively. Magnetic resonance imaging of this complex resulted in a 52% contrast enhancement in the rat kidney following the agents' administration in

  19. Importance of the use of gadolinium in neurocysticercosis diagnosis

    International Nuclear Information System (INIS)

    Machado Junior, M.A.; Costa, G.; Barbosa, V.A.; Rubin, J.C.

    1994-01-01

    Magnetic Resonance (MRI) and Computed Tomography (CT) features of neurocysticercosis are variable and depend fundamentally on the stage in evolution of the infection, location, number and size of the cysts. The authors retrospectively evaluated MRI obtained on O.5 Tesla superconducting unit in four neurocysticercosis patients and observed new MRI features only after Gadolinium enhancement. (author)

  20. Purification of cerium, neodymium and gadolinium for low background experiments

    Directory of Open Access Journals (Sweden)

    Boiko R.S.

    2014-01-01

    Full Text Available Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search, 136Ce (2β+ candidate with one of the highest Q2β. The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  1. Standard specification for sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification is for finished sintered gadolinium oxide-uranium dioxide pellets for use in light-water reactors. It applies to gadolinium oxide-uranium dioxide pellets containing uranium of any 235U concentration and any concentration of gadolinium oxide. 1.2 This specification recognizes the presence of reprocessed uranium in the fuel cycle and consequently defines isotopic limits for gadolinium oxide-uranium dioxide pellets made from commercial grade UO2. Such commercial grade UO2 is defined so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated uranium. UO2 falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel fabrication plant or in the fuel design. 1.3 This specification does not include (1) provisions for preventing criticality accidents or (2) requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aw...

  2. Kinetics of zigzag domain boundaries in gadolinium molybdate

    International Nuclear Information System (INIS)

    Alekseev, A.N.; Proklov, A.L.; Tikhomirova, N.A.; Shuvalov, L.A.; AN SSSR, Moscow. Inst. Kristallografii)

    1987-01-01

    Kinetics of zigzag domain boundaries (3DB) in ferroelectric gadolinium molybdate (GMO) crystal was investigated at different amplitude, duration and growth rate of external electric field. The results verify the difference between shifting rates of two 3DB constituents of wedge-shaped systems, growing with field change rate increase

  3. Nephrogenic systemic fibrosis (NSF) and gadolinium-based contrast ...

    African Journals Online (AJOL)

    Nephrogenic systemic fibrosis (NSF), unknown before March 1997 and first described in 2000, is a systemic disorder characterised by widespread tissue fibrosis. The first known case occurred in 1997, after the use of gadolinium-based contrast agents (GBCAs) at high doses in patients with renal failure had become routine.

  4. Formation of nanoclusters of gadolinium atoms in silicon

    International Nuclear Information System (INIS)

    Iliev, Kh.M.; Saparniyazova, Z.M.; Ismajlov, K.A.; Madzhitov, M.Kh.

    2011-01-01

    A technology of stage wise low temperature diffusion of gadolinium into silicon that makes it possible to form nanoclusters of impurity atoms with a significant magnetic moment distributed throughout the volume of the material has been developed. It is shown that, unlike the samples obtained by high temperature diffusion doping, the samples prepared by the new technology do not have surface erosion, and alloys and silicides are not formed in the near surface region. Nanoclusters of impurity atoms of gadolinium in the volume of the crystal lattice of the silicon are studied using an MIK-5 infrared microscope. It is found that, in the stage wise low temperature diffusion, the temperature and time of the diffusion have an effect not only on the depth of penetration of the impurities but also on the sizes of the resulting clusters; these factors can also prevent the formation of clusters. The study of the effect of low temperature treatments on the size and distribution of clusters shows that, upon annealing in the temperature range of 500-700 degrees Celsius, the ordering of the clusters of gadolinium impurity atoms is observed. A further increase in the annealing temperature leads to the destruction of gadolinium clusters in the silicon bulk. (authors)

  5. MR imaging of gestational trophoblastic tumor: role of gadolinium enhancement

    International Nuclear Information System (INIS)

    Choi, Si Young; Byun, Jae Young; Kim, Bum Su; Yun, Young Hyun; Mun, Kyung Mi; Park, Kyung Sin; Kim, Byung Kee; Bae, Seog Nyeon; Shinn, Kyung Sub.

    1997-01-01

    The purpose of this study is to investigate the role of gadolinium enhanced MR imaging in the evaluation of gestational trophoblastic tumors (invasive mole and choriocarcinoma). Pre-enhanced T1-and T2-weighted images and gadolinium enhanced T1-weighted images of 34 gestational trophoblastic tumors (15 choriocarcinomas, 19 invasive moles) were retrospectively evaluated and enhancement patterns were analyzed. Morphologica differences and structural characteristics were analyzed by the evaluation of tumor margin, patterns of hemorrhagic necroses, the development of intratumoral vascularity, and molar villi. Graded scores of MR findings between pre- and gadolinium enhanced images were based on the following criteria : 1) visualization of tumor margin 2) distinction between tumor necrosis and zone of trophoblastic proliferation ; and 3) molar villi. Statistical differences between graded scores of pre- and post-enhanced images were analyzed. Gadolinium enhanced MR imaging was helpful for the visualization of tumor characteristics in gestational trophoblastic tumors and in differential diagnosis between invasive mole and choriocarcinoma. (author). 16 refs., 4 tabs., 4 figs

  6. Early Gadolinium Enhancement for Determination of Area at Risk

    DEFF Research Database (Denmark)

    Hammer-Hansen, Sophia; Leung, Steve W; Hsu, Li-Yueh

    2017-01-01

    OBJECTIVES: The aim of this study was to determine whether early gadolinium enhancement (EGE) by cardiac magnetic resonance (CMR) in a canine model of reperfused myocardial infarction depicts the area at risk (AAR) as determined by microsphere blood flow analysis. BACKGROUND: It remains controver......OBJECTIVES: The aim of this study was to determine whether early gadolinium enhancement (EGE) by cardiac magnetic resonance (CMR) in a canine model of reperfused myocardial infarction depicts the area at risk (AAR) as determined by microsphere blood flow analysis. BACKGROUND: It remains...... requires pathological validation. METHODS: Eleven dogs underwent 2 h of coronary artery occlusion and 48 h of reperfusion before imaging at 1.5-T. EGE imaging was performed 3 min after contrast administration with coverage of the entire left ventricle. Late gadolinium enhancement imaging was performed...... on native T1 and T2 maps. The size of EGE was significantly greater than the infarct by triphenyltetrazolium chloride (44.1 ± 15.8% vs. 20.7 ± 14.4%; p gadolinium enhancement (44.1 ± 15.8% vs. 23.5 ± 12.7%; p

  7. Correlation between computer-aided dynamic gadolinium-enhanced MRI assessment of inflammation and semi-quantitative synovitis and bone marrow oedema scores of the wrist in patients with rheumatoid arthritis--a cohort study

    DEFF Research Database (Denmark)

    Boesen, Mikael; Kubassova, Olga; Bouert, Rasmus

    2012-01-01

    Objective. To test the correlation between assessment of inflammation using dynamic contrast-enhanced MRI (DCE-MRI) analysed by a novel computer-aided approach and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RA MRI Scoring (RAMRIS) system, in the wrist...... extended region of interest (ROI) placed around the wrist joint (semi-automated approach) and (iii) within a small ROI placed in the area with most visual enhancement (semi-automated approach). Time spent on each procedure was noted. Spearman's rank correlation test was applied to assess the correlation...... between RAMRIS and the computer-generated dynamic parameters. Results. RAMRIS synovitis (range 2-9), BME (range 0-39) and the dynamic parameters reflecting the number of enhancing voxels were significantly correlated, especially when an extended ROI around the wrist was used (¿¿=¿0.74; P¿...

  8. Magnetic resonance characteristics and susceptibility weighted imaging of the brain in gadolinium encephalopathy.

    Science.gov (United States)

    Samardzic, Dejan; Thamburaj, Krishnamoorthy

    2015-01-01

    To report the brain imaging features on magnetic resonance imaging (MRI) in inadvertent intrathecal gadolinium administration. A 67-year-old female with gadolinium encephalopathy from inadvertent high dose intrathecal gadolinium administration during an epidural steroid injection was studied with multisequence 3T MRI. T1-weighted imaging shows pseudo-T2 appearance with diffusion of gadolinium into the brain parenchyma, olivary bodies, and membranous labyrinth. Nulling of cerebrospinal fluid (CSF) signal is absent on fluid attenuation recovery (FLAIR). Susceptibility-weighted imaging (SWI) demonstrates features similar to subarachnoid hemorrhage. CT may demonstrate a pseudo-cerebral edema pattern given the high attenuation characteristics of gadolinium. Intrathecal gadolinium demonstrates characteristic imaging features on MRI of the brain and may mimic subarachnoid hemorrhage on susceptibility-weighted imaging. Identifying high dose gadolinium within the CSF spaces on MRI is essential to avoid diagnostic and therapeutic errors. Copyright © 2013 by the American Society of Neuroimaging.

  9. Modeling the effect of succimer (DMSA; dimercaptosuccinic acid) chelation therapy in patients poisoned by lead.

    Science.gov (United States)

    van Eijkeren, Jan C H; Olie, J Daniël N; Bradberry, Sally M; Vale, J Allister; de Vries, Irma; Clewell, Harvey J; Meulenbelt, Jan; Hunault, Claudine C

    2017-02-01

    Kinetic models could assist clinicians potentially in managing cases of lead poisoning. Several models exist that can simulate lead kinetics but none of them can predict the effect of chelation in lead poisoning. Our aim was to devise a model to predict the effect of succimer (dimercaptosuccinic acid; DMSA) chelation therapy on blood lead concentrations. We integrated a two-compartment kinetic succimer model into an existing PBPK lead model and produced a Chelation Lead Therapy (CLT) model. The accuracy of the model's predictions was assessed by simulating clinical observations in patients poisoned by lead and treated with succimer. The CLT model calculates blood lead concentrations as the sum of the background exposure and the acute or chronic lead poisoning. The latter was due either to ingestion of traditional remedies or occupational exposure to lead-polluted ambient air. The exposure duration was known. The blood lead concentrations predicted by the CLT model were compared to the measured blood lead concentrations. Pre-chelation blood lead concentrations ranged between 99 and 150 μg/dL. The model was able to simulate accurately the blood lead concentrations during and after succimer treatment. The pattern of urine lead excretion was successfully predicted in some patients, while poorly predicted in others. Our model is able to predict blood lead concentrations after succimer therapy, at least, in situations where the duration of lead exposure is known.

  10. Toxicity of copper chelates of azomethines and amino acids for Chlorella pyrenoidosa

    Energy Technology Data Exchange (ETDEWEB)

    Barashkov, G.K.; Rukhadze, E.G.; Talyzenkova, G.P.

    1979-01-01

    The authors have attempted to assess the toxicity of copper-containing compounds from the point of view of their interrelationship with the structural characteristics of the chelate compound and the structure of the ligand. The copper chelates of the azomethines tested may be provisionally divided into three types: A - complexes with N-alkly-azomethines; B - complexes with N-aryl-azomethines; C - binuclear complexes. Consideration was also given to chelates with aromatic and heterocyclic amino acids and to heteroligand chelates in which the copper atom coordinates azomethine and an amino acid simultaneously. Toxicity was determined by the method previously described and expressed as a critical concentration (C/sub cr/, mg Cu/liter) and in relative toxicity units (T/sub c/). The compounds investigated were obtained from the interaction between a bidentant ligand of an azomethine or anamino acid and copper acetate in a water-alcohol medium at pH 6-8. Since they are not very soluble in water, true solutions were obtained by using dimethyl sulfoxide.

  11. Fat-saturated post gadolinium T1 imaging of the brain in multiple sclerosis

    International Nuclear Information System (INIS)

    Al-Saeed, Osama; Sheikh, Mehraj; Ismail, Mohammed; Athyal, Reji

    2011-01-01

    Background Magnetic resonance imaging (MRI) is of vital importance in the diagnosis and follow-up of patients with multiple sclerosis (MS). Imaging sequences better demonstrating enhancing lesions can help in detecting active MS plaques. Purpose To evaluate the role of fat-saturated gadolinium-enhanced T1-weighted (T1W) images of the brain in MS and to assess the benefit of performing this additional sequence in the detection of enhancing lesions. Material and Methods In a prospective study over a six-month period, 70 consecutive patients with clinically diagnosed MS were enrolled. These constituted 14 male and 56 female patients between the ages of 21 and 44 years. All the patients underwent brain MRIs on a 1.5 Tesla Magnet. Gadolinium-enhanced T1 images with and without fat saturation were compared and results were recorded and analyzed using a conspicuity score and McNemar test. Results There were a total of 157 lesions detected in 70 patients on post-contrast T1W fat-saturated images compared with 139 lesions seen on the post-contrast T1W fast spin-echo (FSE) images. This was because 18 of the lesions (11.5%) were only seen on the fat-saturated images. In addition, 15 lesions were more conspicuous on the fat saturation sequence (9.5%). The total conspicuity score obtained, including all the lesions, was 2.24 +/-0.60 (SD). Using the two-tailed McNemar test for quantitative analysis, the P value obtained was <0.0001. Conclusion T1W fat-saturated gadolinium-enhanced images show better lesion enhancement than T1W images without fat saturation

  12. Chelate-assisted phytoextraction of lead from contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, E.M.; Sims, J.T.; Cunningham, S.D.; Huang, J.W.; Berti, W.R.

    1999-12-01

    Phytoextraction, a remediation strategy for lead (Pb)-contaminated soils that removes soil Pb through plant uptake and harvest, may be enhanced by use of synthetic chelates. The authors evaluated Pb desorption from four contaminated soils by seven chelates (CDTA, DTPA, EDDHA, EFTA, HEDTA, HEIDA, and NTA) at three rates. The three most effective chelates (CDTA, DTPA, and HEDTA) were used in greenhouse studies with an uncontaminated soil and a Pb-contaminated soil to determine the effect of chelate type and rate on growth, Pb uptake, and plant elemental composition. Lead desorption varied with chelate and soil and increased with chelate rate, averaging 948 mg Pb kg{sup {minus}1} at the 20 mmol kg{sup {minus}1} rate vs. 28 mg Pb kg{sup {minus}1} by the control. The general ranking of chelate effectiveness, based on total Pb desorbed, was HEDTA > CDTA > DTPA > EGTA > HEIDA > EDDHA {approximately} NTA. Plant uptake of Pb from the contaminated soil was enhanced by CDTA, DTPA, and HEDTA, but with even the most effective treatment (corn, high CDTA rate), the amount of Pb extracted by plants was rather low. Lead extractable by the Toxicity Characteristic Leaching Procedure (TCLP) was increased from 9 mg L{sup {minus}1} in the control to from 47 to 174 mg L{sup {minus}1} in soils treated with 20 mmol kg{sup {minus}1} CDTA or DTPA and chelates generally caused a shift in Pb from resistant to more soluble chemical fractions.

  13. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and

  14. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    Science.gov (United States)

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  15. Development of iron chelators for Cooley's anemia. Final report

    International Nuclear Information System (INIS)

    Crosby, W.H.; Green, R.

    1982-01-01

    Iron chelators were screened in an iron-loaded rat model using selective radioiron probes. In all experiments, chelators D and F, in that order, induced significant loss of radioiron compared with controls. However, use of chelator D was associated with side effects, and resulted in the death of some animals. There was some evidence that chelator A also caused iron loss significantly greater than controls. Chelators B, C and E were without apparent enhancing effect on radioiron excretion. This was a blind study and the compounds used were A - 2,3-Dihydroxybenzoic acid; B - N,N1-Dimethyladipohydroxamic acid; C - DL-Phenylalanine hydroxamic acid; D - Ethylenediamine-N,N1-bis(2-hydroxphenylacetic acid); E - Propionohydroxamic acid; and F - Deferrioxamine B

  16. Morphological imaging and T2 and T2* mapping of hip cartilage at 7 Tesla MRI under the influence of intravenous gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Lazik-Palm, Andrea; Geis, Christina; Goebel, Juliane; Theysohn, Jens M. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Kraff, Oliver; Johst, Soeren [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Ladd, Mark E. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); German Cancer Research Center (DKFZ), Division of Medical Physics in Radiology, Heidelberg (Germany); Quick, Harald H. [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High-Field and Hybrid MR Imaging, Essen (Germany)

    2016-11-15

    To investigate the influence of intravenous gadolinium on cartilage T2 and T2* relaxation times and on morphological image quality at 7-T hip MRI. Hips of 11 healthy volunteers were examined at 7 T. Multi-echo sequences for T2 and T2* mapping, 3D T1 volumetric interpolated breath-hold examination (VIBE) and double-echo steady-state (DESS) sequences were acquired before and after intravenous application of gadolinium according to a delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) protocol. Cartilage relaxation times were measured in both scans. Morphological sequences were assessed quantitatively using contrast ratios and qualitatively using a 4-point Likert scale. Student's t-test, Pearson's correlation (ρ) and Wilcoxon sign-rank test were used for statistical comparisons. Pre- and post-contrast T2 and T2* values were highly correlated (T2: acetabular: ρ = 0.76, femoral: ρ = 0.77; T2*: acetabular: ρ = 0.80, femoral: ρ = 0.72). Gadolinium enhanced contrasts between cartilage and joint fluid in DESS and T1 VIBE according to the qualitative (p = 0.01) and quantitative (p < 0.001) analysis. The delineation of acetabular and femoral cartilage and the labrum predominantly improved with gadolinium. Gadolinium showed no relevant influence on T2 or T2* relaxation times and improved morphological image quality at 7 T. Therefore, morphological and quantitative sequences including dGEMRIC can be conducted in a one-stop-shop examination. (orig.)

  17. 3D gadolinium-enhanced MRI venography: Evaluation of central chest veins and impact on patient management

    International Nuclear Information System (INIS)

    Oxtoby, J.W.; Widjaja, E.; Gibson, K.M.; Uzoka, K.

    2001-01-01

    AIM: To assess the value of a simplified 3D gadolinium-enhanced magnetic resonance imaging (MRI) venography for central chest veins. MATERIALS AND METHODS: In this retrospective study of 24 patients, the MRI findings and medical records were reviewed to determine whether MRI results correlated with subsequent findings, and to determine the effect on clinical management. 3D steady state gradient-echo sequence, fast imaging with steady state precession (FISP), was used. We employed a simplified protocol not requiring bolus timing or subtraction to achieve rapid data acquisition and hence good compliance in this group of frail patients. Following intravenous administration of a bolus of gadolinium, two acquisitions were obtained in order to ensure adequate opacification of all veins. Individual partitions and maximum intensity projections were then analysed to determine whether the veins were patent, stenosed or occluded. RESULTS: The indications for MRI were to assess the patency of central veins for the purpose of cannulation or arteriovenous fistula formation in 17 patients. Out of the 12 patients who proceeded to an intervention, MRI venography successfully predicted an appropriate site in 10 patients. In the remaining seven patients, MRI venography was valuable in confirming or excluding the clinical suspicion of central venous thrombosis and directly influenced the management in five patients. CONCLUSION: 3D gadolinium-enhanced MRI venography is a valuable means of providing a global representation of the central venous system and guiding subsequent central venous cannulation. Oxtoby, J.W. et al. (2001)

  18. Deep learning enables reduced gadolinium dose for contrast-enhanced brain MRI.

    Science.gov (United States)

    Gong, Enhao; Pauly, John M; Wintermark, Max; Zaharchuk, Greg

    2018-02-13

    There are concerns over gadolinium deposition from gadolinium-based contrast agents (GBCA) administration. To reduce gadolinium dose in contrast-enhanced brain MRI using a deep learning method. Retrospective, crossover. Sixty patients receiving clinically indicated contrast-enhanced brain MRI. 3D T 1 -weighted inversion-recovery prepped fast-spoiled-gradient-echo (IR-FSPGR) imaging was acquired at both 1.5T and 3T. In 60 brain MRI exams, the IR-FSPGR sequence was obtained under three conditions: precontrast, postcontrast images with 10% low-dose (0.01mmol/kg) and 100% full-dose (0.1 mmol/kg) of gadobenate dimeglumine. We trained a deep learning model using the first 10 cases (with mixed indications) to approximate full-dose images from the precontrast and low-dose images. Synthesized full-dose images were created using the trained model in two test sets: 20 patients with mixed indications and 30 patients with glioma. For both test sets, low-dose, true full-dose, and the synthesized full-dose postcontrast image sets were compared quantitatively using peak-signal-to-noise-ratios (PSNR) and structural-similarity-index (SSIM). For the test set comprised of 20 patients with mixed indications, two neuroradiologists scored blindly and independently for the three postcontrast image sets, evaluating image quality, motion-artifact suppression, and contrast enhancement compared with precontrast images. Results were assessed using paired t-tests and noninferiority tests. The proposed deep learning method yielded significant (n = 50, P 5 dB PSNR gains and >11.0% SSIM). Ratings on image quality (n = 20, P = 0.003) and contrast enhancement (n = 20, P deep learning method, gadolinium dose can be reduced 10-fold while preserving contrast information and avoiding significant image quality degradation. 3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

  19. Treating Lead Toxicity: Possibilities beyond Synthetic Chelation

    Directory of Open Access Journals (Sweden)

    Shambhavi Tannir

    2013-01-01

    Full Text Available Lead, a ubiquitous metal, is one of the most abundant elements present on earth. Its easy availability and cost effectiveness made it an extremely popular component in the industrial revolution. However, its hazardous health effects were not considered at the time. Over the last few decades, with the adverse effects of lead coming to the forefront, nations across the world have started to recognize and treat lead toxicity. The most reliable and used method until now has been chelation therapy. Recent research has suggested the use of natural products and sources to treat lead poisoning with minimal or no side effects. This review has tried to summarize a few of the natural products/sources being investigated by various groups.

  20. Left Ventricular Function Evaluation on a 3T MR Scanner with Parallel RF Transmission Technique: Prospective Comparison of Cine Sequences Acquired before and after Gadolinium Injection.

    Science.gov (United States)

    Caspar, Thibault; Schultz, Anthony; Schaeffer, Mickaël; Labani, Aïssam; Jeung, Mi-Young; Jurgens, Paul Thomas; El Ghannudi, Soraya; Roy, Catherine; Ohana, Mickaël

    To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function. 25 consecutive patients scheduled for a cardiac MRI were prospectively included and had their b-TFE cine sequences acquired before and right after gadobutrol injection. Images were assessed qualitatively (overall image quality, LV edge sharpness, artifacts and LV wall motion) and quantitatively with measurement of LVEF, LV mass, and telediastolic volume and contrast-to-noise ratio (CNR) between the myocardium and the cardiac chamber. Statistical analysis was conducted using a Bayesian paradigm. No difference was found before or after injection for the LVEF, LV mass and telediastolic volume evaluations. Overall image quality and CNR were significantly lower after injection (estimated coefficient cine after > cine before gadolinium: -1.75 CI = [-3.78;-0.0305], prob(coef>0) = 0% and -0.23 CI = [-0.49;0.04], prob(coef>0) = 4%) respectively), but this decrease did not affect the visual assessment of LV wall motion (cine after > cine before gadolinium: -1.46 CI = [-4.72;1.13], prob(coef>0) = 15%). In 3T cardiac MRI acquired with parallel RF transmission technique, qualitative and quantitative assessment of LV function can reliably be performed with cine sequences acquired after gadolinium injection, despite a significant decrease in the CNR and the overall image quality.

  1. f-Element Ion Chelation in Highly Basic Media - Final Report

    International Nuclear Information System (INIS)

    Paine, R.T.

    2000-01-01

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  2. In vitro uptake of 153gadolinium and gadolinium complexes by hyaline articular cartilage

    International Nuclear Information System (INIS)

    Engel, A.; Fleischmann, D.; Hamilton, G.; Hajek, P.

    1990-01-01

    This in vitro study evaluated whether Gadolinium (Gd) penetrates into hyaline cartilage and would be incorporated into vital chondrocytes. Hyaline joint cartilage of rabbits was exposed to radioactive 153 GdCl 3 and to a radioactive 153 Gd-DTPA-BSA-complex (DTPA, diethylene-triaminepentaacetic acid; BSA, bovine serum albumine). In addition an exchange experiment with radioactive 153 GdCl 3 versus Gd-DTPA-di-N-methylglucamine (Magnevist) was performed. Incorporation of 153 GdCl 3 into neuroblastoma cells, connective tissue cells and chondrocytes was tested. The results showed that the depth and extent of incorporation of Gd depends on the molecular mass and time of exposure. 153 Gd-DTPA-BSA complexes exhibited an incorporation rate of maximal 11 per cent ± 2.8 per cent up to the middle third of the cartilage within 24 h with almost no incorporation (2 ± 1.9 per cent) for the deep layer. The exchange experiment revealed no uptake of Gd for the deep layer. The maximal incorporation rate of 153 GdCl 3 into vital chondrocytes was 6.3 per cent. These data indicate that under the condition of MR-arthrography, Gd-DTPA-di-N-methylglucamine will not be absorbed into the deep layers of hyaline cartilage and will not be incorporated into vital chondrocytes. (author). 8 refs.; 3 tabs

  3. Chelation technology: a promising green approach for resource management and waste minimization.

    Science.gov (United States)

    Chauhan, Garima; Pant, K K; Nigam, K D P

    2015-01-01

    Green chemical engineering recognises the concept of developing innovative environmentally benign technologies to protect human health and ecosystems. In order to explore this concept for minimizing industrial waste and for reducing the environmental impact of hazardous chemicals, new greener approaches need to be adopted for the extraction of heavy metals from industrial waste. In this review, a range of conventional processes and new green approaches employed for metal extraction are discussed in brief. Chelation technology, a modern research trend, has shown its potential to develop sustainable technology for metal extraction from various metal-contaminated sites. However, the interaction mechanism of ligands with metals and the ecotoxicological risk associated with the increased bioavailability of heavy metals due to the formation of metal-chelant complexes is still not sufficiently explicated in the literature. Therefore, a need was felt to provide a comprehensive state-of-the-art review of all aspects associated with chelation technology to promote this process as a green chemical engineering approach. This article elucidates the mechanism and thermodynamics associated with metal-ligand complexation in order to have a better understanding of the metal extraction process. The effects of various process parameters on the formation and stability of complexes have been elaborately discussed with respect to optimizing the chelation efficiency. The non-biodegradable attribute of ligands is another important aspect which is currently of concern. Therefore, biotechnological approaches and computational tools have been assessed in this review to illustrate the possibility of ligand degradation, which will help the readers to look for new environmentally safe mobilizing agents. In addition, emerging trends and opportunities in the field of chelation technology have been summarized and the diverse applicability of chelation technology in metal extraction from

  4. Dual contrast enhanced magnetic resonance imaging of the liver with superparamagnetic iron oxide followed by gadolinium for lesion detection and characterization

    International Nuclear Information System (INIS)

    Kubaska, Samantha; Sahani, Dushyant V.; Saini, Sanjay; Hahn, Peter F.; Halpern, Elkan

    2001-01-01

    AIM: Iron oxide contrast agents are useful for lesion detection, and extracellular gadolinium chelates are advocated for lesion characterization. We undertook a study to determine if dual contrast enhanced liver imaging with sequential use of ferumoxides particles and gadolinium (Gd)-DTPA can be performed in the same imaging protocol. MATERIALS AND METHODS: Sixteen patients underwent dual contrast magnetic resonance imaging (MRI) of the liver for evaluation of known/suspected focal lesions which included, metastases (n = 5), hepatocellular carcinoma (HCC;n = 3), cholangiocharcinoma(n = 1) and focal nodular hyperplasia (FNH;n = 3). Pre- and post-iron oxide T1-weighted gradient recalled echo (GRE) and T2-weighted fast spin echo (FSE) sequences were obtained, followed by post-Gd-DTPA (0.1 mmol/kg) multi-phase dynamic T1-weighted out-of-phase GRE imaging. Images were analysed in a blinded fashion by three experts using a three-point scoring system for lesion conspicuity on pre- and post-iron oxide T1 images as well as for reader's confidence in characterizing liver lesions on post Gd-DTPA T1 images. RESULTS: No statistically significant difference in lesion conspicuity was observed on pre- and post-iron oxide T1-GRE images in this small study cohort. The presence of iron oxide did not appreciably diminish image quality of post-gadolinium sequences and did not prevent characterization of liver lesions. CONCLUSION: Our results suggest that characterization of focal liver lesion with Gd-enhanced liver MRI is still possible following iron oxide enhanced imaging. Kubaska, S. et al. (2001)

  5. Rapid microwave-assisted synthesis of PVP-coated ultrasmall gadolinium oxide nanoparticles for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Vahdatkhah, Parisa [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Madaah Hosseini, Hamid Reza, E-mail: Madaah@sharif.ir [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Khodaei, Azin [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Montazerabadi, Ali Reza [Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (Iran, Islamic Republic of); Irajirad, Rasoul [Biomolecular Image Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (Iran, Islamic Republic of); Oghabian, Mohamad Ali [Biomolecular Image Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (Iran, Islamic Republic of); Delavari, Hamid H., E-mail: Hamid.delavari@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, Tehran, PO Box 14115-143 (Iran, Islamic Republic of)

    2015-05-12

    Highlights: • A rapid microwave-assisted polyol process used to synthesize Gd{sub 2}O{sub 3} nanoparticles. • In situ surface modification of ultrasmall Gd{sub 2}O{sub 3}NPs with PVP has been performed. • Gd{sub 2}O{sub 3}NPs shows considerable increasing of relaxivity in comparison to Gd-chelates. • PVP-covered Gd{sub 2}O{sub 3}NPs show appropriate stability for approximately 15 days. • Spectrophotometric indicates the leaching of free Gd ions not occurred versus time. - Abstract: Synthesis of polyvinyl pyrrolidone (PVP) coated ultrasmall Gd{sub 2}O{sub 3} nanoparticles (NPs) with enhanced T{sub 1}-weighted signal intensity and r{sub 2}/r{sub 1} ratio close to unity is performed by a microwave-assisted polyol process. PVP coated Gd{sub 2}O{sub 3}NPs with spherical shape and uniform size of 2.5 ± 0.5 nm have been synthesized below 5 min and structure and morphology confirmed by HRTEM, XRD and FTIR. The longitudinal (r{sub 1}) and transversal relaxation (r{sub 2}) of Gd{sub 2}O{sub 3}NPs is measured by a 3 T MRI scanner. The results showed considerable increasing of relaxivity for Gd{sub 2}O{sub 3}NPs in comparison to gadolinium chelates which are commonly used for clinical magnetic resonance imaging. In addition, a mechanism for Gd{sub 2}O{sub 3}NPs formation and in situ surface modification of PVP-grafted Gd{sub 2}O{sub 3}NPs is proposed.

  6. Differentiation of recurrent breast cancer from radiation fibrosis with dynamic gadolinium-enhanced MR imaging

    International Nuclear Information System (INIS)

    Dao, T.H.; Campana, F.; Fourquet, A.; Rahmouni, A.

    1991-01-01

    This paper assesses the ability of dynamic gadolinium-enhanced MR imaging to differentiate radiation fibrosis from tumor recurrence of breast cancer after conservative treatment. Twenty-five women with previous breast cancer treated with radiation therapy underwent MR imaging examination. Tumor recurrence was suspected on palpation of masses (18 cases) or at mammography (7 cases). The MR imaging protocol was performed on a 0.5-T imager with a breast coil and included T1 and T2 spin-echo, short To inversion recovery (STIR), and dynamic gadolinium-enhanced T1-weighted sequenced to evaluate the hemokinetics of the lesion. Ratios of signal intensity of suspected lesions to that of fat, surrounding breast gland, and background noise were calculated. Percutaneous biopsies were performed in all cases after MR imaging. Curves of signal-to-noise ratio of recurrences (5 cases) showed an early enhancement within the first minutes after injection, although localized fibrosis (20 cases) was not significantly enhanced. T2 and STIR sequences were not contributive in differentiating fibrosis from tumor recurrence

  7. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    Directory of Open Access Journals (Sweden)

    Margaret E. Sears

    2013-01-01

    Full Text Available Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

  8. Homogeneous dispersion of gadolinium oxide nanoparticles into a non-aqueous-based polymer by two surface treatments

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, Jorice, E-mail: jorice.samuel@gmail.com [AREVA T and D UK Ltd, AREVA T and D Research and Technology Centre (United Kingdom); Raccurt, Olivier [NanoChemistry and Nanosafety Laboratory (DRT/LITEN/DTNM/LCSN), CEA Grenoble, Department of NanoMaterials (France); Mancini, Cedric; Dujardin, Christophe; Amans, David; Ledoux, Gilles [Universite de Lyon, Laboratoire de Physico Chimie des Materiaux Luminescents (LPCML) (France); Poncelet, Olivier [NanoChemistry and Nanosafety Laboratory (DRT/LITEN/DTNM/LCSN), CEA Grenoble, Department of NanoMaterials (France); Tillement, Olivier [Universite de Lyon, Laboratoire de Physico Chimie des Materiaux Luminescents (LPCML) (France)

    2011-06-15

    Gadolinium oxide nanoparticles are more and more used. They can notably provide interesting fluorescence properties. Herein they are incorporated into a non-aqueous-based polymer, the poly(methyl methacrylate). Their dispersion within the polymer matrix is the key to improve the composite properties. As-received gadolinium oxide nanopowders cannot be homogeneously dispersed in such a polymer matrix. Two surface treatments are, therefore, detailed and compared to achieve a good stability of the nanoparticles in a non-aqueous solvent such as the 2-butanone. Then, once the liquid suspensions have been stabilized, they are used to prepare nanocomposites with homogeneous particles dispersion. The two approaches proposed are an hybrid approach based on the growth of a silica shell around the gadolinium oxide nanoparticles, and followed by a suitable silane functionalization; and a non-hybrid approach based on the use of surfactants. The surface treatments and formulations involved in both methods are detailed, adjusted and compared. Thanks to optical methods and in particular to the use of a 'home made' confocal microscope, the dispersion homogeneity within the polymer can be assessed. Both methods provide promising and conclusive results.

  9. Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury.

    Science.gov (United States)

    Gulati, Puja; Muthuraman, Arunachalam; Jaggi, Amteshwar S; Singh, Nirmal

    2013-03-01

    The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.

  10. A first principles kinetic Monte Carlo investigation of the adsorption and mobility of gadolinium on the (100) surface of tungsten

    International Nuclear Information System (INIS)

    Samin, Adib J.; Zhang, Jinsuo

    2017-01-01

    An accurate characterization of lanthanide adsorption and mobility on tungsten surfaces is important for pyroprocessing. In the present study, the adsorption and diffusion of gadolinium on the (100) surface of tungsten was investigated. It was found that the hollow sites were the most energetically favorable for the adsorption. It was further observed that a magnetic moment was induced following the adsorption of gadolinium on the tungsten surface and that the system with adsorbed hollow sites had the largest magnetization. A pathway for the surface diffusion of gadolinium was determined to occur by hopping between the nearest neighbor hollow sites via the bridge site and the activation energy for the hop was calculated to be 0.75 eV. The surface diffusion process was further assessed using two distinct kinetic Monte Carlo models; one that accounted for lateral adsorbate interactions up to the second nearest neighbor and one that did not account for such interatomic interactions in the adlayer. When the lateral interactions were included in the simulations, the diffusivity was observed to have a strong dependence on coverage (for the coverage values being studied). The effects of lateral interactions were further observed in a one-dimensional simulation of the diffusion equation where the asymmetry in the surface coverage profile upon its approach to a steady state distribution was clear in comparison with the simulations which did not account for those interactions.

  11. A first principles kinetic Monte Carlo investigation of the adsorption and mobility of gadolinium on the (100) surface of tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Samin, Adib J., E-mail: samin.2@osu.edu; Zhang, Jinsuo

    2017-05-15

    An accurate characterization of lanthanide adsorption and mobility on tungsten surfaces is important for pyroprocessing. In the present study, the adsorption and diffusion of gadolinium on the (100) surface of tungsten was investigated. It was found that the hollow sites were the most energetically favorable for the adsorption. It was further observed that a magnetic moment was induced following the adsorption of gadolinium on the tungsten surface and that the system with adsorbed hollow sites had the largest magnetization. A pathway for the surface diffusion of gadolinium was determined to occur by hopping between the nearest neighbor hollow sites via the bridge site and the activation energy for the hop was calculated to be 0.75 eV. The surface diffusion process was further assessed using two distinct kinetic Monte Carlo models; one that accounted for lateral adsorbate interactions up to the second nearest neighbor and one that did not account for such interatomic interactions in the adlayer. When the lateral interactions were included in the simulations, the diffusivity was observed to have a strong dependence on coverage (for the coverage values being studied). The effects of lateral interactions were further observed in a one-dimensional simulation of the diffusion equation where the asymmetry in the surface coverage profile upon its approach to a steady state distribution was clear in comparison with the simulations which did not account for those interactions.

  12. Gadolinium as a CT contrast agent: an experimental study for the effects of injection parameters in the rabbit brain model

    International Nuclear Information System (INIS)

    Kim, Hyun Jin; Choi, Hye Young; Lee, Sun Wha; Hwang, Ji Young

    2005-01-01

    We wanted to investigate the use of gadolinium based contrast agent (Gd-DTPA) for computed tomography (CT), and we also wanted to assess the effects of valuable injection parameters on enhancement in an experimental rabbit brain model. In vitro, attenuation measurements of serial dilutions of Gd-DTPA and iopromide were compared. In five rabbits, single level dynamic gadolinium-enhanced brain CT studies were obtained using different injection parameters. A comparision CT scan after iopromide administration was performed. The time-attenuation curves of the brain vessel and parenchyma were obtained and the magnitude of enhancement (Hmax) and the time to peak enhancement (Tmax) were analyzed. In vitro, the attenuation coefficient of undiluted Gd-DTPA (2,578 HU) was higher than that of iopromide (1,761 HU) at equimolar concentrations. In 5 rabbits, the time-attenuation curve demonstrated a distinct pattern with peak enhancement only in the brain vessel, but not in the brain parenchyma. There was increasing linear relationship between the injection rate of Gd-DTPA and Hmax, and a declining linear relationship with Tmax. The higher the concentration of Gd-DTPA, the higher Hmax was, but no significant difference was found for the Tmax. Higher volumes of Gd-DTPA revealed a higher Hmax and a delayed Tmax. Enhancement of the brain parenchyma on gadolinium-enhanced CT is minimal, while enhancement of the brain vessels is distinctive. The most important factor affecting Hmax of the vessel is the concentration of the contrast medium and the most important factor affecting Tmax of the vessel is volume of the contrast medium. The gadolinium-based contrast agent may be an reasonable alternative contrast agent for brain CT, and especially in cerebral vessels, and it may also be advantageous for brain parenchyma of those patients with BBB dysfunction

  13. Laser spectroscopy and laser isotope separation of atomic gadolinium

    International Nuclear Information System (INIS)

    Chen, Y. W.; Yamanaka, C.; Nomaru, K.; Kou, K.; Niki, H.; Izawa, Y.; Nakai, S.

    1994-01-01

    Atomic vapor laser isotope separation (AVLIS) is a process which uses intense pulsed lasers to selectively photoionize one isotopic species of a chemical element, after which these ions are extracted electromagnetically. The AVLIS has several advantages over the traditional methods based on the mass difference, such as high selectivity, low energy consumption, short starting time and versatility to any atoms. The efforts for atomic vapor laser isotope separation at ILT and ILE, Osaka University have been concentrated into the following items: 1) studies on laser spectroscopy and laser isotope separation of atomic gadolinium, 2) studies on interaction processes including coherent dynamics, propagation effects and atom-ion collision in AVLIS system, 3) development of laser systems for AVLIS. In this paper, we present experimental results on the laser spectroscopy and laser isotope separation of atomic gadolinium.

  14. Selectivity in extraction of copper and indium with chelate extractants

    International Nuclear Information System (INIS)

    Zivkovic, D.

    2003-01-01

    Simultaneous extraction of copper and indium with chelate extractants (LIX84 and D2E11PA) was described. Stechiometry of metal-organic complexes examined using the method of equimolar ratios resulted in CuR 2 and InR 3 forms of hydrophobic extracting species. A linear correlation was obtained between logarithm of distribution coefficients and chelate agents and pH, respectively. Selectivity is generally higher with higher concentrations of chelate agents in the organic phase, and is decreased with increase of concentration of hydrogen ions in feeding phase. (Original)

  15. Mixed and chelated waste test programs with bitumen solidification

    International Nuclear Information System (INIS)

    Simpson, S.I.; Morris, M.; Vidal, H.

    1988-01-01

    This paper presents the results of bitumen solidification tests on mixed wastes and chelated wastes. The French Atomic Energy Commission (CEA) performed demonstration tests on radioactive wastes contaminated with chelating agents for Associated Technologies, Inc. (ATI). The chelated wastes were produced and concentrated by Commonwealth Edison Co. as a result of reactor decontamination at Dresden Nuclear Station, Unit 1. Law Engineering in Charlotte, N. C. produced samples and performed tests on simulated heavy metal laden radioactive waste (mixed) to demonstrate the quality of the bituminous product. The simulation is intended to represent waste produced at Oak Ridge National Labs operated by Martin-Marietta

  16. Microwave and optical diagnostics in a gadolinium plasma

    International Nuclear Information System (INIS)

    Larousse, B.

    1997-01-01

    The optimization of the separation process of the gadolinium isotopes by Ion Cyclotron Resonance requires a precise knowledge of the physical characteristics of the plasma. Thus, two kinds of diagnostics have been developed: the first one to estimate the microwave power inside the source and the second one to measure the density of atomic and ionic of the gadolinium inside the plasma source and in front of the collector. Microwave diagnostic: A microstrip antenna has been designed and developed in order to characterize the microwave at 36 GHz frequency in the plasma source. The experimental results for different plasma regimes are presented. The measurements inside the plasma source show a maximum of microwave absorption for an argon pressure of 10 -4 mb (93% of absorption of the incident wave in the conditions of isotope separation). Laser absorption diagnostic: The theory of laser absorption in presence of a magnetic field is recalled and the first results are presented. In the spectral range between 560 and 620 nm, corresponding to high energy levels of gadolinium, no signal is obtained so that the density is below the detection limit 10 10 cm -3 . In the spectral range between 380 and 400 nm, two lines are observed, issue from the fundamental and metastable (633 cm -1 ) levels. The density of metastable level of gadolinium ions is about 10 10 cm -3 with a relative precision of 15 % and its variation is studied as a function of argon pressure, at different sections of the plasma column (source, collector). The achieved set of measurements has been performed in order to check the theoretical models. (author)

  17. Gadolinium burnable absorber optimization by the method of conjugate gradients

    International Nuclear Information System (INIS)

    Drumm, C.R.; Lee, J.C.

    1987-01-01

    The optimal axial distribution of gadolinium burnable poison in a pressurized water reactor is determined to yield an improved power distribution. The optimization scheme is based on Pontryagin's maximum principle, with the objective function accounting for a target power distribution. The conjugate gradients optimization method is used to solve the resulting Euler-Lagrange equations iteratively, efficiently handling the high degree of nonlinearity of the problem

  18. Laser ablation of Bi-substituted gadolinium iron garnet films

    International Nuclear Information System (INIS)

    Watanabe, N.; Hayashida, K.; Kawano, K.; Higuchi, K.; Ohkoshi, M.; Tsushima, K.

    1995-01-01

    Bi-substituted gadolinium iron garnet films were deposited by laser ablation. The composition, the structure and the magnetic properties of the films were found to be strongly dependent both on the compositions of the targets and on the pressure of oxygen. The highest values of Bi-substitution up to x=1.44 with uniform composition were obtained, after annealing in air. ((orig.))

  19. Growth and scintillation properties of gadolinium and yttrium orthovanadate crystals

    International Nuclear Information System (INIS)

    Voloshina, O.V.; Baumer, V.N.; Bondar, V.G.; Kurtsev, D.A.; Gorbacheva, T.E.; Zenya, I.M.; Zhukov, A.V.; Sidletskiy, O.Ts.

    2012-01-01

    Aiming to explore the possibility of using the undoped rare-earth orthovanadates as scintillation materials, we developed the procedure for growth of gadolinium (GdVO 4 ) and yttrium (YVO 4 ) orthovanadate single crystals by Czochralski method, and determined the optimal conditions of their after-growth annealing. Optical, luminescent, and scintillation properties of YVO 4 and GdVO 4 were discussed versus known literature data. Scintillation characteristics of GdVO 4 were determined for the first time.

  20. Synthesis and evaluation of gadolinium complexes based on PAMAM as MRI contrast agents.

    Science.gov (United States)

    Yan, Guo-Ping; Hu, Bin; Liu, Mai-Li; Li, Li-Yun

    2005-03-01

    Diethylenetriaminepentaacetic acid (DTPA) and pyridoxamine (PM) were incorporated into the amine groups on the surface of ammonia-core poly(amidoamine) dendrimers (PAMAM, Generation 2.0-5.0) to obtain dendritic ligands. These dendritic ligands were reacted with gadolinium chloride to yield the corresponding dendritic gadolinium (Gd) complexes. The dendritic ligands and their gadolinium complexes were characterized by(1)HNMR, IR, UV and elemental analysis. Relaxivity studies showed that the dendritic gadolinium complexes possessed higher relaxation effectiveness compared with the clinically used Gd-DTPA. After administration of the dendritic gadolinium complexes (0.09 mmol kg(-1) ) to rats, magnetic resonance imaging of the liver indicated that the dendritic gadolinium complexes containing pyridoxamine groups enhanced the contrast of the MR images of the liver, provided prolonged intravascular duration and produced highly contrasted visualization of blood vessels.

  1. Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy

    International Nuclear Information System (INIS)

    Lee, Dongkyu; Maeng, Inhee; Son, Joo-Hiuk; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol

    2009-01-01

    The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd 2 O 3 ) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

  2. Demonstration of pulmonary embolism with gadolinium-enhanced spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Coche, E.E.; Hammer, F.D.; Goffette, P.P. [Dept. of Radiology, St. Luc University Hospital, Brussels (Belgium)

    2001-11-01

    The authors report a case of successful detection of pulmonary embolism using gadolinium-enhanced spiral CT (Gadodiamide, 0.4 mmol/kg, 2 ml/s, delay 18 s) in a 77-year-old woman, with previous allergy to iodinated contrast medium, and renal failure, who presented with pulmonary arterial hypertension. Doppler ultrasound of the lower limbs was first performed and revealed a deep venous thrombosis of the right lower limb. To establish if venous thrombosis was the cause of pulmonary hypertension and to confirm that pulmonary endarterectomy was not indicated in this situation, several imaging modalities were performed. Lung scintigraphy and MRI were non-diagnostic. Gadolinium-enhanced spiral CT demonstrated a large thrombus located proximally and in a segmental artery of the right lower lobe. This case illustrates the potential usefulness of gadolinium as alternative contrast agent with spiral CT to diagnose pulmonary embolism and elucidate the cause of pulmonary arterial hypertension in a patient with some contraindications for iodinated contrast medium injection. (orig.)

  3. Demonstration of pulmonary embolism with gadolinium-enhanced spiral CT

    International Nuclear Information System (INIS)

    Coche, E.E.; Hammer, F.D.; Goffette, P.P.

    2001-01-01

    The authors report a case of successful detection of pulmonary embolism using gadolinium-enhanced spiral CT (Gadodiamide, 0.4 mmol/kg, 2 ml/s, delay 18 s) in a 77-year-old woman, with previous allergy to iodinated contrast medium, and renal failure, who presented with pulmonary arterial hypertension. Doppler ultrasound of the lower limbs was first performed and revealed a deep venous thrombosis of the right lower limb. To establish if venous thrombosis was the cause of pulmonary hypertension and to confirm that pulmonary endarterectomy was not indicated in this situation, several imaging modalities were performed. Lung scintigraphy and MRI were non-diagnostic. Gadolinium-enhanced spiral CT demonstrated a large thrombus located proximally and in a segmental artery of the right lower lobe. This case illustrates the potential usefulness of gadolinium as alternative contrast agent with spiral CT to diagnose pulmonary embolism and elucidate the cause of pulmonary arterial hypertension in a patient with some contraindications for iodinated contrast medium injection. (orig.)

  4. Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy (abstract)

    Science.gov (United States)

    Lee, Dongkyu; Maeng, Inhee; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol; Son, Joo-Hiuk

    2009-04-01

    The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd2O3) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

  5. Giant cisterna chyli: MRI depiction with gadolinium-DTPA enhancement

    International Nuclear Information System (INIS)

    Lee, K.C.Y.; Cassar-Pullicino, V.N.

    2000-01-01

    AIM: To demonstrate the use of MRI with Gadolinium-DTPA enhancement in the diagnosis of giant cisterna chyli. MATERIALS AND METHODS: The study consisted of contrast enhanced MRI with ultrasound and CT correlation in three patients with a giant cisterna chyli. An analysis of the morphology, location and post-contrast MR signal characteristics in relation to time was performed. RESULTS: Cisterna chyli has a characteristic lobulated morphology and location but the unenhanced MRI appearances are not specific. The post-Gadolinium-DTPA MRI appearances are critically dependent on the time elapsed after injection of contrast medium. Within the first 5 min, there is no enhancement at all, but by 10 min there is early layering of contrast medium evident, which by 30 min produces a clear fluid-fluid level. Delayed images at 4-5 h demonstrate a uniform enhancement of the cisternal contents producing a homogeneous intermediate signal. All of these features are best visualized on T1 fast saturation sequences. CONCLUSION: MRI with Gadolinium-DTPA enhancement is valuable in confirming the nature of the lymphatic ducts in the retroperitoneal space and helps to differentiate these normal structures from alternative lesions such as lymphadenopathy and tumour recurrence. Lee, K.C.Y., Cassar-Pullicino, V.N. (2000)

  6. Magnon contribution to electrical resistance of gadolinium-dysprosium alloy single crystals

    International Nuclear Information System (INIS)

    Nikitin, S.A.; Slobodchikov, S.S.; Solomkin, I.K.

    1978-01-01

    The magnon, phonon and interelectron collision contributions to the electric resistance of single crystals of gadolinium-dysprosium alloys were quantified. A relationship was found to exist between the electric resistance and the variation of the topology of the Fermi surface on melting of gadolinium with dysprosium. It was found that gadolinium-dysprosium alloys, which have no helicoidal magnetic structure in magnetically ordered state, feature a spin-spin helicoidal-type correlations in the paramagnetic field

  7. Comparison between gadolinium-enhanced 2D T1-weighted gradient-echo and spin-echo sequences in the detection of active multiple sclerosis lesions on 3.0T MRI

    Energy Technology Data Exchange (ETDEWEB)

    Aymerich, F.X. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, MR Unit. Department of Radiology (IDI), Barcelona (Spain); Universitat Politecnica de Catalunya - Barcelona Tech (UPC), Department of Automatic Control (ESAII), Barcelona (Spain); Auger, C.; Alcaide-Leon, P.; Pareto, D.; Huerga, E.; Corral, J.F.; Mitjana, R.; Rovira, A. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, MR Unit. Department of Radiology (IDI), Barcelona (Spain); Sastre-Garriga, J.; Montalban, X. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, Centre d' Esclerosi Multiple de Catalunya (Cemcat), Department of Neurology/Neuroimmunology, Barcelona (Spain)

    2017-04-15

    To compare the sensitivity of enhancing multiple sclerosis (MS) lesions in gadolinium-enhanced 2D T1-weighted gradient-echo (GRE) and spin-echo (SE) sequences, and to assess the influence of visual conspicuity and laterality on detection of these lesions. One hundred MS patients underwent 3.0T brain MRI including gadolinium-enhanced 2D T1-weighted GRE and SE sequences. The two sets of contrast-enhanced scans were evaluated in random fashion by three experienced readers. Lesion conspicuity was assessed by the image contrast ratio (CR) and contrast-to-noise ratio (CNR). The intracranial region was divided into four quadrants and the impact of lesion location on detection was assessed in each slice. Six hundred and seven gadolinium-enhancing MS lesions were identified. GRE images were more sensitive for lesion detection (0.828) than SE images (0.767). Lesions showed a higher CR in SE than in GRE images, whereas the CNR was higher in GRE than SE. Most misclassifications occurred in the right posterior quadrant. The gadolinium-enhanced 2D T1-weighted GRE sequence at 3.0T MRI enables detection of enhancing MS lesions with higher sensitivity and better lesion conspicuity than 2D T1-weighted SE. Hence, we propose the use of gadolinium-enhanced GRE sequences rather than SE sequences for routine scanning of MS patients at 3.0T. (orig.)

  8. Microwave and optical diagnostics in a gadolinium plasma; Diagnostics hyperfrequence et optique dans un plasma magnetise de gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Larousse, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    1997-12-31

    The optimization of the separation process of the gadolinium isotopes by Ion Cyclotron Resonance requires a precise knowledge of the physical characteristics of the plasma. Thus, two kinds of diagnostics have been developed: the first one to estimate the microwave power inside the source and the second one to measure the density of atomic and ionic of the gadolinium inside the plasma source and in front of the collector. Microwave diagnostic: A microstrip antenna has been designed and developed in order to characterize the microwave at 36 GHz frequency in the plasma source. The experimental results for different plasma regimes are presented. The measurements inside the plasma source show a maximum of microwave absorption for an argon pressure of 10{sup -4} mb (93% of absorption of the incident wave in the conditions of isotope separation). Laser absorption diagnostic: The theory of laser absorption in presence of a magnetic field is recalled and the first results are presented. In the spectral range between 560 and 620 nm, corresponding to high energy levels of gadolinium, no signal is obtained so that the density is below the detection limit 10{sup 10} cm{sup -3}. In the spectral range between 380 and 400 nm, two lines are observed, issue from the fundamental and metastable (633 cm{sup -1}) levels. The density of metastable level of gadolinium ions is about 10{sup 10} cm{sup -3} with a relative precision of 15 % and its variation is studied as a function of argon pressure, at different sections of the plasma column (source, collector). The achieved set of measurements has been performed in order to check the theoretical models. (author) 32 refs.

  9. 3-hydroxy-2(1H)-pyridinone chelating agents

    Science.gov (United States)

    Raymond, K.; Xu, J.

    1999-04-06

    Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

  10. Chelation of di- and trivalent iron with some polyaminopolycarboxylic acids

    International Nuclear Information System (INIS)

    Hafez, M.B.; Sharabi, Nahid; Patti, Francois.

    1979-02-01

    The chelation of di- and trivalent iron with some polyaminopolycarboxylic acids was studied. The influence of pH on the formation of the complex was investigated, the molecular ratio and the stability constants were determined [fr

  11. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  12. Gadolinium-enhanced turbo FLASH MR imaging of renal perfusion and excretion

    International Nuclear Information System (INIS)

    Watanabe, A.; Teresi, L.M.; Herbst, M.; O'Sullivan, R.M.; Lee, R.; Smith, C.; Renner, J.; Rappaport, A.; Bradley, W.G. Jr.

    1990-01-01

    This paper describes a novel approach to MR imaging of renal perfusion and excretion using gadolinium-enhanced, T1-weighted TURBP, fast low-angle shot (FLASH) imaging. Five normal volunteers and four patients were studied on a 1.5-T imaging system. Time-intensity curves of the appearance of gadolinium in each kidney and the bladder were then generated. In normal volunteers, marked first-pass enhancement of renal cortex followed by renal pyramids and collecting systems could be demonstrated on the first-pass gadolinium images. Delayed images showed hyperintense gadolinium within the bladder

  13. Heavy Metals, Cardiovascular Disease, and the Unexpected Benefits of Edetate Disodium Chelation Therapy

    Science.gov (United States)

    Lamas, Gervasio A.; Navas-Acien, Ana; Mark, Daniel B.; Lee, Kerry L.

    2016-01-01

    This review summarizes evidence from 2 lines of research previously thought unrelated: the unexpectedly positive results of the Trial to Assess Chelation Therapy (TACT), and a body of epidemiological data showing that accumulation of biologically active metals, such as lead and cadmium, is an important risk factor for cardiovascular disease. Considering these 2 areas of work together may lead to the identification of new, modifiable risk factors for atherosclerotic cardiovascular disease. We examine the history of chelation up through the report of TACT. We then describe work connecting higher metal levels in the body with the future risk of cardiovascular disease. We conclude by presenting a brief overview of a newly planned National Institutes of Health trial, TACT2, in which we will attempt to replicate the findings of TACT and to establish that removal of toxic metal stores from the body is a plausible mechanistic explanation for the benefits of edetate disodium treatment. PMID:27199065

  14. Environmental behaviour und ecotoxiology of gadolinium-containing MRT contrast media; Umweltverhalten und Oekotoxikologie von gadoliniumhaltigen Magnetresonanztomographie-Kontrastmitteln

    Energy Technology Data Exchange (ETDEWEB)

    Neubert, Claudia

    2008-07-08

    Magnetic resonance imaging (MRI) is an essential tool in noninvasive diagnostics. In order to improve the sensitivity and specificity of diagnoses, several contrast enhancing agents have been developed in the last few decades by various pharmaceutical manufacturers. Gadolinium (Gd), a lanthanide, is the most widely used metal in MRI contrast agents. Its ion has paramagnetic properties (seven unpaired electrons) and a very long electronic relaxation time. Due to the toxicity of free Gd, clinical use is only possible in a complexed form. Commonly used chelating agents are polyamino-polycarboxylic ligands such as DTPA. Due to the exceptional stability of these highly hydrophilic chelates and the lack of human metabolism, the contrast media are quantitatively excreted unchanged after the administration, and are subsequently emitted into the aquatic environment. Several studies have shown notable increases in Gd concentrations in surface or groundwaters receiving sewage effluents, an observation which has been termed ''Gd anomaly''. The Gd anomaly results from the use of MRI contrast agents for which the most significant entry route is the effluent from wastewater treatment works. Relatively little information on the aquatic toxicity of Gd or Gd-chelates has been published up to 2006. Therefore, in a first step, the acute aquatic toxicity of several MRI contrast agents was investigated in fish, daphnia and algae at high concentrations. Furthermore, chronic toxicity tests on fish and daphnia were conducted. The results showed that contrast enhancing agents containing Gd have no toxic effects on the tested organisms at concentrations being of relevance to the environment. At high concentrations growth inhibition of green algae was observed. The environmental fate and the biological degradation of the contrast media was studied in a model wastewater treatment plant and in aquatic sediment systems. The test compounds were neither biodegradable in the

  15. Detection of brain metastasis. Comparison of Turbo-FLAIR imaging, T2-weighted imaging and double-dose gadolinium-enhanced MR imaging

    International Nuclear Information System (INIS)

    Okubo, Toshiyuki; Hayashi, Naoto; Shirouzu, Ichiro; Abe, Osamu; Ohtomo, Kuni; Sasaki, Yasuhito; Aoki, Shigeki; Wada, Akihiko

    1998-01-01

    The purpose of this study was to compare Turbo-FLAIR imaging, T 2 -weighted imaging, and double-dose gadolinium-enhanced MR imaging in the detection of brain metastasis. Using the three sequences, 20 consecutive patients with brain metastases were prospectively studied with a 1.5-Tesla system. Three independent, blinded readers assessed the images for the presence, size, number, and location of metastatic lesions. In the detection of large lesions (>0.5 cm), Turbo-FLAIR imaging (38/48, 79%) was not significantly different from gadolinium-enhanced imaging (42/48, 88%) (p=0.273). T 2 -weighted imaging (31/48, 65%), however, was inferior to gadolinium-enhanced imaging (p<0.05). There was no difference between Turbo-FLAIR imaging and gadolinium-enhanced imaging in the accuracy of detecting solitary brain metastasis (4/4, 100%). In conclusion, Turbo-FLAIR imaging is a useful, noninvasive screening modality for brain metastasis. Its use may lead to cost savings in the diagnosis of brain metastases and may impact positively the cost-effectiveness of treatment. (author)

  16. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    International Nuclear Information System (INIS)

    Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

    2007-01-01

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics

  17. Effect of Ionic and Chelate Assisted Hexavalent Chromium on Mung Bean Seedlings (Vigna radiata L. wilczek. var k-851 During Seedling Growth

    Directory of Open Access Journals (Sweden)

    Mohanty, Monalisa

    2013-04-01

    Full Text Available The effect of Cr+6 with and without chelating agents were assessed in mung bean seedlings grown hydroponically. It was noted that the growth parameters showed a declining trend with increasing Cr+6 concentrations without chelate application. Among the seedlings grown with chelated chromium complexes, Cr+6–DTPA (10µM showed highest growth rate of roots as well as shoots. At higher concentration of Chromium i.e. Cr+6 (100µM, there exhibited high chlorophyll content in mung bean leaves where the seedlings showed stunted growth. The seedlings treated without and with chelated chromium complexes showed increased proline content as compared to control. The enzymatic study showed that, the catalase activity was maximum in shoots as compared to roots and the reverse is true in the case of peroxidase activity i.e. the roots showed higher value than that of the shoots.

  18. Patterns of disease on MRI in 53 children with tuberculous spondylitis and the role of gadolinium

    International Nuclear Information System (INIS)

    Andronikou, Savvas; Jadwat, Saaleha; Douis, Hassan

    2002-01-01

    Tuberculosis (TB) of the spine is the most common site of osseous involvement and has a higher prevalence in developing nations with an increasing incidence in developed nations. There are few paediatric reports of TB spondylitis (TBS) that include MRI findings.Objective. To determine the MRI characteristics of TBS in children with special reference to gadolinium enhancement and findings on follow-up MRI.Materials and methods. A retrospective review of patient records and MRI scans by three readers using a consensus method of 53 patients below 13 years of age.Results. Seventy-nine percent presented with kyphosis. MRI showed thoracic involvement in 83%. Eighty-five percent showed contiguous involvement of two or more vertebral bodies. An intraspinal or paraspinal soft-tissue mass or abscess was present in 98%. Subligamentous extension was noted in 64% of patients. Gadolinium was administered in 26 patients. Ring enhancement of the soft-tissue mass was shown in 65% of these. Subligamentous enhancement was shown in 35% and bone enhancement was shown in 100% of patients. Follow-up MRI performed in 16 patients showed progressive bone destruction in 10 patients, progressive kyphosis in 2 patients and progression of soft-tissue disease in 4 patients.Conclusions. We have demonstrated an advanced pattern of TBS in this childhood population, which supports other reports that describe a more aggressive process in children. Kyphosis and cord compressions were the most common complications. The use of gadolinium is promising in detecting disease earlier, as it invariably results in bone enhancement and may assist in making the diagnosis when the rim-enhancing pattern of the soft-tissue mass is demonstrated. Follow-up imaging with MRI is a suitable way of assessing resolution of cord compression and decrease in size of the soft-tissue mass. Therefore, considering the pattern of involvement in children with TBS demonstrated by this study, MRI is considered an ideal modality for

  19. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.

    1990-11-01

    In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

  20. Impact of New Gadolinium Cross Sections on Reaction Rate Distributions in 10 * 10 BWR Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Perret, G.; Murphy, M.F.; Jatuff, F.; Chawla, R. [Paul Scherrer Inst, CH-5232 Villigen, (Switzerland); Sublet, J.Ch.; Bouland, O. [DEN, Commissariat Energie Atom, F-13108 St Paul Les Durance, (France); Chawla, R. [Ecole Polytech Fed Lausanne, CH-1015 Lausanne, (Switzerland)

    2009-07-01

    Radial distributions of the total fission rate and the {sup 238}U-capture-to-total-fission (C{sub 8}/F{sub tot}) ratio were measured in SVEA-96+ and SVEA-96 Optima2 assemblies during the LWR-PROTEUS program. Fission rates predicted using MCNPX with JEFF-3.1 cross sections underestimated the measured values in the gadolinium-poisoned pins of the SVEA-96 Optima2 assembly; similarly, C{sub 8}/F{sub tot} ratios were overestimated in some gadolinium-poisoned pins of the SVEA-96+ assembly. A considerable effort was invested at the Paul Scherrer Institut to explain the discrepancies in gadolinium pins, without success. Recently, gadolinium cross sections were measured at the Rensselaer Polytechnic Institute by Leinweber et al. and differed significantly from current library values. ENDF/B-VII.0 gadolinium cross sections have currently been modified to include the new measurements, and these data have been processed with NJOY to yield files usable by MCNPX. Fission rates in the gadolinium-poisoned fuel pins of the SVEA-96 Optima2 pins were increased by 1.4 to 2.0% using the newly produced cross sections, yielding to a better agreement with the experimental values. Predicted C{sub 8}/F{sub tot} ratios were decreased on average by 1.7% in both clustered and un-clustered groups of gadolinium-poisoned fuel pins of the SVEA-96+ assembly correcting the over predictions previously reported in the clustered gadolinium pins. Earlier reported discrepancies observed in PROTEUS integral experiments, between measured and calculated reaction rates in the gadolinium-poisoned pins, might thus be due to inaccurate gadolinium cross sections. The PROTEUS results support the new thermal and epithermal gadolinium data measured by Leinweber et al. (authors)

  1. Mechanisms of oxide dissolution by acid chelating agents

    International Nuclear Information System (INIS)

    Blesa, M.A.; Maroto, A.J.G.

    1982-01-01

    In this paper, the different possible rate controlling processes in the dissolution of metallic oxides are examined. In particular, the following situations are assessed: mass-transfer control; coupling of mass-transfer and reactions at the interface; interface equilibration with the solution; various interface disruption and reconstruction phenomena. For each of the above mentioned cases, the influence of variables such as reagent concentration, temperature, pH, fluid hydrodynamics and general and specific catalysts is discussed. Depending upon the particular situation it is found that a more rational basis for the development of reagent is given by these considerations. The influence of chelating agents on both the thermodynamics and kinetics of the process is discussed, and the results of experimental studies in batch on magnetite and various ferrites are presented and discussed. For this purpose, several reagents were studied, including some very effective ones like thioglycolic acid, and others commonly used in actual decontamination, like ethylenediaminetetraacetic acid and oxalic acid. The relation to other (reductive) chemical decontamination procedures is discussed. The relevance of these studies to decontamination of metallic surfaces is discussed

  2. Synthesis and spectroscopic investigations of hydroxyapatite using a green chelating agent as template

    Science.gov (United States)

    Gopi, D.; Bhuvaneshwari, N.; Indira, J.; Kavitha, L.

    2013-03-01

    Hydroxyapatite [Ca10(PO4)6(OH)2, HAP] particles have been successfully synthesized by a cost-effective, eco-friendly green template method using natural and commercially available sucrose as a chelating agent. The sucrose used in this method has been extracted from various sources, three from natural and one from commercially available sources are exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology. Spectral characterizations involving Fourier transform infrared spectroscopy (FT-IR) for the functional group analysis of sucrose and HAP; carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of the carbon atoms in sucrose and in HAP; liquid chromatography/mass spectrometry (LC-MS) for the determination of the hydrolyzed products of sucrose; and X-ray diffraction (XRD) techniques for the phase identification of the HAP particles were performed. The morphology of the HAP particles were assessed thoroughly using a scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The experimental results indicate that the obtained HAP using the natural sucrose as a chelating agent is of phase pure, with a well defined morphology having discrete particles without any agglomeration than the HAP from commercially available sucrose. Further, the reduced particle size can be achieved from the stem sugarcane extract as the source of the chelating agent.

  3. Synthesis and spectroscopic investigations of hydroxyapatite using a green chelating agent as template.

    Science.gov (United States)

    Gopi, D; Bhuvaneshwari, N; Indira, J; Kavitha, L

    2013-03-01

    Hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2), HAP] particles have been successfully synthesized by a cost-effective, eco-friendly green template method using natural and commercially available sucrose as a chelating agent. The sucrose used in this method has been extracted from various sources, three from natural and one from commercially available sources are exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology. Spectral characterizations involving Fourier transform infrared spectroscopy (FT-IR) for the functional group analysis of sucrose and HAP; carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of the carbon atoms in sucrose and in HAP; liquid chromatography/mass spectrometry (LC-MS) for the determination of the hydrolyzed products of sucrose; and X-ray diffraction (XRD) techniques for the phase identification of the HAP particles were performed. The morphology of the HAP particles were assessed thoroughly using a scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The experimental results indicate that the obtained HAP using the natural sucrose as a chelating agent is of phase pure, with a well defined morphology having discrete particles without any agglomeration than the HAP from commercially available sucrose. Further, the reduced particle size can be achieved from the stem sugarcane extract as the source of the chelating agent. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Soft chelating irrigation protocol optimizes bonding quality of Resilon/Epiphany root fillings.

    Science.gov (United States)

    De-Deus, Gustavo; Namen, Fátima; Galan, João; Zehnder, Matthias

    2008-06-01

    This study was designed to test the impact of either a strong (MTAD) or a soft (1-hydroxyethylidene-1, 1-bisphosphonate [HEPB]) chelating solution on the bond strength of Resilon/Epiphany root fillings. Both 17% EDTA and the omission of a chelator in the irrigation protocol were used as reference treatments. Forty extracted human upper lateral incisors were prepared using different irrigation protocols (n = 10): G1: NaOCl, G2: NaOCl + 17% EDTA, G3: NaOCl + BioPure MTAD (Dentsply/Tulsa, Tulsa, OK), and G4: NaOCl + 18% HEPB. The teeth were obturated and then prepared for micropush-out assessment using root slices of 1 mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey multiple comparisons were used to compare the results among the experimental groups. EDTA- and MTAD-treated samples revealed intermediate bond strength (0.3-3.6 MPa). The lowest bond strengths were achieved in NaOCl-treated samples (0.3-1.2 MPa, p < 0.05). The highest bond strength was reached in the HEBP-treated samples (3.1-6.1 MPa, p < 0.05). Under the present in vitro conditions, the soft chelating irrigation protocol (18% HEBP) optimized the bonding quality of Resilon/Epiphany (Resilon Research LLC, Madison, CT) root fillings.

  5. Curcumin induces apoptosis and protective autophagy in castration-resistant prostate cancer cells through iron chelation

    Directory of Open Access Journals (Sweden)

    Yang C

    2017-02-01

    Full Text Available Chunguang Yang,1,* Xueyou Ma,1,* Zhihua Wang,1 Xing Zeng,1 Zhiquan Hu,1 Zhangqun Ye,1 Guanxin Shen2 1Department of Urology, Tongji Hospital, 2Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China *These authors contributed equally to this work Background: Curcumin induces apoptosis and autophagy in different cancer cells. Moreover, chemical and biological experiments have evidenced that curcumin is a biologically active iron chelator and induces cytotoxicity through iron chelation. We thus hypothesized that curcumin may induce apoptosis and autophagy in castration-resistant prostate cancer (CRPC cells through its iron-chelating properties.Materials and methods: CRPC cells were loaded with curcumin alone or in combination with ferric ammonium citrate (FAC. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. Apoptosis was assessed by flow cytometry, terminal deoxynucleotidyl transferase nick end labeling (TUNEL assay and caspase activity. Autophagy status was analyzed by the detection of autophagosomes and light chain 3-II (LC3-II using transmission electron microscopy and Western blot. Iron-binding activity of curcumin was assessed by spectrophotometry and MTT assay. The expression levels of transferrin receptor 1 (TfR1 and iron regulatory protein 1 (IRP1 were examined by Western blot.Results: Curcumin induced apoptosis and autophagy in CRPC cells. Combining curcumin with autophagy inhibitors (3-methyladenine [3-MA] synergized the apoptotic effect of curcumin. Moreover, curcumin bound to FAC at a ratio of ~1:1, as assessed by spectrophotometry and MTT assay. Apoptosis and autophagy induced by curcumin were counteracted by equal amounts of FAC. At apoptosis- and autophagy-inducing concentrations, curcumin enhanced the expression levels of TfR1 and IRP1, indicative of iron deprivation induced by curcumin

  6. Gadolinium-enhanced excretory MR urography: comparison with MR urography using HASTE technique

    International Nuclear Information System (INIS)

    Jin, Gong Yong; Lee, Jeong Min; Han, Young Min; Cheong, Gyung Ho; Oh, Hee Sul; Kim, Chong Soo; Park, Sung Kwang; Kim, Young Gon

    2000-01-01

    To compare the feasibility of gadolinium-enhanced excretory MR urography (GEMRU) and conventional MR urography using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in patients with hydronephrosis or non-visualized kidney. Fifteen patients with hydronephrosis or non-visualized kidney, as demonstrated by ultrasonography or intravenous urography, were enrolled in this study. Nine were men and six were women, and their age ranged from 18 to 77 (mean, 60.6) years. For all MR examinations, a 1.5T MR unit was employed. For breath-hold MR urography, the HASTE technique (MRU) was used, and reconstruction involved the use of a maximum intensity-projection (MIP) algorithm. For gadolinium-enhanced excretory MR urography, the fast low angle shot (FLASH) 3-D method was used and images were obtained at 5, 10, 20, and 30 minutes, and reconstruction again involved the use of MIP algorithm. In some cases, additional GEMRU was obtained 24 hour after contrast material injection, and an MIP algorithm was used for reconstruction. MRU and GEMRU were independently interpreted by two radiologists who for quantitative analysis compared SNR with CNR, and at each anatomic level qualitatively analyzed morphologic accuracy and diagnostic value of the lesions. In quantitative analysis, SNR and CNR differences between the two sequences at the renal pelvis and the level of the ureter were not significant (p greater than 0.05). In qualitative analysis, GEMRU was superior to MRU for the assessment of evaluated ureter at each level (p less than 0.05), anatomic anomaly and intrinsic tumor. Ureteral stones, however, were more easily diagnosed with MRU. For assessment of the ureter GEMRU is superior to MRU and has the advantage of evaluating renal function. We believe that for evaluation of the urinary tract, especially the distal ureter, GEMRU may be a valuable adjunct to routine MR urography. (author)

  7. Gadolinium enhances the sensitivity of SW-1573 cells for thermal neutron irradiation

    NARCIS (Netherlands)

    Franken, N. A. P.; Bergs, J. W. J.; Kok, T. T.; Kuperus, R. R. N.; Stecher-Rasmussen, F.; Haveman, J.; van Bree, C.; Stalpers, L. J. A.

    2006-01-01

    Gadolinium neutron capture therapy (Gd-NCT) is an experimental cancer treatment based on the physical principal that neutron capture by gadolinium-157 ensures the release of focal high-dose radiation, such as gamma-rays and electrons. Survival and induction of chromosomal aberrations of human

  8. Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination

    Science.gov (United States)

    2016-06-01

    Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination Distribution Statement A. Approved for public release; distribution is...Final Technical Report BRBAA08-Per5-Y-1-2-0030 Title: “Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination ” Grant...Analysis  .............................................................................................  23   6.   Gamma-ray Discrimination

  9. Late gadolinium enhancement and adverse outcomes in a contemporary cohort of adult survivors of tetralogy of Fallot.

    Science.gov (United States)

    Dobson, Richard J; Mordi, Ify; Danton, Mark H; Walker, Niki L; Walker, Hamish A; Tzemos, Nikolaos

    2017-01-01

    Myocardial fibrosis has been associated with poorer outcomes in tetralogy of Fallot, however only a handful of studies have assessed its significance in the current era. Our aim was to quantify the amount of late gadolinium enhancement in both the LV and RV in a contemporary cohort of adults with surgically repaired tetralogy of Fallot, and assess the relationship with adverse clinical outcomes. Single centre cohort study SETTING: National tertiary referral center Patients: One hundred fourteen patients with surgically repaired tetralogy of Fallot with median age 29.5 years (range 17.5-64.2). Prospective follow-up for mean 2.4 years (SD 1.29). Cardiovascular magnetic resonance was performed, and late gadolinium enhancement mass was estimated for the LV using the 5-SD remote myocardium method, and for the RV using a segmental scoring system. Cohort characterization was determined through the use of a computerized database. Survival analysis from time of scan to first adverse event, defined as an episode of atrial arrhythmia, sustained ventricular arrhythmia, hospitalization with heart failure, or implantable cardioverter-defibrillator insertion. Eleven patients experienced an adverse outcome in the follow-up period, although there were no deaths. LV late gadolinium enhancement was associated with adverse outcomes in a univariate model (P = .027). However, when adjusted for age at scan the significant variables included NYHA class (P = .006), peak oxygen uptake (P = .028), number of prior sternotomies (P = .044), and higher indexed RV and LV end diastolic volumes (P = .002 and P tetralogy of Fallot survivors, however assessment particularly of the LV holds promise for the future. © 2016 Wiley Periodicals, Inc.

  10. Legg-Perthes-Calve disease: staging by MRI using gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Ducou le Pointe, H. (Dept. of Pediatric Radiology, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France)); Haddad, S. (Dept. of Pediatric Radiology, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France)); Silberman, B. (Dept. of Pediatric Radiology, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France)); Filipe, G. (Dept. of Orthopedic Surgery, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France)); Monroc, M. (Dept. of Pediatric Radiology, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France)); Montagne, J.P. (Dept. of Pediatric Radiology, Hopital d' Enfants Armand-Trousseau, 75 - Paris (France))

    1994-04-01

    Twenty-one patients (26 hips) with typical signs of Legg-Perthes-Calve (LPC) disease on plain radiographs were explored by MRI. Patients were imaged with a 0.5 T MR unit. Gadolinium-enhanced spinecho MR images were obtained after nonenhanced T1-weighted (spin-echo) and T2[sup *]-weighted (gradient-echo) images. Four different areas were identified in the femoral epiphysis (necrosis, regenerative, cartilaginous and normal fatty bone tissue). The histological evolution of LPC is well described by Catterall and others. Comparing their descriptions with out MR findings, we suggest classification ofLPC into five phases: necrosis: regeneration, reconstruction, reossification and sequelae. (orig.)

  11. Gadolinium-enhanced MR imaging in evaluation of Bell palsy

    International Nuclear Information System (INIS)

    Wang, A.M.; Wesolowski, D.P.; Bojrab, D.I.; Ernstoff, R.M.; Farah, J.

    1989-01-01

    Eight patients with Bell palsy were evaluated with Gd-DTPA (Magnevist)-enhanced MR imaging in a 1.0-T Siemen's Magnetom unit. Axial pre-and postcontrast and coronal postcontrast T1-weighted MR images of facial nerves were studied. Significant unilateral enhancement of the facial nerve within the internal auditory canal, with or without involvement of the geniculate ganglia, was found in six patients. Three of these patients without satisfactory response to medical treatment underwent surgical decompression, with excellent recovery of facial nerve function. The authors believe that gadolinium-enhanced MR imaging is valuable in the evaluation and management of Bell palsy

  12. Serial MRI studies using gadolinium DTPA in active multiple sclerosis

    International Nuclear Information System (INIS)

    Miller, D.H.; Johnson, G.; Barnes, D.; Rudge, P.; McDonald, W.I.

    1988-01-01

    It has been suggested that blood brain barrier (BBB) impairment is a necessary early event in the pathogenesis of the multiple sclerosis (MS) lesions. To evaluate such an hypothesis in vivo would require: (1) serial imaging studies using a modality with high sensitivity for detecting plaques; (2) a contrast enhancing agent which demonstrates BBB impairment. A serial magnetic resonance imaging (MRI) study was undertaken of a group of MS patients using the contrast agent gadolinium-DTPA. As it has been suggested that T 1 and T 2 relaxation times are longer in acute than chronic MS lesions, these were also measured. 3 refs.; 1 figure

  13. Production and characterization of quality gadolinium oxide nanoparticles

    International Nuclear Information System (INIS)

    Hazarika, Samiran; Mohanta, Dambarudhar

    2013-01-01

    Rare earth system Gadolinium (Gd), in either pure form or oxide form, is highly stable against environmental attack. It has immense potential as a contrast agent in magnetic resonance imaging (MRI) devices. Being mechanically and thermally stable it is always difficult to obtain Gd 2 O 3 nanopowders directly from its bulk counterpart using conventional top-down approach. Recently, we have reported production of Gd 2 O 3 nanopowders by first converting bulk Gd 2 O 3 into a nitrate compound and subsequently reduced into a hydroxide product and finally to the oxide product (nanopowder form)

  14. Studies of MRI relaxivities of gadolinium-labeled dendrons

    Science.gov (United States)

    Pan, Hongmu; Daniel, Marie-Christine

    2011-05-01

    In cancer detection, imaging techniques have a great importance in early diagnosis. The more sensitive the imaging technique and the earlier the tumor can be detected. Contrast agents have the capability to increase the sensitivity in imaging techniques such as magnetic resonance imaging (MRI). Until now, gadolinium-based contrast agents are mainly used for MRI, and show good enhancement. But improvement is needed for detection of smaller tumors at the earliest stage possible. The dendrons complexed with Gd(DOTA) were synthesized and evaluated as a new MRI contrast agent. The longitudinal and transverse relaxation effects were tested and compared with commercial drug Magnevist, Gd(DTPA).

  15. Studies on polyaspartamide gadolinium complexes as potential magnetic resonance imaging contrast agents

    International Nuclear Information System (INIS)

    Yan Guoping; Liu Maili; Li Liyun

    2005-01-01

    Purpose: A series of polyaspartamide gadolinium complexes containing pyridoxamine groups were studied as the potential magnetic resonance imaging (MRI) contrast agents for liver enhancement. Methods: These polyaspartamide gadolinium complexes were prepared and evaluated by relaxivity, acute toxicity studies and magnetic resonance imaging of the liver in rats. Results: These polyaspartamide gadolinium complexes have higher relaxation effectiveness than that of the clinically used gadolinium diethylenetriaminepentaacetic acid and possess the low intravenous acute toxicities to Institute for Cancer Research (ICR) mice. Magnetic resonance imaging of the liver in rats indicated that they greatly enhance the contrast of magnetic resonance images and provide prolonged intravascular duration in the liver. Conclusion: These results indicated that the polyaspartamide gadolinium complexes containing pyridoxamine groups could be considered as the appropriate MRI contrast agents for liver enhancement

  16. Enhancements in hepatobiliary imaging: the spectrum of gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid usages in hepatobiliary magnetic resonance imaging.

    Science.gov (United States)

    Channual, Stephanie; Pahwa, Anokh; Lu, David S; Raman, Steven S

    2016-09-01

    Gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a unique hepatocyte-specific contrast agent approved for clinical use in the United States in 2008. Gd-EOB-DTPA-enhanced MR has shown to improve detection and characterization of hepatic lesions. Gd-EOB-DTPA is now being routinely used in daily clinical practice worldwide. Therefore, it is important for radiologists to be familiar with the potential uses and pitfalls of Gd-EOB-DTPA, which extends beyond the assessment of focal hepatic lesions. The purpose of this article is to review the various usages of Gd-EOB-DTPA in hepatobiliary MR imaging.

  17. To chelate or not to chelate in MDS: That is the question!

    Science.gov (United States)

    Zeidan, Amer M; Griffiths, Elizabeth A

    2018-03-08

    Myelodysplastic syndromes (MDS) are a heterogeneous group of hemopathies that exhibit physical manifestations with clinical consequences of bone marrow failure and inherent risk of progression to acute myeloid leukemia. Iron overload (IO) is common in MDS due to chronic transfusion support and disease-related alterations in iron metabolism. IO has been conclusively associated with inferior outcomes among MDS patients. Despite lack of randomized trials showing a survival impact of iron chelation therapy (ICT), ICT is recommended by experts and guidelines for select MDS patients with IO and is often used. The availability of effective oral ICT agents has reignited the controversy regarding ICT use in patients with MDS and IO. Here we summarize the studies evaluating the value of ICT in MDS and suggest a practical approach for use of these therapies. We also highlight controversies regarding use of ICT in MDS and discuss some ongoing efforts to answer these questions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. In vitro and in vivo evaluation of potential aluminum chelators.

    Science.gov (United States)

    Graff, L; Muller, G; Burnel, D

    1995-10-01

    The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

  19. The adsorption of chelating reagents on oxide minerals

    International Nuclear Information System (INIS)

    Bryson, M.A.W.

    1984-06-01

    This work constitutes a fundamental study of the interaction between chelating reagents and oxide minerals. The adsorption mechanisms have been elucidated for most of the systems generated by the oxides of copper(II) or iron(III) and chelating reagents octyl hydroxamate, N-phenylbenzohydroxamate, salicylaldoxime, 5-nitro-salicylaldoxime or 8-hydroxyquinoline. In order to better understand the adsorption process associated with copper(II) oxide, the oxide was recrystallized to produce a coarser material with a more uniform surface. This allowed the oxide surface to be viewed under the scanning electron microscope. A detailed investigation of the effect of the system variables; pH, conditioning period, concentration, temperature, surface area and dispersing reagent on the rate of precipitation of the copper chelate species of general form, Cu(chel) 2 , was made. In addition the chemical nature of the adsorbed species and the structural form of the precipitates were determined with the aid of infra-red spectroscopy and the scanning electron microscope. On the basis of these results a model has been formulated for the adsorption processes. The precipitation process was examined in more detail by the study of the adsorption of chelate on copper metal. Contact angle measurements of air bubbles on copper metal conditioned with chelate were related to the adsorption results in an attempt to isolate the optimum conditions for flotation of oxide minerals

  20. Breath-hold gadolinium-enhanced MRA : clinical application

    International Nuclear Information System (INIS)

    Kang, Sung Gwon; Kang, Ji Hee; Kim, Won Hong; Lim, Myung Kwan; Cho, Young Kook; Cho, Soon Gu; Suh, Chang Hae

    1998-01-01

    The purpose of this study is to compare breath-hold gadolinium enhanced MR angiography (MRA) with digital subtraction angiography. Ten patients underwent angiography and breath-hold gadolinium enhanced MRA; the latter performed at 1.5T with 3D FSPGR after a bolus injection of gadopentetate dimeglumine (0.4m mol/kg). Seven of ten pathologic conditions (70%) evaluated by both techniques had a similar appearance. The conditions examined were as follows: the artery feeding renal cell carcinoma(n=2); renal artery stenosis (n=2); pulmonary AVM(n=2); abdominal aortic aneurysm (n=1); atheromatous plaque in the lower abdominal aorta (n=1); an enlarged bronchial artery (n=1); and an aberrant renal artery (n=1). For evaluating an anatomic relationship, a reconstructed 3D image obtained by MRA is more advantageous. Breath hold contrast enhanced MRA is a potentially useful noninvasive screening method for detecting vascular abnormality of the aorta and its branches. (author). 13 refs., 1 tab., 4 figs

  1. Breath-hold gadolinium-enhanced MRA : clinical application

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Gwon; Kang, Ji Hee; Kim, Won Hong; Lim, Myung Kwan; Cho, Young Kook; Cho, Soon Gu; Suh, Chang Hae [Inha University Hospital, Inchon (Korea, Republic of)

    1998-05-01

    The purpose of this study is to compare breath-hold gadolinium enhanced MR angiography (MRA) with digital subtraction angiography. Ten patients underwent angiography and breath-hold gadolinium enhanced MRA; the latter performed at 1.5T with 3D FSPGR after a bolus injection of gadopentetate dimeglumine (0.4m mol/kg). Seven of ten pathologic conditions (70%) evaluated by both techniques had a similar appearance. The conditions examined were as follows: the artery feeding renal cell carcinoma(n=2); renal artery stenosis (n=2); pulmonary AVM(n=2); abdominal aortic aneurysm (n=1); atheromatous plaque in the lower abdominal aorta (n=1); an enlarged bronchial artery (n=1); and an aberrant renal artery (n=1). For evaluating an anatomic relationship, a reconstructed 3D image obtained by MRA is more advantageous. Breath hold contrast enhanced MRA is a potentially useful noninvasive screening method for detecting vascular abnormality of the aorta and its branches. (author). 13 refs., 1 tab., 4 figs.

  2. Gadolinium-hydrogen ion exchange of zirconium phosphate

    Science.gov (United States)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  3. Bifunctional chelates of Rh-105 and Au-199 as potential radiotherapeutic agents

    International Nuclear Information System (INIS)

    Troutner, D.E.; Schlemper, E.O.

    1990-01-01

    Since last year we have: continued the synthesis of pentadentate bifunctional chelating agents based on diethylene triamine; studied the chelation Rh-105, Au-198 (as model for Au-199) and Tc-99m with these agents as well as chelation of Pd-109, Cu-67, In-111, and Co-57 with some of them; synthesized a new class of potential bifunctional chelating agents based on phenylene diamine; investigated the behavior of Au-198 as a model for Au-199; begun synthesis of bifunctional chelating agents based on terpyridly and similar ligands; and continued attempts to produce tetradentate bifunctional chelates based on diaminopropane. Each of these will be addressed in this report

  4. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Schlegel, P.

    1981-01-01

    Albumin microspheres have been synthesized with EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after 24 hr in 50% plasma at 37 0 C, whereas with DTPA microspheres the label shows no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +- 16)% of the activity localizes in the lungs at 5 min, with (60 +- 7)% remaining after 2 h. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  5. Evaluation of macrocyclic hydroxyisophthalamide ligands as chelators for zirconium-89.

    Science.gov (United States)

    Bhatt, Nikunj B; Pandya, Darpan N; Xu, Jide; Tatum, David; Magda, Darren; Wadas, Thaddeus J

    2017-01-01

    The development of bifunctional chelators (BFCs) for zirconium-89 immuno-PET applications is an area of active research. Herein we report the synthesis and evaluation of octadentate hydroxyisophthalamide ligands (1 and 2) as zirconium-89 chelators. While both radiometal complexes could be prepared quantitatively and with excellent specific activity, preparation of 89Zr-1 required elevated temperature and an increased reaction time. 89Zr-1 was more stable than 89Zr-2 when challenged in vitro by excess DTPA or serum proteins and in vivo during acute biodistribution studies. Differences in radiometal complex stability arise from structural changes between the two ligand systems, and suggest further ligand optimization is necessary to enhance 89Zr chelation.

  6. Evaluation of macrocyclic hydroxyisophthalamide ligands as chelators for zirconium-89.

    Directory of Open Access Journals (Sweden)

    Nikunj B Bhatt

    Full Text Available The development of bifunctional chelators (BFCs for zirconium-89 immuno-PET applications is an area of active research. Herein we report the synthesis and evaluation of octadentate hydroxyisophthalamide ligands (1 and 2 as zirconium-89 chelators. While both radiometal complexes could be prepared quantitatively and with excellent specific activity, preparation of 89Zr-1 required elevated temperature and an increased reaction time. 89Zr-1 was more stable than 89Zr-2 when challenged in vitro by excess DTPA or serum proteins and in vivo during acute biodistribution studies. Differences in radiometal complex stability arise from structural changes between the two ligand systems, and suggest further ligand optimization is necessary to enhance 89Zr chelation.

  7. Inositol hexa-phosphate: a potential chelating agent for uranium

    International Nuclear Information System (INIS)

    Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A.

    2007-01-01

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  8. Quantitative structure-property relationship (correlation analysis) of phosphonic acid-based chelates in design of MRI contrast agent.

    Science.gov (United States)

    Tiwari, Anjani K; Ojha, Himanshu; Kaul, Ankur; Dutta, Anupama; Srivastava, Pooja; Shukla, Gauri; Srivastava, Rakesh; Mishra, Anil K

    2009-07-01

    Nuclear magnetic resonance imaging is a very useful tool in modern medical diagnostics, especially when gadolinium (III)-based contrast agents are administered to the patient with the aim of increasing the image contrast between normal and diseased tissues. With the use of soft modelling techniques such as quantitative structure-activity relationship/quantitative structure-property relationship after a suitable description of their molecular structure, we have studied a series of phosphonic acid for designing new MRI contrast agent. Quantitative structure-property relationship studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors of the phosphonic acid-based chelating agent and their stability constants. The final quantitative structure-property relationship mathematical models were found as--quantitative structure-property relationship Model for phosphonic acid series (Model 1)--log K(ML) = {5.00243(+/-0.7102)}- MR {0.0263(+/-0.540)}n = 12 l r l = 0.942 s = 0.183 F = 99.165 quantitative structure-property relationship Model for phosphonic acid series (Model 2)--log K(ML) = {5.06280(+/-0.3418)}- MR {0.0252(+/- .198)}n = 12 l r l = 0.956 s = 0.186 F = 99.256.

  9. Low concentration of a Gd-chelate increases the signal-to-noise ratio in fast pulsing BEST experiments

    Science.gov (United States)

    Sibille, Nathalie; Bellot, Gaëtan; Wang, Jing; Déméné, Hélène

    2012-11-01

    Despite numerous developments in the past few years that aim to increase the sensitivity of NMR multidimensional experiments, NMR spectroscopy still suffers from intrinsic low sensitivity. In this report, we show that the combination of two developments in the field, the Band-selective Excitation Short-Transient (BEST) experiment [Schanda et al., J. Am. Chem. Soc., 128 (2006) 9042] and the addition of the nonionic paramagnetic gadolinium chelate gadodiamide into NMR samples, enhances the signal-to-noise ratio. This effect is shown here for four different proteins, three globular and one unfolded, of molecular weights ranging from 6.5 kDa to 40 kDa, using 2D BEST HSQC and 3D BEST triple resonance sequences. Moreover, we show that the increase in signal-to-noise ratio provided by the gadodiamide is higher for peak resonances with lower than average intensity in BEST experiments. It is interesting to note that these residues are on average the weakest ones in those experiments. In this case, the gadodiamide-mediated increase can reach a value of 60% for low and 30% for high molecular weight proteins respectively. An investigation into the origin of this “paramagnetic gain” in BEST experiments is presented.

  10. Protracted chelate therapy after incorporation of plutonium 239 in rats

    International Nuclear Information System (INIS)

    Gemenetzis, E.

    1976-01-01

    The author has tested in how far 239 Pu can be mobilized by Ca and Zn, Desfenioxamin B(DFDA) and by combined doses of Ca-DTPA and DFDA. The pre-experiment covered the 239 Pu-metabolism in untreated male and female rats and the distribution in dependence of the way of application. If treatment is started immediately by multiple chelate doses, the first two injections play the main part in the decorporation of 239 Pu. The combination Ca-DTPA30 + DFDA30 μMol x kg -1 is proved to be the best means of decorporation for the whole body. The efficiency of another therapy depends essentially on the treatment used, a daily treatment showing the best effects. If treatment is started later with multiple chelate doses, the total decorporation efficiency is of less value, especially in the skeleton. Aequimolar doses of Ca-DTPA and Zn-DTPA have the same degree of efficiency. This indicates that during protracted chelate treatment starting later, Ca-DTPA could be substituted by the less toxic Zn-DTPA after incorporation of 239 Pu. These results show that intermittant administration of the week's dose is more efficient than a single chelate administration of the whole week's dose at once. Permanent chelate infusion does not seem necessary in any case since it has the same effect as 3 to 5 injections per week and is difficult to carry out in medical practice. Thus, it seems advisable to divide up the weekly dose into 3-5 injections. In case of a wound contamination, the efficiency of immediate intensive treatment depends on the 239 Pu compound used, on the chelate used, and on its dosage. (orig.) [de

  11. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    Science.gov (United States)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  12. Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

    International Nuclear Information System (INIS)

    Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha; Flora, Swaran J.S.

    2009-01-01

    Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

  13. Interaction of chelating agents with cadmium in mice and rats

    International Nuclear Information System (INIS)

    Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

    1984-01-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl 2 and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl 2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl 2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes

  14. Interaction of chelating agents with cadmium in mice and rats.

    Science.gov (United States)

    Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

    1984-01-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

  15. Myocardial Impairment Detected by Late Gadolinium Enhancement in Hypertrophic Cardiomyopathy: Comparison with 99mTc-MIBI/Tetrofosmin and 123I-BMIPP SPECT

    OpenAIRE

    Hashimura, Hiromi; Kiso, Keisuke; Yamada, Naoaki; Kono, Atsushi; Morita, Yoshiaki; Fukushima, Kazuto; Higashi, Masahiro; Noguchi Teruo; Ishibashi-Ueda, Hatsue; Naito, Hiroaki; Sugimura, Kazuro

    2013-01-01

    Purpose: Myocardial fibrosis is considered to be an important factor in myocardial dysfunction and sudden cardiac death in hypertrophic cardiomyopathy (HCM). The purpose of this study was to compare myocardial fibrosis detected by late gadolinium enhancement (LGE) on cardiac MRI with myocardial perfusion and fatty acid metabolism assessed by single photon emission computed tomography in HCM.Materials and Methods: We retrospectively evaluated 20 consecutive HCM patients (female, 7; mean age, 5...

  16. Chelation therapy in intoxications with mercury, lead and copper

    DEFF Research Database (Denmark)

    Cao, yang; Skaug, Marit Aralt; Andersen, Ole

    2015-01-01

    In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid...

  17. Potentiometric study of Nd3+ chelates of substituted salicylhydroxamic acids

    International Nuclear Information System (INIS)

    Deshpande, R.G.; Jahagirdar, D.V.

    1976-01-01

    The interaction of Nd 3+ ion with salicylhydroxamic acid and 5-methyl, 5-chloro, 5-bromo, 5-nitro, 4-chloro, 4-bromo and 3-chloro salicylhydroxamic acids is investigated potentiometrically by Calvin-Bjerrum titration technique at 30 0 +- 0.1 0 and ionic strength μ=0.1 M(NaClO 4 ) in 50% v/v dioxane-water mixtures. Nd 3+ forms only 1:1 chelates with these ligands. The validity of the log K= apk + b relationship is examined for these chelates. (author)

  18. Long-term retention of gadolinium in the skin of rodents following the administration of gadolinium-based contrast agents

    International Nuclear Information System (INIS)

    Pietsch, Hubertus; Jost, Gregor; Frenzel, Thomas; Huetter, Joachim; Sieber, Martin A.; Lengsfeld, Philipp

    2009-01-01

    Several publications suggest a potential association between the administration of Gadolinium-based contrast agents (GBCAs) and the onset of a rare but serious disease, Nephrogenic Systemic Fibrosis (NSF). The aim of this study was to determine the elimination time-course of Gadolinium (Gd) from skin tissue after application of GBCAs in rats. Seven different marketed GBCAs were injected on five consecutive days at a dose of 2.5 mmol/kg bodyweight into the tail vein of Han-Wistar rats and the Gd concentrations were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in skin biopsies taken at various time-points up to a year after the last injection. Most of the administered Gd was eliminated from the skin within a time-period of about 2 months. However, the repeated administration of linear GBCAs resulted in long-term retention of a small portion of the administered Gd in the skin tissue of rats, with substantially higher values observed in animals treated with non-ionic linear agents than in those that received ionic linear GBCAs. Following treatment with macrocyclic GBCAs, Gd values in the skin were in the same range as observed in the controls from day 24 post-injection onwards. In summary, we observed a correlation between the complex stability of GBCAs and the amount of residual Gd in the skin up to a year after application of GBCAs. (orig.)

  19. Long-term retention of gadolinium in the skin of rodents following the administration of gadolinium-based contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Pietsch, Hubertus; Jost, Gregor; Frenzel, Thomas; Huetter, Joachim; Sieber, Martin A. [Media Research, Bayer Schering Pharma AG Contrast, Berlin (Germany); Lengsfeld, Philipp [Bayer Schering Pharma AG, Global Medical Affairs Diagnostic Imaging, Berlin (Germany)

    2009-06-15

    Several publications suggest a potential association between the administration of Gadolinium-based contrast agents (GBCAs) and the onset of a rare but serious disease, Nephrogenic Systemic Fibrosis (NSF). The aim of this study was to determine the elimination time-course of Gadolinium (Gd) from skin tissue after application of GBCAs in rats. Seven different marketed GBCAs were injected on five consecutive days at a dose of 2.5 mmol/kg bodyweight into the tail vein of Han-Wistar rats and the Gd concentrations were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in skin biopsies taken at various time-points up to a year after the last injection. Most of the administered Gd was eliminated from the skin within a time-period of about 2 months. However, the repeated administration of linear GBCAs resulted in long-term retention of a small portion of the administered Gd in the skin tissue of rats, with substantially higher values observed in animals treated with non-ionic linear agents than in those that received ionic linear GBCAs. Following treatment with macrocyclic GBCAs, Gd values in the skin were in the same range as observed in the controls from day 24 post-injection onwards. In summary, we observed a correlation between the complex stability of GBCAs and the amount of residual Gd in the skin up to a year after application of GBCAs. (orig.)

  20. Assessing the iron chelation capacity of goat casein digest isolates.

    Science.gov (United States)

    Smialowska, A; Matia-Merino, L; Carr, A J

    2017-04-01

    We isolated goat phosphopeptides via calcium and ethanol precipitation from a caseinate digest and investigated their feasibility as an iron-fortification ingredient in nutritional foods. Goat tryptic-digested phosphopeptides could bind 54.37 ± 0.50 mg of Fe/g of protein compared with goat milk, which could bind 3.83 ± 0.01 mg of Fe/g of protein, indicating that isolation did increase iron binding. However, the >13-fold increase in iron binding was only partly explained by the increased concentration of phosphoserine-rich residues in the isolated fraction: we observed a 77% increase in serine residue content and a 5.9-fold increase in phosphorus in the goat peptide isolate compared with the starting caseinate material. We investigated the effect of potential industrial processing conditions (including heating, cooling, holding time, and processing order) on iron binding by the tryptic-digested phosphopeptides. In addition, we tested the effect of ionic strength and the addition of peptides to a milk system to understand how food formulations could affect iron binding. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Influence of the addition of gadolinium on the microstructure and mechanical properties of duplex stainless steel

    International Nuclear Information System (INIS)

    Ahn, Ji-Ho; Jung, Hyun-Do; Im, Jae-Han; Jung, Ki Ho; Moon, Byung-Moon

    2016-01-01

    The aim of this study is to investigate the effects of gadolinium addition on the microstructure and mechanical properties of duplex stainless steel (DSS) fabricated using a normal casting method. The oxygen content in the cast DSS alloy with gadolinium decreased because of the high reactivity of gadolinium with oxygen. The area fraction and size of non-intermetallic inclusions in the alloy decreased from 0.80±0.12% to 0.58±0.04% and from 6.9±0.7 to 5.8±0.4 μm upon gadolinium addition, respectively. Notably, the ultimate tensile strength and strain at break of the cast alloy significantly increased with the addition of gadolinium from 919±25 to 969±8 MPa and from 24.8±1.9% to 28.4±1.1%, respectively. The hardness of the cast alloy with gadolinium increased from 23.6±1.3 to 25.0±1.2 HRC. A significant increase in the impact energy of the cast alloy was observed and the brittle-to-ductile transition temperature slightly decreased by approximately 10 °C with the addition of gadolinium.

  2. Chelating agents improve enzymatic solubilization of pectinaceous co-processing streams

    DEFF Research Database (Denmark)

    Ravn, Helle Christine; Meyer, Anne S.

    2014-01-01

    of different levels of ethylene-diaminetetraacetic acid (EDTA), citric acid, oxalic acid, and phosphate was assessed in relation to enzymatic solubilization of isopropanol precipitatable oligo- and polysaccharides from sugar beet pulp, citrus peel, and two types of potato pulp. The two types of potato pulp...... solubilization yields. The effect of the chelating agents correlated to their dissociation constants (pKa values) and calcium binding constants and citric acid and EDTA exerted highest effects. Maximum polysaccharide yield was obtained for FiberBind 400 where the enzymatic treatment in presence of citric acid...

  3. Metal chelate conjugated monoclonal antibodies, wherein the metal is an α emitter

    International Nuclear Information System (INIS)

    Gansow, O.A.; Strand, M.

    1984-01-01

    Methods of manufacturing and purifying metal chelate conjugated monoclonal antibodies are described, wherein the chelated metal emits alpha radiation. The conjugates are suited for therapeutic uses being substantially free of nonchelated radiometal. (author)

  4. Effect of hydrostatic pressure on magnetic phase transitions and magnetization in gadolinium monocrystal

    International Nuclear Information System (INIS)

    Nikitin, S.A.; Bezdushnyj, R.V.

    1989-01-01

    Effect of hydrostatic pressure on magnetization in gadolinium monocrystal (Δσ-effect) was investigated. Dependences of spesific magnetization, Δσ-effect and bulk magnetostriction of gadolinium monocrystal on temperatures were studied. Results of conducted investigation have shown that in gadolinium the change of specific magnetization under the hydrostatic pressure effect is caused in general case by three effects: a)change of spontaneous magnetization under the effect of hydrostatic pressure; b)change of magnetization within technical magnetization range due to the effect of hydrostatic pressure on magnetic anisotropy constants; c)change of magnetization due to the effect of hydrostatic pressure on temperature of spin-reoriented transition

  5. Chelating ligands: enhancers of quality and purity of biogas ...

    African Journals Online (AJOL)

    The quality of biogas depends largely on the percentage of methane and hydrogen sulphide gas present. High concentration of hydrogen sulphide results in low quality biogas. This work employed the use of chelating ligands in scrubbing hydrogen sulphide gas while improving the yield of methane gas. Experimental ...

  6. Studies on effect of Microbial Iron Chelators on Candida Albican

    International Nuclear Information System (INIS)

    Rehmani, Fouzia S.; Milicent, S.; Zaheer-Uddin

    2005-01-01

    Iron is an essential for the life of all microbe cells. It generally exists in the oxidized form Fe(III). Even under anaerobic reducing condition the metal appear to be taken up as Fe(III). Thus free-living microorganisms require specific and effective ferric ion transport system to cope with low availability of the metal. In iron deficient environment they produce a low molecular weight specific chelators called siderphores or microbial iron chelators. Siderphores compete for limited supplied of iron. These compounds came out of the cell but can not re-enter without iron due to high affinity of these siderphores often have more than one catechol/hydroxamate functions and are multidentate (usually hexadentate ligands). The aim of the present research is to check the effect of iron chelators, namely gallic acid and salisyl hydroxamate on the growth of Candida albican in vitro. C. albican is the opportunistic paltogen present as the normal flora inside human body. In vivo the growth of C. albican is distributed by the use of antibiotics and immuno suppressers. In cases of iron over-dosage in human being, the patients are treated with certain a-iron chelators. Hence an attempt is made to notice the effect that might be inhibition or enhancement of the organism in vitro. (author)

  7. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  8. Chelation of thallium by combining deferasirox and desferrioxamine in rats.

    Science.gov (United States)

    Saljooghi, Amir Shokooh; Babaie, Maryam; Mendi, Fatemeh Delavar; Zahmati, Maliheh; Saljooghi, Zoheir Shokouh

    2016-01-01

    The hypothesis that two known chelators deferasirox (4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing thallium from the body was tested in a new acute rat model. 7-week-old male Wistar rats received chelators: deferasirox (orally), DFO (intraperitoneal; i.p.), or deferasirox + DFO as 75 or 150 mg/kg dose half an hour after a single i.p. administration of 8 mg thallium/kg body weight in the form of chloride. Serum thallium concentration, urinary thallium, and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level, while DFO was more effective than deferasirox in enhancing urinary thallium excretion, deferasirox was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the DFO effect on thallium and DFO did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of thallium chelators. Urinary values were more useful because of the high variability of serum results. © The Author(s) 2013.

  9. Mixed ligand chelate therapy for plutonium and cadmium poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, J; Derr, S K [Hope Coll., Holland, MI (USA)

    1978-09-28

    Some experiments with mice are described in which complete removal of tissue deposits of /sup 239/Pu and prevention of mortality in animals given lethal doses of Cd were achieved using a mixed ligand chelate treatment (MLC). The mixed ligand consisted of diethylenetriaminepentaacetic acid and salicylic acid.

  10. Iron chelating activity, phenol and flavonoid content of some ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... require regular blood transfusions in order to improve both quality of ... fused red blood cells and the excess iron is deposited as ... potentiation of reactive oxygen species (ROS) and .... The percentage inhibition of ferrozine–Fe2+ complex formation was ... estimation of the chelating activity of the coexisting.

  11. MRI evaluation of myometrial invasion by endometrial carcinoma. Comparison between fast-spin-echo T2W and coronal FMPSPGR Gadolinium-Dota-Enhanced Sequences

    International Nuclear Information System (INIS)

    Nasi, Francesca; Fiocchi, Federica; Pecchi, Annarita; Torricelli, Pietro; Rivasi, Francesco

    2005-01-01

    Purpose. The depth of myometrial invasion by endometrial carcinoma strongly affects the incidence of metastasis to regional nodes and influences the surgical strategies. The aim of this paper is to compare the results of FSE T2-w and Gadolinium-enhanced FMPSGR MR sequences in assessing the depth of myometrial invasion by endometrial cancer. Materials and methods. Forty-five women with histopathologically-proven endometrial carcinoma underwent preoperative MRI. Axial SE TI w, axial, sagittal and para-coronal FSE T2w and para-coronal Gadolinium enhanced FMPSGR sequences were performed using a high field strength magnet (1.5T). Within one month of MR all patients underwent hysterectomy, and anatomical evaluation of the surgical specimen was done sectioning the uterus along the short axis. Based upon the results of the histological evaluation the results of the FSE T2w and Gadolinium-enhanced sequences were compared and the statistical difference between the results obtained was statistically evaluated. Results. The histological evaluation showed intra mucosal neoplasm in 11 patients, myometrial infiltration less than 50% in 31 patients, myometrial infiltration more than 50% in 12 patients and transmural cancer 1 patient. Statistical evaluation showed that the FSE T2w sequence had a global sensitivity and specificity of 80.6% and 87.6%, respectively, with a mean Negative Predictive Value of 92.6% and a mean Positive Predictive Value of 86%. Gadolinium-enhanced FMPSPGR sequence had a global sensitivity and specificity of 90.6% and 93.3%, respectively, with a mean Negative Predictive Value of 96,3% and a mean Positive Predictive Value of 88%. The staging accuracy (χ 2 test) on FMPSPGR images (95%) was higher than that on FSE T2w images (78%). Conclusions. In our experience Gadolinium-enhanced dynamic sequences increase the accuracy of MR imaging in diagnosing the depth of myometrial invasion. In particular they improve the visualisation of the inner myometrium, the so

  12. First results on study of gadolinium as burnable absorber

    International Nuclear Information System (INIS)

    Abbate, Maximo J.; Sbaffoni, Maria M.

    2000-01-01

    Following on with the work included in the 'Burnable absorbers research plan' several experiments were carried out oriented to determine Ga 2 O 3 burn up. Cold tests were performed and samples were irradiated in the RA-3 reactor. In this paper, some calculated values are presented together with their comparisons with experimental ones. The parameters foreseen for performing the experiments were verified and also the predictions on burn up of uranium and gadolinium isotopes concentrations. These results imply that the nuclear data of these isotopes included in the library are satisfactory. Next steps will be to measure other isotopes concentrations, gamma spectrum, and the irradiation of one pellet to determine self shielding effects in order to obtain effective cross sections i.e. for CAREM geometry. (author)

  13. Self-consistent, relativistic, ferromagnetic band structure of gadolinium

    International Nuclear Information System (INIS)

    Harmon, B.N.; Schirber, J.; Koelling, D.D.

    1977-01-01

    An initial self-consistent calculation of the ground state magnetic band structure of gadolinium is described. A linearized APW method was used which included all single particle relativistic effects except spin-orbit coupling. The spin polarized potential was obtained in the muffin-tin form using the local spin density approximation for exchange and correlation. The most striking and unorthodox aspect of the results is the position of the 4f spin-down ''bands'' which are required to float just on top of the Fermi level in order to obtain convergence. If the 4f states (l = 3 resonance) are removed from the occupied region of the conduction bands the magnetic moment is approximately .75 μ/sub B//atom; however, as the 4f spin-down states are allowed to find their own position they hybridize with the conduction bands at the Fermi level and the moment becomes smaller. Means of improving the calculation are discussed

  14. Extracellular gadolinium-based contrast media: An overview

    International Nuclear Information System (INIS)

    Bellin, Marie-France; Van Der Molen, Aart J.

    2008-01-01

    Increasing use is made of extracellular MRI contrast agents that alter the image contrast following intravenous administration; they predominantly shorten the T1 relaxation time of tissues. The degree and location of these changes provide substantial diagnostic information. However gadolinium-based contrast agents (Gd-CA) are not inert drugs. They may cause acute non-renal adverse reactions (e.g. anaphylactoid reactions), acute renal adverse reactions (e.g. contrast induced nephropathy), delayed adverse reactions (nephrogenic systemic fibrosis) and problems at the site of injection (e.g. local necrosis). This review describes the current status of Gd-CA, their mechanism of action, chemical structure, pharmacokinetics, dosage, elimination, nephrotoxicity and adverse events

  15. Extracellular gadolinium-based contrast media: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Bellin, Marie-France [University Paris-Sud 11, Department of Radiology, University Hospital Paul-Brousse, AP-HP, 12, Avenue Paul Vaillant-Couturier, 94804 Villejuif Cedex (France)], E-mail: marie-france.bellin@pbr.aphp.fr; Van Der Molen, Aart J. [University Paris-Sud 11, Department of Radiology, University Hospital Paul-Brousse, AP-HP, 12, Avenue Paul Vaillant-Couturier, 94804 Villejuif Cedex (France)

    2008-05-15

    Increasing use is made of extracellular MRI contrast agents that alter the image contrast following intravenous administration; they predominantly shorten the T1 relaxation time of tissues. The degree and location of these changes provide substantial diagnostic information. However gadolinium-based contrast agents (Gd-CA) are not inert drugs. They may cause acute non-renal adverse reactions (e.g. anaphylactoid reactions), acute renal adverse reactions (e.g. contrast induced nephropathy), delayed adverse reactions (nephrogenic systemic fibrosis) and problems at the site of injection (e.g. local necrosis). This review describes the current status of Gd-CA, their mechanism of action, chemical structure, pharmacokinetics, dosage, elimination, nephrotoxicity and adverse events.

  16. Role of gadolinium in MR imaging of sinonasal masses

    International Nuclear Information System (INIS)

    Lanzieri, C.F.; Shah, M.; Smith, A.S.; Tarr, R.; Van Dyke, C.; Kaufman, B.; Krauss, D.; Lavertu, P.

    1990-01-01

    This paper determines whether additional clinically useful information can be obtained with the use of contrast-enhanced MR imaging, compared with nonenhanced MR imaging and enhanced CT, in the evaluation of patients with sinonasal masses. Twenty-one patients with CT evidence of a sinonasal mass were imaged at 1.5 T with T1 and T2 weighting and without and with gadolinium injection. The studies were interpreted independently and correlated with the surgical and pathologic findings. The contrast-enhanced MR images yielded additional clinically useful information in 13 of 21 cases. It was the only way to separate tumor from a mucocele in four of 13 cases. In two of 13 instances, it was the only modality that identified encephalocele as distinct from a tumor. In the remaining seven cases, more accurate delineation of the tumor margins was obtained

  17. Temperature profiles on the gadolinium surface during electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-03-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck`s law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author).

  18. New reduced variant in gadolinium and samarium monoxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bist, B M.S.; Kumar, J; Srivastava, O N [Banaras Hindu Univ. (India). Dept. of Physics

    1977-01-01

    A new reduced phase has been observed in the thin films of gadolinium and samarium monoxides. This phase results on imparting an annealing treatment to the monoxides and is formed as a result of the creation and ordering of vacancies in the oxygen sublattice. The new phase has been analysed to possess a rhombohedral unit cell with lattice parameters a/sub R/ = a/sub 0/ square root of (3/2) and c/sub R/ = a/sub 0/ square root of 3 (based on hexagonal axes, a/sub 0/ being the lattice parameter of the fundamental zinc blende type unit cell of the monoxide). Based on the proposed structure, the new phase can be assigned the solid state chemical formula RO/sub x/ where R = Gd, Sm and x = 0.66.

  19. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok; Da Costa, Pedro M. F. J.; Wolter, Anja U. B.; Maier, Diana; Buechner, Bernd; Hampel, Silke

    2013-01-01

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  20. SWI enhances vein detection using gadolinium in multiple sclerosis

    International Nuclear Information System (INIS)

    Maggi, Pietro; Mazzoni, Lorenzo N; Moretti, Marco; Grammatico, Matteo; Chiti, Stefano; Massacesi, Luca

    2015-01-01

    Susceptibility weighted imaging (SWI) combined with the FLAIR sequence provides the ability to depict in vivo the perivenous location of inflammatory demyelinating lesions – one of the most specific pathologic features of multiple sclerosis (MS). In addition, in MS white matter (WM) lesions, gadolinium-based contrast media (CM) can increase vein signal loss on SWI. This report focuses on two cases of WM inflammatory lesions enhancing on SWI images after CM injection. In these lesions in fact the CM increased the contrast between the parenchyma and the central vein allowing as well, in one of the two cases, the detection of a vein not visible on the same SWI sequence acquired before CM injection

  1. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok

    2013-08-15

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  2. Temperature profiles on the gadolinium surface during electron beam evaporation

    International Nuclear Information System (INIS)

    Ohba, Hironori; Shibata, Takemasa

    1995-01-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck's law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author)

  3. Gadolinium-DTPA enhanced MRI of the brain

    International Nuclear Information System (INIS)

    Hosten, N.; Felix, R.

    1994-01-01

    The text reviews MRI findings in a variety of cerebral diseases. Advantages of Gadolinium-DTPA (Gd-DTPA) enhanced MRI over plain MRI and enhanced CT are discussed. Enhanced MRI is far superior to enhanced CT in the detection of meningeal tumor spread, meningeal inflammation, inflammatory lesions of the optic nerve, brain lesions in multiple sclerosis and infarction. Enhanced MRI is today the most sensitive diagnostic tool in hypophaseal adenomas. Also enhancement of gliomas is detected by MRI with higher sensitivity than by CT. Use Gd-DTPA allow to separate of vital tumor tissue from necrosis and edema, improve delineation of tumor extension and improve detection of lesions localized in gray matter

  4. Hyperintense hepatocellular carcinoma on gadolinium-enhanced hepatic MRI

    International Nuclear Information System (INIS)

    Yoshikawa, Jun; Matsui, Osamu; Kadoya, Masumi; Gabata, Toshifumi; Arai, Kazunori; Takashima, Tsutomu

    1992-01-01

    We reported a phenomenon in which some hepatocellular carcinomas (HHCs) visualized as hypointense on plain T1 weighted MR images became hyperintense on gadolinium-DTPA (Gd-DTPA) (0.06∼0.23 mmol/kg) enhanced delayed images. Gd-DTPA enhanced images (using a super conducting magnet operating at 1.5T) of 44 HCCs were studied in comparison with contrast enhanced CT using 30∼80g of iodine. Six of 44 HCCs (14%) which were visualized as hypointense on plain T1 weighted image became hyperintense on delayed Gd-DTPA enhanced images. Although these were visualized as low intensity areas on both plain and enhanced CT, the contrast between HCC and the surrounding liver was small on post contrast CT. These findings were thought to be due to a stronger enhancement effect of Gd-DTPA than that of iodine. (author)

  5. Incidence of immediate adverse effects of gadolinium contrast media

    International Nuclear Information System (INIS)

    Ujita, Kouishi; Matsui, Satomi; Oikawa, Satoko; Habano, Youji; Ozaki, Daisuke; Ootake, Hidenori; Amanuma, Makoto; Endo, Keigo

    2010-01-01

    We investigated the adverse effects of intravenous injection of one of 4 types of gadolinium contrast media in 6550 patients: gadopentate dimeglumine (Gd-DTPA), 4299 patients; gadodiamide (Gd-DTPA-BMA), 1612; gadoteridol (Gd (HP-DO3A)), 565; and gadoterate meglumin (Gd-DOTA), 74. Thirty-two (0.49%) patients experienced adverse effects, which included rash (18.8%), nausea (40.6%), vomiting (34.4%), and an unpleasant sensation in the throat (6.3%). No patient required hospitalization. We compared the incidence of adverse effects from the 4 types of contrast media and found no difference in sex, age, body region examined, or method of contrast administration. Incidence was significantly higher for Gd (HP-DO3A) than Gd-DTPA and Gd-DTPA-BMA (P<0.000001). (author)

  6. Comparision between biphasic helical CT and dynamic gadolinium-enhanced MR in the detection and characterization of focal hepatic lesions in cirrhotic patients

    International Nuclear Information System (INIS)

    Puig, J.; Martin, J.; Donoso, L.; Falco, J.; Rue, M.

    1997-01-01

    To assess the agreement between biphasic helical computerized tomography (BHCT) and dynamic gadolinium-enhanced magnetic resonance (MR) in the detection and characterization of focal hepatic lesions in a group of cirrhotic patients. A prospective study was done in 50 cirrhotic patients suspected of having hepatocarcinoma (HC) on the basis of ultrasonographic images evaluated by means of BHCT and dynamic gadolinium-enhanced MR using fast low-angle shot (FLASH) sequences (110-135/4/90 degree centigree). The images were assessed jointly by four radiologists. Between the two techniques, a total of 83 lesions were detected. MR disclosed more lesions (n=79) than BHCT (n=67) (p<0.005). Moreover, 25 of the lesions that were visible by both techniques were more clearly evident in MR images (p<0.01). MR correctly classified 6 of 7 benign lesions (85%) and 49 of 66 malignant ones (74%). BHCT correctly classifed 2 of 7 benign lesions (28%) and 32 of 66 malignant ones (48%). The sensitivities of MR and BHCT for the characterization of these lesions were 74% and 48%, respectively (p=0.0009), while the respective specificities were 86% and 29% (P<0.001). Dynamic gadolinium-enhanced MR with FLASH sequences is more efficient than BHCT in the detection and characterization of focal lesions in cirrhotic patients. (Author) 37 refs

  7. The Effect of an EDTA-based Chelation Regimen on Patients with Diabetes and Prior Myocardial Infarction in TACT

    Science.gov (United States)

    Escolar, Esteban; Lamas, Gervasio A.; Mark, Daniel B.; Boineau, Robin; Goertz, Christine; Rosenberg, Yves; Nahin, Richard L.; Ouyang, Pamela; Rozema, Theodore; Magaziner, Allan; Nahas, Richard; Lewis, Eldrin F.; Lindblad, Lauren; Lee, Kerry L.

    2014-01-01

    Background The Trial to Assess Chelation Therapy (TACT) showed clinical benefit of an ethylene diamine tetraacetic acid (EDTA-based) infusion regimen in patients 50 years or older with prior myocardial infarction (MI). Diabetes prior to enrollment was a pre-specified subgroup. Methods and Results Patients received 40 infusions of EDTA chelation or placebo. 633 (37%) had diabetes (322 EDTA, 311 placebo). EDTA reduced the primary endpoint (death, reinfarction, stroke, coronary revascularization, or hospitalization for angina) [25% vs 38%, hazard ratio (HR) 0.59, 95% confidence interval (CI) (0.44, 0.79), p<0.001] over 5 years. The result remained significant after Bonferroni adjustment for multiple subgroups (99.4% CI (0.39, 0.88), adjusted p=0.002). All-cause mortality was reduced by EDTA chelation [10% vs 16%, HR 0.57, 95% CI (0.36, 0.88) p=0.011], as was the secondary endpoint (cardiovascular death, reinfarction, or stroke) [11% vs 17% HR 0.60, 95% CI (0.39, 0.91), p=0.017]. After adjusting for multiple subgroups, however, those results were no longer significant. The number needed to treat to reduce one primary endpoint was 6.5 over 5 years (95% CI (4.4, 12.7). There was no reduction in events in non-diabetics (n=1075, p=0.877), resulting in a treatment by diabetes interaction (p=0.004). Conclusions Post-MI diabetic patients age 50 or older demonstrated a marked reduction in cardiovascular events with EDTA chelation. These findings support efforts to replicate these findings and define the mechanisms of benefit. They do not, however, constitute sufficient evidence to indicate the routine use of chelation therapy for all post-MI diabetic patients. PMID:24254885

  8. A simplified suite of methods to evaluate chelator conjugation of antibodies: effects on hydrodynamic radius and biodistribution

    International Nuclear Information System (INIS)

    Al-Ejeh, Fares; Darby, Jocelyn M.; Thierry, Benjamin; Brown, Michael P.

    2009-01-01

    Introduction: Antibodies covalently conjugated with chelators such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) are required for radioimmunoscintigraphy and radioimmunotherapy, which are of growing importance in cancer medicine. Method: Here, we report a suite of simple methods that provide a preclinical assessment package for evaluating the effects of DOTA conjugation on the in vitro and in vivo performance of monoclonal antibodies. We exemplify the use of these methods by investigating the effects of DOTA conjugation on the biochemical properties of the DAB4 clone of the La/SSB-specific murine monoclonal autoantibody, APOMAB (registered) , which is a novel malignant cell death ligand. Results: We have developed a 96-well microtiter-plate assay to measure directly the concentration of DOTA and other chelators in antibody-chelator conjugate solutions. Coupled with a commercial assay for measuring protein concentration, the dual microtiter-plate method can rapidly determine chelator/antibody ratios in the same plate. The biochemical properties of DAB4 immunoconjugates were altered as the DOTA/Ab ratio increased so that: (i) mass/charge ratio decreased; (ii) hydrodynamic radius increased; (iii) antibody immunoactivity decreased; (iv) rate of chelation of metal ions and specific radioactivity both increased and in vivo, (v) tumor uptake decreased as nonspecific uptake by liver and spleen increased. Conclusion: This simplified suite of methods readily identifies biochemical characteristics of the DOTA-immunoconjugates such as hydrodynamic diameter and decreased mass/charge ratio associated with compromised immunotargeting efficiency and, thus, may prove useful for optimizing conjugation procedures in order to maximize immunoconjugate-mediated radioimmunoscintigraphy and radioimmunotherapy.

  9. Non-invasive vascular imaging: assessing tumour vascularity

    International Nuclear Information System (INIS)

    Delorme, S.; Knopp, M.V.

    1998-01-01

    Non-invasive assessment of vascularity is a new diagnostic approach to characterise tumours. Vascular assessment is based on the pathophysiology of tumour angiogenesis and its diagnostic implications for tumour biology, prognosis and therapy response. Two current techniques investigating vascular features in addition to morphology are Doppler ultrasonography and contrast-enhanced MRI. Diagnostic differentiation has been shown to be possible with Doppler, and a high degree of observed vascularity could be linked to an aggressive course of the disease. Dynamic MRI using gadolinium chelates is already used clinically to detect and differentiate tumours. The histological correlation shows that capillary permeability is increased in malignant tumours and is the best criterion for differentiation from benign processes. Permeability and perfusion factors seem to be more diagnostic than overall vessel density. New clinical applications are currently being established for therapy monitoring. Further instrumental developments will bring harmonic imaging in Doppler, and faster imaging techniques, higher spatial resolution and novel pharmacokinetic concepts in MRI. Upcoming contrast agents for both Doppler and MRI will further improve estimation of intratumoural blood volume and vascular permeability. (orig.)

  10. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    International Nuclear Information System (INIS)

    Hunt, F.C.; Maddalena, D.J.

    1982-01-01

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

  11. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, F.C.; Maddalena, D.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights)

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo.

  12. Chelator induced phytoextraction and in situ soil washing of Cu

    International Nuclear Information System (INIS)

    Kos, Bostjan; Lestan, Domen

    2004-01-01

    In a soil column experiment, we investigated the effect of 5 mmol kg -1 soil addition of citric acid, ethylenediamine tetraacetate (EDTA), diethylenetriamine-pentaacetate (DTPA) and [S,S]-stereoisomer of ethylenediamine-disuccinate (EDDS) on phytoextraction of Cu from a vineyard soil with 162.6 mg kg -1 Cu, into the test plant Brassica rapa var. pekinensis. We also examined the use of a horizontal permeable barrier, composed of layers of nutrient enriched sawdust and apatite, for reduction of chelator induced Cu leaching. The addition of all chelators, except citric acid, enhanced Cu mobility and caused leaching of 19.5-23% of initial total Cu from the soil column. However, Cu plant uptake did not increase accordingly; the most effective was the EDDS treatment, in which plant Cu concentration reached 37.8±1.3 mg kg -1 Cu and increased by 3.3-times over the control treatment. The addition of none of the chelators in the concentration range from 5 to 15 mmol kg -1 exerted any toxic effect on respiratory soil microorganisms. When EDDS was applied into the columns with horizontal permeable barriers, only 0.53±0.32% of the initial total Cu was leached. Cu (36.7%) was washed from the 18 cm soil layer above the barrier and accumulated in the barrier. Our results indicate that rather than for a reduction of Cu leaching during rather ineffective chelate induced Cu phytoextraction, horizontal permeable barriers could be more effective in a new remediation technique of controlled in situ soil washing of Cu with biodegradable chelates

  13. Copper chelators: chemical properties and bio-medical applications.

    Science.gov (United States)

    Tegoni, M; Valensin, D; Toso, L; Remelli, M

    2014-01-01

    Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined.

  14. Synthesis and characterization of Gadolinium-Lectin conjugates as selective blood-vessel contrast agents for magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Pashkunova-Martic, I.

    2004-11-01

    Molecular imaging without use of ionizing radiation has recently been developed for both magnetic resonance and ultrasound imaging (MRI, US) and is expected to play a major future role in diagnosis and monitoring of tumours. In MRI, targeted nanoparticle contrast media (CM) with high relaxivities are required in order to obtain adequate signal-to-noise ratios, due to the low number of target sites. The size, charge and chemical constitution of the targeted nanoparticle CM are expected to influence nanoparticle interactions with cells and tissue elements significantly, and hence the targeting, the accumulation and dwell time at the targeted site, and the type and rate of clearance of the nanoparticles. The work reported here aims to characterise and optimise these parameters in mouse and human models, using nanoparticles targeted to a major carbohydrate determinant of the endothelial cell surface which is present in all blood vessels. Specific binding to the endothelium was demonstrated in both living and chemically fixed human vessels and in mice. Long-standing spin-echo and FLASH-3D images were obtained in the vasculature of living mice, in strong contrast to the rapid renal clearance of gadolinium-DTPA chelates which are widely used in the clinic. Nanoparticle size was found to be a major determinant of the biological response, and our data indicate that an optimal nanoparticle size lies between 50-100 nm diameter. We expect that hyperpermeable vessels present in tumours will permit targeting of optimised nanoparticles to the tumour cells, permitting MRI monitoring of the tumour. (author)

  15. ICP-oa TOFMS utilisation to determine the Gd isotopic abundance in gadolinium nitrate

    International Nuclear Information System (INIS)

    Dragomir, M.; Ohai, D.; Dumitrescu, I.; Furtuna, I.

    2010-01-01

    This paper is describes the development of a method that should permit the determination of isotope abundance of gadolinium in gadolinium nitrate, used as burnable poison at Cernavoda NPP. To determine the isotopic abundance of gadolinium the inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer (ICP-oa TOFMS) was used. The ICP-oa TOFMS allows the elimination of noise associated with instrumental drift and instability (flicker noise). The absence of flicker noise in the ICP-oa TOFMS means that the isotope ratios can be measured up to the statistical limit of ion counting. With TOFMS, each spectrum acquired represents signals from ions extracted from the plasma during the same time interval, formed from identical plasma and sample introduction events. Therefore, the ICP-oa TOFMS, Optimass 8000, has been successfully used for isotope ratio measurements of Gd in gadolinium nitrate [Gd (NO 3 ) 3 x 6H 2 O] sample solutions. (authors)

  16. Reaction of ammonium triphosphate with gadolinium nitrate in aqueous solution at 273K

    International Nuclear Information System (INIS)

    Rodicheva, G.V.; Tananaev, I.V.; Romanova, N.M.

    1982-01-01

    The solubility in the system (NW 4 ) 5 P 3 O 10 -Gd(NO 3 ) 3 - H 2 O (273 K) is studied. Depending on the reagent ratio formation of the compounds Gd 5 (P 3 O 10 ) 3 x22H 2 O, NH 4 Gd 3 (P 3 O 10 ) 2 x12H 2 O and (NH 4 ) 3 Gd 4 (P 3 O 10 ) 3 x14H 2 O is established. Gadolinium triphosphates, separated from solution, are studied using the methods of paper chromatography, X-ray diffractometry, thermography. Simultaneously with thermal dehydration of gadolinium triphosphates the processes of triphosphate decomposition and phosphate anion condensation take place. A mixture of crystalline ortho-phosphate and long- chain polyphosphate of gadolinium is the final product of thermal decomposition (1063 K) of normal and doubl e ammonium- containing gadolinium triphosphates [ru

  17. Standard test methods for analysis of sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the analysis of sintered gadolinium oxide-uranium dioxide pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Section Carbon (Total) by Direct CombustionThermal Conductivity Method C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Chlorine and Fluorine by Pyrohydrolysis Ion-Selective Electrode Method C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Gadolinia Content by Energy-Dispersive X-Ray Spectrometry C1456 Test Method for Determination of Uranium or Gadolinium, or Both, in Gadolinium Oxide-Uranium Oxide Pellets or by X-Ray Fluorescence (XRF) Hydrogen by Inert Gas Fusion C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction Isotopic Uranium Composition by Multiple-Filament Surface-Ioni...

  18. Luminescence study on Eu or Tb doped lanthanum-gadolinium pyrosilicate crystal

    Czech Academy of Sciences Publication Activity Database

    Kurosawa, S.; Shishido, T.; Sugawara, T.; Nomura, A.; Yubuta, K.; Pejchal, Jan; Murakami, R.; Yokota, Y.; Shoji, Y.; Ohashi, Y.; Kamada, K.; Yoshikawa, A.

    2015-01-01

    Roč. 41, Mar (2015), s. 80-83 ISSN 0925-3467 Institutional support: RVO:68378271 Keywords : scintillator * gadolinium pyrosilicate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2015

  19. Impact of Impaired Renal Function on Gadolinium Retention After Administration of Gadolinium-Based Contrast Agents in a Mouse Model.

    Science.gov (United States)

    Kartamihardja, A Adhipatria P; Nakajima, Takahito; Kameo, Satomi; Koyama, Hiroshi; Tsushima, Yoshito

    2016-10-01

    The aim of this study was to investigate the impact of impaired renal function on gadolinium (Gd) retention in various organs after Gd-based contrast agent injection. After local animal care and review committee approval, 23 normal mice and 26 with renal failure were divided into 4 treatment groups (Gd-DTPA-BMA, 5 mmol/kg; Gd-DOTA, 5 mmol/kg; GdCl3, 0.02 mmol/kg; and saline, 250 μL). Each agent was intravenously administered on weekdays for 4 weeks. Samples were collected on days 3 (short-term) and 45 (long-term) after the last injection. Gadolinium concentrations were quantified by inductively coupled plasma-mass spectrometry. Three mice with renal failure and 2 normal mice in the GdCl3 group and 1 mouse with renal failure in the Gd-DTPA-BMA group died. In the Gd-DTPA-BMA group, impaired renal function increased short-term Gd retention in the liver, bone, spleen, skin, and kidney (P DTPA-BMA showed higher Gd retention than Gd-DOTA. Although Gd retention in the Gd-DOTA group was generally low, impaired renal function increased only long-term hepatic Gd retention. Hepatic and splenic Gd retentions were significantly higher than other organs' Gd retention in the GdCl3 group (P DTPA-BMA administration, long-term Gd retention for Gd-based contrast agents was almost unaffected by renal function, suggesting that the chemical structures of retained Gd may not be consistent and some Gd is slowly eliminated after initially being retained.

  20. Effectiveness of late gadolinium enhancement to improve outcomes prediction in patients referred for cardiovascular magnetic resonance after echocardiography

    Science.gov (United States)

    2013-01-01

    Background Echocardiography (echo) is a first line test to assess cardiac structure and function. It is not known if cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) ordered during routine clinical practice in selected patients can add additional prognostic information after routine echo. We assessed whether CMR improves outcomes prediction after contemporaneous echo, which may have implications for efforts to optimize processes of care, assess effectiveness, and allocate limited health care resources. Methods and results We prospectively enrolled 1044 consecutive patients referred for CMR. There were 38 deaths and 3 cardiac transplants over a median follow-up of 1.0 years (IQR 0.4-1.5). We first reproduced previous survival curve strata (presence of LGE and ejection fraction (EF) echocardiography, CMR with LGE further improves risk stratification of individuals at risk for death or death/cardiac transplant. PMID:23324403

  1. Visualization of isolated trigeminal nerve invasion by lymphoma using gadolinium-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Manon-Espaillat, R.; Lanska, D.J.; Ruff, R.L.; Cleveland Veteran's Administration Medical Center, OH; Case Western Reserve Univ., Cleveland, OH; Masaryk, T.; University Hospitals of Cleveland, OH; Case Western Reserve Univ., Cleveland, OH

    1990-01-01

    A 50-year-old man with active histiocytic lymphoma for 12 years developed an isolated right trigeminal neuropathy. Initial evaluation with head computed tomography, X-rays of the skull base, bone scan, and cerebrospinal fluid analysis including cytology were normal. Gadolinium-enhanced magnetic resonance imaging (MRI) showed enlargement of the proximal third of the right trigeminal nerve. Gadolinium-enhanced MRI can be useful for the early demonstration of cranial nerve invasion by lymphoma. (orig.)

  2. Theoretical study of hyperfine fields due to S-P and transition impurities in gadolinium matrix

    International Nuclear Information System (INIS)

    Santos Leal, C.E. dos.

    1985-01-01

    This work presents a systematic theoretical study for the hyperfine field due to diluted s-p-and transition impurities in metallic gadolinium matrices. The peculiarities de a gadolinium matrix are shown, they are characterized by a semi-completed 4f-shell, which is far from (below) the energetic levels such as the type s-p and d-conduction bands. (author)

  3. Gadolinium Use in Spine Pain Management Procedures for Patients with Contrast Allergies: Results in 527 Procedures

    International Nuclear Information System (INIS)

    Safriel, Yair; Ang, Roberto; Ali, Muhammed

    2008-01-01

    Introduction. To review the safety and efficacy of gadolinium in spine pain management procedures in patients at high risk for a contrast reaction and who are not suitable candidates for the use of standard non-ionic contrast. Methods. We reviewed records over a 61-month period of all image-guided spinal pain management procedures where patients had allergies making them unsuitable candidates for standard non-ionic contrast and where gadolinium was used to confirm needle tip placement prior to injection of medication. Results. Three hundred and four outpatients underwent 527 procedures. A spinal needle was used in all but 41 procedures. Gadolinium was visualized using portable C-arm fluoroscopy in vivo allowing for confirmation of needle tip location. The gadolinium dose ranged from 0.2 to 10 ml per level. The highest dose received by one patient was 15.83 ml intradiscally during a three-level discogram. Three hundred and one patients were discharged without complication or known delayed complications. One patient had documented intrathecal injection but without sequelae and 2 patients who underwent cervical procedures experienced seizures requiring admission to the intensive care unit. Both the latter patients were discharged without any further complications. Conclusion. Based on our experience we recommend using gadolinium judiciously for needle tip confirmation. We feel more confident using gadolinium in the lumbar spine and in cervical nerve blocks. Gadolinium should probably not be used as an injectate volume expander. The indications for gadolinium use in cervical needle-guided spine procedures are less clear and use of a blunt-tipped needle should be considered

  4. Scoring of late gadolinium enhancement in cardiac magnetic resonance imaging can predict cardiac events in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Nojiri, Ayumi; Hongo, Kenichi; Kawai, Makoto; Komukai, Kimiaki; Sakuma, Toru; Taniguchi, Ikuo; Yoshimura, Michihiro

    2011-01-01

    Late gadolinium enhancement (LGE) of cardiac magnetic resonance imaging (MRI) represents myocardial fibrosis and may be related to the clinical outcome of various heart diseases. This study evaluated the relationship between LGE and cardiac events in hypertrophic cardiomyopathy (HCM) using a new scoring method. This study retrospectively followed 46 HCM patients without heart failure symptoms for 3.8±1.8 years. Gadolinium-enhanced cardiac MRI was performed in all patients. Cardiac events including newly developed heart failure or ventricular tachyarrhythmia were evaluated during the follow-up period. We evaluated the predictive factors to identify the patients with cardiac events. None of the risk factors reported to be related to poor outcome or the existence of LGE alone could predict cardiac events, which might be due to the small number of subjects investigated in this study. A new scoring method for LGE-positive areas (LGE score) was applied and higher LGE score can predict cardiac events in this study population. The proposed LGE score for cardiac MRI is considered to be a potentially valid method for assessing cardiac events in HCM patients. (author)

  5. Effect of gadolinium on hepatic fat quantification using multi-echo reconstruction technique with T2* correction and estimation

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Mingmei; Wu, Bing; Liu, Zhiqin; Song, Hai; Meng, Xiangfeng; Wu, Xinhuai [The Military General Hospital of Beijing PLA, Department of Radiology, Beijing (China); Zhang, Jing [The 309th Hospital of Chinese People' s Liberation Army, Department of Radiology, Beijing (China)

    2016-06-15

    To determine whether hepatic fat quantification is affected by administration of gadolinium using a multiecho reconstruction technique with T2* correction and estimation. Forty-eight patients underwent the investigational sequence for hepatic fat quantification at 3.0T MRI once before and twice after administration of gadopentetate dimeglumine (0.1 mmol/kg). A one-way repeated-measures analysis of variance with pairwise comparisons was conducted to evaluate the systematic bias of fat fraction (FF) and R2* measurements between three acquisitions. Bland-Altman plots were used to assess the agreements between pre- and post-contrast FF measurements in the liver. A P value <0.05 indicated statistically significant difference. FF measurements of liver, spleen and spine revealed no significant systematic bias between the three measurements (P > 0.05 for all). Good agreements (95 % confidence interval) of FF measurements were demonstrated between pre-contrast and post-contrast1 (-0.49 %, 0.52 %) and post-contrast2 (-0.83 %, 0.77 %). R2* increased in liver and spleen (P = 0.039, P = 0.01) after administration of gadolinium. Although under the impact of an increased R2* in liver and spleen post-contrast, the investigational sequence can still obtain stable fat quantification. Therefore, it could be applied post-contrast to substantially increase the efficiency of MR examination and also provide a backup for the occasional failure of FF measurements pre-contrast. (orig.)

  6. Effect of gadolinium on hepatic fat quantification using multi-echo reconstruction technique with T2* correction and estimation

    International Nuclear Information System (INIS)

    Ge, Mingmei; Wu, Bing; Liu, Zhiqin; Song, Hai; Meng, Xiangfeng; Wu, Xinhuai; Zhang, Jing

    2016-01-01

    To determine whether hepatic fat quantification is affected by administration of gadolinium using a multiecho reconstruction technique with T2* correction and estimation. Forty-eight patients underwent the investigational sequence for hepatic fat quantification at 3.0T MRI once before and twice after administration of gadopentetate dimeglumine (0.1 mmol/kg). A one-way repeated-measures analysis of variance with pairwise comparisons was conducted to evaluate the systematic bias of fat fraction (FF) and R2* measurements between three acquisitions. Bland-Altman plots were used to assess the agreements between pre- and post-contrast FF measurements in the liver. A P value <0.05 indicated statistically significant difference. FF measurements of liver, spleen and spine revealed no significant systematic bias between the three measurements (P > 0.05 for all). Good agreements (95 % confidence interval) of FF measurements were demonstrated between pre-contrast and post-contrast1 (-0.49 %, 0.52 %) and post-contrast2 (-0.83 %, 0.77 %). R2* increased in liver and spleen (P = 0.039, P = 0.01) after administration of gadolinium. Although under the impact of an increased R2* in liver and spleen post-contrast, the investigational sequence can still obtain stable fat quantification. Therefore, it could be applied post-contrast to substantially increase the efficiency of MR examination and also provide a backup for the occasional failure of FF measurements pre-contrast. (orig.)

  7. Femoral head vascularisation in Legg-Calve-Perthes disease: comparison of dynamic gadolinium-enhanced subtraction MRI with bone scintigraphy

    International Nuclear Information System (INIS)

    Lamer, Sylvie; Dorgeret, Sophie; Brillet, Pierre-Yves; Hassan, Max; Sebag, Guy H.; Khairouni, Abdeslam; Mazda, Keyvan; Bacheville, Eric; Pennecot, Georges F.; Bloch, Juliette

    2002-01-01

    Heading AbstractBackground. It has been reported that MRI using a dynamic gadolinium-enhanced subtraction technique can allow the early identification of ischaemia and the pattern of revascularisation in Legg-Calve-Perthes (LCP) disease with increased spatial and contrast resolution. Therefore, dynamic gadolinium-enhanced subtraction (DGS) MRI may be a possible non-ionising substitute for bone scintigraphy.Objective. The purpose of this prospective study was to compare DGS MRI and bone scintigraphy in the assessment of femoral head perfusion in LCP disease.Materials and methods. Twenty-six DGS MR images and bone scintigraphies of 25 hips in 23 children were obtained at different stages of LCP disease; three stage I, 12 stage II, six stage III and five stage IV (Waldenstroem classification). The extent of necrosis, epiphyseal revascularisation pathways (lateral pillar, medial pillar, and/or transphyseal perfusion) and metaphyseal changes were analysed.Results. Total agreement between both techniques was noted in the depiction of epiphyseal necrosis (kappa=1), and metaphyseal abnormalities (kappa=0.9). DGS MRI demonstrated better revascularisation in the lateral (kappa=0.62) and medial pillars (kappa=0.52). The presence of basal transphyseal reperfusion was more conspicuous with MRI.Conclusions. DGS MRI allows early detection of epiphyseal ischaemia and accurate analysis of the different revascularisation patterns. These changes are directly related to the prognosis of LCP disease and can aid therapeutic decision making. (orig.)

  8. Polyaminoquinoline iron chelators for vectorization of antiproliferative agents: design, synthesis, and validation.

    Science.gov (United States)

    Corcé, Vincent; Morin, Emmanuelle; Guihéneuf, Solène; Renault, Eric; Renaud, Stéphanie; Cannie, Isabelle; Tripier, Raphaël; Lima, Luís M P; Julienne, Karine; Gouin, Sébastien G; Loréal, Olivier; Deniaud, David; Gaboriau, François

    2012-09-19

    Iron chelation in tumoral cells has been reported as potentially useful during antitumoral treatment. Our aim was to develop new polyaminoquinoline iron chelators targeting tumoral cells. For this purpose, we designed, synthesized, and evaluated the biological activity of a new generation of iron chelators, which we named Quilamines, based on an 8-hydroxyquinoline (8-HQ) scaffold linked to linear polyamine vectors. These were designed to target tumor cells expressing an overactive polyamine transport system (PTS). A set of Quilamines bearing variable polyamine chains was designed and assessed for their ability to interact with iron. Quilamines were also screened for their cytostatic/cytotoxic effects and their selective uptake by the PTS in the CHO cell line. Our results show that both the 8-HQ moiety and the polyamine part participate in the iron coordination. HQ1-44, the most promising Quilamine identified, presents a homospermidine moiety and was shown to be highly taken up by the PTS and to display an efficient antiproliferative activity that occurred in the micromolar range. In addition, cytotoxicity was only observed at concentrations higher than 100 μM. We also demonstrated the high complexation capacity of HQ1-44 with iron while much weaker complexes were formed with other cations, indicative of a high selectivity. We applied the density functional theory to study the binding energy and the electronic structure of prototypical iron(III)-Quilamine complexes. On the basis of these calculations, Quilamine HQ1-44 is a strong tridentate ligand for iron(III) especially in the form of a 1:2 complex.

  9. Effects of synthetic Zn chelates on flax response and soil Zn status

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, D.; Almendros, P.; Alvarez, J.M.

    2016-11-01

    Throughout the world, flax (Linum usitatissimum L.) is often grown in Zn-deficient soils, but appropriate fertilizer management can optimize both crop yield and micronutrient content. A greenhouse experiment was conducted on Typic Haploxeralf (pH 6.1) and Typic Calcixerept (pH 8.1) soils to study the relative efficiency of chelated Zn using two application rates of three different Zn sources [Zn-EDDHSA, ethylenediamine-di-(2-hydroxy-5-sulfophenylacetate of Zn); Zn-HEDTA, N-2-hydroxyethyl-ethylenediaminetriacetate of Zn; and Zn-EDTA, ethylenediaminetetraacetate of Zn]. Dry matter /DM) yield, Zn concentration, chlorophyll content, crude fiber and tensile properties were monitored and the soil-Zn status (available-Zn, Zn-fractions and total-Zn) was assessed. Zinc chelate applications increased the most labile forms of Zn in soils and Zn concentrations in plants. The low rate of Zn generally had a beneficial effect on DM yield and tensile properties. The exception was Zn-EDTA in the weakly acidic soil, where the highest Zn concentrations were observed in leaves and whole shoots; this coincided with the largest concentrations of labile Zn in soil. The most efficient fertilizers were Zn-EDDHSA (in both soils) and Zn-EDTA (in the calcareous soil). The relatively large amounts of labile and available Zn present in both of the soils fertilized with Zn-EDTA points to the applying this chelate at lower rate than 5 mg Zn/kg; this should, in turn, reduce the cost of Zn fertilization and minimize environmental pollution risk. (Author)

  10. Water-soluble chelating polymers for removal of actinides from wastewater

    International Nuclear Information System (INIS)

    Jarvinen, G.D.

    1997-01-01

    Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent

  11. Water-soluble chelating polymers for removal of actinides from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, G.D. [Los Alamos National Lab., NM (United States)

    1997-10-01

    Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent.

  12. Experimental determination of electron shock excitation cross sections for a singly charged gadolinium ion

    International Nuclear Information System (INIS)

    Smirnov, Yu.M.

    1995-01-01

    The trends observed in the processes of excitation with simultaneous ionization have received little study. This is particularly so for rare-earth elements having electron shells of complex structure and optical spectra very rich in lines. Among the basic factors responsible for such a situation, we should mention two: the difficulty presented by theoretical analysis of the processes discussed and the absence of factual information about the excitation cross sections with simultaneous ionization for the majority of rare-earth elements. The aim of the present work is to investigate the excitation of a singly charged gadolinium ion in the collisions of monokinetic electrons with gadolinium atoms. Up to the present time, only the excitation cross sections of a gadolinium atom have been measured, where investigation of the electron shock excitation of gadolinium atoms in their free state is associated with overcoming large experimental difficulties. About 160 crosss sections for the excitation of a singly charged gadolinium ion were measured and for a third of the cross sections; the energy dependences were recorded for the change in energy of the elecrons from the excitation threshold up to 200 eV. Included are tables of the wavelength, transistion, internal quantum number, the energy of the lowere and upper levels, and the values of cross sections for the charged gadolinium ion. Diagrams of the transistion energy states of Gd (II) and spectroscopy are presented and explained

  13. Fumonisin B1 hepatotoxicity in mice is attenuated by depletion of Kupffer cells by gadolinium chloride

    International Nuclear Information System (INIS)

    He, Quanren; Kim, Jiyoung; Sharma, Raghubir P.

    2005-01-01

    Fumonisin B 1 (FB 1 ) is a toxic and carcinogenic mycotoxin produced by Fusarium verticillioides found on corn worldwide. The biological effects of FB 1 are attributed to sphingolipid metabolism disruption as a result of ceramide synthase inhibition. Tumor necrosis factor α (TNFα) is an important modulator of FB 1 hepatotoxicity. Kupffer cells are major source of cytokine production in liver. In the present study we investigated the effects of Kupffer cell depletion by gadolinium on FB 1 hepatotoxicity in female BALB/c mice. Mice were given saline or 50 mg/kg of gadolinium chloride once via the tail vein; 16 h later they were treated with subcutaneous injections of vehicle or 2.25 mg/kg/day FB 1 in saline for three successive days. Gadolinium significantly attenuated FB 1 -induced increases in the activities of circulating alanine aminotransferase and aspartate aminotransferase and reduced the FB 1 -induced hepatocyte apoptosis and free sphinganine accumulation in liver. Both gadolinium and FB 1 treatments individually increased the expression of selected cell signal factors; e.g., TNFα, TNF receptor 1, TNF-related apoptosis-inducing ligand, lymphotoxin β, interferon γ, and transforming growth factor β1; gadolinium chloride did not alter FB 1 -induced expression of the above genes. Results indicated that Kupffer cells play a role in FB 1 hepatotoxicity. Decreased FB 1 -induced sphinganine accumulation and increased protective TNFα signaling by gadolinium chloride may in part account for its ameliorating effect on FB 1 liver damage

  14. Gadolinium-containing contrast media for radiographic examinations: a position paper

    International Nuclear Information System (INIS)

    Thomsen, Henrik S.; Almen, Torsten; Morcos, Sameh K.

    2002-01-01

    Recently, it has been suggested that gadolinium-based contrast media could be used for radiological examinations in patients with significant renal impairment, previous severe generalized reaction to iodinated contrast media or thyroid disease about to undergo radioactive iodine treatment; however, the indications for and risks of using gadolinium agents in this way are not well known; hence, the Contrast Media Safety Committee of The European Society of Urogenital Radiology reviewed the literature to issue a position paper on this subject. A comprehensive literature review was performed and the resulting report was discussed at the Ninth European Symposium on Urogenital Radiology in Genoa, Italy, June 2002. Review of the literature indicates that according to experimental data on animals gadolinium-based contrast media have more nephrotoxic potential than iodinated contrast media in equivalent X-ray attenuating doses; therefore, gadolinium-based contrast media should not replace iodinated contrast media in patients with renal insufficiency for radiographic examinations. For patients with previous severe generalized reactions to iodinated contrast media, and in patients about to undergo thyroid treatment with radioactive iodine gadolinium-based contrast media in approved intravenous doses, up to 0.3 mmol/kg body weight will not give diagnostic radiographic information in most cases. Gadolinium-based contrast media are not approved for radiographic examinations. (orig.)

  15. Optimization of gadolinium burnable poison loading by the conjugate gradients method

    International Nuclear Information System (INIS)

    Drumm, C.R.

    1984-01-01

    Improved use of burnable poison is suggested for pressurized water reactors (PWR's) to insure a sufficiently negative moderator temperature coefficient of reactivity for extended burnup cycles and low leakage refueling patterns. The use of gadolinium as a burnable poison can lead to large axial fluctuations in the power distribution through the cycle. The goal of this work is to determine the optimal axial distribution of gadolinium burnable poison in a PWR to overcome the axial fluctuations, yielding an improved power distribution. The conjugate gradients optimization method is used in this work because of the high degree of nonlinearity of the problem. The neutron diffusion and depletion equations are solved for a one-dimensional one-group core model. The state variables are the flux, the critical soluble boron concentration, and the burnup. The control variables are the number of gadolinium pins per assembly and the beginning-of-cycle gadolinium concentration, which determine the gadolinium cross section. Two separate objectives are considered: 1) to minimize the power peaking factor, which will minimize the capital cost of the plant; and 2) to maximize the cycle length, which will minimize the fuel cost for the plant. It is shown in this work that optimizing the gadolinium distribution can yield an improved power distribution

  16. Experimental lead intoxication in dogs: a comparison of blood lead and urinary delta-aminolevulinic acid following intoxication and chelation therapy.

    Science.gov (United States)

    Green, R A; Selby, L A; Zumwalt, R W

    1978-01-01

    Intravenous lead administration to dogs produced an acute syndrome of lead intoxication charcterized by depression, vomiting, anorexia and weight loss. The effect of chelation therapy with calcium disodium ethylene diamine tetraacetate, penicillamine or both was determined by serially monitoring changes in blood lead and urine delta-aminolevulinic acid. Following therapy, blood lead values were significantly lower in chelated dogs than non-treated lead exposed dogs on days 7 and 10. Urine delta-aminolevulinic acid at day 7 was significantly higher in untreated lead exposed dogs than in other groups. There was no significant difference in blood lead or urine delta-aminolevulinic acid between lead intoxicated dogs which underwent the indicated chelation therapy protocols. There was, however, a trend for higher urinary delta-aminolevulinic acid excretion in those intoxicated dogs undergoing calcium disodium ethylene diamine tetraacetate therapy as opposed to those undergoing penicilamine therapy. There was no significant correlation between blood lead and urinary delta-aminolevulinic acid previous to lead exposure. However, after lead exposure significant correlation was present at days 4, 7, 10 and 14. Certain lead exposed dogs following chelation therapy were noted to have normal blood lead levels but elevated urinary delta-aminolevulinic acid suggesting that blood lead does not always correlate with metabolic effects of lead in the body. Urinary delta-aminolevulinic acid was therefore recommended as an additional laboratory parameter which improved assessment of lead exposure in dogs, particularly in determining adequacy of chelation therapy. PMID:667707

  17. Liver acquisition with acceleration volume acquisition gadolinium-enhanced magnetic resonance combined with T2 sequences in the diagnosis of local recurrence of rectal cancer.

    Science.gov (United States)

    Cao, Wuteng; Li, Fangqian; Gong, Jiaying; Liu, Dechao; Deng, Yanhong; Kang, Liang; Zhou, Zhiyang

    2016-11-22

    To investigate the efficacy of liver acquisition with acceleration volume acquisition (LAVA) gadolinium-enhanced magnetic resonance (MR) sequences and to assess its added accuracy in diagnosing local recurrence (LR) of rectal cancer with conventional T2-weighted fast spin echo (FSE) sequences. Pelvic MRI, including T2-weighted FSE sequences, gadolinium-enhanced sequences of LAVA and T1-weighted FSE with fat suppression, was performed on 225 patients with postoperative rectal cancer. Two readers evaluated the presence of LR according to "T2" (T2 sequences only), "T2 + LAVA-Gad" (LAVA and T2 imaging), and "T2 + T1-fs-Gad" (T1 fat suppression-enhanced sequence with T2 images). To evaluate diagnostic efficiency, imaging quality with LAVA and T1-fs-Gad by subjective scores and the signal intensity (SI) ratio. In the result, the SI ratio of LAVA was significantly higher than that of T1-fs-Gad (p = 0.0001). The diagnostic efficiency of "T2 + LAVA-Gad" was better than that of "T2 + T1-fs-Gad" (p = 0.0016 for Reader 1, p = 0.0001 for Reader 2) and T2 imaging only (p = 0.0001 for Reader 1; p = 0.0001 for Reader 2). Therefore, LAVA gadolinium-enhanced MR increases the accuracy of diagnosis of LR from rectal cancer and could replace conventional T1 gadolinium-enhanced sequences in the postoperative pelvic follow-up of rectal cancer.

  18. Contrast-enhanced NMR imaging: animal studies using gadolinium-DTPA complex

    International Nuclear Information System (INIS)

    Brasch, R.C.; Weinmann, H.J.; Wesbey, G.E.

    1984-01-01

    Gadolinium (Gd)-DTPA complex was assessed as a nuclear magnetic resonance (NMR) contrast-enhancing agent by experimentally imaging normal and diseased animals. After intravenous injection, Gd-DTPA, a strongly paramagnetic complex by virtue of unpaired electrons, was rapidly excreted into the urine of rats, producing an easily observable contrast enhancement on NMR images in kidney parenchyma and urine. Sterile soft-tissue abscesses demonstrated an obvious rim pattern of enhancement. A focus of radiation-induced brain damage in a canine model was only faintly detectable on spin-echo NMR images before contrast administration; after 0.5 mmol/kg Gd-DTPA administration, the lesion intensity increased from 3867 to 5590. In comparison, the normal brain with an intact blood-brain barrier remained unchanged in NMR characterization. Gd-DTPA is a promising new NMR contrast enhancer for the clinical assessment of renal function, of inflammatory lesions, and of focal disruption of the blood-brain barrier

  19. Removal of cadmium from fish sauce using chelate resin.

    Science.gov (United States)

    Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

    2015-04-15

    Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Treatment of some radioactive wastes by using new chelating membranes

    International Nuclear Information System (INIS)

    Hegazy, S.A.; El-Adham, K.; Abdel Geleel, M.; Soliman, S.A.

    2000-01-01

    The preparation of chelating membranes containing nitrile and carboxylic acid as functional groups was investigated. The modification of such membranes by chemical treatments to produce significant changes in their properties was studied. This modification results in a higher rate of exchange and higher capacity. The applicability of such modified membranes in the removal of Co-60 and Cs-137 from their wastes were tested. The dependence of these radioactive nuclides uptake on the time and degree of grafting for H CI-, NH 2 OH-and KOH-treated membranes was investigated. It was found that the adsorption rate and capacity were higher for KOH-treated membrane than those for the NH 2 OH and H CI treated ones. The prepared grafted membranes have a good affinity towards the adsorption or chelation with Co-60 and Cs-137. This result may make such prepared materials acceptable for practicable use in some radioactive waste treatments and recovery

  1. Chelation studies involving decontamination of light lanthanides by polyaminopolycarboxylic

    International Nuclear Information System (INIS)

    Hassan, N.E.H.

    1985-01-01

    The present thesis constitutes chelation studies involving decontamination of light lanthanides, cobalt , and uranium with 2,2-bis-acryloyliminomethylene- acid (BAETA) using the spectrophotometric method. the work carried out aimed to clear up the effectiveness of BAETA as a decontaminating agent for radioactive nuclides from human body . the thesis includes a general introduction , outlines the aim of work and contains three main chapters . the results of the work are discussed at the end of the thesis. the first chapter deals with a comprehensive survey of the relevant literature. this includes the metabolism and toxicity of cerium, uranium, cobalt and Ln +3 elements, general methodologies of internal decontamination, choice and effectiveness of chelating agents

  2. Iron overload and chelation therapy in myelodysplastic syndromes.

    Science.gov (United States)

    Temraz, Sally; Santini, Valeria; Musallam, Khaled; Taher, Ali

    2014-07-01

    Iron overload remains a concern in MDS patients especially those requiring recurrent blood transfusions. The consequence of iron overload may be more relevant in patients with low and intermediate-1 risk MDS who may survive long enough to experience such manifestations. It is a matter of debate whether this overload has time to yield organ damage, but it is quite evident that cellular damage and DNA genotoxic effect are induced. Iron overload may play a critical role in exacerbating pre-existing morbidity or even unmask silent ones. Under these circumstances, iron chelation therapy could play an integral role in the management of these patients. This review entails an in depth analysis of iron overload in MDS patients; its pathophysiology, effect on survival, associated risks and diagnostic options. It also discusses management options in relation to chelation therapy used in MDS patients and the impact it has on survival, hematologic response and organ function. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles

    DEFF Research Database (Denmark)

    Hervella, Pablo; Ortiz, Elisa Parra; Needham, David

    2016-01-01

    ) Chelate copper into the octaethyl porphyrin; (3) Encapsulate OEP-Cu in nanoparticles: the encapsulation efficiency of copper into liquid nanoparticles (LNP), solid nanoparticles (SNP) and phospholipid liposomes (PL) was evaluated by UV-Vis and atomic absorption spectroscopy; (4) Retain the encapsulated...... OEP-Cu in the liquid or solid cores of the nanoparticles in the presence of a lipid sink. RESULTS: (1) The size of the nanoparticles was found to be strongly dependent on the Reynolds number and the initial concentration of components for the fast injection technique. At high Reynolds number (2181......), a minimum value for the particle diameter of ∼30nm was measured. (2) Copper was chelated by OEP in a 1:1mol ratio with an association constant of 2.57×10(5)M(-1). (3) The diameter of the nanoparticles was not significantly affected by the presence of OEP or OEP-Cu. The percentage of encapsulation of copper...

  4. Iron chelates: a challenge to chemists and Moessbauer spectroscopists

    Energy Technology Data Exchange (ETDEWEB)

    Homonnay, Z., E-mail: homonnay@chem.elte.hu; Szilagyi, P. A.; Vertes, A. [Eoetvoes Lorand University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary); Kuzmann, E. [Hungarian Academy of Sciences, Department of Nuclear Chemistry, Chemical Research Center (Hungary); Sharma, V. K. [Florida Institute of Technology (United States); Molnar, G.; Bousseksou, A. [CNRS UPR-8241, Laboratoire de Chimie de Coordination (France); Greneche, J.-M. [Universite du Maine, Laboratoire de Physique de l' Etat Condense, CNRS UMR 6087 (France); Brausam, A.; Meier, R.; Eldik, R. van [University of Erlangen-Nuernberg, Institute for Inorganic Chemistry (Germany)

    2008-02-15

    The speciation of iron in aqueous solutions containing Fe{sup 3+} and selected chelates such as EDTA, EDDA, CDTA and HEDTA has been studied using transmission {sup 57}Fe Moessbauer spectrometry in frozen solutions. The protonation of various complexes as well as binuclear complex formation could be detected as a function of pH. Autoreduction of Fe{sup 3+} to Fe{sup 2+} was observed in several cases. Reaction with hydrogen peroxide proved to be rather different for the four ligands, while the dihapto complex [XFe({eta}{sup 2}-O{sub 2})]{sup 3-} had surprisingly identical Moessbauer parameters for X = EDTA, CDTA or HEDTA. Paramagnetic spin relaxation observed in the Moessbauer spectra was found to be strongly influenced by the identity of the chelating ligand, despite the basically spin-spin origin of the phenomenon.

  5. Self-assembled polymeric chelate nanoparticles as potential theranostic agents

    Czech Academy of Sciences Publication Activity Database

    Škodová, Michaela; Černoch, Peter; Štěpánek, Petr; Chánová, Eliška; Kučka, Jan; Kálalová, Zuzana; Kaňková, Dana; Hrubý, Martin

    2012-01-01

    Roč. 13, č. 18 (2012), s. 4244-4250 ISSN 1439-4235 R&D Projects: GA ČR GPP207/10/P054; GA ČR GA202/09/2078; GA ČR GAP304/12/0950 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : chelate s * nanoparticles * polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.349, year: 2012

  6. Decontamination of process equipment using recyclable chelating solvent

    Energy Technology Data Exchange (ETDEWEB)

    Jevec, J.; Lenore, C.; Ulbricht, S. [Babcock & Wilcox, Co., R& DD, Alliance, OH (United States)

    1995-10-01

    The Department of Energy (DOE) is now faced with the task of meeting decontamination and decommissioning obligations at numerous facilities by the year 2019. Due to the tremendous volume of material involved, innovative decontamination technologies are being sought that can reduce the volumes of contaminated waste materials and secondary wastes requiring disposal. This report describes the results of the performance testing of chelates and solvents for the dissolution of uranium.

  7. Polymeric metal chelates with piperazine(bis)dithiocarbamate

    International Nuclear Information System (INIS)

    Larionov, S.V.; Kosareva, L.A.; Ikorskij, V.N.; Uskov, E.M.

    1982-01-01

    Roentgenoamorphous polymer chelates of Fe 3 , Co 2 , Ni 2 , Cu 2 , Zn 2 , Cd 2 , Pb 2 with tetradentate bridge ligand piperazine-(bis) dithiocarbamate have been synthesized. IR spectra in the region 200-400 cm - 1 point to coordination of sulphur atoms of groups CS 2- with metals. It is found that among the polymers synthesized CuLxH 2 O possesses the lowest electric resistance

  8. Flue gas desulfurization/denitrification using metal-chelate additives

    Science.gov (United States)

    Harkness, J.B.L.; Doctor, R.D.; Wingender, R.J.

    1985-08-05

    A method of simultaneously removing SO/sub 2/ and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO/sub 2/ and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled. 3 figs.

  9. Preferred hydride growth orientations on oxide-coated gadolinium surfaces

    International Nuclear Information System (INIS)

    Benamar, G.M.; Schweke, D.; Kimmel, G.; Mintz, M.H.

    2012-01-01

    Highlights: ► The preferred hydride growth orientations on gadolinium metal coated by a thin oxide layer are presented. ► A preferred growth of the (1 0 0) h plane of the face centered cubic (FCC) GdH 2 is observed for the hydride spots forming below the oxidation layer. ► A change to the (1 1 1) h plane of the cubic hydride dominates for the hydride's Growth Centers. ► The texture change is attributed to the surface normal compressive stress component exerted by the oxidation layer on the developing hydride. - Abstract: The initial development of hydrides on polycrystalline gadolinium (Gd), as on some other hydride forming metals, is characterized by two sequential steps. The first step involves the rapid formation of a dense pattern of small hydride spots (referred to as the “small family” of hydrides) below the native oxidation layer. The second stage takes place when some of the “small family” nucleants (referred to as “growth centers”, GCs) break the oxide layer, leading to their rapid growth and finally to the massive hydriding of the sample. In the present study, the texture of the two hydride families was studied, by combining X-ray diffraction (XRD) analysis with a microscopic analysis of the hydride, using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It has been observed that for the “small family”, a preferred growth of the (1 0 0) h plane of the cubic GdH 2 takes place, whereas for the GCs, a change to the (1 1 1) h plane of the cubic hydride dominates. These preferred growth orientations were analyzed by their structure relation with the (0 0 .1) m basal plane of the Gd metal. It has been concluded that the above texture change is due to the surface normal compressive stress component exerted by the oxidation overlayer on the developing hydride, preventing the (0 0 .1) m ||(1 1 1) h growth orientation. This stress is relieved upon the rupture of that overlayer and the development of the GCs, leading to

  10. Can aquatic macrophytes be biofilters for gadolinium based contrasting agents?

    Science.gov (United States)

    Braun, Mihály; Zavanyi, Györgyi; Laczovics, Attila; Berényi, Ervin; Szabó, Sándor

    2018-05-15

    The use of gadolinium-based contrasting agents (GBCA) is increasing because of the intensive usage of these agents in magnetic resonance imaging (MRI). Waste-water treatment does not reduce anthropogenic Gd-concentration significantly. Anomalous Gd-concentration in surface waters have been reported worldwide. However, removal of GBCA-s by aquatic macrophytes has still hardly been investigated. Four aquatic plant species (Lemna gibba, Ceratophyllum demersum, Elodea nuttallii, E. canadensis) were investigated as potential biological filters for removal of commonly used but structurally different GBCA-s (Omniscan, Dotarem) from water. These plant species are known to accumulate heavy metals and are used for removing pollutants in constructed wetlands. The Gd uptake and release of the plants was examined under laboratory conditions. Concentration-dependent infiltration of Gd into the body of the macrophytes was measured, however significant bioaccumulation was not observed. The tissue concentration of Gd reached its maximum value between day one and four in L. gibba and C. demersum, respectively, and its volume was significantly higher in C. demersum than in L. gibba. In C. demersum, the open-chain ligand Omniscan causes two-times higher tissue Gd concentration than the macrocyclic ligand Dotarem. Gadolinium was released from Gd-treated duckweeds into the water as they were grown further in Gd-free nutrient solution. Tissue Gd concentration dropped by 50% in duckweed treated by Omniscan and by Dotarem within 1.9 and 2.9 days respectively. None of the macrophytes had a significant impact on the Gd concentration of water in low and medium concentration levels (1-256 μg L -1 ). Biofiltration of GBCA-s by common macrophytes could not be detected in our experiments. Therefore it seems that in constructed wetlands, aquatic plants are not able to reduce the concentration of GBCA-s in the water. Furthermore there is a low risk that these plants cause the

  11. Mercury removal in utility wet scrubber using a chelating agent

    Science.gov (United States)

    Amrhein, Gerald T.

    2001-01-01

    A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

  12. Effectiveness of chelation therapy with time after acute uranium intoxication

    International Nuclear Information System (INIS)

    Domingo, J.L.; Ortega, A.; Llobet, J.M.; Corbella, J.

    1990-01-01

    The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy

  13. Hydroxyurea could be a good clinically relevant iron chelator.

    Science.gov (United States)

    Italia, Khushnooma; Colah, Roshan; Ghosh, Kanjaksha

    2013-01-01

    Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

  14. Chelate forms of biometalls. Theoretical aspects of obtaining and characteristics

    Directory of Open Access Journals (Sweden)

    A. Kapustyan

    2017-04-01

    Full Text Available The problem of microelements bioavailability is highlighted and the correct ways of its solution are substantiated as a result of generalization of theoretical aspects of obtaining of the biometals chelate forms. The characteristics of the main biogenic elements, their physiological significance, electrochemical properties are presented. The main examples of the participation of biometals in various biological processes are given. The properties and the structure peculiarities of biometals coordination complexes are considered in detail. It is shown that in obtaining of biometals chelate forms, there is the mutual selectivity and the affinity of biometals and ligands. The main factors of obtaining a hard metal complex are given. Potential bioligands for obtaining bioavailable forms of microelements are detailed. Among them there are amino acids, peptides, proteins, nucleic acids, carbohydrates. The possible character of complexation depending on the nature of the bioligand is indicated. Practical examples of preparation of biometals mixed ligand complexes are given. The expediency of using metabolic products and processing of lactic acid bacteria as promising components of mixed ligand chelate complexes is substantiated. These substances contain in their composition a mass of potential donor atoms that are capable to form covalent and coordination bonds with biomethalles, and also possess high biological and immunotropic activities. The use of this system in the biocoordination compounds of the "metals of life" can provide a synergistic effect of the components, significantly to expand the range of their physiological activity and to increase the degree of assimilation by the body.

  15. High precision isotopic ratio analysis of volatile metal chelates

    International Nuclear Information System (INIS)

    Hachey, D.L.; Blais, J.C.; Klein, P.D.

    1980-01-01

    High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

  16. Hydroxyurea could be a good clinically relevant iron chelator.

    Directory of Open Access Journals (Sweden)

    Khushnooma Italia

    Full Text Available Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

  17. Copper and Zinc Chelation as a Treatment of Alzheimer's Disease

    Science.gov (United States)

    Hodak, Miroslav; Bernholc, Jerry

    2014-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. The cause of the disease remains unknown, but amyloid- β (A β), a short peptide, is considered causal its pathogenesis. At cellular level, AD is characterized by deposits mainly composed of A β that also contain elevated levels of transition metals ions. Targeting metals is a promising new strategy for AD treatment, which uses moderately strong metal chelators to sequester them from A β or the environment. PBT2 is a chelating compound that has been the most promising in clinical trials. In our work, we use computer simulations to investigate complexes of a close analog of PBT2 with Cu2+ and Zn2+ ions. The calculations employ KS/FD DFT method, which combines Kohn-Sham DFT with the frozen-density DFT to achieve efficient description of explicit solvent beyond the first solvation shell. Our work is based on recent experiments and examines both 1:1 and 2:1 chelator-metal stochiometries detected experimentally. The results show that copper attaches more strongly than zinc, find that 1:1 complexes involve water in the first coordination shell and determine which one of several possible 2:1 geometries is the most preferable.

  18. f-Element Ion Chelation in Highly Basic Media

    International Nuclear Information System (INIS)

    Paine, Robert T.

    1999-01-01

    High-level radioactive waste (HLW) generated in the DOE complex is stored in tanks at several sites, but predominantly it is found at the Hanford reservation. Much of the material has been exposed to high pHs, consequently the waste exists in a complex, poorly understood mixture of solids, gels and solutions. The final waste remediation plan may involve chemical separation of fractions and a suitable, well developed molecular chemistry basis for performing these separations is not available. Indeed, the fundamental chemical behavior of most radioactive nuclides in basic media is not known. The goal of this project is to undertake fundamental studies of the coordination chemistry of f-element species in basic aqueous solutions containing common waste treatment ions (e.g., NO3 -, CO3 2-, organic carboxylates, and EDTA), as well as new waste scrubbing chelators produced in this study. The experimental agenda includes: 1. Studies of the speciation of Sr and Ln ions in basic solutions wit h and without common counterions; 2. Preparations of new multifunctional ligands that may act as strong, ion-specific chelators for Sr and/or Ln ions in basic media; and 3. Studies of the coordination and dissolution behavior of oxide-hydroxide species, as well as in insoluble sols, gels, and precipitates in combination with new chelating ligands. It is anticipated that this coordination chemistry will facilitate the design of advanced separation schemes required for handling the complex waste matrices found at the Hanford HLW facility

  19. Early-enhancing non-neoplastic lesions on gadolinium-enhanced MRI of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Kanematsu, M. E-mail: masa-gif@umin.ac.jp; Kondo, H.; Semelka, R.C.; Matsuo, M.; Goshima, S.; Hoshi, H.; Moriyama, N.; Itai, Y

    2003-10-01

    AIM: To assess the frequency, cause, and significance of early-enhancing, non-neoplastic (EN) lesions on gadolinium-enhanced magnetic resonance imaging (MRI) of the liver performed for the detection of malignant hepatic tumours. MATERIALS AND METHODS: From September 1997 to September 2000, we reviewed the images of 125 patients, suspected of having hepatic tumours, in whom (1) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) imaging in addition to unenhanced T1- and T2-weighted MRI was performed, (2) conventional angiography and combination computed tomography (CT) hepatic arteriography and CT during arterial portography were performed within 2 weeks of the MRI, and (3) definitive surgery within 2 weeks of the MRI or follow-up study by means of intravenously contrast-enhanced CT or MRI in 10 months or more was performed. Angiographic studies were correlated to determine the underlying causes of the EN lesions. RESULTS: We found 78 EN lesions in 36 patients (29%), ranging in size from 4 and 50 mm (mean, 12.2 mm). From the MR reports, our radiologists had prospectively diagnosed EN lesions as probable malignant tumours in eight (10%), possible malignant tumours in 36 (46%), and probable non-neoplastic lesion in 34 (44%). EN lesions were found in 27 of 81 (33%) cirrhotic patients and in nine of 44 (20%) non-cirrhotic patients. Fifty-one EN lesions (65%) were located along the liver edge. The shape was circular in 42 (54%), oval in 14 (18%), irregular in 12 (15%), wedge-shaped in seven (9%), and fan-shaped in three (4%). Twenty EN lesions (26%) appeared slightly hyperintense on T2-weighted images. The causes were non-neoplastic arterio-portal shunting in 48 (62%), cystic venous drainage in four (5%), rib compression in four (5%), aberrant right gastric venous drainage in two (3%), and unknown in 20 (26%). CONCLUSION: Over half the number of EN lesions were caused by non-neoplastic arterio-portal shunting, occasionally showing slight hyperintensity on

  20. Structure-activity relationships of novel salicylaldehyde isonicotinoyl hydrazone (SIH analogs: iron chelation, anti-oxidant and cytotoxic properties.

    Directory of Open Access Journals (Sweden)

    Eliška Potůčková

    Full Text Available Salicylaldehyde isonicotinoyl hydrazone (SIH is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability. Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O, which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.

  1. Tissue gadolinium deposition in renally impaired rats exposed to different gadolinium-based MRI contrast agents: evaluation with inductively coupled plasma mass spectrometry (ICP-MS).

    Science.gov (United States)

    Sato, Tomohiro; Ito, Katsuyoshi; Tamada, Tsutomu; Kanki, Akihiko; Watanabe, Shigeru; Nishimura, Hirotake; Tanimoto, Daigo; Higashi, Hiroki; Yamamoto, Akira

    2013-10-01

    To quantify tissue gadolinium (Gd) deposition in renally impaired rats exposed to Gd-EOB-DTPA and other Gd-based MRI contrast agents by means of inductively coupled plasma mass spectrometry (ICP-MS), and to compare the differences in distribution among major organs as possible triggers for nephrogenic systemic fibrosis (NSF). A total of 15 renally impaired rats were injected with Gd-EOB-DTPA, Gd-DTPA-BMA and Gd-HP-DO3A. Gd contents of skin, liver, kidney, lung, heart, spleen, diaphragm and femoral muscle were measured by inductively coupled plasma mass spectrometry (ICP-MS). Histological assessment was also conducted. Tissue Gd deposition in all organs was significantly higher (P=0.005~0.009) in the Gd-DTPA-BMA group than in the Gd-HP-DO3A and Gd-EOB-DTPA groups. In the Gd-DTPA-BMA group, Gd was predominantly deposited in kidney (1306±605.7μg/g), followed by skin, liver, lung, spleen, femoral muscle, diaphragm and heart. Comparing Gd-HP-DO3A and Gd-EOB-DTPA groups, Gd depositions in the kidney, liver and lung were significantly lower (P=0.009~0.011) in the Gd-EOB-DTPA group than in the Gd-HP-DO3A group although no significant differences were seen for any other organs. Gd-EOB-DTPA is a stable and safe Gd-based contrast agent (GBCA) showing lower Gd deposition in major organs in renally impaired rats, compared with other GBCAs. This fact suggests that the risk of NSF onset would be low in the use of Gd-EOB-DTPA. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) of Cadaveric Shoulders: Comparison of Contrast Dynamics in Hyaline and Fibrous Cartilage after Intraarticular Gadolinium Injection

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, E. (Dept. of Radiology, Charite Universitaetsmedizin Berlin (Germany)); Hodler, J.; Pfirrmann, C.W.A. (Dept. of Radiology, Orthopedic Univ. Hospital Balgrist, Zuerich (Switzerland))

    2009-01-15

    Background: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. Purpose: To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Material and Methods: Transverse T1 maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T1 maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. Results: T1 of unenhanced hyaline cartilage of the glenoid was 568+-34 ms. T1 of unenhanced fibrous cartilage of the labrum was 552+-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T1(Gd) values in fibrous cartilage. T1 and ?R1 values of hyaline and fibrous cartilage after 2.5 hours were 351+-16 ms and 1.1+-0.09/s, and 332+-31 ms and 1.2+-0.1/s, respectively. Conclusion: A significant decrease in T1(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium

  3. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of cadaveric shoulders: comparison of contrast dynamics in hyaline and fibrous cartilage after intraarticular gadolinium injection.

    Science.gov (United States)

    Wiener, E; Hodler, J; Pfirrmann, C W A

    2009-01-01

    Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Transverse T(1) maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T(1) maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. T(1) of unenhanced hyaline cartilage of the glenoid was 568+/-34 ms. T(1) of unenhanced fibrous cartilage of the labrum was 552+/-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T(1)(Gd) values in fibrous cartilage. T(1) and triangle Delta R(1) values of hyaline and fibrous cartilage after 2.5 hours were 351+/-16 ms and 1.1+/-0.09 s(-1), and 332+/-31 ms and 1.2+/-0.1 s(-1), respectively. A significant decrease in T(1)(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium.

  4. Heavy Metals, Cardiovascular Disease, and the Unexpected Benefits of Chelation Therapy.

    Science.gov (United States)

    Lamas, Gervasio A; Navas-Acien, Ana; Mark, Daniel B; Lee, Kerry L

    2016-05-24

    This review summarizes evidence from 2 lines of research previously thought to be unrelated: the unexpectedly positive results of TACT (Trial to Assess Chelation Therapy), and a body of epidemiological data showing that accumulation of biologically active metals, such as lead and cadmium, is an important risk factor for cardiovascular disease. Considering these 2 areas of work together may lead to the identification of new, modifiable risk factors for atherosclerotic cardiovascular disease. We examine the history of chelation up through the report of TACT. We then describe work connecting higher metal levels in the body with the future risk of cardiovascular disease. We conclude by presenting a brief overview of a newly planned National Institutes of Health trial, TACT2, in which we will attempt to replicate the findings of TACT and to establish that removal of toxic metal stores from the body is a plausible mechanistic explanation for the benefits of edetate disodium treatment. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  5. Stainless-Steel-Gadolinium Alloys; Alliages Acier Inoxydable-Gadolinium; Splavy iz nerzhaveyushchej stali i gadoliniya; Aleaciones de Acero Inoxidable-Gadolinio

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, M.; Kato, H. [Albany Metallurgy Research Center, Bureau Of Mines, United States Department of the Interior, Albany, OR (United States)

    1964-06-15

    Because of the excellent corrosion resistance of stainless steels and the interest in gadolinium as a poison material, alloys of the two compounds were studied.Gadolinium was alloyed with AISE 304-type and chromium-type stainless steels; and then phase relationships, fabricability and properties were studied. The melting points of minor phases in alloys containing low percentages of gadolinium were noted to have a large effect on the structures resulting from equilibrating treatments and fabricability of the steels. When gadolinium was alloyed with the chromium-nickel-type steel, two minor phases, Fe{sub 9}Gd and Ni{sub 7}Gd, were observed to melt at 1080 Degree-Sign C, which limited the heat treatment and fabrication temperatures. Alloys with up to 5 wt.% gadolinium were successfully fabricated, and mechanical and corrosion properties were determined. No changes in the mechanical properties or resistance to hot-water corrosion of the steel were observed on alloying with up to about 3 wt.% gadolinium. Because of fabrication temperature limitations placed on chromium-nickel steels by the melting point of the minor phases, the effects of gadolinium on chromium steels were studied. Only one minor phase that melted at 1320 Degree-Sign C was noted on investigation of the 10 wt. % gadolinium isopleth in the chromium-iron-gadolinium alloy system. This property would enable one to equilibrate and fabricate these gadolinium steels at normally used temperatures. (author) [French] Les auteurs ont etudie des alliages d'acier inoxydable et de gadolinium en raison de l'excellente resistance a la corrosion des aciers inoxydables et de l 'interet que presente le gadolinium comme poison. Ils ont allie du gadolinium a des aciers inoxydables AISI de nuance 304 et des aciers au chrome et ils ont etudie le diagramme des phases, les possibilites de transformation et les proprietes de ces alliages. Dans les alliages d'une faible teneur en gadolinium, les points de fusion des phases

  6. Reverse microemulsion synthesis of layered gadolinium hydroxide nanoparticles

    Science.gov (United States)

    Xu, Yadong; Suthar, Jugal; Egbu, Raphael; Weston, Andrew J.; Fogg, Andrew M.; Williams, Gareth R.

    2018-02-01

    A reverse microemulsion approach has been explored for the synthesis of layered gadolinium hydroxide (LGdH) nanoparticles in this work. This method uses oleylamine as a multifunctional agent, acting as surfactant, oil phase and base. 1-butanol is additionally used as a co-surfactant. A systematic study of the key reaction parameters was undertaken, including the volume ratio of surfactant (oleylamine) to water, the reaction time, synthesis temperature, and the amount of co-surfactant (1-butanol) added. It proved possible to obtain pristine LGdH materials at temperatures of 120 °C or below with an oleylamine: water ratio of 1:4. Using larger amounts of surfactant or higher temperatures caused the formation of Gd(OH)3, either as the sole product or as a major impurity phase. The LGdH particles produced have sizes of ca. 200 nm, with this size being largely independent of temperature or reaction time. Adjusting the amount of 1-butanol co-surfactant added permits the size to be varied between 200 and 300 nm.

  7. Electron magnetic resonance of gadolinium-doped calcium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Biasi, R.S. de, E-mail: rsbiasi@ime.eb.br [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil); Grillo, M.L.N., E-mail: mluciag@uerj.br [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

    2012-06-15

    Electron magnetic resonance (EMR) spectra of gadolinium-doped calcium fluoride have been studied at room temperature for Gd concentrations between 0.01 and 2.00 mol%. Gd{sup 3+} ions in sites with two different symmetries were observed. One of the sites, with cubic symmetry, is unstable at room temperature and decays with a time constant of 2.2 day{sup -1}. The other site, with tetragonal symmetry, is stable and is attributed to Gd{sup 3+} ions in substitutional sites next to a charge-compensating F{sup -} interstitial ion. The linewidth and intensity of the EMR spectrum with tetragonal symmetry increase with increasing Gd concentration. A theoretical calculation based on the concentration dependence of the EMR linewidth yields an effective range of the exchange interaction between Gd{sup 3+} ions in CaF{sub 2} of 0.774 nm, of the same order as that of Gd{sup 3+} ions in other cubic ionic compounds.

  8. Extracellular gadolinium-based contrast media: Differences in diagnostic efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Molen, Aart J. van der [Department of Radiology C-2S, Leiden University Medical Centre, Albinusdreef 2, NL-2333 ZA Leiden (Netherlands)], E-mail: molen@lumc.nl; Bellin, Marie-France [Universite Paris-Sud XI, AP-HP, Service de Radiologie, Hopital Paul Brousse, 12-14 Avenue Paul Vaillant Couturier, F-94804 Villejuif Cedex (France)

    2008-05-15

    Since the introduction of the first gadolinium-based contrast agent (Gd-CA) in 1988 it has become clear that these agents significantly improve the diagnostic efficacy of MRI. Studies on single agents have shown that, in comparison to unenhanced sequences, all agents help to improve the detection and delineation of lesions which can alter diagnosis in up to 40% of patients. Doubling or tripling the standard dose of 0.1 mmol/kg body weight may be beneficial for selected indications (e.g. brain perfusion, equivocal single dose study in MRI for brain metastasis, small vessel MR angiography). A more limited number of studies have compared the various agents. These studies do not show clinically significant differences in diagnostic efficacy between the various extracellular Gd-CA. Agents with higher concentration or protein binding may be relatively better suitable for selected applications (e.g. perfusion MRI). The higher relaxivity agents may be used in somewhat lower doses than the extracellular agents.

  9. Extracellular gadolinium-based contrast media: Differences in diagnostic efficacy

    International Nuclear Information System (INIS)

    Molen, Aart J. van der; Bellin, Marie-France

    2008-01-01

    Since the introduction of the first gadolinium-based contrast agent (Gd-CA) in 1988 it has become clear that these agents significantly improve the diagnostic efficacy of MRI. Studies on single agents have shown that, in comparison to unenhanced sequences, all agents help to improve the detection and delineation of lesions which can alter diagnosis in up to 40% of patients. Doubling or tripling the standard dose of 0.1 mmol/kg body weight may be beneficial for selected indications (e.g. brain perfusion, equivocal single dose study in MRI for brain metastasis, small vessel MR angiography). A more limited number of studies have compared the various agents. These studies do not show clinically significant differences in diagnostic efficacy between the various extracellular Gd-CA. Agents with higher concentration or protein binding may be relatively better suitable for selected applications (e.g. perfusion MRI). The higher relaxivity agents may be used in somewhat lower doses than the extracellular agents

  10. Gadolinium neutron capture therapy for brain tumors. Biological aspects

    International Nuclear Information System (INIS)

    Takagaki, Masao; Oda, Yoshifumi; Matsumoto, Masato; Kikuchi, Haruhiko; Kobayashi, Tooru; Kanda, Keiji; Ujeno, Yowri.

    1994-01-01

    This study investigated the tumoricidal effect of gadolinium neutron capture therapy (Gd-NCT) in in vitro and in vivo systems using Gd-DTPA. In in vitro study, a certain amount of Gd-DTPA, yielding 5000 ppm Gd-n, was added to human glioma cells, T98G, upon which thermal neutrons were exposed. After irradiation, the cells were incubated and the colonies were counted 10 days later. In in vivo study, Fisher-344 rats with experimentally induced gliosarcoma cells (9L) were exposed to thermal neutrons at a fluence rate of 3E+9/s for 1 h immediately after iv injection of Gd-DTPA. Two weeks after irradiation, brain samples were histologically examined. Tumor clearance of Gd-DTPA was also determined. In vitro analysis showed that a 1% survival level was obtained at 3.75E+12 (n/cm 2 ) for the Gd (+) medium and 2.50E+13 (n/cm 2 ) for the Gd (-) medium. In in vivo analysis, the concentration of Gd in 9L-rat brain tumor after iv injection of 0.2 mg/kg Gd-DTPA was found to be less than 100 ppm, but Gd-NCT on 9L-rat brain tumor administered with a ten-fold dose showed a substantial killing effect on tumor without serious injury to the normal brain structure. The killing effect of Gd-NCT was confirmed in in vitro and in vivo systems. (N.K.)

  11. MCNP analysis of the nine-cell LWR gadolinium benchmark

    International Nuclear Information System (INIS)

    Arkuszewski, J.J.

    1988-01-01

    The Monte Carlo results for a 9-cell fragment of the light water reactor square lattice with a central gadolinium-loaded pin are presented. The calculations are performed with the code MCNP-3A and the ENDF-B/5 library and compared with the results obtained from the BOXER code system and the JEF-1 library. The objective of this exercise is to study the feasibility of BOXER for the analysis of a Gd-loaded LWR lattice in the broader framework of GAP International Benchmark Analysis. A comparison of results indicates that, apart from unavoidable discrepancies originating from different data evaluations, the BOXER code overestimates the multiplication factor by 1.4 % and underestimates the power release in a Gd cell by 4.66 %. It is hoped that further similar studies with use of the JEF-1 library for both BOXER and MCNP will help to isolate and explain these discrepancies in a cleaner way. (author) 4 refs., 9 figs., 10 tabs

  12. Structure and properties of gadolinium loaded calcium phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cuiling [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Liang, Xiaofeng, E-mail: XFLiang@swust.edu.cn [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Li, Haijian; Yu, Huijun; Li, Zhen [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Yang, Shiyuan [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

    2014-10-15

    The glass samples with composition xGd{sub 2}O{sub 3}–(50 − x)CaO–50P{sub 2}O{sub 5} (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd{sub 2}O{sub 3} containing is up to 6 mol%. Two main crystalline phases, Ca{sub 2}P{sub 2}O{sub 7} and Gd{sub 3}(P{sub 2}O{sub 7}){sub 3}, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q{sup 2}) units and the depolymerization of phosphate network with the addition of Gd{sub 2}O{sub 3}. Both the chemical durability and the glass transition temperature (T{sub g}) are improved with the increase of Gd{sub 2}O{sub 3}, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass.

  13. Structure and properties of gadolinium loaded calcium phosphate glasses

    International Nuclear Information System (INIS)

    Wang, Cuiling; Liang, Xiaofeng; Li, Haijian; Yu, Huijun; Li, Zhen; Yang, Shiyuan

    2014-01-01

    The glass samples with composition xGd 2 O 3 –(50 − x)CaO–50P 2 O 5 (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd 2 O 3 containing is up to 6 mol%. Two main crystalline phases, Ca 2 P 2 O 7 and Gd 3 (P 2 O 7 ) 3 , are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q 2 ) units and the depolymerization of phosphate network with the addition of Gd 2 O 3 . Both the chemical durability and the glass transition temperature (T g ) are improved with the increase of Gd 2 O 3 , which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass

  14. Immunomodulation by gadolinium chloride-induced Kupffer cell phagocytosis blockade

    International Nuclear Information System (INIS)

    Lazar, G.; Husztik, E.; Kiss, I.; Szakacs, J.; Olah, J.

    1998-01-01

    Gadolinium chloride (GdCl 3 ), a rare earth metal salt, depresses macrophage activity, and is commonly used to study the physiology of the reticuloendothelial system. In the present work, the effect of GdCl 3 -induced Kupffer cell blockade on the humoral immune response in mice to sheep red blood cells (SRBC) was investigated. Kupffer cell phagocytosis blockade was found to increase both the primary and secondary immune responses to SRBC. The primary immune response was significantly augmented in animals injected intravenously with GdCl 3 2, 3 or 4 days before injection of the cellular antigen, but GdCl 3 injected 7 days before the antigen did not modify the immune response. Increased secondary humoral immune responses were also observed. When GdCl 3 was injected 2 days before the second dose of antigen, the numbers of both IgM and IgG-producing plaque forming cells were augmented. GdCl 3 injected 2 days before the first dose of SRBC did not modify the humoral immune response. Earlier studies with 51 Cr-labelled foreign red blood cells suggested that the augmentation of the humoral immune response in GdCl 3 -pretreated mice is a consequence of the spillover of the antigen from the liver into the spleen and other extrahepatic reticuloendothelial organs. (orig.)

  15. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    Science.gov (United States)

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  16. A pyrophosphate-responsive gadolinium(III) MRI contrast agent.

    Science.gov (United States)

    Surman, Andrew J; Bonnet, Célia S; Lowe, Mark P; Kenny, Gavin D; Bell, Jimmy D; Tóth, Eva; Vilar, Ramon

    2011-01-03

    This study shows that the relaxivity and optical properties of functionalised lanthanide-DTPA-bis-amide complexes (lanthanide=Gd(3+) and Eu(3+) , DTPA=diethylene triamine pentaacetic acid) can be successfully modulated by addition of specific anions, without direct Ln(3+) /anion coordination. Zinc(II)-dipicolylamine moieties, which are known to bind strongly to phosphates, were introduced in the amide "arms" of these ligands, and the interaction of the resulting Gd-Zn(2) complexes with a range of anions was screened by using indicator displacement assays (IDAs). Considerable selectivity for polyphosphorylated species (such as pyrophosphate and adenosine-5'-triphosphate (ATP)) over a range of other anions (including monophosphorylated anions) was apparent. In addition, we show that pyrophosphate modulates the relaxivity of the gadolinium(III) complex, this modulation being sufficiently large to be observed in imaging experiments. To establish the binding mode of the pyrophosphate and gain insight into the origin of the relaxometric modulation, a series of studies including UV/Vis and emission spectroscopy, luminescence lifetime measurements in H(2) O and D(2) O, (17) O and (31) P NMR spectroscopy and nuclear magnetic resonance dispersion (NMRD) studies were carried out. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Gadolinium-DTPA enhancement of symptomatic nerve roots in MRI of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Tyrrell, P.N.M.; Cassar-Pullicino, V.N.; McCall, I.W. [Department of Diagnostic Imaging, The Institute of Orthopaedics, The Robert Jones and Agnes Hunt Orthopaedic and District Hospital NHS Trust, Oswestry, Shropshire SY10 7AG (United Kingdom)

    1998-02-01

    Disc prolapse presenting with sciatica may be associated with enhancement of the symptomatic nerve root following magnetic resonance imaging (MRI) with intravenous gadolinium (Gd)-DTPA. Previous studies have shown, however, that this does not occur in all cases. The aim of this study was to assess the incidence of nerve root enhancement in patients with sciatica and disc prolapse and to try to identify any specific features that might be associated with the phenomenon. A total of 227 patients presenting with low back pain and/or sciatica underwent a MRI study of the lumbar spine with intravenous contrast enhancement. Nineteen of 81 (23.5 %) patients with disc prolapse demonstrated nerve root enhancement. Nerve root enhancement had a highly significant association with sequestrated disc lesions (13/19, 68 %; P < 0.0005), and was primarily seen in the symptomatic ipsilateral nerve root (16/19, 84 %). The sensitivity of nerve root enhancement associated with disc prolapse was 23.5 % with a specificity of 95.9 %, a positive predictive value of 76 % and a negative predictive value of 69.3 %. Nerve root enhancement may be indicative of the symptomatic level but its poor sensitivity negates the routine use of Gd-DTPA in MRI for sciatica. (orig.) With 4 figs., 1 tab., 37 refs.

  18. Gadolinium-DTPA enhancement of symptomatic nerve roots in MRI of the lumbar spine

    International Nuclear Information System (INIS)

    Tyrrell, P.N.M.; Cassar-Pullicino, V.N.; McCall, I.W.

    1998-01-01

    Disc prolapse presenting with sciatica may be associated with enhancement of the symptomatic nerve root following magnetic resonance imaging (MRI) with intravenous gadolinium (Gd)-DTPA. Previous studies have shown, however, that this does not occur in all cases. The aim of this study was to assess the incidence of nerve root enhancement in patients with sciatica and disc prolapse and to try to identify any specific features that might be associated with the phenomenon. A total of 227 patients presenting with low back pain and/or sciatica underwent a MRI study of the lumbar spine with intravenous contrast enhancement. Nineteen of 81 (23.5 %) patients with disc prolapse demonstrated nerve root enhancement. Nerve root enhancement had a highly significant association with sequestrated disc lesions (13/19, 68 %; P < 0.0005), and was primarily seen in the symptomatic ipsilateral nerve root (16/19, 84 %). The sensitivity of nerve root enhancement associated with disc prolapse was 23.5 % with a specificity of 95.9 %, a positive predictive value of 76 % and a negative predictive value of 69.3 %. Nerve root enhancement may be indicative of the symptomatic level but its poor sensitivity negates the routine use of Gd-DTPA in MRI for sciatica. (orig.)

  19. Gadolinium-enhanced dynamic magnetic resonance imaging with endorectal coil for local staging of rectal cancer

    International Nuclear Information System (INIS)

    Tamakawa, Mitsuharu; Kawaai, Yuriko; Shirase, Ryuji

    2010-01-01

    The aim of this study was to evaluate the accuracy of dynamic gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) with endorectal coil for assessing tumor invasion based on simple classification criteria. A total of 58 patients with operable primary rectal cancer underwent preoperative MRI. An enhancement pattern in Gd-enhanced dynamic MRI with regard to tumor penetration was clarified. Retrospectively, two observers independently scored T2-weighted MRI and T2-weighted MRI combined with Gd-enhanced dynamic MRI for tumor penetration using the following criteria: With Gd-enhanced dynamic MRI, T1 tumors showed an early enhanced line around the tumor as rim enhancement; T2 tumors appeared as black lines or double layers, as the muscularis propria kept its integrity; T3 tumors showed partial discontinuity of the muscularis propria as a dotted line and a perforated area as an interrupted line. A confidence level scoring system was used, and receiver operating characteristic curves were generated. There were no significant differences at the T1 stage. There were significant differences for observer 1 (P=0.001 for observer 1) at the T2 stage. There were significant differences for both observers (P=0.001 for observer 1 and P=0.005 for observer 2) at the T3 stage. Our criteria for Gd-enhanced dynamic MRI were effective for T3 stage tumors. (author)

  20. Gadolinium diethylenetriamine pentaacetic acid enhanced magnetic resonance imagings in cardiomyopathic hamsters. Histopathologic correlation

    International Nuclear Information System (INIS)

    Aso, Hiroko

    1995-01-01

    To assess the significance of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging, the findings were correlated with histopathological findings in cardiomyopathic hamsters (Bio 14.6). In hamsters given 1 mBq of Gd-DTPA, autoradiography revealed uptake of Gd-DTPA corresponding to the fibrotic tissue. According to the degree of fibrosis and inflammation, the tissue was graded into three. The ratio of contrast enhancement in the fibrotic area to that in the normal area was significantly higher in grade 1 than grades 2 and 3, and in grade 2 than grade 3. Next, hamsters in various age groups were given 0.2 mmol/kg intravenously. In the age group of 2-5 month, contrast enhancement was homogeneously observed in the entire myocardium. In the age group of 8-10 years, it was entirely observed, partly with heterogeneous enhancement. In the age group of 11-12 years, contrast enhancement was not different from that in the normal hamsters. Histological examination revealed that fibrosis changed from grade 1 through grade 3 with advancing age. In conclusion, MR imaging for myocardiopathy showed signal intensity reflecting the fibrotic tissue. Contrast enhancement of MR imaging was stronger when much more inflammatory cells were involved and fibrotic tissues were filled with much more blood vessels. Thus MR imaging may be a promising tool for evaluating the severity of myocardiopathy. (N.K.)

  1. [Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

    Science.gov (United States)

    Ishimoto, Takeshi; Ishihara, Masaru; Ikeda, Takayuki; Kawakami, Momoe

    2008-12-20

    Cardiac late Gadolinium enhancement MR imaging has been shown to allow assessment of myocardial viability in patients with ischemic heart disease. The current standard approach is a 3D inversion recovery sequence at 1.5 Tesla. The aims of this study were to evaluate the technique feasibility and clinical utility of MR viability imaging at 3.0 Tesla in patients with myocardial infarction and cardiomyopathy. In phantom and volunteer studies, the inversion time required to suppress the signal of interests and tissues was prolonged at 3.0 Tesla. In the clinical study, the average inversion time to suppress the signal of myocardium at 3.0 Tesla with respect to MR viability imaging at 1.5 Tesla was at 15 min after the administration of contrast agent (304.0+/-29.2 at 3.0 Tesla vs. 283.9+/-20.9 at 1.5 Tesla). The contrast between infarction and viable myocardium was equal at both field strengths (4.06+/-1.30 at 3.0 Tesla vs. 4.42+/-1.85 at 1.5 Tesla). Even at this early stage, MR viability imaging at 3.0 Tesla provides high quality images in patients with myocardial infarction. The inversion time is significantly prolonged at 3.0 Tesla. The contrast between infarction and viable myocardium at 3.0 Tesla are equal to 1.5 Tesla. Further investigation is needed for this technical improvement, for clinical evaluation, and for limitations.

  2. Magnetic resonance imaging of urinary bladder carcinoma: tumor staging and gadolinium contrast-enhanced imaging

    International Nuclear Information System (INIS)

    Doringer, E.; Joos, H.; Forstner, R.; Schmoller, H.

    1992-01-01

    Forty-nine patients with urinary bladder carcinomas underwent pre-operative examinations using magnetic resonance (MR) imaging. The results of the MR examinations were correlated with the clinical-pathological findings following transurethral resection (TUR) and bimanual palpation (n = 47) or radical cystectomy (n = 2). The results of pre-contrast MR tumor staging (T1, T2), viewing stages Tis-T2 collectively, and subsequent to separate assessments of stages T3b-T4b, were correct 76.6% of the time. Gadolinium-DTPA (Gd-DTPA) contrast-enhanced examinations (pre-contrast T1 and after Gd-DTPA) showed a staging accuracy rate of 85.7%. T2-weighted images did not indicate any advantage when compared to T1-weighted images following Gd-DTPA. The signal intensity ratios of tumor/fat and tumor/muscle tissue were measured on T1-weighted pre-contrast images and following Gd-DTPA and then evaluated statistically, whereby the increased tumor signal intensity was statistically significant (Wilcoxon test, P < 0.01). Due to the relatively short examination time needed for T1-weighted images and the specific tumor enhancement, the administration of Gd-DTPA proves valuable in the diagnosis of bladder carcinomas. T2-weighted images are not necessary. (orig.)

  3. The value of paramagnetic contrast agent gadolinium-DTPA in the diagnosis of pituitary adenomas

    International Nuclear Information System (INIS)

    Nakamura, T.; Schoerner, W.; Bittner, R.C.; Felix, R.

    1988-01-01

    The purpose of this study was to assess the role of MR imaging and the paramagnetic contrast agent Gadolinium-DYPA(Gd-DTPA) in the diagnosis of pituitary macroadenomas. 44 macroadenomas were examined with MRI before and after intravenous application of Gd-DTPA. Gd-DTPA produced excellent enhancement of solid adenoma. The best contrast between adenoma and surrounding structures could be gained on post-Gd T1-weighted images. Post-Gd images were equivalent to pre-Gd images in the evaluation of supra- and infrasellar extensions of macroadenomas. Post-Gd images had advantages in the evaluation of cavernous sinus invasion by adenoma. The difference in degree of contrast enhancement between adenoma and cavernous sinus facilitated the exact evaluation of lateral extension by adenoma in 18 cases. Almost equal degree of enhancement of both structures impaired tumor-sinus contrast in 2 cases. In the other 24 cases the tumor filled the cavernous sinus completely. It is our opinion that Gd-DTPA can be used on a widerspread basis because of its excellent capability to highlight and delineate pituitary adenomas. (orig.)

  4. Ultra-sensitive quantification of lysozyme based on element chelate labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Yang, MingWei; Wu, WeiHua; Ruan, YaJuan; Huang, LiMei; Wu, Zujian; Cai, Yong; Fu, FengFu

    2014-01-01

    Graphical abstract: An ultra-sensitive method for the determination of lysozyme was developed based on the Gd 3+ chelate labeling and CE–ICP–MS. The proposed method has an extremely low detection limit of 3.89 attomole and has been successfully used to detect lysozyme in saliva sample, showing excellent reliability. The success of the present method provides a new possibility for biological assays and clinical diagnoses. -- Highlights: •An ultra-sensitive method for detecting lysozyme based on CE–ICP–MS was described. •The proposed method has an extremely low detection limit of 3.89 attomole. •It can be used to detect trace lysozyme in saliva sample with a satisfied recovery. •The method provides a new potential for sensitive detection of low-abundant proteins. -- Abstract: In this study, an ultra-sensitive method for the quantification of lysozyme based on the Gd 3+ diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry (CE–ICP–MS) was described. The Gd 3+ -tagged lysozyme was effectively separated by capillary electrophoresis (CE) and sensitively determined by inductively coupled plasma mass spectrometry (ICP–MS). Based on the gadolinium-tagging and CE–ICP–MS, the lysozyme was determined within 12 min with an extremely low detection limit of 3.89 attomole (3.89 × 10 −11 mol L −1 for 100 nL of sample injection) and a RSD < 6% (n = 5). The proposed method has been successfully used to detect lysozyme in saliva samples with a recovery of 91–106%, suggesting that our method is sensitive and reliable. The success of the present method provides a new potential for the biological assays and sensitive detection of low-abundant proteins

  5. Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

    Science.gov (United States)

    Schönherr, Jörg; Fernández, Victoria; Schreiber, Lukas

    2005-06-01

    Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h. At 90% humidity, penetration rates were insignificant with the exception of Natrel, for which t(1/2) amounted to 58 h. Rate constants were independent of temperature (15, 25, and 35 degrees C). Permeability decreased with increasing Fe chelate concentration (IDHA and EDTA). At 100% humidity, half-times measured with FeIDHA were 11 h (2 mmol L(-1)), 17 h (10 mmol L(-1)) and 36 h (20 mmol L(-1)), respectively. In the presence of FeEDTA, penetration of CaCl2 was slowed greatly. Half-times for penetration of CaCl2, which were 1.9 h in the absence of FeEDTA, rose to 3.12 h in the presence of an equimolar concentration of EDTA and 13.3 h when the FeEDTA concentration was doubled. Hence, Fe chelates reduced permeability of CMs to CaCl2 and to the Fe chelates themselves. It is suggested that Fe chelates reduced the size of aqueous pores. This view is supported by the fact that rate constants for calcium salts were about 5 times higher than for Fe chelates with the same molecular weights. Adding Tween 20 (5 g L(-1)) as a humectant did not increase permeability to FeIDHA at 90% humidity and below, while addition of glycine betaine did. Penetration of FeCl3 applied at 5 g L(-1) (pH 1.5) was not a first order process as rate constants decreased rapidly with time. Only 2% of the dose penetrated during the first 2 h and less than that in the subsequent 8 h. Recovery was only 70%. This was attributed to the formation of insoluble Fe

  6. Gadolinium-enhanced magnetic resonance angiography in neonates and infants suspected of caval or aortic thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, S. Bruce; Bhutta, Sadaf T.; Buchmann, Robert F. [University of Arkansas for Medical Sciences, Arkansas Children' s Hospital, Little Rock, AR (United States)

    2004-12-01

    Gadolinium-enhanced magnetic resonance angiography (MRA)is a well-established technique in older children and adults. No studies have focused on its use in neonates and small infants. Our objective was to study the use of gadolinium-enhanced MRA in neonates and infants suspected of caval or aortic thrombosis. Materials and Methods:Gadolinium-enhanced MR angiography was performed on seven neonates and small infants for the evaluation of caval or aortic thrombosis. Gadolinium-DTPA at a dose of 0.3 mmol/kg (minimum dose 1 ml) was injected using a power injector (0.2 ml/s). Contrast-enhanced MRA was performed using a 3-D, fast, radiofrequency spoiled gradient-echo sequence (TR/TE: 4.8/1.1, flip angle 45 , matrix 256 x 128, slice thickness 2.6 mm interpolated to 1.3 mm, FOV variable, NEX=1.0). Diagnostic-quality angiograms were obtained in all seven neonates. Superior vena cava thrombosis was identified in two neonates, and abdominal aortic thrombosis was present in one neonate. It is practical to perform gadolinium-enhanced MRA in neonates weighing as little as 600 g for the detection of caval or aortic thrombosis. (orig.)

  7. The use of iodinated and gadolinium contrast media during pregnancy and lactation

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Judith A.W. [St. Bartholomew' s Hospital, Department of Diagnostic Imaging, London (United Kingdom); Thomsen, Henrik S. [Copenhagen University Hospital at Herlev, Department of Diagnostic Radiology 54E2, Herlev (Denmark); Morcos, Sameh K. [Northern General Hospital, Department of Diagnostic Imaging, Sheffield (United Kingdom)

    2005-06-01

    The use of iodinated or gadolinium-based contrast media in pregnant or lactating women often causes concerns in the radiology department because of the principle of not exposing a fetus or neonate to any drugs. Because of the uncertainty about the use of contrast media during pregnancy and lactation, the Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines. An extensive literature search was carried out and summarized in a report. Based on the limited information available, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. Mutagenic and teratogenic effects have not been described after administration of gadolinium or iodinated contrast media. Free iodide in radiographic contrast medium given to the mother has the potential to depress fetal/neonatal thyroid function. Neonatal thyroid function should be checked during the 1st week if iodinated contrast media have been given during pregnancy. No effect on the fetus has been seen after gadolinium contrast media. Only tiny amounts of iodinated or gadolinium-based contrast medium given to a lactating mother reach the milk, and only a minute proportion entering the baby's gut is absorbed. The very small potential risk associated with absorption of contrast medium may be considered insufficient to warrant stopping breast-feeding for 24 h following either iodinated or gadolinium contrast agents. (orig.)

  8. Gadolinium-enhanced magnetic resonance angiography in neonates and infants suspected of caval or aortic thrombosis

    International Nuclear Information System (INIS)

    Greenberg, S. Bruce; Bhutta, Sadaf T.; Buchmann, Robert F.

    2004-01-01

    Gadolinium-enhanced magnetic resonance angiography (MRA)is a well-established technique in older children and adults. No studies have focused on its use in neonates and small infants. Our objective was to study the use of gadolinium-enhanced MRA in neonates and infants suspected of caval or aortic thrombosis. Materials and Methods:Gadolinium-enhanced MR angiography was performed on seven neonates and small infants for the evaluation of caval or aortic thrombosis. Gadolinium-DTPA at a dose of 0.3 mmol/kg (minimum dose 1 ml) was injected using a power injector (0.2 ml/s). Contrast-enhanced MRA was performed using a 3-D, fast, radiofrequency spoiled gradient-echo sequence (TR/TE: 4.8/1.1, flip angle 45 , matrix 256 x 128, slice thickness 2.6 mm interpolated to 1.3 mm, FOV variable, NEX=1.0). Diagnostic-quality angiograms were obtained in all seven neonates. Superior vena cava thrombosis was identified in two neonates, and abdominal aortic thrombosis was present in one neonate. It is practical to perform gadolinium-enhanced MRA in neonates weighing as little as 600 g for the detection of caval or aortic thrombosis. (orig.)

  9. The use of iodinated and gadolinium contrast media during pregnancy and lactation

    International Nuclear Information System (INIS)

    Webb, Judith A.W.; Thomsen, Henrik S.; Morcos, Sameh K.

    2005-01-01

    The use of iodinated or gadolinium-based contrast media in pregnant or lactating women often causes concerns in the radiology department because of the principle of not exposing a fetus or neonate to any drugs. Because of the uncertainty about the use of contrast media during pregnancy and lactation, the Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines. An extensive literature search was carried out and summarized in a report. Based on the limited information available, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. Mutagenic and teratogenic effects have not been described after administration of gadolinium or iodinated contrast media. Free iodide in radiographic contrast medium given to the mother has the potential to depress fetal/neonatal thyroid function. Neonatal thyroid function should be checked during the 1st week if iodinated contrast media have been given during pregnancy. No effect on the fetus has been seen after gadolinium contrast media. Only tiny amounts of iodinated or gadolinium-based contrast medium given to a lactating mother reach the milk, and only a minute proportion entering the baby's gut is absorbed. The very small potential risk associated with absorption of contrast medium may be considered insufficient to warrant stopping breast-feeding for 24 h following either iodinated or gadolinium contrast agents. (orig.)

  10. Study of burnable poisons and gadolinium qualification in light water reactors

    International Nuclear Information System (INIS)

    Nasr, Mohamed.

    1981-09-01

    The aim of this work is to develop a calculation procedure for analyzing light water moderated reactors utilizing gadolinium as a burnable poison. The main points of this work can be summarized as follows: the available cross section data of gadolinium were analysed and corrected whenever it was necessary. The processes which include required precautions for obtaining multigroup cross sections were defined; an exhaustive study of the assumptions used in multicell calculation methods allowed the definition of option to be used for obtaining good results without excessive calculation cost. This study was followed by the interpretation of experimental results; when gadolinium is used in grain structure, a problem of double heterogeneity is encountered. A new calculation method was developed for such situations. Its validity was confirmed by a comparison with the Monte Carlo method; the problems encountered in performing a study of burn up of fuel elements containing gadolinium were analysed and the necessary precautions were established. The effect of the initial charge and geometrical form of the gadolinium and the behavior of lattices during the burn up were examined [fr

  11. Identification and characterization of gadolinium(III) complexes in biological tissue extracts.

    Science.gov (United States)

    Kahakachchi, Chethaka L; Moore, Dennis A

    2010-07-01

    The gadolinium species present in a rat kidney following intravenous administration of a gadolinium-based magnetic resonance contrast agent (Optimark™, Gadoversetamide injection) to a rat was examined in the present study. The major gadolinium species in the supernatant of the rat kidney tissue extracts was determined by reversed-phase liquid chromatography with online inductively coupled plasma optical emission spectrometry (HPLC-ICP-OES). The identity of the compound was established by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) detection. The principal gadolinium(III) complex in a rat kidney tissue extract was identified as Gd-DTPA-BMEA 24 Hrs and 7 days after a single intravenous injection of Optimark™ (gadoversetamide; Gd-DTPA-BMEA) at a dose of 5 mmol Gd/kg body weight. The study demonstrated for the first time the feasibility of the use of two complementary techniques, HPLC-ICP-OES and HPLC-ESI-MS to study the in vivo behavior of gadolinium-based magnetic resonance contrast media.

  12. First experiences with the application of oral gadolinium-DTPA in MR of the minor pelvis

    International Nuclear Information System (INIS)

    Hoetzinger, H.; Salbeck, R.; Toedt, C.; Beyer, H.K.

    1990-01-01

    The use of an oral contrast medium has so far not become a matter of routine in MR of the abdomen. In the present study the use of orally applied gadolinium-DTPA was examined in respect of tumorous diseases in the minor pelvis. 18 patients with tumours in the minor pelvis were examined before and after oral administration of gadolinium-DTPA (Gd-DTPA). 10 ml/kg body weight of a gadolinium DTPA solution were applied in a concentration of 1.0 mmol/l. T 1 -weighted and T 2 -weighted sequences were carried out before application and T 1 -weighted sequences after application. Oral application of gadolinium-DTPA resulted in enhancing the signals of the filled intestinal portions. In 54% of the cases the sequences showed a sharper delineation between tumour and intestine. In 19% the delineation between pathological tissue and intestine on contrast examination was a well defined as in T 2 -weighted contrast images; in 27% of the cases oral administration of gadolinium-DTPA did not yield any additional information. No significant side effects were seen. (orig.) [de

  13. Study of cyclization of chelating compounds using electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Shi Ying; Campbell, J.A.

    2000-01-01

    Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studied: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. (author)

  14. Vaginal distribution and retention of a multiparticulate drug delivery system, assessed by gamma scintigraphy and magnetic resonance imaging.

    Science.gov (United States)

    Mehta, Samata; Verstraelen, Hans; Peremans, Kathelijne; Villeirs, Geert; Vermeire, Simon; De Vos, Filip; Mehuys, Els; Remon, Jean Paul; Vervaet, Chris

    2012-04-15

    For any new vaginal dosage form, the distribution and retention in the vagina has to be assessed by in vivo evaluation. We evaluated the vaginal distribution and retention of starch-based pellets in sheep as live animal model by gamma scintigraphy (using Indium-111 DTPA as radiolabel) and in women via magnetic resonance imaging (MRI, using a gadolinium chelate as contrast agent). A conventional cream formulation was used as reference in both studies. Cream and pellets were administered to sheep (n=6) in a two period-two treatment study and to healthy female volunteers (n=6) via a randomized crossover trial. Pellets (filled into hard gelatin capsule) and cetomacrogol cream, both labeled with Indium-111 DTPA (for gamma scintigraphy) or with gadolinium chelate (for MRI) were evaluated for their intravaginal distribution and retention over a 24h period. Spreading in the vagina was assessed based on the part of the vagina covered with formulation (expressed in relation to the total vaginal length). Vaginal retention of the formulation was quantified based on the radioactivity remaining in the vaginal area (sheep study), or qualitatively evaluated (women study). Both trials indicated a rapid distribution of the cream within the vagina as complete coverage of the vaginal mucosa was seen 1h after dose administration. Clearance of the cream was rapid: about 10% activity remained in the vaginal area of the sheep 12h post-administration, while after 8h only a thin layer of cream was detected on the vaginal mucosa of women. After disintegration of the hard gelatin capsule, the pellet formulation gradually distributed over the entire vaginal mucosa. Residence time of the pellets in the vagina was longer compared to the semi-solid formulation: after 24h 23 ± 7% radioactivity was detected in the vaginal area of the sheep, while in women the pellet formulation was still detected throughout the vagina. A multi-particulate system containing starch-based pellets was identified as a

  15. Effect of other metals on iron bioavailability in presence of a selective chelator

    International Nuclear Information System (INIS)

    Rehman, F.S.

    1995-01-01

    Iron (III) is generally very easily chelated by a number of chelators in the biological environment, either supplied by food or already present there. One of the these chelator is gallic acid. The stability constants of the complexes formed between gallic acid and other trace metals have been determined by a potentiometric method. The data obtained was computed with the help of computer program B est . The resulted Beta values were compared with already known values of iron gallic acid complexes. (author)

  16. Utility of late gadolinium enhancement in pediatric cardiac MRI

    International Nuclear Information System (INIS)

    Etesami, Maryam; Gilkeson, Robert C.; Rajiah, Prabhakar

    2016-01-01

    Late gadolinium enhancement (LGE) cardiac magnetic resonance (MR) imaging sequence is increasingly used in the evaluation of pediatric cardiovascular disorders, and although LGE might be a normal feature at the sites of previous surgeries, it is pathologically seen as a result of extracellular space expansion, either from acute cell damage or chronic scarring or fibrosis. LGE is broadly divided into ischemic and non-ischemic patterns. LGE caused by myocardial infarction occurs in a vascular distribution and always involves the subendocardial portion, progressively involving the outer regions in a waveform pattern. Non-ischemic cardiomyopathies can have a mid-myocardial (either linear or patchy), subepicardial or diffuse subendocardial distribution. Idiopathic dilated cardiomyopathy can have a linear mid-myocardial pattern, while hypertrophic cardiomyopathy can have fine, patchy enhancement in hypertrophied and non-hypertrophied segments as well as right ventricular insertion points. Myocarditis and sarcoidosis have a mid-myocardial or subepicardial pattern of LGE. Fabry disease typically affects the basal inferolateral segment while Danon disease typically spares the septum. Pericarditis is characterized by diffuse or focal pericardial thickening and enhancement. Thrombus, the most common non-neoplastic cardiac mass, is characterized by absence of enhancement in all sequences, while neoplastic masses show at least some contrast enhancement, depending on the pathology. Regardless of the etiology, presence of LGE is associated with a poor prognosis. In this review, we describe the technical modifications required for performing LGE cardiac MR sequence in children, review and illustrate the patterns of LGE in children, and discuss their clinical significance. (orig.)

  17. Utility of late gadolinium enhancement in pediatric cardiac MRI.

    Science.gov (United States)

    Etesami, Maryam; Gilkeson, Robert C; Rajiah, Prabhakar

    2016-07-01

    Late gadolinium enhancement (LGE) cardiac magnetic resonance (MR) imaging sequence is increasingly used in the evaluation of pediatric cardiovascular disorders, and although LGE might be a normal feature at the sites of previous surgeries, it is pathologically seen as a result of extracellular space expansion, either from acute cell damage or chronic scarring or fibrosis. LGE is broadly divided into ischemic and non-ischemic patterns. LGE caused by myocardial infarction occurs in a vascular distribution and always involves the subendocardial portion, progressively involving the outer regions in a waveform pattern. Non-ischemic cardiomyopathies can have a mid-myocardial (either linear or patchy), subepicardial or diffuse subendocardial distribution. Idiopathic dilated cardiomyopathy can have a linear mid-myocardial pattern, while hypertrophic cardiomyopathy can have fine, patchy enhancement in hypertrophied and non-hypertrophied segments as well as right ventricular insertion points. Myocarditis and sarcoidosis have a mid-myocardial or subepicardial pattern of LGE. Fabry disease typically affects the basal inferolateral segment while Danon disease typically spares the septum. Pericarditis is characterized by diffuse or focal pericardial thickening and enhancement. Thrombus, the most common non-neoplastic cardiac mass, is characterized by absence of enhancement in all sequences, while neoplastic masses show at least some contrast enhancement, depending on the pathology. Regardless of the etiology, presence of LGE is associated with a poor prognosis. In this review, we describe the technical modifications required for performing LGE cardiac MR sequence in children, review and illustrate the patterns of LGE in children, and discuss their clinical significance.

  18. The structural response of gadolinium phosphate to pressure

    International Nuclear Information System (INIS)

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    2016-01-01

    Accurate elastic constants for gadolinium phosphate (GdPO 4 ) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO 4 determined under hydrostatic conditions, 128.1(8) GPa (K′=5.8(2)), is markedly different from that obtained with GdPO 4 under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. High pressure Raman and diffraction analysis indicate that the PO 4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO 4 structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO 9 polyhedra. - Graphical abstract: A high-pressure single crystal diffraction study of GdPO 4 with the monazite structure is presented. The elastic behaviour of rare-earth phosphates are believed to be sensitive to shear forces. The bulk modulus of GdPO 4 measured under hydrostatic conditions is 128.1(8) GPa. Compression of the structure is facilitated by bending/twisting of the Gd−O−P links that result in increased distortion in the GdO 9 polyhedra. Display Omitted - Highlights: • The elastic responses of rare-earth phosphates are sensitive to shear forces. • The bulk modulus of GdPO 4 measured under hydrostatic conditions is 128.1(8) GPa. • Twisting of the inter-polyhedral links allows compression of the GdPO 4 structure. • Changes to the GdO 9 polyhedra occur in response to pressure (<7.0 GPa).

  19. Layered gadolinium hydroxides for simultaneous drug delivery and imaging.

    Science.gov (United States)

    Xu, Yadong; Goyanes, Alvaro; Wang, Yuwei; Weston, Andrew J; So, Po-Wah; Geraldes, Carlos F G C; Fogg, Andrew M; Basit, Abdul W; Williams, Gareth R

    2018-02-27

    The potential of the layered gadolinium hydroxide (LGdH) [Gd 2 (OH) 5 ]Cl·yH 2 O (LGdH-Cl) for simultaneous drug delivery and magnetic resonance imaging was explored in this work. Three non-steroidal anti-inflammatory drugs (diclofenac [dic], ibuprofen [ibu], and naproxen [nap]) were intercalated into LGdH-Cl for the first time, using three different routes (ion exchange intercalation, coprecipitation, and exfoliation-self-assembly). X-ray diffraction, elemental microanalysis and IR spectroscopy confirmed successful incorporation of the drug into the interlayer spaces of the LGdH in all cases. From a comparison of the guest anion sizes and interlayer spacings, the active ingredients are believed to adopt intertwined bilayer configurations between the LGdH layers. The materials prepared by coprecipitation in general have noticeably higher drug loadings than those produced by ion exchange or self-assembly, as a result of the incorporation of some neutral drug into the composites. The LGdH-drug intercalates are stable at neutral pH, but rapidly degrade in acidic conditions to free Gd 3+ into solution. While LGdH-nap releases its drug loading into solution very rapidly (within ca. 1.5 h) at pH 7.4, LGdH-dic shows sustained release over 4 h, and LGdH-ibu extends this to 24 h. The latter composites therefore can be incorporated into enteric-coated tablets to provide sustained release in the small intestine. The drug intercalates are highly biocompatible and retain the proton relaxivity properties of the parent LGdH-Cl, with the materials most promising for use as negative contrast agents in MRI. Overall, the LGdH-drug intercalation compounds appear to have great potential for use in theranostic applications.

  20. The structural response of gadolinium phosphate to pressure

    Energy Technology Data Exchange (ETDEWEB)

    Heffernan, Karina M. [Department of Geosciences, Virginia Tech, Blacksburg, VA 24061 (United States); Ross, Nancy L., E-mail: nross@vt.edu [Department of Geosciences, Virginia Tech, Blacksburg, VA 24061 (United States); Spencer, Elinor C. [Department of Geosciences, Virginia Tech, Blacksburg, VA 24061 (United States); Boatner, Lynn A. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2016-09-15

    Accurate elastic constants for gadolinium phosphate (GdPO{sub 4}) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO{sub 4} determined under hydrostatic conditions, 128.1(8) GPa (K′=5.8(2)), is markedly different from that obtained with GdPO{sub 4} under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. High pressure Raman and diffraction analysis indicate that the PO{sub 4} tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO{sub 4} structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO{sub 9} polyhedra. - Graphical abstract: A high-pressure single crystal diffraction study of GdPO{sub 4} with the monazite structure is presented. The elastic behaviour of rare-earth phosphates are believed to be sensitive to shear forces. The bulk modulus of GdPO{sub 4} measured under hydrostatic conditions is 128.1(8) GPa. Compression of the structure is facilitated by bending/twisting of the Gd−O−P links that result in increased distortion in the GdO{sub 9} polyhedra. Display Omitted - Highlights: • The elastic responses of rare-earth phosphates are sensitive to shear forces. • The bulk modulus of GdPO{sub 4} measured under hydrostatic conditions is 128.1(8) GPa. • Twisting of the inter-polyhedral links allows compression of the GdPO{sub 4} structure. • Changes to the GdO{sub 9} polyhedra occur in response to pressure (<7.0 GPa).

  1. Photocatalyzed removal of lead ion from lead-chelator solution

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Hyun; Na, Jung Won; Sung, Ki Woung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    The present study was undertaken to examine the influence of such chelating agents on the ease and speed of photocatalyzed metal removal and deposition. With excess EDTA, the free EDTA competes with Pb for oxidation, and at a ten fold excess, no lead oxidation (hence removal) occurs. With insufficient EDTA, the corresponding initial concentration of Pb-EDTA is decreased; after its destruction, the remaining Pb{sup 2+} is removed more slowly, at rates found with lead nitrate solution. The net result is that the maximum rate of lead deposition occurs at the stoichiometric ratio of 1:1 EDTA : Pb{sup 2+}.

  2. Optimized conditions for chelation of yttrium-90-DOTA immunoconjugates.

    Science.gov (United States)

    Kukis, D L; DeNardo, S J; DeNardo, G L; O'Donnell, R T; Meares, C F

    1998-12-01

    Radioimmunotherapy (RIT) with 90Y-labeled immunoconjugates has shown promise in clinical trials. The macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) binds 90Y with extraordinary stability, minimizing the toxicity of 90Y-DOTA immunoconjugates arising from loss of 90Y to bone. However, reported 90Y-DOTA immunoconjugate product yields have been typically only BAD) was conjugated to the monoclonal antibody Lym-1 via 2-iminothiolane (2IT). The immunoconjugate product, 2IT-BAD-Lym-1, was labeled in excess yttrium in various buffers over a range of concentrations and pH. Kinetic studies were performed in selected buffers to estimate radiolabeling reaction times under prospective radiopharmacy labeling conditions. The effect of temperature on reaction kinetics was examined. Optimal radiolabeling conditions were identified and used in eight radiolabeling experiments with 2IT-BAD-Lym-1 and a second immunoconjugate, DOTA-peptide-chimeric L6, with 248-492 MBq (6.7-13.3 mCi) of 90Y. Ammonium acetate buffer (0.5 M) was associated with the highest uptake of yttrium. On the basis of kinetic data, the time required to chelate 94% of 90Y (four half-times) under prospective radiopharmacy labeling conditions in 0.5 M ammonium acetate was 17-148 min at pH 6.5, but it was only 1-10 min at pH 7.5. Raising the reaction temperature from 25 degrees C to 37 degrees C markedly increased the chelation rate. Optimal radiolabeling conditions were identified as: 30-min reaction time, 0.5 M ammonium acetate buffer, pH 7-7.5 and 37 degrees C. In eight labeling experiments under optimal conditions, a mean product yield (+/- s.d.) of 91%+/-8% was achieved, comparable to iodination yields. The specific activity of final products was 74-130 MBq (2.0-3.5 mCi) of 90Y per mg of monoclonal antibody. The immunoreactivity of 90Y-labeled immunoconjugates was 100%+/-11%. The optimization of 90Y-DOTA chelation conditions represents an important advance in 90Y RIT

  3. Acidizing reservoirs while chelating iron with sulfosalicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, W A; Berkshire, D C

    1980-09-30

    A well treating process is described in which an aqueous solution of a strong acid capable of dissolving solids in a manner increasing the permeability of a subterranean earth formation is injected into a subterranean reservoir that contains an asphaltenic oil. At least the first injected portion of the aqueous acid and a solution or homogeneous dispersion of at least enough 5-sulfosalicylic acid to chelate with and prevent the formation of iron-asphaltene solids are included with substantially all of the ferric ions that become dissolved within the strong acid solution that enters the earth formation. 10 claims.

  4. Characterization and thermogravimetric analysis of lanthanide hexafluoroacetylacetone chelates.

    Science.gov (United States)

    Shahbazi, Shayan; Stratz, S Adam; Auxier, John D; Hanson, Daniel E; Marsh, Matthew L; Hall, Howard L

    2017-01-01

    This work reports the thermodynamic characterizations of organometallic species as a vehicle for the rapid separation of volatile nuclear fission products via gas chromatography due to differences in adsorption enthalpy. Because adsorption and sublimation thermodynamics are linearly correlated, there is considerable motivation to determine sublimation enthalpies. A method of isothermal thermogravimetric analysis, TGA-MS and melting point analysis are employed on thirteen lanthanide 1,1,1,5,5,5-hexafluoroacetylacetone complexes to determine sublimation enthalpies. An empirical correlation is used to estimate adsorption enthalpies of lanthanide complexes on a quartz column from the sublimation data. Additionally, four chelates are characterized by SC-XRD, elemental analysis, FTIR and NMR.

  5. Uranium and neodymium biosorption using novel chelating polysaccharide.

    Science.gov (United States)

    Elsalamouny, Ahmed R; Desouky, Osman A; Mohamed, Saad A; Galhoum, Ahmed A; Guibal, Eric

    2017-11-01

    A direct reaction is described to prepare hydrophobic α-aminomethylphosphonic acid as a novel chitosan-based material. It exhibits chelating properties for polyvalent metal ions such as U(VI) and Nd(III) ions. The new sorbent was fully characterized using Elemental analysis, scanning electron microscope (SEM) and FTIR spectra. Different parameters were examined in order to evaluate the optimum conditions for U(VI) and Nd(III) ions biosorption. Sorption mechanisms of metal ions were investigated using kinetic and isotherm models. In addition, the sorbent selectivity was tested for both metal ions together in a binary solution. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    OpenAIRE

    Liren Fan; Jiqing Song; Wenbo Bai; Shengping Wang; Ming Zeng; Xiaoming Li; Yang Zhou; Haifeng Li; Haiwei Lu

    2016-01-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shel...

  7. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2. 1998 annual progress report

    International Nuclear Information System (INIS)

    Brennecke, J.F.; Chateauneuf, J.E.; Stadtherr, M.A.

    1998-01-01

    'This report summarizes work after 1 year and 8 months (9/15/96-5/14/98) of a 3 year project. Thus far, progress has been made in: (1) the measurement of the solubility of metal chelates in SC CO 2 with and without added cosolvents, (2) the spectroscopic determination of preferential solvation of metal chelates by cosolvents in SC CO 2 solutions, and (3) the development of a totally reliable computational technique for phase equilibrium computations. An important factor in the removal of metals from solid matrices with CO 2 /chelate mixtures is the equilibrium solubility of the metal chelate complex in the CO 2 .'

  8. Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

    Directory of Open Access Journals (Sweden)

    Dalia Z. Zidan

    2014-06-01

    Conclusion: Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.

  9. Characterization of composite metal-ceramic of nickel-oxide cerium doped gadolinium

    International Nuclear Information System (INIS)

    Silva, M.L.A. da; Varela, M.C.R.S.

    2016-01-01

    Composite nickel doped cerium oxide are used in SOFC anode materials. In this study we evaluated the effect of the presence of gadolinium on the properties of composite nickel and ceria and. The supports were synthesized by sol-gel method. The impregnation with nickel nitrate was taken sequentially, followed by calcination. The materials were characterized by X-ray diffraction, measurement of specific surface area, temperature programmed reduction, Raman spectroscopy. The presence of gadolinium retained the fluorite structure of ceria by forming a solid solution, also not influencing significantly on the specific surface area of the support. On the other hand, there was a decrease in the area catalysts, which can be attributed to sintering of nickel. Furthermore, addition of gadolinium favored the formation of intrinsic and extrinsic vacancies in cerium oxide, which leads to an increase in the ionic conductivity of the solid, desirable property for an SOFC anode catalyst. (author)

  10. Biodistribution of ultra small gadolinium-based nanoparticles as theranostic agent: application to brain tumors.

    Science.gov (United States)

    Miladi, Imen; Duc, Géraldine Le; Kryza, David; Berniard, Aurélie; Mowat, Pierre; Roux, Stéphane; Taleb, Jacqueline; Bonazza, Pauline; Perriat, Pascal; Lux, François; Tillement, Olivier; Billotey, Claire; Janier, Marc

    2013-09-01

    Gadolinium-based nanoparticles are novel objects with interesting physical properties, allowing their use for diagnostic and therapeutic applications. Gadolinium-based nanoparticles were imaged following intravenous injection in healthy rats and rats grafted with 9L gliosarcoma tumors using magnetic resonance imaging and scintigraphic imaging. Quantitative biodistribution using gamma-counting of each sampled organ confirmed that these nanoparticles were rapidly cleared essentially by renal excretion. Accumulation of these nanoparticles in 9L gliosarcoma tumors implanted in the rat brain was quantitated. This passive and long-duration accumulation of gadolinium-based nanoparticles in tumor, which is related to disruption of the blood-brain barrier, is in good agreement with the use of these nanoparticles as radiosensitizers for brain tumors.

  11. Isotope shifts in odd and even energy levels of the neutral and singly ionised gadolinium atom

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Venugopalan, A.; Saksena, G.D.

    1979-01-01

    Isotope shift studies in the gadolinium spectra have been extended in the region 4140 to 4535 A. Isotope shift Δσ(156 to 160) have been measured in 315 lines of the neutral and singly ionised gadolinium atom using a recording Fabry-Perot Spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. Some of the Gd I lines studied involve transitions from newly identified high odd levels of 4f 8 6s6p, 4f 7 5d6s7s and 4f 7 5d 3 configurations to low even levels of 4f 8 6s 2 and 4f 7 6s 2 6p configurations. Electronic configurations of the energy levels have been discussed on the basis of observed isotope shifts. In some cases assigned configurations have been revised and probable configurations have been suggested. (author)

  12. MR arthrography gadolinium versus standard MR imaging in rotator cuff pathology

    International Nuclear Information System (INIS)

    Hodler, J.; Brahme, S.K.; Karzel, R.; Cervilla, V.; Snyder, S.; Schweitzer, M.; Flannigan, B.; Resnick, D.

    1990-01-01

    This paper compares the accuracy of MR imaging with and without intraarticular gadolinium in the diagnosis of rotator cuff pathology, using arthroscopy as the gold standard. The authors examined 36 patients, first with T2-weighted sequences and then with T1-weighted sequences after the injection of 15-20 mL of diluted gadolinium. The images were read blindly by three radiologists experienced in musculoskeletal MR imaging. The results were compared with those of arthroscopy. In 16 of 19 arthroscopically intact rotator cuffs, both sequences demonstrated no evidence of rotator cuff tear. The remaining three cases were interpreted as partial or full-thickness tears. Of 12 partial tears, T1-weighted images with intraarticular gadolinium demonstrated a partial tear in five, degeneration in four, a full thickness tear in two, and a normal rotator cuff in one

  13. Modeling gadolinium-bearing fuel in Ringhals PWRs using CASMO/SIMULATE

    International Nuclear Information System (INIS)

    Kurcyusz, E.

    1993-01-01

    Ringhals units 2, 3, and 4 are Westinghouse three-loop, 157-assembly pressurized water reactors (PWRs) operated by Vattenfall. Originally, all three reactors were loaded in an out-in scheme using reload fuel without burnable poisons. In recent cycles, gadolinium-bearing fuel was introduced to enable a low-leakage loading pattern and minimize fuel cycle costs. This paper focuses on the Fragema 17 x 17 AFA design with peripheral gadolinium rods loaded in units 3 and 4. The Ringhals units are modeled using the Studsvik core management system, consisting of the CASMO-3 transport theory lattice physics code,and the SIMULATE-3 advanced nodal reactor analysis code. The results of the studies verifying the accuracy of CASMO-3/SIMULATE-3 on the assemblies with peripheral gadolinium rods are presented in this paper. The verification was carried out against CASMO-3 color-set calculations and measured reactor data

  14. Feasibility of using gadolinium as a burnable poison in PWR cores. Final report

    International Nuclear Information System (INIS)

    Rothleder, B.M.

    1981-02-01

    As an alternative to the use of lumped burnable absorbers in PWR cores, distributed burnable absorbers are being considered for generic application. These burnable absorbers take the form of Gd 2 O 3 mixed with UO 2 in selected fuel rods (as is currently done in BWR cores). The work discussed herein concerns a three-dimensional feasibility study of the use of such distributed burnable absorbers in PWR cores. This study of distributed burnable absorbers was performed for the first cycle of a typical current design PWR using the following steps: analysis of a generic reference core design; determination of gadolinium assembly designs; determination of a generic gadolinium core design; evaluation of feasibility by examining selected parameters; and redesign of the generic gadolinium core, using axial zoning

  15. Spectral, Electrochemical, Fluorescence, Kinetic and Anti-microbial Studies of Acyclic Schiff-base Gadolinium(III) Complexes

    International Nuclear Information System (INIS)

    Vijayaraj, A.; Prabu, R.; Suresh, R.; Narayanan, V.; Sangeetha Kumari, R.; Kaviyarasan, V.

    2012-01-01

    A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in the cavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexes show irreversible one electron reduction process around -2.15 to -1.60 V. The reduction potential of gadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. The catalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determined. All gadolinium(III) complexes were screened for antibacterial activity

  16. Spectral, Electrochemi