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Sample records for agents including gadolinium

  1. [Gadolinium-based contrast agents for magnetic resonance imaging].

    PubMed

    Carrasco Muñoz, S; Calles Blanco, C; Marcin, Javier; Fernández Álvarez, C; Lafuente Martínez, J

    2014-06-01

    Gadolinium-based contrast agents are increasingly being used in magnetic resonance imaging. These agents can improve the contrast in images and provide information about function and metabolism, increasing both sensitivity and specificity. We describe the gadolinium-based contrast agents that have been approved for clinical use, detailing their main characteristics based on their chemical structure, stability, and safety. In general terms, these compounds are safe. Nevertheless, adverse reactions, the possibility of nephrotoxicity from these compounds, and the possibility of developing nephrogenic systemic fibrosis will be covered in this article. Lastly, the article will discuss the current guidelines, recommendations, and contraindications for their clinical use, including the management of pregnant and breast-feeding patients.

  2. Tumor growth suppression by gadolinium-neutron capture therapy using gadolinium-entrapped liposome as gadolinium delivery agent.

    PubMed

    Dewi, Novriana; Yanagie, Hironobu; Zhu, Haito; Demachi, Kazuyuki; Shinohara, Atsuko; Yokoyama, Kazuhito; Sekino, Masaki; Sakurai, Yuriko; Morishita, Yasuyuki; Iyomoto, Naoko; Nagasaki, Takeshi; Horiguchi, Yukichi; Nagasaki, Yukio; Nakajima, Jun; Ono, Minoru; Kakimi, Kazuhiro; Takahashi, Hiroyuki

    2013-07-01

    Neutron capture therapy (NCT) is a promising non-invasive cancer therapy approach and some recent NCT research has focused on using compounds containing gadolinium as an alternative to currently used boron-10 considering several advantages that gadolinium offers compared to those of boron. In this study, we evaluated gadolinium-entrapped liposome compound as neutron capture therapy agent by in vivo experiment on colon-26 tumor-bearing mice. Gadolinium compound were injected intravenously via tail vein and allowed to accumulate into tumor site. Tumor samples were taken for quantitative analysis by ICP-MS at 2, 12, and 24 h after gadolinium compound injection. Highest gadolinium concentration was observed at about 2 h after gadolinium compound injection with an average of 40.3 μg/g of wet tumor tissue. We performed neutron irradiation at JRR-4 reactor facility of Japan Atomic Energy Research Institute in Tokaimura with average neutron fluence of 2×10¹² n/cm². The experimental results showed that the tumor growth suppression of gadolinium-injected irradiated group was revealed until about four times higher compared to the control group, and no significant weight loss were observed after treatment suggesting low systemic toxicity of this compound. The gadolinium-entrapped liposome will become one of the candidates for Gd delivery system on NCT.

  3. Brain gadolinium deposition after administration of gadolinium-based contrast agents.

    PubMed

    Kanda, Tomonori; Oba, Hiroshi; Toyoda, Keiko; Kitajima, Kazuhiro; Furui, Shigeru

    2016-01-01

    Gadolinium-based contrast agents (GBCAs) consist of gadolinium ions and a chelating agent that binds the gadolinium ion tightly so that its toxicity is not manifested. However, in 2013, an association between brain MRI abnormalities and a history of GBCA administration was first reported. Even in patients with normal renal function, increased signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted images showed a positive correlation with previous exposure to linear chelate type GBCAs, but not to macrocyclic chelate type ones. This difference of GBCAs is speculated to reflect the stability of GBCAs, and de-chelated gadolinium deposition has been strongly suspected. Using inductively coupled plasma mass spectroscopy, gadolinium was detected from patients' brains with a history of repeated GBCA administration. In some cases, the gadolinium concentration of a patient's brain with normal renal function exceeded the gadolinium concentration of the skin in nephrogenic systemic fibrosis patients, but without any histological change. The actual risk has not been documented yet, but it seems important to consider the potential unknown risks of residual gadolinium in our decisions regarding GBCA administration, and to make efforts to minimize any residual gadolinium in the patient's body.

  4. Gadolinium nanoparticles and contrast agent as radiation sensitizers.

    PubMed

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-07

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist(®) in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL(-1)), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly 'energy dependent' for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs.

  5. Gadolinium nanoparticles and contrast agent as radiation sensitizers

    NASA Astrophysics Data System (ADS)

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F.; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-01

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist® in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL-1), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly ‘energy dependent’ for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs.

  6. DNA surface modified gadolinium phosphate nanoparticles as MRI contrast agents.

    PubMed

    Dumont, Matthieu F; Baligand, Celine; Li, Yichen; Knowles, Elisabeth S; Meisel, Mark W; Walter, Glenn A; Talham, Daniel R

    2012-05-16

    Oligonucleotide modified gadolinium phosphate nanoparticles have been prepared and their magnetic resonance relaxivity properties measured. Nanoparticles of GdPO4·H2O were synthesized in a water/oil microemulsion using IGEPAL CO-520 as surfactant, resulting in 50 to 100 nm particles that are highly dispersible and stable in water. Using surface modification chemistry previously established for zirconium phosphonate surfaces, the particles are directly modified with 5'-phosphate terminated oligonucleotides, and the specific interaction of the divalent phosphate with Gd(3+) sites at the surface is demonstrated. The ability of the modified nanoparticles to act as MRI contrast agents was determined by performing MR relaxivity measurements at 14.1 T. Solutions of nanopure water, Feridex, and Omniscan (FDA approved contrast agents) in 0.25% agarose were used for comparison and control purposes. MRI data confirm that GdPO4·H2O nanoparticles have relaxivities (r1, r2) comparable to those of commercially available contrast agents. In addition, the data suggest that biofunctionalization of the surface of the nanoparticles does not prevent their function as MRI contrast agents.

  7. The presence of the gadolinium-based contrast agent depositions in the brain and symptoms of gadolinium neurotoxicity - A systematic review

    PubMed Central

    Olchowy, Cyprian; Cebulski, Kamil; Łasecki, Mateusz; Chaber, Radosław; Olchowy, Anna; Kałwak, Krzysztof; Zaleska-Dorobisz, Urszula

    2017-01-01

    Background and purpose Gadolinium based contrast agents (GBCAs) are widely used in magnetic resonance imaging, but recently, high signal intensity in the cerebellum structures was reported after repeated administrations of contrast- enhanced magnetic resonance images. The aim of this systematic review was to investigate the association between increased signal intensity in the dentate nucleus and globus pallidus in the brain and repeated administrations of GBCAs. Additionally, we focused on possible short- and long-term consequences of gadolinium use in those patients. Methods Systematic review of retrospective investigations in PubMed and Medline was performed in July 2016. Primary outcomes included the presence of increased signal intensity within the dentate nucleus and globus pallidus on unenhanced T1-weighted MR images in patients following administrations of GBCAs. Two independent reviewers were responsible for search and data extraction. Results 25 publications satisfied inclusion criteria (19 magnetic resonance images analyses, 3 case reports; 3 autopsy studies). Magnetic resonance images of 1247 patients with increased signal intensity on unenhanced T1-weighted MR images were analyzed as well as tissue specimens from 27 patients. Signal intensity correlated positively with the exposure to GBCAs and was greater after serial administrations of linear nonionic than cyclic contrast agents. Gadolinium was detected in all tissue examinations. Conclusions High signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted magnetic resonance images were associated with previous administration of GBCAs. Signal intensity correlated negatively with stability of contrast agents. Clinical significance of gadolinium deposition in the brain remains unclear. There is a strong need for further research to identify type of gadolinium deposited in the brain as well as to gather knowledge about long-term consequences. PMID:28187173

  8. Gadolinium-based contrast agents: did we miss something in the last 25 years?

    PubMed

    Beomonte Zobel, Bruno; Quattrocchi, Carlo Cosimo; Errante, Yuri; Grasso, Rosario Francesco

    2016-06-01

    In the last 24 months, several clinical and experimental studies, suggested first and demonstrated later, a progressive concentration of Gadolinium in the brain of normal renal function patients, following repeated injections of some of the commercially approved Gadolinium-Based Contrast Agents. Although, till now, Gadolinium brain deposits have not been associated to any kind of neurological signs or symptoms, they oblige the radiology community to modify the actual approach in using Gadolinium contrast media in daily practice, to reduce unknown possible risks for patients.

  9. Gadolinium contrast agent-induced CD163+ ferroportin+ osteogenic cells in nephrogenic systemic fibrosis.

    PubMed

    Swaminathan, Sundararaman; Bose, Chhanda; Shah, Sudhir V; Hall, Kimberly A; Hiatt, Kim M

    2013-09-01

    Gadolinium-based contrast agents are linked to nephrogenic systemic fibrosis in patients with renal insufficiency. The pathology of nephrogenic systemic fibrosis is characterized by abnormal tissue repair: fibrosis and ectopic ossification. The mechanisms by which gadolinium could induce fibrosis and ossification are not known. We examined in vitro the effect of a gadolinium-based contrast agent on human peripheral blood mononuclear cells for phenotype and function relevant to the pathology of nephrogenic systemic fibrosis using immunofluorescence, flow cytometry, real-time PCR, and osteogenic assays. We also examined tissues from patients with nephrogenic systemic fibrosis, using IHC to identify the presence of cells with phenotype induced by gadolinium. Gadolinium contrast induced differentiation of human peripheral blood mononuclear cells into a unique cellular phenotype--CD163(+) cells expressing proteins involved in fibrosis and bone formation. These cells express fibroblast growth factor (FGF)23, osteoblast transcription factors Runt-related transcription factor 2, and osterix, and show an osteogenic phenotype in in vitro assays. We show in vivo the presence of CD163(+)/procollagen-1(+)/osteocalcin(+) cells in the fibrotic and calcified tissues of nephrogenic systemic fibrosis patients. Gadolinium contrast-induced CD163(+)/ferroportin(+)/FGF23(+) cells with osteogenic potential may play a role in systemic fibrosis and ectopic ossification in nephrogenic systemic fibrosis.

  10. Biocompatible nanotemplate-engineered nanoparticles containing gadolinium: stability and relaxivity of a potential MRI contrast agent.

    PubMed

    Zhu, Donghua; White, R D; Hardy, Peter A; Weerapreeyakul, Natthida; Sutthanut, Khaetthareeya; Jay, Michael

    2006-04-01

    In this article, we use a nanotemplate engineering approach to prepare biodegradable nanoparticles composed of FDA-approved materials and possessing accessible gadolinium (Gd) atoms and demonstrate their potential as a Magnetic Resonance Imaging (MRI) contrast agent. Nanoparticles containing dimyristoyl phosphoethanolamine diethylene triamine penta acetate (PE-DTPA) were prepared using 3.5 mg of Brij 78, 2.0 mg of emulsifying wax and 0.5 mg of PE-DTPA/ml from a microemulsion precursor. After the addition of GdCl3, the presence of Gd on the surface of nanoparticles was characterized using inductively coupled plasma atomic emission spectroscopy and Scanning Transmission Electron Microscopy (STEM). The in vitro relaxivities of the PE-DTPA-Gd nanoparticles in different media were assessed at different field strengths. The conditional stability constant of Gd binding to the nanoparticles was determined using competitive spectrophotometric titration. Transmetallation kinetics of the gadolinium ion from PE-DTPA-Gd nanoparticles with zinc as the competing ionic was measured using the relaxivity evolution method. Nanoparticles with a diameter of approximately 130 nm possessing surface chelating functions were made from GRAS (Generally Regarded As Safe) materials. STEM demonstrated the uniform distribution of Gd3+ on the surface of the nanoparticles. The thermodynamic binding constant for Gd3+ to the nanoparticles was approximately 10(18) M(-1) and transmetallation studies with Zn2+ yielded kinetic constants K1 and K(-1) of 0.033 and 0.022 1/h, respectively, with an equilibrium constant of 1.5. A payload of approximately 10(5) Gd/nanoparticle was achieved; enhanced relaxivities were observed, including a pH dependence of the transverse relaxivity (r2). Nanoparticles composed of materials that have been demonstrated to be hemocompatible and enzymatically metabolized and possessing accessible Gd ions on their surface induce relaxivities in the bulk water signal that make them

  11. The evolution of gadolinium based contrast agents: from single-modality to multi-modality

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Liu, Ruiqing; Peng, Hui; Li, Penghui; Xu, Zushun; Whittaker, Andrew K.

    2016-05-01

    Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications.

  12. Thermal Excitation of Gadolinium-Based Contrast Agents Using Spin Resonance

    PubMed Central

    Fridjhon, Peter; Rubin, David M.

    2016-01-01

    Theoretical and experimental investigations into the thermal excitation of liquid paramagnetic contrast agents using the spin resonance relaxation mechanism are presented. The electronic spin-lattice relaxation time τ1e of gadolinium-based contrast agents, which is estimated at 0.1 ns, is ten orders of magnitude faster than the relaxation time of protons in water. The shorter relaxation time is found to significantly increase the rate of thermal energy deposition. To the authors’ knowledge this is the first study of gadolinium based contrast agents in a liquid state used as thermal agents. Analysis shows that when τ1e and other experimental parameters are optimally selected, a maximum theoretical heating rate of 29.4 °C.s−1 could be achieved which would suffice for clinical thermal ablation of neoplasms. The experimental results show a statistically significant thermal response for two out of the four contrast agents tested. The results are compared to the simulated estimates via analysis of a detailed model of the system. While these experimentally determined temperature rises are small and thus of no clinical utility, their presence supports the theoretical analysis and strongly suggests that the chemical structure of the selected compounds plays an important role in this mechanism of heat deposition. There exists an opportunity for the development of alternative gadolinium-based compounds with an order of magnitude longer τ1e in a diluted form to be used as an efficient hyperthermia agent for clinical use. PMID:27341338

  13. Removal of gadolinium-based contrast agents: adsorption on activated carbon.

    PubMed

    Elizalde-González, María P; García-Díaz, Esmeralda; González-Perea, Mario; Mattusch, Jürgen

    2017-01-31

    Three carbon samples were employed in this work, including commercial (1690 m(2) g(-1)), activated carbon prepared from guava seeds (637 m(2) g(-1)), and activated carbon prepared from avocado kernel (1068 m(2) g(-1)), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with H3PO4 were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity. The kinetic adsorption curves were described by a pseudo-second-order equation, and the adsorption isotherms in the concentration range 0.5-6 mM fit the Freundlich equation. The chemical characterization of the surfaces shows that materials with a greater amount of phenolic functional groups adsorb the GBCA better. Adsorption strongly depends on the pH due to the combination of the following factors: contrast agent protonated forms and carbon surface charge. The tested carbon samples were able to adsorb 70-90% of GBCA in aqueous solution and less in model urine. This research proposes a method for the elimination of GBCA from patient urine before its discharge into wastewater.

  14. [Physico-chemical and toxicological profile of gadolinium chelates as contrast agents for magnetic resonance imaging].

    PubMed

    Idée, J-M; Fretellier, N; Thurnher, M M; Bonnemain, B; Corot, C

    2015-07-01

    Gadolinium chelates (GC) are contrast agents widely used to facilitate or to enable diagnosis using magnetic resonance imaging (MRI). From a regulatory viewpoint, GC are drugs. GC have largely contributed to the success of MRI, which has become a major component of clinician's diagnostic armamentarium. GC are not metabolised and are excreted by the kidneys. They distribute into the extracellular compartment. Because of its high intrinsic toxicity, gadolinium must be administered as a chelate. GC can be classified according to two key molecular features: (a) nature of the chelating moiety: either macrocyclic molecules in which gadolinium is caged in the pre-organized cavity of the ligand, or linear, open-chain molecules, (b) ionicity: Gd chelates can be ionic (meglumine or sodium salts) or non-ionic. The thermodynamic and kinetic stabilities of the various GCs differ according to these structural characteristics. The kinetic stability of macrocyclic GCs is much higher than that of linear GCs and the thermodynamic stability of ionic GCs is generally higher than that of non-ionic GC, thus leading to a lower risk of gadolinium dissociation. This class of drugs has enjoyed an excellent reputation in terms of safety for a long time, until a causal link with a recently-described serious disease, nephrogenic systemic fibrosis (NSF), was evidenced. It is acknowledged that the vast majority of NSF cases are related to the administration of some linear CG in renally-impaired patients. Health authorities, worldwide, released recommendations which drastically reduced the occurrence of new cases.

  15. Analytical Interference in Serum Iron Determination Reveals Iron Versus Gadolinium Transmetallation With Linear Gadolinium-Based Contrast Agents

    PubMed Central

    Fretellier, Nathalie; Poteau, Nathalie; Factor, Cécile; Mayer, Jean-François; Medina, Christelle; Port, Marc; Idée, Jean-Marc; Corot, Claire

    2014-01-01

    Objectives The purposes of this study were to evaluate the risk for analytical interference with gadolinium-based contrast agents (GBCAs) for the colorimetric measurement of serum iron (Fe3+) and to investigate the mechanisms involved. Materials and Methods Rat serum was spiked with several concentrations of all molecular categories of GBCAs, ligands, or “free” soluble gadolinium (Gd3+). Serum iron concentration was determined by 2 different colorimetric methods at pH 4.0 (with a Vitros DT60 analyzer or a Cobas Integra 400 analyzer). Secondly, the cause of interference was investigated by (a) adding free soluble Gd3+ or Mn2+ to serum in the presence of gadobenic acid or gadodiamide and (b) electrospray ionization mass spectrometry. Results Spurious decrease in serum Fe3+ concentration was observed with all linear GBCAs (only with the Vitros DT60 technique occurring at pH 4.0) but not with macrocyclic GBCAs or with free soluble Gd3+. Spurious hyposideremia was also observed with the free ligands present in the pharmaceutical solutions of the linear GBCAs gadopentetic acid and gadodiamide (ie, diethylene triamine pentaacetic acid and calcium-diethylene triamine pentaacetic acid bismethylamide, respectively), suggesting the formation of Fe-ligand chelate. Gadobenic acid-induced interference was blocked in a concentration-dependent fashion by adding a free soluble Gd3+ salt. Conversely, Mn2+, which has a lower affinity than Gd3+ and Fe3+ for the ligand of gadobenic acid (ie, benzyloxypropionic diethylenetriamine tetraacetic acid), was less effective (interference was only partially blocked), suggesting an Fe3+ versus Gd3+ transmetallation phenomenon at pH 4.0. Similar results were observed with gadodiamide. Mass spectrometry detected the formation of Fe-ligand with all linear GBCAs tested in the presence of Fe3+ and the disappearance of Fe-ligand after the addition of free soluble Gd3+. No Fe-ligand chelate was found in the case of the macrocyclic GBCA gadoteric

  16. Surface Modified Gadolinium Phosphate Nanoparticles as MRI Contrast Agents

    NASA Astrophysics Data System (ADS)

    Dumont, Matthieu F.; Baligand, Celine; Knowles, Elisabeth S.; Meisel, Mark W.; Walter, Glenn A.; Talham, Daniel R.

    2012-02-01

    Nanoparticles of GdPO4H2O were synthesized in a water/oil microemulsion using IGEPAL CO-520 as surfactant resulting in 50 nm to 100 nm particles that are dispersible and stable in water. Using surface modification chemistry previously established for zirconium phosphonate surfaces,ootnotetext J. Monot et al., J. Am. Chem. Soc. 130 (2008) 6243. the particles are directly modified with 5'-phosphate terminated oligonucleotides, and the specific interaction of the divalent phosphate with Gd^3+ sites at the surface is demonstrated. The ability of the modified nanoparticles to act as MRI contrast agents was determined by performing MR relaxivity measurements at 14 T. Solutions of nanopure water, Feridex and Omniscan (FDA cleared contrast agents) in 0.25% agarose were used for comparison and control purposes. MRI data confirm that GdPO4H2O nanoparticles have relaxivities (r1,r2) comparable to commercially available contrast agents.ootnotetext H. Hifumi et al., J. Am. Chem. Soc. 128 (2006) 15090. In addition, biofunctionalization of the surface of the nanoparticles does not prevent their function as MRI contrast agents.

  17. Active extravasation of gadolinium-based contrast agent into the subdural space following lumbar puncture.

    PubMed

    Kothari, Pranay D; Hanser, Evelyn M; Wang, Harrison; Farid, Nikdokht

    2016-01-01

    A 38year-old male presented with cauda equina syndrome following multiple lumbar puncture attempts. Lumbar spine magnetic resonance imaging (MRI) showed a subdural hematoma and an area of apparent contrast enhancement in the spinal canal on sagittal post-contrast images. Axial post-contrast images obtained seven minutes later demonstrated an increase in size and change in shape of the region of apparent contrast enhancement, indicating active extravasation of the contrast agent. This is the first reported case of active extravasation of gadolinium-based contrast agent in the spine.

  18. Tracing gadolinium-based contrast agents from surface water to drinking water by means of speciation analysis.

    PubMed

    Birka, Marvin; Wehe, Christoph A; Hachmöller, Oliver; Sperling, Michael; Karst, Uwe

    2016-04-01

    In recent decades, a significant amount of anthropogenic gadolinium has been released into the environment as a result of the broad application of contrast agents for magnetic resonance imaging (MRI). Since this anthropogenic gadolinium anomaly has also been detected in drinking water, it has become necessary to investigate the possible effect of drinking water purification on these highly polar microcontaminats. Therefore, a novel highly sensitive method for speciation analysis of gadolinium is presented. For that purpose, the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma-mass spectrometry (ICP-MS) was employed. In order to enhance the detection power, sample introduction was carried out by ultrasonic nebulization. In combination with a novel HILIC method using a diol-based stationary phase, it was possible to achieve superior limits of detection for frequently applied gadolinium-based contrast agents below 20pmol/L. With this method, the contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were determined in concentrations up to 159pmol/L in samples from several waterworks in a densely populated region of Germany alongside the river Ruhr as well as from a waterworks near a catchment lake. Thereby, the direct impact of anthropogenic gadolinium species being present in the surface water on the amount of anthropogenic gadolinium in drinking water was shown. There was no evidence for the degradation of contrast agents, the release of Gd(3+) or the presence of further Gd species.

  19. Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

    PubMed Central

    Ananta, Jeyarama S.; Godin, Biana; Sethi, Richa; Moriggi, Loick; Liu, Xuewu; Serda, Rita E.; Krishnamurthy, Ramkumar; Muthupillai, Raja; Bolskar, Robert D.; Helm, Lothar; Ferrari, Mauro; Wilson, Lon J.; Decuzzi, Paolo

    2010-01-01

    Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties in order to improve relaxivity and to enhance image contrast. Here we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles. For all combinations of nanoconstructs, a boost in longitudinal proton relaxivity r1 was observed: for Magnevist, r1~14 mM-1s-1/Gd3+ion (~8.15×10+7 mM-1s-1/construct); for gadofullerenes, r1~200 mM-1s-1/Gd3+ion (~7×10+9 mM-1s-1/construct); for gadonanotubes, r1~150 mM-1s-1/Gd3+ion (~2×10+9 mM-1s-1/construct). These relaxivity values are about 4 to 50 times larger than that of clinically-available gadolinium-based agents (~4 mM-1s-1 /Gd3+ion). The enhancement in contrast is attributed to the geometrical confinement of the agents, which influences the paramagnetic behavior of the Gd3+ions. Thus, nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents. PMID:20972435

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

    SciTech Connect

    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.

  1. Safety of the Gadolinium-Based Contrast Agents for Magnetic Resonance Imaging, Focusing in Part on Their Accumulation in the Brain and Especially the Dentate Nucleus.

    PubMed

    Runge, Val M

    2016-05-01

    The established class of intravenous contrast media for magnetic resonance imaging is the gadolinium chelates, more generally referred to as the gadolinium-based contrast agents (GBCAs). These can be differentiated on the basis of stability in vivo, with safety and tolerability of the GBCAs dependent upon chemical and biologic inertness. This review discusses first the background in terms of development of these agents and safety discussions therein, and second their relative stability based both on in vitro studies and clinical observations before and including the advent of nephrogenic systemic fibrosis. This sets the stage for the subsequent focus of the review, the current knowledge regarding accumulation of gadolinium in the brain and specifically the dentate nucleus after intravenous administration of the GBCAs and differentiation among agents on this basis. The information available to date, from the initial conception of these agents in 1981 to the latest reports concerning safety, demonstrates a significant difference between the macrocyclic and linear chelates. The review concludes with a discussion of the predictable future, which includes, importantly, a reassessment of the use of the linear GBCAs or a subset thereof.

  2. The use of innovative gadolinium-based contrast agent for MR-diagnosis of cancer in the experiment

    NASA Astrophysics Data System (ADS)

    Chernov, V.; Medvedeva, A.; Sinilkin, I.; Zelchan, R.; Grigorev, E.; Frolova, I.; Nam, I.

    2016-02-01

    The present study of the functional suitability and specific activity of the contrast agent gadolinium-based for magnetic resonance imaging demonstrated that the investigated contrast agent intensively accumulates in organs and anatomical structures of the experimental animals. In the model of tumor lesions in animals, study have shown that investigational contrast agent accumulates in the tumor tissue and retained there in for a long enough time.

  3. Gadolinium(III) complexes as MRI contrast agents: ligand design and properties of the complexes.

    PubMed

    Hermann, Petr; Kotek, Jan; Kubícek, Vojtech; Lukes, Ivan

    2008-06-21

    Magnetic resonance imaging is a commonly used diagnostic method in medicinal practice as well as in biological and preclinical research. Contrast agents (CAs), which are often applied are mostly based on Gd(III) complexes. In this paper, the ligand types and structures of their complexes on one side and a set of the physico-chemical parameters governing properties of the CAs on the other side are discussed. The solid-state structures of lanthanide(III) complexes of open-chain and macrocyclic ligands and their structural features are compared. Examples of tuning of ligand structures to alter the relaxometric properties of gadolinium(III) complexes as a number of coordinated water molecules, their residence time (exchange rate) or reorientation time of the complexes are given. Influence of the structural changes of the ligands on thermodynamic stability and kinetic inertness/lability of their lanthanide(III) complexes is discussed.

  4. Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI.

    PubMed

    Doiron, Amber L; Chu, Kevin; Ali, Adeel; Brannon-Peppas, Lisa

    2008-11-11

    Accurate imaging of atherosclerosis is a growing necessity for timely treatment of the disease. Magnetic resonance imaging (MRI) is a promising technique for plaque imaging. The goal of this study was to create polymeric particles of a small size with high loading of diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) and demonstrate their usefulness for MRI. A water-in-oil-in-oil double emulsion solvent evaporation technique was used to encapsulate the MRI agent in a poly(lactide-co-glycolide) (PLGA) or polylactide-poly(ethylene glycol) (PLA-PEG) particle for the purpose of concentrating the agent at an imaging site. PLGA particles with two separate average sizes of 1.83 microm and 920 nm, and PLA-PEG particles with a mean diameter of 952 nm were created. Loading of up to 30 wt % Gd-DTPA was achieved, and in vitro release occurred over 5 h. PLGA particles had highly negative zeta potentials, whereas the particles incorporating PEG had zeta potentials closer to neutral. Cytotoxicity of the particles on human umbilical vein endothelial cells (HUVEC) was shown to be minimal. The ability of the polymeric contrast agent formulation to create contrast was similar to that of Gd-DTPA alone. These results demonstrate the possible utility of the contrast agent-loaded polymeric particles for plaque detection with MRI.

  5. Efficient labeling in vitro with non-ionic gadolinium magnetic resonance imaging contrast agent and fluorescent transfection agent in bone marrow stromal cells of neonatal rats

    PubMed Central

    LI, YING-QIN; TANG, YING; FU, RAO; MENG, QIU-HUA; ZHOU, XUE; LING, ZE-MIN; CHENG, XIAO; TIAN, SU-WEI; WANG, GUO-JIE; LIU, XUE-GUO; ZHOU, LI-HUA

    2015-01-01

    Although studies have been undertaken on gadolinium labeling-based molecular imaging in magnetic resonance imaging (MRI), the use of non-ionic gadolinium in the tracking of stem cells remains uncommon. To investigate the efficiency in tracking of stem cells with non-ionic gadolinium as an MRI contrast agent, a rhodamine-conjugated fluorescent reagent was used to label bone marrow stromal cells (BMSCs) of neonatal rats in vitro, and MRI scanning was undertaken. The fluorescent-conjugated cell uptake reagents were able to deliver gadodiamide into BMSCs, and cell uptake was verified using flow cytometry. In addition, the labeled stem cells with paramagnetic contrast medium remained detectable by an MRI monitor for a minimum of 28 days. The present study suggested that this method can be applied efficiently and safely for the labeling and tracking of bone marrow stromal cells in neonatal rats. PMID:25816076

  6. Gadolinium(III) Complexes with N-Alkyl-N-methylglucamine Surfactants Incorporated into Liposomes as Potential MRI Contrast Agents

    PubMed Central

    Silva, Simone Rodrigues; Duarte, Érica Correia; Ramos, Guilherme Santos; Kock, Flávio Vinícius Crizóstomo; Andrade, Fabiana Diuk; Frézard, Frédéric; Colnago, Luiz Alberto; Demicheli, Cynthia

    2015-01-01

    Complexes of gadolinium(III) with N-octanoyl-N-methylglucamine (L8) and N-decanoyl-N-methylglucamine (L10) with 1 : 2 stoichiometry were synthesized and characterized by elemental analysis, electrospray ionization-tandem mass spectrometry (ESI-MS), infrared (IR) spectroscopy, and molar conductivity measurements. The transverse (r2) and longitudinal (r1) relaxivity protons were measured at 20 MHz and compared with those of the commercial contrasts. These complexes were incorporated in liposomes, resulting in the increase of the vesicle zeta potential. Both the free and liposome-incorporated gadolinium complexes showed high relaxation effectiveness, compared to commercial contrast agent gadopentetate dimeglumine (Magnevist). The high relaxivity of these complexes was attributed to the molecular rotation that occurs more slowly, because of the elevated molecular weight and incorporation in liposomes. The results establish that these paramagnetic complexes are highly potent contrast agents, making them excellent candidates for various applications in molecular MR imaging. PMID:26347596

  7. Speciation and isotope dilution analysis of gadolinium-based contrast agents in wastewater.

    PubMed

    Telgmann, Lena; Wehe, Christoph A; Birka, Marvin; Künnemeyer, Jens; Nowak, Sascha; Sperling, Michael; Karst, Uwe

    2012-11-06

    The fate of Gadolinium (Gd)-based contrast agents for magnetic resonance imaging (MRI) during sewage treatment was investigated. The total concentration of Gd in influent and effluent 2 and 24 h composite samples was determined by means of isotope dilution analysis. The balancing of Gd input and output of a sewage plant over seven days indicated that approximately 10% of the Gd is removed during treatment. Batch experiments simulating the aeration tank of a sewage treatment plant confirmed the Gd complex removal during activated sludge treatment. For speciation analysis of the Gd complexes in wastewater samples, high performance liquid chromatography (HPLC) was hyphenated to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). Separation of the five predominantly used contrast agents was carried out on a new hydrophilic interaction liquid chromatography stationary phase in less than 15 min. A limit of detection (LOD) of 0.13 μg/L and a limit of quantification of 0.43 μg/L could be achieved for the Gd chelates without having to apply enrichment techniques. Speciation analysis of the 24 h composite samples revealed that 80% of the Gd complexes are present as Gd-BT-DO3A in the sampled treatment plant. The day-of-week dependent variation of the complex load followed the variation of the total Gd load, indicating a similar behavior. The analysis of sewage sludge did not prove the presence of anthropogenic Gd. However, in the effluent of the chamber filter press, which was used for sludge dewatering, two of the contrast agents and three other unknown Gd species were observed. This indicates that species transformation took place during anaerobic sludge treatment.

  8. Investigating the stability of gadolinium based contrast agents towards UV radiation.

    PubMed

    Birka, Marvin; Roscher, Jörg; Holtkamp, Michael; Sperling, Michael; Karst, Uwe

    2016-03-15

    Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed.

  9. Hepatic Gadolinium Deposition and Reversibility after Contrast Agent-enhanced MR Imaging of Pediatric Hematopoietic Stem Cell Transplant Recipients.

    PubMed

    Maximova, Natalia; Gregori, Massimo; Zennaro, Floriana; Sonzogni, Aurelio; Simeone, Roberto; Zanon, Davide

    2016-11-01

    Purpose To determine if hepatic gadolinium deposition occurs in pediatric patients with iron overload but normal renal and hepatic function who undergo gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance (MR) imaging. Materials and Methods Design and execution of this study was approved by the Ethical Committee of Institute for Research in Maternal and Child Health Burlo Garofolo of Trieste (reference no. 1105/2015). Because of the retrospective nature of the study, the requirement to obtain informed consent was waived. Twenty-one recipients of allogeneic hematopoietic stem cell transplants who underwent GBCA-enhanced MR imaging for suspected infection or relapse followed by liver biopsy comprised the study group. The number of GBCA-enhanced MR examinations and cumulative gadolinium dose for each patient was analyzed by comparing liver histologic analysis and iron and gadolinium liver concentration (GLC). Eight patients had siderosis and underwent chelation therapy. The study group was compared with four control patients who were never exposed to GBCA. Statistical analysis was performed with Spearman rank coefficient for correlation. Results All 21 patients had positive correlations between GLC and total GBCA dose (r = 0.4486; P < .05) and between GLC and liver iron concentration (r = 0.56; P < .05). Patients who underwent deferoxamine therapy had a significant reduction of GLC (from 0.64 μg/g ± 0.29 to 0.20 μg/g ± 0.17 [standard deviation]; P < .05). Conclusion In the presence of siderosis, a transmetallation mechanism may be set off between ferric ion and gadoterate meglumine. Deferoxamine appears capable of binding to gadolinium ion. Further studies of the safety of GBCAs in severe siderosis are needed. Chelation should be considered in patients with iron overload and a history of GBCA exposure. (©) RSNA, 2016.

  10. Application of extracellular gadolinium-based MRI contrast agents and the risk of nephrogenic systemic fibrosis.

    PubMed

    Heverhagen, J T; Krombach, G A; Gizewski, E

    2014-07-01

    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.

  11. Arterial double-contrast dual-energy MDCT: in-vivo rabbit atherosclerosis with iodinated nanoparticles and gadolinium agents

    NASA Astrophysics Data System (ADS)

    Carmi, Raz; Kafri, Galit; Altman, Ami; Goshen, Liran; Planer, David; Sosna, Jacob

    2010-03-01

    An in-vivo feasibility study of potentially improved atherosclerosis CT imaging is presented. By administration of two different contrast agents to rabbits with induced atherosclerotic plaques we aim at identifying both soft plaque and vessel lumen simultaneously. Initial injection of iodinated nanoparticle (INP) contrast agent (N1177 - Nanoscan Imaging), two to four hours before scan, leads to its later accumulation in macrophage-rich soft plaque, while a second gadolinium contrast agent (Magnevist) injected immediately prior to the scan blends with the aortic blood. The distinction between the two agents in a single scan is achieved with a double-layer dual-energy MDCT (Philips Healthcare) following material separation analysis using the reconstructed images of the different x-ray spectra. A single contrast agent injection scan, where only INP was injected two hours prior to the scan, was compared to a double-contrast scan taken four hours after INP injection and immediately after gadolinium injection. On the single contrast agent scan we observed along the aorta walls, localized iodine accumulation which can point on INP uptake by atherosclerotic plaque. In the double-contrast scan the gadolinium contributes a clearer depiction of the vessel lumen in addition to the lasting INP presence. The material separation shows a good correlation to the pathologies inferred from the conventional CT images of the two different scans while performing only a single scan prevents miss-registration problems and reduces radiation dose. These results suggest that a double-contrast dual-energy CT may be used for advanced clinical diagnostic applications.

  12. Stimuli-Responsive Biodegradable Hyperbranched Polymer-Gadolinium Conjugates as Efficient and Biocompatible Nanoscale Magnetic Resonance Imaging Contrast Agents.

    PubMed

    Sun, Ling; Li, Xue; Wei, Xiaoli; Luo, Qiang; Guan, Pujun; Wu, Min; Zhu, Hongyan; Luo, Kui; Gong, Qiyong

    2016-04-27

    The efficacy and biocompatibility of nanoscale magnetic resonance imaging (MRI) contrast agents depend on optimal molecular structures and compositions. Gadolinium [Gd(III)] based dendritic macromolecules with well-defined and tunable nanoscale sizes are excellent candidates as multivalent MRI contrast agents. Here, we propose a novel alternate preparation of biodegradable hyperbranched polymer-gadolinium conjugates via a simple strategy and report potentially efficient and biocompatible nanoscale MRI contrast agents for cancer diagnosis. The enzyme-responsive hyperbranched poly(oligo-(ethylene glycol) methacrylate)-gadolinium conjugate (HB-POEGMA-Gd) was prepared via one-step reversible addition-fragmentation chain transfer (RAFT) polymerization and Gd(III) chelating, and the cRGDyK functionalized polymer (HB-POEGMA-cRGD-Gd) was obtained via click chemistry. By using an enzyme similar to lysosomal cathepsin B, hyperbranched conjugates of high molecular weights (MW) (180 and 210 kDa) and nanoscale sizes (38 and 42 nm) were degraded into low MW (25 and 30 kDa) and smaller products (4.8 and 5.2 nm) below the renal threshold. Conjugate-based nanoscale systems had three-fold more T1 relaxivity compared to clinical agent diethylenediaminepentaacetic acid (DTPA)-Gd. Animal studies with the nanoscale system offered greater tumor accumulation and enhanced signal intensity (SI) in mouse U87 tumors of which the greatest activity was conferred by the cRGDyK moiety functionalized hyperbranched conjugate. In vitro cytotoxicity, hemocompatibility and in vivo toxicity studies confirmed no adverse events. This design strategy for multifunctional Gd(III)-labeled biodegradable dendritic macromolecules may have significant potential as future efficient, biocompatible polymeric nanoscale MRI diagnostic contrast agents for cancer.

  13. Biologically-compatible gadolinium(at)(carbon nanostructures) as advanced contrast agents for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Sitharaman, Balaji

    2005-11-01

    Paramagnetic gadolinium-based carbon nanostructures are introduced as a new paradigm in high-performance magnetic resonance imaging (MRI) contrast agent (CA) design. Two Gd C60-based nanomaterials, Gd C60 [C(COOH)2]10 and Gd C60(OH)x are shown to have MRI efficacies (relaxivities) 5 to 20 times larger than any current Gd3+-based CA in clinical use. The first detailed and systematic physicochemical characterization was performed on these materials using the same experimental techniques usually applied to traditional Gd 3+-based CAs. Water-proton relaxivities were measured for the first time on these materials, as a function of magnetic field (5 x 10-4--9.4 T) to elucidate the different interaction mechanisms and dynamic processes influencing the relaxation behavior. These studies attribute the observed enhanced relaxivities completely to the "outer sphere" proton relaxation mechanism. These "outer sphere" relaxation effects are the largest reported for any Gd3+-based agent without inner-sphere water molecules. The proton relaxivities displayed a remarkable pH-dependency, increasing dramatically with decreasing pH (pH: 3--12). The increase in relaxivity resulted mainly from aggregation and subsequent three-order-of-magnitude increase in tauR, the rotational correlation time. Water-soluble fullerene materials (such as the neuroprotective fullerene drug, C3) readily cross cell membranes, suggesting an application for these gadofullerenes as the first intracellular, as well as pH-responsive MRI CAs. Studies performed at 60 MHz in the presence of phosphate-buffered saline (PBS, mice serum pH: 7.4) to mimic physiological conditions demonstrated that the aggregates can be disrupted by addition of salts, leading to a decrease in relaxivity. Biological fluids present a high salt concentration and should strongly modify the behavior of any fullerenes/metallofullerene-based drug in vivo. Gd C60[C(COOH)2]10 also showed enhanced relaxivity (23% increase) in the presence of the

  14. Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study*

    PubMed Central

    da Silva, Yvana Lopes Pinheiro; Costa, Rita Zanlorensi Visneck; Pinho, Kátia Elisa Prus; Ferreira, Ricardo Rabello; Schuindt, Sueliton Miyamoto

    2015-01-01

    Objective To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality. Materials and Methods Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration. Results As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions. Conclusion Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography. PMID:25987746

  15. Spatially resolved quantification of gadolinium(III)-based magnetic resonance agents in tissue by MALDI imaging mass spectrometry after in vivo MRI.

    PubMed

    Aichler, Michaela; Huber, Katharina; Schilling, Franz; Lohöfer, Fabian; Kosanke, Katja; Meier, Reinhard; Rummeny, Ernst J; Walch, Axel; Wildgruber, Moritz

    2015-03-27

    Gadolinium(III)-based contrast agents improve the sensitivity and specificity of magnetic resonance imaging (MRI), especially when targeted contrast agents are applied. Because of nonlinear correlation between the contrast agent concentration in tissue and the MRI signal obtained in vivo, quantification of certain biological or pathophysiological processes by MRI remains a challenge. Up to now, no technology has been able to provide a spatially resolved quantification of MRI agents directly within the tissue, which would allow a more precise verification of in vivo imaging results. MALDI imaging mass spectrometry for spatially resolved in situ quantification of gadolinium(III) agents, in correlation to in vivo MRI, were evaluated. Enhanced kinetics of Gadofluorine M were determined dynamically over time in a mouse model of myocardial infarction. MALDI imaging was able to corroborate the in vivo imaging MRI signals and enabled in situ quantification of the gadolinium probe with high spatial resolution.

  16. Biodistribution of ultra small gadolinium-based nanoparticles as theranostic agent: application to brain tumors.

    PubMed

    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.

  17. Gadolinium-Induced Fibrosis.

    PubMed

    Todd, Derrick J; Kay, Jonathan

    2016-01-01

    Gadolinium-based contrast agents (GBCAs), once believed to be safe for patients with renal disease, have been strongly associated with nephrogenic systemic fibrosis (NSF), a severe systemic fibrosing disorder that predominantly afflicts individuals with advanced renal dysfunction. We provide a historical perspective on the appearance and disappearance of NSF, including its initial recognition as a discrete clinical entity, its association with GBCA exposure, and the data supporting a causative relationship between GBCA exposure and NSF. On the basis of this body of evidence, we propose that the name gadolinium-induced fibrosis (GIF) more accurately reflects the totality of knowledge regarding this disease. Use of high-risk GBCAs, such as formulated gadodiamide, should be avoided in patients with renal disease. Restriction of GBCA use in this population has almost completely eradicated new cases of this debilitating condition. Emerging antifibrotic therapies may be useful for patients who suffer from GIF.

  18. Vibrational dynamics of zero-field-splitting hamiltonian in gadolinium-based MRI contrast agents from ab initio molecular dynamics

    SciTech Connect

    Lasoroski, Aurélie; Vuilleumier, Rodolphe; Pollet, Rodolphe

    2014-07-07

    The electronic relaxation of gadolinium complexes used as MRI contrast agents was studied theoretically by following the short time evolution of zero-field-splitting parameters. The statistical analysis of ab initio molecular dynamics trajectories provided a clear separation between static and transient contributions to the zero-field-splitting. For the latter, the correlation time was estimated at approximately 0.1 ps. The influence of the ligand was also probed by replacing one pendant arm of our reference macrocyclic complex by a bulkier phosphonate arm. In contrast to the transient contribution, the static zero-field-splitting was significantly influenced by this substitution.

  19. Parallel Comparative Studies on Mouse Toxicity of Oxide Nanoparticle- and Gadolinium-Based T1 MRI Contrast Agents.

    PubMed

    Chen, Rui; Ling, Daishun; Zhao, Lin; Wang, Shuaifei; Liu, Ying; Bai, Ru; Baik, Seungmin; Zhao, Yuliang; Chen, Chunying; Hyeon, Taeghwan

    2015-12-22

    Magnetic resonance imaging (MRI) contrast agents with high relaxivity are highly desirable because they can significantly increase the accuracy of diagnosis. However, they can be potentially toxic to the patients. In this study, using a mouse model, we investigate the toxic effects and subsequent tissue damage induced by three T1 MRI contrast agents: gadopentetate dimeglumine injection (GDI), a clinically used gadolinium (Gd)-based contrast agent (GBCAs), and oxide nanoparticle (NP)-based contrast agents, extremely small-sized iron oxide NPs (ESIONs) and manganese oxide (MnO) NPs. Biodistribution, hematological and histopathological changes, inflammation, and the endoplasmic reticulum (ER) stress responses are evaluated for 24 h after intravenous injection. These thorough assessments of the toxic and stress responses of these agents provide a panoramic description of safety concerns and underlying mechanisms of the toxicity of contrast agents in the body. We demonstrate that ESIONs exhibit fewer adverse effects than the MnO NPs and the clinically used GDI GBCAs, providing useful information on future applications of ESIONs as potentially safe MRI contrast agents.

  20. Do Gadolinium-Based Contrast Agents Affect (18)F-FDG PET/CT Uptake in the Dentate Nucleus and the Globus Pallidus? A Pilot Study.

    PubMed

    Bauer, Kyle; Lathrum, Alaina; Raslan, Osama; Kelly, Patrick V; Zhou, Yihua; Hewing, Debra; Botkin, Crystal; Turner, James A; Osman, Medhat

    2017-03-01

    Gadolinium is toxic and to avoid its deposition in tissues, it must be chemically bonded with nonmetal ions to facilitate its excretion by the kidneys. High signal intensity in the dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted MR images has been both morphologically and pathologically linked to gadolinium-based contrast agent (GBCA) retention in the brain. The purpose of this study was to determine whether repeated administrations of GBCA would affect the uptake of (18)F-FDG in the DN and GP on PET/CT. Methods: Three hundred seventy-six patients who underwent both contrast-enhanced MR (CE MR) of the brain and PET/CT from January 2004 to October 2015 were identified. Patients with a history of brain irradiation or hepatic or renal disease were excluded. The SUVmax was measured in the DN and GP on the PET/CT scan in patients who had 3-6 successive CE MR brain studies. The SUVmax of the corresponding areas in the control group of patients who had not undergone previous CE MR and who had a normal, unenhanced MR finding of the brain was also measured. A Wilcoxon 2-sample test was used for statistical analysis. Results: Fifteen of 376 (4%) patients (mean age ± SD, 54 ± 18 y; 10 men and 5 women) were included in the subject group, and 15 patients (mean age ± SD, 36 ± 9 y; 11 men and 4 women) were included in the control group. The median DN SUVmax was significantly lower in the subject group than in the control group (5.4 vs. 6.4, respectively; P = 0.021). Similarly, the median GP SUVmax was significantly lower in the subject group than in the control group (8.8 vs. 12.1, respectively; P = 0.003). Conclusion: The median SUVmax in the DN and GP was 16% and 27% lower, respectively, in patients who received GBCAs than in those who had not received GBCAs, possibly related to gadolinium deposition in these areas.

  1. GADOLINIUM(Gd)-BASED and Ion Oxide Nanoparticle Contrast Agents for Pre-Clinical and Clinical Magnetic Resonance Imaging (mri) Research

    NASA Astrophysics Data System (ADS)

    Ng, Thian C.

    2012-06-01

    It is known that one strength of MRI is its excellent soft tissue discrimination. It naturally provides sufficient contrast between the structural differences of normal and pathological tissues, their spatial extent and progression. However, to further extend its applications and enhance even more contrast for clinical studies, various Gadolinium (Gd)-based contrast agents have been developed for different organs (brain strokes, cancer, cardio-MRI, etc). These Gd-based contrast agents are paramagnetic compounds that have strong T1-effect for enhancing the contrast between tissue types. Gd-contrast can also enhance magnetic resonance angiography (CE-MRA) for studying stenosis and for measuring perfusion, vascular susceptibility, interstitial space, etc. Another class of contrast agents makes use of ferrite iron oxide nanoparticles (including Superparamagnetic Ion Oxide (SPIO) and Ultrasmall Superparamagnetic Iron Oxide (USPIO)). These nanoparticles have superior magnetic susceptibility effect and produce a drop in signal, namely in T2*-weighted images, useful for the determination of lymph nodes metastases, angiogenesis and arteriosclerosis plaques.

  2. Gd(DOTAlaP): Exploring the Boundaries of Fast Water Exchange in Gadolinium-Based Magnetic Resonance Imaging Contrast Agents

    PubMed Central

    2015-01-01

    Here, we describe the synthesis of the single amino acid chelator DOTAlaP and four of its derivatives. The corresponding gadolinium(III) complexes were investigated for their kinetic inertness, relaxometric properties at a range of fields and temperatures, water exchange rate, and interaction with human serum albumin (HSA). Derivatives with one inner-sphere water (q = 1) were determined to have a mean water residency time between 8 and 6 ns in phoshate-buffered saline at 37 °C. The corresponding europium complexes were also formed and used to obtain information on the hydration number of the corresponding coordination complexes. Two complexes capable of binding HSA were also synthesized, of which one, Gd(5b), contains no inner-sphere water, while the other derivative, Gd(4b), is a mixture of ca. 15% q =1 and 85% q = 0. In the presence of HSA, the latter displayed a very short mean water residency time (τM310 = 2.4 ns) and enhanced relaxivity at intermediate and high fields. The kinetic inertness of Gd(4b) with respect to complex dissociation was decreased compared to its DOTAla analogue but still 100-fold more inert than [Gd(BOPTA)(H2O)]2–. Magnetic resonance imaging in mice showed that Gd(4b) was able to provide 38% better vessel to muscle contrast compared to the clinically used HSA binding agent MS-325. PMID:24922178

  3. Gadolinium oxysulfide nanoparticles as multimodal imaging agents for T2-weighted MR, X-ray tomography and photoluminescence

    NASA Astrophysics Data System (ADS)

    Osseni, Sèmiyou. A.; Lechevallier, Sévérine; Verelst, Marc; Perriat, Pascal; Dexpert-Ghys, Jeannette; Neumeyer, David; Garcia, Robin; Mayer, Florian; Djanashvili, Kristina; Peters, Joop A.; Magdeleine, Eddy; Gros-Dagnac, Hélène; Celsis, Pierre; Mauricot, Robert

    2013-12-01

    We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under excitation in the NUV (365 nm). They are not cytotoxic for living cells up to 100 μg mL-1. Consequently, they are well adapted for in vitro imaging on cell cultures. Gd2O2S:Eu3+ NPs also show strong transverse relaxivity and strong X-ray absorption allowing their use as contrast agents for T2-weighted MRI and X-ray tomography. Our study shows that Gd2O2S:Eu3+ NPs are considerably better than commercial Ferumoxtran-10 NPs as negative contrast agents for MRI. Upconversion emission of Gd2O2S:Er; Yb (1; 8%) NPs under infrared excitation (λex = 980 nm) shows mainly red emission (~650-680 nm). Consequently, they are more specifically designed for in vivo deep fluorescence imaging, because both excitation and emission are located inside the ``transparency window'' of biological tissues (650-1200 nm). Magnetic relaxivity and X-ray absorption behaviors of Gd2O2S:Er; Yb NPs are almost similar to Gd2O2S:Eu3+ NPs.We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under

  4. Preclinical animal acute toxicity studies of new developed MRI contrast agent based on gadolinium

    NASA Astrophysics Data System (ADS)

    Nam, I. F.; Zhuk, V. V.

    2015-04-01

    Acute toxicity test of new developed MRI contrast agent based on disodium salt of gadopentetic acid complex were carried out on Mus musculus and Sprague Dawley rats according to guidelines of preclinical studies [1]. Groups of six animals each were selected for experiment. Death and clinical symptoms of animals were recorded during 14 days. As a result the maximum tolerated dose (MTD) for female mice is 2.8 mM/kg of body weight, male mice - 1.4 mM/kg, female rats - 2.8 mM/kg, male rats - 5.6 mM/kg of body weight. No Observed Adverse Effect Dose (NOAEL) for female mice is 1.4 mM/kg, male mice - 0.7 mM/kg, male and female rats - 0.7 mM/kg. According to experimental data new developed MRI contrast agent based on Gd-DTPA complex is low-toxic.

  5. Highly relaxing gadolinium based MRI contrast agents responsive to Mg2+ sensing.

    PubMed

    Abada, Sabah; Lecointre, Alexandre; Elhabiri, Mourad; Esteban-Gómez, David; Platas-Iglesias, Carlos; Tallec, Gaylord; Mazzanti, Marinella; Charbonnière, Loïc J

    2012-04-28

    A Gd complex based on a polyphosphonated pyridyl ligand shows a very high stability in aqueous solution (log K(EuL) = 25.7), a high relaxivity (8.5 mM(-1) s(-1) at 25 °C and 20 MHz) and a marked and selective relaxivity enhancement (37%) in the presence of Mg(2+), opening interesting perspectives for the design of cation responsive contrast agents.

  6. Europium-doped gadolinium sulfide nanoparticles as a dual-mode imaging agent for T1-weighted MR and photoluminescence imaging.

    PubMed

    Jung, Jongjin; Kim, Mi Ae; Cho, Jee-Hyun; Lee, Seung Jae; Yang, Ilseung; Cho, Janggeun; Kim, Seong Keun; Lee, Chulhyun; Park, Joung Kyu

    2012-08-01

    We present a facile synthesis of europium-doped gadolinium sulfide (GdS:Eu(3+)) opto-magnetic nanoparticles (NPs) via sonochemistry. Their photoluminescence and strong paramagnetic properties enable these NPs to be utilized as an in vitro cell imaging and in vivo T(1)-weighted MR imaging probe. The GdS:Eu(3+) NPs have a prominent longitudinal (r(1)) relaxivity value, which is a critical parameter for T(1)-weighted MR imaging. Here, we showed not only their strong positive contrast effect to blood vessels and organs of mice, but also blood half-life and biodistribution including clearance from organs, in order to assess the GdS:Eu(3+) NPs as a competent nanocrystal-based T(1) contrast agent. We further showed confocal images of breast cancer cells containing GdS:Eu(3+) NPs to evaluate as a photoluminescence probe. Dual-mode imaging capability obtained from the GdS:Eu(3+) NPs will allow target-oriented cellular imaging as well as the resulting disease-specific MR imaging.

  7. Synthesis and biological evaluation of a class of mitochondrially-targeted gadolinium(III) agents.

    PubMed

    Morrison, Daniel E; Aitken, Jade B; de Jonge, Martin D; Issa, Fatiah; Harris, Hugh H; Rendina, Louis M

    2014-12-08

    A structure-activity relationship study of a library of novel bifunctional Gd(III) complexes covalently linked to arylphosphonium cations is reported. Such complexes have been designed for potential application in binary cancer therapies such as neutron capture therapy and photon activation therapy. A positive correlation was found between lipophilicity and cytotoxicity of the complexes. Mitochondria uptake was determined by means of inductively coupled plasma mass spectrometry (ICP-MS), and Gd uptake was determined by means of quantification using synchrotron X-ray fluorescence (XRF) imaging. A negative correlation between lipophilicity and tumour selectivity of the Gd(III) complexes was demonstrated. This study highlights the delicate balance required to minimise in vitro cytotoxicity and optimise in vitro tumour selectivity and mitochondrial localisation for this new class of mitochondrially-targeted binary therapy agents. We also report the highest in vitro tumour selectivity for any Gd agent reported to date, with a T/N (tumour/normal cell) ratio of up to 23.5±6.6.

  8. Effect of hepatocyte-specific gadolinium-based contrast agents on hepatic fat-fraction and R2(⁎).

    PubMed

    Hernando, Diego; Wells, Shane A; Vigen, Karl K; Reeder, Scott B

    2015-01-01

    The purpose of this work was to investigate the effect of a hepatocyte-specific gadolinium based contrast agent (GBCA) on quantitative hepatic fat-fraction (FF) and R2* measurements. Fifty patients were imaged at 1.5T, using chemical-shift encoded water-fat MRI with low (5°) and high (15°) flip angles (FA), both before and after administration of a hepatocyte-specific GBCA (gadoxetic acid). Low and high FA, pre- and post-contrast FF and R2* values were measured for each subject. Available serum laboratory studies related to liver disease were also recorded. Linear regression and Bland-Altman analysis were performed to compare measurements. Hepatic FF was unaffected by GBCA at low FA (slope=1.02±0.02, p=0.32). FF was overestimated at high FA pre-contrast (slope=1.33±0.03, p<10(-10)), but underestimated post-contrast (slope=0.81±0.02, p<10(-10)). Hepatic R2* was unaffected by FA (mean difference±95% CI pre-contrast:2.2±4.9s(-1), post-contrast:2.8±3.6s(-1)), but increased post-contrast in patients with total bilirubin <2.5mg/dL (ΔR2*=13.4±12.7s(-1)). Regression analysis of serum values demonstrated a correlation of post-contrast change in R2* with total bilirubin (p<0.01) and model for end-stage liver disease (MELD) score (p≈0.01). In conclusion, GBCA has no effect on hepatic FF at low FA due to a lack of T1-weighting, potentially allowing flexibility for FF imaging with hepatobiliary imaging protocols. Hepatic R2* increased significantly after GBCA administration, particularly in the biliary tree. Therefore, R2* maps should be obtained prior to contrast administration.

  9. Terbium-doped gadolinium oxide nanoparticles prepared by laser ablation in liquid for use as a fluorescence and magnetic resonance imaging dual-modal contrast agent.

    PubMed

    Chen, Fei; Chen, Min; Yang, Chuan; Liu, Jun; Luo, Ningqi; Yang, Guowei; Chen, Dihu; Li, Li

    2015-01-14

    Dual-modal lanthanide-doped gadolinium nanoparticles (NPs), which exhibit an excellent magnetic resonance imaging (MRI) spatial resolution and high fluorescence imaging (FI) sensitivity, have attracted tremendous attention in biotechnology and nanomedicine applications. In this paper, terbium (Tb) ion doped gadolinium oxide (Gd2O3:Tb) NPs with varied Tb concentrations were synthesized by a laser ablation in liquid (LAL) method. The characterization of the structure, morphology, and composition shows that these NPs are spherical with excellent crystallinity. The effects of Tb ion concentration on the visible green fluorescence and longitudinal relaxivity were investigated, indicating that the fluorescence properties were significantly influenced by the Tb ion concentration, but all samples were still efficient T1-weighted contrast agents. Furthermore, the optimum Tb doping concentration was determined to be 1%. The cell viability, cellular fluorescence imaging and in vivo MRI of this dual-modal nano-probe were studied, with the results revealing that the Gd2O3:Tb NPs did not have a significant cytotoxic effect, making them good candidates for use as a dual-modal contrast agent for MRI and fluorescence imaging.

  10. T1-T2 Dual-modal MRI contrast agents based on superparamagnetic iron oxide nanoparticles with surface attached gadolinium complexes

    NASA Astrophysics Data System (ADS)

    Szpak, Agnieszka; Fiejdasz, Sylwia; Prendota, Witold; Strączek, Tomasz; Kapusta, Czesław; Szmyd, Janusz; Nowakowska, Maria; Zapotoczny, Szczepan

    2014-11-01

    Dual-mode MRI contrast agents consisting of superparamagnetic iron oxide nanoparticle (SPION) cores and gadolinium ions associated with the ionic chitosan protecting layer were synthesized and studied. Gadolinium ions were introduced into the coating layer via direct complex formation on the nanoparticles surface, covalent attachment or electrostatically driven deposition of the preformed Gd complex. The modified SPIONs having hydrodynamic diameters ca. 100 nm form stable, well-defined dispersions in water and have excellent magnetic properties. Physiochemical properties of those new materials were characterized using e.g., FTIR spectroscopy, dynamic light scattering, X-ray fluorescence, TEM, and vibrating sample magnetometry. They behave as superparamagnetics and shorten both T1 and T2 proton relaxation times, thus influencing both r1 and r2 relaxivity values that reach 53.7 and 375.5 mM-1 s-1, respectively, at 15 MHz. The obtained materials can be considered as highly effective contrast agents for low-field MRI, particularly useful at permanent magnet-based scanners.

  11. Gadolinium Deposition in Humans: When Did We Learn That Gadolinium Was Deposited In Vivo?

    PubMed

    Huckle, James E; Altun, Ersan; Jay, Michael; Semelka, Richard C

    2016-04-01

    Recently, there have been numerous major peer-reviewed publications reporting deposition of gadolinium in the dentate nucleus and globus pallidus in subjects with normal renal function. This review takes a retrospective look back through the development of gadolinium-based contrast agents to describe the historical evidence of gadolinium deposition in vivo and shows that deposition in the basal ganglia should come as no surprise. Evidence for gadolinium deposition in both animal models and human patients is described. Stability differences among gadolinium contrast agents have long been recognized in vitro, and deposition of gadolinium in tissues has been described in animal models since at least 1984. The first major study that showed deposition in humans appeared in 1998 regarding patients with renal failure and in 2004 in patients with normal renal function. The historical literature indicates that gadolinium retention in healthy patients is occurring, although the clinical consequences of deposition remain unknown.

  12. Effect of ionic interaction between a hyperpolarized magnetic resonance chemical probe and a gadolinium contrast agent for the hyperpolarized lifetime after dissolution

    NASA Astrophysics Data System (ADS)

    Takakusagi, Yoichi; Inoue, Kaori; Naganuma, Tatsuya; Hyodo, Fuminori; Ichikawa, Kazuhiro

    2016-09-01

    In hyperpolarization of 13C-enriched magnetic resonance chemical probes in the solid-state, a trace amount of gadolinium (Gd) contrast agent can be used to maximize polarization of the 13C nuclear spins. Here, we report systematic measurement of the spin-lattice relaxation time (T1) and enhancement level of 13C-enriched chemical probes in the presence of various Gd contrast agents in the liquid-state after dissolution. Using two different 13C probes having opposite electric charges at neutral pH, we clearly show the T1 of hyperpolarized 13C was barely affected by the use of a Gd complex that displays repulsive interaction with the 13C probe in solution, whilst T1 was drastically shortened when there was ionic attraction between probe and complex.

  13. Evaluation of absorbed dose in Gadolinium neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Abdullaeva, Gayane; Djuraeva, Gulnara; Kim, Andrey; Koblik, Yuriy; Kulabdullaev, Gairatulla; Rakhmonov, Turdimukhammad; Saytjanov, Shavkat

    2015-02-01

    Gadolinium neutron capture therapy (GdNCT) is used for treatment of radioresistant malignant tumors. The absorbed dose in GdNCT can be divided into four primary dose components: thermal neutron, fast neutron, photon and natural gadolinium doses. The most significant is the dose created by natural gadolinium. The amount of gadolinium at the irradiated region is changeable and depends on the gadolinium delivery agent and on the structure of the location where the agent is injected. To de- fine the time dependence of the gadolinium concentration ρ(t) in the irradiated region the pharmacokinetics of gadolinium delivery agent (Magnevist) was studied at intratumoral injection in mice and intramuscular injection in rats. A polynomial approximation was applied to the experimental data and the influence of ρ(t) on the relative change of the absorbed dose of gadolinium was studied.

  14. Gadolinium- and manganite-based contrast agents with fluorescent probes for both magnetic resonance and fluorescence imaging of pancreatic islets: a comparative study.

    PubMed

    Berkova, Zuzana; Jirak, Daniel; Zacharovova, Klara; Lukes, Ivan; Kotkova, Zuzana; Kotek, Jan; Kacenka, Michal; Kaman, Ondrej; Rehor, Ivan; Hajek, Milan; Saudek, Frantisek

    2013-04-01

    Three magnetic resonance (MR)/fluorescence imaging probes were tested for visualization, cellular distribution, and survival of labeled pancreatic islets in vitro and following transplantation. As T(1) contrast agents (CAs), gadolinium(III) complexes linked to β-cyclodextrin (Gd-F-βCD) or bound to titanium dioxide (TiO2 @RhdGd) were tested. As a T(2) CA, perovskite manganite nanoparticles (LSMO@siF@si) were examined. Fluorescein or rhodamine was incorporated as a fluorescent marker in all probes. Islets labeled with gadolinium(III) CAs were visible as hyperintense spots on MR in vitro, but detection in vivo was inconclusive. Islets labeled with LSMO@siF@si CA were clearly visible as hypointense spots or areas on MR scans in vitro as well as in vivo. All CAs were detected inside the islet cells by fluorescence. Although the vitality and function of the labeled islets was not impaired by any of the tested CAs, results indicate that LSMO@siF@si CA is a superior marker for islet labeling, as it provides better contrast enhancement within a shorter scan time.

  15. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for... will appoint or cause to be appointed agent(s) to perform functions necessary to market and service... Fiscal Agent to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the...

  16. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial... financial markets to determine those factors that will minimize or reduce the cost of funding Debentures...) Agents. SBA may appoint or cause to be appointed agent(s) to perform functions necessary to market...

  17. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial... financial markets to determine those factors that will minimize or reduce the cost of funding Debentures...) Agents. SBA may appoint or cause to be appointed agent(s) to perform functions necessary to market...

  18. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for... will appoint or cause to be appointed agent(s) to perform functions necessary to market and service... Fiscal Agent to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the...

  19. Gadolinium deposition in nephrogenic fibrosing dermopathy.

    PubMed

    Boyd, Alan S; Zic, John A; Abraham, Jerrold L

    2007-01-01

    There is growing recognition of the association between the use of gadolinium-containing radiocontrast agents for magnetic resonance imaging and the serious dermal and systemic disease nephrogenic fibrosing dermopathy/nephrogenic systemic fibrosis (NFD/NSF). The pathogenesis of this entity remains unclear; however, our recent observations suggest a likely mechanism for the initial dermal manifestations of this gadolinium toxicity.

  20. Poly(acrylic acid) Bridged Gadolinium Metal-Organic Framework-Gold Nanoparticle Composites as Contrast Agents for Computed Tomography and Magnetic Resonance Bimodal Imaging

    PubMed Central

    Tian, Chixia; Zhu, Liping; Lin, Feng; Boyes, Stephen G.

    2015-01-01

    Imaging contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) have received significant attention in the development of techniques for early-stage cancer diagnosis. Gadolinium (Gd) (III), which has seven unpaired electrons and a large magnetic moment, can dramatically influence the water proton relaxation and hence exhibits excellent MRI contrast. On the other hand, gold (Au), which has a high atomic number and high x-ray attenuation coefficient, is an ideal contrast agent candidate for x-ray based CT imaging. Gd metal organic framework (MOF) nanoparticles with tunable size, high Gd (III) loading and multivalency can potentially overcome the limitations of clinically utilized Gd chelate contrast agents. In this work, we report for the first time the integration of GdMOF nanoparticles with gold nanoparticles (AuNPs) for the preparation of a MRI/CT bimodal imaging agent. Highly stable hybrid GdMOF/AuNPs composites have been prepared by using poly(acrylic acid) as a bridge between the GdMOF nanoparticles and AuNPs. The hybrid nanocomposites were then evaluated in MRI and CT imaging. The results revealed high longitudinal relaxivity in MRI and excellent CT imaging performance. Therefore, these GdMOF/AuNPs hybrid nanocomposites potentially provide a new platform for the development of multi-modal imaging probes. PMID:26147906

  1. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial markets..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs... or cause to be appointed agent(s) to perform functions necessary to market and service Debentures...

  2. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial markets..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs... or cause to be appointed agent(s) to perform functions necessary to market and service Debentures...

  3. Magnetic resonance imaging of the central nervous system in children with a new nonionic gadolinium contrast agent--gadoteridol injection (ProHance).

    PubMed Central

    Byrd, S. E.; Darling, C. F.; Wilczynski, M. A.

    1993-01-01

    This article reports the results of clinical testing in pediatric patients of a new contrast agent, gadoteridol injection (ProHance), developed by Squibb Diagnostic as a nonionic gadolinium agent for use in magnetic resonance imaging (MRI). Thirteen children (four girls and nine boys) ranging in age from 10 to 18 years were enrolled in the study. The children had MR studies of the brain and/or spine with T1-weighted, T2-weighted, and postgadoteridol injection T1-weighted sequences. Five children had primary brain or spine neoplasms, three children had metastatic disease to the central nervous system, one child had a recurrent brain neoplasm and spinal canal metastasis, one child had an arteriovenous malformation, and two children were normal on the MRI studies. No minor or major reactions to gadoteridol injection developed in the 13 patients. Gadoteridol injection provided excellent delineation and enhancement of the arteriovenous malformation and all of the primary and secondary neoplasms of the central nervous system except for one case of a grade 1 glioma of the midbrain. Gadoteridol injection is a safe and excellent contrast agent for use in MRI. Images Figures 1-5 Figures 6-10 PMID:8496990

  4. Global and Regional Brain Assessment with Quantitative MR Imaging in Patients with Prior Exposure to Linear Gadolinium-based Contrast Agents.

    PubMed

    Kuno, Hirofumi; Jara, Hernán; Buch, Karen; Qureshi, Muhammad Mustafa; Chapman, Margaret N; Sakai, Osamu

    2017-04-01

    Purpose To assess the association of global and regional brain relaxation times in patients with prior exposure to linear gadolinium-based contrast agents (GBCAs). Materials and Methods The institutional review board approved this cross-sectional study. Thirty-five patients (nine who had received GBCA gadopentetate dimeglumine injections previously [one to eight times] and 26 patients who did not) who underwent brain magnetic resonance (MR) imaging with a mixed fast spin-echo pulse sequence were assessed. The whole brain was segmented according to white and gray matter by using a dual-clustering algorithm. In addition, regions of interest were measured in the globus pallidus, dentate nucleus, thalamus, and pons. The Mann-Whitney U test was used to assess the difference between groups. Multiple regression analysis was performed to assess the association of T1 and T2 with prior GBCA exposure. Results T1 values of gray matter were significantly shorter for patients with than for patients without prior GBCA exposure (P = .022). T1 of the gray matter of the whole brain (P < .001), globus pallidus (P = .002), dentate nucleus (P = .046), and thalamus (P = .026) and T2 of the whole brain (P = .004), dentate nucleus (P = .023), and thalamus (P = .002) showed a significant correlation with the accumulated dose of previous GBCA administration. There was no significant correlation between T1 and the accumulated dose of previous GBCA injections in the white matter (P = .187). Conclusion Global and regional quantitative assessments of T1 and T2 demonstrated an association with prior GBCA exposure, especially for gray matter structures. The results of this study confirm previous research findings that there is gadolinium deposition in wider distribution throughout the brain. (©) RSNA, 2016 Online supplemental material is available for this article.

  5. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs (Leverage) Funding Leverage by Use of Guaranteed Trust Certificates (âtcsâ) § 4290.1620 Functions of agents... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial...

  6. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for Licensees (Leverage) Funding Leverage by Use of Sba-Guaranteed Trust Certificates (âtcsâ) § 107.1620... Fiscal Agent to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the...

  7. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs (Leverage) Funding Leverage by Use of Guaranteed Trust Certificates (âtcsâ) § 4290.1620 Functions of agents... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial...

  8. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for Licensees (Leverage) Funding Leverage by Use of Sba-Guaranteed Trust Certificates (âtcsâ) § 107.1620... Fiscal Agent to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the...

  9. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for Licensees (Leverage) Funding Leverage by Use of Sba-Guaranteed Trust Certificates (âtcsâ) § 107.1620... Fiscal Agent to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the...

  10. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs (Leverage) Funding Leverage by Use of Guaranteed Trust Certificates (âtcsâ) § 4290.1620 Functions of agents... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial...

  11. Multimodal Magnetic Resonance and Near-Infrared-Fluorescent Imaging of Intraperitoneal Ovarian Cancer Using a Dual-Mode-Dual-Gadolinium Liposomal Contrast Agent

    PubMed Central

    Ravoori, M. K.; Singh, S.; Bhavane, R.; Sood, A. K.; Anvari, B.; Bankson, J.; Annapragada, A.; Kundra, V.

    2016-01-01

    The degree of tumor removal at surgery is a major factor in predicting outcome for ovarian cancer. A single multimodality agent that can be used with magnetic resonance (MR) for staging and pre-surgical planning, and with optical imaging to aid surgical removal of tumors, would present a new paradigm for ovarian cancer. We assessed whether a dual-mode, dual-Gadolinium (DM-Dual-Gd-ICG) contrast agent can be used to visualize ovarian tumors in the peritoneal cavity by multimodal MR and near infra-red imaging (NIR). Intraperitoneal ovarian tumors (Hey-A8 or OVCAR3) in mice enhanced on MR two days after intravenous DM-Dual Gd-ICG injection compared to controls (SNR, CNR, p < 0.05, n = 6). As seen on open abdomen and excised tumors views and confirmed by optical radiant efficiency measurement, Hey-A8 or OVCAR3 tumors from animals injected with DM-Dual Gd-ICG had increased fluorescence (p < 0.05, n = 6). This suggests clinical potential to localize ovarian tumors by MR for staging and surgical planning, and, by NIR at surgery for resection. PMID:28004770

  12. Albumin binding, relaxivity, and water exchange kinetics of the diastereoisomers of MS-325, a gadolinium(III)-based magnetic resonance angiography contrast agent.

    PubMed

    Caravan, Peter; Parigi, Giacomo; Chasse, Jaclyn M; Cloutier, Normand J; Ellison, Jeffrey J; Lauffer, Randall B; Luchinat, Claudio; McDermid, Sarah A; Spiller, Marga; McMurry, Thomas J

    2007-08-06

    The amphiphilic gadolinium complex MS-325 ((trisodium-{(2-(R)-[(4,4-diphenylcyclohexyl) phosphonooxymethyl] diethylenetriaminepentaacetato) (aquo)gadolinium(III)}) is a contrast agent for magnetic resonance angiography (MRA). MS-325 consists of two slowly interconverting diastereoisomers, A and B (65:35 ratio), which can be isolated at pH > 8.5 (TyeklAr, Z.; Dunham, S. U.; Midelfort, K.; Scott, D. M.; Sajiki, H.; Ong, K.; Lauffer, R. B.; Caravan, P.; McMurry, T. J. Inorg. Chem. 2007, 46, 6621-6631). MS-325 binds to human serum albumin (HSA) in plasma resulting in an extended plasma half-life, retention of the agent within the blood compartment, and an increased relaxation rate of water protons in plasma. Under physiological conditions (37 degrees C, pH 7.4, phosphate buffered saline (PBS), 4.5% HSA, 0.05 mM complex), there is no statistical difference in HSA affinity or relaxivity between the two isomers (A 88.6 +/- 0.6% bound, r1 = 42.0 +/- 1.0 mM(-1) s(-1) at 20 MHz; B 90.2 +/- 0.6% bound, r1 = 38.3 +/- 1.0 mM(-1) s(-1) at 20 MHz; errors represent 1 standard deviation). At lower temperatures, isomer A has a higher relaxivity than isomer B. The water exchange rates in the absence of HSA at 298 K, kA298 = 5.9 +/- 2.8 x 10(6) s(-1), kB298 = 3.2 +/- 1.8 x 10(6) s(-1), and heats of activation, DeltaHA = 56 +/- 8 kJ/mol, DeltaHB = 59 +/- 11 kJ/mol, were determined by variable-temperature 17O NMR at 7.05 T. Proton nuclear magnetic relaxation dispersion (NMRD) profiles were recorded over the frequency range of 0.01-50 MHz at 5, 15, 25, and 35 degrees C in a 4.5% HSA in PBS solution for each isomer (0.1 mM). Differences in the relaxivity in HSA between the two isomers could be attributed to the differing water exchange rates.

  13. A Theranostic Agent Combining a Two-Photon-Absorbing Photosensitizer for Photodynamic Therapy and a Gadolinium(III) Complex for MRI Detection.

    PubMed

    Schmitt, Julie; Heitz, Valérie; Sour, Angélique; Bolze, Frédéric; Kessler, Pascal; Flamigni, Lucia; Ventura, Barbara; Bonnet, Célia S; Tóth, Éva

    2016-02-18

    The convergent synthesis and characterization of a potential theranostic agent, [DPP-ZnP-GdDOTA](-), which combines a diketopyrrolopyrrole-porphyrin component DPP-ZnP as a two-photon photosensitizer for photodynamic therapy (PDT) with a gadolinium(III) DOTA complex as a magnetic resonance imaging probe, is presented. [DPP-ZnP-GdDOTA](-) has a remarkably high longitudinal water proton relaxivity (19.94 mm(-1)  s(-1) at 20 MHz and 25 °C) for a monohydrated molecular system of this size. The Nuclear Magnetic Relaxation Dispersion (NMRD) profile is characteristic of slow rotation, related to the extended and rigid aromatic units integrated in the molecule and to self-aggregation occurring in aqueous solution. The two-photon properties were examined and large two-photon absorption cross-sections around 1000 GM were determined between 910 and 940 nm in DCM with 1 % pyridine and in DMSO. Furthermore, the new conjugate was able to generate singlet oxygen, with quantum yield of 0.42 and 0.68 in DCM with 1 % pyridine and DMSO, respectively. Cellular studies were also performed. The [DPP-ZnP-GdDOTA](-) conjugate demonstrated low dark toxicity and was able to induce high one-photon and moderate two-photon phototoxicity on cancer cells.

  14. Solution and solid-state characterization of europium and gadolinium Schiff base complexes and assessment of their potential as contrast agents in magnetic resonance imaging

    SciTech Connect

    Smith, P.H.; Brainard, J.R.; Morris, D.E.; Jarvinen, G.D.; Ryan, R.R. )

    1989-09-13

    Two lanthanide Schiff base macrocyclic complexes, LnAM(OAc){sub 2}Cl{center dot}4H{sub 2}O (Ln = Eu, Gd; HAM - HexaAzaMacrocycle = C{sub 22}H{sub 26}N{sub 6}), have been characterized in view of the potential of the Gd complex as a magnetic resonance imaging (MRI) contrast agent. The relaxivity of GdHAM(OAc){sub 2}Cl was measured at 300 and 20 MHz and is as high as that for the gadolinium aquo ion. The number of coordinated waters, q, was measured by comparison of the luminescent lifetimes of EuHAM(OAc){sub 2}Cl in H{sub 2}O and D{sub 2}O and found to be between three and four. The complex GdHAM(OAc){sub 2}Cl{center dot}4H{sub 2}O was characterized by single-crystal X-ray diffraction. The complex crystallizes in space group P{bar 1} with Z = 2, a = 10.032 (2) {angstrom}, b = 12.765 (2) {angstrom}, c = 13.668 (3) {angstrom}, {alpha} = 69.190{degree} (9){degree}, {beta} = 72.405{degree} (9){degree}, and {gamma} = 74.07{degree} (1){degree}.

  15. EP-2104R: a fibrin-specific gadolinium-Based MRI contrast agent for detection of thrombus.

    PubMed

    Overoye-Chan, Kirsten; Koerner, Steffi; Looby, Richard J; Kolodziej, Andrew F; Zech, Stephan G; Deng, Qing; Chasse, Jaclyn M; McMurry, Thomas J; Caravan, Peter

    2008-05-07

    Thrombus (blood clot) is implicated in a number of life threatening diseases, e.g., heart attack, stroke, pulmonary embolism. EP-2104R is an MRI contrast agent designed to detect thrombus by binding to the protein fibrin, present in all thrombi. EP-2104R comprises an 11 amino acid peptide derivatized with 2 GdDOTA-like moieties at both the C- and N-terminus of the peptide (4 Gd in total). EP-2104R was synthesized by a mixture of solid phase and solution techniques. The La(III) analogue was characterized by and 1D and 2D NMR spectroscopy and was found to have the expected structure. EP-2104R was found to be significantly more inert to Gd(III) loss than commercial contrast agents. At the most extreme conditions tested (pH 3, 60 degrees C, 96 hrs), less than 10% of Gd was removed from EP-2104R by a challenge with a DTPA based ligand, while the commercial contrast agents equilibrated within minutes to hours. EP-2104R binds equally to two sites on human fibrin (Kd = 1.7 +/- 0.5 microM) and has a similar affinity to mouse, rat, rabbit, pig, and dog fibrin. EP-2104R has excellent specificity for fibrin over fibrinogen (over 100-fold) and for fibrin over serum albumin (over 1000-fold). The relaxivity of EP-2104R bound to fibrin at 37 degrees C and 1.4 T was 71.4 mM(-1) s(-1) per molecule of EP-2104R (17.4 per Gd), about 25 times higher than that of GdDOTA measured under the same conditions. Strong fibrin binding, fibrin selectivity, and high molecular relaxivity enable EP-2104R to detect blood clots in vivo.

  16. GADOLINIUM SOLUBILITY AND VOLATILITY DURING DWPF PROCESSING

    SciTech Connect

    Reboul, S

    2008-01-30

    Understanding of gadolinium behavior, as it relates to potential neutron poisoning applications at the DWPF, has increased over the past several years as process specific data have been generated. Of primary importance are phenomena related to gadolinium solubility and volatility, which introduce the potential for gadolinium to be separated from fissile materials during Chemical Process Cell (CPC) and Melter operations. Existing data indicate that gadolinium solubilities under moderately low pH conditions can vary over several orders of magnitude, depending on the quantities of other constituents that are present. With respect to sludge batching processes, the gadolinium solubility appears to be highly affected by iron. In cases where the mass ratio of Fe:Gd is 300 or more, the gadolinium solubility has been observed to be low, one milligram per liter or less. In contrast, when the ratio of Fe:Gd is 20 or less, the gadolinium solubility has been found to be relatively high, several thousands of milligrams per liter. For gadolinium to serve as an effective neutron poison in CPC operations, the solubility needs to be limited to approximately 100 mg/L. Unfortunately, the Fe:Gd ratio that corresponds to this solubility limit has not been identified. Existing data suggest gadolinium and plutonium are not volatile during melter operations. However, the data are subject to inherent uncertainties preventing definitive conclusions on this matter. In order to determine if gadolinium offers a practical means of poisoning waste in DWPF operations, generation of additional data is recommended. This includes: Gd solubility testing under conditions where the Fe:Gd ratio varies from 50 to 150; and Gd and Pu volatility studies tailored to quantifying high temperature partitioning. Additional tests focusing on crystal aging of Gd/Pu precipitates should be pursued if receipt of gadolinium-poisoned waste into the Tank Farm becomes routine.

  17. Intra-individual comparison of different gadolinium-based contrast agents in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging.

    PubMed

    Li, Ying; Liu, Gang; Lou, Xin; Chen, Zhiye; Ma, Lin

    2017-01-01

    This experiment aimed to compare the ionic (Gadodiamide, Gd-DTPA-BMA) and non-ionic (Gadopentetate dimeglumine, Gd-DTPA) gadolinium-based contrast agents (GBCA) in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A C6 glioma model was established in 12 Wistar rats, and magnetic resonance (MR) scans were performed six days after tumor implantation. Imaging was performed using a 3.0-T MR scanner with a 7-inch handmade circular coil. Pre-contrast T1 mapping and dynamic contrast-enhanced T1WI after a bolus injection (0.2 mL s(-1)) of GBCA at 0.4 mmol kg(-1) were performed. Each rat received two DCE-MRI scans, 24 h apart. The first and second scans were performed using Gd-DTPA-BMA and Gd-DTPA, respectively. Image data were processed using the Patlak model. Both K (trans) and V p maps were generated. Tumors were manually segmented on all 3D K (trans) and V p maps. Pixel counts and mean values were recorded for use in a paired t-test. Three radiologists independently performed the tumor segmentation and value calculation. The agreements from different observers were subjective to the intra-class correlation coefficient (ICC). Readers demonstrated that the pixel counts of tumors in K (trans) maps were higher with Gd-DTPA-BMA than with Gd-DTPA (P<0.001, all readers). Although the K (trans) values were higher with Gd-DTPA-BMA than with Gd-DTPA, there was no statistical significance (P>0.05, all readers). The pixel counts of tumors in V p maps, as well as V p values, showed no obvious difference between the two agents (P>0.05, all readers). Excellent interobserver measurement reproducibility and reliability were demonstrated in the ICC tests. The Gd-DTPA-BMA contrast agent had significantly higher pixel counts of glioma in the K (trans) maps, and an increased tendency for average K (trans) values, indicating that DCE-MRI with Gd-DTPA-BMA may be more suitable and sensitive for the evaluation of glioma.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy

    SciTech Connect

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

    2009-04-19

    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{sub 2}O{sub 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.

  20. Effects of Gadolinium-Based Contrast Agents on Thyroid Hormone Receptor Action and Thyroid Hormone-Induced Cerebellar Purkinje Cell Morphogenesis

    PubMed Central

    Ariyani, Winda; Iwasaki, Toshiharu; Miyazaki, Wataru; Khongorzul, Erdene; Nakajima, Takahito; Kameo, Satomi; Koyama, Hiroshi; Tsushima, Yoshito; Koibuchi, Noriyuki

    2016-01-01

    Gadolinium (Gd)-based contrast agents (GBCAs) are used in diagnostic imaging to enhance the quality of magnetic resonance imaging or angiography. After intravenous injection, GBCAs can accumulate in the brain. Thyroid hormones (THs) are critical for the development and functional maintenance of the central nervous system. TH actions in brain are mainly exerted through nuclear TH receptors (TRs). We examined the effects of GBCAs on TR-mediated transcription in CV-1 cells using transient transfection-based reporter assay and TH-mediated cerebellar Purkinje cell morphogenesis in primary culture. We also measured the cellular accumulation and viability of Gd after representative GBCA treatments in cultured CV-1 cells. Both linear (Gd-diethylene triamine pentaacetic acid-bis methyl acid, Gd-DTPA-BMA) and macrocyclic (Gd-tetraazacyclododecane tetraacetic acid, Gd-DOTA) GBCAs were accumulated without inducing cell death in CV-1 cells. By contrast, Gd chloride (GdCl3) treatment induced approximately 100 times higher Gd accumulation and significantly reduced the number of cells. Low doses of Gd-DTPA-BMA (10−8 to 10−6M) augmented TR-mediated transcription, but the transcription was suppressed at higher dose (10−5 to 10−4M), with decreased β-galactosidase activity indicating cellular toxicity. TR-mediated transcription was not altered by Gd-DOTA or GdCl3, but the latter induced a significant reduction in β-galactosidase activity at high doses, indicating cellular toxicity. In cerebellar cultures, the dendrite arborization of Purkinje cells induced by 10−9M T4 was augmented by low-dose Gd-DTPA-BMA (10−7M) but was suppressed by higher dose (10−5M). Such augmentation by low-dose Gd-DTPA-BMA was not observed with 10−9M T3, probably because of the greater dendrite arborization by T3; however, the arborization by T3 was suppressed by a higher dose of Gd-DTPA-BMA (10−5M) as seen in T4 treatment. The effect of Gd-DOTA on dendrite arborization was much weaker

  1. 28 CFR 552.25 - Use of less-than-lethal weapons, including chemical agents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Use of less-than-lethal weapons... Use of less-than-lethal weapons, including chemical agents. (a) The Warden may authorize the use of less-than-lethal weapons, including those containing chemical agents, only when the situation is...

  2. 28 CFR 552.25 - Use of less-than-lethal weapons, including chemical agents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Use of less-than-lethal weapons... Use of less-than-lethal weapons, including chemical agents. (a) The Warden may authorize the use of less-than-lethal weapons, including those containing chemical agents, only when the situation is...

  3. 28 CFR 552.25 - Use of less-than-lethal weapons, including chemical agents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Use of less-than-lethal weapons... Use of less-than-lethal weapons, including chemical agents. (a) The Warden may authorize the use of less-than-lethal weapons, including those containing chemical agents, only when the situation is...

  4. 28 CFR 552.25 - Use of less-than-lethal weapons, including chemical agents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Use of less-than-lethal weapons... Use of less-than-lethal weapons, including chemical agents. (a) The Warden may authorize the use of less-than-lethal weapons, including those containing chemical agents, only when the situation is...

  5. Signal Increase on Unenhanced T1-Weighted Images in the Rat Brain After Repeated, Extended Doses of Gadolinium-Based Contrast Agents

    PubMed Central

    Jost, Gregor; Lenhard, Diana Constanze; Sieber, Martin Andrew; Lohrke, Jessica; Frenzel, Thomas; Pietsch, Hubertus

    2016-01-01

    Objectives In this prospective preclinical study, we evaluated T1-weighted signal intensity in the deep cerebellar nuclei (CN) and globus pallidus (GP) up to 24 days after repeated administration of linear and macrocyclic gadolinium-based contrast agents (GBCAs) using homologous imaging and evaluation methods as in the recently published retrospective clinical studies. In a second part of the study, cerebrospinal fluid (CSF) spaces were evaluated for contrast enhancement by fluid-attenuated magnetic resonance imaging (MRI). Materials and Methods Sixty adult male Wistar-Han rats were randomly divided into a control and 5 GBCA groups (n = 10 per group). The administered GBCAs were gadodiamide, gadopentetate dimeglumine, and gadobenate dimeglumine (linear GBCAs) as well as gadobutrol and gadoterate meglumine (macrocyclic GBCAs) and saline (control). Over a period of 2 weeks, the animals received 10 intravenous injections at a dose of 2.5 mmol Gd/kg body weight, each on 5 consecutive days per week. Before GBCA administration, as well as 3 and 24 days after the last injection, a whole-brain MRI was performed using a standard T1-weighted 3-dimensional turbo spin echo sequence on a clinical 1.5 T scanner. The ratios of signal intensities in deep CN to pons (CN/Po) and GP to thalamus (GP/Th) were determined. For the evaluation of the CSF spaces, 18 additional rats were randomly divided into 6 groups (n = 3 per group) that received the same GBCAs as in the first part of the study. After MR cisternography for anatomical reference, a fluid-attenuated inversion recovery sequence was performed before and 1 minute after intravenous injection of a dose of 1 mmol Gd/kg body weight GBCA or saline. Results A significantly increased signal intensity ratio of CN/Po was observed 3 and 24 days after the last injection of gadodiamide and gadobenate dimeglumine. No significant changes were observed between the 2 time points. Gadopentetate dimeglumine injection led to a moderately elevated

  6. Use of a Mixture of Gadolinium and Iodinated Contrast for Angiography

    SciTech Connect

    Badiola, Carlos M.

    2004-03-15

    The purpose of this study was to determine if the image quality of gadolinium digital subtraction angiography (DSA) can be improved by the addition of small quantities of iodinated contrast to gadolinium. The optical density (OD) of a mixture of four parts gadolinium-based contrast to one part iodinated contrast was measured through a phantom study and compared to that of full-strength gadolinium, full strength iodinated contrast, and a 20% solution of iodinated contrast. We also compared the clinical image quality of the mixture of gadolinium-based contrast and iodinated contrast relative to full-strength gadolinium and full strength iodinated contrast during DSA. The DSA image quality of the gadolinium-iodinated contrast mixture was significantly improved relative to images obtained with full-strength gadolinium and compared favorably to that obtained with full-strength iodinated contrast. The phantom data showed that the OD of the gadolinium-iodinated contrast mixture was much greater than that of full strength gadolinium and the 20% iodinated contrast solution. The increase in OD was greater than that expected from a simple additive effect of the OD of the contrast agents. Adding a small amount of iodinated contrast to gadolinium results in a significant improvement in the radiographic density and DSA image quality of gadolinium. This simple technique appears to overcome one of the major limitations of gadolinium-based angiography-poor radiographic density-while continuing to minimize the volume of administered iodinated contrast.

  7. Gadolinium photoionization process

    DOEpatents

    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.

  8. Gadolinium photoionization process

    DOEpatents

    Paisner, J.A.; Comaskey, B.J.; Haynam, C.A.; Eggert, J.H.

    1993-04-13

    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.

  9. Mass spectrometry in identification of ecotoxicants including chemical and biological warfare agents.

    PubMed

    Lebedev, Albert T

    2005-09-01

    Mass spectrometry is a unique tool to detect and identify trace levels of organic and bioorganic compounds as well as microorganisms in the environment. The range of potential chemical warfare (CW) and biological warfare (BW) agents is very broad. An important advantage of mass spectrometry over other techniques involves potential for full spectrum detection of chemical and biological agents including mid-spectrum materials (i.e. bioactive peptides, toxins, etc.) for which biological approaches are inadequate. Being very fast (seconds and minutes), extremely sensitive (zeptomoles 10(-21)), and informative (detailed qualitative and quantitative composition of mixtures containing hundreds of chemicals), mass spectrometry is a principal analytical tool at the sites of destruction of CW. Due to its unique features, mass spectrometry is applied not only for the detection of CW agents, but for the analysis of products of metabolism and degradation of these agents in organisms or environment as well. The present paper deals with some examples of successful application of mass spectrometry for the analyses of ecotoxicants, chemical warfare agents, explosives, and microorganisms including biology warfare agents.

  10. Mass spectrometry in identification of ecotoxicants including chemical and biological warfare agents

    SciTech Connect

    Lebedev, Albert T. . E-mail: lebedev@org.chem.msu.ru

    2005-09-01

    Mass spectrometry is a unique tool to detect and identify trace levels of organic and bioorganic compounds as well as microorganisms in the environment. The range of potential chemical warfare (CW) and biological warfare (BW) agents is very broad. An important advantage of mass spectrometry over other techniques involves potential for full spectrum detection of chemical and biological agents including mid-spectrum materials (i.e. bioactive peptides, toxins, etc.) for which biological approaches are inadequate. Being very fast (seconds and minutes), extremely sensitive (zeptomoles 10{sup -21}), and informative (detailed qualitative and quantitative composition of mixtures containing hundreds of chemicals), mass spectrometry is a principal analytical tool at the sites of destruction of CW. Due to its unique features, mass spectrometry is applied not only for the detection of CW agents, but for the analysis of products of metabolism and degradation of these agents in organisms or environment as well. The present paper deals with some examples of successful application of mass spectrometry for the analyses of ecotoxicants, chemical warfare agents, explosives, and microorganisms including biology warfare agents.

  11. Effects of gadolinium-based contrast agent concentrations (0.5 M or 1.0 M) on the diagnostic performance of magnetic resonance imaging examinations: systematic review of the literature.

    PubMed

    Lancelot, Eric; Froehlich, John; Heine, Oliver; Desché, Pierre

    2016-11-01

    Background To date there is no agreement as to what is the optimal concentration for gadolinium-based contrast agents (GBCAs). Purpose To assess whether diagnostic performance differences exist between 0.5 M and 1.0 M GBCAs used for magnetic resonance imaging (MRI). Material and Methods A PubMed literature search identified 21 clinical studies published between 2005 and 2013 which evaluated the diagnostic efficacy of both types of GBCAs. Study design, type of procedure, GBCA administration mode, imaging performances, impact on patient management, study limitations, and biases were analyzed. No statistical test was performed on pooled data. Results Sixteen comparative and five non-comparative studies were analyzed, involving 2183 patients who underwent MRI procedures for various indications. In 67% of the studies, 0.5 M and 1.0 M GBCAs were injected at equimolar gadolinium amounts per kg body weight. Only 33% applied the same molar flow rate for delivery of the GBCAs. No significant differences between GBCAs were reported for 23 out of 27 qualitative endpoints (mainly image quality, lesion, and vessel visualization) and 29 out of 40 quantitative endpoints. Three out of four studies with non-equimolar delivery rates showed better contrast-to-noise and signal-to-noise ratios for 1.0 M gadobutrol, without showing an impact on diagnostic performance. Methodological biases were identified in several studies impairing the interpretation of comparisons. Conclusion Imaging differences between 0.5 M and 1.0 M GBCAs were essentially observed under non-equimolar delivery rates. However, they did not result into greater diagnostic efficacy when performed under equimolar conditions.

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

    SciTech Connect

    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.

  13. MRI-guided neutron capture therapy by use of a dual gadolinium/boron agent targeted at tumour cells through upregulated low-density lipoprotein transporters.

    PubMed

    Geninatti-Crich, Simonetta; Alberti, Diego; Szabo, Ibolya; Deagostino, Annamaria; Toppino, Antonio; Barge, Alessandro; Ballarini, Francesca; Bortolussi, Silva; Bruschi, Piero; Protti, Nicoletta; Stella, Sabrina; Altieri, Saverio; Venturello, Paolo; Aime, Silvio

    2011-07-18

    The upregulation of low-density lipoprotein (LDL) transporters in tumour cells has been exploited to deliver a sufficient amount of gadolinium/boron/ligand (Gd/B/L) probes for neutron capture therapy, a binary chemio-radiotherapy for cancer treatment. The Gd/B/L probe consists of a carborane unit (ten B atoms) bearing an aliphatic chain on one side (to bind LDL particles), and a Gd(III)/1,4,7,10-tetraazacyclododecane monoamide complex on the other (for detection by magnetic resonance imaging (MRI)). Up to 190 Gd/B/L probes were loaded per LDL particle. The uptake from tumour cells was initially assessed on cell cultures of human hepatoma (HepG2), murine melanoma (B16), and human glioblastoma (U87). The MRI assessment of the amount of Gd/B/L taken up by tumour cells was validated by inductively coupled plasma-mass-spectrometric measurements of the Gd and B content. Measurements were undertaken in vivo on mice bearing tumours in which B16 tumour cells were inoculated at the base of the neck. From the acquisition of magnetic resonance images, it was established that after 4-6 hours from the administration of the Gd/B/L-LDL particles (0.1 and 1 mmol kg(-1) of Gd and (10)B, respectively) the amount of boron taken up in the tumour region is above the threshold required for successful NCT treatment. After neutron irradiation, tumour growth was followed for 20 days by MRI. The group of treated mice showed markedly lower tumour growth with respect to the control group.

  14. Indirect magnetic resonance lymphography of the head and neck of dogs using Gadofluorine M and a conventional gadolinium contrast agent: a pilot study.

    PubMed

    Mayer, Monique N; Kraft, Susan L; Bucy, Daniel S; Waldner, Cheryl L; Elliot, Kirsten M; Wiebe, Sheldon

    2012-10-01

    The purpose of this pilot study was to evaluate lymph node enhancement with an indirect magnetic resonance (MR) lymphography technique using 2 different contrast agents in the head and neck region of healthy dogs. Five dogs were imaged at various times after intradermal injection of gadoversetamide and Gadofluorine M (minimum of 1 week apart) in the right and left mandibular, temporal, and lateral neck regions. We observed consistent progressive enhancement with time in the mandibular, retropharyngeal, and superficial cervical lymph nodes. The node enhancement was comparable for both contrast agents. Contrast enhancement of the parotid lymph nodes was not seen. We conclude that this technique of indirect MR lymphography using either agent could be used to identify those lymph nodes at highest risk of metastatic disease in dogs with cancer, and to guide staging and treatment.

  15. Encapsulation of Gadolinium Oxide Nanoparticle (Gd2O3) Contrasting Agents in PAMAM Dendrimer Templates for Enhanced Magnetic Resonance Imaging in Vivo.

    PubMed

    Mekuria, Shewaye Lakew; Debele, Tilahun Ayane; Tsai, Hsieh-Chih

    2017-03-01

    There has been growing interest in the research of nanomaterials for biomedical applications in recent decades. Herein, a simple approach to synthesize the G4.5-Gd2O3-poly(ethylene glycol) (G4.5-Gd2O3-PEG) nanoparticles (NPs) that demonstrate potential as dual (T1 and T2) contrasting agents in magnetic resonance imaging (MRI) has been reported in this study. Compared to the clinically popular Gd-DTPA contrasting agents, G4.5-Gd2O3-PEG NPs exhibited a longer longitudinal relaxation time (T1) and better biocompatibility when incubated with macrophage cell line RAW264.7 in vitro. Furthermore, the longitudinal relaxivity (r1) of G4.5-Gd2O3-PEG NPs was 53.9 s(-1) mM(-1) at 7T, which is equivalent to 4.8 times greater than to the Gd-DTPA contrasting agents. An in vivo T1-weighted MRI results revealed that G4.5-Gd2O3-PEG NPs significantly enhanced signals in the intestines, kidney, liver, bladder, and spleen. In addition, the T2-weighted MRI results revealed darker contrast in the kidney, which proves that G4.5-Gd2O3-PEG NPs can be exploited as T1 and T2 contrasting agents. In summary, these findings suggest that the G4.5-Gd2O3-PEG NPs synthesized by an alternative approach can be used as dual MRI contrasting agents.

  16. New treatment strategy including biological agents in patients with systemic lupus erythematosus.

    PubMed

    Leszczyński, Piotr; Pawlak-Buś, Katarzyna

    2013-01-01

    Systemic lupus erythematosus (SLE) is a heterogeneous disease, in which B lymphocyte activation and chronic inflammation play the key role. Both the disease itself and its treatment cause damage to multiple organs and systems. So far, despite intensive treatment, disease remission has been achieved in few patients, and the ratio of organ complications has increased significantly. This is caused by a long‑term glucocorticoid therapy with a relatively rare use of immunosuppressive drugs. With a new treatment strategy and modern immunotherapy, it is possible to reduce the mortality rate, limit multiple‑organ damage, thereby significantly improving the quality of life and prognosis of patients with SLE. The "treat‑to‑target" strategy enables targeted treatment resulting in a long‑term symptom remission. It is based on an intensive immunosuppressive treatment with simultaneous reduction of glucocorticoid doses, and limiting their use solely to exacerbations in disease activity. The current idea for treatment is also the conscious use of the beneficial potential of background SLE treatment including antimalarial agents and standard immunosuppressive therapy. With the first biological agent approved for SLE treatment, the new age of therapy has dawned. Biologics offer new prospects and possibilities to induce clinical and immunological remission of SLE.

  17. Neuroinflammation in Alzheimer's disease: different molecular targets and potential therapeutic agents including curcumin.

    PubMed

    Ray, Balmiki; Lahiri, Debomoy K

    2009-08-01

    Alzheimer's disease (AD) is a neurodegenerative disorder of the elderly. Deposition of amyloid beta plaque and associated neuroinflammation are the major hallmarks of AD. Whereas reactive oxygen species (ROS) and activated microglial cells contribute to neuronal loss, nuclear factor kappaB and apolipoprotein E participate in inflammatory process of AD. Current FDA approved drugs provide only symptomatic relief in AD. For broad spectrum of activity, some natural products are also being tested. Turmeric is used as an anti-inflammatory medicine in various regions of Asia. Curcumin, which is a yellow colored polyphenol compound present in turmeric, showed anti-inflammatory properties. Herein, we discuss the neurobiological and neuroinflammatory pathways of AD, evaluate different molecular targets and potential therapeutic agents, including curcumin, for the treatment of AD.

  18. Clearance of Gadolinium from the Brain with No Pathologic Effect after Repeated Administration of Gadodiamide in Healthy Rats: An Analytical and Histologic Study.

    PubMed

    Smith, Adrian P L; Marino, Michael; Roberts, Jeanette; Crowder, Janell M; Castle, Jason; Lowery, Lisa; Morton, Christine; Hibberd, Mark G; Evans, Paul M

    2017-03-01

    Purpose To measure the levels of gadolinium present in the rat brain 1 and 20 weeks after dosing with contrast agent and to determine if there are any histopathologic sequelae. Materials and Methods The study was approved by the GE Global Research Center Institutional Animal Care and Use Committee. Absolute gadolinium levels were quantified in the blood and brains of rats 1 week after dosing and 20 weeks after dosing with up to 20 repeat doses of gadodiamide (cumulative dose, 12 mmol per kilogram of body weight) by using inductively coupled plasma-mass spectrometry. Treatment groups (n = 6 rats per group) included low-dosage and high-dosage gadodiamide and osmolality-matched saline controls. Brain sections were submitted (blinded) for standard toxicology assessment per Registry of Industrial Toxicology Animal data guidelines. Analysis of variance and Mann-Whitney U tests with post hoc correction were used to assess differences in absolute gadolinium levels and percentage of injected dose, respectively. Results Dose-dependent low levels of gadolinium were detected in the brain, a mean ± standard deviation of 2.49 nmol per gram of brain tissue ± 0.30 or 0.00019% of the injected dose 1 week after dosing. This diminished by approximately 50% (to 1.38 nmol per gram of brain tissue ± 0.10 or 0.00011% of the injected dose) 20 weeks after dosing. As a percentage of injected dose, the levels of gadolinium measured were comparable between different doses, indicating that mechanisms of uptake and elimination were not saturated at the tested doses. There were no histopathologic findings associated with the levels of gadolinium measured. Conclusion Low levels of gadolinium are present in the brain after repeat dosing with gadodiamide, which is partially cleared over 20 weeks with no detectable neurotoxicity.

  19. The effects of emulsifying agents on disposition of lipid-soluble drugs included in fat emulsion.

    PubMed

    Suzuki, Yasuyuki; Masumitsu, Yasushi; Okudaira, Kazuho; Hayashi, Masahiro

    2004-02-01

    The uses for drug delivery systems of two soybean oil fat emulsions prepared with an emulsifying agent, phosphatidyl choline (PC) or Pluronic F-127 (PLU), were examined comparatively in vivo and in vitro. In the presence of lipoprotein lipase (LPL) in vitro, the mean particle size of the PLU emulsion changed less than that of the PC emulsion. The production of non-esterified fatty acid (NEFA) from the PLU emulsion in the presence of LPL was smaller than that from the PC emulsion. These in vitro results indicate that the PLU emulsion is more stable than the PC emulsion. Plasma NEFA concentration following intravenous administration of the emulsions decreased with time for the PC emulsion, but was kept lower and constant for the PLU emulsion, supporting the in vitro stability data. The order of plasma cyclosporine A (CsA) concentration following intravenous administration in the above two emulsions and the mixed solution of polyethylene glycol 400 (PEG) and dimethylamide (DMA) in rats was PLU emulsion>PC emulsion>PEG/DMA solution. The plasma concentration was maintained higher and tissue distribution lower for the PLU emulsion than for other formulations. The uptake of oil violet (OV) into the rat parenchymal cells from the PLU emulsion was approximately half that from the PC emulsion, but the uptake into the Kupffer cells was almost equal in both emulsions. In conclusion, these emulsifying agents can control plasma elimination and tissue distribution of lipophilic drugs included in the emulsion. The use of the emulsion formulation makes it possible to avoid side effects through the reduction of drug uptake into non-targeted tissues.

  20. Advancing the agent methodology to include the higher order of neutron anisotropy with accelerated solutions

    NASA Astrophysics Data System (ADS)

    Satvat, Nader

    With the development of new core designs for generation IV reactors with their complexity and newer fuel designs, the need for consideration of neutron anisotropic scattering is becoming important for enchasing the economy and reliability of these designs. The theory and accurate modeling of neutron anisotropy is one of the most important problems of the transport solution to neutron Boltzmann equation. A number of methods based on careful theoretical developments, were established to numerically determine the effect of anisotropy; some of these methods are: the spherical harmonics method, the so-called function method (FN), the discrete ordinate method, and the Monte Carlo method. The AGENT methodology, based on the method of characteristics, currently the most accurate neutron transport method, represents the state-of-the-art advanced neutronics simulation tool available for 2D, 3D, and full core modeling. The higher order of anisotropic scattering (with no limitation of the number of expansion) is introduced into the AGENT code. An extensive analysis is performed to verify and validate this new model. It is shown that anisotropic scattering is important to be considered for complex geometries due to high angular dependence of neutron flux. The first principle in physics were used to explain the effects of anisotropic scattering (at the level on particle interactions), importance in including the higher moments in flux development for the core designs of high heterogonous structure promoting biased scattering (at the level of heterogeneous reactor assemblies in 2D and 3D). This inclusion of higher order of anisotropic scattering as expected increased the complexity of the mathematical model which in turn increased the computational time. An analysis of the computational time dependence on anisotropic scattering and the method of characteristics resolution parameters are analyzed with accurate predictions of scaling to larger geometries. Finally, an accelerated

  1. Synthesis, conjugation and relaxation studies of gadolinium(III)-4-benzothiazol-2-yl-phenylamine as a potential brain specific MR contrast agent.

    PubMed

    Saini, Nisha; Varshney, Raunak; Tiwari, Anjani K; Kaul, Ankur; Allard, Michele; Ishar, M P S; Mishra, Anil K

    2013-04-14

    Magnetic resonance (MR) imaging is widely used in clinical research to map the structural and functional organization of the brain. We have designed and synthesized a Gd-based specific MR contrast agent that binds to regions in the brain. The presented compound {4-[(4-benzothiazol-2-yl-phenylcarbamoyl)-methyl]-7,10-bis-carboxymethyl-1,4,7,10-tetraazacyclododec-1-yl} acetic acid (DO3A-BT) was synthesized by conjugating the chloroacetylated product of 4-benzothiazol-2-yl-phenylamine with a trisubstituted cyclen. The lanthanide complex (Ln-DO3A-BT) was evaluated in vitro for both MR (Gd-DO3A-BT) and optical (Eu-DO3A-BT) imaging applications. The complex Gd-DO3A-BT displays a relaxivity of r1 = 4.18 mM(-1) s(-1) at 4.7 T which is 1.2 times greater than Dotarem and significantly higher than the brain specific MR contrast agent Luxol Fast Blue (LFB). The protonation constant of the ligand (pKa1 = 9.91, pKa2 = 8.22, pKa3 = 5.01) and the stability constant of the complex formed between Gd(III), Eu(III) and Ca(II) and ligand DO3A-BT (log βGdL = 18.4, log βEuL = 18.3, log βZn2L = 7.1, log βCa2L = 6.3) were recorded by potentiometric titration. The constants reflect the high stability of the ligand with lanthanides compared with endogenous metal ions. The transmetalation stability of Gd-DO3A-BT toward Zn proved to be excellent with a rate constant of 3.07 × 10(-5) s(-1) which is in line with other tetraazatetraacetic acid (DOTA)-monoamide complexes. The hydration number (q) was found to be 0.92, and is calculated from the difference in the luminescence lifetime of Eu-DO3A-BT in H2O and D2O solutions to determine the coordination state of this complex. The in vivo biodistribution of (99m)Tc-DO3A-BT in BALB/c mice showed a brain uptake of 1.2% ID g(-1) at 2 min post injection when injected with mannitol which disrupts the blood-brain-barrier (BBB) due to osmotic shock. In vitro binding on the brain homogenate revealed a high uptake by the neuronal/glial cells for in vivo

  2. SIMS imaging of gadolinium isotopes in tissue from Nephrogenic Systemic Fibrosis patients: Release of free Gd from magnetic resonance imaging (MRI) contrast agents

    NASA Astrophysics Data System (ADS)

    Abraham, Jerrold L.; Chandra, Subhash; Thakral, Charu; Abraham, Joshua M.

    2008-12-01

    Recently, Gd-based magnetic resonance imaging (MRI) contrast agents (GBMCA) have been linked to a new disease, Nephrogenic Systemic Fibrosis (NSF), with skin and systemic toxicity and death in certain patients with renal failure. Due to widespread use of GBMCA in diagnostic MRI, it is essential to study their excretion, metabolism, and target sites in cells and tissues. A CAMECA IMS-3f SIMS ion microscope and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) were used for imaging Gd isotopes in relation to calcium distributions in histologic sections of human tissues. SIMS imaging revealed two types of Gd localization in skin biopsies of patients who received GBMCA. The Gd was present in micrometer size deposits in association with calcium, and in detectable amounts in a more diffuse cellular distribution. Only the Gd-containing deposits associated with Ca and P were detectable using SEM/EDS. As only insoluble deposits remain in the biopsy tissues after aqueous and organic solvent processing of the tissue, our observations support release of free Gd from the GBMCA and selective localization of insoluble Gd in the target tissue from patients with NSF. This study opens new novel applications of SIMS for characterization of the safety of GBMCA.

  3. Distribution profile of gadolinium in gadolinium chelate-treated renally-impaired rats: role of pharmaceutical formulation.

    PubMed

    Fretellier, Nathalie; Salhi, Mariem; Schroeder, Josef; Siegmund, Heiko; Chevalier, Thibaut; Bruneval, Patrick; Jestin-Mayer, Gaëlle; Delaloge, Francette; Factor, Cécile; Mayer, Jean-François; Fabicki, Jean-Michel; Robic, Caroline; Bonnemain, Bruno; Idée, Jean-Marc; Corot, Claire

    2015-05-25

    While not acutely toxic, chronic hepatic effect of certain gadolinium chelates (GC), used as contrast agent for magnetic resonance imaging, might represent a risk in renally-impaired patients due to free gadolinium accumulation in the liver. To answer this question, this study investigated the consequences of the presence of small amounts of either a soluble gadolinium salt ("free" Gd) or low-stability chelating impurity in the pharmaceutical solution of gadoteric acid, a macrocyclic GC with high thermodynamic and kinetic stabilities, were investigated in renally-impaired rats. Renal failure was induced by adding 0.75% adenine in the diet for three weeks. The pharmaceutical and commercial solution of gadoteric acid was administered (5 daily intravenous injections of 2.5 mmol Gd/kg) either alone or after being spiked with either "free" gadolinium (i.e., 0.04% w/v) or low-stability impurity (i.e., 0.06 w/v). Another GC, gadodiamide (low thermodynamic and kinetic stabilities) was given as its commercial solution at a similar dose. Non-chelated gadolinium was tested at two doses (0.005 and 0.01 mmol Gd/kg) as acetate salt. Gadodiamide induced systemic toxicity (mortality, severe epidermal and dermal lesions) and substantial tissue Gd retention. The addition of very low amounts of "free", non-chelated gadolinium or low thermodynamic stability impurity to the pharmaceutical solution of the thermodynamically stable GC gadoteric acid resulted in substantial capture of metal by the liver, similar to what was observed in "free" gadolinium salt-treated rats. Relaxometry studies strongly suggested the presence of free and soluble gadolinium in the liver. Electron microscopy examinations revealed the presence of free and insoluble gadolinium deposits in hepatocytes and Kupffer cells of rats treated with gadoteric acid solution spiked with low-stability impurity, free gadolinium and gadodiamide, but not in rats treated with the pharmaceutical solution of gadoteric acid. The

  4. Importance of outer-sphere and aggregation phenomena in the relaxation properties of phosphonated gadolinium complexes with potential applications as MRI contrast agents.

    PubMed

    Elhabiri, Mourad; Abada, Sabah; Sy, Mohamadou; Nonat, Aline; Choquet, Philippe; Esteban-Gómez, David; Cassino, Claudio; Platas-Iglesias, Carlos; Botta, Mauro; Charbonnière, Loïc J

    2015-04-20

    A series composed of a tetra-, a tris- and a bisphosphonated ligand based on a pyridine scaffold (L(4) , L(3) and L(2) , respectively) was studied within the frame of lanthanide (Ln) coordination. The stability constants of the complexes formed with lanthanide cations (Ln=La, Nd, Eu, Gd, Tb, Er and Lu) were determined by potentiometry in aqueous solutions (25.0 °C, 0.1 M NaClO4 ), showing that the tetraphosphonated complexes are among the most stable Ln(III) complexes reported in the literature. The complexation of L(4) was further studied by different titration experiments using mass spectrometry and various spectroscopic techniques including UV/Vis absorption, and steady state and time-resolved luminescence (Ln=Eu and Tb). Titration experiments confirmed the formation of highly stable [LnL(4) ] complexes. (31) P NMR experiments of the LuL(4) complex revealed an intramolecular interconversion process which was studied at different temperatures and was rationalized by DFT modelling. The relaxivity properties of the Gd(III) complexes were studied by recording their (1) H NMRD profiles at various temperatures, by temperature dependent (17) O NMR experiments (GdL(4) ) and by pH dependent relaxivity measurements at 0.47 T (GdL(3) and GdL(2) ). In addition to the high relaxivity values observed for all complexes, the results showed an important second-sphere contribution to relaxivity and pH dependent variations associated with the formation of aggregates for GdL(2) and GdL(3) . Finally, intravenous injection of GdL(4) to a mouse was followed by dynamic MRI imaging at 1.5 T, which showed that the complex can be immediately found in the blood stream and rapidly eliminated through the liver and in large part through the kidneys.

  5. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Use of mercury compounds in cosmetics including...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.13 Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. (a)...

  6. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Use of mercury compounds in cosmetics including...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.13 Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. (a)...

  7. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Use of mercury compounds in cosmetics including...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.13 Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. (a)...

  8. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Use of mercury compounds in cosmetics including...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.13 Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. (a)...

  9. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... topical application and is accumulated in the body, giving rise to numerous adverse effects. Mercury is a... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. 700.13 Section 700.13...

  10. Thermodynamic properties of gadolinium disilicide

    SciTech Connect

    Lukashenko, G.M.; Polotskaya, R.I.

    1986-11-01

    The authors determine the Gibbs energy, enthalpy, formation heat, and other thermodynamic properties of gadolinium disilicide by measuring the electromotive force in the 830-960 K temperature range in electrolytes consisting of molten tin and various chlorides. The relationship of these properties to crystal structure is briefly discussed.

  11. Experience with gadolinium at yankee

    SciTech Connect

    Cacciapouti, R.J.; Sironen, M.A.; Kaptiz, D.M.; Potter, R.C.

    1985-11-01

    The Vermont Yankee nuclear power station, a boiling water reactor, has been operating with gadolinium in the fuel bundles since 1973. The gadolinium has ranged from 2.0 to 4.0 wt% in 7 x 7, 8 x 8, and retrofit 8 x 8 bundle designs. When Yankee Atomic Electric Company initiated its program in 1978 to perform reload licensing analysis, these bundles and the core designs had to be modeled accurately. The basic calculational model consists of the cross section generation code, CASMO, and the three-dimensional nodal code, SIMULATE. The gadolinium cross sections for use in CASMO were generated using MICBURN to model each gadolinium pin individually. This combination of codes has been used to calculate 11 cycles of operation at Vermont Yankee. The model has been depleted each cycle using explicit plant conditions at equilibrium xenon. At various state points, the eigenvalues, hot and cold, were calculated and tabulated for each cycle. Comparisons were made between plant-measured and SIMULATE-calculated TIP values and between process computer and SIMULATE thermal margins. The model is also used to predict future cycle operating conditions and thermal margins based on past comparisons.

  12. Tumor-induced lymph node alterations detected by MRI lymphography using gadolinium nanoparticles.

    PubMed

    Partridge, S C; Kurland, B F; Liu, C-L; Ho, R J Y; Ruddell, A

    2015-10-26

    Contrast-enhanced MRI lymphography shows potential to identify alterations in lymph drainage through lymph nodes (LNs) in cancer and other diseases. MRI studies have typically used low molecular weight gadolinium contrast agents, however larger gadolinium-loaded nanoparticles possess characteristics that could improve the specificity and sensitivity of lymphography. The performance of three gadolinium contrast agents with different sizes and properties was compared by 3T MRI after subcutaneous injection. Mice bearing B16-F10 melanoma footpad tumors were imaged to assess tumor-induced alterations in lymph drainage through tumor-draining popliteal and inguinal LNs versus contralateral uninvolved drainage. Gadolinium lipid nanoparticles were able to identify tumor-induced alterations in contrast agent drainage into the popliteal LN, while lower molecular weight or albumin-binding gadolinium agents were less effective. All of the contrast agents distributed in foci around the cortex and medulla of tumor-draining popliteal LNs, while they were restricted to the cortex of non-draining LNs. Surprisingly, second-tier tumor-draining inguinal LNs exhibited reduced uptake, indicating that tumors can also divert LN drainage. These characteristics of tumor-induced lymph drainage could be useful for diagnosis of LN pathology in cancer and other diseases. The preferential uptake of nanoparticle contrasts into tumor-draining LNs could also allow selective targeting of therapies to tumor-draining LNs.

  13. Structural and chemical analysis of gadolinium halides encapsulated within WS2 nanotubes

    NASA Astrophysics Data System (ADS)

    Anumol, E. A.; Enyashin, Andrey N.; Batra, Nitin M.; Costa, Pedro M. F. J.; Deepak, Francis Leonard

    2016-06-01

    The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the presence of multiple high atomic number elements. Therefore, energy dispersive X-ray spectroscopy (EDS) tomography was employed revealing the three dimensional chemical composition. Molecular dynamics simulations of the filling procedure shed light into the mechanics behind the formation of the confined gadolinium halide crystals. The quasi-1D system employed here serves as an example of a TEM-based chemical nanotomography method that could be extended to other materials, including beam-sensitive soft materials.The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the

  14. Discovery of samarium, europium, gadolinium, and terbium isotopes

    SciTech Connect

    May, E.; Thoennessen, M.

    2013-01-15

    Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium, and thirty-one terbium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  15. Type of MRI contrast, tissue gadolinium, and fibrosis.

    PubMed

    Do, Catherine; Barnes, Jeffrey L; Tan, Chunyan; Wagner, Brent

    2014-10-01

    It has been presupposed that the thermodynamic stability constant (K(therm)) of gadolinium-based MRI chelates relate to the risk of precipitating nephrogenic systemic fibrosis. The present study compared low-K(therm) gadodiamide with high-K(therm) gadoteridol in cultured fibroblasts and rats with uninephrectomies. Gadolinium content was assessed using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy in paraffin-embedded tissues. In vitro, fibroblasts demonstrated dose-dependent fibronectin generation, transforming growth factor-β production, and expression of activated myofibroblast stress fiber protein α-smooth muscle actin. There were negligible differences with respect to toxicity or proliferation between the two contrast agents. In the rodent model, gadodiamide treatment led to greater skin fibrosis and dermal cellularity than gadoteridol. In the kidney, both contrast agents led to proximal tubule vacuolization and increased fibronectin accumulation. Despite large detectable gadolinium signals in the spleen, skin, muscle, and liver from the gadodiamide-treated group, contrast-induced fibrosis appeared to be limited to the skin and kidney. These findings support the hypothesis that low-K(therm) chelates have a greater propensity to elicit nephrogenic systemic fibrosis and demonstrate that certain tissues are resistant to these effects.

  16. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    PubMed

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K; Varani, James

    2012-12-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

  17. Metals Fact Sheet: Gadolinium GD

    SciTech Connect

    1992-10-01

    Gadolinium is a silvery-white, malleable, ductile metallic element used to improve the high-temperature characteristics of iron, chromium, and related metallic alloys. It was named after the French chemist, Gadolin, discoverer of yttrium. This article discusses sources of the element, the world supply and demand, and also a number of applications. With the largest thermal neutron absorption cross section of any element, one of these applications is as a burnable poison in reactors and as neutron absorbers in other nuclear devices.

  18. Removal of gadolinium nitrate from heavy water

    SciTech Connect

    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).

  19. Gadolinium-enhanced computed tomography cystogram to diagnose bladder augment rupture in patients with iodine sensitivity.

    PubMed

    Newport, John Paul; Dusseault, Beau N; Butler, Carina; Pais, Vernon M

    2008-05-01

    Anaphylactic reaction to iodinated contrast is a potentially life-threatening complication of diagnostic imaging studies. We report the successful use of gadolinium as an alternative contrast agent for computed tomography cystogram in a patient with a history of anaphylactic reaction to iodinated contrast. This technique allowed us rapidly to diagnose a rupture of her bladder augmentation and pursue operative repair.

  20. Gadolinium-based nanoparticles for theranostic MRI-radiosensitization.

    PubMed

    Lux, François; Sancey, Lucie; Bianchi, Andrea; Crémillieux, Yannick; Roux, Stéphane; Tillement, Olivier

    2015-01-01

    A rapid development of gadolinium-based nanoparticles is observed due to their attractive properties as MRI-positive contrast agents. Indeed, they display high relaxivity, adapted biodistribution and passive uptake in the tumor thanks to enhanced permeability and retention effect. In addition to these imaging properties, it has been recently shown that they can act as effective radiosensitizers under different types of irradiation (radiotherapy, neutron therapy or hadron therapy). These new therapeutic modalities pave the way to therapy guided by imaging and to personalized medicine.

  1. High Performance Anion Chromatography of Gadolinium Chelates.

    PubMed

    Hajós, Peter; Lukács, Diana; Farsang, Evelin; Horváth, Krisztian

    2016-11-01

    High performance anion chromatography (HPIC) method to separate ionic Gd chelates, [Formula: see text], [Formula: see text], [Formula: see text] and free matrix anions was developed. At alkaline pHs, polydentate complexing agents such as ethylene-diamine-tetraacetate, diethylene-triamine pentaacetate and trans-1,2-diamine-cyclohexane-tetraacetate tend to form stable Gd chelate anions and can be separated by anion exchange. Separations were studied in the simple isocratic chromatographic run over the wide range of pH and concentration of carbonate eluent using suppressed conductivity detection. The ion exchange and complex forming equilibria were quantitatively described and demonstrated in order to understand major factors in the control of selectivity of Gd chelates. Parameters of optimized resolution between concurrent ions were presented on a 3D resolution surface. The applicability of the developed method is represented by the simultaneous analysis of Gd chelates and organic/inorganic anions. Inductively coupled plasma atomic emission spectroscopy  (ICP-AES) analysis was used for confirmation of HPIC results for Gd. Collection protocols for the heart-cutting procedure of chromatograms were applied. SPE procedures were also developed not only to extract traces of free gadolinium ions from samples, but also to remove the high level of interfering anions of the complex matrices. The limit of detection, the recoverability and the linearity of the method were also presented.

  2. Status of gadolinium enrichment technology at LLNL

    SciTech Connect

    Haynam, C.; Comaskey, B.; Conway, J.; Eggert, J.; Glaser, J.; Ng, E.; Paisner, J.; Solarz, R.; Worden, E.

    1993-01-01

    A method based on,polarization selectivity and three step laser photoionization is presented for separation of the odd isotopes of gadolinium. Measurements of the spectroscopic parameters needed to quantify the excitation pathway are discussed. Model results are presented for the efficiency of photoionization. The vapor properties of electron beam vaporized gadolinium are presented which show dramatic cooling during the expansion of the hot dense vapor into a vacuum. This results in a significant increase in the efficiency of conversion of natural feed into enriched product in the AVLIS process. Production of enriched gadolinium for use in commercial power reactors appears to be economically viable using technology in use at LLNL.

  3. Rural-urban migration including formal and informal workers in the urban sector: an agent-based numerical simulation study

    NASA Astrophysics Data System (ADS)

    Branco, Nilton; Oliveira, Tharnier; Silveira, Jaylson

    2012-02-01

    The goal of this work is to study rural-urban migration in the early stages of industrialization. We use an agent-based model and take into account the existence of informal and formal workers on the urban sector and possible migration movements, dependent on the agents' social and private utilities. Our agents are place on vertices of a square lattice, such that each vertex has only one agent. Rural, urban informal and urban formal workers are represented by different states of a three-state Ising model. At every step, a fraction a of the agents may change sectors or migrate. The total utility of a given agent is then calculated and compared to a random utility, in order to check if this agent turns into an actual migrant or changes sector. The dynamics is carried out until an equilibrium state is reached and equilibrium variables are then calculated and compared to available data. We find that a generalized Harris-Todaro condition is satisfied [1] on these equilibrium regimes, i.e, the ratio between expected wages between any pair of sectors reach a constant value. [4pt] [1] J. J. Silveira, A. L. Esp'indola and T. J. Penna, Physica A, 364, 445 (2006).

  4. The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

    NASA Astrophysics Data System (ADS)

    Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

    2016-07-01

    We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps.

  5. The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

    PubMed Central

    Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

    2016-01-01

    We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps. PMID:27411781

  6. Agents.

    PubMed

    Chambers, David W

    2002-01-01

    Although health care is inherently an economic activity, it is inadequately described as a market process. An alternative, grounded in organizational economic theory, is to view professionals and many others as agents, contracted to advance the best interests of their principals (patients). This view untangles some of the ethical conflicts in dentistry. It also helps identify major controllable costs in dentistry and suggests that dentists can act as a group to increase or decrease agency costs, primarily by controlling the bad actors who damage the value of all dentists.

  7. Mechanism of inhibition of ribonucleotide reductase with motexafin gadolinium (MGd)

    SciTech Connect

    Zahedi Avval, Farnaz; Berndt, Carsten; Pramanik, Aladdin; Holmgren, Arne

    2009-02-13

    Motexafin gadolinium (MGd) is an expanded porphyrin anticancer agent which selectively targets tumor cells and works as a radiation enhancer, with promising results in clinical trials. Its mechanism of action is oxidation of intracellular reducing molecules and acting as a direct inhibitor of mammalian ribonucleotide reductase (RNR). This paper focuses on the mechanism of inhibition of RNR by MGd. Our experimental data present at least two pathways for inhibition of RNR; one precluding subunits oligomerization and the other direct inhibition of the large catalytic subunit of the enzyme. Co-localization of MGd and RNR in the cytoplasm particularly in the S-phase may account for its inhibitory properties. These data can elucidate an important effect of MGd on the cancer cells with overproduction of RNR and its efficacy as an anticancer agent and not only as a general radiosensitizer.

  8. A Polymeric Fastener can Easily Functionalize Liposome Surfaces with Gadolinium for Enhanced Magnetic Resonance Imaging

    PubMed Central

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

    2013-01-01

    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. PMID:24083377

  9. Studies of narrow autoionizing resonances in gadolinium

    SciTech Connect

    Bushaw, Bruce A.; Nortershauser, W.; Blaum, K.; Wendt, Klaus

    2003-06-30

    The autoionization (AI) spectrum of gadolinium between the first and second limits has been investigated by triple-resonance excitation with high-resolution cw lasers. A large number of narrow AI resonances have been observed and assigned total angular momentum J values. The resonances are further divided into members of AI Rydberg series converging to the second limit or other ''interloping'' levels. Fine structure in the Rydberg series has been identified and interpreted in terms of Jc j coupling. A number of detailed studies have been performed on the interloping resonances: These include lifetime determination by lineshape analysis, isotope shifts, hyperfine structure, and photoionization saturation parameters. The electronic structure of the interloping levels is discussed in terms of these studies. Linewidths generally decrease with increasing total angular momentum and the J = 7 resonances are extremely narrow with Lorentzian widths ranging from < 1 MHz up to 157 MHz. The strongest resonances are found to have cross-sections of {approx}10-12 cm{sup 2} and photoionization can be saturated with powers available from cw diode lasers.

  10. The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy

    PubMed Central

    Sancey, L; Kotb, S; Roux, S; Dufort, S; Bianchi, A; Crémillieux, Y; Fries, P; Coll, J-L; Rodriguez-Lafrasse, C; Janier, M; Dutreix, M; Barberi-Heyob, M; Boschetti, F; Denat, F; Louis, C; Porcel, E; Lacombe, S; Le Duc, G; Deutsch, E; Perfettini, J-L; Detappe, A; Verry, C; Berbeco, R; Butterworth, K T; McMahon, S J; Prise, K M; Perriat, P; Tillement, O

    2014-01-01

    A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed. PMID:24990037

  11. Structural, optical and magnetic properties of gadolinium sesquioxide nanobars synthesized via thermal decomposition of gadolinium oxalate

    SciTech Connect

    Manigandan, R.; Giribabu, K.; Suresh, R.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2013-10-15

    Graphical abstract: - Highlights: • The cubic Gd{sub 2}O{sub 3} nanobars are synthesized by decomposition of C{sub 6}H{sub 20}Gd{sub 2}O{sub 22}. • The nanoparticles are rectangular bar shape with high porous surface. • The combination of magnetic and optical properties within a single particle. • The Gd{sub 2}O{sub 3} nanobars have tailorable nanostructure, wide bandgap and are paramagnetic. - Abstract: Gadolinium oxide nanobars were obtained by thermal decomposition of gadolinium oxalate, which was synthesized by the chemical precipitation method along with glycerol. The functional group analysis and formation of gadolinium oxide from gadolinium oxalate were characterized by the Fourier transform infrared spectroscopy and thermo gravimetric analyzer. The crystal structure, average crystallite size, and lattice parameter were analyzed by X-ray diffraction technique. Moreover, Raman shifts, elemental composition and morphology of the gadolinium oxide was widely investigated by the laser Raman microscope, X-ray photoelectron spectroscopy, FE-SEM-EDAX and HR-TEM, respectively. Furthermore, the optical properties like band gap, absorbance measurement of the gadolinium oxide were extensively examined. In addition, the paramagnetic property of gadolinium oxide nanobars was explored by the vibrating sample magnetometer.

  12. Enhancement of the electron electric dipole moment in gadolinium garnets

    SciTech Connect

    Mukhamedjanov, T.N.; Dzuba, V.A.; Sushkov, O.P.

    2003-10-01

    Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.

  13. New pyrrole derivatives with potent tubulin polymerization inhibiting activity as anticancer agents including hedgehog-dependent cancer.

    PubMed

    La Regina, Giuseppe; Bai, Ruoli; Coluccia, Antonio; Famiglini, Valeria; Pelliccia, Sveva; Passacantilli, Sara; Mazzoccoli, Carmela; Ruggieri, Vitalba; Sisinni, Lorenza; Bolognesi, Alessio; Rensen, Whilelmina Maria; Miele, Andrea; Nalli, Marianna; Alfonsi, Romina; Di Marcotullio, Lucia; Gulino, Alberto; Brancale, Andrea; Novellino, Ettore; Dondio, Giulio; Vultaggio, Stefania; Varasi, Mario; Mercurio, Ciro; Hamel, Ernest; Lavia, Patrizia; Silvestri, Romano

    2014-08-14

    We synthesized 3-aroyl-1-arylpyrrole (ARAP) derivatives as potential anticancer agents having different substituents at the pendant 1-phenyl ring. Both the 1-phenyl ring and 3-(3,4,5-trimethoxyphenyl)carbonyl moieties were mandatory to achieve potent inhibition of tubulin polymerization, binding of colchicine to tubulin, and cancer cell growth. ARAP 22 showed strong inhibition of the P-glycoprotein-overexpressing NCI-ADR-RES and Messa/Dx5MDR cell lines. Compounds 22 and 27 suppressed in vitro the Hedgehog signaling pathway, strongly reducing luciferase activity in SAG treated NIH3T3 Shh-Light II cells, and inhibited the growth of medulloblastoma D283 cells at nanomolar concentrations. ARAPs 22 and 27 represent a new potent class of tubulin polymerization and cancer cell growth inhibitors with the potential to inhibit the Hedgehog signaling pathway.

  14. New Pyrrole Derivatives with Potent Tubulin Polymerization Inhibiting Activity As Anticancer Agents Including Hedgehog-Dependent Cancer

    PubMed Central

    La Regina, Giuseppe; Bai, Ruoli; Coluccia, Antonio; Famiglini, Valeria; Pelliccia, Sveva; Passacantilli, Sara; Mazzoccoli, Carmela; Ruggieri, Vitalba; Sisinni, Lorenza; Bolognesi, Alessio; Rensen, Whilelmina Maria; Miele, Andrea; Nalli, Marianna; Alfonsi, Romina; Di Marcotullio, Lucia; Gulino, Alberto; Brancale, Andrea; Novellino, Ettore; Dondio, Giulio; Vultaggio, Stefania; Varasi, Mario; Mercurio, Ciro; Hamel, Ernest; Lavia, Patrizia; Silvestri, Romano

    2014-01-01

    We synthesized 3-aroyl-1-arylpyrrole (ARAP) derivatives as potential anticancer agents having different substituents at the pendant 1-phenyl ring. Both the 1-phenyl ring and 3-(3,4,5-trimethoxyphenyl)carbonyl moieties were mandatory to achieve potent inhibition of tubulin polymerization, binding of colchicine to tubulin, and cancer cell growth. ARAP 22 showed strong inhibition of the P-glycoprotein-overexpressing NCI-ADR-RES and Messa/Dx5MDR cell lines. Compounds 22 and 27 suppressed in vitro the Hedgehog signaling pathway, strongly reducing luciferase activity in SAG treated NIH3T3 Shh-Light II cells, and inhibited the growth of medulloblastoma D283 cells at nanomolar concentrations. ARAPs 22 and 27 represent a new potent class of tubulin polymerization and cancer cell growth inhibitors with the potential to inhibit the Hedgehog signaling pathway. PMID:25025991

  15. Gadolinium: Central Metal of the Lanthanoids

    ERIC Educational Resources Information Center

    Laing, Michael

    2009-01-01

    The physical and chemical properties of gadolinium are compared with those of the other lanthanoids. Some properties are intermediate between those of lanthanum and lutetium; some between those of barium and hafnium; and others (unexpectedly) between those of ytterbium and lutetium. Both the remarkably high molar heat capacity of the metal and the…

  16. A toxicological study of gadolinium nitrate

    SciTech Connect

    London, J.E.

    1988-05-01

    The sensitization study in the guinea pig did not show gadolinium nitrate to have potential sensitizing properties. Skin application studies in the rabbit demonstrated that it was cutaneously a severe irritant. This material was considered an irritant in the rabbit eye application studies. 3 refs., 1 tab.

  17. 77 FR 42317 - Establish a Patient-Based Registry To Evaluate the Association of Gadolinium Based Contrast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ... HUMAN SERVICES Food and Drug Administration Establish a Patient-Based Registry To Evaluate the Association of Gadolinium Based Contrast Agents Exposure and Nephrogenic Systemic Fibrosis AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA) is...

  18. The feasibility of in vivo quantification of bone-gadolinium in humans by prompt gamma neutron activation analysis (PGNAA) following gadolinium-based contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Mostafaei, F.; McNeill, F. E.; Chettle, D. R.; Noseworthy, M. D.; Prestwich, W. V.

    2015-11-01

    The feasibility of using a 238Pu/Be-based in vivo prompt γ-ray neutron activation analysis (IVNAA) system, previously successfully used for measurements of muscle, for the detection of gadolinium (Gd) in bone was presented. Gd is extensively used in contrast agents in MR imaging. We present phantom measurement data for the measurement of Gd in the tibia. Gd has seven naturally occurring isotopes, of which two have extremely large neutron capture cross sections; 155Gd (14.8% natural abundance (NA), σ= 60,900 barns) and 157Gd (15.65% NA, σ= 254,000 barns). Our previous work focused on muscle but this only informs about the short term kinetics of Gd. We studied the possibility of measuring bone, as it may be a long term storage site for Gd. A human simulating bone phantom set was developed. The phantoms were doped with seven concentrations of Gd of concentrations 0.0, 25, 50, 75, 100, 120 and 150 ppm. Additional elements important for neutron activation analysis, Na, Cl and Ca, were also included to create an overall elemental composition consistent with Reference Man. The overall conclusion is that the potential application of this Pu-Be-based prompt in vivo NAA for the monitoring of the storage and retention of Gd in bone is not feasible.

  19. Gadolinium Deposition in Nephrogenic Systemic Fibrosis: An Examination of Tissue using Synchrotron X-ray Fluorescence Spectroscopy

    SciTech Connect

    High, W.; Ranville, J; Brown, M; Punshon, T; Lanzirotti, A; Jackson, B

    2010-01-01

    Nephrogenic systemic fibrosis is a fibrosing disorder associated with gadolinium (Gd)-based contrast agents dosed during renal insufficiency. In two patients, Gd deposition in tissue affected by nephrogenic systemic fibrosis was quantified using inductively coupled plasma mass spectrometry. The presence of Gd was confirmed and mapped using synchrotron x-ray fluorescence spectroscopy. Affected skin and soft tissue from the lower extremity demonstrated 89 and 209 ppm ({micro}g/g, dry weight, formalin fixed) in cases 1 and 2, respectively. In case 2, the same skin and soft tissue was retested after paraffin embedding, with the fat content removed by xylene washes, and this resulted in a measured value of 189 ppm ({micro}g/g, dry weight, paraffin embedded). Synchrotron x-ray fluorescence spectroscopy confirmed Gd in the affected tissue of both cases, and provided high-sensitivity and high-resolution spatial mapping of Gd deposition. A gradient of Gd deposition in tissue correlated with fibrosis and cellularity. Gd deposited in periadnexal locations within the skin, including hair and eccrine ducts, where it colocalized to areas of high calcium and zinc content. Because of the difficulty in obtaining synchrotron x-ray fluorescence spectroscopy scans, tissue from only two patients were mapped. A single control with kidney disease and gadolinium-based contrast agent exposure did not contain Gd. Gd content on a gravimetric basis was impacted by processing that removed fat and altered the dry weight of the specimens. Gradients of Gd deposition in tissue corresponded to fibrosis and cellularity. Adnexal deposition of Gd correlated with areas of high calcium and zinc content.

  20. Impact of gadolinium-157 containing nanoscale magnetosensitive composites on morfofunctional properties of cells in vitro.

    PubMed

    Lavrenchuk, H Y; Shevchenko, Y B; Petranovska, A L; Asmolkova, V S; Oksamytnyi, V M; Kozlovska, I V; Yavorska, O H

    2014-09-01

    Objective - to investigate the morphofunctional cells properties under the action of magneticallybased nanocomposites containing gadolinium-157. Materials and methods. Experimental studies are performed in cell culture line L929 Nanocomposites based on magnetite modified by functional amino groups chemically fixed by diethylenetriaminepentaacetic acid (DTPA) and gadolinium - (Fe3O4/γ-APS/DTPA-Gd) were studied (1), also by meso-2,3-dimercaptosuccinic acid (DMSA) - (Fe3O4/DMSA-Gd), which binds to the hydroxyl group of magnetite surface (2); gadolinium was adsorbed from a solution of gadolinium sulfate. Reagent 3 - magnetic substance Fe3O4 with sodium oleate. Morphofunctional characteristics of cell culture were evaluated in various terms by standard indicators of sustainability: proliferative and mitotic activity and the number of giant multinuclear cells, apoptosis. Results and conclusions. We established that magnetdriven nanocomposites with gadolinium modified by DTPA and DMSA, were more biocompatibile to cells: incubation of cells with neutron capture agents (NCA) in the studied range of concentrations showed no toxicity, except maximum concentration, while decreasing cells adhesive properties. For all nanocomposites we observed decrease in mitotic activity in the background of the control cell population density, which may indicate synchronization of cell division. We found that the stabilized by sodium oleate ferrite caused destructive changes in cell culture only at concentrations of 500 μg / ml, but reduced mitotic activity in cell culture in 3-5 times in the whole range of concentrations. It is shown that magnetdriven nanocomposites induce different levels of apoptosis in cultured cells depending on the concentration of the reactants.

  1. Positive gadolinium anomalies in wastewater treatment plant effluents and aquatic environment in the Hérault watershed (South France).

    PubMed

    Rabiet, M; Brissaud, F; Seidel, J L; Pistre, S; Elbaz-Poulichet, F

    2009-05-01

    Anthropogenic gadolinium (Gd), used as a contrast agent in magnetic resonance imaging, may enter rivers and groundwaters with the effluents of wastewater treatment plant (WWTP). Such contaminations, which are mainly found in densely populated areas with highly developed medical systems, induce positive gadolinium anomalies in waters. This study reports on the occurrence of positive Gd anomaly in wastewaters, surface and groundwaters in a slightly populated Mediterranean watershed. Water samples have been collected along the Hérault River, in its tributaries, in wells and springs supplying drinking water and in WWTP effluents during two sampling campaigns in February and July 2003. Systematically pronounced positive gadolinium anomalies (Gd/Gd( *)) were observed in WWTP effluents with values reaching 306. These observations have shown that Gd/Gd( *) can also be found in wastewater drained from rural communities, not equipped with MRI facilities. Positive gadolinium anomalies were detected in two tributaries of the Hérault River and in some wells supplying drinking water, corresponding to an excess of anthropogenic Gd in water up to 15.4pM. A monthly monitoring on one well has confirmed the persistence of gadolinium anomalies all along the year, suggesting a continual wastewater contamination on this site. A spatial monitoring on one tributary showed that wastewater contribution modifies completely the normalized REE pattern of river water, resulting in a decrease of REE amount correlated to the Gd anomaly appearance.

  2. Polymeric gastrointestinal MR contrast agents.

    PubMed

    Tilcock, C; Unger, E C; Ahkong, Q F; Fritz, T; Koenig, S H; Brown, R D

    1991-01-01

    Combining either paramagnetic (gadolinium chelates) or superparamagnetic (ferrite) contrast agents with polymers such as polyethylene glycol or cellulose, or with simple sugars such as dextrose, results in mixtures that exhibit improved T1 and/or T2 relaxivity compared with that of the contrast agent alone. It is suggested that the addition of such inexpensive and nontoxic polymers or saccharides may improve the effectiveness and decrease the cost of enteric contrast agents.

  3. Method of separating and purifying gadolinium-153

    DOEpatents

    Bray, Lane A [Richland, WA; Corneillie, Todd M [Davis, CA

    2001-01-01

    The present invention is an improvement to the method of separating and purifying gadolinium from a mixture of gadolinium and europium having the steps of (a) dissolving the mixture in an acid; (b) reducing europium+3 to europium+2; and (c) precipitating the europium+2 with a sulfate ion in a superstoichiometric amount; wherein the improvement is achieved by using one or more of the following: (i) the acid is an anoic acid; (ii) the reducing is with zinc metal in the absence of a second metal or with an amount of the second metal that is ineffective in the reducing; (iii) adding a group IIA element after step (c) for precipitating the excess sulfate prior to repeating step (c); (iv) the sulfate is a sulfate salt with a monovalent cation; (v) adding cold europium+3 prior to repeating step (c).

  4. MRI gadolinium enhancement precedes neuroradiological findings in acute necrotizing encephalopathy.

    PubMed

    Yoshida, Takeshi; Tamura, Takuya; Nagai, Yuhki; Ueda, Hiroyuki; Awaya, Tomonari; Shibata, Minoru; Kato, Takeo; Heike, Toshio

    2013-11-01

    We report a 2-year-old Japanese boy with acute necrotizing encephalopathy (ANE) triggered by human herpes virus-6, who presented insightful magnetic resonance imaging (MRI) findings. He was admitted due to impaired consciousness and a convulsion, 2 days after the onset of an upper respiratory infection. At admission, cranial MRI showed marked gadolinium enhancement at the bilateral thalami, brainstem and periventricular white matter without abnormal findings in noncontrast MRI sequences. On the following day, noncontrast computed tomography demonstrated homogeneous low-density lesions in the bilateral thalami and severe diffuse brain edema. The patient progressively deteriorated and died on the 18th day of admission. The pathogenesis of ANE remains mostly unknown, but it has been suggested that hypercytokinemia may play a major role. Overproduced cytokines cause vascular endothelial damage and alter the permeability of the vessel wall in the multiple organs, including the brain. The MRI findings in our case demonstrate that blood-brain barrier permeability was altered prior to the appearance of typical neuroradiological findings. This suggests that alteration of blood-brain barrier permeability is the first step in the development of the brain lesions in ANE, and supports the proposed mechanism whereby hypercytokinemia causes necrotic brain lesions. This is the first report demonstrating MRI gadolinium enhancement antecedent to typical neuroradiological findings in ANE.

  5. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

    NASA Astrophysics Data System (ADS)

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-01

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy

  6. The role of gadolinium chelates in the mechanism of nephrogenic systemic fibrosis: A critical update.

    PubMed

    Idée, Jean-Marc; Fretellier, Nathalie; Robic, Caroline; Corot, Claire

    2014-11-01

    Nephrogenic systemic fibrosis (NSF) is an iatrogenic scleroderma-like fibrosing systemic disorder occurring in patients with severe or end-stage renal disease. It was established as a new clinical entity in the year 2000. A causal role for gadolinium chelates (GC), widely used as contrast agents for magnetic resonance imaging, was suggested six years later. It rapidly appeared that the occurrence of NSF was associated with prior administration of GCs with lower thermodynamic stability, leading to warnings being published by health authorities and learned societies worldwide. Although a role for the chelated form of the less stable GCs has been proposed, the most commonly accepted hypothesis involves the gradual release of dissociated gadolinium in the body, leading to systemic fibrosis. However, the entire chain of events is still not fully understood in a causal way and many uncertainties remain.

  7. Tissue deposition of gadolinium and development of NSF: a convergence of factors.

    PubMed

    Perazella, Mark A

    2008-01-01

    Gadolinium-based contrast (GBC) exposure has recently been linked to the development of nephrogenic systemic fibrosis (NSF) in patients with underlying kidney disease and may in fact be the previously unrecognized trigger for the fibrosing process. As NSF is fairly rare in this patient population, a number of permissive factors are likely required for GBC exposure to initiate fibrosis. Advanced kidney disease is an absolute requirement whereas vascular injury and an inflammatory state, and a mix of co-factors including increased serum phosphate and calcium concentrations and iron overload further enhance risk. The combination of these events allows excess circulating gadolinium, which dissociates from its chelate to leak out of vessels and deposit in tissues. Free or bound tissue gadolinium, a rare earth metal of the lanthanoid series, promotes fibrosis via either direct binding to the collagen helix or, once the metal has been engulfed by macrophages, through the production of free oxygen radicals, cytokines, and other profibrotic factors that attract circulating fibrocytes to tissues. These fibrocytes then differentiate into fibroblast-like spindle cells that produce connective tissue matrix and other angiogenic and growth factors that further enhance tissue fibrosis. Direct gadolinium activation of transglutaminases on these tissue fibroblast-like cells may also promote fibrosis.

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

    PubMed

    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.

  9. Extraction-chromatographic affinage in gadolinium-153 preparation production technology

    SciTech Connect

    Melnik, M.I.; Karelin, E.A.; Kuznetsov, R.A.

    1993-12-31

    The gadolinium 153 preparation is used for production of medical gamma-sources which are applicable in bone densimeters for early diagnostics of osteoporosis. This preparation must meet strict requirements with respect to the content of europium radionuclides and specific activity. In The Research Institute of Atomic Reactors (RIAR) the gadolinium 153 is produced by neutron irradiation of Europium 151. This process is described.

  10. Resonance parameter measurements and analysis of gadolinium

    SciTech Connect

    Leinweber, G.; Barry, D. P.; Trbovich, M. J.; Burke, J. A.; Drindak, N. J.; Knox, H. D.; Ballad, R. V.; Block, R. C.; Danon, Y.; Severnyak, L. I.

    2006-07-01

    The purpose of the present work is to measure the neutron cross sections of gadolinium accurately. Gd has the highest thermal absorption cross section of any natural element. Therefore it is an important element for thermal reactor applications Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Inst. (RPI) LINAC facility using metallic and liquid Gd samples. The liquid samples were isotopically-enriched in either {sup 155}Gd or {sup 157}Gd. The capture measurements were made at the 25-m flight station with a sodium iodide detector, and the transmission measurements were performed at 15- and 25-m flight stations with {sup 6}Li glass scintillation detectors. The multilevel R-matrix Bayesian code SAMMY was used to extract resonance parameters. The results of the thermal region analysis are significant. Resonance parameters for the low energy doublet, at 0.025 and 0.032 eV, are presented. The thermal (2200 m/s) capture cross section of {sup 157}Gd has been measured to be 11% smaller than that calculated from ENDF/B-VI updated through release 8. Thermal capture cross sections and capture resonance integrals for each isotope as well as elemental gadolinium are presented. In the epithermal region, natural metal samples were measured in capture and transmission. Neutron interaction data up to 300 eV have been analyzed. Substantial improvement to the understanding of gadolinium cross sections is presented, particularly above 180 eV where the ENDF resolved region for {sup 155}Gd ends. (authors)

  11. Substitution of gadolinium ethylenediaminetetraacetate with phosphites: towards gadolinium deposit in nephrogenic systemic fibrosis.

    PubMed

    Gao, Song; Chen, Mao-Long; Zhou, Zhao-Hui

    2014-01-14

    In neutral media, reactions of gadolinium ethylenediaminetetraacetates with phosphorous acid result in the formation of the mixed-ligand polymeric complex K3n[Gd(EDTA)(HPO3)]n·7nH2O () and dimeric complex Na6[Gd2(EDTA)2(HPO3)2]·2.5NaCl·21H2O () (H4EDTA = ethylenediaminetetraacetic acid) in warm solution. Further substitution with citric acid gives the monomeric gadolinium citrate with EDTA (NH4)2Na[Gd(EDTA)(H2cit)]·4H2O (). The compounds were characterized by elemental analysis, single crystal X-ray diffraction, FT-IR, ESI-MS and thermogravimetric analysis. Structural analysis indicates that three coordinated water molecules in the gadolinium ethylenediaminetetraacetate trihydrates are replaced by phosphite ions (HPO3(2-)) in the compounds and . Gadolinium atoms are octa-coordinated by EDTA and the phosphite ion, the latter links adjacent Gd-EDTA units to generate an infinite one-dimensional chain in compound and a dimeric octatomic ring in . In complex , coordinated water molecules were substituted by the α-hydroxy, α-carboxy and β-carboxy groups of citrate. Citrate is favourable for inhibiting the formation of Gd-EDTA phosphite. All the complexes are very easily soluble in water. The solution behavior of the isostructural lanthanum complexes was probed with (13)C and (31)P NMR spectra in D2O for comparison. ESI-MS analysis and recrystallization proved that complexes and dissociate to the monomeric unit of Gd-EDTA and free HPO3(2-) in aqueous solution. Substitutions of gadolinium ethylenediaminetetraacetates to and are attributed to be the cause of nephrogenic systemic fibrosis in some way.

  12. Towards modeling gadolinium-lead-borate glasses

    SciTech Connect

    Rada, S.; Ristoiu, T.; Rada, M.; Coroiu, I.; Maties, V.; Culea, E.

    2010-01-15

    Infrared spectra of gadolinium-lead-borate glasses of the xGd{sub 2}O{sub 3}.(100 - x)[3B{sub 2}O{sub 3}.PbO] system, where x = 0, 5, 10, 15, 25, 35 and 50 mol.%, have been recorded to explore the role of content of gadolinium ions behaving as glass modifier. The FTIR spectroscopy data for the xGd{sub 2}O{sub 3}.(1 - x)[3B{sub 2}O{sub 3}.PbO] glasses show the structural role of lead ions as a network-formers and of the gadolinium ions network modifiers. Adding of the rare earth ion up to 35 mol.% into the glass matrix, the IR bands characteristic to the studied glasses become sharper and more pronounced. Structural changes, as recognized by analyzing band shapes of IR spectra, revealed that Gd{sub 2}O{sub 3} causes a change from the continuous borate network to the continuous lead-borate network interconnected through Pb-O-B and B-O-B bridges and the transformation of some tetrahedral [BO{sub 4}] units into trigonal [BO{sub 3}] units. Then, gadolinium ions have affinity towards [BO{sub 3}] structural units which contain non-bridging oxygens necessary for the charge compensation because the more electronegative [BO{sub 3}] structural units were implied in the formation of B-O-Gd bonds and the transformation of glass network into a glass ceramic. We propose a possible structural model of building blocks for the formation of continuous random 3B{sub 2}O{sub 3}.PbO network glass used by density functional theory (DFT) calculations. DFT calculations show that lead atoms occupy three different sites in the proposed model. The first is coordinated with six oxygen atoms forming distorted octahedral geometries. The second lead atom has an octahedral oxygen environment and the five longer Pb-O bonds are considered as participating in the metal coordination scheme. The third lead atom has ionic character. In agreement with the results offered by the experimental FTIR data, the theoretical IR data confirm that our proposed structure is highly possible.

  13. Light deflection in gadolinium molybdate ferroelastic crystals

    NASA Astrophysics Data System (ADS)

    Staniorowski, Piotr; Bornarel, Jean

    2000-02-01

    The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i on the sample at room temperature. The A and B deflected beams do not cross each other during the icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> 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.

  14. Specific lipase-responsive polymer-coated gadolinium nanoparticles for MR imaging of early acute pancreatitis.

    PubMed

    Zhang, Hong-Wu; Wang, Li-Qin; Xiang, Qing-Feng; Zhong, Qian; Chen, Lu-Ming; Xu, Cai-Xia; Xiang, Xian-Hong; Xu, Bo; Meng, Fei; Wan, Yi-Qian; Deng, David Y B

    2014-01-01

    Currently, available methods for diagnosis of acute pancreatitis (AP) are mainly dependent on serum enzyme analysis and imaging techniques that are too low in sensitivity and specificity to accurately and promptly diagnose AP. The lack of early diagnostic tools highlights the need to search for a highly effective and specific diagnostic method. In this study, we synthesized a conditionally activated, gadolinium-containing, nanoparticle-based MRI nanoprobe as a diagnostic tool for the early identification of AP. Gadolinium diethylenetriaminepentaacetic fatty acid (Gd-DTPA-FA) nanoparticles were synthesized by conjugation of DTPA-FA ligand and gadolinium acetate. Gd-DTPA-FA exhibited low cytotoxicity and excellent biocompatibility when characterized in vitro and in vivo studies. L-arginine induced a gradual increase in the intensity of the T1-weighted MRI signal from 1 h to 36 h in AP rat models. The increase in signal intensity was most significant at 1 h, 6 h and 12 h. These results suggest that the Gd-DTPA-FA as an MRI contrast agent is highly efficient and specific to detect early AP.

  15. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T(1) contrast ability.

    PubMed

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-14

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM(-1) s(-1). Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.

  16. In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

    PubMed

    Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

    2015-01-01

    Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

  17. Biocompatible, Biodegradable, and Enzymatic-Cleavable MRI Contrast Agents for Early Detection of Bone Metastatic Breast cancer

    DTIC Science & Technology

    2013-04-01

    against de-ionized water for 96 hrs. The final products were obtained after lyophilization. The gadolinium contents in the conjugates were measured by...have raised a safety concern for the use of these imaging agents in animals, since free gadolinium is very toxic in the body.(26-29) Therefore, we...E. Ledneva, S. Karie, V. Launay-Vacher, N. Janus, G. Deray, Renal safety of gadolinium -based contrast media in patients with chronic renal

  18. The Complex Fate in Plasma of Gadolinium Incorporated into High-Density Lipoproteins Used for Magnetic Imaging of Atherosclerotic Plaques

    PubMed Central

    Barazza, Alessandra; Blachford, Courtney; Even-Or, Orli; Joaquin, Victor A.; Briley-Saebo, Karen C.; Chen, Wei; Jiang, Xian-Cheng; Mulder, Willem J. M.; Cormode, David P.; Fayad, Zahi A.; Fisher, Edward A.

    2014-01-01

    We have previously reported enhancing the imaging of atherosclerotic plaques in mice using reconstituted high density lipoproteins (HDL) as nanocarriers for the MRI contrast agent gadolinium (Gd). This study focuses on the underlying mechanisms of Gd delivery to atherosclerotic plaques. HDL, LDL, and VLDL particles containing Gd chelated to phosphatidyl ethanolamine (DTPA-DMPE) and a lipidic fluorophore were used to demonstrate the transfer of Gd-phospholipids among plasma lipoproteins in vitro and in vivo. To determine the basis of this transfer, the roles of phospholipid transfer protein (PLTP) and lipoprotein lipase (LpL) in mediating the migration of Gd-DTPA-DMPE among lipoproteins were investigated. The results indicated that neither was an important factor, suggesting that spontaneous transfer of Gd-DTPA-DMPE was the most probable mechanism. Finally, two independent mouse models were used to quantify the relative contributions of HDL and LDL reconstituted with Gd-DTPA-DMPE to plaque imaging enhancement by MR. Both sets of results suggested that Gd-DTPA-DMPE originally associated with LDL was about twice as effective as that injected in the form of Gd-HDL, and that some of Gd-HDL’s effectiveness in vivo is indirect through transfer of the imaging agent to LDL. In conclusion, the fate of Gd-DTPA-DMPE associated with a particular type of lipoprotein is complex, and includes its transfer to other lipoprotein species that are then cleared from the plasma into tissues. PMID:23617731

  19. Exceedingly small iron oxide nanoparticles as positive MRI contrast agents.

    PubMed

    Wei, He; Bruns, Oliver T; Kaul, Michael G; Hansen, Eric C; Barch, Mariya; Wiśniowska, Agata; Chen, Ou; Chen, Yue; Li, Nan; Okada, Satoshi; Cordero, Jose M; Heine, Markus; Farrar, Christian T; Montana, Daniel M; Adam, Gerhard; Ittrich, Harald; Jasanoff, Alan; Nielsen, Peter; Bawendi, Moungi G

    2017-02-28

    Medical imaging is routine in the diagnosis and staging of a wide range of medical conditions. In particular, magnetic resonance imaging (MRI) is critical for visualizing soft tissue and organs, with over 60 million MRI procedures performed each year worldwide. About one-third of these procedures are contrast-enhanced MRI, and gadolinium-based contrast agents (GBCAs) are the mainstream MRI contrast agents used in the clinic. GBCAs have shown efficacy and are safe to use with most patients; however, some GBCAs have a small risk of adverse effects, including nephrogenic systemic fibrosis (NSF), the untreatable condition recently linked to gadolinium (Gd) exposure during MRI with contrast. In addition, Gd deposition in the human brain has been reported following contrast, and this is now under investigation by the US Food and Drug Administration (FDA). To address a perceived need for a Gd-free contrast agent with pharmacokinetic and imaging properties comparable to GBCAs, we have designed and developed zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) consisting of ∼3-nm inorganic cores and ∼1-nm ultrathin hydrophilic shell. These ZES-SPIONs are free of Gd and show a high T1 contrast power. We demonstrate the potential of ZES-SPIONs in preclinical MRI and magnetic resonance angiography.

  20. The developmental history of the gadolinium chelates as intravenous contrast media for magnetic resonance.

    PubMed

    Runge, Val M; Ai, Tao; Hao, Dapeng; Hu, Xuemei

    2011-12-01

    The developmental history of the gadolinium chelates, which spans 30 years, is described, focusing, in part, on the seminal work with each of the major agents in use today. By examining this history, insight is gained into important issues of efficacy and safety, with valuable lessons to be learned from the mistakes made during this period. An overview of physicochemical characteristics and chemical structures is also provided. The review concludes with a discussion of current research directions involving this field, which is that of the intravenous contrast media for magnetic resonance, in the past 5 years.

  1. Polymers effects on synthesis of AuNPs, and Au/Ag nanoalloys: indirectly generated AuNPs and versatile sensing applications including anti-leukemic agent.

    PubMed

    Jahan, Shanaz; Mansoor, Farrukh; Kanwal, Shamsa

    2014-03-15

    Polymers either serve as shielding or capping agents to restrict the nanoparticle size. This study demonstrates the polymer depositions and their effects in synthesis and sharp stabilization of gold nanoparticles (AuNPs) and to develop gold/silver nanoalloys (Au/Ag nanoalloys). Effects of different polymers are tested to justify their role in synthesis and stability of phloroglucinol (PG) coated AuNPs and Au/Ag nanoalloys. Cationic and anionic i.e. [Polydiallyldimethylammonium](+) (PDDA), [Polyethyleneimine](+) (PEI), [Polystyrene sulfonate](2-) (PSS) and neutral polymer Polychlorotriflouroethylene (PCTFE) produce praiseworthy stable AuNPs and Au/Ag nanoalloy. To prove polymer effects characterization protocols including UV-vis, Fluorescence (PL), IR and AFM imaging are performed to fully investigate the mechanism and size characteristics of these nanoparticles/nanoalloys. In this study sharp size controlling/sheilding effects were observed particularly with cationic polymers simply through the favorable electrostatic interactions with the terminal ends of PG Potent/significant detection of doxorubicin (DOX, an antileukemic agent) via fluorescence resonance energy transfer (FRET) between PEI shielded AuNPs (AuNPEI) and DOX was achieved upto 10 pM level, while PDDA protected AuNPs facilitated the detection of ascorbic acid based on fluorescence enhancement effects in wide range (10-200 nM) and with detection limit of 200 pM. Similarly sensing performance of PEI stabilized Au/Ag nanoalloys on addition of halides (Cl(-), Br(-), I(-)) is evaluated through red shifted SPR along with continuous increase in absorbance and also through AFM. Moreover the addition of halide ions also helped the regeneration of AuNPs by taking away silver from the Au/Ag nanoalloys enabling their detections upto subnanomolar levels.

  2. Magnetic resonance knee arthrography. Enhanced contrast by gadolinium complex in the rabbit and in humans.

    PubMed

    Engel, A

    1990-01-01

    This study contains the fundamentals and the technique of the intraarticular application of an MRI contrast agent in connection with magnetic resonance imaging (MRI arthrography). It also presents the resulting clinical relevance for knee joint diagnostics. The significance of MRI arthrography is linked above all to the central question of whether or not it is possible to depict the hyaline cartilage, its surface and its thickness with the help of MRI arthrography. MRI arthrography was used for in vitro examinations of rabbit knee joint cartilage and human joint cartilage. The in vivo application was carried out in 73 patients. Apart from the metric evaluation and the assessment of the information content of the MRI image, the corresponding histologic sections were made in 20 knee joints in order to compare the cartilage surface and the thickness of the cartilage with the results in the MRI image. The optimum amount of contrast agent for visualization was determined, the uptake and clearance of the contrast agent from the cartilage were assessed, and trace elements from the cartilage were also analyzed. The examination showed that the molecular structure of the contrast agent (gadolinium-DTPA) does not prevent the uptake of the contrast agent into the matrix of the hyaline cartilage. But this process is reversible. Thus, 14 hours after the intraarticular application of the contrast agent no measurable traces of gadolinium-DTPA could be established. The intraarticular application of the contrast agent also made it possible to achieve a constant and reproducible visualization of all joint structures. This affected mainly the surface of the hyaline cartilage. The best imaging quality was achieved with intraarticular application of 30 to 40 mL of a 2 mmolar solution of gadolinium-DTPA. The technique used for the intraarticular application is the same as for the common procedures of knee joint aspiration. The clinical importance of MRI arthrography lies in the fact that

  3. Alkali metal and alkali earth metal gadolinium halide scintillators

    DOEpatents

    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.

  4. Comparison of gadolinium depletion in CASMO-4 and CASMO-3

    SciTech Connect

    Knott, D.; Edenius, M.

    1995-12-31

    Since the mid-1980s, CASMO-3 has been used to generate two-group nodal data for SIMULATE-3. Development of CASMO-3 was based on the accuracy needed to analyze {approximately} 12-month cycle lengths. Fuel designs for these annual cycles contained low gadolinium loadings in only a few pins. As cycle lengths increased from 12 to 24 months, gadolinium loadings doubled and tripled, as did the number of pins containing gadolinium. The use of heavy burnable absorber loadings has been a driving force behind the development of CASMO-4.

  5. Current state of evidence on 'off-label' therapeutic options for systemic lupus erythematosus, including biological immunosuppressive agents, in Germany, Austria and Switzerland--a consensus report.

    PubMed

    Aringer, M; Burkhardt, H; Burmester, G R; Fischer-Betz, R; Fleck, M; Graninger, W; Hiepe, F; Jacobi, A M; Kötter, I; Lakomek, H J; Lorenz, H M; Manger, B; Schett, G; Schmidt, R E; Schneider, M; Schulze-Koops, H; Smolen, J S; Specker, C; Stoll, T; Strangfeld, A; Tony, H P; Villiger, P M; Voll, R; Witte, T; Dörner, T

    2012-04-01

    Systemic lupus erythematosus (SLE) can be a severe and potentially life-threatening disease that often represents a therapeutic challenge because of its heterogeneous organ manifestations. Only glucocorticoids, chloroquine and hydroxychloroquine, azathioprine, cyclophosphamide and very recently belimumab have been approved for SLE therapy in Germany, Austria and Switzerland. Dependence on glucocorticoids and resistance to the approved therapeutic agents, as well as substantial toxicity, are frequent. Therefore, treatment considerations will include 'off-label' use of medication approved for other indications. In this consensus approach, an effort has been undertaken to delineate the limits of the current evidence on therapeutic options for SLE organ disease, and to agree on common practice. This has been based on the best available evidence obtained by a rigorous literature review and the authors' own experience with available drugs derived under very similar health care conditions. Preparation of this consensus document included an initial meeting to agree upon the core agenda, a systematic literature review with subsequent formulation of a consensus and determination of the evidence level followed by collecting the level of agreement from the panel members. In addition to overarching principles, the panel have focused on the treatment of major SLE organ manifestations (lupus nephritis, arthritis, lung disease, neuropsychiatric and haematological manifestations, antiphospholipid syndrome and serositis). This consensus report is intended to support clinicians involved in the care of patients with difficult courses of SLE not responding to standard therapies by providing up-to-date information on the best available evidence.

  6. Contrast agents for MRI.

    PubMed

    Shokrollahi, H

    2013-12-01

    Contrast agents are divided into two categories. The first one is paramagnetic compounds, including lanthanides like gadolinium, which mainly reduce the longitudinal (T1) relaxation property and result in a brighter signal. The second class consists of super-paramagnetic magnetic nanoparticles (SPMNPs) such as iron oxides, which have a strong effect on the transversal (T2) relaxation properties. SPMNPs have the potential to be utilized as excellent probes for magnetic resonance imaging (MRI). For instance, clinically benign iron oxide and engineered ferrite nanoparticles provide a good MRI probing capability for clinical applications. Furthermore, the limited magnetic property and inability to escape from the reticuloendothelial system (RES) of the used nanoparticles impede their further advancement. Therefore, it is necessary to develop the engineered magnetic nanoparticle probes for the next-generation molecular MRI. Considering the importance of MRI in diagnosing diseases, this paper presents an overview of recent scientific achievements in the development of new synthetic SPMNP probes whereby the sensitive and target-specific observation of biological events at the molecular and cellular levels is feasible.

  7. Regression of gadolinium-enhanced lesions in patients affected by neurofibromatosis type 1.

    PubMed

    Lucchetta, Marta; Manara, Renzo; Perilongo, Giorgio; Clementi, Maurizio; Trevisson, Eva

    2016-03-01

    Neurofibromatosis type I is a genetic condition with an autosomal dominant transmission characterized by neurocutaneous involvement and a predisposition to tumor development. Central nervous system manifestations include benign areas of dysmyelination and possibly hazardous glial tumors whose clinical management may result challenging. Here, we report on three patients diagnosed with Neurofibromatosis type I whose brain MRI follow-up showed the presence of gadolinium-enhancing lesions which spontaneously regressed. In none of the three cases, the lesions showed any clinical correlate and eventually presented a striking reduction in size while gadolinium enhancement disappeared despite no specific therapy administration during the follow-up. Although their nature remains undetermined, these lesions presented a benign evolution. However, they might be misdiagnosed as potentially life-threatening tumors. Hitherto, a similar behavior has been described only in scattered cases and we believe these findings may be of particular interest for the clinical management of patients affected by neurofibromatosis type I.

  8. Speciation of gadolinium in surface water samples and plants by hydrophilic interaction chromatography hyphenated with inductively coupled plasma mass spectrometry.

    PubMed

    Lindner, Uwe; Lingott, Jana; Richter, Silke; Jakubowski, Norbert; Panne, Ulrich

    2013-02-01

    Hydrophilic interaction chromatography (HILIC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was optimized for speciation analysis of gadolinium-based contrast agents in environmental samples, in particular surface river waters and plants. Surface water samples from the Teltow channel, near Berlin, were investigated over a distance of 5 km downstream from the influx of a wastewater treatment plant. The total concentration of gadolinium increased significantly from 50 to 990 ng L(-1) due to the influx of the contrast agents. After complete mixing with the river water, the concentration remained constant over a distance of at least 4 km. Two main substances [Dotarem(®) (Gd-DOTA) and Gadovist(®) (Gd-BT-DO3A)] have been identified in the river water using standards. A gadolinium-based contrast agent, possibly Gd-DOTA (Dotarem(®)), was also detected in water plant samples taken from the Teltow channel. Therefore, uptake of contrast agents [Gadovist(®) (Gd-BTDO3A), Magnevist(®) (Gd-DTPA), Omniscan(®) (Gd-DTPA-BMA), Dotarem(®) (Gd-DOTA), and Multihance(®) (Gd-BOPTA)] by plants was investigated in a model experiment using Lepidium sativum (cress plants). HILIC-ICP-MS was used for identification of different contrast agents, and a first approach for quantification using aqueous standard solutions was tested. For speciation analysis, all investigated contrast agents could be extracted from the plant tissues with a recovery of about 54 % for Multihance(®) (Gd-BOPTA) up to 106 % for Gadovist(®) (Gd-BT-DO3A). These experiments demonstrate that all contrast agents investigated are transported from the roots to the leaves where the highest content was measured.

  9. Characterization of gadolinium and lanthanum oxide films on Si (100)

    NASA Astrophysics Data System (ADS)

    Wu, X.; Landheer, D.; Sproule, G. I.; Quance, T.; Graham, M. J.; Botton, G. A.

    2002-05-01

    High-resolution transmission electron microscopy, electron energy loss spectroscopy, and Auger electron spectroscopy, were used to study gadolinium and lanthanum oxide films deposited on Si (100) substrates using electron-beam evaporation from pressed-powder targets. As-deposited films consist of a crystalline oxide layer and an amorphous interfacial layer. A complicated distinct multilayer structure consisting of oxide layers, silicate layers, and SiO2-rich layers in thick (~30 nm) annealed films has been observed for both gadolinium and lanthanum films. For thinner annealed films (~8 nm), there is no longer a crystalline oxide layer but an amorphous gadolinium or lanthanum silicate layer and an interfacial SiO2-rich layer. The formation of the lanthanum silicate by annealing lanthanum oxide is found to be thermodynamically more favorable than the formation of gadolinium silicate.

  10. Gadolinium loaded plastic scintillators for high efficiency neutron detection

    NASA Astrophysics Data System (ADS)

    Ovechkina, Lena; Riley, Kent; Miller, Stuart; Bell, Zane; Nagarkar, Vivek

    2009-08-01

    Gadolinium has the highest thermal neutron absorption cross section of any naturally occurring element, and emits conversion electrons as well as atomic X-rays in over 50% of its neutron captures, which makes it a useful dopant in scintillators for detecting thermal neutrons. Gadolinium isopropoxide was studied as a possible dopant for styrene-based plastic scintillators as a convenient and inexpensive method to produce high-efficiency thermal neutron detectors. Plastic scintillators with gadolinium weight concentrations of up to 3% were transparent, uniform and defect-free and were characterized with spectral measurements performed under x-ray and neutron irradiation. The new material has the same characteristic emission of styrene with a maximum at approximately 425 nm, and a light output of 76% relative to the undoped plastic. A 13 mm thick sample containing 0.5% gadolinium by weight detected 46% of incident thermal neutrons, which makes this an attractive material for a variety of applications.

  11. Intraindividual comparison of gadolinium- and iodine-enhanced 64-slice multidetector CT pulmonary angiography for the detection of pulmonary embolism in a porcine model.

    PubMed

    Henes, Frank Oliver Gerhard; Groth, Michael; Begemann, Philipp G C; Adam, Gerhard; Regier, Marc

    2011-06-01

    This study is an evaluation of the diagnostic accuracy of gadolinium-enhanced computed tomography pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE) in comparison with iodine-enhanced CTPA. PE was induced in five anesthetized pigs by administration of blood clots through an 11-F catheter inside the jugular vein. Animals underwent CTPA in breathhold with i.v. bolus injection of 50 ml gadopentetate dimeglumine (0.4 mmol/kg, 4 ml/s). Subsequently, CTPA was performed using the same imaging parameters but under administration of 70 ml nonionic iodinated contrast material (400 mg/ml, 4 ml/s). All images were reconstructed with 1 mm slice thickness. A consensus readout of the iodium-enhanced CTPAs by both radiologists served as reference standard. Gadolinium-enhanced CTPAs were evaluated independently by two experienced radiologists, and differences in detection rate between both contrast agents were assessed on a per embolus basis using the Wilcoxon signed-rank test. Interobserver agreement was determined by calculation of қ values. PE was diagnosed independently by both readers in all five pigs by the use of gadolinium-enhanced CTPA. Out of 60 pulmonary emboli detected in the iodine-enhanced scans, 47 (78.3%; reader 1) and 44 (62.8%; reader 2) emboli were detected by the use of gadolinium. All 13 (100%) emboli in lobar arteries (by both readers) and 26 (reader 1) and 25 (reader 2) out of 27 emboli (96.3% and 92.6%) in segmental arteries were detected by the use of the gadolinium-enhanced CTPA. In subsegmental arteries, only 8 (40%; reader 1) and 6 (30%; reader 2) out of 20 emboli were detected by the gadolinium-enhanced CTPA. By comparing both scans on a per vessel basis (Wilcoxon test), Gd-enhanced CTPA was significantly inferior in emboli detection on subsegmental level (P < 0.0001). The interobserver agreement was excellent on lobar and segmental level (қ = 1.0 and 0.93, respectively), whereas readers only reached moderate

  12. Gadoxate disodium: gadolinium EOB DTPA, gadoxetic acid, Gd-EOB-DTPA.

    PubMed

    2004-01-01

    Gadoxate disodium [gadolinium EOB DTPA, Gd-EOB-DTPA, gadoxetic acid, Eovist injection, Primovist] is a hydrophilic paramagnetic contrast agent being developed by Schering AG for hepatobiliary magnetic resonance imaging. In April 2004, gadoxate disodium (Primovist) was approved in Sweden, the reference member state for the EU registration. Following the Swedish approval, Schering will initiate a mutual recognition procedure for the EU with approvals expected in most countries during 2004. Gadoxate disodium is in phase III clinical trials in the US and has completed phase III studies in Japan. Submissions for approval in Japan and other Asian countries are planned for 2004. Schering AG plans to launch Eovist in Japan in 2005. Schering AG acquired a worldwide, royalty-bearing licence to EPIX Medical's patents covering liver-enhancing agents such as Eovist injection. These included a European patent (222886) and the US patents (4,899,755 and 4,888,008) that EPIX Medical exclusively licensed from the Massachusetts General Hospital (MGH). The MGH patents, a part of EPIX's extensive intellectual property, also covered albumin-targeted agents such as MS 325 (AngioMARK). Schering AG formally withdrew from the opposition proceedings against EPIX's EU patent 222886 following its acquisition of EPIX's intellectual property. These EU and US patents were also non-exclusively licensed by EPIX Medical to Bracco in September 2001. Apart from covering Eovist (Schering AG), the EU patent also covered gadobenate dimeglumine (MultiHance Bracco). Following the licensing agreement, Bracco withdrew its opposition to the patents in Europe and Japan, and both EPIX Medical and Bracco settled their European patent dispute. In its 2002 Annual Report, Schering predicted that Eovist has the potential to reach peak sales of euro50 million, three years after launch--at the time, launch in Europe was anticipated in 2004, followed by launch in Japan in 2005. This is down from earlier predictions

  13. Nanodiamond-Gadolinium(III) Aggregates for Tracking Cancer Growth In Vivo at High Field.

    PubMed

    Rammohan, Nikhil; MacRenaris, Keith W; Moore, Laura K; Parigi, Giacomo; Mastarone, Daniel J; Manus, Lisa M; Lilley, Laura M; Preslar, Adam T; Waters, Emily A; Filicko, Abigail; Luchinat, Claudio; Ho, Dean; Meade, Thomas J

    2016-12-14

    The ability to track labeled cancer cells in vivo would allow researchers to study their distribution, growth, and metastatic potential within the intact organism. Magnetic resonance (MR) imaging is invaluable for tracking cancer cells in vivo as it benefits from high spatial resolution and the absence of ionizing radiation. However, many MR contrast agents (CAs) required to label cells either do not significantly accumulate in cells or are not biologically compatible for translational studies. We have developed carbon-based nanodiamond-gadolinium(III) aggregates (NDG) for MR imaging that demonstrated remarkable properties for cell tracking in vivo. First, NDG had high relaxivity independent of field strength, a finding unprecedented for gadolinium(III) [Gd(III)]-nanoparticle conjugates. Second, NDG demonstrated a 300-fold increase in the cellular delivery of Gd(III) compared to that of clinical Gd(III) chelates without sacrificing biocompatibility. Further, we were able to monitor the tumor growth of NDG-labeled flank tumors by T1- and T2-weighted MR imaging for 26 days in vivo, longer than was reported for other MR CAs or nuclear agents. Finally, by utilizing quantitative maps of relaxation times, we were able to describe tumor morphology and heterogeneity (corroborated by histological analysis), which would not be possible with competing molecular imaging modalities.

  14. Bioconjugation of luminescent silicon quantum dots to gadolinium ions for bioimaging applications.

    PubMed

    Erogbogbo, Folarin; Chang, Ching-Wen; May, Jasmine L; Liu, Liwei; Kumar, Rajiv; Law, Wing-Cheung; Ding, Hong; Yong, Ken Tye; Roy, Indrajit; Sheshadri, Mukund; Swihart, Mark T; Prasad, Paras N

    2012-09-07

    Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd³⁺) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd³⁺. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they maintain their optical properties within the intracellular environment. The magnetic resonance relaxivity of the nanoconstruct was 2.4 mM⁻¹ s⁻¹ (in terms of Gd³⁺ concentration), calculated to be around 6000 mM⁻¹ s⁻¹ per nanoconstruct. These desirable optical and relaxivity properties of the newly developed probe open the door for use of SiQDs in future multimodal applications such as tumour imaging.

  15. Characterizing Prostiva RF treatments of the prostate for BPH with gadolinium-enhanced MRI.

    PubMed

    Huidobro, Christian; Larson, Benjamin; Mynderse, Samuel; Myers, James J; Busel, David; Acevedo, Cristian; Larson, Thayne R; Mynderse, Lance A

    2009-01-18

    Transurethral needle ablation (TUNA) is an accepted and effective therapy for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Prostiva (Medtronic, Shoreview, MN) is the newest-generation device, which includes a new needle design and radio frequency (RF) generator. This device creates temperatures of 120 degrees C and necrotic lesions in less than 2.5 min. Using previously described techniques, we analyzed dynamic, gadolinium-enhanced MRIs to characterize the ablative properties of the new Prostiva RF device. Ten men with LUTS due to BPH were treated with the standard Prostiva manufacturer-recommended protocol. The bladder neck and lateral lobes received treatment based on prostate volume and prostatic urethral length. Gadolinium-enhanced MRI sequences were obtained prior to and 1 week post-treatment. Analyze software (Mayo Clinic Biomedical Imaging Resource, Rochester, MN) was used to evaluate MRIs. New gadolinium defects were seen in all patients following Prostiva treatments. All lesions coalesced within the prostate. No defects were seen beyond the prostate, and the urethra was spared in all patients. The mean volume of necrosis was 7.56 cc, representing a mean of 11.28% of total prostate volume. Dynamic, gadolinium-enhanced MRIs demonstrate new vascular defects representing necrosis caused by Prostiva RF therapy of the prostate. The standard Prostiva RF protocol produces lesions that coalesce to create larger lesions in the bladder neck and lateral lobes. Compared to the TUNA Precision Plus device, the ablative lesions appear comparable while produced with a shorter burn time.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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.

  17. Long-term in vivo clearance of gadolinium-based AGuIX nanoparticles and their biocompatibility after systemic injection.

    PubMed

    Sancey, Lucie; Kotb, Shady; Truillet, Charles; Appaix, Florence; Marais, Arthur; Thomas, Eloïse; van der Sanden, Boudewijn; Klein, Jean-Philippe; Laurent, Blandine; Cottier, Michèle; Antoine, Rodolphe; Dugourd, Philippe; Panczer, Gérard; Lux, François; Perriat, Pascal; Motto-Ros, Vincent; Tillement, Olivier

    2015-03-24

    We previously reported the synthesis of gadolinium-based nanoparticles (NPs) denoted AGuIX (activation and guiding of irradiation by X-ray) NPs and demonstrated their potential as an MRI contrast agent and their efficacy as radiosensitizing particles during X-ray cancer treatment. Here we focus on the elimination kinetics of AGuIX NPs from the subcellular to whole-organ scale using original and complementary methods such as laser-induced breakdown spectroscopy (LIBS), intravital two-photon microscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), and electrospray ionization mass spectrometry (ESI-MS). This combination of techniques allows the exact mechanism of AGuIX NPs elimination to be elucidated, including their retention in proximal tubules and their excretion as degraded or native NPs. Finally, we demonstrated that systemic AGuIX NP administration induced moderate and transient effects on renal function. These results provide useful and promising preclinical information concerning the safety of theranostic AGuIX NPs.

  18. Whole-Genome Sequence of Pseudomonas fluorescens EK007-RG4, a Promising Biocontrol Agent against a Broad Range of Bacteria, Including the Fire Blight Bacterium Erwinia amylovora

    PubMed Central

    Habibi, Roghayeh; Tarighi, Saeed; Behravan, Javad; Taheri, Parissa; Kjøller, Annelise Helene; Brejnrod, Asker; Madsen, Jonas Stenløkke

    2017-01-01

    ABSTRACT Here, we report the first draft whole-genome sequence of Pseudomonas fluorescens strain EK007-RG4, which was isolated from the phylloplane of a pear tree. P. fluorescens EK007-RG4 displays strong antagonism against Erwinia amylovora, the causal agent for fire blight disease, in addition to several other pathogenic and non-pathogenic bacteria. PMID:28360179

  19. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes

    NASA Astrophysics Data System (ADS)

    Abrikossova, Natalia; Skoglund, Caroline; Ahrén, Maria; Bengtsson, Torbjörn; Uvdal, Kajsa

    2012-07-01

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

  20. PARTITIONING OF GADOLINIUM IN THE CHEMICAL PROCESSING CELL

    SciTech Connect

    Reboul, S.; Best, D.; Stone, M.; Click, D.

    2011-04-27

    A combination of short-term beaker tests and longer-duration Sludge Receipt and Adjustment Tank (SRAT) simulations were performed to investigate the relative partitioning behaviors of gadolinium and iron under conditions applicable to the Chemical Processing Cell (CPC). The testing was performed utilizing non-radioactive simple Fe-Gd slurries, non-radioactive Sludge Batch 6 simulant slurries, and a radioactive real-waste slurry representative of Sludge Batch 7 material. The testing focused on the following range of conditions: (a) Fe:Gd ratios of 25-100; (b) pH values of 2-6; (c) acidification via addition of nitric, formic, and glycolic acids; (d) temperatures of {approx}93 C and {approx}22 C; and (e) oxalate concentrations of <100 mg/kg and {approx}10,000 mg/kg. The purpose of the testing was to provide data for assessing the potential use of gadolinium as a supplemental neutron poison when dispositioning excess plutonium. Understanding of the partitioning behavior of gadolinium in the CPC was the first step in assessing gadolinium's potential applicability. Significant fractions of gadolinium partitioned to the liquid-phase at pH values of 4.0 and below, regardless of the Fe:Gd ratio. In SRAT simulations targeting nitric and formic acid additions of 150% acid stoichiometry, the pH dropped to a minimum of 3.5-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were both {approx}20%. In contrast, in a SRAT simulation utilizing a nitric and formic acid addition under atypical conditions (due to an anomalously low insoluble solids content), the pH dropped to a minimum of 3.7, and the maximum fractions of gadolinium and iron partitioning to solution were {approx}60% and {approx}70%, respectively. When glycolic acid was used in combination with nitric and formic acids at 100% acid stoichiometry, the pH dropped to a minimum of 3.6-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were 60-80% and 3-5%, respectively

  1. [General adverse reactions to contrast agents. Classification and general concepts].

    PubMed

    Aguilar García, J J; Parada Blázquez, M J; Vargas Serrano, B; Rodríguez Romero, R

    2014-06-01

    General adverse reactions to intravenous contrast agents are uncommon, although relevant due to the growing number of radiologic tests that use iodinated or gadolinium-based contrast agents. Although most of these reactions are mild, some patients can experience significant reactions that radiologists should know how to prevent and treat.

  2. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    SciTech Connect

    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.

  3. Drosophila modifier screens to identify novel neuropsychiatric drugs including aminergic agents for the possible treatment of Parkinson’s disease and depression

    PubMed Central

    Lawal, Hakeem O.; Terrell, Ashley; Lam, Hoa A.; Djapri, Christine; Jang, Jennifer; Hadi, Richard; Roberts, Logan; Shahi, Varun; Chou, Man-Ting; Biedermann, Traci; Huang, Brian; Lawless, George M.; Maidment, Nigel T.; Krantz, David E.

    2012-01-01

    Small molecules that increase the presynaptic function of aminergic cells may provide neuroprotection in Parkinson’s disease as well as treatments for attention deficit hyperactivity disorder (ADHD) and depression. Model genetic organisms such as Drosophila melanogaster may enhance the detection of new drugs via modifier or “enhancer/suppressor” screens, but this technique has not been applied to processes relevant to psychiatry. To identify new aminergic drugs in vivo, we used a mutation in the Drosophila vesicular monoamine transporter (dVMAT) as a sensitized genetic background, and performed a suppressor screen. We fed dVMAT mutant larvae ~1000 known drugs and quantitated rescue (suppression) of an amine-dependent locomotor deficit in the larva. To determine which drugs might specifically potentiate neurotransmitter release, we performed an additional secondary screen for drugs that require presynaptic amine storage to rescue larval locomotion. Using additional larval locomotion and adult fertility assays, we validated that at least one compound previously used clinically as an antineoplastic agent potentiates the presynaptic function of aminergic circuits. We suggest that structurally similar agents might be used to development treatments for Parkinson’s disease, depression and ADHD and that modifier screens in Drosophila provide a new strategy to screen for neuropsychiatric drugs. More generally, our findings demonstrate the power of physiologically based screens for identifying bioactive agents for select neurotransmitter systems. PMID:23229049

  4. Gadolinium metallo nanocongregates as potential magnetosensors for detecting early stage cancers

    SciTech Connect

    Dutta, Ranu; Pandey, Avinash C.

    2015-04-27

    Gadolinium chelates and gadolinium based inorganic nanoparticles have been extensively studied, because of the high magnetic moment of gadolinium. Here, metallic gadolinium nanocongregates have been developed. Upon injecting these nanoparticles in the mice, they initially circulate in the blood stream and are localized at the cancer site, which could be visualized upon application of magnetic field hence acting as small magnetic nanosensors searching for even small cancers, detecting cancers at a very early stage.

  5. Evaluation of gadolinium compounds potentially suitable for magnetic resonance using Gd-153 scintigraphy

    SciTech Connect

    Engelstad, B.; Huberty, J.; White, D.; Wynne, C.; Ramos, E.; Goldberg, H.

    1985-05-01

    Gd-153 is not customarily considered for scintigraphy, yet it: 1) is available at acceptable cost, 2) has a 242 day half-life suitable for prolonged animal studies and 3) has 97 keV (40%) and 103 keV (59%) photopeaks suitable for conventional scintigraphy. Gd-153 (10-15 ..mu..Ci; 370-555 kBq) was administered to normal rats in 5 forms: 1) carrier 0.1 mmole/kg Gd-EIDA (diethyl iminodiacetic acid), 2) tracer (<.1 umole/kg) Gd-EIDA, 3) tracer Gd-ISIDA (diisopropyl iminodiacetic acid), 4) tracer GdCl/sub 3/, and 5) tracer Gd-DTPA. Scintigraphy, performed continuously for 90 minutes following intravenous injection and at intervals at up to 2 weeks, depicted: 1) rapid, partial hepatobiliary and renal clearance of tracer Gd-EIDA and Gd-ISIDA; 2) slow blood clearance and partial hepatobiliary clearance of carrier Gd-EIDA; and 3) prolonged reticuloendothelial retention of all IDA complexes, similar to GdCl3. Whole body and tissue distribution data paralleled the scintigraphic findings. Gd-153 scintigraphy provides a simple method to assess balance, distribution, kinetics, and stability of new paramagnetic contrast agents, and bis-iminodiacetate gadolinium complexes, unlike technetium analogues, lack effective stability to prevent gadolinium hydrolysis or translocation.

  6. Microcalorimetric studies on the energy release of isolated rat mitochondria under different concentrations of gadolinium (III).

    PubMed

    Zhao, Jie; Ma, Long; Xiang, Xun; Guo, Qing-Lian; Jiang, Feng-Lei; Liu, Yi

    2016-06-01

    Gadolinium-based compounds are most widely utilized for paramagnetic contrast agents, but, the toxicological mechanism of gadolinium (Gd) had not been fully elucidated since the first report about Gd anomaly. In this work, we analyzed the effect of Gd(3+) on mitochondria in vitro by microcalorimetry. Microcalorimetry can provide detailed kinetic and thermodynamic information from thermogenic curve. At the tested concentration, Gd(3+) induced the increase of growth rate constant (k1). At high concentration (100-500 μM), the maximum power output time (tm), the decline rate constant (-k2) and the time of activity recovery phase (tR) decreased with the addition of Gd(3+) and the maximum power output (Pm) increased. At low concentration (0-100 μM), the changes were different from high concentration. From the results we concluded that the effect of different concentrations of Gd(3+) had a relationship with time, high concentration of Gd(3+) induced mitochondrial energy metabolism disturb however low concentration may promote mitochondrial adaption to physiological stresses. The effect of low concentration of Gd(3+) need more work to elucidate the mechanism. The results of total heat output (Q) and mitochondrial respiratory activities suggested high concentrations of Gd(3+) could accelerate adenosine triphosphate (ATP) consumption under respiratory system damaged.

  7. Nanoparticles for multi-modality cancer diagnosis: Simple protocol for self-assembly of gold nanoclusters mediated by gadolinium ions.

    PubMed

    Hou, Wenxiu; Xia, Fangfang; Alfranca, Gabriel; Yan, Hao; Zhi, Xiao; Liu, Yanlei; Peng, Chen; Zhang, Chunlei; de la Fuente, Jesus Martinez; Cui, Daxiang

    2017-03-01

    It is essential to develop a simple synthetic strategy to improve the quality of multifunctional contrast agents for cancer diagnosis. Herein, we report a time-saving method for gadolinium (Gd(3+)) ions-mediated self-assembly of gold nanoclusters (GNCs) into monodisperse spherical nanoparticles (GNCNs) under mild conditions. The monodisperse, regular and colloidal stable GNCNs were formed via selectively inducing electrostatic interactions between negatively-charged carboxylic groups of gold nanoclusters and trivalent cations of gadolinium in aqueous solution. In this way, the Gd(3+) ions were chelated into GNCNs without the use of molecular gadolinium chelates. With the co-existence of GNCs and Gd(3+) ions, the formed GNCNs exhibit significant luminescence intensity enhancement for near-infrared fluorescence (NIRF) imaging, high X-ray attenuation for computed tomography (CT) imaging and reasonable r1 relaxivity for magnetic resonance (MR) imaging. The excellent biocompatibility of the GNCNs was proved both in vitro and in vivo. Meanwhile, the GNCNs also possess unique NIRF/CT/MR imaging ability in A549 tumor-bearing mice. In a nutshell, the simple and safe GNCNs hold great potential for tumor multi-modality clinical diagnosis.

  8. Relaxivity enhancement of aquated Tris(β-diketonate)gadolinium(III) chelates by confinement within ultrashort single-walled carbon nanotubes.

    PubMed

    Law, Justin J; Guven, Adem; Wilson, Lon J

    2014-01-01

    Ultrashort single-walled carbon nanotubes loaded with gadolinium ions (gadonanotubes) have been previously shown to exhibit extremely high T1 -weighted relaxivities (>100 mm(-1) s(-1) ). To further examine the effect of nanoconfinement on the relaxivity of gadolinium-based contrast agents for magnetic resonance imaging, a series of ultrashort single-walled carbon nanotube (US-tube) materials internally loaded with gadolinium chelates have been prepared and studied. US-tubes were loaded with Gd(acac)3  · 2H2 O, Gd(hfac)3  · 2H2 O, and Gd(thd)3 (acac = acetylacetone, hfac = hexafluoroacetylacetone, thd = tetramethylheptanedione). The longitudinal relaxivities of the prepared materials determined at 25°C in a 1.5 T field were 103 mm(-1) s(-1) for Gd(acac)3  · 2H2 O@US-tubes, 105 mm(-1) s(-1) for Gd(hfac)3  · 2H2 O@US-tubes and 26 mm(-1) s(-1) for Gd(thd)3 @US-tubes. Compared with the relaxivities obtained for the unloaded chelates (<10 mm(-1) s(-1) ) as well as accounting for the T1 reduction observed for the empty US-tubes, the boost in relaxivity for chelate-loaded US-tubes is attributed to confinement within the nanotube and depends on the number of coordinated water molecules.

  9. Rhenium analogues of promising renal imaging agents with a [99mTc(CO)3]+ core bound to cysteine-derived dipeptides, including lanthionine.

    PubMed

    He, Haiyang; Lipowska, Malgorzata; Xu, Xiaolong; Taylor, Andrew T; Marzilli, Luigi G

    2007-04-16

    The coordination chemistry of lanthionine (LANH2) and cystathionine (CSTH2) dipeptides, which respectively consist of two cysteines and one cysteine and one homocysteine linked by a thioether bridge, is almost unstudied. Recently for fac-[99mTc(CO)3(LAN)]- isomers, the first small 99mTc(CO)3 agents evaluated in humans were found to give excellent renal images and to have a high specificity for renal excretion. Herein we report the synthesis and characterization of Re complexes useful for interpreting the nature of tracer 99mTc radiopharmaceuticals. Treatment of [Re(CO)3(H2O)3]OTf with commercially available LANH2 (a mixture of meso (d,l) and chiral (dd,ll) isomers) gave three HPLC peaks, 1A, 1B, and 1C, but treatment with CSTH2 (l,l isomer) gave one major product, Re(CO)3(CSTH) (2). Crystalline Re(CO)3(LANH) products were best obtained with synthetic LANH2, richer in meso or chiral isomers. X-ray crystallography showed that these dipeptides coordinate as tridentate N2S-bound ligands with two dangling carboxyls. The LANH ligand is meso in 1A and 1C and chiral in 1B. While 1A (kinetically favored) is stable at ambient temperature for days, it converted into 1C (thermodynamically favored) at 100 degrees C; after 6 h, equilibrium was reached at a 1A:1C ratio of 1:2 at pH 8. The structures provide a rationale for this behavior and for the fact that 1A and 1C have simple NMR spectra. This simplicity results from fluxional interchange between an enantiomer with both chelate rings having the same delta pucker and an enantiomer with both chelate rings having the same lambda pucker. Agents with the [99mTc(CO)3]+ core and N2S ligands show promise of becoming an important class of 99mTc radiopharmaceuticals. The chemistry of Re analogues with these ligands, such as the LAN2- complexes reported here, provides a useful background for designing new small agents and also tagged large agents because two uncoordinated carboxyl groups are available for conjugation with biological

  10. Gadolinium accumulation in organs of Sprague-Dawley® rats after implantation of a biodegradable magnesium-gadolinium alloy.

    PubMed

    Myrissa, Anastasia; Braeuer, Simone; Martinelli, Elisabeth; Willumeit-Römer, Regine; Goessler, Walter; Weinberg, Annelie Martina

    2017-01-15

    Biodegradable magnesium implants are under investigation because of their promising properties as medical devices. For enhancing the mechanical properties and the degradation resistance, rare earth elements are often used as alloying elements. In this study Mg10Gd pins were implanted into Sprague-Dawley® rats. The pin volume loss and a possible accumulation of magnesium and gadolinium in the rats' organs and blood were investigated in a long-term study over 36weeks. The results showed that Mg10Gd is a fast disintegrating material. Already 12weeks after implantation the alloy is fragmented to smaller particles, which can be found within the intramedullary cavity and the cortical bones. They disturbed the bone remodeling until the end of the study. The results concerning the elements' distribution in the animals' bodies were even more striking, since an accumulation of gadolinium could be observed in the investigated organs over the whole time span. The most affected tissue was the spleen, with up to 3240μgGd/kg wet mass, followed by the lung, liver and kidney (up to 1040, 685 and 207μgGd/kg). In the brain, muscle and heart, the gadolinium concentrations were much smaller (less than 20μg/kg), but an accumulation could still be detected. Interestingly, blood serum samples showed no accumulation of magnesium and gadolinium. This is the first time that an accumulation of gadolinium in animal organs was observed after the application of a gadolinium-containing degradable magnesium implant. These findings demonstrate the importance of future investigations concerning the distribution of the constituents of new biodegradable materials in the body, to ensure the patients' safety.

  11. High relaxivity MRI contrast agents part 2: Optimization of inner- and second-sphere relaxivity

    PubMed Central

    Jacques, Vincent; Dumas, Stephane; Sun, Wei-Chuan; Troughton, Jeffrey S.; Greenfield, Matthew T.; Caravan, Peter

    2011-01-01

    Rationale and objectives The observed relaxivity of gadolinium based contrast agents has contributions from the water molecule(s) that bind directly to the gadolinium ion (inner-sphere water), long lived water molecules and exchangeable protons that make up the second-sphere of coordination, and water molecules that diffuse near the contrast agent (outer-sphere). Inner- and second-sphere relaxivity can both be increased by optimization of the lifetimes of the water molecules and protons in these coordination spheres, the rotational motion of the complex, and the electronic relaxation of the gadolinium ion. We sought to identify new high relaxivity contrast agents by systematically varying the donor atoms that bind directly to gadolinium to increase inner-sphere relaxivity and concurrently including substituents that influence the second-sphere relaxivity. Methods Twenty GdDOTA derivatives were prepared and their relaxivity determined in presence and absence of human serum albumin as a function of temperature and magnetic field. Data was analyzed to extract the underlying molecular parameters influencing relaxivity. Each compound had a common albumin-binding group and an inner-sphere donor set comprising the 4 tertiary amine N atoms from cyclen, an α-substituted acetate oxygen atom, two amide oxygen atoms, an inner-sphere water oxygen atom, and a variable donor group. Each amide nitrogen was substituted with different groups to promote hydrogen bonding with second-sphere water molecules. Results Relaxivites at 0.47T and 1.4T, 37 °C, in serum albumin ranged from 16.0 to 58.1 mM−1s−1 and from 12.3 to 34.8 mM−1s−1 respectively. The reduction of inner-sphere water exchange typical of amide donor groups could be offset by incorporating a phosphonate or phenolate oxygen atom donor in the first coordination sphere resulting in higher relaxivity. Amide nitrogen substitution with pendant phosphonate or carboxylate groups increased relaxivity by as much as 88

  12. A feasibility study to determine the potential of in vivo detection of gadolinium by x-ray fluorescence (XRF) following gadolinium-based contrast-enhanced MRI.

    PubMed

    Mostafaei, F; McNeill, F E; Chettle, D R; Noseworthy, M D

    2015-01-01

    The feasibility of using a (109)Cd γ-ray induced K x-ray fluorescence (K-XRF) system for the in vivo detection of gadolinium (Gd) in bone has been investigated. The K-XRF bone measurement system employs an array of four detectors, and is normally used for the non-invasive study of bone lead levels. The system was used to measure bone simulating phantoms doped with varying levels of gadolinium and fixed amounts of sodium (Na), chlorine (Cl) and calcium (Ca). The detection limits for bare bone phantoms, using a source of activity 0.17 GBq, were determined to be 3.9 ppm and 6.5 ppm (µg Gd per gram phantom) for the Kα1 and Kα2 Gd x-ray peaks, respectively. This leads to an overall detection limit of 3.3 ppm (µg Gd per gram phantom). Layers of plastic were used to simulate overlying soft tissue and this permitted prediction of a detection limit, using the current strength of our radioisotope source, of 6.1 ppm to 8.6 ppm (µg Gd per gram phantom) for fingers with 2-4 mm of overlying tissue. With a new source of activity 5 GBq, we predict that this system could achieve a detection limit of 4-5.6 µg Gd g(-1) Ca. This is within the range of levels (2-30 µg Gd g(-1) Ca) previously found in the bone of patients receiving Gd based contrast imaging agents. The technique is promising and warrants further investigation.

  13. Gadolinium-Enhanced Magnetic Resonance Angiography for Pulmonary Embolism

    PubMed Central

    Stein, Paul D.; Chenevert, Thomas L.; Fowler, Sarah E.; Goodman, Lawrence R.; Gottschalk, Alexander; Hales, Charles A.; Hull, Russell D.; Jablonski, Kathleen A.; Leeper, Kenneth V.; Naidich, David P.; Sak, Daniel J.; Sostman, H. Dirk; Tapson, Victor F.; Weg, John G.; Woodard, Pamela K.

    2011-01-01

    Background The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively. Objective To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism. Design Prospective, multicenter study from 10 April 2006 to 30 September 2008. (ClinicalTrials.gov registration number: NCT00241826) Setting 7 hospitals and their emergency services. Patients 371 adults with diagnosed or excluded pulmonary embolism. Measurements Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation–perfusion lung scan, venous ultra-sonography, D-dimer assay, and clinical assessment. Results Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results. Limitation A high proportion of patients with suspected embolism was not eligible or declined to participate. Conclusion Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic

  14. Gadolinium chloride pretreatment ameliorates acute cadmium-induced hepatotoxicity.

    PubMed

    Kyriakou, Loukas G; Tzirogiannis, Konstantinos N; Demonakou, Maria D; Kourentzi, Kalliopi T; Mykoniatis, Michael G; Panoutsopoulos, Georgios I

    2013-08-01

    Cadmium is a known industrial and environmental pollutant. It causes hepatotoxicity upon acute administration. Features of cadmium-induced acute hepatoxicity encompass necrosis, apoptosis, peliosis and inflammatory infiltration. Gadolinium chloride (GdCl3) may prevent cadmium-induced hepatotoxicity by suppressing Kupffer cells. The effect of GdCl3 pretreatment on a model of acute cadmium-induced liver injury was investigated. Male Wistar rats 4-5 months old were injected intraperitoneally with normal saline followed by cadmium chloride (CdCl2; 6.5 mg/kg) or GdCl3 (10 mg/kg) followed by CdCl2 (6.5 mg/kg; groups I and II, respectively). Rats of both the groups were killed at 9, 12, 16, 24, 48 and 60 h after cadmium intoxication. Liver sections were analyzed for necrosis, apoptosis, peliosis and mitoses. Liver regeneration was also evaluated by tritiated thymidine incorporation into hepatic DNA. Serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also determined. Hepatic necrosis, hepatocyte and nonparenchymal cell apoptosis and macroscopic and microscopic types of peliosis hepatis were minimized by gadolinium pretreatment. Serum levels of AST and ALT were also greatly diminished in rats of group II. Tritiated thymidine incorporation into hepatic DNA was increased in gadolinium pretreatment rats. Kupffer cell activation was minimal in both the groups of rats. Gadolinium pretreatment attenuates acute cadmium-induced liver injury in young Wistar rats, with mechanisms other than Kupffer cell elimination.

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

    NASA Astrophysics Data System (ADS)

    Boiko, R. S.; Barabash, A. S.; Belli, P.; Bernabei, R.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.

    2014-01-01

    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.

  16. Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

    SciTech Connect

    Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

    2014-11-07

    High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperature of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.

  17. Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

    DOE PAGES

    Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; ...

    2014-11-07

    High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

  18. Getting Acquainted: An Induction Training Guide for First-Year Extension Agents. Suggestions for Completing Certain Learning Experiences Included in the Induction Training Guide; a Supplement to "Getting Acquainted."

    ERIC Educational Resources Information Center

    Collings, Mary Louise; Gassie, Edward W.

    An induction guide to help the extension agent get acquainted with his role and suggestions for completing learning experiences that are included in the guide comprise this two-part publication. The training guide learning experiences, a total of 25, are made up of: Objectives of the New Worker; When Completed; Learning Experiences; Person(s)…

  19. Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.

    PubMed

    Martino, Chiara; Bonaventura, Rosa; Byrne, Maria; Roccheri, Maria; Matranga, Valeria

    2016-06-02

    Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species. These different sensitivities highlight the importance of testing toxicity in several species for risk assessment. The strong negative effects of Gd on calcification in plutei, together with the plethora of marine species that have calcifying larvae, indicates that Gd pollution is urgent issue that needs to be addressed.

  20. Nanosystem composed with MSNs, gadolinium, liposome and cytotoxic peptides for tumor theranostics.

    PubMed

    Jin, Yaqing; Zhang, Nengpan; Li, Chunlin; Pu, Kefeng; Ding, Chen; Zhu, Yimin

    2017-03-01

    A dual-functional delivery system, based on mesoporous silica nanoparticles (MSNs) with the integration of Magnetic Resonance (MR) imaging and therapeutic peptide delivery, is reported in this paper. A lipid bilayer is attached onto the surface of the nanoparticles, following the doping of Gadolinium (Gd), a paramagnetic lanthanide ion. The liposome-coated GdMSNs exhibit improved colloidal stability, better biocompatibility and more efficient cellular uptake. The Gd renders the nano carrier a potential T1 contrast agent, confirmed by the MR imaging. A pro-apoptotic peptide, KLA (HGGKLAKLAKKLAKLAK), is encapsulated into the GdMSNs-LP and enters into the cells successfully to induce mitochondrial swelling and apoptosis, while it is nontoxic outside the cells. The synthesis procedure is convenient and free of toxic organic reagents. The nanosystem we construct may contribute to a promising theranostic platform for therapeutic peptide delivery in cancer treatment.

  1. Redox-Triggered Self-Assembly of Gadolinium-Based MRI Probes for Sensing Reducing Environment

    PubMed Central

    2014-01-01

    Controlled self-assembly of small molecule gadolinium (Gd) complexes into nanoparticles (GdNPs) is emerging as an effective approach to design activatable magnetic resonance imaging (MRI) probes and amplify the r1 relaxivity. Herein, we employ a reduction-controlled macrocyclization reaction and self-assembly to develop a redox activated Gd-based MRI probe for sensing a reducing environment. Upon disulfide reduction at physiological conditions, an acyclic contrast agent 1 containing dual Gd-chelates undergoes intramolecular macrocyclization to form rigid and hydrophobic macrocycles, which subsequently self-assemble into GdNPs, resulting in a ∼60% increase in r1 relaxivity at 0.5 T. Probe 1 has high r1 relaxivity (up to 34.2 mM–1 s–1 per molecule at 0.5 T) upon activation, and also shows a high sensitivity and specificity for MR detection of thiol-containing biomolecules. PMID:24992373

  2. A Manganese Alternative to Gadolinium for MRI Contrast.

    PubMed

    Gale, Eric M; Atanasova, Iliyana P; Blasi, Francesco; Ay, Ilknur; Caravan, Peter

    2015-12-16

    Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) are routinely used to diagnose soft tissue and vascular abnormalities. However, safety concerns limit the use of iodinated and gadolinium (Gd)-based CT and MRI contrast media in renally compromised patients. With an estimated 14% of the US population suffering from chronic kidney disease (CKD), contrast media compatible with renal impairment is sorely needed. We present the new manganese(II) complex [Mn(PyC3A)(H2O)](-) as a Gd alternative. [Mn(PyC3A)(H2O)](-) is among the most stable Mn(II) complexes at pH 7.4 (log KML = 11.40). In the presence of 25 mol equiv of Zn at pH 6.0, 37 °C, [Mn(PyC3A)(H2O)](-) is 20-fold more resistant to dissociation than [Gd(DTPA)(H2O)](2-). Relaxivity of [Mn(PyC3A)(H2O)](-) in blood plasma is comparable to commercial Gd contrast agents. Biodistribution analysis confirms that [Mn(PyC3A)(H2O)](-) clears via a mixed renal/hepatobiliary pathway with >99% elimination by 24 h. [Mn(PyC3A)(H2O)](-) was modified to form a bifunctional chelator and 4 chelates were conjugated to a fibrin-specific peptide to give Mn-FBP. Mn-FBP binds the soluble fibrin fragment DD(E) with Kd = 110 nM. Per Mn relaxivity of Mn-FBP is 4-fold greater than [Mn(PyC3A)(H2O)](-) and increases 60% in the presence of fibrin, consistent with binding. Mn-FBP provided equivalent thrombus enhancement to the state of the art Gd analogue, EP-2104R, in a rat model of arterial thrombosis. Mn metabolite analysis reveals no evidence of dechelation and the probe was >99% eliminated after 24 h. [Mn(PyC3A)(H2O)](-) is a lead development candidate for an imaging probe that is compatible with renally compromised patients.

  3. A Manganese Alternative to Gadolinium for MRI Contrast

    PubMed Central

    Gale, Eric M.; Atanasova, Iliyana P.; Blasi, Francesco; Ay, Ilknur; Caravan, Peter

    2016-01-01

    Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) are routinely used to diagnose soft tissue and vascular abnormalities. However safety concerns limit the use of iodinated and gadolinium- (Gd) based CT and MRI contrast media in renally compromised patients. With an estimated 14% of the US population suffering from chronic kidney disease (CKD), contrast media compatible with renal impairment is sorely needed. We present the new manganese(II) complex [Mn(PyC3A)(H2O)]- as a Gd alternative. [Mn(PyC3A)(H2O)]- is amongst the most stable Mn(II) complexes at pH 7.4 (log KML = 11.40). In the presence of 25 mol equiv. Zn at pH 6.0, 37 °C, [Mn(PyC3A)(H2O)]- is 20-fold more resistant to dissociation than [Gd(DTPA)(H2O)]2-. Relaxivity of [Mn(PyC3A)(H2O)]- in blood plasma is comparable to commercial Gd contrast agents. Biodistribution analysis confirms that [Mn(PyC3A)(H2O)]- clears via a mixed renal/ hepatobiliary pathway with >99% elimination by 24h. [Mn(PyC3A)(H2O)]- was modified to form a bifunctional chelator and 4 chelates were conjugated to a fibrin-specific peptide to give Mn-FBP. Mn-FBP binds the soluble fibrin fragment DD(E) with Kd = 110 nM. Per Mn relaxivity of Mn-FBP is 4-fold greater than [Mn(PyC3A)(H2O)]- and increases 60% in the presence of fibrin, consistent with binding. Mn-FBP provided equivalent thrombus enhancement to the state of the art Gd analog, EP-2104R, in a rat model of arterial thrombosis. Mn metabolite analysis reveals no evidence of dechelation and the probe was >99% eliminated after 24 hr. [Mn(PyC3A)(H2O)]- is a lead development candidate for an imaging probe that is compatible with renally compromised patients. PMID:26588204

  4. Gadolinium-based Compounds Induce NLRP3-dependent IL-1β Production and Peritoneal Inflammation

    PubMed Central

    Schmidt-Lauber, Christian; Bossaller, Lukas; Abujudeh, Hani H.; Vladimer, Gregory I.; Christ, Anette; Fitzgerald, Katherine A.; Latz, Eicke; Gravallese, Ellen M.; Marshak-Rothstein, Ann; Kay, Jonathan

    2015-01-01

    Objective Nephrogenic systemic fibrosis (NSF) is a progressive fibrosing disorder that may develop in patients with chronic kidney disease (CKD) after administration of gadolinium-based contrast agents (GBCAs). In the setting of impaired renal clearance of GBCAs, gadolinium (Gd) deposits in various tissues and fibrosis subsequently develops. However, the precise mechanism by which fibrosis occurs in NSF is incompletely understood. Because other profibrotic agents, such silica or asbestos, activate the NOD-like receptor protein 3 (NLRP3) inflammasome and initiate IL-1β release with the subsequent development of fibrosis, we evaluated the effects of GBCAs on inflammasome activation. Methods Bone marrow derived macrophages (BMDM) from C57BL/6, Nlrp3−/− and Asc−/− mice were incubated with three Gd-containing compounds and IL-1β activation and secretion was detected by ELISA and Western blot analysis. Inflammasome activation and regulation was investigated in IL-4- and IFNγ-polarized macrophages by ELISA, qRT-PCR and NanoString nCounter analysis. Furthermore, C57BL/6 and Nlrp3−/− mice were injected i.p. with GBCA and recruitment of inflammatory cells to the peritoneum was analyzed by FACS. Results Both free Gd and GBCAs activate the NLRP3 inflammasome and induce IL-1β secretion in vitro. Gd-DTPA also induces the recruitment of neutrophils and inflammatory monocytes to the peritoneum in vivo. Gd activated IL-4-polarized macrophages more effectively than IFNγ-polarized macrophages, which preferentially expressed genes known to downregulate inflammasome activity. Conclusion These data suggest that Gd released from GBCAs triggers a NLRP3 inflammasome-dependent inflammatory response that leads to fibrosis in an appropriate clinical setting. The preferential activation of IL-4-differentiated macrophages is consistent with the predominantly fibrotic presentation of NSF. PMID:24914072

  5. Progressive increase of T1 signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted MR images in the pediatric brain exposed to multiple doses of gadolinium contrast.

    PubMed

    Roberts, Donna R; Holden, Kenton R

    2016-03-01

    Recently, there have been reports of gadolinium accumulation in the brain and bone of adult patients with normal renal function who have undergone multiple gadolinium contrast administrations. This case report gives the first description of a pediatric patient who, following multiple contrasted MRI exams, demonstrated abnormal signal on unenhanced T1-weighted imaging involving the dentate nucleus and globus pallidus, a finding which has previously been shown to represent gadolinium deposition in adults. The patient presented here had no history of intracranial pathology which would alter the blood brain barrier or abnormal renal function. The clinical significance of gadolinium accumulation in the human body is currently unknown but is of concern, particularly in pediatric patients who have a lifetime to manifest any potential adverse consequences. Therefore, research is needed to address the clinical significance, if any, of gadolinium deposition in the developing pediatric brain. Given these current uncertainties, clinicians should continue to use prudence in selecting pediatric patients to undergo contrasted MRI and in selecting the appropriate contrast agents to use.

  6. Gadolinium oxide nanoplates with high longitudinal relaxivity for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cho, Minjung; Sethi, Richa; Ananta Narayanan, Jeyarama Subramanian; Lee, Seung Soo; Benoit, Denise N.; Taheri, Nasim; Decuzzi, Paolo; Colvin, Vicki L.

    2014-10-01

    Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values moderately reduce as the size of the Gd2O3 nanoplates increases, and are always larger for the PAA-OA coating. Cytotoxicity studies on human dermal fibroblast cells documented no significant toxicity, with 100% cell viability preserved up to 250 μM for the PAA-OA coated Gd2O3 nanoplates. Given the 10 times increase in longitudinal relaxivity over the commercially available Gd-based molecular agents and the favorable toxicity profile, the 2 nm PAA-OA coated Gd2O3 nanoplates could represent a new class of highly effective T1 MRI contrast agents.Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values

  7. The study of in vivo x-ray fluorescence (XRF) technique for gadolinium (Gd) measurements in human bone

    NASA Astrophysics Data System (ADS)

    Mostafaei, F.; Nie, L. H.

    2016-08-01

    An in vivo K x-ray fluorescence system, based on 109Cd source, for the detection of gadolinium has been investigated. Gd is of interest because of the extensive use of Gd-based contrast agents in MR imaging. A human simulating bone phantom set has been developed. The phantoms were doped with seven concentrations of Gd. Additional elements important for in vivo x-ray fluorescence, Na, Cl and Ca, were also included to create an overall elemental composition consistent with the Reference Man. A new 5 GBq 109Cd source was purchased to improve the source activity in comparison to the previous study (0.17 GBq). The previously published minimum detection limit (MDL) for Gd phantom measurements using KXRF system was 3.3 ppm. In this study the minimum detection limit for bare bone phantoms was found to reduce the MDL to 0.8, a factor of 4.1. The previous published data used only three layers of plastic as soft tissue equivalent materials and found the MDL of 4-4.8 ppm. In this study we have used the plastic with more realistic thicknesses to simulate a soft tissue at tibia. The detection limits for phantoms with Lucite as a tissue equivalent, using a new source, was determined to be 1.81 to 3.47 ppm (μg Gd per gram phantom). Our next study would be testing an in vivo K x-ray fluorescence system, based on 109Cd source on human volunteers who went through MR imaging and were injected by Gd.

  8. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    SciTech Connect

    Labarga, Luis

    2010-11-24

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R and D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  9. Gadolinium-enhanced magnetic resonance angiography in brain death

    NASA Astrophysics Data System (ADS)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  10. Dressler's syndrome demonstrated by late gadolinium enhancement cardiovascular magnetic resonance

    PubMed Central

    Steadman, Christopher D; Khoo, Jeffrey; Kovac, Jan; McCann, Gerry P

    2009-01-01

    A 49-year old patient presented late with an anterolateral ST-elevation myocardial infarction and was treated with rescue angioplasty to an occluded left anterior descending artery. Her recovery was complicated by low-grade pyrexia and raised inflammatory markers. Cardiovascular magnetic resonance 5 weeks after the acute presentation showed transmural infarction and global late gadolinium enhancement of the pericardium in keeping with Dressler's syndrome. PMID:19627595

  11. Magnons as a Bose-Einstein Condensate in Nanocrystalline Gadolinium

    SciTech Connect

    Kaul, S. N.; Mathew, S. P.

    2011-06-17

    The recent observation [S. P. Mathew et al., J. Phys. Conf. Ser. 200, 072047 (2010)] of the anomalous softening of spin-wave modes at low temperatures in nanocrystalline gadolinium is interpreted as a Bose-Einstein condensation (BEC) of magnons. A self-consistent calculation, based on the BEC picture, is shown to closely reproduce the observed temperature variations of magnetization and specific heat at constant magnetic fields.

  12. Progress in the use of gadolinium for NCT.

    PubMed

    Cerullo, N; Bufalino, D; Daquino, G

    2009-07-01

    The evaluation of possible improvement in the use of Gd in cancer therapy, in reference to gadolinium in cancer therapy (GdNCT), has been analysed. At first the problem of the gadolinium compounds toxicity was reviewed identifying the Motexafin Gadolinium as the best. Afterwards, the spectrum of IC and Auger electrons was calculated using a special method. Afterwards, this electron source has been used as input of the PENELOPE code and the energy deposit in DNA was well defined. Taking into account that the electron yield and energy distribution are related to the neutron beam spectrum and intensity, the shaping assembly architecture was optimised through computational investigations. Finally the study of GdNCT was performed from two different points of view: macrodosimetry using MCNPX, with calculation of absorbed doses both in tumour and healthy tissues, and microdosimetry using PENELOPE, with the determination of electron RBE through the energy deposit. The equivalent doses were determined combining these two kinds of data, introducing specific figures of merit to be used in treatment planning system (TPS). According to these results, the GdNCT appears to be a fairly possible tumour therapy.

  13. Magnetization of 2.6 T in gadolinium thin films

    NASA Astrophysics Data System (ADS)

    Scheunert, G.; Hendren, W. R.; Ward, C.; Bowman, R. M.

    2012-10-01

    There is renewed interest in rare-earth elements and gadolinium in particular for a range of studies in coupling physics and applications. However, it is still apparent that synthesis impacts understanding of the intrinsic magnetic properties of thin gadolinium films, particularly for thicknesses of topicality. We report studies on 50 nm thick nanogranular polycrystalline gadolinium thin films on SiO2 wafers that demonstrate single-crystal like behavior. The maximum in-plane saturation magnetization at 4 K was found to be 4πMS4 K = (2.61 ± 0.26) T with a coercivity of HC4 K = (160 ± 5) Oe. A maximum Curie point of TC = (293 ± 2) K was measured via zero-field-cooled-field-cooled magnetization measurements in close agreement with values reported in bulk single crystals. Our measurements revealed magnetic transitions at T1 = (12 ± 2) K (as deposited samples) and T2 = (22 ± 2) K (depositions on heated substrates) possibly arising from the interaction of paramagnetic face-centred cubic grains with their ferromagnetic hexagonal close-packed counterparts.

  14. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla.

    PubMed

    Kelle, Sebastian; Schlendorf, Kelly; Hirsch, Glenn A; Gerstenblith, Gary; Fleck, Eckart; Weiss, Robert G; Stuber, Matthias

    2010-10-11

    Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd) contrast administration and coronary vessel wall enhancement (LGE) detected by 3T magnetic resonance imaging (MRI) in healthy subjects and patients with coronary artery disease (CAD). Materials and Methods. Four healthy subjects (4 men, mean age 29 ± 3 years and eleven CAD patients (6 women, mean age 61 ± 10 years) were studied on a commercial 3.0 Tesla (T) whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands). T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI) was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd) (0.1 mmol/kg Gd-DTPA). Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3%) segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0%) and at time-interval 3, 29 of 39 evaluable segments (74.4%) were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30-45 minutes after administration of the contrast agent.

  15. Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys

    NASA Astrophysics Data System (ADS)

    Maltsev, Dmitry S.; Volkovich, Vladimir A.; Yamshchikov, Leonid F.; Chukin, Andrey V.

    2016-09-01

    Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys were studied. Temperature dependences of gadolinium activity in the studied alloys were determined at 573-1073 K employing the EMF method. Solubility of gadolinium in the Ga-Sn and Ga-Zn alloys was measured at 462-1073 K using IMCs sedimentation method. Activity coefficients as well as partial and excess thermodynamic functions of gadolinium in the studied alloys were calculated on the basis of the obtained experimental data.

  16. [CT contrast administration of iodine, gadolinium and ytterbium. In-vitro studies and animal experiments].

    PubMed

    Zwicker, C; Langer, M; Urich, V; Felix, R

    1993-03-01

    The absorption of the elements iodine, gadolinium and 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 190HU and 21HU respectively compared with iodine which gave 157HU and 12HU respectively. The animal experimental studies suggest that gadolinium and ytterbium are suitable contrast media for dynamic CT investigations.

  17. Combination of boron and gadolinium compounds for neutron capture therapy. An in vitro study.

    PubMed

    Matsumura, A; Zhang, T; Nakai, K; Endo, K; Kumada, H; Yamamoto, T; Yoshida, F; Sakurai, Y; Yamamoto, K; Nose, T

    2005-03-01

    In neutron capture therapy, the therapeutic effect of the boron compound is based on alpha particles produced by the B(n, alpha) reaction while with the gadolinium compound the main radiation effect is from gamma rays derived from the Gd(n, gamma) reaction. The uptake and distribution within the tumor may be different among these compounds. Thus, the combination of the boron and gadolinium compounds may be beneficial for enhancing the radiation dose to the tumor. Chinese hamster fibroblast V79 cells were used. For the neutron targeting compounds, 10B (BSH) at 0, 5, 10, and 15 ppm, and 157Gd (Gd-BOPTA) at 0, 800, 1600, 2400, 3200, and 4800 ppm, were combined. The neutron irradiation was performed with thermal neutrons for 30 min. (neutron flux: 0.84 x 10(8) n/cm2/s in free air). The combination of the boron and gadolinium compounds showed an additive effect when the gadolinium concentration was lower than 1600 ppm. This additive effect decreased as a function of gadolinium concentration at 2400 ppm and resulted in no additive effect at more than 3200 ppm of gadolinium. In conclusion, the combination of the boron and gadolinium compounds can enhance the therapeutic effect with an optimum concentration ratio. When the gadolinium concentration is too high, it may weaken the boron neutron capture reaction due to the high cross-section of gadolinium compound against neutrons.

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

    SciTech Connect

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

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer 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{sub 1}) or transverse (T{sub 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{sub 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{sub 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

  19. High longitudinal relaxivity of ultra-small gadolinium oxide prepared by microsecond laser ablation in diethylene glycol

    SciTech Connect

    Luo Ningqi; Xiao Jun; Hu Wenyong; Chen Dihu; Tian Xiumei; Yang Chuan; Li Li

    2013-04-28

    Ultra-small gadolinium oxide (Gd{sub 2}O{sub 3}) can be used as T{sub 1}-weighted Magnetic Resonance Imaging (MRI) contrast agent own to its high longitudinal relaxivity (r{sub 1}) and has attracted intensive attention in these years. In this paper, ultra-small Gd{sub 2}O{sub 3} nanoparticles of 3.8 nm in diameter have been successfully synthesized by a microsecond laser ablating a gadolinium (Gd) target in diethylene glycol (DEG). The growth inhibition effect induced by the large viscosity of DEG makes it possible to synthesize ultra-small Gd{sub 2}O{sub 3} by laser ablation in DEG. The r{sub 1} value and T{sub 1}-weighted MR images are measured by a 3.0 T MRI spectroscope. The results show these nanoparticles with a high r{sub 1} value of 9.76 s{sup -1} mM{sup -1} to be good MRI contrast agents. We propose an explanation for the high r{sub 1} value of ultra-small Gd{sub 2}O{sub 3} by considering the decreasing factor (surface to volume ratio of the nanoparticles, S/V) and the increasing factor (water hydration number of the Gd{sup 3+} on Gd{sub 2}O{sub 3} surface, q), which offer a new look into the relaxivity studies of MRI contrast agents. Our research provides a new approach to preparing ultra-small Gd{sub 2}O{sub 3} of high r{sub 1} value by laser ablation in DEG and develops the understanding of high relaxivity of ultra-small Gd{sub 2}O{sub 3} MRI contrast agents.

  20. Poly(lactic-co-glycolic acid) encapsulated gadolinium oxide nanoparticles for MRI-based cell tracking.

    PubMed

    Bennewitz, Margaret F; Williams, Simone S; Nkansah, Michael K; Shapiro, Erik M

    2013-06-01

    Superparamagnetic iron oxide particles have proven useful for cell tracking applications by monitoring cell transplantation and migration in living organisms. However, one perceived drawback is that these particles cause dark contrast in MRI, sometimes yielding confusion with other biological phenomena, which also yield dark contrast. To that end, researchers have investigated the use of gadolinium oxide (Gd2O3) based contrast agents for MRI-based cell tracking, as Gd2O3 has favorable r1 molar relaxivity. We synthesized Gd2O3 nanocrystals and encapsulated them within PLGA matrices to form approximatley to 150 nm nanoparticles. r1 was 1.9 mM(-1) sec(-1) and r2 was 8.4 mM(-1) sec(-1). Cell labeling with particles was well tolerated by cells except at very high doses. MRI of labeled cells showed that labeled cells could achieve both R1 and R2 enhancements due to the internalized particles. R2 enhancements were approximately to twice that of R1 enhancements suggesting the use of very short echo times when using Gd2O3 based contrast agents for MRI-based cell tracking.

  1. Use of Gadolinium as a Primary Criticality Control in Disposing Waste Containing Plutonium at SRS

    SciTech Connect

    Andrew, Vincent

    2005-01-04

    Use of gadolinium as a neutron poison has been proposed for disposing of several metric tons of excess plutonium at the Savannah River Site (SRS). The plutonium will first be dissolved in nitric acid in small batches. Gadolinium nitrate will then be added to the plutonium nitrate solution. The Gd-poisoned plutonium solution will be neutralized and transferred to large under-ground tanks. The pH of small batches of neutralized plutonium solution will be adjusted prior to addition of the glass frit for eventual production as glass logs. The use of gadolinium as the neutron poison would minimize the number of glass logs generated from this disposition. The primary criticality safety concerns regarding the disposal process are: (1) maintaining neutron moderation under all processing conditions since gadolinium has a very large absorption cross section for thermal neutrons, (2) characteristics of plutonium and gadolinium precipitation during the neutralization process, (3) mixing characteristics of the precipitate to ensure that plutonium would remain homogeneously mixed with gadolinium, and (4) potential separation of plutonium and gadolinium during nitric and formic acids addition. A number of experiments were conducted at the Savannah River National Laboratory to study the behavior of plutonium and gadolinium at various stages of the disposition process.

  2. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect

    Mukherjee, A. Banerjee, M. Basu, S.; Pal, M.

    2014-04-24

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  3. Dual-Energy X-Radiography With Gadolinium Filter

    NASA Technical Reports Server (NTRS)

    Rutt, Brian

    1987-01-01

    Image resolution increased, and cost reduced. Proposed dual-energy x-ray imaging system, continuous bremsstrahlung spectrum from x-ray tube filtered by foil of nonradioactive gadolinium or another rare-earth metal to form two-peaked energy spectrum. After passing through patient or object under examination, filtered radiation detected by array of energy-discriminating, photon-counting detectors. Detector outputs processed to form x-ray image for each peak and possibly enhanced image based on data taken at both peaks.

  4. Magnetoresistance of polycrystalline gadolinium with varying grain size

    SciTech Connect

    Chakravorty, Manotosh Raychaudhuri, A. K.

    2015-01-21

    In this paper, we report a study of evolution of low field magnetoresistance (MR) of Gadolinium as the grain size in the sample is changed from few microns (∼4 μm) to the nanoscopic regime (∼35 nm). The low field MR has a clear effect on varying grain size. In large grain sample (few μm), the magnetic domains are controlled by local anisotropy field determined mainly by the magnetocrystalline anisotropy. The low field MR clearly reflects the temperature dependence of the magnetocrystalline anisotropy. For decreasing gain size, the contribution of spin disorder at the grain boundary increases and enhances the local anisotropy field.

  5. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Mukherjee, A.; Banerjee, M.; Basu, S.; Pal, M.

    2014-04-01

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  6. Sensitivity of alanine dosimeters with gadolinium exposed to 6 MV photons at clinical doses.

    PubMed

    Marrale, M; Longo, A; Spanò, M; Bartolotta, A; D'Oca, M C; Brai, M

    2011-12-01

    In this study we analyzed the ESR signal of alanine dosimeters with gadolinium exposed to 6 MV linear accelerator photons. We observed that the addition of gadolinium brings about an improvement in the sensitivity to photons because of its high atomic number. The experimental data indicated that the addition of gadolinium increases the sensitivity of the alanine to 6 MV photons. This enhancement was better observed at high gadolinium concentrations for which the tissue equivalence is heavily reduced. However, information about the irradiation setup and of the radiation beam features allows one to correct for this difference. Monte Carlo simulations were carried out to obtain information on the expected effect of the addition of gadolinium on the dose absorbed by the alanine molecules inside the pellets. These results are compared with the experimental values, and the agreement is discussed.

  7. Gadolinium Thin Foils in a Plasma Panel Sensor as an Alternative to 3He

    SciTech Connect

    Varner Jr, Robert L; Beene, James R; Friedman, Dr. Peter S.

    2010-01-01

    Gadolinium has long been investigated as a detector for neutrons. It has a thermal neutron capture cross-section that is unparalleled among stable elements, because of the isotopes $^{155,157}$Gd. As a replacement for $^3$He, gadolinium has a significant defect, it produces many gamma-rays with an energy sum of 8 MeV. It also produces conversion electrons, mostly 29 keV in energy. The key to replacing $^3$He with gadolinium is using a gamma-blind electron detector to detect the conversion electrons. We suggest that coupling a layer of gadolinium to a Plasma Panel Sensor (PPS) can provide highly efficient, nearly gamma-blind detection of the conversion. The PPS is a proposed detector under development as a dense array of avalanche counters based on plasma display technology. We will present simulations of the response of prototypes of this detector and considerations of the use of gadolinium in the PPS.

  8. Reversible low-light induced photoswitching of crowned spiropyran-DO3A complexed with gadolinium(III) ions.

    PubMed

    Kruttwig, Klaus; Yankelevich, Diego R; Brueggemann, Chantal; Tu, Chuqiao; L'etoile, Noelle; Knoesen, André; Louie, Angelique Y

    2012-05-31

    Photoswitchable spiropyran has been conjugated to the crowned ring system DO3A, which improves its solubility in dipolar and polar media and stabilizes the merocyanine isomer. Adding the lanthanide ion gadolinium(III) to the macrocyclic ring system leads to a photoresponsive magnetic resonance imaging contrast agent that displays an increased spin-lattice relaxation time (T₁) upon visible light stimulation. In this work, the photoresponse of this photochromic molecule to weak light illumination using blue and green light emitting diodes was investigated, simulating the emission spectra from bioluminescent enzymes. Photon emission rate of the light emitting diodes was changed, from 1.75 × 10¹⁶ photons·s⁻¹ to 2.37 × 10¹² photons·s⁻¹. We observed a consistent visible light-induced isomerization of the merocyanine to the spiropyran form with photon fluxes as low as 2.37 × 10¹² photons·s⁻¹ resulting in a relaxivity change of the compound. This demonstrates the potential for use of the described imaging probes in low light level applications such as sensing bioluminescence enzyme activity. The isomerization behavior of gadolinium(III)-ion complexed and non-complexed spiropyran-DO3A was analyzed in water and ethanol solution in response to low light illumination and compared to the emitted photon emission rate from over-expressed Gaussia princeps luciferase.

  9. Monte Carlo Study of Radiation Dose Enhancement by Gadolinium in Megavoltage and High Dose Rate Radiotherapy

    PubMed Central

    Zhang, Daniel G.; Feygelman, Vladimir; Moros, Eduardo G.; Latifi, Kujtim; Zhang, Geoffrey G.

    2014-01-01

    MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF) and conventional flattened 6MV photon beams were used. High dose rate (HDR) brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL) would be needed. PMID:25275550

  10. Low field magnetoresistance of gadolinium nanowire

    SciTech Connect

    Chakravorty, Manotosh Raychaudhuri, A. K.

    2014-02-07

    We report low field (μ{sub 0}H < 0.2 T) magnetoresistance (MR) studies on a single Gd nanowire patterned from a nano-structured film (average grain size ∼ 35 nm) by focused ion beam. For comparison, we did similar MR measurements on a polycrystalline sample with large crystallographic grains (∼4 μm). It is observed that in the low field region where the MR is due to motion of magnetic domains, the MR in the large grained sample shows a close relation to the characteristic temperature dependent magnetocrystalline anisotropy including a sharp rise in MR at the spin reorientation transition at 235 K. In stark contrast, in the nanowire, the MR shows complete suppression of the above behaviours and it shows predominance of the grain boundary and spin disorder controlling the domain response.

  11. Synergy between surface and core entrapped metals in a mixed manganese-gadolinium nanocolloid affords safer MR imaging of sparse biomarkers.

    PubMed

    Wang, Kezheng; Pan, Dipanjan; Schmieder, Anne H; Senpan, Angana; Hourcade, Dennis E; Pham, Christine T N; Mitchell, Lynne M; Caruthers, Shelton D; Cui, Grace; Wickline, Samuel A; Shen, Baozhong; Lanza, Gregory M

    2015-04-01

    High-relaxivity T1-weighted (T1w) MR molecular imaging nanoparticles typically present high surface gadolinium payloads that can elicit significant acute complement activation (CA). The objective of this research was to develop a high T1w contrast nanoparticle with improved safety. We report the development, optimization, and characterization of a gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC; 138±10 (Dav)/nm; PDI: 0.06; zeta: -27±2 mV). High r1 particulate relaxivity with minute additions of Gd-DOTA-lipid conjugate to the MnOL nanocolloid surface achieved an unexpected paramagnetic synergism. This hybrid MnOL-Gd NC provided optimal MR TSE signal intensity at 5 nM/voxel and lower levels consistent with the level expression anticipated for sparse biomarkers, such as neovascular integrins. MnOL NC produced optimal MR TSE signal intensity at 10 nM/voxel concentrations and above. Importantly, MnOL-Gd NC avoided acute CA in vitro and in vivo while retaining minimal transmetallation risk. From the clinical editor: The authors developed a gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC) in this study. These were used as a high-relaxivity paramagnetic MR molecular imaging agent in experimental models. It was shown that MnOL-Gd NC could provide high T1w MR contrast for targeted imaging. As the level of gadolinium used was reduced, there was also reduced risk of systemic side effects from complement activation.

  12. Pediatric Brain: Repeated Exposure to Linear Gadolinium-based Contrast Material Is Associated with Increased Signal Intensity at Unenhanced T1-weighted MR Imaging.

    PubMed

    Flood, Thomas F; Stence, Nicholas V; Maloney, John A; Mirsky, David M

    2017-01-01

    Purpose To determine whether repeated exposure of the pediatric brain to a linear gadolinium-based contrast agent (GBCA) is associated with an increase in signal intensity (SI) relative to that in GBCA-naive control subjects at unenhanced T1-weighted magnetic resonance (MR) imaging. Materials and Methods This single-center, retrospective study was approved by the institutional review board and compliant with HIPAA. The authors evaluated 46 pediatric patients who had undergone at least three GBCA-enhanced MR examinations (30 patients for two-group analysis and 16 for pre- and post-GBCA exposure comparisons) and 57 age-matched GBCA-naive control subjects. The SI in the globus pallidus, thalamus, dentate nucleus, and pons was measured at unenhanced T1-weighted MR imaging. Globus pallidus-thalamus and dentate nucleus-pons SI ratios were calculated and compared between groups and relative to total cumulative gadolinium dose, age, sex, and number of and mean time between GBCA-enhanced examinations. Analysis included the Wilcoxon signed rank test, Wilcoxon rank sum test, and Spearman correlation coefficient. Results Patients who underwent multiple GBCA-enhanced examinations had increased SI ratios within the dentate nucleus (mean SI ratio ± standard error of the mean for two-group comparison: 1.007 ± 0.0058 for GBCA-naive group and 1.046 ± 0.0060 for GBCA-exposed group [P < .001]; mean SI ratio for pre- and post-GBCA comparison: 0.995 ± 0.0062 for pre-GBCA group and 1.035 ± 0.0063 for post-GBCA group [P < .001]) but not the globus pallidus (mean SI ratio for two-group comparison: 1.131 ± 0.0070 for GBCA-naive group and 1.014 ± 0.0091 for GBCA-exposed group [P = .21]; mean SI ratio for pre- and post-GBCA comparison: 1.068 ± 0.0094 for pre-GBCA group and 1.093 ± 0.0134 for post-GBCA group [P = .12]). There was a significant correlation between dentate nucleus SI and total cumulative gadolinium dose (r = 0.4; 95% confidence interval [CI]: 0.03, 0.67; P = .03), but

  13. Dielectric and magnetic properties of some gadolinium silica nanoceramics

    SciTech Connect

    Coroiu, I. Pascuta, P. Bosca, M. Culea, E.

    2013-11-13

    Some nanostructure gadolinium silica glass-ceramics were obtained undergoing a sol gel method and a heat-treatment at 1000°C about two hours. The magnetic and dielectric properties of these samples were studied. The magnetic properties were evidenced performing susceptibility measurements in the 80-300K temperature range. A Curie-Weiss behavior has acquired. The values estimated for paramagnetic Curie temperature being small and positive suggest the presence of weak ferromagnetic interactions between Gd{sup 3+} ions. The dielectric properties were evaluated from dielectric permittivity (ε{sub r}) and dielectric loss (tanδ) measurements at the frequency 1 kHz, 10 kHz and 100 kHz, in the 25-225°C temperature range and dielectric dispersion at room temperature for 79.5 kHz - 1GHz frequency area. The dielectric properties suggest that the main polarization mechanism corresponds to interfacial polarization, characteristic for polycrystalline-structured dielectrics. The polycrystalline structure of the samples is due to the polymorphous transformations of the nanostructure silica crystallites in the presence of gadolinium oxide. They were highlighted by SEM micrographs.

  14. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    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.

  15. Pressure-Induced Phase Transitions In Gadolinium Iron Borate

    NASA Astrophysics Data System (ADS)

    Kharlamova, S. A.; Struzhkin, V. V.; Sinogeikin, S. V.; Gavriliuk, A. G.; Brown, D.; Toellner, T.; Zhao, J.; Lerche, M.; Lyubutin, I. S.; Ovchinnikov, S. G.; Alp, E. E.; Sturhahn, W.

    2007-12-01

    An understanding of spin crossover (SC) dynamics is relevant to understanding of a role or participation of SC in natural systems including lower Mantle minerals, heme proteins as well as from fundamental science of view. For example, pressure-induced electronic spin transitions of Fe2+ and Fe3+ iron occur in magnesiowustite, silicate perovskite and post-perovskite which are abundant minerals in the Earth's lower mantle [1-3]. Such a SC phenomenon has recently been observed in a number of magnetic minerals FeBO3 [4, 5], BiFeO3 [6], Fe2O3 [7], and Y3Fe5O12 [8], (La, Pr)FeO3 [9, 10]. In those cases, iron ions are in the trivalent state Fe3+ and the high-spin-low-spin (HS-LS) crossover is manifested as the collapse of the local magnetic moment and as the transition of the antiferromagnet to a paramagnetic state. For example, in FeBO3 at low temperatures a spin-crossover and some magnetic transitions with two triple points were found [4, 5]. Gadolinium iron borate, GdFe3(BO3)4 is also a system with SEC and recently, we have reported on phase transitions induced by high pressures in this material [11, 12]. We studied the structural and magnetic behavior of GdFe573(BO3)4 at high pressures and temperatures using a diamond anvil cell and a Synchrotron Mossbauer Spectroscopy technique. The hyperfine parameters and results obtained from the experiments are discussed. Based on our experimental data and theoretical calculation a tentative magnetic P-T phase diagram and an equation of states of GdFe573(BO3)4 are proposed. Important features of the phase diagram are a spin crossover, insulator-semiconductor transition and possible presence of two triple points where magnetic and paramagnetic phases of the high-spin and low-spin states coexist. 1. J. Badro, J.-P. Rueff, G. Vankó, et al., Science 305, 383 (2004). 2. J. M. Jackson, W. Sturhahn, G. Shen, et al., American Mineralogist 90, 199 (2005). 3. J.Li, V.V. Struzhkin, H.-K. Mao, et al., PNAS 101, 14027 (2004). 4. I.A. Troyan

  16. Regional Convection-Enhanced Delivery of Gadolinium-labeled Albumin in the Rat Hippocampus In Vivo

    PubMed Central

    Astary, Garrett W.; Kantorovich, Svetlana; Carney, Paul R.; Mareci, Thomas H.; Sarntinoranont, Malisa

    2010-01-01

    Convection-enhanced delivery (CED) has emerged as a promising method of targeted drug-delivery for treating central nervous system (CNS) disorders, but the influence of brain structure on infusate distribution is unclear. We have utilized this approach to study extracellular transport and distribution of a contrast agent in the hippocampus, a complex structure susceptible to CNS disorders. The magnetic resonance (MR) contrast agent diethylene triamene penta-acetic acid chelated gadolinium-labeled albumin (Gd-albumin), tagged with Evans blue dye, was directly infused into the dorsal and ventral hippocampus of seven male Sprague-Dawley rats. The final distribution profile of the contrast agent, a product of CED and limited diffusion, was observed in vivo using high-resolution T1-weighted MR imaging at 11.1 Tesla. Dense cell layers, such as the granule cell layer of the dentate gyrus and the pyramidal cell layer of CA1, appeared to be barriers to transport of the tracer. Three-dimensional distribution shape and volume (Vd) differences, between the dorsal and ventral hippocampus infusions, were determined from the MR images using a semi-automatic segmentation routine (Dorsal Vd = 23.4 ± 1.8 μl, Ventral Vd = 36.4 ± 5.1 μl). Finer structural detail of the hippocampus was obtained using a combination of histological analysis and fluorescence imaging. This study demonstrates that CED has the potential to target all regions of the hippocampus and that tracer distribution is influenced by infusion site, underlying structure and circuitry, and extent of backflow. Therefore, CED, combined with high-resolution MR imaging, may be a useful strategy for delivering therapeutics for the treatment of CNS disorders affecting the hippocampus. PMID:20067808

  17. Aqueous stability of gadolinium in surface waters receiving sewage treatment plant effluent Boulder Creek, Colorado

    USGS Publications Warehouse

    Verplanck, P.L.; Taylor, H.E.; Nordstrom, D.K.; Barber, L.B.

    2005-01-01

    In many surface waters, sewage treatment plant (STP) effluent is a substantial source of both regulated and unregulated contaminants, including a suite of complex organic compounds derived from household chemicals, pharmaceutical, and industrial and medical byproducts. In addition, STP effluents in some urban areas have also been shown to have a positive gadolinium (Gd) anomaly in the rare earth element (REE) pattern, with the Gd derived from its use in medical facilities. REE concentrations are relatively easy to measure compared to many organic wastewater compounds and may provide a more widely utilized tracer of STP effluents. To evaluate whether sewage treatment plant-associated Gd is a useful tracer of treatment plant effluent, an investigation of the occurrence, fate, and transport of rare earth elements was undertaken. The rare earth element patterns of four of five STP effluents sampled display positive Gd anomalies. The one site that did not have a Gd anomaly serves a small community, population 1200, with no medical facilities. Biosolids from a large metropolitan STP are not enriched in Gd even though the effluent is, suggesting that a substantial fraction of Gd remains in the aqueous phase through routine treatment plant operation. To evaluate whether STP-derived Gd persists in the fluvial environment, a 14-km study reach downstream of an STP was sampled. Gadolinium anomalies were present at all five downstream sites, but the magnitude of the anomaly decreased. Effluent from STPs is a complex mixture of organic and inorganic constituents, and to better understand the chemical interactions and their effect on REEs, the aqueous speciation was modeled using comprehensive chemical analyses of water samples collected downstream of STP input. These calculations suggest that the REEs will likely remain dissolved because phosphate and carbonate complexes dominate over free REE ions. This study supports the application of Gd anomalies as a useful tracer of urban

  18. Gadolinium-Based Nanoparticles and Radiation Therapy for Multiple Brain Melanoma Metastases: Proof of Concept before Phase I Trial

    PubMed Central

    Kotb, Shady; Detappe, Alexandre; Lux, François; Appaix, Florence; Barbier, Emmanuel L.; Tran, Vu-Long; Plissonneau, Marie; Gehan, Hélène; Lefranc, Florence; Rodriguez-Lafrasse, Claire; Verry, Camille; Berbeco, Ross; Tillement, Olivier; Sancey, Lucie

    2016-01-01

    Nanoparticles containing high-Z elements are known to boost the efficacy of radiation therapy. Gadolinium (Gd) is particularly attractive because this element is also a positive contrast agent for MRI, which allows for the simultaneous use of imaging to guide the irradiation and to delineate the tumor. In this study, we used the Gd-based nanoparticles, AGuIX®. After intravenous injection into animals bearing B16F10 tumors, some nanoparticles remained inside the tumor cells for more than 24 hours, indicating that a single administration of nanoparticles might be sufficient for several irradiations. Combining AGuIX® with radiation therapy increases tumor cell death, and improves the life spans of animals bearing multiple brain melanoma metastases. These results provide preclinical proof-of-concept for a phase I clinical trial. PMID:26909115

  19. Induction of sister chromatid exchange in the presence of gadolinium-DTPA and its reduction by dimethyl sulfoxide

    SciTech Connect

    Yamazaki, Etsuo; Fukuda, Hozumi; Shibuya, Hitoshi; Matsubara, Sho

    1996-05-01

    The authors investigate the frequency of sister chromatid exchange (SCE) after the addition of gadolinium (Gd)-DTPA to venous blood samples. Venous blood was obtained from nonsmokers. Samples were incubated with Gd-DTPA alone or in combination with mitomycin C, cytarabine, and dimethyl sulfoxide (DMSO), and then evaluated for SCEs. The frequency of SCE increased with the concentration of Gd-DTPA and as each chemotherapeutic agent was added. Sister chromatid exchange frequencies were lower when the blood was treated with a combination of Gd-DTPA and DMSO compared with Gd-DTPA alone. The increase in frequency of SCE seen after the addition of Gd-DTPA was decreased by the addition of DMSO, indicating the production of hydroxyl radicals. The effect likely is dissociation-related. 14 refs., 6 tabs.

  20. High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

    PubMed Central

    Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

    2017-01-01

    Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. PMID:28091590

  1. Sorafenib and gadolinium co-loaded liposomes for drug delivery and MRI-guided HCC treatment.

    PubMed

    Xiao, Yanan; Liu, Yongjun; Yang, Shaomei; Zhang, Bo; Wang, Tianqi; Jiang, Dandan; Zhang, Jing; Yu, Dexin; Zhang, Na

    2016-05-01

    To improve the poor water solubility of sorafenib and to monitor its distribution and the early feedback effects on its in vivo treatment efficacy in a precise manner, sorafenib (SF) and gadolinium (Gd) co-loaded liposomes (SF/Gd-liposomes) were prepared. The simultaneous imaging and therapy efficacies of the SF/Gd-liposomes were tested. The solubility of SF in SF/Gd-liposomes was significantly increased from 0.21 μg/mL to 250 μg/mL. The imaging capability of SF/Gd-liposomes were tested by in-vitro and the in-vivo imaging ability tests and the results confirmed that SF/Gd-liposomes could be served as an effective contrast agent. The design of SF/Gd-liposomes allowed the MRI-guided in vivo visualization of the delivery and biodistribution of liposome. In the in vivo antitumor studies, SF/Gd-liposomes had better antitumor effects in H22 tumor-bearing mice than SF solution (oral or i.v. administration) (P<0.05). These findings indicated that the SF/Gd-liposomes could be used as the promising nano-carriers for the MRI-guided in vivo visualization of the delivery and HCC treatment.

  2. Phase-Sensitive Inversion Recovery for Detecting Myocardial Infarction Using Gadolinium-Delayed Hyperenhancement

    PubMed Central

    Kellman, Peter; Arai, Andrew E.; McVeigh, Elliot R.; Aletras, Anthony H.

    2007-01-01

    After administration of gadolinium, infarcted myocardium exhibits delayed hyperenhancement and can be imaged using an inversion recovery (IR) sequence. The performance of such a method when using magnitude-reconstructed images is highly sensitive to the inversion recovery time (TI) selected. Using phase-sensitive reconstruction, it is possible to use a nominal value of TI, eliminate several breath-holds otherwise needed to find the precise null time for normal myocardium, and achieve a consistent contrast. Phase-sensitive detection is used to remove the background phase while preserving the sign of the desired magnetization during IR. Experimental results are presented which demonstrate the benefits of both phase-sensitive IR image reconstruction and surface coil intensity normalization for detecting myocardial infarction (MI). The phase-sensitive reconstruction method reduces the variation in apparent infarct size that is observed in the magnitude images as TI is changed. Phase-sensitive detection also has the advantage of decreasing the sensitivity to changes in tissue T1 with increasing delay from contrast agent injection. PMID:11810682

  3. High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

    NASA Astrophysics Data System (ADS)

    Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

    2017-01-01

    Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

  4. [Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

    PubMed

    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.

  5. Gadolinium chloride elicits apoptosis in human osteosarcoma U-2 OS cells through extrinsic signaling, intrinsic pathway and endoplasmic reticulum stress.

    PubMed

    Tsai, Yuh-Feng; Huang, Ching-Wen; Chiang, Jo-Hua; Tsai, Fuu-Jen; Hsu, Yuan-Man; Lu, Chi-Cheng; Hsiao, Chen-Yu; Yang, Jai-Sing

    2016-12-01

    Gadolinium (Gd) compounds are important as magnetic resonance imaging (MRI) contrast agents, and are potential anticancer agents. However, no report has shown the effect of gadolinium chloride (GdCl3) on osteosarcoma in vitro. The present study investigated the apoptotic mechanism of GdCl3 on human osteosarcoma U-2 OS cells. Our results indicated that GdCl3 significantly reduced cell viability of U-2 OS cells in a concentration-dependent manner. GdCl3 led to apoptotic cell shrinkage and DNA fragmentation in U-2 OS cells as revealed by morphologic changes and TUNEL staining. Colorimetric assay analyses also showed that activities of caspase-3, caspase-8, caspase-9 and caspase-4 occurred in GdCl3-treated U-2 OS cells. Pretreatment of cells with pan-caspase inhibitor (Z-VAD-FMK) and specific inhibitors of caspase-3/-8/-9 significantly reduced cell death caused by GdCl3. The increase of cytoplasmic Ca2+ level, ROS production and the decrease of mitochondria membrane potential (ΔΨm) were observed by flow cytometric analysis in U-2 OS cells after GdCl3 exposure. Western blot analyses demonstrated that the levels of Fas, FasL, cytochrome c, Apaf-1, GADD153 and GRP78 were upregulated in GdCl3-treated U-2 OS cells. In conclusion, death receptor, mitochondria-dependent and endoplasmic reticulum (ER) stress pathways contribute to GdCl3-induced apoptosis in U-2 OS cells. GdCl3 might have potential to be used in treatment of osteosarcoma patients.

  6. Epiphyseal and physeal cartilage: normal gadolinium-enhanced MR imaging.

    PubMed

    Li, Xiaoming; Wang, Renfa; Li, Yonggang; Tang, Lihua; Hu, Junwu; Xu, Anhui

    2005-01-01

    To evaluate the normal appearance of epiphyseal and physeal cartilage on Gadolinium (Gd)-enhanced MR imaging. The appearance and enhancement ratios of 20 proximal and distal femoral epiphyses in 10 normal piglets were analyzed on Gd-enhanced MR images. The correlation of the MR imaging appearance with corresponding histological findings of immature epiphyses was examined. Our results showed that Gd-enhanced MRI could differentiate the differences in enhancement between physeal and epiphyseal cartilage and show vascular canals within the epiphyseal cartilage. Enhanced ratios in the physeal were greater than those in the epiphyseal cartilage (P < 0.005). It is concluded that Gd-enhanced MR imaging reveals epiphyseal vascular canals and shows difference in enhancement of physeal and epiphyseal cartilage.

  7. The structural response of gadolinium phosphate to pressure

    NASA Astrophysics Data System (ADS)

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    2016-09-01

    Accurate elastic constants for gadolinium phosphate (GdPO4) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO4 determined under hydrostatic conditions, 128.1(8) GPa (Kʹ=5.8(2)), is markedly different from that obtained with GdPO4 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 PO4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO4 structure is facilitated by bending/twisting of the Gd-O-P links that result in increased distortion in the GdO9 polyhedra.

  8. Defect induced mobility enhancement: Gadolinium oxide (100) on Si(100)

    SciTech Connect

    Sitaputra, W.; Tsu, R.

    2012-11-26

    Growth of predominantly single crystal (100)-oriented gadolinium oxide (Gd{sub 2}O{sub 3}) on a p-type Si(100) and growth of a polycrystal with a predominant Gd{sub 2}O{sub 3}(100) crystallite on a n-type Si(100) was performed using molecular beam epitaxy. Despite a poorer crystal structure than Gd{sub 2}O{sub 3}(110), an enhancement in carrier mobility can be found only from the Gd{sub 2}O{sub 3}(100)/n-type Si(100) interface. The mobility of 1715-1780 cm{sup 2}/V {center_dot} s was observed at room temperature, for carrier concentration >10{sup 20} cm{sup -3}. This accumulation of the electrons and the mobility enhancement may arise from the two-dimensional confinement due to charge transfer across the interface similar to transfer doping.

  9. The structural response of gadolinium phosphate to pressure

    DOE PAGES

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; ...

    2016-06-16

    In this study, accurate elastic constants for gadolinium phosphate (GdPO4) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO4 determined under hydrostatic conditions, 128.1(8) GPa (K'=5.8(2)), is markedly different from that obtained with GdPO4 under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. Finally, high pressure Raman and diffraction analysis indicate that the PO4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO4 structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO9more » polyhedra.« less

  10. The structural response of gadolinium phosphate to pressure

    SciTech Connect

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    2016-06-16

    In this study, accurate elastic constants for gadolinium phosphate (GdPO4) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO4 determined under hydrostatic conditions, 128.1(8) GPa (K'=5.8(2)), is markedly different from that obtained with GdPO4 under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. Finally, high pressure Raman and diffraction analysis indicate that the PO4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO4 structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO9 polyhedra.

  11. Fabrication and Characterization of Gadolinium Phosphate Neutron Absorber

    SciTech Connect

    Lessing, Paul Alan; Erickson, Arnold Wendell

    2003-12-01

    Hydrated gadolinium phosphate (GdPO4·1H2O) was synthesized by reacting high purity dissolved salts (gadolinium nitrates or chlorides) with phosphoric acid. The hydrated powders were shown to be extremely insoluble in water with a Ksp measured to be between 2.07 E-14 and 4.76 E-13. Calcination to between 800 and 1000 °C resulted in the formation of GdPO4 in a monazite (monoclinic) crystal structure. This was correlated with the first exothermic differential thermal analysis (DTA) peak (864.9–883.4 °C). The DTA also showed small peaks in the 1200–1250 °C range, that could be associated with a change from the monazite (monoclinic) crystal structure to the xenotime (tetragonal) crystal structure. However, calcination of a sample to 1400 °C, followed by relatively rapid cooling and XRD, showed the structure was still monazite (monoclinic). DTA results showed a melting point at 1899–1920 °C (endothermic peak). It was therefore concluded that the melting point probably was the melting of the monazite (monoclinic) phase, but may have been xenotime if a phase change at 1200–1250 °C was reversible and very rapid. The higher part of the melting range was achieved with material derived using the slightly higher purity nitrate salt. The results show that GdPO4 is an excellent candidate for a chemically stable, water-insoluble neutron absorber for inclusion in spent nuclear fuel canisters.

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

    PubMed

    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.

  13. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  14. Theoretical study of structure and stability of small gadolinium carboxylate complexes in liquid scintillator solvents.

    PubMed

    Huang, Pin-Wen

    2014-09-01

    The structural properties of three small gadolinium carboxylate complexes in three liquid scintillator solvents (pseudocumene, linear alkylbenzene, and phenyl xylylethane) were theoretically investigated using density functional theory (B3LYP/LC-RECP) and polarizable continuum model (PCM). The average interaction energy between gadolinium atom and carboxylate ligand (E(int)) and the energy difference of the highest singly occupied molecular orbital and lowest unoccupied molecular orbital (Δ(SL)) were calculated to evaluate and compare the relative stability of these complexes in solvents. The calculation results show that the larger (with a longer alkyl chain) gadolinium carboxylate complex has greater stability than the smaller one, while these gadolinium carboxylates in linear alkylbenzene were found to have greater stability than those in the other two solvents.

  15. Density of Gadolinium Nitrate Solutions for the High Flux Isotope Reactor

    SciTech Connect

    Taylor, Paul Allen; Lee, Denise L

    2009-05-01

    In late 1992, the High Flux Isotope Reactor (HFIR) was planning to switch the solution contained in the poison injection tank from cadmium nitrate to gadolinium nitrate. The poison injection system is an emergency system used to shut down the reactor by adding a neutron poison to the cooling water. This system must be able to supply a minimum of 69 pounds of gadolinium to the reactor coolant system in order to guarantee that the reactor would become subcritical. A graph of the density of gadolinium nitrate solutions over a concentration range of 5 to 30 wt% and a temperature range of 15 to 40{sup o}C was prepared. Routine density measurements of the solution in the poison injection tank are made by HFIR personnel, and an adaptation of the original graph is used to determine the gadolinium nitrate concentration. In late 2008, HFIR personnel decided that the heat tracing that was present on the piping for the poison injection system could be removed without any danger of freezing the solution; however, the gadolinium nitrate solution might get as cold as 5{sup o}C. This was outside the range of the current density-concentration correlation, so the range needed to be expanded. This report supplies a new density-concentration correlation that covers the extended temperature range. The correlation is given in new units, which greatly simplifies the calculation that is required to determine the pounds of gadolinium in the tank solution. The procedure for calculating the amount of gadolinium in the HFIR poison injection system is as follows: (1) Calculate the usable volume in the system; (2) Measure the density of the solution; (3) Calculate the gadolinium concentration using the following equation: Gd(lb/ft{sup 3}) = measured density (g/mL) x 34.681 - 34.785; (4) Calculate the amount of gadolinium in the system using the following equation: Amount of Gd(lb) = Gd concentration (lb/ft{sup 3}) x usable volume (ft{sup 3}). The equation in step 3 is exact for a temperature of

  16. Gadolinium Use in Spine Pain Management Procedures for Patients with Contrast Allergies: Results in 527 Procedures

    SciTech Connect

    Safriel, Yair Ang, Roberto; Ali, Muhammed

    2008-03-15

    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.

  17. Three-dimensional gadolinium-enhanced magnetic resonance angiography used as a "one-stop shop'' imaging procedure for venous thromboembolism: a pilot study.

    PubMed

    Obernosterer, Andrea; Aschauer, Manuela; Portugaller, Horst; Köppel, Herwig; Lipp, Rainer W

    2005-01-01

    Pulmonary embolism and deep venous thrombosis are individual manifestations of a single entity, venous thromboembolic disease. This study aimed to assess the feasibility of 3-dimensional gadolinium-enhanced magnetic resonance angiography used as an "one-stop shop'' imaging procedure visualizing both the pulmonary arteries and the deep lower venous system within a single investigation. The inclusion criterion was a proven or excluded venous thromboembolism. Diagnosis was based on an imaging work-up for pulmonary embolism including either perfusion lung scan or contrast-enhanced spiral computed tomography, or both, and an imaging work-up for deep venous thrombosis including either venous color-coded duplex sonography or ascending phlebography, or both. A gadolinium-enhanced "one-stop shop'' magnetic resonance angiography was performed within 24 hours of completed diagnostic imaging work-up for pulmonary embolism and deep venous thrombosis in 20 patients. Results of pulmonary magnetic resonance angiography were concordant with perfusion lung scan and/or computed tomography in 90% of patients. Magnetic resonance angiography results of the deep lower venous system were concordant with venous duplex sonography and/or phlebography in 75% of patients and seemed to be more precise in 25% of patients. The "one-stop shop'' imaging procedure using gadolinium-enhanced magnetic resonance angiography was feasible and proved to offer a reliable and rapid diagnostic approach in thromboembolic disease, sparing patients' exposure to ionizing radiation and iodinated contrast media.

  18. Stabilized porous liposomes with encapsulated Gd-labeled dextran as highly efficient MRI contrast agents

    PubMed Central

    Zaki, Ajlan Al; Jones, Ian W.; Hall, Henry K.; Aspinwall, Craig A; Tsourkas, Andrew

    2014-01-01

    A highly efficient contrast agent for magnetic resonance imaging was developed by encapsulating gadolinium within a stabilized porous liposome. The highly porous membrane leads to a high relaxivity of the encapsulated Gd. The stability of the liposome was improved by forming a polymer network within the bilayer membrane. PMID:24457826

  19. Structure – relaxivity relationships among targeted MR contrast agents

    PubMed Central

    Zhang, Zhaoda

    2012-01-01

    Paramagnetic gadolinium(III) complexes are widely used to increase contrast in magnetic resonance (MR) images. Contrast enhancement depends on the concentration of the gadolinium complex and on its relaxivity, an inherent property of the complex. Increased relaxivity results in greater image contrast or the ability to detect the contrast agent at a lower concentration. Increasing relaxivity enables imaging of abundant molecular targets. Relaxivity depends on the structure of the complex, kinetics of inner-sphere and second sphere water exchange, and on the rotational dynamics of the molecule. The latter, and in some cases the former, properties of the complex change when it is bound to its target. All of these properties can be rationally tuned to enhance relaxivitry. In this Microreview we summarize our efforts in understanding and optimizing the relaxivity of contrast agents targeted to serum albumin and to fibrin. PMID:22745568

  20. Immobilized contrast-enhanced MRI: Gadolinium-based long-term MR contrast enhancement of the vein graft vessel wall.

    PubMed

    Mitsouras, Dimitris; Vemula, Praveen Kumar; Yu, Peng; Tao, Ming; Nguyen, Binh T; Campagna, Christina M; Karp, Jeffrey M; Mulkern, Robert V; Ozaki, C Keith; Rybicki, Frank J

    2011-01-01

    An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance postsurgical tissue differentiation using MRI. For small-vessel (e.g., vein graft) MRI, the direct benefit of such permanent "labeling" of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast-to-noise ratio, or a combination thereof. We demonstrate, for the first time, stable long-term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified diethylenetriaminepentaacetic acid gadolinium(3+) dihydrogen complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3 T, and its long-term stability is demonstrated during a 4-month incubation period.

  1. Intravascular contrast agents suitable for magnetic resonance imaging. [Dogs

    SciTech Connect

    Runge, V.M.; Clanton, J.A.; Herzer, W.A.; Gibbs, S.J.; Price, A.C.; Partain, C.L.; James, A.E. Jr.

    1984-10-01

    Two paramagnetic chelates, chromium EDTA and gadolinium DTPA, were evaluated as potential intravenous contrast agents for magnetic resonance imaging. After evaluating both agents in vitro, in vivo studies were conducted in dogs to document changes in renal appearance produced by contrast injection. Acute splenic and renal infarction were diagnosed with contrast-enhanced MR and confirmed by gamma camera imaging following administration of Tc-99m-labeled DMSA and sulfur colloid. The authors conclude that intravenous paramagnetic contrast agents presently offer the best mechanism for assessment of tissue function and changes in perfusion with MR.

  2. Stimuli-responsive poly(N-isopropyl acrylamide)-co-tyrosine@gadolinium: Iron oxide nanoparticle-based nanotheranostic for cancer diagnosis and treatment.

    PubMed

    Roy, Ekta; Patra, Santanu; Madhuri, Rashmi; Sharma, Prashant K

    2016-06-01

    In this paper, we have prepared a stimuli-responsive polymer modified gadolinium doped iron oxide nanoparticle (poly@Gd-MNPs) as cancer theranostic agent. The responsive polymer is composed of the poly(N-isopropyl acrylamide)-co-tyrosine unit, which shows excellent loading for the anti-cancer drug (methotrexate) and stimuli dependent release (change in pH and temperature). The in vitro experiment revealed that the poly@Gd-MNPs exhibited T1-weighted MRI capability (r1=11.314mM(-1)s(-1)) with good in-vitro hyperthermia response. The prepared poly@Gd-MNPs has generated quick heating (45°C in 2min) upon exposure to an alternating magnetic field and able to travel a distance of 35cm in 1min in the presence of an external magnet. The poly@Gd-MNPs shows 86% of drug loading capacity with 70% drug release in first 2h. The cytotoxic assay (MTT) demonstrated that the nanoparticle did not affect the viability of normal human fibroblast and efficiently kill the MCF7 cancer cells in the presence of an external magnetic field. To explore the uptake of poly@Gd-MNPs in the cells, bright field cell imaging study was also performed. This study provides a valuable approach for the design of highly sensitive polymer modified gadolinium doped iron oxide-based T1 contrast agents for cancer theranostics.

  3. Monte Carlo calculations of thermal neutron capture in gadolinium: a comparison of GEANT4 and MCNP with measurements.

    PubMed

    Enger, Shirin A; Munck af Rosenschöld, Per; Rezaei, Arash; Lundqvist, Hans

    2006-02-01

    GEANT4 is a Monte Carlo code originally implemented for high-energy physics applications and is well known for particle transport at high energies. The capacity of GEANT4 to simulate neutron transport in the thermal energy region is not equally well known. The aim of this article is to compare MCNP, a code commonly used in low energy neutron transport calculations and GEANT4 with experimental results and select the suitable code for gadolinium neutron capture applications. To account for the thermal neutron scattering from chemically bound atoms [S(alpha,beta)] in biological materials a comparison of thermal neutron fluence in tissue-like poly(methylmethacrylate) phantom is made with MCNP4B, GEANT4 6.0 patch1, and measurements from the neutron capture therapy (NCT) facility at the Studsvik, Sweden. The fluence measurements agreed with MCNP calculated results considering S(alpha,beta). The location of the thermal neutron peak calculated with MCNP without S(alpha,beta) and GEANT4 is shifted by about 0.5 cm towards a shallower depth and is 25%-30% lower in amplitude. Dose distribution from the gadolinium neutron capture reaction is then simulated by MCNP and compared with measured data. The simulations made by MCNP agree well with experimental results. As long as thermal neutron scattering from chemically bound atoms are not included in GEANT4 it is not suitable for NCT applications.

  4. Chemical and mass spectrographic analysis of nuclear-grade gadolinium oxide (Gd/sub 2/O/sub 3/) powder

    SciTech Connect

    Not Available

    1981-01-01

    Analytical procedures to determine compliance of gadolinium oxide powders with specifications are presented. The following methods are described in detail: carbon by direct combustion - thermal conductivity method; total chlorine and fluorine by pyrohydrolysis ion-selective electrode method; loss of weight on ignition; sulfur by combustion - iodometric titration method; impurity elements by a spark-source mass spectrographic method; and gadolinium content in gadolinium oxide by impurity correction method. (JMT)

  5. MO-FG-BRA-07: Theranostic Gadolinium-Based AGuIX Nanoparticles for MRI-Guided Radiation Therapy

    SciTech Connect

    Detappe, A; Rottmann, J; Kunjachan, S; Berbeco, R; Tillement, O

    2015-06-15

    Purpose: AGuIX are gadolinium-based nanoparticles, initially developed for MRI, that have a potential role in radiation therapy as a radiosensitizer. Our goal is to demonstrate that these nanoparticles can both be used as an MRI contrast agent, as well as to obtain local dose enhancement in a pancreatic tumor when delivered in combination with an external beam irradiation. Methods: We performed in vitro cell uptake and radiosensitization studies of a pancreatic cancer cell line in a low energy (220kVp) beam, a standard clinical 6MV beam (STD) and a flattening filter free clinical 6MV beam (FFF). After injection of 40mM of nanoparticles, a biodistribution study was performed in vivo on mice with subcutaneous xenograft pancreatic tumors. In vivo radiation therapy studies were performed at the time point of maximum tumor uptake. Results: The concentration of AGuIX nanoparticles in Panc-1 pancreatic cancer cells, determined in vitro by MRI and ICPMS, peaks after 30 minutes with 0.3% of the initial concentration (5mg/g). Clonogenic assays show a significant effect (p<0.05) when the AGuIX are coupled with MV photon irradiation (DEF20%=1.31). Similar AGuIX tumor uptake is found in vivo by both MRI and ICPMS 30 minutes after intravenous injection. For long term survival studies, the choice of the radiation dose is determined with 5 control groups (3mice/group) irradiated with 0, 5, 10, 15, and 20Gy. Afterwards, 4 groups (8mice/group) are used to evaluate the effect of the nanoparticles. A Logrank test is performed as a statistical test to evaluate the effect of the nanoparticles. Conclusion: The combination of the MRI contrast and radiosensitization properties of gadolinium nanoparticles reveals a strong potential for usage with MRI-guided radiation therapy.

  6. X-Ray Fluorescence Analysis of Yttrium-Iron-Gadolinium Solutions Used to Prepare Spray Dried Powders.

    DTIC Science & Technology

    IRON, * GADOLINIUM , *X RAY SPECTROSCOPY, *YTTRIUM, COMPUTER PROGRAMS, SOLUTIONS(MIXTURES), QUALITY CONTROL, NITRIC ACID, RARE EARTH ELEMENTS, CHEMICAL ANALYSIS, FERRITES , PHASE SHIFT CIRCUITS, YTTRIUM IRON GARNET.

  7. Synthesis, Characterization, and Thermal Kinetics of Mixed Gadolinium: Calcium Heptamolybdate System

    PubMed Central

    Koul, R. K.; Suri, Shivani; Singh, Vishal; Bamzai, K. K.

    2014-01-01

    Synthesis of mixed gadolinium calcium heptamolybdate (GdCaHM) system in silica gel medium using single gel single tube technique has been successfully achieved. The grown crystal exhibits various morphologies, which includes spherulites, multifaceted, and square platelets. The nature of the grown material was established by X-ray diffraction (XRD) studies. Fourier transform infrared spectroscopy (FTIR) study signifies the presence of heptamolybdate (Mo7O24) and water symmetry structure, whereas energy dispersive X-ray analysis (EDAX) establishes the stoichiometric of the grown crystal as GdCaMo7O24·8H2O. The thermal behaviour was studied using the thermoanalytical techniques, which include thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Results obtained on the application of TG based models, namely, Horowitz-Metzger, Coats-Redfern, and Piloyan-Novikova, suggest the contracting cylindrical model as the relevant model for the thermal decomposition of the material. The kinetic parameters, namely, the order of reaction (n), activation energy (Ea), frequency factor (Z), and entropy (ΔS∗), were also calculated using these three models. PMID:27350973

  8. Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

    SciTech Connect

    Rahman, Md. T. Ramana, C. V.

    2014-10-28

    Gadolinium (Gd) substituted cobalt ferrites (CoFe{sub 2−x}Gd{sub x}O{sub 4}, referred to CFGO) with variable Gd content (x = 0.0–0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectroscopy analysis was performed under a wide range of frequency (f = 20 Hz–1 MHz) and temperature (T = 303–573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe{sub 2}O{sub 4} due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and capacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics.

  9. Late Gadolinium Enhancement in Patients with Nonischemic Dilated Cardiomyopathy.

    PubMed

    Memon, Sarfaraz; Ganga, Harsha V; Kluger, Jeffrey

    2016-07-01

    One-third of all patients with heart failure have nonischemic dilated cardiomyopathy (NIDM). Five-year mortality from NIDM is as high as 20% with sudden cardiac death (SCD) as the cause in 30% of the deaths. Currently, the left ventricular ejection fraction (LVEF) is used as the main criteria to risk stratify patients requiring an implantable cardioverter defibrillator (ICD) to prevent SCD. However, LVEF does not necessarily reflect myocardial propensity for electrical instability leading to ventricular tachycardia (VT) or ventricular fibrillation (VF). Due to the differential risk in various subgroups of patients for arrhythmic death, it is important to identify appropriate patients for ICD implantation so that we can optimize healthcare resources and avoid the complications of ICDs in individuals who are unlikely to benefit. We performed a systematic search and review of clinical trials of NIDM and the use of ICDs and cardiac magnetic resonance imaging with late gadolinium enhancement (LGE) for risk stratification. LGE identifies patients with NIDM who are at high risk for SCD and enables optimized patient selection for ICD placement, while the absence of LGE may reduce the need for ICD implantation in patients with NIDM who are at low risk for future VF/VT or SCD.

  10. Electronic transport in gadolinium atomic-size contacts

    NASA Astrophysics Data System (ADS)

    Olivera, B.; Salgado, C.; Lado, J. L.; Karimi, A.; Henkel, V.; Scheer, E.; Fernández-Rossier, J.; Palacios, J. J.; Untiedt, C.

    2017-02-01

    We report on the fabrication, transport measurements, and density functional theory (DFT) calculations of atomic-size contacts made of gadolinium (Gd). Gd is known to have local moments mainly associated with f electrons. These coexist with itinerant s and d bands that account for its metallic character. Here we explore whether and how the local moments influence electronic transport properties at the atomic scale. Using both scanning tunneling microscope and lithographic mechanically controllable break junction techniques under cryogenic conditions, we study the conductance of Gd when only few atoms form the junction between bulk electrodes made of the very same material. Thousands of measurements show that Gd has an average lowest conductance, attributed to single-atom contact, below 2/e2 h . Our DFT calculations for monostrand chains anticipate that the f bands are fully spin polarized and insulating and that the conduction may be dominated by s , p , and d bands. We also analyze the electronic transport for model nanocontacts using the nonequilibrium Green's function formalism in combination with DFT. We obtain an overall good agreement with the experimental results for zero bias and show that the contribution to the electronic transport from the f channels is negligible and that from the d channels is marginal.

  11. Activatable molecular MRI nanoprobe for tumor cell imaging based on gadolinium oxide and iron oxide nanoparticle.

    PubMed

    Li, Jingjing; Wang, Shan; Wu, Chen; Dai, Yue; Hou, Pingfu; Han, Cuiping; Xu, Kai

    2016-12-15

    Activatable molecular MRI nanoprobe for intracellular GSH sensing was designed. As an alternative to "always on" nanoprobe, activatable imaging nanoprobes which are designed to amplify or boost imaging signals only in response to the targets have attracted more and more attention. In this paper, we designed a novel activatable molecular magnetic resonance imaging (MRI) nanoprobe for tumor cell recognization based on a MRI signal variation induced by the distance change between T1 and T2 contrast agents (CAs) in the presence of glutathione (GSH). To achieve this aim, carboxyl group functionalized iron oxide nanoparticles (Fe3O4 NPs) and polyethylene glycol-coated gadolinium oxide (PEG-Gd2O3) NPs as T2 and T1 MRI CA were connected by cystamine which contains a disulfide linkage. Transmission electron microscopic (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FT-IR), mass spectra and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) were introduced for their characterizations. The formation of Fe3O4-cystamine-Gd2O3 (Fe3O4-SS-Gd2O3) nanocomplex resulted in a quenched T1 signal due to the near proximity of PEG-Gd2O3 NPs to Fe3O4 NPs and a "light-up" T1 signal with the cleavage of disulfide bond in the presence of GSH. These results provide not only an easy way to realize MRI of tumor cells based on the overexpressed intracellular GSH level, but also a new insight for the design of activatable MRI nanoprobe.

  12. Synchrotron X-ray Analyses Demonstrate Phosphate-Bound Gadolinium in Skin in Nephrogenic Systemic Fibrosis

    PubMed Central

    George, Simon J.; Webb, Samuel M.; Abraham, Jerrold L.; Cramer, Stephen P.

    2010-01-01

    Background Nephrogenic systemic fibrosis (NSF) is an incurable, debilitating disease found exclusively in patients with decreased kidney function and comprises a fibrosing disorder of the skin and systemic tissues. The disease is associated with exposure to Gadolinium based contrast agents (GBCA) used in magnetic resonance imaging (MRI). Tissue samples from many NSF patients contain micron-sized insoluble Gd-containing deposits. However, the precise composition and chemical nature of these particles is unclear. Objectives To clarify the precise chemical structure of the Gd-containing deposits in NSF tissues. Methods Autopsy skin tissues from a NSF patient are examined in situ using synchrotron x-ray fluorescence (SXRF) microscopy and extended absorption fine structure (EXAFS) spectroscopy and in correlation with light microscopy and the results of SEM/EDS analyses. Results The insoluble Gd deposits are shown to contain Gd no longer coordinated by GBCA chelator molecules but rather in a sodium calcium phosphate material. SXRF microscopy shows a clear correlation between Gd, Ca and P. EXAFS spectroscopy shows a very different spectrum from the GBCAs, with Gd-P distances at 3.11 Å and 3.72 Å as well as Gd-Gd distances at an average of 4.05 Å, consistent with a GdPO4 structure. Conclusions This is the first direct evidence for the chemical release of Gd from GBCA in human tissue. This supports the physical-chemical, clinical, and epidemiological data indicating a link between stability and dose of GBCA to the development of NSF. PMID:20560953

  13. Gadolinium-uptake by aquatic and terrestrial organisms-distribution determined by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Lingott, Jana; Lindner, Uwe; Telgmann, Lena; Esteban-Fernández, Diego; Jakubowski, Norbert; Panne, Ulrich

    2016-02-01

    Gadolinium (Gd) based contrast agents (CA) are used to enhance magnetic resonance imaging. As a consequence of excretion by patients and insufficient elimination in wastewater treatment plants they are detected in high concentrations in surface water. At present, little is known about the uptake of these species by living organisms in aquatic systems. Therefore the uptake of gadolinium containing chelates by plants and animals grown in exposed water or on soil irrigated with exposed water was investigated. For this purpose two types of plants were treated with two different contrast agents. The uptake of the Gd contrast agents was studied by monitoring the elemental distribution with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This technique allows the multi-elemental analysis of solid samples with high resolution and little sample preparation. The analysis of L. minor showed that the uptake of Gd correlated with the concentration of gadodiamide in the water. The higher the concentration in the exposed water, the larger the Gd signal in the LA-ICP-MS acquired image. Exposure time experiments showed saturation within one day. The L. minor had contact with the CAs through roots and fronds, whereas the L. sativum only showed uptake through the roots. These results show that an external absorption of the CA through the leaves of L. sativum was impossible. All the analyzed parts of the plant showed Gd signal from the CA; the highest being at the main vein of the leaf. It is shown that the CAs can be taken up from plants. Furthermore, the uptake and distribution of Gd in Daphnia magna were shown. The exposure via cultivation medium is followed by Gd signals on the skin and in the area of the intestine, while the uptake via exposed nutrition algae causes the significantly highest Gd intensities in the area of the intestine. Because there are hints of negative effects for human organism these findings are important as they show that Gd based

  14. CHARACTERIZATION OF AN ADVANCED GADOLINIUM NEUTRON ABSORBER ALLOY BY MEANS OF NEUTRON TRANSMISSION

    SciTech Connect

    Gregg W. Wachs

    2007-09-01

    Neutron transmission experiments were performed on samples of an advanced nickel-chromium-molybdenum-gadolinium (Ni-Cr-Mo-Gd) neutron absorber alloy. The primary purpose of the experiments was to demonstrate the thermal neutron absorbing capability of the alloy at specific gadolinium dopant levels. The new alloy is to be deployed for criticality control of highly enriched DOE SNF. For the transmission experiments, alloy test samples were fabricated with 0.0, 1.58 and 2.1 wt% natural gadolinium dispersed in a Ni-Cr-Mo base alloy. The transmission experiments were successfully carried out at the Los Alamos Neutron Science Center (LANSCE). Measured data from the neutron transmission experiments were compared to calculated results derived from a simple exponential transmission formula using only radiative capture cross sections. Excellent agreement between the measured and calculated results demonstrated the expected strong thermal absorption capability of the gadolinium poison and in addition, verified the measured elemental composition of the alloy test samples. The good agreement also indirectly confirmed that the gadolinium was dispersed fairly uniformly in the alloy and the ENDF VII radiative capture cross section data were accurate.

  15. Compensated gadolinium-loaded plastic scintillators for thermal neutron detection (and counting)

    SciTech Connect

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Hamel, Matthieu; Sguerra, Fabien; Dehe-Pittance, Chrystele; Normand, Stephane; Mechin, Laurence

    2015-07-01

    Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon part of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of a neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes. (authors)

  16. Gadolinium-Loaded Poly(N-vinylcaprolactam) Nanogels: Synthesis, Characterization, and Application for Enhanced Tumor MR Imaging.

    PubMed

    Sun, Wenjie; Thies, Sabrina; Zhang, Jiulong; Peng, Chen; Tang, Guangyu; Shen, Mingwu; Pich, Andrij; Shi, Xiangyang

    2017-02-01

    We report the synthesis of poly(N-vinylcaprolactam) nanogels (PVCL NGs) loaded with gadolinium (Gd) for tumor MR imaging applications. The PVCL NGs were synthesized via precipitation polymerization using the monomer N-vinylcaprolactam (VCL), the comonomer acrylic acid (AAc), and the degradable cross-linker 3,9-divinyl-2,4,8,10-tetraoxaspiro-[5,5]-undecane (VOU) in aqueous solution, followed by covalently binding with 2,2',2″-(10-(4-((2-aminoethyl)amino)-1-carboxy-4-oxobutyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl) triacetic acid (NH2-DOTA-GA)/Gd complexes. We show that the formed Gd-loaded PVCL NGs (PVCL-Gd NGs) having a size of 180.67 ± 11.04 nm are water dispersible, colloidally stable, uniform in size distribution, and noncytotoxic in a range of the studied concentrations. The PVCL-Gd NGs also display a r1 relaxivity (6.38-7.10 mM(-1) s(-1)), which is much higher than the clinically used Gd chelates. These properties afforded the use of the PVCL-Gd NGs as an effective positive contrast agent for enhanced MR imaging of cancer cells in vitro as well as a subcutaneous tumor model in vivo. Our study suggests that the developed PVCL-Gd NGs could be applied as a promising contrast agent for T1-weighted MR imaging of diverse biosystems.

  17. Acute Respiratory Distress Syndrome after the Use of Gadolinium Contrast Media.

    PubMed

    Park, Jihye; Byun, Il Hwan; Park, Kyung Hee; Lee, Jae-Hyun; Nam, Eun Ji; Park, Jung-Won

    2015-07-01

    Acute respiratory distress syndrome (ARDS) is a medical emergency that threatens life. To this day, ARDS is very rarely reported by iodine contrast media, and there is no reported case of ARDS induced by gadolinium contrast media. Here, we present a case with ARDS after the use of gadobutrol (Gadovist) as a magnetic resonance imaging (MRI) contrast medium. A 26 years old female without any medical history, including allergic diseases and without current use of drugs, visited the emergency room for abdominal pain. Her abdominopelvic computed tomography with iodine contrast media showed a right ovarian cyst and possible infective colitis. Eighty-three hours later, she underwent pelvis MRI after injection of 7.5 mL (0.1 mL/kg body weight) of gadobutrol (Gadovist) to evaluate the ovarian cyst. She soon presented respiratory difficulty, edema of the lips, nausea, and vomiting, and we could hear wheezing upon auscultation. She was treated with dexamethasone, epinephrine, and norepinephrine. Her chest X-ray showed bilateral central bat-wing consolidative appearance. Managed with mechanical ventilation, she was extubated 3 days later and discharged without complications.

  18. Hydroxypyridonate chelating agents

    DOEpatents

    Raymond, Kenneth N.; Scarrow, Robert C.; White, David L.

    1987-01-01

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  19. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  20. Magnetization and coercivity of nanocrystalline gadolinium iron garnet

    NASA Astrophysics Data System (ADS)

    Nguyet, Dao Thi Thuy; Duong, Nguyen Phuc; Satoh, Takuya; Anh, Luong Ngoc; Hien, Than Duc

    2013-04-01

    Gadolinium iron garnet (GdIG) nanoparticles with mean particle size of about 37 nm have been synthesized by citrate precursor gel formation followed by annealing at 800 °C for 2 hours. Magnetic behavior of clustered GdIG nanoparticles was studied in temperature range from 5 K to above Curie temperature. The sample shows a magnetization compensation temperature Tcomp˜286.5 K and a Curie temperature TC˜560 K. In comparison with the bulk saturation magnetization, the sample exhibits lower spontaneous magnetization in the temperature region from 5 K to Tcomp whereas higher spontaneous magnetization is observed at higher temperatures up to near the Curie point. The magnetization curves show a differential susceptibility in high fields which increases sharply below 50 K. At very low temperatures, irreversibility was observed in the magnetization loops, enduring in the fields up to ˜12.5 kOe. The spontaneous magnetization, high-field susceptibility and low-temperature irreversible effect were discussed based on a model for the interacting particles consisting of ferrimagnetically aligned core spins and disordered spins in surface layer which become frozen at low temperatures. We proposed a mechanism for the enhancement of the spontaneous magnetization above Tcomp in which the Gd and Fe spins in the surface layer are largely decoupled at high temperatures and the surface Fe spins realign to the magnetic moment of the core. The magnetic coercivity Hc at low temperatures is governed by the effective anisotropy whereas in the vicinity of the compensation point a peak in the coercive force shows up as a result of the so-called paraprocess with the maximum value of 1.2 kOe at Tcomp and by further increasing temperature the coercivity decreases and eventually vanishes at about 500 K. The interparticle interactions were found to play an important role in the hysteresis behavior of the sample.

  1. The structural response of gadolinium phosphate to pressure

    SciTech Connect

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    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).

  2. Animal Capture Agents

    DTIC Science & Technology

    1990-01-01

    agents and delivery systems reviewed . Questionnaires were sent to 137 Air Force bases to obtain information about the chemical agents and delivery systems...used by animal control personnel. A literature review included chemical agents, delivery methods, toxicity information and emergency procedures from...34-like agent. Users should familiarize themselves with catatonia in general and particularly that its successful use as an immobilizer doesn’t necessarily

  3. Modeling gadolinium-bearing fuel in Ringhals PWRs using CASMO/SIMULATE

    SciTech Connect

    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.

  4. Measurement of gamma-ray production from thermal neutron capture on gadolinium for neutrino experiments

    NASA Astrophysics Data System (ADS)

    Yano, Takatomi

    2017-02-01

    Recently, several scientific applications of gadolinium are found in neutrino physics experiments. Gadolinium-157 is the nucleus, which has the largest thermal neutron capture cross-section among all stable nuclei. Gadolinium-155 also has the large cross-section. These neutron capture reactions provide the gamma-ray cascade with the total energy of about 8 MeV. This reaction is applied for several neutrino experiments, e.g. reactor neutrino experiments and Gd doped large water Cherenkov detector experiments, to recognize inverse-beta-decay reaction. A good Gd(n,γ) simulation model is needed to evaluate the detection efficiency of the neutron capture reaction, i.e. the efficiency of IBD detection. In this presentation, we will report the development and study status of a Gd(n,γ) calculation model and comparison with our experimental data taken at ANNRI/MLF beam line, J-PARC.

  5. Topical hemostatic agents: a review.

    PubMed

    Palm, Melanie D; Altman, Jeffrey S

    2008-04-01

    Topical hemostatic agents play an important role in both common and specialized dermatologic procedures. These agents can be classified based on their mechanism of action and include physical or mechanical agents, caustic agents, biologic physical agents, and physiologic agents. Some agents induce protein coagulation and precipitation resulting in occlusion of small cutaneous vessels, while others take advantage of latter stages in the coagulation cascade, activating biologic responses to bleeding. Traditional and newer topical hemostatic agents are discussed in this review, and the benefits and costs of each agent will be provided.

  6. Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12)

    PubMed Central

    Li, Ji-Guang; Sakka, Yoshio

    2015-01-01

    This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd3+ to the activator. Ce3+ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out. PMID:27877750

  7. Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12).

    PubMed

    Li, Ji-Guang; Sakka, Yoshio

    2015-02-01

    This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd(3+) to the activator. Ce(3+) doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.

  8. Gadolinium-Conjugated Gold Nanoshells for Multimodal Diagnostic Imaging and Photothermal Cancer Therapy

    PubMed Central

    Coughlin, Andrew J.; Ananta, Jeyarama S.; Deng, Nanfu; Larina, Irina V.; Decuzzi, Paolo

    2014-01-01

    Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated gold nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation. PMID:24115690

  9. Structural and optical properties of Nd{sup 3+} doped gadolinium oxide 1D nanorods

    SciTech Connect

    Boopathi, G. Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    Neodymium doped gadolinium hydroxide [Nd:Gd(OH)3] nanorods were successfully synthesized at 60 °C through co-precipitation method. The dopant percentage was maintained at 5% and calcination was done at 750 °C temperature for 1 hour to form the respective neodymium doped gadolinium oxide [Nd:Gd{sub 2}O{sub 3}] nanorods. The as-formed and annealed products were investigated in detail by using powder X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) with an energy dispersive X-ray spectrum (EDX), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectrophotometry.

  10. Misconnections in the Critically Ill: Injection of High-Dose Gadolinium into an External Ventricular Drain.

    PubMed

    Singh, Sumit; Rejai, Sepehr; Antongiorgi, Zarah; Gonzalez, Nestor; Stelzner, Matthias

    2016-03-01

    We report an unfortunate case of accidental administration of intrathecal gadolinium through an external ventricular drain in a postcraniotomy patient during magnetic resonance imaging of the brain. The incident occurred after the venous contrast line was connected mistakenly to the ventricular drainage catheter. The patient subsequently developed confusion, aphasia, and right facial droop with new computed tomography evidence of diffuse cerebral edema and stroke. Review of the magnetic resonance image revealed the inappropriate presence of subarachnoid gadolinium. Despite all interventions, the patient developed irreversible neurologic disability. We address the clinical sequelae, management strategies, and factors contributing to the catheter misconnection that led to this event.

  11. Structural, morphological and optical investigations on Sm{sup 3+} doped gadolinium oxide nanorods

    SciTech Connect

    Boopathi, G.; Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    One dimensional uniform Sm{sup 3+} doped gadolinium hydroxide nanorods have been prepared via simple co– precipitation technique at 60 °C temperature for 1 hour. The samples were calcinated at 750 °C to obtain Sm{sup 3+} doped gadolinium oxide nanorods. The 1D nanorods were then subjected to different characterization techniques to ascertain its structural stability and its morphology were investigated using high–resolution transmission electron microscopy. Photoluminescence (PL) spectrophotometry was investigated and the obtained results were discussed in detail.

  12. Gadolinium-conjugated gold nanoshells for multimodal diagnostic imaging and photothermal cancer therapy.

    PubMed

    Coughlin, Andrew J; Ananta, Jeyarama S; Deng, Nanfu; Larina, Irina V; Decuzzi, Paolo; West, Jennifer L

    2014-02-12

    Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, gadolinium-conjugated gold nanoshells are engineered and it is demonstrated that they enhance contrast for magnetic resonance imaging, X-ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation.

  13. Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents.

    PubMed

    Estelrich, Joan; Sánchez-Martín, María Jesús; Busquets, Maria Antònia

    2015-01-01

    Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T 1, spin-lattice relaxation and T 2, spin-spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T 1 and T 2 increases the corresponding relaxation rates, 1/T 1 and 1/T 2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T 2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T 1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

  14. Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

    PubMed Central

    Estelrich, Joan; Sánchez-Martín, María Jesús; Busquets, Maria Antònia

    2015-01-01

    Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T1, spin–lattice relaxation and T2, spin–spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T1 and T2 increases the corresponding relaxation rates, 1/T1 and 1/T2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents. PMID:25834422

  15. Discovery of 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride as a deoxofluorinating agent with high thermal stability as well as unusual resistance to aqueous hydrolysis, and its diverse fluorination capabilities including deoxofluoro-arylsulfinylation with high stereoselectivity.

    PubMed

    Umemoto, Teruo; Singh, Rajendra P; Xu, Yong; Saito, Norimichi

    2010-12-29

    Versatile, safe, shelf-stable, and easy-to-handle fluorinating agents are strongly desired in both academic and industrial arenas, since fluorinated compounds have attracted considerable interest in many areas, such as drug discovery, due to the unique effects of fluorine atoms when incorporated into molecules. This article describes the synthesis, properties, and reactivity of many substituted and thermally stable phenylsulfur trifluorides, in particular, 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Fluolead, 1k), as a crystalline solid having surprisingly high stability on contact with water and superior utility as a deoxofluorinating agent compared to current reagents, such as DAST and its analogues. The roles of substituents on 1k in thermal and hydrolytic stability, fluorination reactivity, and the high-yield fluorination mechanism it undergoes have been clarified. In addition to fluorinations of alcohols, aldehydes, and enolizable ketones, 1k smoothly converts non-enolizable carbonyls to CF(2) groups, and carboxylic groups to CF(3) groups, in high yields. 1k also converts C(=S) and CH(3)SC(=S)O groups to CF(2) and CF(3)O groups, respectively, in high yields. In addition, 1k effects highly stereoselective deoxofluoro-arylsulfinylation of diols and amino alcohols to give fluoroalkyl arylsulfinates and arylsulfinamides, with complete inversion of configuration at fluorine and the simultaneous, selective formation of one conformational isomer at the sulfoxide sulfur atom. Considering the unique and diverse properties, relative safety, and ease of handling of 1k in addition to its convenient synthesis, it is expected to find considerable use as a novel fluorinating agent in both academic and industrial arenas.

  16. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    SciTech Connect

    Deli, Martin; Mateiescu, Serban Busch, Martin; Becker, Jan Garmer, Marietta Groenemeyer, Dietrich

    2013-06-15

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  17. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  18. Syntheses, structures, magnetism, and optical properties of gadolinium scandium chalcogenides

    SciTech Connect

    Jin Gengbang; Choi, Eun Sang; Albrecht-Schmitt, Thomas E.

    2009-05-15

    Three gadolinium scandium chalcogenides have been synthesized using Sb{sub 2}Q{sub 3} (Q=S, Se) fluxes at 975 deg. C. Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are crystallized in U{sub 3}ScS{sub 6} type, GdFeO{sub 3} type, and UFeS{sub 3} type structures, respectively. The magnetic susceptibilities for these compounds follow the Curie-Weiss law above their transition temperatures. The effective magnetic moments are close to calculated values for free Gd{sup 3+} ions. The Weiss constants for Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are determined to be -3.3(1), -4.5(4), and 1.5(1) K, respectively. Gd{sub 3.04}Sc{sub 0.96}S{sub 6} orders antiferromagnetically below 9 K. GdScS{sub 3} exhibits an antiferromagnetic ordering below 3 K with a weak ferromagnetism. Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} undergoes a ferromagnetic transition around 5 K. The optical band gaps for Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are 1.5, 2.1, and 1.2 eV, respectively. - Graphical abstract: A view of the three-dimensional structure of Gd{sub 3.04}Sc{sub 0.96}S{sub 6} along the c axis.

  19. High-Relaxivity MRI Contrast Agents: Where Coordination Chemistry Meets Medical Imaging

    SciTech Connect

    Werner, Eric J.; Datta, Ankona; Jocher, Christoph J.; Raymond, Kenneth N.

    2008-01-15

    The desire to improve and expand the scope of clinical magnetic resonance imaging (MRI) has prompted the search for contrast agents of higher efficiency. The development of better agents requires consideration of the fundamental coordination chemistry of the gadolinium(III) ion and the parameters that affect its efficacy as a proton relaxation agent. In optimizing each parameter, other practical issues such as solubility and in vivo toxicity must also be addressed, making the attainment of safe, high-relaxivity agents a challenging goal. Here we present recent advances in the field, with an emphasis on the hydroxypyridinone family of Gd{sup III} chelates.

  20. Preparation of 152Gd targets from a small quantity of gadolinium oxide in a pyrochemical reaction

    NASA Astrophysics Data System (ADS)

    Lipski, A. R.

    1995-02-01

    A simple method utilizing small amounts (< 5 mg) of isotopically enriched material for the production of gadolinium targets is discussed. An electrostatically focused e-gun is used in the procedure in which 152Gd 2O 3 powder undergoes reduction-distillation and deposition onto an Fe foil.

  1. Lithium Gadolinium Borate in Plastic Scintillator as an Antineutrino Detection Material

    DTIC Science & Technology

    2010-06-01

    techniques, such as tags, seals, and tamper proof video cameras , but no direct measurement of the fission process [7]. In smaller research...inverse beta interaction is captured by a gadolinium nucleus, producing multiple gamma rays. These gamma rays in turn generate fast Compton -scattered...electrons,2 which generate a second flash of Cerenkov light. This design has only been 2 Compton

  2. Criticality experiments with low enriched UO/sub 2/ fuel rods in water containing dissolved gadolinium

    SciTech Connect

    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/sub 2/ and PuO/sub 2/-UO/sub 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/sub 2/ rods at two enrichments (2.35 wt % and 4.31 wt % /sup 235/U) and on mixed fuel-water assemblies of UO/sub 2/ and PuO/sub 2/-UO/sub 2/ rods containing 4.31 wt % /sup 235/U and 2 wt % PuO/sub 2/ in natural UO/sub 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 /sup 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.

  3. Indirect MR lymphangiography of the head and neck using conventional gadolinium contrast: A pilot study in humans

    SciTech Connect

    Loo, Billy W. . E-mail: BWLoo@Stanford.edu; Draney, Mary T.; Sivanandan, Ranjiv; Ruehm, Stefan G.; Pawlicki, Todd; Xing Lei; Herfkens, Robert J.; Le, Quynh-Thu

    2006-10-01

    Purpose: To evaluate indirect magnetic resonance lymphangiography (MR-LAG) using interstitial injection of conventional gadolinium contrast (gadoteridol and gadopentetate dimeglumine) for delineating the primary lymphatic drainage of head-and-neck sites. Methods and Materials: We performed head-and-neck MR-LAG in 5 healthy volunteers, with injection of dermal and mucosal sites. We evaluated the safety of the procedure, the patterns of enhancement categorized by injection site and nodal level, the time course of enhancement, the optimal concentration and volume of contrast, and the optimal imaging sequence. Results: The worst side effects of interstitial contrast injection were brief, mild pain and swelling at the injected sites that were self-limited. MR-LAG resulted in consistent visualization of the primary lymphatic drainage pattern specific to each injected site, which was reproducible on repeated examinations. The best enhancement was obtained with injection of small volumes (0.3-0.5 mL) of either agent diluted, imaging within 5-15 min of injection, and a three-dimensional fast spoiled gradient echo sequence with magnetization transfer. Conclusions: We found head-and-neck MR-LAG to be a safe, convenient imaging method that provides functional information about the lymphatic drainage of injected sites. Applied to head-and-neck cancer, it has the potential to identify sites at highest risk of occult metastatic spread for radiotherapy or surgical planning, and possibly to visualize micrometastases.

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

    PubMed

    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.

  5. A benchmarked MCNP model of the in vivo detection of gadolinium by prompt gamma neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Gräfe, J. L.; McNeill, F. E.; Byun, S. H.; Chettle, D. R.; Noseworthy, M. D.

    2010-08-01

    Gadolinium (Gd)-based contrast agents are a valuable diagnostic aid for magnetic resonance imaging (MRI). The amount of free Gd deposited in tissues following contrast enhanced MRI is of toxicological concern. The McMaster University in vivo prompt gamma neutron activation analysis facility has been adapted for the detection of Gd in the kidney, liver, and the leg muscle. A simple model of the HPGe detector used for detection of the prompt γ-rays following Gd neutron capture has been created using Monte Carlo simulation. A separate simulation describing the neutron collimation and shielding apparatus has been modified to determine the neutron capture rate in the Gd phantoms. The MCNP simulation results have been confirmed by experimental measurement. The deviations between MCNP and the experiment were between 1% and 18%, with an average deviation of 3.8 ± 6.7%. The validated MCNP model is to be used to improve the Gd in vivo measurement sensitivity by determining the best neutron moderator/reflector arrangement.

  6. Automated scanning electron microscopy and x-ray microanalysis for in situ quantification of gadolinium deposits in skin.

    PubMed

    Thakral, Charu; Abraham, Jerrold L

    2007-10-01

    Gadolinium (Gd) has been identified as a possible causative agent of an emerging cutaneous and systemic fibrosing disorder, nephrogenic systemic fibrosis (NSF), which can cause serious disability and even death. To date, there are only two known associations with this disorder--renal insufficiency and Gd enhanced magnetic resonance imaging (MRI). We developed an automated quantitative scanning electron microscopy (SEM) and Energy dispersive x-ray spectroscopy (EDS) method for Gd in tissue of NSF patients. Freshly cut paraffin block surfaces examined using the variable pressure mode under standardized conditions and random search of the tissue area allow in situ detection and semiquantitative morphometric (volumetric) analysis of insoluble higher atomic number features using backscattered electron imaging. We detected Gd ranging from 1 to 2270 cps/mm2 in 57 cutaneous biopsies of NSF. Gd was associated with P, Ca, and usually Na in tissue deposits. Our method reproducibly determines the elemental composition, relative concentration, and spatial distribution of detected features within the tissue. However, we cannot detect features below our spatial resolution, nor concentrations below the detection limit of our SEM/EDS system. The findings confirm transmetallation and release of toxic Gd ions in NSF and allow dose-response analysis at the histologic level.

  7. Immediate Adverse Reactions to Gadolinium-Based MR Contrast Media: A Retrospective Analysis on 10,608 Examinations

    PubMed Central

    Fusco, Roberta; dell'Aprovitola, Nicoletta; Catalano, Orlando; Filice, Salvatore; Schiavone, Vincenzo; Izzo, Francesco; Cuomo, Arturo

    2016-01-01

    Background and Purpose. Contrast media (CM) for magnetic resonance imaging (MRI) may determine the development of acute adverse reactions. Objective was to retrospectively assess the frequency and severity of adverse reactions associated with gadolinium-based contrast agents (GBCAs) injection in patients who underwent MRI. Material and Methods. At our center 10608 MRI examinations with CM were performed using five different GBCAs: Gd-BOPTA (MultiHance), Gd-DTPA (Magnevist), Gd-EOBDTPA (Primovist), Gd-DOTA (Dotarem), and Gd-BTDO3A (Gadovist). Results. 32 acute adverse reactions occurred, accounting for 0.3% of all administration. Twelve reactions were associated with Gd-DOTA injection (0.11%), 9 with Gd-BOPTA injection (0.08%), 6 with Gd-BTDO3A (0.056%), 3 with Gd-EOB-DTPA (0.028%), and 2 with Gd-DTPA (0.018%). Twenty-four reactions (75.0%) were mild, four (12.5%) moderate, and four (12.5%) severe. The most severe reactions were seen associated with use of Gd-BOPTA, with 3 severe reactions in 32 total reactions. Conclusion. Acute adverse reactions are generally rare with the overall adverse reaction rate of 0.3%. The most common adverse reactions were not severe, consisting in skin rash and hives. PMID:27652261

  8. Gadolinium(III)-Chelated Silica Nanospheres Integrating Chemotherapy and Photothermal Therapy for Cancer Treatment and Magnetic Resonance Imaging.

    PubMed

    Cao, Mingjing; Wang, Pengyang; Kou, Yu; Wang, Jing; Liu, Jing; Li, Yanhui; Li, Jiayang; Wang, Liming; Chen, Chunying

    2015-11-18

    The combination of therapy and diagnosis has been emerging as a promising strategy for cancer treatment. To realize chemotherapy, photothermal therapy, and magnetic resonance imaging (MRI) in one system, we have synthesized a new magnetic nanoparticle (Gd@SiO2-DOX/ICG-PDC) integrating doxorubicin (DOX), indocyanine green (ICG), and gadolinium(III)-chelated silica nanospheres (Gd@SiO2) with a poly(diallyldimethylammonium chloride) (PDC) coating. PDC coating serves as a polymer layer to protect from quick release of drugs from the nanocarriers and increase cellular uptake. The DOX release from Gd@SiO2-DOX/ICG-PDC depends on pH and temperature. The process will be accelerated in the acidic condition than in a neutral pH 7.4. Meanwhile, upon laser irradiation, the photothermal effects promote DOX release and improve the therapeutic efficacy compared to either DOX-loaded Gd@SiO2 or ICG-loaded Gd@SiO2. Moreover, MRI results show that the Gd@SiO2-PDC nanoparticles are safe T1-type MRI contrast agents for imaging. The Gd@SiO2-PDC nanoparticles loaded with DOX and ICG can thus act as a promising theranostic platform for multimodal cancer treatment.

  9. A new method for the determination of Gadolinium in ppq levels

    NASA Astrophysics Data System (ADS)

    Brünjes, Robert; Bichler, Andrea; Hofmann, Thilo

    2015-04-01

    The use of Gadolinium (Gd) complexes as a contrast agent in Magnetic Resonance Imaging (MRI) results in an enhanced Gd input in the aquatic environment. Gd-complexes are excreted by humans unmetabolized within 12h after application. Passing the sewage systems with almost no degradation taking place, they successively reach surface waters, which make Gd a capable tracer for surface water/groundwater (SW/GW) interactions. The natural background concentration of Gd and other rare earth elements (REE) occur at ultratrace levels [low ng/L]. Crust-normalized REE patterns show positive Gd-anomalies in surface water, groundwater, and recently also in tap water. The difference between the total concentration and its natural background concentration estimated by the REE pattern is the anthropogenic Gd. Not only densely populated areas are affected by the presence of anthropogenic Gd. Studies have shown that even in rural areas without MRI facilities, anthropogenic Gd can be detected, since people are sent home after treatment. However, low input concentrations and mixing with natural waters lead to a decrease of Gd concentration below the current limit of quantification (LOQ) [1-5ng/L]. Often anthropogenic Gd cannot be calculated, although it is present, because natural background concentration cannot be determined with current methods, in particular in areas with low waste water load (e.g. headwater catchments). A new method using an on-line preconcentration system "SeaFAST" (Elemental Scientific Inc., USA), in combination with a desolvation system "Apex Q" (Elemental Scientific Inc., USA) and a QQQ-ICP-MS instrument (Agilent Technologies, Japan) does lower the LOQ for REE by a factor of 10 to 20. The SeaFAST-system uses a resin with ethylenediaminetriacetic acid and iminodiacetic acid functional groups to preconcentrate specifically REE as they are exclusively trivalent while anions, alkali and alkaline earth cations are washed out. The Apex Q interface is also supposed to

  10. Nickel-based Gadolinium Alloy for Neutron Adsorption Application in Ram Packages

    SciTech Connect

    Gregg Wachs; James Sterbentz; William Hurt; P. E. McConnell; C. V. Robino; F. Tovesson; T. S. Hill

    2007-10-01

    Neutron transmission experiments were performed on samples of an advanced nickel-chromium-molybdenum-gadolinium (Ni-Cr-Mo-Gd) neutron absorber alloy and chromium-nickel (Cr-Ni) stainless steel, modified by the addition of boron. The primary purpose of the experiments was to demonstrate the thermal neutron absorbing capability of the materials at specific gadolinium and boron dopant levels. The Ni-Cr-Mo-Gd alloy is envisioned to be deployed for criticality control of highly enriched U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF). For these transmission experiments, test samples were fabricated with 0.0, 1.58 and 2.1 wt% natural gadolinium dispersed in a Ni-Cr-Mo base alloy and 1.16 wt% boron in stainless steel. The transmission experiments were successfully carried out at the Los Alamos Neutron Science Center (LANSCE). Measured data from the neutron transmission experiments were compared to calculated results derived from a simple exponential transmission formula using total neutron cross sections. Excellent agreement between the measured and calculated results demonstrated the expected strong thermal absorption capability of the gadolinium and boron elements and in addition, verified the measured elemental composition of the Ni-Cr-Mo-Gd alloy and borated stainless steel test samples. The good agreement also indirectly confirmed that the size and distribution of the gadolinium in both the hot-top (as-cast) and Ni-Cr-Mo-Gd converted to plate was not a discriminator related to neutron absorption. Moreover, the Evaluated Nuclear Data File (ENDF VII) total neutron cross section data were accurate.

  11. Encapsulated gadolinium and dysprosium ions within ultra-short carbon nanotubes for MR microscopy at 11.75 and 21.1 T.

    PubMed

    Rosenberg, Jens T; Cisneros, Brandon T; Matson, Michael; Sokoll, Michelle; Sachi-Kocher, Afi; Bejarano, Fabian Calixto; Wilson, Lon J; Grant, Samuel C

    2014-01-01

    Single-walled carbon nanotubes (SWNTs) have gained interest for their biocompatibility and multifunctional properties. Ultra-short SWNTs (US-tubes) have demonstrated high proton relaxivity when encapsulating gadolinium ions (Gd(3+)) at clinical field strengths. At higher field strengths, however, Gd(3+) ions demonstrate decreased proton relaxation properties while chemically similar dysprosium ions (Dy(3+)) improve relaxation properties. This report investigates the first use of Gd(3+) and Dy(3+) ions within US-tubes (GNTs and DNTs, respectively) at ultra-high magnetic field (21.1 T). Both agents are compared in solution and as an intracellular contrast agent labeling a murine microglia cell line (Bv2) immobilized in a tissue-mimicking agarose phantom using two high magnetic fields: 21.1 and 11.75 T. In solution at 21.1 T, results show excellent transverse relaxation; DNTs outperformed GNTs as a T(2) agent with measured r(2)/r(1) ratios of 247 and 47, respectively. Additionally, intracellular DNTs were shown to be a better T(2) agent than GNTs with higher contrast percentages and contrast-to-noise ratios. As such, this study demonstrates the potential of DNTs at high magnetic fields for cellular labeling and future in vivo, MRI-based cell tracking.

  12. Agent Orange

    MedlinePlus

    ... Index Agent Orange Agent Orange Home Facts about Herbicides Veterans' Diseases Birth Defects Benefits Exposure Locations Provider ... Orange Parkinson’s Awareness Month Were you exposed to herbicides during service and have Parkinson’s disease? You may ...

  13. Gadolinium-induced fibrosis is counter-regulated by CCN3 in human dermal fibroblasts: a model for potential treatment of nephrogenic systemic fibrosis.

    PubMed

    Riser, Bruce L; Bhagavathula, Narasimharao; Perone, Patricia; Garchow, Kendra; Xu, Yiru; Fisher, Gary J; Najmabadi, Feridoon; Attili, Durga; Varani, James

    2012-06-01

    We recently show that CCN3 is a counter-regulatory molecule for the pro-fibrotic protein CCN2, and a potentially novel fibrosis therapy. The goal of this study was to assess the role of CCN3 in fibroproliferative/fibrotic responses in human dermal fibroblasts exposed to Omniscan, one of the gadolinium-based contrast agents associated with development of nephrogenic systemic fibrosis (NSF) a rare but life-threatening disease thought to be complication of NMR diagnostics in renal impaired patients. Human dermal fibroblasts were exposed to Omniscan; or to platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) as controls. Proliferation was assessed along with matrix metalloproteinase-1, tissue inhibitor of metalloproteinases-1 and type 1 procollagen in the absence and presence of CCN3. In parallel, CCN3 production was assessed in control and Omniscan-treated cells. The results showed that PDGF stimulated fibroblast proliferation, production of Timp-1 and MMP-1 whereas exogenous CCN3 inhibited, in a dose response manner, cell proliferation (approx. 50 % max.) and production of MMP-1 (approx 35 % max.) but had little effect on TIMP-1. TGF-β stimulated type 1 procollagen production but not proliferation, Timp-1 or MMP-1 compared to non-TGF-ß treated control cells, and CCN3 treatment blocked (approx. 80 % max.) this up-regulation. Interestingly, untreated, control fibroblasts produced high constitutive levels of CCN3 and concentrations of Omniscan that induced fibroproliferative/fibrogenic changes in dermal fibroblasts correspondingly suppressed CCN3 production. The use of PDGF and TGF-β as positive controls, and the study of differential responses, including that to Omniscan itself, provide the first evidence for a role of fibroblast-derived CCN3 as an endogenous regulator of pro-fibrotic changes, elucidating possible mechanism(s). In conclusion, these data support our hypothesis of a role for fibroblast-derived CCN3 as an endogenous

  14. Gadolinium-functionalized nanographene oxide for combined drug and microRNA delivery and magnetic resonance imaging.

    PubMed

    Yang, Hung-Wei; Huang, Chiung-Yin; Lin, Chih-Wen; Liu, Hao-Li; Huang, Chia-Wen; Liao, Shih-Sheng; Chen, Pin-Yuan; Lu, Yu-Jen; Wei, Kuo-Chen; Ma, Chen-Chi M

    2014-08-01

    The delivery of anti-cancer therapeutics to tumors at clinically effective concentrations, while avoiding nonspecific toxicity, remains a major challenge for cancer treatment. Here we present nanoparticles of poly(amidoamine) dendrimer-grafted gadolinium-functionalized nanographene oxide (Gd-NGO) as effective carriers to deliver both chemotherapeutic drugs and highly specific gene-targeting agents such as microRNAs (miRNAs) to cancer cells. The positively charged surface of Gd-NGO was capable of simultaneous adsorption of the anti-cancer drug epirubicin (EPI) and interaction with negatively charged Let-7g miRNA. Using human glioblastoma (U87) cells as a model, we found that this conjugate of Let-7g and EPI (Gd-NGO/Let-7g/EPI) not only exhibited considerably higher transfection efficiency, but also induced better inhibition of cancer cell growth than Gd-NGO/Let-7g or Gd-NGO/EPI. The concentration of Gd-NGO/Let-7g/EPI required for 50% inhibition of cellular growth (IC50) was significantly reduced (to the equivalent of 1.3 μg/mL EPI) compared to Gd-NGO/EPI (3.4 μg/mL EPI). In addition, Gd-NGO/Let-7g/EPI could be used as a contrast agent for magnetic resonance imaging to identify the location and extent of blood-brain barrier opening and quantitate drug delivery to tumor tissues. These results suggest that Gd-NGO/Let-7g/EPI may be a promising non-viral vector for chemogene therapy and molecular imaging diagnosis in future clinical applications.

  15. Inorganic nanocrystals as contrast agents in MRI:synthesis, coating and introducing multifunctionality

    PubMed Central

    Sanchez-Gaytan, Brenda L.; Mieszawska, Aneta J.; Fayad, Zahi A.

    2013-01-01

    Inorganic nanocrystals have myriad applications in medicine, which includes their use as drug or gene delivery complexes, therapeutic hyperthermia agents, in diagnostic systems and as contrast agents in a wide range of medical imaging techniques. For MRI, nanocrystals can produce contrast themselves, of which iron oxides have been most extensively explored, or be given a coating that generates MR contrast, for example gold nanoparticles coated with gadolinium chelates. These MR-active nanocrystals can be used in imaging of the vasculature, liver and other organs, as well as molecular imaging, cell tracking and theranostics. Due to these exciting applications, synthesizing and rendering these nanocrystals water-soluble and biocompatible is therefore highly desirable. We will discuss aqueous phase and organic phase methods for synthesizing inorganic nanocrystals such as gold, iron oxides and quantum dots. The pros and cons of the various methods will be highlighted. We explore various methods for making nanocrystals biocompatible, i.e. directly synthesizing nanocrystals coated with biocompatible coatings, ligand substitution, amphiphile coating and embedding in carrier matrices that can be made biocompatible. Various examples will be highlighted and their applications explained. These examples signify that synthesizing biocompatible nanocrystals with controlled properties has been achieved by numerous research groups and can be applied for a wide range of applications. Therefore we expect to see reports of preclinical applications of ever more complex MRI-active nanoparticles and their wider exploitation, as well as in novel clinical settings. PMID:23303729

  16. Removal of magnetic resonance imaging contrast agents through advanced water treatment plants.

    PubMed

    Lawrence, Michael G; Keller, Jurg; Poussade, Yvan

    2010-01-01

    Stable gadolinium (Gd) complexes have been used as paramagnetic contrast agents for magnetic resonance imaging (MRI) for over 20 years, and have recently been identified as environmental contaminants. As the rare earth elements (REE), which include Gd, are able to be measured accurately at very low concentrations (e.g. Tb is measured at 7 fmol/kg in this study) using inductively coupled plasma mass spectrometry (ICP-MS), it is possible to determine the fate of this class of compounds during the production of purified recycled water from effluent. Coagulation and microfiltration have negligible removal, with the major removal step occurring across the reverse osmosis membrane where anthropogenic Gd (the amount of Gd attributable to MRI contrast agents) is reduced from 0.39 nmol/kg to 0.59 pmol/kg, a reduction of 99.85%. The RO concentrate has anthropogenic Gd concentrations of 2.6 nmol/kg, an increase in concentration in line with the design characteristics of the plant. The increased concentration in the RO concentrate may allow further development of anthropogenic Gd as a tracer of the fate of the RO concentrate in the environment.

  17. First measurements with new high-resolution gadolinium-GEM neutron detectors

    NASA Astrophysics Data System (ADS)

    Pfeiffer, D.; Resnati, F.; Birch, J.; Etxegarai, M.; Hall-Wilton, R.; Höglund, C.; Hultman, L.; Llamas-Jansa, I.; Oliveri, E.; Oksanen, E.; Robinson, L.; Ropelewski, L.; Schmidt, S.; Streli, C.; Thuiner, P.

    2016-05-01

    European Spallation Source instruments like the macromolecular diffractometer (NMX) require an excellent neutron detection efficiency, high-rate capabilities, time resolution, and an unprecedented spatial resolution in the order of a few hundred micrometers over a wide angular range of the incoming neutrons. For these instruments solid converters in combination with Micro Pattern Gaseous Detectors (MPGDs) are a promising option. A GEM detector with gadolinium converter was tested on a cold neutron beam at the IFE research reactor in Norway. The μTPC analysis, proven to improve the spatial resolution in the case of 10B converters, is extended to gadolinium based detectors. For the first time, a Gd-GEM was successfully operated to detect neutrons with a measured efficiency of 11.8% at a wavelength of 2 Åand a position resolution better than 250 μm.

  18. The statistical decay properties of Gadolinium isotopes using the DANCE array

    NASA Astrophysics Data System (ADS)

    Dashdorj, D.; Mitchell, G.; Baramsai, B.; Chankova, R.; Chyzh, A.; Walker, C.

    2008-10-01

    The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. There are seven stable isotopes of gadolinium with varying deformation. Decay γ rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable γ-ray multiplicity measurements. The calorimetric property of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles γ-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.

  19. Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media.

    PubMed

    Canga, Ana; Kislikova, Maria; Martínez-Gálvez, María; Arias, Mercedes; Fraga-Rivas, Patricia; Poyatos, Cecilio; de Francisco, Angel L M

    2014-01-01

    Nephrogenic systemic fibrosis is a fibrosing disorder that affects patients with impaired renal function and is associated with the administration of gadolinium-based contrast media used in MRI. Despite being in a group of drugs that were considered safe, report about this potentially serious adverse reaction was a turning point in the administration guidelines of these contrast media. There has been an attempt to establish safety parameters to identify patients with risk factors of renal failure. The close pharmacovigilance and strict observation of current regulations, with special attention being paid to the value of glomerular filtration, have reduced the published cases involving the use of gadolinium-based contrast media. In a meeting between radiologists and nephrologists we reviewed the most relevant aspects currently and recommendations for its prevention.

  20. Thermodynamic property evaluation and magnetic refrigeration cycle analysis for gadolinium gallium garnet

    SciTech Connect

    Murphy, R.W.

    1994-12-01

    Based on relevant material property data and previous model formulations, a magnetothermodynamic property map for gadolinium gallium garnet (Gd{sub 3}Ga{sub 5}O{sub 12}) was adapted for refrigeration cycle analysis in the temperature range 4-40 K and the magnetic field range 0-6 T. Employing methods similar to those previously developed for other materials and temperature ranges, assessments of limitations and relative performance were made for Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. It was found that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as the limitations for materials previously examined, considerable improvement in cooling capacity and temperature lift combinations can be achieved by using regenerative cycles if serious loss mechanisms are avoided.

  1. A new gadolinium-loaded liquid scintillator for reactor neutrino detection

    NASA Astrophysics Data System (ADS)

    Ding, Yayun; Zhang, Zhiyong; Liu, Jinchang; Wang, Zhimin; Zhou, Pengju; Zhao, Yuliang

    2008-01-01

    A high flash point, low toxicity gadolinium-loaded liquid scintillator (Gd-LS) has been developed for the detection of reactor neutrino. Carboxylic acid 3,5,5-trimethylhexanoic acid is used as complexing ligand to form organo-complex with gadolinium chloride, and 2,5-diphenyloxazole (PPO), and 1,4-bis[2-methylstyryl]benzene (bis-MSB) are used as primary fluor and wavelength shifter, respectively. The scintillator base is linear alkyl benzene (LAB). The Gd-LS prepared with such recipe has long attenuation length, high light yield and long-term stability. Eight hundred liters of Gd-LS (1 g/L Gd) was synthesized and tested in a prototype detector at Institute of High Energy Physics. Preliminary results of the obviously peaks corresponding to neutron captured by H and Gd give an additional evidence that such Gd-LS are very promising for anti-neutrino detection.

  2. Quantitative measurement of regional blood flow with gadolinium diethylenetriaminepentaacetate bolus track NMR imaging in cerebral infarcts in rats: validation with the iodo[14C]antipyrine technique.

    PubMed Central

    Wittlich, F; Kohno, K; Mies, G; Norris, D G; Hoehn-Berlage, M

    1995-01-01

    NMR bolus track measurements were correlated with autoradiographically determined regional cerebral blood flow (rCBF). The NMR method is based on bolus infusion of the contrast agent gadolinium diethylenetriaminepentaacetate and high-speed T*2-sensitive NMR imaging. The first pass of the contrast agent through the image plane causes a transient decrease of the signal intensity. This time course of the signal intensity is transformed into relative concentrations of the contrast agent in each pixel. The mean transit time and relative blood flow and volume are calculated from such indicator dilution curves. We investigated whether this NMR technique correctly expresses the relative rCBF. The relative blood flow data, calculated from NMR bolus track experiments, and the absolute values of iodo[14C]antipyrine autoradiography were compared. A linear relationship was observed, indicating the proportionality of the transient NMR signal change with CBF. Excellent interindividual reproducibility of calibration constants is observed (r = 0.963). For a given NMR protocol, bolus track measurements calibrated with autoradiography after the experiment allow determination of absolute values for rCBF and regional blood volume. Images Fig. 2 Fig. 3 PMID:7892189

  3. Curcumin Targeted, Polymalic Acid-Based MRI Contrast Agent for the Detection of Aβ Plaques in Alzheimer's Disease.

    PubMed

    Patil, Rameshwar; Gangalum, Pallavi R; Wagner, Shawn; Portilla-Arias, Jose; Ding, Hui; Rekechenetskiy, Arthur; Konda, Bindu; Inoue, Satoshi; Black, Keith L; Ljubimova, Julia Y; Holler, Eggehard

    2015-09-01

    Currently, there is no gadolinium-based contrast agent available for conventional magnetic resonance imaging (MRI) detection of amyloidal beta (Aβ) plaques in Alzheimer's disease (AD). Its timely finding would be vital for patient survival and quality of life. Curcumin (CUR), a common Indian spice effectively binds to Aβ plaques which is a hallmark of AD. To address this binding, we have designed a novel nanoimaging agent (NIA) based on nature-derived poly(β-l-malic acid) (PMLA) containing covalently attached gadolinium-DOTA(Gd-DOTA) and nature-derived CUR. The all-in-one agent recognizes and selectively binds to Aβ plaques and is detected by MRI. It efficiently detected Aβ plaques in human and mouse samples by an ex vivo staining. The method can be useful in clinic for safe and noninvasive diagnosis of AD.

  4. Highly absorbing gadolinium test device to characterize the performance of neutron imaging detector systems

    SciTech Connect

    Gruenzweig, C.; Frei, G.; Lehmann, E.; Kuehne, G.; David, C.

    2007-05-15

    We report on the fabrication and application of a novel neutron imaging test device made of gadolinium. It is designed for a real time evaluation of the spatial resolution, resolution direction, and distortions of a neutron imaging detector system. Measurements of the spatial resolution of {sup 6}LiF doped ZnS scintillator screens with different thicknesses and of imaging plates were performed. The obtained results are in good agreement with comparison measurements using the standard knife edge detection method.

  5. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

    SciTech Connect

    Enger, Shirin A.; Rezaei, Arash; Munck af Rosenschoeld, Per; Lundqvist, Hans

    2006-01-15

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel.

  6. Proposed experiment to measure {gamma}-rays from the thermal neutron capture of gadolinium

    SciTech Connect

    Yano, Takatomi; Ou, I.; Izumi, T.; Yamaguchi, R.; Mori, T.; Sakuda, M.

    2012-11-12

    Gadolinium-157 ({sup 157}Gd) has the largest thermal neutron capture cross section among any stable nuclei. The thermal neutron capture yields {gamma}-ray cascade with total energy of about 8 MeV. Because of these characteristics, Gd is applied for the recent neutrino detectors. Here, we propose an experiment to measure the multiplicity and the angular correlation of {gamma}-rays from the Gd neutron capture. With these information, we expect the improved identification of the Gd neutron capture.

  7. Gadolinium Oxide / Silicon Thin Film Heterojunction Solid-State Neutron Detector

    DTIC Science & Technology

    2010-03-01

    gadolinium oxide (Gd2O3) and p-type silicon heterojunction diodes were produced using a supercritical water deposition process . Pulse height spectroscopy...possible to produce semi-conductor devices that have a high probability of neutron interaction. 1.2 Problem Statement Can a heterojunction diode...materials. The second area develops a method of depositing Gd on silicon with subsequent device fabrication. The third is a feasibility study that

  8. Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

    2013-03-01

    We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential. Electronic supplementary information

  9. Efficacy and Safety of AFN-1252, the First Staphylococcus-Specific Antibacterial Agent, in the Treatment of Acute Bacterial Skin and Skin Structure Infections, Including Those in Patients with Significant Comorbidities

    PubMed Central

    Kaplan, N.; Murphy, B.

    2015-01-01

    This open-label noncontrolled, phase II multicenter trial was designed to evaluate the safety, tolerability, and efficacy of 200 mg of AFN-1252, a selective inhibitor of Staphylococcus aureus enoyl-acyl carrier protein reductase (FabI), given by mouth twice daily in the treatment of acute bacterial skin and skin structure infections (ABSSSI) due to staphylococci. Important aspects of the current study included a comparison of early response efficacy endpoints with end-of-treatment and follow-up endpoints. Many patients in the intent-to-treat population (n = 103) had significant comorbidities. The overall early response rate at day 3 was 97.3% (wound, 100%; abscess, 96.6%; cellulitis, 94.4%) in the microbiologically evaluable (ME) population. Within the ME population, 82.9% of patients had a ≥20% decrease in the area of erythema, and 77.9% of patients had a ≥20% decrease in the area of induration, on day 3. S. aureus was detected in 97.7% of patients (n = 37 patients with methicillin-resistant S. aureus [MRSA], and n = 39 with methicillin-sensitive S. aureus [MSSA]). No isolates had increased AFN-1252 MICs posttreatment. Microbiologic eradication rates for S. aureus were 93.2% at short-term follow-up (STFU) and 91.9% at long-term follow-up (LTFU) in the ME population. Eradication rates for MRSA and MSSA were 91.9% and 92.3%, respectively, at STFU and 91.9% and 89.7%, respectively, at LTFU. The most frequently reported drug-related adverse events, which were mostly mild or moderate, were headache (26.2%) and nausea (21.4%). These studies demonstrate that AFN-1252 is generally well tolerated and effective in the treatment of ABSSSI due to S. aureus, including MRSA. (This study has been registered at ClinicalTrials.gov under registration no. NCT01519492.) PMID:26711777

  10. Efficacy and Safety of AFN-1252, the First Staphylococcus-Specific Antibacterial Agent, in the Treatment of Acute Bacterial Skin and Skin Structure Infections, Including Those in Patients with Significant Comorbidities.

    PubMed

    Hafkin, B; Kaplan, N; Murphy, B

    2015-12-28

    This open-label noncontrolled, phase II multicenter trial was designed to evaluate the safety, tolerability, and efficacy of 200 mg of AFN-1252, a selective inhibitor of Staphylococcus aureus enoyl-acyl carrier protein reductase (FabI), given by mouth twice daily in the treatment of acute bacterial skin and skin structure infections (ABSSSI) due to staphylococci. Important aspects of the current study included a comparison of early response efficacy endpoints with end-of-treatment and follow-up endpoints. Many patients in the intent-to-treat population (n = 103) had significant comorbidities. The overall early response rate at day 3 was 97.3% (wound, 100%; abscess, 96.6%; cellulitis, 94.4%) in the microbiologically evaluable (ME) population. Within the ME population, 82.9% of patients had a ≥ 20% decrease in the area of erythema, and 77.9% of patients had a ≥ 20% decrease in the area of induration, on day 3. S. aureus was detected in 97.7% of patients (n = 37 patients with methicillin-resistant S. aureus [MRSA], and n = 39 with methicillin-sensitive S. aureus [MSSA]). No isolates had increased AFN-1252 MICs posttreatment. Microbiologic eradication rates for S. aureus were 93.2% at short-term follow-up (STFU) and 91.9% at long-term follow-up (LTFU) in the ME population. Eradication rates for MRSA and MSSA were 91.9% and 92.3%, respectively, at STFU and 91.9% and 89.7%, respectively, at LTFU. The most frequently reported drug-related adverse events, which were mostly mild or moderate, were headache (26.2%) and nausea (21.4%). These studies demonstrate that AFN-1252 is generally well tolerated and effective in the treatment of ABSSSI due to S. aureus, including MRSA. (This study has been registered at ClinicalTrials.gov under registration no. NCT01519492.).

  11. Selective Filtration of Gadolinium Trichloride for Use in Neutron Detection in Large Water Cherenkov Detectors

    SciTech Connect

    Vagins, Mark R.

    2013-04-10

    Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have been investigating the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This focused study of selective water filtration and GdCl{sub 3} extraction techniques, conducted at UC Irvine, followed up on highly promising benchtop-scale and kiloton-scale work previously carried out with the assistance of 2003 and 2005 Advanced Detector Research Program grants.

  12. Study of the Photon Strength Functions for Gadolinium Isotopes with the DANCE Array

    NASA Astrophysics Data System (ADS)

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chankova, R.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krtička, M.; Bečvář, F.

    2009-03-01

    The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.

  13. Large Scale Testing and Development of Gadolinium Trichloride for Use in Neutron Detection in Large Water

    SciTech Connect

    Mark Vagine

    2007-09-18

    Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have begun to investigate the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This large-scale investigation, conducted in the one kiloton water Cherenkov detector built for the K2K long-baseline experiment, follows up on highly promising benchtop-scale work previously carried out with the assistance of a 2003 Advanced Detector Research Program grant.

  14. Study of the Photon Strength Functions for Gadolinium Isotopes with the DANCE Array

    SciTech Connect

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chankova, R.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krticka, M.

    2009-03-10

    The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.

  15. Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

    SciTech Connect

    Ogunlade, Olumide Beard, Paul

    2015-01-15

    Purpose: Thermoacoustic imaging at microwave excitation frequencies is limited by the low differential contrast exhibited by high water content tissues. To overcome this, exogenous thermoacoustic contrast agents based on gadolinium compounds, iron oxide, and single wall carbon nanotubes have previously been suggested and investigated. However, these previous studies did not fully characterize the electric, magnetic, and thermodynamic properties of these agents thus precluding identification of the underlying sources of contrast. To address this, measurements of the complex permittivity, complex permeability, DC conductivity, and Grüneisen parameter have been made. These measurements allowed the origins of the contrast provided by each substance to be identified. Methods: The electric and magnetic properties of the contrast agents were characterized at 3 GHz using two rectangular waveguide cavities. The DC conductivity was measured separately using a conductivity meter. Thermoacoustic signals were then acquired and compared to those generated in water. Finally, 3D electromagnetic simulations were used to decouple the different contributions to the absorbed power density. Results: It was found that the gadolinium compounds provided appreciable electric contrast but not originating from the gadolinium itself. The contrast was either due to dissociation of the gadolinium salt which increased ionic conductivity or its nondissociated polar fraction which increased dielectric polarization loss or a combination of both. In addition, very high concentrations were required to achieve appreciable contrast, to the extent that the Grüneisen parameter increased significantly and became a source of contrast. Iron oxide particles were found to produce low but measurable dielectric contrast due to dielectric polarization loss, but this is attributed to the coating of the particles not the iron oxide. Single wall carbon nanotubes did not provide measurable contrast of any type

  16. Gadolinium-148 and other spallation production cross section measurements for accelerator target facilities

    NASA Astrophysics Data System (ADS)

    Kelley, Karen Corzine

    At the Los Alamos Neutron Science Center accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research facility and the 1L target at the Lujan Center. The Department of Energy requires hazard classification analyses to be performed on these targets and places limits on certain radionuclide inventories in the targets to avoid characterizing the facilities as "nuclear facilities." Gadolinium-148 is a radionuclide created from the spallation of tungsten. Allowed isotopic inventories are particularly low for this isotope because it is an alpha-particle emitter with a 75-year half-life. The activity level of Gadolinium-148 is low, but it encompasses almost two-thirds of the total dose burden for the two tungsten targets based on present yield estimates. From a hazard classification standpoint, this severely limits the lifetime of these tungsten targets. The cross section is not well-established experimentally and this is the motivation for measuring the Gadolinium-148 production cross section from tungsten. In a series of experiments at the Weapons Neutron Research facility, Gadolinium-148 production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 mum thin tungsten, tantalum, and gold foils and 10 mum thin aluminum activation foils. In addition, spallation yields were determined for many short-lived and long-lived spallation products with these foils using gamma and alpha spectroscopy and compared with predictions of the Los Alamos National Laboratory codes CEM2k+GEM2 and MCNPX. The cumulative Gadolinium-148 production cross section measured from tantalum, tungsten, and gold for incident 600-MeV protons were 15.2 +/- 4.0, 8.31 +/- 0.92, and 0.591 +/- 0.155, respectively. The average production cross sections measured at 800 MeV were 28.6 +/- 3.5, 19.4 +/- 1.8, and 3.69 +/- 0.50 for tantalum, tungsten, and gold, respectively. These cumulative

  17. Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material

    SciTech Connect

    Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

    2004-12-14

    Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for surface

  18. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial Assistance for NMVC Companies (Leverage) Funding Leverage by Use of Sba Guaranteed Trust Certificates (âtcsâ... financial markets to determine those factors that will minimize or reduce the cost of funding...

  19. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial Assistance for NMVC Companies (Leverage) Funding Leverage by Use of Sba Guaranteed Trust Certificates (âtcsâ... financial markets to determine those factors that will minimize or reduce the cost of funding...

  20. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial Assistance for NMVC Companies (Leverage) Funding Leverage by Use of Sba Guaranteed Trust Certificates (âtcsâ... financial markets to determine those factors that will minimize or reduce the cost of funding...

  1. Agent oriented programming

    NASA Technical Reports Server (NTRS)

    Shoham, Yoav

    1994-01-01

    The goal of our research is a methodology for creating robust software in distributed and dynamic environments. The approach taken is to endow software objects with explicit information about one another, to have them interact through a commitment mechanism, and to equip them with a speech-acty communication language. System-level applications include software interoperation and compositionality. A government application of specific interest is an infrastructure for coordination among multiple planners. Daily activity applications include personal software assistants, such as programmable email, scheduling, and new group agents. Research topics include definition of mental state of agents, design of agent languages as well as interpreters for those languages, and mechanisms for coordination within agent societies such as artificial social laws and conventions.

  2. Preparation and characterization of gadolinium-loaded PLGA particles surface modified with RGDS for the detection of thrombus

    PubMed Central

    Zhang, Yu; Zhou, Jun; Guo, Dajing; Ao, Meng; Zheng, Yuanyi; Wang, Zhigang

    2013-01-01

    Thrombotic disease is a leading cause of death and disability worldwide. The development of magnetic resonance molecular imaging provides potential promise for early disease diagnosis. In this study, we explore the preparation and characterization of gadolinium (Gd)-loaded poly (lactic-co-glycolic acid) (PLGA) particles surface modified with the Arg-Gly-Asp-Ser (RGDS) peptide for the detection of thrombus. PLGA was employed as the carrier-delivery system, and a double emulsion solvent-evaporation method (water in oil in water) was used to prepare PLGA particles encapsulating the magnetic resonance contrast agent Gd diethylenetriaminepentaacetic acid (DTPA). To synthesize the Gd-PLGA/chitosan (CS)-RGDS particles, carbodiimide-mediated amide bond formation was used to graft the RGDS peptide to CS to form a CS-RGDS film that coated the surface of the PLGA particles. Blank PLGA, Gd-PLGA, and Gd-PLGA/CS particles were fabricated using the same water in oil in water method. Our results indicated that the RGDS peptide successfully coated the surface of the Gd-PLGA/CS-RGDS particles. The particles had a regular shape, smooth surface, relatively uniform size, and did not aggregate. The high electron density of the Gd-loaded particles and a translucent film around the particles coated with the CS and CS-RGDS films could be observed by transmission electron microscopy. In vitro experiments demonstrated that the Gd-PLGA/CS-RGDS particles could target thrombi and could be imaged using a clinical magnetic resonance scanner. Compared with the Gd-DTPA solution, the longitudinal relaxation time of the Gd-loaded particles was slightly longer, and as the Gd-load concentration increased, the longitudinal relaxation time values decreased. These results suggest the potential of the Gd-PLGA/CS-RGDS particles for the sensitive and specific detection of thrombus at the molecular level. PMID:24124363

  3. Manganese-based MRI contrast agents: past, present and future

    PubMed Central

    Pan, Dipanjan; Schmieder, Anne H.; Wickline, Samuel A.; Lanza, Gregory M.

    2011-01-01

    Paramagnetic and superparamagnetic metals are used as contrast materials for magnetic resonance (MR) based techniques. Lanthanide metal gadolinium (Gd) has been the most widely explored, predominant paramagnetic contrast agent until the discovery and association of the metal with nephrogenic systemic fibrosis (NSF), a rare but serious side effects in patients with renal or kidney problems. Manganese was one of the earliest reported examples of paramagnetic contrast material for MRI because of its efficient positive contrast enhancement. In this review, manganese based contrast agent approaches are discussed with a particular emphasis on their synthetic approaches. Both small molecules based typical blood pool contrast agents and more recently developed novel nanometer sized materials are reviewed focusing on a number of successful molecular imaging examples. PMID:22043109

  4. Safety assessment of nanoparamagnetic contrast agents with different coatings for molecular MRI

    NASA Astrophysics Data System (ADS)

    Azizian, Gholamreza; Riyahi-Alam, Nader; Haghgoo, Soheila; Saffari, Mojtaba; Zohdiaghdam, Reza; Gorji, Ensieh

    2013-04-01

    Despite the wide application of gadolinium as a contrast agent for magnetic resonance imaging (MRI), there is a serious lack of information on its toxicity. Gadolinium and gadolinium oxide (Gd-oxide) are used as contrast agents for magnetic resonance imaging (MRI). There are methods for reducing toxicity of these materials, such as core nanoparticles coating or conjugating. Therefore, for toxicity evaluation, we compared the viability of commercial contrast agents in MRI (Gd-DTPA) and three nanoparticles with the same core Gd2O3 and small particulate gadolinium oxide or SPGO (< 40 nm) but different coatings of diethyleneglycol (DEG) as Gd2O3-DEG and methoxy polyethylene glycol-silane (mPEG-silane: 550 and 2000 Dalton) as SPGO-mPEG-silane550 and SPGO-mPEG-silane2000, respectively, in the SK-MEL3 cell line, by light microscopy, MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity. The viability values were not statistically different between the three nanoparticles and Gd-DTPA. The MTT and LDH assay results showed that Gd2O3-DEG nanoparticles were more toxic than Gd-DTPA and other nanoparticles. Also, SPGO-mPEG-silane2000 was more biocompatible than other nanoparticles. The obtained results did not show any significant increase in cytotoxicity of the nanoparticles and Gd-DTPA, neither dose-dependent nor time-dependent. Therefore, DEG and PEG, due to their considerable properties and irregular sizes (different molecular weights), were selected as the useful surface covering materials of nanomagnetic particles that could reveal noticeable relaxivity and biocompatibility characteristics.

  5. Enhanced production of reactive oxygen species by gadolinium oxide nanoparticles under core-inner-shell excitation by proton or monochromatic X-ray irradiation: implication of the contribution from the interatomic de-excitation-mediated nanoradiator effect to dose enhancement.

    PubMed

    Seo, Seung-Jun; Han, Sung-Mi; Cho, Jae-Hoon; Hyodo, Kazuyuki; Zaboronok, Alexander; You, He; Peach, Ken; Hill, Mark A; Kim, Jong-Ki

    2015-11-01

    Core-inner-valence ionization of high-Z nanoparticle atomic clusters can de-excite electrons through various interatomic de-excitation processes, thereby leading to the ionization of both directly exposed atoms and adjacent neutral atoms within the nanoparticles, and to an enhancement in photon-electron emission, which is termed the nanoradiator effect. To investigate the nanoradiator-mediated dose enhancement in the radio-sensitizing of high-Z nanoparticles, the production of reactive oxygen species (ROS) was measured in a gadolinium oxide nanoparticle (Gd-oxide NP) solution under core-inner-valence excitation of Gd with either 50 keV monochromatic synchrotron X-rays or 45 MeV protons. This measurement was compared with either a radiation-only control or a gadolinium-chelate magnetic resonance imaging contrast agent solution containing equal amounts of gadolinium as the separate atomic species in which Gd-Gd interatomic de-excitations are absent. Ionization excitations followed by ROS measurements were performed on nanoparticle-loaded cells or aqueous solutions. Both photoexcitation and proton impact produced a dose-dependent enhancement in the production of ROS by a range of factors from 1.6 to 1.94 compared with the radiation-only control. Enhanced production of ROS, by a factor of 1.83, was observed from Gd-oxide NP atomic clusters compared with the Gd-chelate molecule, with a Gd concentration of 48 μg/mL in the core-level photon excitation, or by a factor of 1.82 under a Gd concentration of 12 μg/mL for the proton impact at 10 Gy (p < 0.02). The enhanced production of ROS in the irradiated nanoparticles suggests the potential for additional therapeutic dose enhancements in radiation treatment via the potent Gd-Gd interatomic de-excitation-driven nanoradiator effect.

  6. Antibiotic Agents

    MedlinePlus

    ... producing ). Examples of this type are the alcohols, chlorine, peroxides, and aldehydes. The second group consists mostly ... viruses have some kind of antibacterial agent. Alcohols, chlorine and peroxides have been used for many decades ...

  7. Agent Orange

    MedlinePlus

    ... Z) Hepatitis HIV Mental Health Mental Health Home Suicide Prevention Substance Abuse Military Sexual Trauma PTSD Research ( ... eligible Veterans a free Agent Orange Registry health exam for possible long-term health problems related to ...

  8. Does gadolinium-based contrast material improve diagnostic accuracy of local invasion in rectal cancer MRI? A multireader study.

    PubMed

    Gollub, Marc J; Lakhman, Yulia; McGinty, Katrina; Weiser, Martin R; Sohn, Michael; Zheng, Junting; Shia, Jinru

    2015-02-01

    OBJECTIVE. The purpose of this study was to compare reader accuracy and agreement on rectal MRI with and without gadolinium administration in the detection of T4 rectal cancer. MATERIALS AND METHODS. In this study, two radiologists and one fellow independently interpreted all posttreatment MRI studies for patients with locally advanced or recurrent rectal cancer using unenhanced images alone or combined with contrast-enhanced images, with a minimum interval of 4 weeks. Readers evaluated involvement of surrounding structures on a 5-point scale and were blinded to pathology and disease stage. Sensitivity, specificity, negative predictive value, positive predictive value, and AUC were calculated and kappa statistics were used to describe interreader agreement. RESULTS. Seventy-two patients (38 men and 34 women) with a mean age of 61 years (range, 32-86 years) were evaluated. Fifteen patients had 32 organs invaded. Global AUCs without and with gadolinium administration were 0.79 and 0.77, 0.91 and 0.86, and 0.83 and 0.78 for readers 1, 2, and 3, respectively. AUCs before and after gadolinium administration were similar. Kappa values before and after gadolinium administration for pairs of readers ranged from 0.5 to 0.7. CONCLUSION. On the basis of pathology as a reference standard, the use of gadolinium during rectal MRI did not significantly improve radiologists' agreement or ability to detect T4 disease.

  9. Quantitative assessment of the rheumatoid synovial microvascular bed by gadolinium-DTPA enhanced magnetic resonance imaging

    PubMed Central

    Gaffney, K.; Cookson, J.; Blades, S.; Coumbe, A.; Blake, D.

    1998-01-01

    OBJECTIVE—To examine the relation between rate of synovial membrane enhancement, intra-articular pressure (IAP), and histologically determined synovial vascularity in rheumatoid arthritis, using gadolinium-DTPA enhanced magnetic resonance imaging (MRI).
METHODS—Dynamic gadolinium-DTPA enhanced MRI was performed in 31 patients with knee synovitis (10 patients IAP study, 21 patients vascular morphometry study). Rate of synovial membrane enhancement was quantified by line profile analysis using the image processing package ANALYZE. IAP was measured using an intra-compartmental pressure monitor system. Multiple synovial biopsy specimens were obtained by a blind biopsy technique. Blood vessels were identified immunohistochemically using the endothelial cell marker QBend30 and quantified (blood vessel numerical density and fractional area).
RESULTS—Median blood vessel numerical density and fractional area were 77.5/mm2 (IQR; 69.3-110.7) and 5.6% (IQR; 3.4-8.5) respectively. The rate of synovial membrane enhancement (median 2.74 signal intensity units/s, IQR 2.0-3.8) correlated with both blood vessel numerical density (r = 0.46, p < 0.05) and blood vessel fractional area (r = 0.55, p < 0.02). IAP did not influence the rate of enhancement.
CONCLUSIONS—Gadolinium-DTPA enhanced MRI may prove to be a valuable technique for evaluating drugs that influence angiogenesis.

 Keywords: magnetic resonance imaging; rheumatoid arthritis; synovitis; vascularity PMID:9640130

  10. Relaxometric studies of gadolinium-functionalized perfluorocarbon nanoparticles for MR imaging.

    PubMed

    de Vries, Anke; Moonen, Rik; Yildirim, Muhammed; Langereis, Sander; Lamerichs, Rolf; Pikkemaat, Jeroen A; Baroni, Simona; Terreno, Enzo; Nicolay, Klaas; Strijkers, Gustav J; Grüll, Holger

    2014-01-01

    Fluorine MRI ((19) F MRI) is receiving an increasing attention as a viable alternative to proton-based MRI ((1) H MRI) for dedicated application in molecular imaging. The (19) F nucleus has a high gyromagnetic ratio, a 100% natural abundance and is furthermore hardly present in human tissues allowing for hot spot MR imaging. The applicability of (19) F MRI as a molecular and cellular imaging technique has been exploited, ranging from cell tracking to detection and imaging of tumors in preclinical studies. In addition to applications, developing new contrast materials with improved relaxation properties has also been a core research topic in the field, since the inherently low longitudinal relaxation rates of perfluorocarbon compounds result in relatively low imaging efficiency. Borrowed from (1) H MRI, the incorporation of lanthanides, specifically Gd(III) complexes, as signal modulating ingredients in the nanoparticle formulation has emerged as a promising approach to improvement of the fluorine signal. Three different perfluorocarbon emulsions were investigated at five different magnetic field strengths. Perfluoro-15-crown-5-ether was used as the core material and Gd(III)DOTA-DSPE, Gd(III)DOTA-C6-DSPE and Gd(III)DTPA-BSA as the relaxation altering components. While Gd(III)DOTA-DSPE and Gd(III)DOTA-C6-DSPE were favorable constructs for (1) H NMR, Gd(III)DTPA-BSA showed the strongest increase in (19F) R(1). These results show the potential of the use of paramagnetic lipids to increase (19F) R(1) at clinical field strengths (1.5-3 T). At higher field strengths (6.3-14 T), gadolinium does not lead to an increase in (19F) R(1) compared with emulsions without gadolinium, but leads to an significant increase in (19F) R(2). Our data therefore suggest that the most favorable situation for fluorine measurements is at high magnetic fields without the inclusion of gadolinium constructs.

  11. Sunscreening Agents

    PubMed Central

    Martis, Jacintha; Shobha, V; Sham Shinde, Rutuja; Bangera, Sudhakar; Krishnankutty, Binny; Bellary, Shantala; Varughese, Sunoj; Rao, Prabhakar; Naveen Kumar, B.R.

    2013-01-01

    The increasing incidence of skin cancers and photodamaging effects caused by ultraviolet radiation has increased the use of sunscreening agents, which have shown beneficial effects in reducing the symptoms and reoccurrence of these problems. Many sunscreen compounds are in use, but their safety and efficacy are still in question. Efficacy is measured through indices, such as sun protection factor, persistent pigment darkening protection factor, and COLIPA guidelines. The United States Food and Drug Administration and European Union have incorporated changes in their guidelines to help consumers select products based on their sun protection factor and protection against ultraviolet radiation, whereas the Indian regulatory agency has not yet issued any special guidance on sunscreening agents, as they are classified under cosmetics. In this article, the authors discuss the pharmacological actions of sunscreening agents as well as the available formulations, their benefits, possible health hazards, safety, challenges, and proper application technique. New technologies and scope for the development of sunscreening agents are also discussed as well as the role of the physician in patient education about the use of these agents. PMID:23320122

  12. Caustic Precipitation of Plutonium Using Gadolinium as the Neutron Poison for Disposition to High Level Waste

    SciTech Connect

    Bronikowski, M.G.

    2002-06-24

    Nuclear Materials Management Division (NMMD) has proposed that up to 100 kg of the plutonium (Pu) solutions stored in H-Canyon be precipitated with a nuclear poison and dispositioned to H-Area Tank Farm. The use of gadolinium (Gd) as the poison would greatly reduce the number of additional glass logs resulting from this disposition. This report summarizes the characteristics of the precipitation process and addresses criticality concerns in the Nuclear Criticality Safety Evaluation. No problems were found with the nature of the precipitate or the neutralization process.

  13. Controlled manipulation of gadolinium-coordinated supramolecules by low-temperature scanning tunneling microscopy.

    PubMed

    Urgel, José I; Ecija, David; Auwärter, Willi; Barth, Johannes V

    2014-03-12

    Coordination bonding between para-quarterphenyl-dicarbonitrile linkers and gadolinium on Ag(111) has been exploited to construct pentameric mononuclear supramolecules, consisting of a rare-earth center surrounded by five molecular linkers. By employing a scanning tunneling microscope tip, a manipulation protocol was developed to position individual pentamers on the surface. In addition, the tip was used to extract and replace individual linkers yielding tetrameric, pentameric, nonameric, and dodecameric metallosupramolecular arrangements. These results open new avenues toward advanced nanofabrication methods and rare-earth nanochemistry by combining the versatility of metal-ligand interactions and atomistic manipulation capabilities.

  14. Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

    SciTech Connect

    Ostafiychuk, B. K.; Yaremiy, I. P. Yaremiy, S. I.; Fedoriv, V. D.; Tomyn, U. O.; Umantsiv, M. M.; Fodchuk, I. M.; Kladko, V. P.

    2013-12-15

    The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

  15. Safety Evaluation and Imaging Properties of Gadolinium-Based Nanoparticles in nonhuman primates

    PubMed Central

    Kotb, Shady; Piraquive, Joao; Lamberton, Franck; Lux, François; Verset, Michael; Di Cataldo, Vanessa; Contamin, Hugues; Tillement, Olivier; Canet-Soulas, Emmanuelle; Sancey, Lucie

    2016-01-01

    In this article, we report the safety evaluation of gadolinium-based nanoparticles in nonhuman primates (NHP) in the context of magnetic resonance imaging (MRI) studies in atherosclerosis bearing animals and healthy controls. In healthy NHP, the pharmacokinetics and toxicity profiles demonstrated the absence of dose, time, and sex-effects, as well as a suitable tolerance of intravenous administration of the nanoparticles. We investigated their imaging properties for arterial plaque imaging in a standard diet or a high cholesterol diet NHP, and compared their characteristics with clinically applied Gd-chelate. This preliminary investigation reports the efficient and safe imaging of atherosclerotic plaques. PMID:27725693

  16. Gadolinium(III)-sensitized fluorescence of europium in its mixed-metal compounds with trifluroacetate

    NASA Astrophysics Data System (ADS)

    Kalinovskaya, I. V.; Zadorozhnaya, A. N.

    2017-04-01

    The fluorescence properties of mixed-metal compounds of Eu(III) and Gd(III) with trifluoroacetic acid, Eu1-xGdx(C2F3O2)3·yD·zH2O, where D - 1,10-phenanthroline, 2,2-dipyridil, diphenylguanidine, x = 0, 0.25, 0.5, or 0.7, were studied. Luminescence spectroscopic evidence and the examination of excitation spectra indicate the occurrence of efficient energy transfer from the gadolinium to the europium ion. The greatest promotion of Eu3+ photoluminescence at 615 nm is observed when Eu:Gd = 1:1.

  17. Core-shell monodisperse spherical mSiO2/Gd2O3:Eu3+@mSiO2 particles as potential multifunctional theranostic agents

    NASA Astrophysics Data System (ADS)

    Eurov, Daniil A.; Kurdyukov, Dmitry A.; Kirilenko, Demid A.; Kukushkina, Julia A.; Nashchekin, Alexei V.; Smirnov, Alexander N.; Golubev, Valery G.

    2015-02-01

    Core-shell nanoparticles with diameters in the range 100-500 nm have been synthesized as monodisperse spherical mesoporous (pore diameter 3 nm) silica particles with size deviation of less than 4 %, filled with gadolinium and europium oxides and coated with a mesoporous silica shell. It is shown that the melt technique developed for filling with gadolinium and europium oxides provides a nearly maximum filling of mesopores in a single-run impregnation, with gadolinium and europium uniformly distributed within the particles and forming no bulk oxides on their surface. The coating with a shell does not impair the monodispersity and causes no coagulation. The coating technique enables controlled variation of the shell thickness within the range 5-100 % relative to the core diameter. The thus produced nanoparticles are easily dispersed in water, have large specific surface area (300 m2 g-1) and pore volume (0.3 cm3 g-1), and are bright solid phosphor with superior stability in aqueous media. The core-shell structured particles can be potentially used for cancer treatment as a therapeutic agent (gadolinium neutron-capture therapy and drug delivery system) and, simultaneously, as a multimodal diagnostic tool (fluorescence and magnetic resonance imaging), thereby serving as a multifunctional theranostic agent.

  18. Multi-Agent Information Classification Using Dynamic Acquaintance Lists.

    ERIC Educational Resources Information Center

    Mukhopadhyay, Snehasis; Peng, Shengquan; Raje, Rajeev; Palakal, Mathew; Mostafa, Javed

    2003-01-01

    Discussion of automated information services focuses on information classification and collaborative agents, i.e. intelligent computer programs. Highlights include multi-agent systems; distributed artificial intelligence; thesauri; document representation and classification; agent modeling; acquaintances, or remote agents discovered through…

  19. Single crystal Processing and magnetic properties of gadolinium nickel

    SciTech Connect

    Shreve, Andrew John

    2012-01-01

    GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd2O3 W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.

  20. Effect of solid-phase amorphization on the spectral characteristics of europium-doped gadolinium molybdate

    NASA Astrophysics Data System (ADS)

    Shmurak, S. Z.; Kiselev, A. P.; Kurmasheva, D. M.; Red'Kin, B. S.; Sinitsyn, V. V.

    2010-05-01

    A method is proposed for detecting spectral characteristics of optically inactive molybdates of rare-earth elements by their doping with rare-earth ions whose luminescence lies in the transparency region of all structural modifications of the sample. Gadolinium molybdate is chosen as the object of investigations, while europium ions are used as an optically active and structurally sensitive admixture. It is shown that after the action of a high pressure under which gadolinium molybdate passes to the amorphous state, the spectral characteristics of Gd1.99Eu0.01(MoO4)3 (GMO:Eu) change radically; namely, considerable line broadening is observed in the luminescence spectra and the luminescence excitation spectra, while the long-wave threshold of optical absorption is shifted considerably (by approximately 1.1 eV) towards lower energies. It is found that by changing the structural state of GMO:Eu by solid-state amorphization followed by annealing, the spectral characteristics of the sample can be purposefully changed. This is extremely important for solving the urgent problem of designing high-efficiency light-emitting diodes producing “white” light.

  1. Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal

    PubMed Central

    Frietsch, B.; Bowlan, J.; Carley, R.; Teichmann, M.; Wienholdt, S.; Hinzke, D.; Nowak, U.; Carva, K.; Oppeneer, P. M.; Weinelt, M.

    2015-01-01

    The Heisenberg–Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale. PMID:26355196

  2. Thermal neutron capture cross section of gadolinium by pile-oscillation measurements in MINERVE

    SciTech Connect

    Leconte, P.; Di-Salvo, J.; Antony, M.; Pepino, A.; Hentati, A.

    2012-07-01

    Natural gadolinium is used as a burnable poison in most LWR to account for the excess of reactivity of fresh fuels. For an accurate prediction of the cycle length, its nuclear data and especially its neutron capture cross section needs to be known with a high precision. Recent microscopic measurements at Rensselaer Polytechnic Inst. (RPI) suggest a 11% smaller value for the thermal capture cross section of {sup 157}Gd, compared with most of evaluated nuclear data libraries. To solve this inconsistency, we have analyzed several pile-oscillation experiments, performed in the MINERVE reactor. They consist in the measurement of the reactivity variation involved by the introduction in the reactor of small-samples, containing different mass amounts of natural gadolinium. The analysis of these experiments is done through the exact perturbation theory, using the PIMS calculation tool, in order to link the reactivity effect to the thermal capture cross section. The measurement of reactivity effects is used to deduce the 2200 m.s-1 capture cross section of {sup nat}Gd which is (49360 {+-} 790) b. This result is in good agreement with the JEFF3.1.1 value (48630 b), within 1.6% uncertainty at 1{sigma}, but is strongly inconsistent with the microscopic measurements at RPI which give (44200 {+-} 500) b. (authors)

  3. Density functional calculations for structural, electronic, and magnetic properties of gadolinium-oxide clusters

    SciTech Connect

    Yuan, H. K.; Chen, H. Tian, C. L.; Kuang, A. L.; Wang, J. Z.

    2014-04-21

    Gadolinium-oxide clusters in various sizes and stoichiometries have been systematically studied by employing the density functional theory with the generalized gradient approximation. The clusters in bulk stoichiometry are relatively more stable and their binding energies increase with the increasing size. Stoichiometric (Gd{sub 2}O{sub 3}){sub n} clusters of n = 1–3 prefer cage-like structures, whereas the clusters of n = 4–30 prefer compact structures layered by wedge-like units and exhibit a rough feature toward the bulk-like arrangement with small disorders of atomic positions. The polyhedral-cages analogous to carbon-fullerenes are stable isomers yet not the minimum energy configurations. Their stabilities can be improved by embedding one oxygen atom or a suitable cage to form core-shell configurations. The mostly favored antiferromagnetic couplings between adjacent Gd atoms are nearly degenerated in energy with their ferromagnetic couplings, resulting in super-paramagnetic characters of gadolinium-oxide clusters. The Ruderman-Kittel-Kasuya-Yosida (RKKY)-type mechanism together with the superexchange-type mechanism plays cooperation role for the magnetic interactions in clusters. We present, as a function of n, calculated binding energies, ionization potential, electron affinity, and electronic dipole moment.

  4. Order-disorder transitions in gadolinium zirconate: A potential electrolyte material in solid oxide fuel cells

    SciTech Connect

    Meilicke, S.; Haile, S.

    1995-12-31

    Rare-earth, yttrium, and calcium doped zirconates are the materials of choice for electrolytes in solid oxide fuel cells. The dopant in these materials serves not only to stabilized the cubic phase of zirconia, but also to introduce anion defects that presumably increase the ionic conductivity. In order to understand the relationships between anion defect distribution, thermal history and ionic conductivity, the structural properties of gadolinium zirconate, Gd{sub 2}Zr{sub 2}O{sub 7}, have been examined via high-temperature x-ray powder diffraction. Gadolinium zirconate is an ideal material for such a structure-property-processing study: it shows ordering of defects at low temperatures, taking on a pyrochlore structure, and disordering at elevated temperature, taking on a defect fluorite structure. Diffraction experiments, performed as functions of time and temperature, confirmed the transition temperature to lie between 1,500 and 1,550 C. They also revealed that the transformation takes place most rapidly just below the transition temperature, indicating that the ordering process is kinetically constrained at low temperatures. Moreover, x-ray data collected at room temperature from quenched samples were found to be as useful, if not more so, than those collected in situ at high temperature. The latter are affected by thermal scattering, severely compromising data quality.

  5. Modulation of channel activity and gadolinium block of MscL by static magnetic fields.

    PubMed

    Petrov, Evgeny; Martinac, Boris

    2007-02-01

    The magnetic field of the Earth has for long been known to influence the behaviour and orientation of a variety of living organisms. Experimental studies of the magnetic sense have, however, been impaired by the lack of a plausible cellular and/or molecular mechanism providing meaningful explanation for detection of magnetic fields by these organisms. Recently, mechanosensitive (MS) ion channels have been implied to play a role in magnetoreception. In this study we have investigated the effect of static magnetic fields (SMFs) of moderate intensity on the activity and gadolinium block of MscL, the bacterial MS channel of large conductance, which has served as a model channel to study the basic physical principles of mechanosensory transduction in living cells. In addition to showing that direct application of the magnetic field decreased the activity of the MscL channel, our study demonstrates for the first time that SMFs can reverse the effect of gadolinium, a well-known blocker of MS channels. The results of our study are consistent with a notion that (1) the effects of SMFs on the MscL channels may result from changes in physical properties of the lipid bilayer due to diamagnetic anisotropy of phospholipid molecules and consequently (2) cooperative superdiamagnetism of phospholipid molecules under influence of SMFs could cause displacement of Gd(3+) ions from the membrane bilayer and thus remove the MscL channel block.

  6. Effects of Polyethyleneimine on the Sonochemical Synthesis of Gadolinium Ion-Modified ZnO Nanorods.

    PubMed

    Choi, Seok Cheol; Yun, Won Suk; Sohn, Sang Ho

    2015-01-01

    We prepared gadolinium (Gd) ion-modified ZnO nanorods by a sonochemical decomposition of zinc acetate dehydrate and gadolinium acetate hydrate precursor solutions with and without polyethyleneimine (PEI). We investigated the effects of PEI on the sonochemical synthesis of ZnO nanorods with and without Gd ion modifications. In the case of nascent ZnO nanorods, PEI in the precursor solutions can prohibit radial growth but allow axial growth, resulting in changes in the degree of preferred crystal orientations, and in the PL properties of the resulting nanorods. In the case of Gd ion-modified ZnO nanorods, we observed that the ZnO nanorods, fabricated sonochemically in the precursor solutions with PEI, exhibited a peak broadening of the ZnO(002) crystal plane and decreasing crystal orientation with respect to the c plane. We note that PEI can negatively affect the crystal orientation and crystallinity of Gd ion-modified ZnO nanorods, even though it cannot affect the lattice constant.

  7. Development of a gadolinium-loaded liquid scintillator for the Hanaro short baseline prototype detector

    NASA Astrophysics Data System (ADS)

    Yeo, In Sung; Joo, Kyung Kwang; So, Sun Heang; Song, Sook Hyung; Kim, Hong Joo; So, Jung Ho; Park, Kang Soon; Ma, Kyung Ju; Jeon, Eun Ju; Kim, Jin Yu; Kim, Young Duk; Lee, Jason; Lee, Jeong-Yeon; Sun, Gwang-Min

    2014-02-01

    We propose a new experiment on the site of the Korea Atomic Energy Research Institute (KAERI) located at Daejeon, Korea. The Hanaro short baseline (SBL) nuclear reactor with a thermal power output 30 MW is used to investigate a reactor neutrino anomaly. A Hanaro SBL prototype detector having a 60- l volume has been constructed ˜6 m away from the reactor core. A gadolinium (Gd)-loaded liquid scintillator (LS) is used as an active material to trigger events. The selection of the LS is guided by physical and technical requirements, as well as safety considerations. A linear alkyl benzene (LAB) is used as a base solvent of the Hanaro SBL prototype detector. Three g/ l of PPO and 30 mg/ l of bis-MSB are dissolved to formulate the LAB-based LS. Then, a 0.5% gadolinium (Gd) complex with carboxylic acid is loaded into the LAB-based LS by using the liquidliquid extraction method. In this paper, we will summarize all the characteristics of the Gd-loaded LAB-based LS for the Hanaro prototype detector.

  8. Chemical and magnetic structure of uranium/gadolinium multilayers studied by transmission

    SciTech Connect

    Wilkins, S.B.; Springell, R.; Langridge, S.; Wildes, A.; Sanchez-Hanke, C.; Moore, K.T.; Butterfield, M.; Chivall, J.; Ward, R.C.C.; Wells, M.R.; Lander, G.H.

    2010-04-29

    We present a multitechnique approach to study the detailed chemical and magnetic structure of uranium/gadolinium multilayers. At low temperature the saturation magnetization is found to be {approx}60% of that of bulk gadolinium. We address this problem, which is found in many other multilayers and suggest a model that may have wider applications. Transmission electron microscopy images indicate a microstructure, consistent with a columnar growth of Gd with crystallites of the order 20 {yields} 100{angstrom}. Off-specular neutron scattering is most strongly visible at saturation field, indicating that Gd moments are not aligned with the applied field. X-ray resonant magnetic scattering provides proof of coupled in-plane length scales for both the structural and the magnetic roughness. A detailed x-ray scattering study of both the specular and off-specular reflectivities has been used to investigate the in-plane structure of the multilayers. We calculate the roughness and transverse correlation cut-off length, {zeta}{sub x} = 120 {+-} 30{angstrom}, and present a simple model to determine an average column size of 27 {+-} 6{angstrom} and a reduction in the magnetic saturation of {approx}40%.

  9. Importance of timing of post-contrast MRI in rheumatoid arthritis: what happens during the first 60 minutes after IV gadolinium-DTPA?

    PubMed Central

    Ostergaard, M; Klarlund, M

    2001-01-01

    BACKGROUND—Volumes of inflamed synovial membrane determined by magnetic resonance imaging (MRI) are closely related to histopathological synovitis and may predict erosive progression in rheumatoid arthritis (RA). However, after IV injection, leakage of MRI contrast from the synovium gradually compromises the differentiation of synovium from joint fluid.
OBJECTIVE—To determine the time period after IV MRI contrast (gadolinium-DTPA (Gd)) injection in which synovial membrane volume determination is reliable.
METHODS—MRI of five RA knees with clinical synovitis was carried out, with axial, T1 weighted, spin echo images before IV Gd injection and every 1.75 minutes for 60 minutes post-Gd. By a semiautomated "signal enhancement threshold" method, including voxels with >35% or >45% relative post-Gd enhancement, synovial membrane volumes were estimated at each time point. At 4.25 minutes post-Gd, volumes were also determined by a more accurate but time consuming "manual method".
RESULTS—The initially observed synovium-effusion borderline remained clearly visible, and on the same location, within at least the initial 11 minutes post-Gd (that is, within the normal time frame of post-Gd imaging in RA) but started blurring and moving centripetally thereafter. Compared with volumes at all other time points, synovial membrane volumes at 0.75 and 2.50 minutes post-Gd were significantly lower (Wilcoxon-Pratt), suggesting that some synovial membrane areas had not yet exceeded the enhancement threshold. Thereafter, the measured volumes remained practically unchanged.
CONCLUSION—This study suggests that MR image acquisition in arthritic knee joints should be performed within the initial approximately 10 minutes after gadolinium contrast injection to achieve the most accurate distinction between synovium and joint fluid but that small time variations are not of major importance to the measured synovial membrane volumes.

 PMID:11602477

  10. The determination of samarium, europium, gadolinium and dysprosium in uranium products by direct-current plasma emission spectrometry.

    PubMed

    Flavelle, F; Westland, A D

    1986-05-01

    Samarium, europium, gadolinium and dysprosium were separated from uranium-containing materials by means of solvent extraction with Alamine 336, followed by cation-exchange. The elements were determined in the sub-ppm range by means of direct-current plasma atomic-emission spectrometry.

  11. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

    SciTech Connect

    Hoffman, R D; Kelley, K; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).

  12. Topical hemostatic agents for dermatologic surgery.

    PubMed

    Larson, P O

    1988-06-01

    Topical hemostatic agents are very helpful in attaining capillary and small vessel hemostasis in dermatologic surgery. The commonly used topical hemostatic agents, including oxidized cellulose, absorbable gelatin, and thrombin are reviewed, along with newer agents such as microfibrillar collagen, fibrin sealants, and acrylates. Agents best suited for certain situations are recommended.

  13. Gadolinium oxide nanoparticles and aptamer-functionalized silver nanoclusters-based multimodal molecular imaging nanoprobe for optical/magnetic resonance cancer cell imaging.

    PubMed

    Li, Jingjing; You, Jia; Dai, Yue; Shi, Meilin; Han, Cuiping; Xu, Kai

    2014-11-18

    Multimodal molecular imaging has attracted more and more interest from researchers due to its combination of the strengths of each imaging modality. The development of specific and multifunctional molecular imaging probes is the key for this method. In this study, we fabricated an optical/magnetic resonance (MR) dual-modality molecular imaging nanoprobe, polyethylene glycol-coated ultrasmall gadolinium oxide (PEG-Gd2O3)/aptamer-Ag nanoclusters (NCs), for tracking cancer cells. To achieve this aim, PEG-Gd2O3 nanoparticles (NPs) as magnetic resonance imaging (MRI) contrast agent and aptamer functionalized silver nanoclusters (aptamer-Ag NCs) as fluorescence reporter were first synthesized by a one-pot approach, respectively. They were then conjugated by the covalent coupling reaction between the carboxyl group on the surface of PEG-Gd2O3 NPs and amino group modified on the 5'-end of AS1411 aptamer. With a suitable ratio, the fluorescence intensity of aptamer-Ag NCs and MR signal of PEG-Gd2O3 nanoparticles could both be enhanced after the formation of PEG-Gd2O3/aptamer-Ag NCs nanoprobe, which favored their application for multimodal molecular imaging. With this nanoprobe, MCF-7 tumor cells could be specifically tracked by both fluorescence imaging and magnetic resonance imaging in vitro.

  14. In Vivo Tracking of Phagocytic Immune Cells Using a Dual Imaging Probe with Gadolinium-Enhanced MRI and Near-Infrared Fluorescence.

    PubMed

    Kim, Eun-Joong; Bhuniya, Sankarprasad; Lee, Hyunseung; Kim, Hyun Min; Shin, Weon Sup; Kim, Jong Seung; Hong, Kwan Soo

    2016-04-27

    A novel dual imaging probe for in vivo magnetic resonance imaging (MRI) and optical imaging was developed by combining gadolinium (Gd)-chelating MR probe and a near-infrared (NIR) fluorophore, aza-BODIPY (AB; BODIPY = boron-dipyrromethene). This aza-BODIPY-based bimodal contrast agent (AB-BCA) showed a significant fluorescence emission around the NIR range and an enhanced longitudinal relaxivity in MR modality. The probe was easily delivered to phagocytic cells of the innate immune system, together with macrophages and dendritic cells (DCs), and presented high-performance fluorescence and MR imaging without obvious cytotoxicity. For in vivo visualization of AB-BCA using MRI and optical imaging, bone marrow-derived DCs were labeled and injected into the footpad of mice, and labeled DCs were tracked in vivo. We observed the migration of AB-BCA-labeled DCs into the lymph nodes via lymphatic vessels using NIR fluorescence and T1-weighted MR images. This dual-modality imaging probe was used for noninvasive monitoring of DC migration into lymph nodes and could be useful for investigating advanced cellular immunotherapy.

  15. Exclusive photothermal heat generation by a gadolinium bis(naphthalocyanine) complex and inclusion into modified high-density lipoprotein nanocarriers for therapeutic applications.

    PubMed

    Mathew, Simon; Murakami, Tatsuya; Nakatsuji, Hirotaka; Okamoto, Haruki; Morone, Nobuhiro; Heuser, John E; Hashida, Mitsuru; Imahori, Hiroshi

    2013-10-22

    A hydrophobic gadolinium bis(naphthalocyanine) sandwich complex (GdSand) possessing several absorbances across visible and infrared wavelengths (up to 2500 nm) was solubilized in aqueous solution by uptake into a nascent mutant high-density lipoprotein (HDL) nanocarrier. The HDL nanocarrier was additionally functionalized with a trans-activator of transcription peptide sequence to promote efficient cell penetration of the drug delivery system (cpHDL). The dye-loaded nanocarrier (GdSand@cpHDL) exhibited photothermal heat generation properties upon irradiation with near-infrared (NIR) laser light, with controllable heat generation abilities as a function of the incident laser light power. Comparison of the photothermal behavior of the dyes GdSand and the well-explored molecular photothermal agent indocyanine green (ICG) in the cpHDL nanocarrier (i.e., ICG@cpHDL) revealed two significant advantages of GdSand@cpHDL: (1) the ability to maintain elevated temperatures upon light absorption for extended periods of time, with a reduced degree of self-destruction of the dye, and (2) exclusive photothermal heat generation with no detectable singlet oxygen production leading to improved integrity of the cpHDL nanocarrier after irradiation. Finally, GdSand@cpHDL was successfully subjected to an in vitro study against NCI-H460 human lung cancer cells, demonstrating the proof-of-principle utility of lanthanide sandwich complexes in photothermal therapeutic applications.

  16. The application of Anthropogenic Gadolinium as a tracer in ground and surface water: examples from France and the Netherlands

    NASA Astrophysics Data System (ADS)

    Klaver, G.; Verheul, M.; Petelet-Giraud, E.; Negrel, P. J.

    2011-12-01

    Gadolinium chelates have been used since 1988 as contrasts agents in medical imaging (MRI) and produce positive anthropogenic Gd anomalies in rare element shale normalized patterns (REEnasc) of river and lake waters. Both in the Netherlands and France the presence of a positive Gd anomaly in surface and groundwater is used as a common tool in complex surface-surface and surface-groundwater studies. In this poster 3 examples of this common practice are given. The "Ile du Chambon" catchment (100 ha) is located in the Allier Valley, within Oligocene alluvial formations (sand and gravel). The nitrate content in the wells of the drinking water supply is ≥ 50 mg/l and two sources for the origin of the nitrates are hypothesized: agriculture or wastewater from a waste water treatment plant. Widory et al. (2005), using a coupled chemical (Cl and NO3) and isotopic (nitrogen and boron) approach, could show that the wastewater was the main source of the nitrate pollution. The presence of a Gd anomaly in the shale normalized rare earth patterns of wells contaminated by the waste water confirms the findings of Widory et al. (2005). In the second case the Gd anomaly is used to follow the infiltration of river water into a small lake in the Netherlands. During dry periods in this small river, Meuse water with a distinct Gd anomaly is fed into this river. The REE were monitored in the river, in a piezometer installed in the dike between the river and the lake and in the lake before, during and after the Meuse water was fed into this river. With the time series analyses the infiltration of the Meuse water into the dike and the small lake could be clearly followed. In a third case, in the center of the Netherlands, the flow of inlet Meuse water with a distinct Gd anomaly into a polder and subsequently from the larger into the smaller ditches of this polder were followed by analyzing the REEs. In such dry periods the ditches in the polder are also fed by groundwater that does not

  17. Tolerance and Long-Term MRI Imaging of Gadolinium-Modified Meshes Used in Soft Organ Repair

    PubMed Central

    Letouzey, Vincent; Huberlant, Stéphanie; Cornille, Arnaud; Blanquer, Sébastien; Guillaume, Olivier; Lemaire, Laurent; Garric, Xavier; de Tayrac, Renaud

    2015-01-01

    Background Synthetic meshes are frequently used to reinforce soft tissues. The aim of this translational study is to evaluate tolerance and long-term MRI visibility of two recently developed Gadolinium-modified meshes in a rat animal model. Materials and Methods Gadolinium-poly-ε-caprolactone (Gd-PCL) and Gadolinium-polymethylacrylate (Gd-PMA) modified meshes were implanted in Wistar rats and their tolerance was assessed daily. Inflammation and biocompatibility of the implants were assessed by histology and immunohistochemistry after 30 days post implantation. Implants were visualised by 7T and 3T MRI at day 30 and at day 90. Diffusion of Gadolinium in the tissues of the implanted animals was assessed by Inductively Coupled Plasma Mass Spectrometry. Results Overall Gd-PMA coated implants were better tolerated as compared to those coated with Gd-PCL. In fact, Gd-PMA implants were characterised by a high ratio collagen I/III and good vascularisation of the integration tissues. High resolution images of the coated mesh were obtained in vivo with experimental 7T as well as 3T clinical MRI. Mass spectrometry analyses showed that levels of Gadolinium in animals implanted with coated mesh were similar to those of the control group. Conclusions Meshes coated with Gd-PMA are better tolerated as compared to those coated with Gd-PCL as no signs of erosion or significant inflammation were detected at 30 days post implantation. Also, Gd-PMA coated meshes were clearly visualised with both 7T and 3T MRI devices. This new technique of mesh optimisation may represent a valuable tool in soft tissue repair and management. PMID:25811855

  18. Effect of gadolinium on the ryanodine receptor/sarcoplasmic reticulum calcium release channel of skeletal muscle.

    PubMed

    Sárközi, Sándor; Szegedi, Csaba; Lukács, Balázs; Ronjat, Michel; Jóna, István

    2005-01-01

    The effect of gadolinium ions on the sarcoplasmic reticulum (SR) calcium release channel/ryanodine receptor (RyR1) was studied using heavy SR (HSR) vesicles and RyR1 isolated from rabbit fast twitch muscle. In the [(3)H]ryanodine binding assay, 5 microM Gd(3+) increased the K(d) of the [(3)H]ryanodine binding of the vesicles from 33.8 nM to 45.6 nM while B(max), referring to the binding capacity, was not affected significantly. In the presence of 18 nM[(3)H]ryanodine and 100 microM free Ca(2+), Gd(3+) inhibited the binding of the radiolabeled ryanodine with an apparent K(d) value of 14.7 microM and a Hill coefficient of 3.17. In (45)Ca(2+) experiments the time constant of (45)Ca(2+) efflux from HSR vesicles increased from 90.9 (+/- 11.1) ms to 187.7 (+/- 24.9) ms in the presence of 20 microM gadolinium. In single channel experiments gadolinium inhibited the channel activity from both the cytoplasmic (cis) (IC(50) = 5.65 +/- 0.33 microM, n(Hill) = 4.71) and the luminal (trans) side (IC(50) = 5.47 +/- 0.24 microM, n(Hill) = 4.31). The degree of inhibition on the cis side didn't show calcium dependency in the 100 microM to 1 mM Ca(2+) concentration range which indicates no competition with calcium on its regulatory binding sites. When Gd(3+) was applied at the trans side, EGTA was present at the cis side to prevent the binding of Gd(+3) to the cytoplasmic calcium binding regulatory sites of the RyR1 if Gd(3+) accidentally passed through the channel. The inhibition of the channel did not show any voltage dependence, which would be the case if Gd(3+) exerted its effect after getting to the cis side. Our results suggest the presence of inhibitory binding sites for Gd(3+) on both sides of the RyR1 with similar Hill coefficients and IC(50) values.

  19. Results of the Phase I Dose-Escalating Study of Motexafin Gadolinium With Standard Radiotherapy in Patients With Glioblastoma Multiforme

    SciTech Connect

    Ford, Judith M. Seiferheld, Wendy; Alger, Jeffrey R.; Wu, Genevieve; Endicott, Thyra J.; Mehta, Minesh; Curran, Walter; Phan, See-Chun

    2007-11-01

    Purpose: Motexafin gadolinium (MGd) is a putative radiation enhancer initially evaluated in patients with brain metastases. This Phase I trial studied the safety and tolerability of a 2-6-week course (10-22 doses) of MGd with radiotherapy for glioblastoma multiforme. Methods and Materials: A total of 33 glioblastoma multiforme patients received one of seven MGd regimens starting at 10 doses of 4 mg/kg/d MGd and escalating to 22 doses of 5.3 mg/kg/d MGd (5 or 10 daily doses then three times per week). The National Cancer Institute Cancer Therapy Evaluation Program toxicity and stopping rules were applied. Results: The maximal tolerated dose was 5.0 mg/kg/d MGd (5 d/wk for 2 weeks, then three times per week) for 22 doses. The dose-limiting toxicity was reversible transaminase elevation. Adverse reactions included rash/pruritus (45%), chills/fever (30%), and self-limiting vesiculobullous rash of the thumb and fingers (42%). The median survival of 17.6 months prompted a case-matched analysis. In the case-matched analysis, the MGd patients had a median survival of 16.1 months (n = 31) compared with the matched Radiation Therapy Oncology Group database patients with a median survival of 11.8 months (hazard ratio, 0.43; 95% confidence interval, 0.20-0.94). Conclusion: The maximal tolerated dose of MGd with radiotherapy for glioblastoma multiforme in this study was 5 mg/kg/d for 22 doses (daily for 2 weeks, then three times weekly). The baseline survival calculations suggest progression to Phase II trials is appropriate, with the addition of MGd to radiotherapy with concurrent and adjuvant temozolomide.

  20. KGB agents

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    A short story is reported in which the activity of Communist Party of the USSR and secret KGB agents, which were payed by the State, in view of controlling of the conscience of population. The story reffers to the Physics Department of the Moscow University, Planing Institute of the Gosplan of Moldavian S.S.R. and Chishinau Technical University (actually: Technical University of Moldova), where the author has worked during Soviet times. Almost every 6-th citizen in the USSR was engaged in this activity, while actually the former communists rule in the Republic of Moldova.

  1. Analysis of Blood Gadolinium in an Isotope Geochemist Following Contrast MRI

    NASA Astrophysics Data System (ADS)

    Wasylenki, L. E.

    2011-12-01

    Normal brain tissue does not have blood flowing throughout it; instead oxygen diffuses across a blood-brain barrier in order to oxygenate brain cells. Brain tumors, however, do grow blood supplies, so an abnormal distribution of blood in the brain is a key indicator of abnormal cell growth. But how is the distribution of blood in inside the brain observed? The lanthanide ion gadolinium(III) has unpaired 5f-shell electrons and is thus paramagnetic. As such, the presence of Gd causes the nuclei of nearby atoms to relax more quickly when excited to high-energy spin states by pulses of radio-frequency energy than they would without Gd nearby. The signal in magnetic resonance imaging correlates with this nuclear spin relaxation time, so gadolinium's presence in certain body tissues makes those tissues appear as bright areas on MRI images. Gadolinium is therefore commonly injected intravenously just prior to MRI imaging, so that the distribution of blood in and around the brain can be mapped. Gadolinium as a free ion is toxic, so it is injected in a relatively inert form, often as gadoversetamide, in which Gd is tightly bound in nine-fold coordination with N, C, and O. This compound is removed from the blood by the kidneys at a rate that is fast compared to the rate of breakdown of this compound in the blood, thus preventing release of toxic Gd in the bloodstream. But how quickly can the kidneys of an isotope geochemist remove Gd from blood? In this experiment, a single isotope geochemist's wristwatch was synchronized with that of the MRI technician and then left in a dressing room with all other magnetically susceptible objects until after the MRI. The time of intravenous injection of gadoversetamide into the isotopist was recorded by the technician and later transmitted verbally to the isotopist. Following the MRI session, blood samples were collected by self-fingerprick, in a Class 100 trace metal clean lab, from 47 to 281 minutes after intravenous injection. For each

  2. Controllable Fabrication and Optical Properties of Uniform Gadolinium Oxysulfate Hollow Spheres

    PubMed Central

    Chen, Fashen; Chen, Gen; Liu, Tao; Zhang, Ning; Liu, Xiaohe; Luo, Hongmei; Li, Junhui; Chen, Limiao; Ma, Renzhi; Qiu, Guanzhou

    2015-01-01

    Uniform gadolinium oxysulfate (Gd2O2SO4) hollow spheres were successfully fabricated by calcination of corresponding Gd-organic precursor obtained via a facile hydrothermal process. The Gd2O2SO4 hollow spheres have a mean diameter of approximately 550 nm and shell thickness in the range of 30–70 nm. The sizes and morphologies of as-prepared Gd2O2SO4 hollow spheres could be deliberately controlled by adjusting the experimental parameters. Eu-doped Gd2O2SO4 hollow spheres have also been prepared for the property modification and practical applications. The structure, morphology, and properties of as-prepared products were characterized by XRD, TEM, HRTEM, SEM and fluorescence spectrophotometer. Excited with ultraviolet (UV) pump laser, successful downconversion (DC) could be achieved for Eu-doped Gd2O2SO4 hollow spheres. PMID:26671661

  3. Synthesis of bulk-size transparent gadolinium oxide–polymer nanocomposites for gamma ray spectroscopy

    PubMed Central

    Cai, Wen; Chen, Qi; Cherepy, Nerine; Dooraghi, Alex; Kishpaugh, David; Chatziioannou, Arion; Payne, Stephen; Xiang, Weidong

    2015-01-01

    Heavy element loaded polymer composites have long been proposed to detect high energy X- and γ-rays upon scintillation. The previously reported bulk composite scintillators have achieved limited success because of the diminished light output resulting from fluorescence quenching and opacity. We demonstrate the synthesis of a transparent nanocomposite comprising gadolinium oxide nanocrystals uniformly dispersed in bulk-size samples at a high loading content. The strategy to avoid luminescence quenching and opacity in the nanocomposite was successfully deployed, which led to the radioluminescence light yield of up to 27 000/MeV, about twice as much as standard commercial plastic scintillators. Nanocomposites monoliths (14 mm diameter by 3 mm thickness) with 31 wt% loading of nanocrystals generated a photoelectric peak for Cs-137 gamma (662 keV) with 11.4% energy resolution. PMID:26478816

  4. Transient band structures in the ultrafast demagnetization of ferromagnetic gadolinium and terbium

    NASA Astrophysics Data System (ADS)

    Teichmann, Martin; Frietsch, Björn; Döbrich, Kristian; Carley, Robert; Weinelt, Martin

    2015-01-01

    We compare the laser-driven demagnetization dynamics of the rare earths gadolinium and terbium by mapping their transient valance band structures with time- and angle-resolved photoelectron spectroscopy. In both metals, the minority and majority spin valence bands evolve independently with different time constants after optical excitation. The ultrafast shift of the partially unoccupied minority spin bulk band to higher binding energy and of the majority spin surface state to lower binding energy suggests spin transport between surface and bulk. The slower response of the fully occupied majority spin band follows the lattice temperature and is attributed to Elliott-Yafet type spin-flip scattering. Terbium shows a stronger and faster decay of the exchange splitting, pointing to ultrafast magnon emission via 4 f spin-to-lattice coupling.

  5. Obtaining gadolinium nanoparticles and studying their properties in a helium flow

    NASA Astrophysics Data System (ADS)

    Petinov, V. I.

    2016-07-01

    A method for obtaining Gd nanoparticles with diameters of 89 to 18 nm upon metal evaporation both in a flow of pure helium and with the addition of 0.5% of oxygen is described. It is found that the addition of O2 does not affect the size of the particles, their structure, or the Curie temperature, though the magnetization is reduced. Particles with sizes of 18 nm have cubic lattice symmetry (fcc) and remain paramagnetic below T c; with an increase in the size of nanoparticles, the proportion of the hexagonal (hcp) phase, which coincides with the gadolinium structure, also grows, and below T c such particles become ferromagnetic. Oxygen impurities seem to have no effect on magnetic and structural transitions in nanoparticles.

  6. X-ray Absorption Improvement of Single Wall Carbon Nanotube through Gadolinium Encapsulation

    NASA Astrophysics Data System (ADS)

    Alimin; Narsito, I.; Kartini; Santosa, S. J.

    2016-02-01

    X-ray absorption improvement of single-wall carbon nanotube (SWCNT) through gadolinium (Gd) encapsulation has been studied. The liquid phase adsorption using ethanol has been performed for the doping treatment. The Gd-doped SWCNT (Gd@SWCNT) was characterized by nitrogen adsorption isotherms, Raman spectroscopy, Transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) techniques. A relatively high residual weight of Gd@SWCNT compared to non-doped SWCNT (n-SWCNT) indicated that Gd has been doped in the nanotube. Even though Gd nanoparticles could not be observed clearly by TEM image, however, a significant decrease of nitrogen uptakes at low pressure and RBM (Radial Breathing Mode) upshift of Raman spectra of Gd@SWCNT specimen suggest that the metal nanoparticles might be encapsulated in the internal tube spaces of the nanotube. It was found that Gd-doped in the SWCNT increased significantly mass attenuation coefficient of the nanotube.

  7. Effect of Gadolinium Doping on the Air Oxidation of Uranium Dioxide

    SciTech Connect

    Scheele, Randall D.; Hanson, Brady D.; Cumblidge, Stephen E.; Jenson, Evan D.; Kozelisky, Anne E.; Sell, Rachel L.; MacFarlan, Paul J.; Snow, Lanee A.

    2004-12-04

    Researchers at the Pacific Northwest National Laboratory (PNNL) investigated the effects of gadolinia concentration on the air oxidization of gadolinia-doped uranium dioxide using thermogravimetry and differential scanning calorimetry to determine if such doping could improve uranium dioxide's stability as a nuclear fuel during potential accident scenarios in a nuclear reactor or during long-term disposal. We undertook this study to determine whether the resistance of the uranium dioxide to oxidation to the orthorhombic U3O8 with its attendant crystal expansion could be prevented by addition of gadolinia. Our studies found that gadolinium has little effect on the thermal initiation of the first step of the reported two-step air oxidation of UO2; however, increasing gadolinia content does stabilize the initial tetragonal or cubic product allowing significant oxidation before the second expansive step to U3O8 begins.

  8. Dielectric and conducting behavior of gadolinium-terbium fumarate heptahydrate crystals

    NASA Astrophysics Data System (ADS)

    Shah, M. D.; Want, B.

    2015-07-01

    Gadolinium-terbium fumarate heptahydrate crystals were grown in silica gel by using single gel diffusion technique. The crystals were characterized by different physico-chemical techniques of characterization. Powder X-ray diffraction results showed that the grown material is purely crystalline in nature. Elemental analyses suggested the chemical formula of the compound to be Gd Tb (C4H2O4)3ṡ7H2O. Energy dispersive X-ray analysis confirmed the presence of Gd and Tb in the title compound. The dielectric and conductivity studies of the grown compound were carried as function of frequency of applied field and the temperature. The grown material showed a dielectric anomaly which was correlated with its thermal behavior. The ac conductivity of the material showed Jonscher's power law behavior: σ(ω)=σo+Aωs, with a temperature-dependent power exponent s(<1). The conductivity was found to be a function of temperature and frequency.

  9. Feasibility study of a gadolinium-loaded DIN-based liquid scintillator

    NASA Astrophysics Data System (ADS)

    Song, Sook Hyung; Joo, Kyung Kwang; So, Sun Heang; Yeo, In Sung

    2013-09-01

    DIN (di-isopropylnaphthalene) has a high flashpoint and can be used as a base solvent in liquid scintillators. It reduces safety concerns to humans and the environment. (PPO, 3 g/ ℓ) and (bis-MSB, 30 mg/ ℓ) were dissolved to formulate a DIN-based liquid scintillator (LS). A gadolinium (Gd) complex with carboxylic acid was synthesized using a neutralized chemical reaction. Then, 0.1% Gd was loaded into the LS. This Gd-loaded DIN-based LS using a solvent-solvent extraction method is the first attempt at a LS. In this study, we investigated the physical and the optical properties of this LS, and we will summarize all the characteristics of the Gd-loaded DIN-based LS.

  10. Coherent spin dynamics in a gadolinium-doped CaW O4 crystal

    NASA Astrophysics Data System (ADS)

    Baibekov, E. I.; Gafurov, M. R.; Zverev, D. G.; Kurkin, I. N.; Rodionov, A. A.; Malkin, B. Z.; Barbara, B.

    2017-02-01

    We report the first observation of Rabi oscillations in the spin-7/2 ensemble of trivalent gadolinium ions hosted in CaW O4 single crystal. A number of transitions within the lowest electronic multiplet 8S7 /7 2 2 of G d3 + ion are studied using a combination of continuous-wave and pulsed electron paramagnetic resonance spectroscopy. The corresponding Rabi damping curves and the spin coherence times are detected at varying strengths of the microwave field. These data are well reproduced by a theoretical model which accounts for the intrinsic inhomogeneity of the microwave field within the microwave resonator and the magnetic dipole interactions in the diluted spin ensemble. The results indicate that the studied 8-level ground manifold of G d3 + ion can represent an effective three-qubit quantum system.

  11. Characterization of PAH matrix with monazite stream containing uranium, gadolinium and iron

    NASA Astrophysics Data System (ADS)

    Pal, Sangita; Meena, Sher Singh; Goswami, D.

    2016-05-01

    Uranium (U) gadolinium(Gd) and iron (Fe) containing alkaline waste simulated effluent (relevant to alkaline effluent of monazite ore) has been treated with a novel amphoteric resin viz, Polyamidehydroxamate (PAH) containing amide and hydroxamic acid groups. The resin has been synthesized in an eco-friendly manner by polymerization nad conversion to functional groups characterized by FT-IR spectra and architectural overview by SEM. Coloration of the loaded matrix and de-coloration after extraction of uranium is the special characteristic of the matrix. Effluent streams have been analyzed by ICP-AES, U loaded PAH has been characterized by FT-IR, EXAFS, Gd and Fe by X-ray energy values of EDXRF at 6.053 Kev and 6.405 Kev respectively. The remarkable change has been observed in Mössbauer spectrum of Fe-loaded PAH samples.

  12. Biocompatible and high-performance amino acids-capped MnWO4 nanocasting as a novel non-lanthanide contrast agent for X-ray computed tomography and T1-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Dong, Kai; Liu, Zhen; Liu, Jianhua; Huang, Sa; Li, Zhenhua; Yuan, Qinghai; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    -weighted MR imaging capabilities. As an alternative to T2-weighted MRI and CT dual-modality contrast agents, the nanoprobes can provide a positive contrast signal, which prevents confusion with the dark signals from hemorrhage and blood clots. To the best of our knowledge, this is the first report that a non-lanthanide imaging nanoprobe is applied for CT and T1-weighted MRI simultaneously. Moreover, comparing with gadolinium-based T1-weighted MRI and CT dual-modality contrast agents that were associated with nephrogenic systemic fibrosis (NSF), our contrast agents have superior biocompatibility, which is proved by a detailed study of the pharmacokinetics, biodistribution, and in vivo toxicology. Together with excellent dispersibility, high biocompatibility and superior contrast efficacy, these nanoprobes provide detailed and complementary information from dual-modality imaging over traditional single-mode imaging and bring more opportunities to the new generation of non-lanthanide nanoparticulate-based contrast agents. Electronic supplementary information (ESI) available: TEM images of MnWO4 nanoparticles synthesized at pH = 7, 180 °C pH = 9, 180 °C pH = 6, 200 °C with various amino acid molecules as capped agents, survey XPS spectra, FTIR spectrum of glycine capped MnWO4 nanorods, photos of glycine capped MnWO4 nanorods in various solutions including PBS, DMEM cell medium, and FBS, in vivo coronal view CT images of a rat before and after intravenous injection of iobitridol at different timed intervals, in vivo CT imaging of the rat one month after intravenous injection of MnWO4 nanorods, CT values of the heart, liver, spleen and kidney of a rat before and after intravenous administration of MnWO4 nanorods and iobitridol at different time intervals, hematology analysis and blood biochemical assay. See DOI: 10.1039/c3nr05455a

  13. Agent independent task planning

    NASA Technical Reports Server (NTRS)

    Davis, William S.

    1990-01-01

    Agent-Independent Planning is a technique that allows the construction of activity plans without regard to the agent that will perform them. Once generated, a plan is then validated and translated into instructions for a particular agent, whether a robot, crewmember, or software-based control system. Because Space Station Freedom (SSF) is planned for orbital operations for approximately thirty years, it will almost certainly experience numerous enhancements and upgrades, including upgrades in robotic manipulators. Agent-Independent Planning provides the capability to construct plans for SSF operations, independent of specific robotic systems, by combining techniques of object oriented modeling, nonlinear planning and temporal logic. Since a plan is validated using the physical and functional models of a particular agent, new robotic systems can be developed and integrated with existing operations in a robust manner. This technique also provides the capability to generate plans for crewmembers with varying skill levels, and later apply these same plans to more sophisticated robotic manipulators made available by evolutions in technology.

  14. Gelled Anti-icing Agents

    NASA Technical Reports Server (NTRS)

    Markles, O. F.; Sperber, H. H.

    1983-01-01

    Pectin added to antifreeze/water mixture. Formulations include water with dimethyl sulfoxide (DMSO) as deicer and pectin as gel former. Without gelling agent, deicer runs off vertical surfaces. Without pectin solution will completely evaporate in far less time. Agents developed have wide potential for ice prevention on runways, highways, bridges and sidewalks.

  15. Topical hemostatic agents in otolaryngologic surgery.

    PubMed

    Acar, Baran; Babademez, Mehmet Ali; Karabulut, Hayriye

    2010-01-01

    Topical hemostatic agents are largely used to reduce blood loss during otolaryngologic surgery. These agents play an important role in both keeping the patient's hemodynamic equilibrium and allowing for a better view of the surgical field. These agents can be classified based on their mechanism of action, and include physical or mechanical agents. Most complications of topical hemostatic agents are sustained because of the antigenic reaction of those products. This paper reviews traditional and newer topical hemostatic agents with regard to their chemical properties, their mechanisms of action, and the benefits and complications of topical agents.

  16. Pump apparatus including deconsolidator

    DOEpatents

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  17. Health care agents

    MedlinePlus

    Durable power of attorney for health care; Health care proxy; End-of-life - health care agent; Life support treatment - ... Respirator - health care agent; Ventilator - health care agent; Power of attorney - health care agent; POA - health care ...

  18. Optical modulator including grapene

    DOEpatents

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  19. Helium defectoscopy of cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the impurity disorder region

    NASA Astrophysics Data System (ADS)

    Koromyslov, A. V.; Zhiganov, A. N.; Kovalenko, M. A.; Kupryazhkin, A. Ya.

    2013-12-01

    The concentration of impurity anion vacancies formed upon the dissociation of gadolinium-vacancy complexes has been determined using helium defectoscopy of the cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the temperature range T = 740-1123 K and at saturation pressures ranging from 0.05 to 15 MPa. It has been found that the energy of dissociation of gadoliniumvacancy complexes is E {eff/ D }= 0.26 ± 0.06 eV, and the energy of dissolution of helium in anion vacancies in the impurity disorder region is E P = -0.31 ± 0.09 eV. The proposed mechanism of dissolution has been confirmed by the investigation of the electrical conductivity of the cerium gadolinium ceramics, as well as by the high-speed molecular dynamics simulation of the dissociation of gadolinium-vacancy complexes. It has been assumed that a decrease in the effective dissolution energy in comparison with the results of the previously performed low-temperature investigations is caused by the mutual repulsion of vacancies formed upon the dissociation of gadolinium-vacancy complexes in highly concentrated solutions of gadolinium in CeO2 with increasing temperature.

  20. Transdermal delivery of therapeutic agent

    NASA Technical Reports Server (NTRS)

    Kwiatkowski, Krzysztof C. (Inventor); Hayes, Ryan T. (Inventor); Magnuson, James W. (Inventor); Giletto, Anthony (Inventor)

    2008-01-01

    A device for the transdermal delivery of a therapeutic agent to a biological subject that includes a first electrode comprising a first array of electrically conductive microprojections for providing electrical communication through a skin portion of the subject to a second electrode comprising a second array of electrically conductive microprojections. Additionally, a reservoir for holding the therapeutic agent surrounding the first electrode and a pulse generator for providing an exponential decay pulse between the first and second electrodes may be provided. A method includes the steps of piercing a stratum corneum layer of skin with two arrays of conductive microprojections, encapsulating the therapeutic agent into biocompatible charged carriers, surrounding the conductive microprojections with the therapeutic agent, generating an exponential decay pulse between the two arrays of conductive microprojections to create a non-uniform electrical field and electrokinetically driving the therapeutic agent through the stratum corneum layer of skin.

  1. Detecting agents.

    PubMed Central

    Johnson, Susan C

    2003-01-01

    This paper reviews a recent set of behavioural studies that examine the scope and nature of the representational system underlying theory-of-mind development. Studies with typically developing infants, adults and children with autism all converge on the claim that there is a specialized input system that uses not only morphological cues, but also behavioural cues to categorize novel objects as agents. Evidence is reviewed in which 12- to 15-month-old infants treat certain non-human objects as if they have perceptual/attentional abilities, communicative abilities and goal-directed behaviour. They will follow the attentional orientation of an amorphously shaped novel object if it interacts contingently with them or with another person. They also seem to use a novel object's environmentally directed behaviour to determine its perceptual/attentional orientation and object-oriented goals. Results from adults and children with autism are strikingly similar, despite adults' contradictory beliefs about the objects in question and the failure of children with autism to ultimately develop more advanced theory-of-mind reasoning. The implications for a general theory-of-mind development are discussed. PMID:12689380

  2. Gd-doped BNNTs as T2-weighted MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Ciofani, Gianni; Boni, Adriano; Calucci, Lucia; Forte, Claudia; Gozzi, Alessandro; Mazzolai, Barbara; Mattoli, Virgilio

    2013-08-01

    This work describes, for the first time, doping of boron nitride nanotubes (BNNTs) with gadolinium (Gd@BNNTs), a stable functionalization that permits non-invasive BNNT tracking via magnetic resonance imaging (MRI). We report the structure, Gd loading, and relaxometric properties in water suspension at 7 T of Gd@BNNTs, and show the behaviour of these nanostructures as promising T2-weighted contrast agents. Finally, we demonstrate their complete biocompatibility in vitro on human neuroblastoma cells, together with their ability to effectively label and affect contrast in MRI images at 7 T.

  3. Hydrogels incorporating GdDOTA: towards highly efficient dual T1/T2 MRI contrast agents.

    PubMed

    Courant, Thomas; Roullin, Valérie Gaëlle; Cadiou, Cyril; Callewaert, Maïté; Andry, Marie Christine; Portefaix, Christophe; Hoeffel, Christine; de Goltstein, Marie Christine; Port, Marc; Laurent, Sophie; Elst, Luce Vander; Muller, Robert; Molinari, Michaël; Chuburu, Françoise

    2012-09-03

    Do not tumble dry: Gadolinium-DOTA encapsulated into polysaccharide nanoparticles (GdDOTA NPs) exhibited high relaxivity (r(1) =101.7 s(-1) mM(-1) per Gd(3+) ion at 37 °C and 20 MHz). This high relaxation rate is due to efficient Gd loading, reduced tumbling of the Gd complex, and the hydrogel nature of the nanoparticles. The efficacy of the nanoparticles as a T(1)/T(2) dual-mode contrast agent was studied in C6 cells.

  4. Properties of high k gate dielectric gadolinium oxide deposited on Si (1 0 0) by dual ion beam deposition (DIBD)

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-Ping; Chai, Chun-Lin; Yang, Shao-Yan; Liu, Zhi-Kai; Song, Shu-Lin; Li, Yan-Li; Chen, Nuo-Fu

    2004-09-01

    Gadolinium oxide thin films have been prepared on silicon (1 0 0) substrates with a low-energy dual ion-beam epitaxial technique. Substrate temperature was an important factor to affect the crystal structures and textures in an ion energy range of 100-500 eV. The films had a monoclinic Gd2O3 structure with preferred orientation (4 bar 0 2) at low substrate temperatures. When the substrate temperature was increased, the orientation turned to (2 0 2), and finally, the cubic structure appeared at the substrate temperature of 700 °C, which disagreed with the previous report because of the ion energy. The AES studies found that Gadolinium oxide shared Gd2O3 structures, although there were a lot of oxygen deficiencies in the films, and the XPS results confirmed this. AFM was also used to investigate the surface images of the samples. Finally, the electrical properties were presented.

  5. Dramatic impact of the giant local magnetic fields on spin-dependent recombination processes in gadolinium based garnets

    SciTech Connect

    Romanov, N. G. Tolmachev, D. O.; Gurin, A. S.; Uspenskaya, Yu. A.; Asatryan, H. R.; Badalyan, A. G.; Baranov, P. G.; Wieczorek, H.; Ronda, C.

    2015-06-29

    A giant magnetic field effect on spin-dependent recombination of the radiation-induced defects has been found in cerium doped gadolinium based garnet crystals and ceramics, promising materials for scintillator applications. A sharp and strong increase in the afterglow intensity stimulated by external magnetic field and an evidence of the magnetic field memory have been discovered. The effect was ascribed to huge Gd-induced internal magnetic fields, which suppress the recombination, and cross-relaxation with Gd{sup 3+} ions leading to reorientation of the spins of the electron and hole centers. Thus, the spin system of radiation-induced defects in gadolinium garnet based scintillator materials was shown to accumulate significant energy which can be released in external magnetic fields.

  6. Catechin tuned magnetism of Gd-doped orthovanadate through morphology as T1-T2 MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Vairapperumal, Tamilmani; Saraswathy, Ariya; Ramapurath, Jayasree S.; Kalarical Janardhanan, Sreeram; Balachandran Unni, Nair

    2016-10-01

    Tetragonal (t)-LaVO4 has turned out to be a potential host for luminescent materials. Synthesis of t-LaVO4 till date has been based on chelating effect of EDTA making it not ideal for bioimaging applications. An alternative was proposed by us through the use of catechin. In recent times there is interest for new MRI contrast agents that can through appropriate doping function both as MRI contrast and optical/upconversion materials. It is generally believed that under appropriate doping, t-LaVO4 would be a better upconversion material than monoclinic (m)-LaVO4. Based on these postulations, this work explores the use of gadolinium doped t-LaVO4 as an MRI contrast agent. From literature, gadolinium oxide is a good T1 contrast agent. Through this work, using catechin as a template for the synthesis of Gd doped t-LaVO4, we demonstrate the possible use as a T1 contrast agent. Interestingly, as the catechin concentration changes, morphology changes from nanorods to square nanoplates and spheres. In this process, a switch from T1 to T2 contrast agent was also observed. Under optimal concentration of catechin, with a rod shaped Gd doped t-LaVO4 an r2/r1 value of 21.30 was observed. Similarly, with a spherical shape had an r2/r1 value of 1.48 was observed.

  7. Catechin tuned magnetism of Gd-doped orthovanadate through morphology as T1-T2 MRI contrast agents

    PubMed Central

    Vairapperumal, Tamilmani; Saraswathy, Ariya; Ramapurath, Jayasree S.; Kalarical Janardhanan, Sreeram; Balachandran Unni, Nair

    2016-01-01

    Tetragonal (t)-LaVO4 has turned out to be a potential host for luminescent materials. Synthesis of t-LaVO4 till date has been based on chelating effect of EDTA making it not ideal for bioimaging applications. An alternative was proposed by us through the use of catechin. In recent times there is interest for new MRI contrast agents that can through appropriate doping function both as MRI contrast and optical/upconversion materials. It is generally believed that under appropriate doping, t-LaVO4 would be a better upconversion material than monoclinic (m)-LaVO4. Based on these postulations, this work explores the use of gadolinium doped t-LaVO4 as an MRI contrast agent. From literature, gadolinium oxide is a good T1 contrast agent. Through this work, using catechin as a template for the synthesis of Gd doped t-LaVO4, we demonstrate the possible use as a T1 contrast agent. Interestingly, as the catechin concentration changes, morphology changes from nanorods to square nanoplates and spheres. In this process, a switch from T1 to T2 contrast agent was also observed. Under optimal concentration of catechin, with a rod shaped Gd doped t-LaVO4 an r2/r1 value of 21.30 was observed. Similarly, with a spherical shape had an r2/r1 value of 1.48 was observed. PMID:27752038

  8. Vaporizing Fire Extinguishing Agents

    DTIC Science & Technology

    1950-08-18

    the pro- ject under contract included: Dr. Earl T. McBee, Head, Chemistry Department; Dr. Zara D. Welch, Researbh Supervisor; and Dr’s T. R. Santelli...Aeronautics Authority kxperimental Station, Indianapolis, Indiana, which has supplied test data for inclusion in this report. The Medical Division of the...Development of sources of supply for agent anAL con- tainers. f. Service testing. This report oovers technical phases a, b, and a to 1 April 1950, and

  9. Agents Technology Research

    DTIC Science & Technology

    2010-02-01

    62702F 6. AUTHOR(S) Robert Wright, Jeffrey Hudack, Nathaniel Gemelli, Steven Loscalzo, and Tsu Kong Lue 5d. PROJECT NUMBER 558S 5e. TASK...NAME OF RESPONSIBLE PERSON Robert Wright a. REPORT U b. ABSTRACT U c. THIS PAGE U 19b. TELEPHONE NUMBER (Include area code) N/A...avoided by the other agents removing the incentive to lie or free-load. This phenomenon is termed as the shadow of the future and was shown in Robert

  10. Multiwalled carbon nanotube hybrids as MRI contrast agents.

    PubMed

    Kuźnik, Nikodem; Tomczyk, Mateusz Michał

    2016-01-01

    Magnetic resonance imaging (MRI) is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs), their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories.

  11. Multiwalled carbon nanotube hybrids as MRI contrast agents

    PubMed Central

    Tomczyk, Mateusz Michał

    2016-01-01

    Summary Magnetic resonance imaging (MRI) is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs), their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories. PMID:27547627

  12. Including Jews in Multiculturalism.

    ERIC Educational Resources Information Center

    Langman, Peter F.

    1995-01-01

    Discusses reasons for the lack of attention to Jews as an ethnic minority within multiculturalism both by Jews and non-Jews; why Jews and Jewish issues need to be included; and addresses some of the issues involved in the ethical treatment of Jewish clients. (Author)

  13. Magnetic resonance imaging of cardiac sarcoidosis: an evaluation of the cardiac segments and layers that exhibit late gadolinium enhancement

    PubMed Central

    Komada, Tomohiro; Suzuki, Kojiro; Ishiguchi, Hiroaki; Kawai, Hisashi; Okumura, Takahiro; Hirashiki, Akihiro; Naganawa, Shinji

    2016-01-01

    ABSTRACT Cardiac sarcoidosis (CS) can cause sudden death, which is the leading cause of mortality in patients with sarcoidosis in Japan. However, it is difficult to diagnose CS because of the lack of a sensitive diagnostic method for the condition. Late gadolinium-enhanced cardiac magnetic resonance (MR) imaging demonstrates improved sensitivity for diagnosing CS. Therefore, it is important to know the late gadolinium-enhancement (LGE) characteristics of CS on cardiac MR images in order to diagnose CS accurately. In this study, we investigated the most common sites of LGE on cardiac MR images in CS. Late gadolinium-enhanced MR images of 9 consecutive patients with CS (obtained between August 2009 and July 2015) were reviewed by two radiologists. The distribution of LGE was evaluated using the American Heart Association 17-segment model of the left ventricle. The LGE in each segment was also classified into 4 patterns according to the myocardial layer in which it occurred (the subepicardial, subendocardial, intramural, and transmural layer patterns). All 9 patients exhibited LGE in their left ventricle, and 70 of 153 (46%) myocardial segments were enhanced. All of the patients displayed LGE in the basal septal wall. The patients' LGE layer patterns were as follows: subepicardial: 40% (28/70), intramural: 30% (21/70), subendocardial: 16% (11/70), and transmural: 14% (10/70). The basal septum wall and subepicardial layer often exhibit LGE on cardiac MR images in CS patients. LGE can be observed in other segments and layers in some cases. PMID:28008199

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

    PubMed

    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.

  15. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    DOE PAGES

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; ...

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phasemore » diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K« less

  16. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K

  17. Luminescence properties and electronic structure of Ce{sup 3+}-doped gadolinium aluminum garnet

    SciTech Connect

    Dotsenko, V.P.; Berezovskaya, I.V.; Voloshinovskii, A.S.; Zadneprovski, B.I.; Efryushina, N.P.

    2015-04-15

    Highlights: • The luminescence properties of Ce{sup 3+} ions in (Y, Gd){sub 3}Al{sub 5}O{sub 12} are analyzed. • The Gd{sup 3+} → Y{sup 3+} substitution leads to increasing of Ce{sup 3+} noncubic crystal field splitting parameter. • The excitation spectra for the Ce{sup 3+} emission in GdAG contain bands at 6.67, 7.75, and 9.76 eV. • These features are due to the Ce{sup 3+}-bound exciton formation and O 2p → Al 3s, 3p transitions. • Contributions from Al atoms to the conduction-band density of states are quite essential. - Abstract: Yttrium-gadolinium aluminum garnets (YGdAG) doped with Ce{sup 3+} ions have been prepared by co-precipitation method. The luminescent properties of Ce{sup 3+} ions in Gd{sub 3(1−x)}Ce{sub 3x}Al{sub 5}O{sub 12} (x = 0.01) have been studied upon excitation in the 2–20 eV region. The substitution of Gd{sup 3+} for Y{sup 3+} in the garnet structure results in broadening the emission band and shifting its maximum towards the longer wavelengths. It was found that in addition to the 4f → 5d excitation bands of Ce{sup 3+} ions, the excitation spectra for the Ce{sup 3+} emission contain bands at 6.67, 7.75, and 9.76 eV. These bands are attributed to the Ce{sup 3+}-bound exciton formation and O 2p → Al 3s, 3p transitions, respectively. Although gadolinium states dominate near the bottom of the conduction band of Gd{sub 3}Al{sub 5}O{sub 12}, contributions from Al{sub tetr} and Al{sub oct} atoms to the conduction-band density of states are evaluated as quite essential.

  18. Gadolinium-148 production cross section measurements for 600-and 800-MEV protons.

    SciTech Connect

    Kelley, K. C.; Devlin, M. J.; Pitcher, E. J.; Mashnik, S. G.; Hertel, N. E.

    2004-01-01

    In a series of experiments at LANSCE's WNR facility, {sup 148}Gd production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 {mu}m thin W, Ta, and Au foils and 10 {mu}m thin Al activation foils. Gadolinium spallation yields were determined from these foils using alpha spectroscopy and compared with the LANL codes CEM2k+GEM2 and MCNPX. When heavy metal targets, such as tungsten, are bombarded with protons greater than a few hundred MeV many different nuclides are produced. These nuclides are both stable and radioactive and are created by spallation, proton activation, or secondary reactions with neutrons and other nuclear particles made in the target. These products are distributed somewhat heterogeneously throughout a thick target because of the energy dependence of the cross sections and energy loss of the proton beam within the target. From this standpoint, it is difficult to measure nuclide production cross sections for a given energy proton in a thick target. At the Los Alamos Neutron Science Center (LANSCE) accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research (WNR) facility and 1L target at the Manuel Lujan Jr. Neutron Scattering Center. DOE requires hazard classification analyses to be performed on these targets and places limits on radionuclide inventories in the target as a means of determining the 'nuclear facility' category level. Presently, WNR's Target 4 is a non-nuclear facility while the Lujan 1L target is classified as a Category 3 nuclear facility. Gadolinium-148 is a radionuclide created from the spallation of tungsten and other heavy elements. Allowable isotopic inventories are particularly low for this isotope because it is an alpha-particle emitter with a 75-year half-life. The activity level of {sup 148}Gd is generally low, but it encompasses almost two-thirds of the total inhalation dose burden in an accident

  19. (1) H-NMR relaxometric studies of interaction between apoptosis specific MRI paramagnetic contrast agents and micellar models of apoptotic cells.

    PubMed

    Van Koninckxloo, Aurore; Henoumont, Céline; Laurent, Sophie; Muller, Robert N; Vander Elst, Luce

    2016-07-01

    (1) H-NMR was previously used to analyze the interaction between peptides (E3 and R826) selected by phage display to target apoptotic cells and phospholipidic models of these cells. In order to avoid the use of apoptotic cells and to obtain a fast evaluation of the efficiency of the potential MRI contrast agents obtained by grafting these peptides and their scramble analogs on a paramagnetic gadolinium complex, their proton relaxometric behavior was investigated in the presence of micelles mimicking healthy and apoptotic cells. Their preferential interaction with 1,2-dipalmitoyl-sn-glycero-3-phospho-l-serine micelles mimicking apoptotic cells as compared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine micelles modeling healthy cells was shown by nuclear magnetic relaxation dispersion profiles and the enhancement of the transverse proton relaxation rates at 60 MHz. The association constant values confirm the stronger interaction of the selected conjugated peptides (Ka Gd-PMN-E3(gadolinium 2,2',2'',2'''-[((4-carboxy)pyridine-2,6-diyl)bis(methylenenitrilo)]-tetrakis acetate) grafted with E3 peptide): 2.43 10(4)  m(-1) ; Ka Gd-DTPA-R826(gadolinium ((1-p-isothiocyanatobenzyl)-diethylenetriaminepentaacetate) grafted with R826 peptide): 2.91 10(4)  m(-1) ) as compared with their conjugated scrambles (Ka Gd-PMN-E3sc(gadolinium 2,2',2'',2'''-[((4-carboxy)pyridine-2,6-diyl)bis(methylenenitrilo)]-tetrakis acetate) grafted with E3 scramble peptide): 0.18 10(4)  m(-1) ; Ka Gd-DTPA-R826sc(gadolinium ((1-p-isothiocyanatobenzyl)-diethylenetriaminepentaacetate) grafted with R826 scramble peptide): 0.32 10(4)  m(-1) ) even if the conjugation of E3 and R826 seems to decrease their interaction. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Web Search Agents: "One-Stop Shopping" for Researchers.

    ERIC Educational Resources Information Center

    Perez, Ernest

    2002-01-01

    Explains Web search agents as tools that apply intelligent agent software technology for the purpose of automating, improving, and speeding up online search operations. Topics include intelligent desktop agents; search agent marketplace; comparing Web search agents; subjective evaluations; and use by researchers. (LRW)

  1. Agent planning in AgScala

    NASA Astrophysics Data System (ADS)

    Tošić, Saša; Mitrović, Dejan; Ivanović, Mirjana

    2013-10-01

    Agent-oriented programming languages are designed to simplify the development of software agents, especially those that exhibit complex, intelligent behavior. This paper presents recent improvements of AgScala, an agent-oriented programming language based on Scala. AgScala includes declarative constructs for managing beliefs, actions and goals of intelligent agents. Combined with object-oriented and functional programming paradigms offered by Scala, it aims to be an efficient framework for developing both purely reactive, and more complex, deliberate agents. Instead of the Prolog back-end used initially, the new version of AgScala relies on Agent Planning Package, a more advanced system for automated planning and reasoning.

  2. Late gadolinium enhanced cardiovascular magnetic resonance of lamin A/C gene mutation related dilated cardiomyopathy

    PubMed Central

    2011-01-01

    Background The purpose of this study was to identify early features of lamin A/C gene mutation related dilated cardiomyopathy (DCM) with cardiovascular magnetic resonance (CMR). We characterise myocardial and functional findings in carriers of lamin A/C mutation to facilitate the recognition of these patients using this method. We also investigated the connection between myocardial fibrosis and conduction abnormalities. Methods Seventeen lamin A/C mutation carriers underwent CMR. Late gadolinium enhancement (LGE) and cine images were performed to evaluate myocardial fibrosis, regional wall motion, longitudinal myocardial function, global function and volumetry of both ventricles. The location, pattern and extent of enhancement in the left ventricle (LV) myocardium were visually estimated. Results Patients had LV myocardial fibrosis in 88% of cases. Segmental wall motion abnormalities correlated strongly with the degree of enhancement. Myocardial enhancement was associated with conduction abnormalities. Sixty-nine percent of our asymptomatic or mildly symptomatic patients showed mild ventricular dilatation, systolic failure or both in global ventricular analysis. Decreased longitudinal systolic LV function was observed in 53% of patients. Conclusions Cardiac conduction abnormalities, mildly dilated LV and depressed systolic dysfunction are common in DCM caused by a lamin A/C gene mutation. However, other cardiac diseases may produce similar symptoms. CMR is an accurate tool to determine the typical cardiac involvement in lamin A/C cardiomyopathy and may help to initiate early treatment in this malignant familiar form of DCM. PMID:21689390

  3. A complement to the modern crystallographer's toolbox: caged gadolinium complexes with versatile binding modes.

    PubMed

    Stelter, Meike; Molina, Rafael; Jeudy, Sandra; Kahn, Richard; Abergel, Chantal; Hermoso, Juan A

    2014-06-01

    A set of seven caged gadolinium complexes were used as vectors for introducing the chelated Gd(3+) ion into protein crystals in order to provide strong anomalous scattering for de novo phasing. The complexes contained multidentate ligand molecules with different functional groups to provide a panel of possible interactions with the protein. An exhaustive crystallographic analysis showed them to be nondisruptive to the diffraction quality of the prepared derivative crystals, and as many as 50% of the derivatives allowed the determination of accurate phases, leading to high-quality experimental electron-density maps. At least two successful derivatives were identified for all tested proteins. Structure refinement showed that the complexes bind to the protein surface or solvent-accessible cavities, involving hydrogen bonds, electrostatic and CH-π interactions, explaining their versatile binding modes. Their high phasing power, complementary binding modes and ease of use make them highly suitable as a heavy-atom screen for high-throughput de novo structure determination, in combination with the SAD method. They can also provide a reliable tool for the development of new methods such as serial femtosecond crystallography.

  4. Inactivation of Kupffer Cells by Gadolinium Chloride Protects Murine Liver From Radiation-Induced Apoptosis

    SciTech Connect

    Du Shisuo; Qiang Min; Zeng Zhaochong; Ke Aiwu; Ji Yuan; Zhang Zhengyu; Zeng Haiying; Liu Zhongshan

    2010-03-15

    Purpose: To determine whether the inhibition of Kupffer cells before radiotherapy (RT) would protect hepatocytes from radiation-induced apoptosis. Materials and Methods: A single 30-Gy fraction was administered to the upper abdomen of Sprague-Dawley rats. The Kupffer cell inhibitor gadolinium chloride (GdCl3; 10 mg/kg body weight) was intravenously injected 24 h before RT. The rats were divided into four groups: group 1, sham RT plus saline (control group); group 2, sham RT plus GdCl3; group 3, RT plus saline; and group 4, RT plus GdCl3. Liver tissue was collected for measurement of apoptotic cytokine expression and evaluation of radiation-induced liver toxicity by analysis of liver enzyme activities, hepatocyte micronucleus formation, apoptosis, and histologic staining. Results: The expression of interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha was significantly attenuated in group 4 compared with group 3 at 2, 6, 24, and 48 h after injection (p <0.05). At early points after RT, the rats in group 4 exhibited significantly lower levels of liver enzyme activity, apoptotic response, and hepatocyte micronucleus formation compared with those in group 3. Conclusion: Selective inactivation of Kupffer cells with GdCl3 reduced radiation-induced cytokine production and protected the liver against acute radiation-induced damage.

  5. Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets.

    PubMed

    Li, Xiaoming; Wang, Renfa; Qi, Jianpin; Tang, Lihua

    2005-01-01

    The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

  6. Layered gadolinium-based nanoparticle as a novel delivery platform for microRNA therapeutics

    NASA Astrophysics Data System (ADS)

    Yoo, Shannon S.; Razzak, Rene; Bédard, Eric; Guo, Linghong; Shaw, Andrew R.; Moore, Ronald B.; Roa, Wilson H.

    2014-10-01

    Specific expression patterns of microRNA (miRNA) molecules have been linked to cancer initiation, progression, and metastasis. The accumulating evidence for the role of oncogenic or tumor-suppressing miRNAs identified the need for nano-scaled platform that can help deliver nucleotides to modulate miRNAs. Here we report the synthesis of novel layered gadolinium hydroxychloride (LGdH) nanoparticles, a member of the layered double hydroxide (LDH) family, with physiochemical properties suitable for cell uptake and tracing via magnetic resonance (MR) imaging. As a proof of concept, we demonstrate the inhibition of mature miRNA-10b in metastatic breast cancer cell line using LGdH nanoparticle as a delivery platform. Through characterization analysis, we show that nanoparticles are easily and stably loaded with anti-miRNA oligonucleotides (AMO) and efficiently penetrate cell membranes. We demonstrate that AMOs delivered by LGdH nanoparticles remain functional by inducing changes in the expression of its downstream effector and by curbing the invasive properties. Furthermore, we demonstrate the traceability of LGdH nanoparticles via T1 weighted MR imaging. LGdH nanoparticles, which are biocompatible with cells in vitro, provide a promising multifunctional platform for microRNA therapeutics through their diagnostic, imaging, and therapeutic potentials.

  7. Caustic Precipitation of Plutonium and Uranium with Gadolinium as a Neutron Poison

    SciTech Connect

    ANN, VISSER

    2005-04-14

    The caustic precipitation of plutonium (Pu) and uranium (U) from Pu and U containing waste solutions has been investigated to determine whether gadolinium (Gd) could be used as a neutron poison for precipitation with greater than a fissile mass containing both Pu and enriched U. Precipitation experiments were performed using both actual samples and simulant solutions with a range of 2.6-5.16 g/L U and 0-4.3 to 1 U to Pu. Analyses were performed on solutions at intermediate pH to determine the partitioning of elements for accident scenarios. When both Pu and U were present in the solution, precipitation began at pH 4.5 and by pH 7, 99 percent of Pu and U had precipitated. When complete neutralization was achieved at pH greater than 14 with 1.2 M excess OH-, greater than 99 percent of Pu, U, and Gd had precipitated. At pH greater than 14, the particles sizes were larger and the distribution was a single mode. The ratio of hydrogen to fissile atoms in the precipitate was determined after both settling and centrifuging and indicates that sufficient water was associated with the precipitates to provide the needed neutron moderation for Gd to prevent a criticality in solutions containing up to 4.3 to 1 U to Pu and up to 5.16 g/L U.

  8. Caustic Precipitation of Plutonium and Uranium with Gadolinium as a Neutron Poison

    SciTech Connect

    VISSER, ANN E.; BRONIKOWSKI, MICHAEL G.; RUDISILL, TRACY S.

    2005-10-18

    The caustic precipitation of plutonium (Pu) and uranium (U) from Pu and U-containing waste solutions has been investigated to determine whether gadolinium (Gd) could be used as a neutron poison for precipitation with greater than a fissile mass containing both Pu and enriched U. Precipitation experiments were performed using both process solution samples and simulant solutions with a range of 2.6-5.16 g/L U and 0-4.3:1 U:Pu. Analyses were performed on solutions at intermediate pH to determine the partitioning of elements for accident scenarios. When both Pu and U were present in the solution, precipitation began at pH 4.5 and by pH 7, 99% of Pu and U had precipitated. When complete neutralization was achieved at pH > 14 with 1.2 M excess OH{sup -}, greater than 99% of Pu, U, and Gd had precipitated. At pH > 14, the particles sizes were larger and the distribution was a single mode. The ratio of hydrogen:fissile atoms in the precipitate was determined after both settling and centrifuging and indicates that sufficient water was associated with the precipitates to provide the needed neutron moderation for Gd to prevent a criticality in solutions containing up to 4.3:1 U:Pu and up to 5.16 g/L U.

  9. MR of intracranial tumors: Combined use of gadolinium and magnetization transfer

    SciTech Connect

    Kurki, T.; Niemi, P.; Valtonen, S.

    1994-10-01

    To study the potential combined application of gadolinium and magnetization transfer in the MR imaging of intracranial tumors. Twenty-two patients were imaged at low field strength (0.1 T). Corresponding gradient-echo partial saturation images without and with magnetization transfer pulse were produced. Images with intermediate repetition times were obtained in 18 cases; five different sequences were produced in 4 cases. Gadopentetate dimeglumine was used at a dose of 0.1 mmol/kg. Magnetization transfer effect increased the contrast between enhancing lesion and normal brain and the contrast between edema and normal brain; the contrast between enhancing lesion and edema was not significantly changed. On intermediate-repetition-time magnetization transfer images the contrast between enhancing tumor and normal brain and the contrast between edema and normal brain were superior to short-repetition-time magnetization transfer images, but the differentiation between enhancing tumor and edema was poorer. Magnetization transfer can be used to improve contrast in Gd-enhanced MR imaging. Combining magnetization transfer with an intermediate-repetition-time image provides the possibility for displaying both enhancing and nonehancing lesions on a single MR image. 20 refs., 7 figs., 2 tabs.

  10. Metabolomic profiles delineate potential roles for gadolinium chloride in the proliferation or inhibition of Hela cells.

    PubMed

    Long, Xiao-Hui; Yang, Peng-Yuan; Liu, Qiong; Yao, Jun; Wang, Yi; He, Guo-Hua; Hong, Guang-Yan; Ni, Jia-Zuan

    2011-08-01

    Lanthanides (Lns) compounds have been reported to possess contrary effects on cell activity, i.e., promoting cell cycle progression and cell growth by lower concentration treatment, but suppressing cell proliferation and inducing cell apoptosis at higher dosing. However, the cellular processes during the intervention and the possible underlying mechanisms are still not well clarified. Using a combination of high-throughput liquid chromatography (LC) with mass spectrometry (MS), we have investigated the metabolomic profiles of Hela cells following gadolinium chloride (GdCl(3)) treatment in time- and concentration- dependent manners. A total of 48 metabolites released by Hela cells are identified to be differentially expressed (P < 0.05) in different states. Metabolic pathways analyses reveal that the differential metabolites are mainly characterized by increased lipid and amino acid metabolisms and by decreased lipid, amino acid, and carbohydrate metabolisms for cells treated with GdCl(3) at lower and higher concentrations, respectively. Notably, in the higher level GdCl(3) case, the down-expressions of metabolites are predominantly in the glycolytic and the redox pathways. The above results, obtained by using a metabolomic strategy for the first time, disclose that different cell signaling pathways are activated by GdCl(3) treatment with different concentrations, leading to inhibitory or promotional effect on Hela cells.

  11. Optical properties of color centers in calcium-stabilized gadolinium gallium garnets

    SciTech Connect

    Pogatshnik, G.J. ); Cain, L.S. ); Chen, Y. ); Evans, B.D. )

    1991-01-15

    The addition of small amounts of calcium during the crystal growth of large-diameter, gadolinium gallium garnet (GGG) crystals creates color centers that absorb in the near-uv region of the spectrum. Ultraviolet and {gamma}-ray irradiation of the crystals produced changes in the intensities of the uv color-center bands along with a broad absorption throughout the visible spectrum. The color center that gives rise to an absorption band at 350 nm serves as a photoionizable donor center so that uv excitation results in a visible coloration of the crystals. The effects of oxidation and reduction treatments on the strength of the color-center bands and on the radiation response of the material were examined. Photoluminescence bands were observed in both reduced GGG crystals as well as crystals that were irradiated with neutrons. Visible coloration is likely to occur during flashlamp pumping of laser rods that utilize large-diameter GGG crystals as the laser host. The changes in the optical properties of the material under uv excitation indicate that the addition of small amounts of calcium to assist in the growth of large-diameter crystals is likely to result in the degradation of laser performance.

  12. Thermal-Diffusivity Dependence on Temperature of Gadolinium Calcium Oxoborate Single Crystals

    NASA Astrophysics Data System (ADS)

    Trefon-Radziejewska, D.; Bodzenta, J.; Łukasiewicz, T.

    2013-05-01

    Thermal diffusivities of pure and doped gadolinium calcium oxoborate (GdCOB) single crystals were measured as a function of the temperature along optical indicatrix axes X, Y, and Z. Three GdCOB samples were investigated, chemically pure single crystal, the one doped with 4 at% of Nd and the next one doped with 7 at% of Yb. Measurements were carried out for temperature range 40 °C to 300 °C. Determination of the thermal diffusivity based on an analysis of thermal wave propagation in the sample. For a detection of temperature disturbance propagating in the sample the mirage effect was used. Obtained results show that the thermal diffusivity decreases with the increase of sample temperature for all investigated crystals. The GdCOB single crystals reveal a strong anisotropy. The thermal diffusivity along Y direction has the highest value while values obtained in X and Z axes are much lower. Dopants cause decrease in the thermal diffusivity for all investigated directions.

  13. Gadolinium dosimetry, a problematic issue in the neutron capture therapy. Comparison between experiments and computational simulations.

    NASA Astrophysics Data System (ADS)

    Bufalino, D.; Cerullo, N.; Colli, V.; Gambarini, G.; Rosi, G.

    2006-05-01

    In GdNCT the interested isotope is 157Gd that captures neutrons with (n, ) reaction and also emits internal conversion and Auger electrons. These electrons have an important effect on DNA strands, mainly due to the property of gadolinium to link to DNA. The emitted gamma rays partially interacts with tumours but mainly diffuse in the body damaging healthy tissues. Therefore in the study of Gd therapeutical effect both dosimetric and microdosimetric analyses must be performed. At Pisa University, in the last years some works were performed by NCT group. At the present these researches are continued on these topics carrying out also a PhD thesis. In this frame some simulations, using MC code, were performed in order to evaluate the dose distribution due to Gd reactions. It is however necessary to calibrate the calculations on experimental results, though they are scarce in GdNCT. Some experiments with 157Gd were performed by Milan group using gel dosimetry [1, 2, 3]. Therefore some computational comparisons were done. In these article the results of this comparisons are shown and discussed.

  14. Random lasing in Nd{sup 3+} doped potassium gadolinium tungstate crystal powder

    SciTech Connect

    Moura, André L.; Fewo, Serge I.; Carvalho, Mariana T.; Gomes, Anderson S. L.; Araújo, Cid B. de; Kuzmin, Andrey N.; Prasad, Paras N.

    2015-02-28

    Random laser (RL) emission in Nd{sup 3+} doped potassium gadolinium tungstate—KGd(WO{sub 4}){sub 2}:Nd{sup 3+}—crystal powder is demonstrated. The powder was excited at 813 nm in resonance with the Nd{sup 3+} transition {sup 4}I{sub 9/2}→{sup 4}F{sub 5/2}. RL emission at 1067 nm due to the {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} transition was observed and characterized. An intensity threshold dependent on the laser spot area and bandwidth narrowing from ≈2.20 nm to ≈0.40 nm were observed and measured. For a beam spot area of 0.4 mm{sup 2}, a RL threshold of 6.5 mJ/mm{sup 2} (90 MW/cm{sup 2}) was determined. For excitation intensity smaller than the RL threshold, only spontaneous emission from level {sup 4}F{sub 3/2} with decay time in the tens microsecond range was observed, but for excitation above the RL threshold, significant shortening of excited level lifetime, characteristic of a stimulated process was found. The overall characteristics measured show that KGd(WO{sub 4}){sub 2}:Nd{sup 3+} is an efficient material for operation of solid state RLs in the near-infrared.

  15. Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature

    SciTech Connect

    Acharya, S. A. Gaikwad, V. M.; Sathe, V.; Kulkarni, S. K.

    2014-03-17

    Correlation between atomic positional shift, oxygen vacancy defects, and oxide ion conductivity in doped ceria system has been established in the gadolinium doped ceria system from X-ray diffraction (XRD) and Raman spectroscopy study at operating temperature (300–600 °C) of Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). High temperature XRD data are used to quantify atomic positional shift from mean position with temperature. The Raman spectroscopy study shows additional vibration modes related to ordering of defect spaces (Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup *} and (2Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup x} generated due to association of oxygen vacancies and reduced cerium or dopant cations site (Gd{sup 3+}), which disappear at 450 °C; indicating oxygen vacancies dissociation from the defect complex. The experimental evidences of cation-anion positional shifting and oxygen vacancies dissociation from defect complex in the IT-SOFC operating temperature are discussed to correlate with activation energy for ionic conductivity.

  16. Performance improvement of gadolinium oxide resistive random access memory treated by hydrogen plasma immersion ion implantation

    SciTech Connect

    Wang, Jer-Chyi Hsu, Chih-Hsien; Ye, Yu-Ren; Ai, Chi-Fong; Tsai, Wen-Fa

    2014-03-15

    Characteristics improvement of gadolinium oxide (Gd{sub x}O{sub y}) resistive random access memories (RRAMs) treated by hydrogen plasma immersion ion implantation (PIII) was investigated. With the hydrogen PIII treatment, the Gd{sub x}O{sub y} RRAMs exhibited low set/reset voltages and a high resistance ratio, which were attributed to the enhanced movement of oxygen ions within the Gd{sub x}O{sub y} films and the increased Schottky barrier height at Pt/Gd{sub x}O{sub y} interface, respectively. The resistive switching mechanism of Gd{sub x}O{sub y} RRAMs was dominated by Schottky emission, as proved by the area dependence of the resistance in the low resistance state. After the hydrogen PIII treatment, a retention time of more than 10{sup 4} s was achieved at an elevated measurement temperature. In addition, a stable cycling endurance with the resistance ratio of more than three orders of magnitude of the Gd{sub x}O{sub y} RRAMs can be obtained.

  17. Modelling of the Gadolinium Fuel Test IFA-681 using the BISON Code

    SciTech Connect

    Pastore, Giovanni; Hales, Jason Dean; Novascone, Stephen Rhead; Spencer, Benjamin Whiting; Williamson, Richard L

    2016-05-01

    In this work, application of Idaho National Laboratory’s fuel performance code BISON to modelling of fuel rods from the Halden IFA-681 gadolinium fuel test is presented. First, an overview is given of BISON models, focusing on UO2/UO2-Gd2O3 fuel and Zircaloy cladding. Then, BISON analyses of selected fuel rods from the IFA-681 test are performed. For the first time in a BISON application to integral fuel rod simulations, the analysis is informed by detailed neutronics calculations in order to accurately capture the radial power profile throughout the fuel, which is strongly affected by the complex evolution of absorber Gd isotopes. In particular, radial power profiles calculated at IFE–Halden Reactor Project with the HELIOS code are used. The work has been carried out in the frame of the collaboration between Idaho National Laboratory and Halden Reactor Project. Some slide have been added as an Appendix to present the newly developed PolyPole-1 algorithm for modeling of intra-granular fission gas release.

  18. Internalization pathways into cancer cells of gadolinium-based radiosensitizing nanoparticles.

    PubMed

    Rima, Wael; Sancey, Lucie; Aloy, Marie-Thérèse; Armandy, Emma; Alcantara, Gustavo B; Epicier, Thierry; Malchère, Annie; Joly-Pottuz, Lucile; Mowat, Pierre; Lux, François; Tillement, Olivier; Burdin, Béatrice; Rivoire, Annie; Boulé, Christelle; Anselme-Bertrand, Isabelle; Pourchez, Jérémie; Cottier, Michèle; Roux, Stéphane; Rodriguez-Lafrasse, Claire; Perriat, Pascal

    2013-01-01

    Over the last few decades, nanoparticles have been studied in theranostic field with the objective of exhibiting a long circulation time through the body coupled to major accumulation in tumor tissues, rapid elimination, therapeutic potential and contrast properties. In this context, we developed sub-5 nm gadolinium-based nanoparticles that possess in vitro efficient radiosensitizing effects at moderate concentration when incubated with head and neck squamous cell carcinoma cells (SQ20B). Two main cellular internalization mechanisms were evidenced and quantified: passive diffusion and macropinocytosis. Whereas the amount of particles internalized by passive diffusion is not sufficient to induce in vitro a significant radiosensitizing effect, the cellular uptake by macropinocytosis leads to a successful radiotherapy in a limited range of particles incubation concentration. Macropinocytosis processes in two steps: formation of agglomerates at vicinity of the cell followed by their collect via the lamellipodia (i.e. the "arms") of the cell. The first step is strongly dependent on the physicochemical characteristics of the particles, especially their zeta potential that determines the size of the agglomerates and their distance from the cell. These results should permit to control the quantity of particles internalized in the cell cytoplasm, promising ambitious opportunities towards a particle-assisted radiotherapy using lower radiation doses.

  19. Purificaiton of Lanthanides for Large Neutrino Detectors: Thorium Removal from Gadolinium Chloride

    SciTech Connect

    Yeh, M.; Cumming, J.B.; Hans, S.; Hahn, R.L.

    2010-06-01

    Metal-loaded liquid scintillators are the detectors of choice for various neutrino experiments. Procedures have been developed to transfer metals into organic liquids by solvent extraction or direct dissolution of a metallic compound. Traces of natural radioactivity introduced into the scintillator with the metal may produce undesirable backgrounds. Measurements using a {sup 229}Th tracer indicate that the inclusion of a pH-controlled partial hydrolysis and filtration prior to the preparation of a gadolinium-loading compound can reduce thorium by a factor of {approx}100. This 'self-scavenging' procedure has the advantage that it uses only reagents encountered in the production process. Addition of non-elemental scavengers such as iron, or the use of solvent extraction or ion exchange procedures can be avoided. It also improves the optical transmission in the blue region by removing traces of iron. This purification method has potential applications to the large-scale production of other metal-loaded liquid scintillators and for the removal of traces of thorium in the industrial production of lanthanides.

  20. Hybrid mercuric iodide (HgI/sub 2/): gadolinium orthosilicate (GSO) detector for PET

    SciTech Connect

    Dahlbom, M.; Barton, J.B.; Hoffman, E.J.; Mandelkern, M.; Ricci, A.R.

    1985-02-01

    Gadolinium orthosilicate (GSO), a high density (6.71 g/cm/sup 3/), high effective Z (59) scintillation detector with faster decay time (60 ns) and higher light yield than bismuth germanate (BGO), was evaluated as a replacement for BGO for a hybrid detection system for high resolution Positron Emission Tomography (PET). The detection system consists of multiple GSO detectors attached to a single photomultiplier tube (PMT) and a HgI/sub 2/ photodetector attached to each GSO crystal. The PMT signal provides coincidence timing and energy discrimination and the photodetector signal identifies the crystal of interaction. GSO light yield was 1.7 times that of BGO with energy resolution consistent with improved photon statistics (17.8 to 13.8% FWHM). Resolution of GSO coupled to a HgI/sub 2/ photodetector was 13.6% FWHM. Coincidence timing was 2.3 ns FWHM. Timing between PMT and HgI/sub 2/ was 136 ns FWHM.

  1. Optical constants determination of neodymium and gadolinium in the 3-nm to 100-nm wavelength range

    NASA Astrophysics Data System (ADS)

    Kjornrattanawanich, B.; Windt, D. L.; Uspenskii, Y. A.; Seely, J. F.

    2006-08-01

    The optical constants (n, k) of the wavelength-dependent index of refraction N = n+ik = 1-δ+ik of Nd (Neodymium) and Gd (Gadolinium) are determined in the wavelength range of 3 nm to 100 nm by the transmittance method using synchrotron radiation. Nd and Gd films with thicknesses ranging from 5 nm to 180 nm were fabricated on Si photodiodes (which served as the coating substrates as well as the detectors) and capped with Si layers to protect these reactive rare earth elements from oxidation. The imaginary part (k) obtained directly from the transmittance measurement is used in the derivation of the real part (δ) of the complex index of refraction N through the Kramers- Kronig integral. The measured optical constants are used in the design of currently developed Nd- and Gd-based multilayers for solar imaging applications. Our results on Nd and Gd optical constants and the reflectance of some Nd- and Gd-based multilayers are presented.

  2. Whole-core comet solutions to a 3-dimensional PWR benchmark problem with gadolinium

    SciTech Connect

    Zhang, D.; Rahnema, F.

    2012-07-01

    A pressurized water reactor (PWR) benchmark problem with gadolinium was used to determine the accuracy and computational efficiency of the coarse mesh radiation transport method COMET. The benchmark problem contains 193 square fuel assemblies. The COMET solution (eigenvalue, assembly averaged and fuel pin averaged fission density distributions) was compared with those obtained from the corresponding Monte Carlo reference solution using the same 2-group material cross section library. The comparison showed that both the core eigenvalue and fission density distribution averaged over each assembly and fuel pin predicated by COMET agree very well with the corresponding MCNP reference solution if the incident flux response expansion used in COMET is truncated at 2nd order in the two spatial and the two angular variables. The benchmark calculations indicate that COMET has Monte Carlo accuracy. In, particular, the eigenvalue difference between the codes ranged from 17 pcm to 35 pcm, being within 2 standard deviations of the calculational uncertainty. The mean flux weighted relative differences in the assembly and fuel pin fission densities were 0.47% and 0.65%, respectively. It was also found that COMET's full (whole) core computational speed is 30,000 times faster than MCNP in which only 1/8 of the core is modeled. It is estimated that COMET would have been about over 6 orders of magnitude faster than MCNP if the full core were also modeled in MCNP. (authors)

  3. Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

    SciTech Connect

    Elphic, R.C.; Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Maurice, S.; Binder, A.B.; Lucey, P.G.

    1999-04-01

    Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.

  4. Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content

    NASA Astrophysics Data System (ADS)

    Moure, Alessandro; Reichmann, Peter; Remigio Gamba, Humberto

    2003-12-01

    The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s-1, in steps of 1 mm s-1, for a total distance of 250 mm. The prototype was evaluated with a phantom of the third metacarpal bone made of perspex and aluminium, and in vitro with a transverse slice of the third metacarpal bone of a horse. The tests showed that the prototype has an accuracy and precision of, approximately, 10% and 6%, respectively, for a 6 s acquisition time. Preliminary studies carried out in three foals from birth to one year of age indicated that the prototype is well suited to in vivo and in situ analysis of the BMD of the third metacarpal bones of horses, making it possible to evaluate the changes of BMD levels on a monthly basis. Also, results indicated an exponential behaviour of the BMD curve during the first year of life of the studied horses.

  5. The influence of gadolinium and yttrium on biomass production and nutrient balance of maize plants.

    PubMed

    Saatz, Jessica; Vetterlein, Doris; Mattusch, Jürgen; Otto, Matthias; Daus, Birgit

    2015-09-01

    Rare earth elements (REE) are expected to become pollutants by enriching in the environment due to their wide applications nowadays. The uptake and distribution of gadolinium and yttrium and its influence on biomass production and nutrient balance was investigated in hydroponic solution experiments with maize plants using increasing application doses of 0.1, 1 and 10 mg L(-1). It could be shown that concentrations of up to 1 mg L(-1) of Gd and Y did not reduce or enhance the plant growth or alter the nutrient balance. 10 mg L(-1) Gd or Y resulted in REE concentrations of up to 1.2 weight-% in the roots and severe phosphate deficiency symptoms. Transfer rates showed that there was only little transport of Gd and Y from roots to shoots. Significant correlations were found between the concentration of Gd and Y in the nutrient solution and the root tissue concentration of Ca, Mg and P.

  6. Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields.

    PubMed

    Williams, A M; Beeley, P A; Spyrou, N M

    2004-01-01

    Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.

  7. Magnetic properties of gadolinium and carbon co-doped gallium nitride

    NASA Astrophysics Data System (ADS)

    Syed Kaleemullah, N.; Ramsubramanian, S.; Mohankumar, R.; Munawar Basha, S.; Rajagopalan, M.; Kumar, J.

    2017-01-01

    Investigations have been carried out to study the ferromagnetic properties of Gadolinium (Gd) Carbon (C) co-doped wurtzite Gallium Nitride (GaN) using full-potential linear augmented plane wave (FP-LAPW) method within the density functional theory. The system shows half-metallic nature when single Gd is substituted in Ga36N36 supercell. The presence of carbon in GaN supercell is found to generate weak magnetic moment (Ms) in the neighbouring atoms. When Carbon is codoped in the Gd-GaN, it increased the total magnetic moment of the system (Mtot). The cause of ferromagnetism in the Gd and C co-doped GaN has been explained by Zener's p-d exchange mechanism. The role of defects in the magnetic property of this system is also investigated. The results indicate the gallium vacancy influences the magnetic moment of the Gd and C codoped GaN more than the nitrogen vacancy. The presence of holes is effective than electrons in achieving the ferromagnetism in the considered system.

  8. Design of a novel optical sensor for determination of trace gadolinium.

    PubMed

    Zare-Dorabei, R; Norouzi, P; Ganjali, M R

    2009-11-15

    In this work, a highly selective and sensitive gadolinium (Gd) optical sensor based on immobilization of bis(thiophenal) pyridine-2,6-diamine (BPD), on a triacetylcellulose membrane has been reported. This optode exhibits a linear range of the Gd(III) ion concentration of 2.5 x 10(-6)M with a detection limit of 0.93 x 10(-8) M. Response time of the newly designed optode was within 1-2 min, depending on the Gd(III) ion concentration. Response of the sensor is independent of solution pH in the range of 2.0-9.0. It manifests advantages of: low detection limit, fast response time, and most significantly, very good selectivity with respect to a number of lanthanide ions (La, Ce, Sm, Tm, Ho, and Eu ions). The sensor was successfully regenerated with thiourea solutions and its response was reversible and reproducible (R.S.D. less than 1.4%). This optode was applied to determine Gd(III) in synthetic and water samples, and validated with certified reference materials (CRMs).

  9. Nutritional therapies (including fosteum).

    PubMed

    Nieves, Jeri W

    2009-03-01

    Nutrition is important in promoting bone health and in managing an individual with low bone mass or osteoporosis. In adult women and men, known losses of bone mass and microarchitecture occur, and nutrition can help minimize these losses. In every patient, a healthy diet with adequate protein, fruits, vegetables, calcium, and vitamin D is required to maintain bone health. Recent reports on nutritional remedies for osteoporosis have highlighted the importance of calcium in youth and continued importance in conjunction with vitamin D as the population ages. It is likely that a calcium intake of 1200 mg/d is ideal, and there are some concerns about excessive calcium intakes. However, vitamin D intake needs to be increased in most populations. The ability of soy products, particularly genistein aglycone, to provide skeletal benefit has been recently studied, including some data that support a new medical food marketed as Fosteum (Primus Pharmaceuticals, Scottsdale, AZ).

  10. Hydroxypyridonate chelating agents and synthesis thereof

    DOEpatents

    Raymond, K.N.; Scarrow, R.C.; White, D.L.

    1985-11-12

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided. 4 tabs.

  11. Three-dimensional segmentation of the left ventricle in late gadolinium enhanced MR images of chronic infarction combining long- and short-axis information.

    PubMed

    Wei, Dong; Sun, Ying; Ong, Sim-Heng; Chai, Ping; Teo, Lynette L; Low, Adrian F

    2013-08-01

    Automatic segmentation of the left ventricle (LV) in late gadolinium enhanced (LGE) cardiac MR (CMR) images is difficult due to the intensity heterogeneity arising from accumulation of contrast agent in infarcted myocardium. In this paper, we present a comprehensive framework for automatic 3D segmentation of the LV in LGE CMR images. Given myocardial contours in cine images as a priori knowledge, the framework initially propagates the a priori segmentation from cine to LGE images via 2D translational registration. Two meshes representing respectively endocardial and epicardial surfaces are then constructed with the propagated contours. After construction, the two meshes are deformed towards the myocardial edge points detected in both short-axis and long-axis LGE images in a unified 3D coordinate system. Taking into account the intensity characteristics of the LV in LGE images, we propose a novel parametric model of the LV for consistent myocardial edge points detection regardless of pathological status of the myocardium (infarcted or healthy) and of the type of the LGE images (short-axis or long-axis). We have evaluated the proposed framework with 21 sets of real patient and four sets of simulated phantom data. Both distance- and region-based performance metrics confirm the observation that the framework can generate accurate and reliable results for myocardial segmentation of LGE images. We have also tested the robustness of the framework with respect to varied a priori segmentation in both practical and simulated settings. Experimental results show that the proposed framework can greatly compensate variations in the given a priori knowledge and consistently produce accurate segmentations.

  12. Preparing Change Agents for Change Agent Roles.

    ERIC Educational Resources Information Center

    Sedlacek, James R.

    Seventy-seven Spanish- and Portuguese-speaking agricultural change agents from developing Central and South American countries responded to a questionnaire which sought perceptions of the roles in which the change agents felt they were involved and the roles for which they felt they were being trained. The agents were participating in training…

  13. Polyion complex micelle MRI contrast agents from poly(ethylene glycol)-b-poly(l-lysine) block copolymers having Gd-DOTA; preparations and their control of T(1)-relaxivities and blood circulation characteristics.

    PubMed

    Shiraishi, Kouichi; Kawano, Kumi; Maitani, Yoshie; Yokoyama, Masayuki

    2010-12-01

    The current study synthesized macromolecular magnetic resonance imaging (MRI) contrast agents constituted of the poly(ethylene glycol)-b-poly(L-lysine) block copolymer (PEG-P(Lys)). A chelate group, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), was attached to the primary amino group of the block copolymer in desired contents. Gd-DOTA-based macromolecular contrast agents were prepared from PEG-P(Lys) having DOTA (PEG-P(Lys-DOTA) and Gd(III) ions. All of the PEG-P(Lys) block copolymers having gadolinium ions (PEG-P(Lys-DOTA-Gd)) showed higher T(1) relaxivity (per gadolinium), r(1)=5.6-7.3mM(-1)s(-1), than that of a low-molecular-weight gadolinium-chelate, diethylenetriaminepentaacetic acid-gadolinium(III) (Gd-DTPA) at 9.4T. The study prepared the polyion complex (PIC) micelles from the amino groups of the lysine units and an oppositely charged polyanion, poly(methacrylic acid) or dextran sulfate, in an aqueous medium. In contrast, the fully DOTA-attached PEG-P(Lys-DOTA-Gd) formed a PIC with a polycation. Compared with partially DOTA-attached cationic PEG-P(Lys-DOTA-Gd), this PIC micelle yielded a forty percent decrease of r(1). This r(1) decrease was considered to result from a change in the accessibility of water molecules to gadolinium ions in the micelles' inner core. The r(1) was decreased upon formation of the PIC micelle, and this change proved that our concept worked in vitro. Blood-circulation characteristics of PIC micelles were controlled by means of changing the molecular weight of the counter anion. The PIC micelles accumulated in tumor tissues, and MRI study showed T1W image of axial slice of tumor area was significantly enhanced at 24h after the injection.

  14. A neutral polydisulfide containing Gd(III) DOTA monoamide as a redox-sensitive biodegradable macromolecular MRI contrast agent.

    PubMed

    Ye, Zhen; Zhou, Zhuxian; Ayat, Nadia; Wu, Xueming; Jin, Erlei; Shi, Xiaoyue; Lu, Zheng-Rong

    2016-01-01

    This work aims to develop safe and effective gadolinium (III)-based biodegradable macromolecular MRI contrast agents for blood pool and cancer imaging. A neutral polydisulfide containing macrocyclic Gd-DOTA monoamide (GOLS) was synthesized and characterized. In addition to studying the in vitro degradation of GOLS, its kinetic stability was also investigated in an in vivo model. The efficacy of GOLS for contrast-enhanced MRI was examined with female BALB/c mice bearing 4T1 breast cancer xenografts. The pharmacokinetics, biodistribution, and metabolism of GOLS were also determined in mice. GOLS has an apparent molecular weight of 23.0 kDa with T1 relaxivities of 7.20 mM(-1) s(-1) per Gd at 1.5 T, and 6.62 mM(-1) s(-1) at 7.0 T. GOLS had high kinetic inertness against transmetallation with Zn(2+) ions, and its polymer backbone was readily cleaved by L-cysteine. The agent showed improved efficacy for blood pool and tumor MR imaging. The structural effect on biodistribution and in vivo chelation stability was assessed by comparing GOLS with Gd(HP-DO3A), a negatively charged polydisulfide containing Gd-DOTA monoamide GODC, and a polydisulfide containing Gd-DTPA-bisamide (GDCC). GOLS showed high in vivo chelation stability and minimal tissue deposition of gadolinium. The biodegradable macromolecular contrast agent GOLS is a promising polymeric contrast agent for clinical MR cardiovascular imaging and cancer imaging.

  15. Nanoengineered multimodal contrast agent for medical image guidance

    NASA Astrophysics Data System (ADS)

    Perkins, Gregory J.; Zheng, Jinzi; Brock, Kristy; Allen, Christine; Jaffray, David A.

    2005-04-01

    Multimodality imaging has gained momentum in radiation therapy planning and image-guided treatment delivery. Specifically, computed tomography (CT) and magnetic resonance (MR) imaging are two complementary imaging modalities often utilized in radiation therapy for visualization of anatomical structures for tumour delineation and accurate registration of image data sets for volumetric dose calculation. The development of a multimodal contrast agent for CT and MR with prolonged in vivo residence time would provide long-lasting spatial and temporal correspondence of the anatomical features of interest, and therefore facilitate multimodal image registration, treatment planning and delivery. The multimodal contrast agent investigated consists of nano-sized stealth liposomes encapsulating conventional iodine and gadolinium-based contrast agents. The average loading achieved was 33.5 +/- 7.1 mg/mL of iodine for iohexol and 9.8 +/- 2.0 mg/mL of gadolinium for gadoteridol. The average liposome diameter was 46.2 +/- 13.5 nm. The system was found to be stable in physiological buffer over a 15-day period, releasing 11.9 +/- 1.1% and 11.2 +/- 0.9% of the total amounts of iohexol and gadoteridol loaded, respectively. 200 minutes following in vivo administration, the contrast agent maintained a relative contrast enhancement of 81.4 +/- 13.05 differential Hounsfield units (ΔHU) in CT (40% decrease from the peak signal value achieved 3 minutes post-injection) and 731.9 +/- 144.2 differential signal intensity (ΔSI) in MR (46% decrease from the peak signal value achieved 3 minutes post-injection) in the blood (aorta), a relative contrast enhancement of 38.0 +/- 5.1 ΔHU (42% decrease from the peak signal value achieved 3 minutes post-injection) and 178.6 +/- 41.4 ΔSI (62% decrease from the peak signal value achieved 3 minutes post-injection) in the liver (parenchyma), a relative contrast enhancement of 9.1 +/- 1.7 ΔHU (94% decrease from the peak signal value achieved 3 minutes

  16. Refraction, including prisms.

    PubMed

    Hiatt, R L

    1991-02-01

    The literature in the past year on refraction is replete with several isolated but very important topics that have been of interest to strabismologists and refractionists for many decades. The refractive changes in scleral buckling procedures include an increase in axial length as well as an increase in myopia, as would be expected. Tinted lenses in dyslexia show little positive effect in the nonasthmatic patients in one study. The use of spectacles or bifocals as a way to control increase in myopia is refuted in another report. It has been shown that in accommodative esotropia not all patients will be able to escape the use of bifocals in the teenage years, even though surgery might be performed. The hope that disposable contact lenses would cut down on the instance of giant papillary conjunctivitis and keratitis has been given some credence, and the conventional theory that sclerosis alone is the cause of presbyopia is attacked. Also, gas permeable bifocal contact lenses are reviewed and the difficulties of correcting presbyopia by this method outlined. The practice of giving an aphakic less bifocal addition instead of a nonaphakic, based on the presumption of increased effective power, is challenged. In the review of prisms, the majority of articles concern prism adaption. The most significant report is that of the Prism Adaptation Study Research Group (Arch Ophthalmol 1990, 108:1248-1256), showing that acquired esotropia in particular has an increased incidence of stable and full corrections surgically in the prism adaptation group versus the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility.

    PubMed

    Krasznai, Zoltán; Morisawa, Masaaki; Krasznai, Zoárd Tibor; Morisawa, Sachiko; Inaba, Kazuo; Bazsáné, Zsuzsa Kassai; Rubovszky, Bálint; Bodnár, Béla; Borsos, Antal; Márián, Teréz

    2003-08-01

    Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin-Ca(2+) interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 +/- 3% to 6 +/- 3% and that of carp sperm from 91 +/- 7% to 3.5 +/- 4.3% in a dose-dependent manner (10-40 micro M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm.

  18. Pulse electrosynthesis of novel wormlike gadolinium oxide nanostructure and its nanocomposite with conjugated electroactive polymer as a hybrid and high efficient electrode material for energy storage device.

    PubMed

    Shiri, Hamid Mohammad; Ehsani, Ali

    2016-12-15

    An effective approach for increasing the life cycle of pure p-type conductive polymers is combining conventional conductive polymers and nanomaterials to fabricate hybrid electrodes. In this paper, Gadolinium oxide (Gd2O3) has first been synthesized using pulse electrochemical approach. Hybrid POAP/Gd2O3 films have then been fabricated by POAP electropolymerization in the presence of Gd2O3 nanoparticles as active electrodes for electrochemical supercapacitors. Surface and electrochemical analyses have been used for characterization of Gd2O3 and POAP/Gd2O3 composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Specific capacitance, specific energy and specific power of the composite film are calculated 300F·g(-1), 41.66Wh·kg(-1) and 833.22W·kg(-1) respectively. This work introduces new nanocomposite materials for electrochemical redox capacitors with such advantages as the ease of synthesis, high active surface area and stability in an aqueous electrolyte.

  19. Newer antifungal agents.

    PubMed

    Türel, Ozden

    2011-03-01

    The frequency and spectrum of fungal infections have been increasing steadily over the last several decades. The reason for this increase may be explained by the increase in the number of immunocompromised patients due to malignancies, AIDS, invasive surgical procedures and transplantation. In parallel with this increase, several therapeutic options have become available but problems such as intrinsic or acquired antifungal resistance have led researchers to develop new antifungal drugs with expanded effectiveness. Reduced toxicity, enhancement of bioavailability and counteraction of resistance are features desired by clinicians. The aim of this article is to summarize the studies involving isavuconazole, ravuconazole, albaconazole, aminocandin and some other investigational antifungal agents. Most data on the clinical use of ravuconazole, isavuconazole and albaconazole are mainly available as meeting abstracts or limited to animal studies or Phase I/II studies in humans. These new antifungal agents in development offer extended half-lives, possibly reduced drug interaction profiles and good tolerance. In addition to activity against Candida and Aspergillus spp., they have a broad spectrum of activity including activity against resistant and emerging pathogens. The real possibilities of these agents will only be fully understood after adequate randomized clinical trials.

  20. Mechanostereoselective One-Pot Synthesis of Functionalized Head-to-Head Cyclodextrin [3]Rotaxanes and Their Application as Magnetic Resonance Imaging Contrast Agents.

    PubMed

    Fredy, Jean Wilfried; Scelle, Jérémy; Ramniceanu, Gregory; Doan, Bich-Thuy; Bonnet, Célia S; Tóth, Éva; Ménand, Mickaël; Sollogoub, Matthieu; Vives, Guillaume; Hasenknopf, Bernold

    2017-02-21

    A versatile, five-component, one-pot synthesis of cyclodextrin (CD) [3]rotaxanes using copper-catalyzed azide-alkyne cycloaddition has been developed. Head-to-head [3]rotaxanes of α-CD selectively functionalized by one or two gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid monoamide complexes were obtained mechanostereoselectively. The magnetic resonance imaging efficiency, expressed by the longitudinal proton relaxivity of the rotaxanes, was significantly improved as compared to the functionalized CD. In vitro and in vivo preclinical studies showed a higher contrast and retention in the kidney than gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex, demonstrating the potential of these rotaxanes as MRI contrast agent.

  1. Gadolinium Enhanced MRI Assessment of Bone-Patellar Tendon-Bone Graft Harvest on Patellar Vascularity

    PubMed Central

    Jones, Kristofer J.; Lazaro, Lionel E.; Taylor, Samuel; Pardee, Nadine C.; Dyke, Jonathan P.; Hannafin, Jo A.; Warren, Russell F.; Lorich, Dean G.

    2013-01-01

    Objectives: Bone-patellar tendon-bone (BPTB) autograft remains a favored graft source for anterior cruciate ligament (ACL) reconstruction despite problems related to donor-site morbidity. Patellar devascularization has been proposed as a source of anterior knee pain following vascular disruption from traumatic injury (fracture) or surgical procedures involving the patella (total knee arthroplasty); however, no study has investigated the effect of BPTB harvest on patellar vascularity. Recent anatomic studies have suggested that the dominant arterial supply enters the patella through the inferior pole. We hypothesized that BPTB harvest can significantly diminish patellar vascularity following graft harvest. Methods: Nine matched pair cadaveric knee specimens (mean age 47.4 years) were dissected and cannulated at the superficial femoral, anterior tibialis, and posterior tibialis arteries. A single knee was randomly selected to undergo bone graft harvest. The contralateral knee was left intact to serve as a control. Gadolinium (Gd-DPTA) was injected into each knee and MRI signal enhancement was quantified to determine differences in osseous uptake between the two knees. Following MRI assessment, each matched pair was injected with a urethane polymer compound and dissected to correlate vessel disruption with MRI findings. Results: Graft harvest resulted in a mean 31% (range, 7.1-69.5%) decrease in signal enhancement when compared to the matched control. MRI assessment revealed two predominant patterns of vessel entry for the dominant inferior arterial supply. In one pattern, the vessel entered the inferomedial aspect (∼7 o’clock) of the distal patellar pole and was disrupted by bone graft harvest in two matched pairs (2/9, 22%). In the second pattern, the predominant vessel entered further medial (∼8 o’clock) and was not disrupted in 7 matched pairs. The mean decrease in gadolinium uptake following disruption of the predominant vessel measured 56% (range, 42

  2. Enhanced electron mobility at gadolinium oxide(100)/silicon(100) interface: Origin and applications

    NASA Astrophysics Data System (ADS)

    Sitaputra, Wattaka

    A growth of a gadolinium oxide (Gd2O3) layer with (100) orientation on a Si(100) substrate was obtained for the first time using molecular beam epitaxy deposition (MBE) with the growth temperature in the range of 150-200°C and the oxygen partial pressure in the range of 10 -7-10-6 Torr. The growth was performed on three type of Si(100) substrate; n-type, p-type, and intrinsic. Among the three major orientations, i.e. (111), (110) and (100), the Gd2O3(100) is known from energetic point of view to be least favorable. Nonetheless, an enhancement in electron mobility can only be found from the interface between Gd2O3(100) and Si(100). Although p-type Si(100) results in the best structural considerations from x-ray diffraction among the three types of substrate, the best feature was observed in the Gd2O 3(100)/n-type Si(100) because of its highest mobility enhancement and satisfactory structural stability. The mobility of 1670-1780 cm2/V˙s was observed at room temperature, for carrier concentration > 1018 cm-3. This amounts to a factor of four higher in electron mobility compared to a heavily doped n-type substrate with similar carrier concentration. This accumulation of electrons and mobility enhancement are attributed to two-dimensional confinement from charges transfer across the interface quite similar to modulation doping. Owing to these properties, the Gd2O3(100) becomes a promising candidate in promoting the scaling of logic devices.

  3. Erosion Performance of Gadolinium Zirconate-Based Thermal Barrier Coatings Processed by Suspension Plasma Spray

    NASA Astrophysics Data System (ADS)

    Mahade, Satyapal; Curry, Nicholas; Björklund, Stefan; Markocsan, Nicolaie; Nylén, Per; Vaßen, Robert

    2017-01-01

    7-8 wt.% Yttria-stabilized zirconia (YSZ) is the standard thermal barrier coating (TBC) material used by the gas turbines industry due to its excellent thermal and thermo-mechanical properties up to 1200 °C. The need for improvement in gas turbine efficiency has led to an increase in the turbine inlet gas temperature. However, above 1200 °C, YSZ has issues such as poor sintering resistance, poor phase stability and susceptibility to calcium magnesium alumino silicates (CMAS) degradation. Gadolinium zirconate (GZ) is considered as one of the promising top coat candidates for TBC applications at high temperatures (>1200 °C) due to its low thermal conductivity, good sintering resistance and CMAS attack resistance. Single-layer 8YSZ, double-layer GZ/YSZ and triple-layer GZdense/GZ/YSZ TBCs were deposited by suspension plasma spray (SPS) process. Microstructural analysis was carried out by scanning electron microscopy (SEM). A columnar microstructure was observed in the single-, double- and triple-layer TBCs. Phase analysis of the as-sprayed TBCs was carried out using XRD (x-ray diffraction) where a tetragonal prime phase of zirconia in the single-layer YSZ TBC and a cubic defect fluorite phase of GZ in the double and triple-layer TBCs was observed. Porosity measurements of the as-sprayed TBCs were made by water intrusion method and image analysis method. The as-sprayed GZ-based multi-layered TBCs were subjected to erosion test at room temperature, and their erosion resistance was compared with single-layer 8YSZ. It was shown that the erosion resistance of 8YSZ single-layer TBC was higher than GZ-based multi-layered TBCs. Among the multi-layered TBCs, triple-layer TBC was slightly better than double layer in terms of erosion resistance. The eroded TBCs were cold-mounted and analyzed by SEM.

  4. Neutralization of Plutonium and Enriched Uranium Solutions Containing Gadolinium as a Neutron Poison

    SciTech Connect

    BRONIKOWSKI, MG.

    2004-04-01

    Materials currently being dissolved in the HB-Line Facility will result in an accumulated solution containing an estimated uranium:plutonium (U:Pu) ratio of 4.3:1 and an 235U enrichment estimated at 30 per cent The U:Pu ratio and the enrichment are outside the evaluated concentration range for disposition to high level waste (HLW) using gadolinium (Gd) as a neutron poison. To confirm that the solution generated during the current HB-Line dissolving campaign can be poisoned with Gd, neutralized and discarded to the Savannah River Site (SRS) high level waste (HLW) system without undue nuclear safety concerns the caustic precipitation of surrogate solutions was examined. Experiments were performed with a U/Pu/Gd solution representative of the HB-Line estimated concentration ratio and also a U/Gd solution. Depleted U was used in the experiments as the enrichment of the U will not affect the chemical behavior during neutralization, but will affect the amount of Gd added to the solution. Settling behavior of the neutralized solutions was found to be comparable to previous studies. The neutralized solutions mixed easily and had expected densities of typical neutralized waste. The neutralized solids were found to be homogeneous and less than 20 microns in size. Partially neutralized solids were more amorphous than the fully neutralized solids. Based on the results of these experiments, Gd was found to be a viable poison for neutralizing a U/Pu/Gd solution with a U:Pu mass ratio of 4.3:1 thus extending the U:Pu mass ratio from the previously investigated 0-3:1 to 4.3:1. However, further work is needed to allow higher U concentrations or U:Pu ratios greater than investigated in this work.

  5. Convection enhanced delivery of different molecular weight tracers of gadolinium-tagged polylysine.

    PubMed

    Hardy, Peter A; Keeley, Dan; Schorn, Greg; Forman, Eric; Ai, Yi; Venugopalan, Ramakrishna; Zhang, Zhiming; Bradley, Luke H

    2013-09-30

    Convection enhanced delivery (CED) is a powerful method of circumventing the blood-brain barrier (BBB) to deliver therapeutic compounds directly to the CNS. While inferring the CED distribution of a therapeutic compound by imaging a magnetic resonance (MR)-sensitive tracer has many advantages, however how the compound distribution is affected by the features of the delivery system, its target tissue, and its molecular properties, such as its binding characteristics, charge, and molecular weight (MW) are not fully understood. We used MR imaging of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-tagged polylysine compounds of various MW, in vitro and in vivo, to measure the dependence of compounds MW on CED distribution. For the in vitro studies, the correlation between volume of distribution (Vd) as a function of MW was determined by measuring the T1 of the infused tracers, into 0.6% agarose gels through a multiport catheter. The compounds distributed in the gels inversely proportional to their MW, consistent with convection and unobstructed diffusion through a porous media. For the in vivo studies, Gd-DTPA tagged compounds were infused into the non-human primate putamen, via an implanted multiport catheter connected to a MedStream™ pump, programmed to deliver a predetermined volume with alternating on-off periods to take advantage of the convective and diffusive contributions to Vd. Unlike the gel studies, the higher MW polylysine-tracer infusions did not freely distribute from the multiport catheter in the putamen, suggesting that distribution was impeded by other properties that should also be considered in future tracer design and CED infusion protocols.

  6. Strength and structural phase transitions of gadolinium at high pressure from radial X-ray diffraction

    SciTech Connect

    Xiong, Lun Liu, Jing; Bai, Ligang; Li, Xiaodong; Lin, Chuanlong; Lin, Jung-Fu

    2014-12-28

    Lattice strength and structural phase transitions of gadolinium (Gd) were determined under nonhydrostatic compression up to 55 GPa using an angle-dispersive radial x-ray diffraction technique in a diamond-anvil cell at room temperature. Three new phases of fcc structure, dfcc structure, and new monoclinic structure were observed at 25 GPa, 34 GPa, and 53 GPa, respectively. The radial x-ray diffraction data yield a bulk modulus K{sub 0} = 36(1) GPa with its pressure derivate K{sub 0}′ = 3.8(1) at the azimuthal angle between the diamond cell loading axis and the diffraction plane normal and diffraction plane ψ = 54.7°. With K{sub 0}′ fixed at 4, the derived K{sub 0} is 34(1) GPa. In addition, analysis of diffraction data with lattice strain theory indicates that the ratio of differential stress to shear modulus (t/G) ranges from 0.011 to 0.014 at pressures of 12–55 GPa. Together with estimated high-pressure shear moduli, our results show that Gd can support a maximum differential stress of 0.41 GPa, while it starts to yield to plastic deformation at 16 GPa under uniaxial compression. The yield strength of Gd remains approximately a constant with increasing pressure, and reaches 0.46 GPa at 55 GPa.

  7. Modification of Mg{sub 2}Si in Mg–Si alloys with gadolinium

    SciTech Connect

    Ye, Lingying; Hu, Jilong Tang, Changping; Zhang, Xinming; Deng, Yunlai; Liu, Zhaoyang; Zhou, Zhile

    2013-05-15

    The modification effect of gadolinium (Gd) on Mg{sub 2}Si in the hypereutectic Mg–3 wt.% Si alloy has been investigated using optical microscope, scanning electron microscope, X-ray diffraction and hardness measurements. The results indicate that the morphology of the primary Mg{sub 2}Si is changed from coarse dendrite into fine polygon with the increasing Gd content. The average size of the primary Mg{sub 2}Si significantly decreases with increasing Gd content up to 1.0 wt.%, and then slowly increases. Interestingly, when the Gd content is increased to 4.0 and 8.0 wt.%, the primary and eutectic Mg{sub 2}Si evidently decrease and even disappear. The modification and refinement of the primary Mg{sub 2}Si is mainly attributed to the poisoning effect. The GdMg{sub 2} phase in the primary Mg{sub 2}Si is obviously coarsened as the Gd content exceeds 2.0 wt.%. While the decrease and disappearance of the primary and eutectic Mg{sub 2}Si are ascribed to the formation of vast GdSi compound. Therefore, it is reasonable to conclude that proper Gd (1.0 wt.%) addition can effectively modify and refine the primary Mg{sub 2}Si. - Highlights: ► Proper Gd (1.0 wt.%) addition can effectively modify and refine the primary Mg{sub 2}Si. ► We studied the reaction feasibility between Mg and Si, Gd and Si in Mg–Gd–Si system. ► We explored the modification mechanism of Gd modifier on Mg{sub 2}Si.

  8. Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis

    PubMed Central

    Tian, Bing; Liu, Ri; Chen, Shiyue; Chen, Luguang; Liu, Fang; Jia, Guorong; Dong, Yinmei; Li, Jing; Chen, Huaiwen; Lu, Jianping

    2017-01-01

    Background Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP. Methods We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated. Results The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T1 imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T1 magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats. Conclusion Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future. PMID:28260882

  9. Influence of geochemical parameters on the sorption and desorption behaviour of europium and gadolinium onto kaolinite.

    PubMed

    Kautenburger, Ralf; Beck, Horst P

    2010-06-01

    In this study we investigated the sorption and desorption behaviour of europium and gadolinium (homologues of the actinides americium and curium) onto the clay mineral kaolinite KGa-1b. In the model system metal/kaolinite, sorption isotherms and pH-edges were determined in different batch experiments. Calcium and magnesium as competing cations were used to simulate the influence of water hardness on the sorption and desorption processes. After centrifugation, the free metal ions in the supernatant solution were analysed by ICP-MS. With increasing lanthanide concentration, especially the relative desorption of these metals from kaolinite rises significantly before the cation exchange capacity (CEC) of 0.94 meq per 100 g is reached. This indicates that low lanthanide concentrations will result in a relatively lower metal migration due to sorption reactions at higher active sites in comparison with higher lanthanide concentrations. The K(d)-values and sorption isotherms of Eu(iii) and Gd(iii) were determined at pH 5.0 (+/-0.02) and analysed with Freundlich and Langmuir sorption models. The experimental data can best be fitted by Langmuir sorption isotherm. The pH-value has only a minor influence on the sorption onto kaolinite. Only at low pH-values (

  10. Enhanced Quantum Cutting via Li(+) Doping from a Bi(3+)/Yb(3+)-Codoped Gadolinium Tungstate Phosphor.

    PubMed

    Yadav, Ran Vijay; Yadav, Ram Sagar; Bahadur, Amresh; Singh, Akhilesh Kumar; Rai, Shyam Bahadur

    2016-11-07

    The Bi(3+)/Yb(3+)-codoped gadolinium tungstate phosphor has been synthesized through a solid-state reaction method. The structural characterization reveals the crystalline nature of the phosphor. The Bi(3+)-doped phosphor emits visible radiation from the blue to red regions upon excitation with 330 and 355 nm. The addition of Yb(3+) to the Bi(3+)-doped phosphor reduces the emission intensity in the visible region and emits an intense near-infrared (NIR) photon centered at 976 nm through a quantum-cutting (QC) phenomenon. This is due to cooperative energy transfer (CET) from the (3)P1 level of Bi(3+) to the (2)F5/2 level of Yb(3+). The presence of Li(+) ions in the Bi(3+)/Yb(3+)-codoped phosphor enhances the emission intensity in the NIR region up to by 3 times, whereas the emission intensity in the visible region is significantly reduced. The energy transfer (ET) from the Bi(3+) ions to the Yb(3+) ions is confirmed by lifetime measurements, and the lifetime for the (3)P1 level of Bi(3+) decreases continuously with increasing Yb(3+) concentration. The ET efficiency (ηETE) and corresponding QC efficiency (ηQE) are calculated and found to be 29% and 129%, respectively. The presence of Li(+) enhances the QC efficiency of the phosphor up to 43%. Thus, the Bi(3+)/Yb(3+)/Li(+)-codoped phosphor is a promising candidate to enhance the efficiency of a crystalline-silicon-based solar cell through spectral conversion.

  11. Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement.

    PubMed

    Kebed, Kalie Y; Al Adham, Raed I; Bishu, Kalkidan; Askew, J Wells; Klarich, Kyle W; Araoz, Philip A; Foley, Thomas A; Glockner, James F; Nishimura, Rick A; Anavekar, Nandan S

    2014-09-01

    Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

  12. Intelligent Agent Architectures: Reactive Planning Testbed

    NASA Technical Reports Server (NTRS)

    Rosenschein, Stanley J.; Kahn, Philip

    1993-01-01

    An Integrated Agent Architecture (IAA) is a framework or paradigm for constructing intelligent agents. Intelligent agents are collections of sensors, computers, and effectors that interact with their environments in real time in goal-directed ways. Because of the complexity involved in designing intelligent agents, it has been found useful to approach the construction of agents with some organizing principle, theory, or paradigm that gives shape to the agent's components and structures their relationships. Given the wide variety of approaches being taken in the field, the question naturally arises: Is there a way to compare and evaluate these approaches? The purpose of the present work is to develop common benchmark tasks and evaluation metrics to which intelligent agents, including complex robotic agents, constructed using various architectural approaches can be subjected.

  13. Biodegradable polydisulfide dendrimer nanoclusters as MRI contrast agents.

    PubMed

    Huang, Ching-Hui; Nwe, Kido; Al Zaki, Ajlan; Brechbiel, Martin W; Tsourkas, Andrew

    2012-11-27

    Gadolinium-conjugated dendrimer nanoclusters (DNCs) are a promising platform for the early detection of disease; however, their clinical utility is potentially limited due to safety concerns related to nephrogenic systemic fibrosis (NSF). In this paper, biodegradable DNCs were prepared with polydisulfide linkages between the individual dendrimers to facilitate excretion. Further, DNCs were labeled with premetalated Gd chelates to eliminate the risk of free Gd becoming entrapped in dendrimer cavities. The biodegradable polydisulfide DNCs possessed a circulation half-life of >1.6 h in mice and produced significant contrast enhancement in the abdominal aorta and kidneys for as long as 4 h. The DNCs were reduced in circulation as a result of thiol-disulfide exchange, and the degradation products were rapidly excreted via renal filtration. These agents demonstrated effective and prolonged in vivo contrast enhancement and yet minimized Gd tissue retention. Biodegradable polydisulfide DNCs represent a promising biodegradable macromolecular MRI contrast agent for magnetic resonance angiography and can potentially be further developed into target-specific MRI contrast agents.

  14. Fabrication and characterization of novel boron and gadolinium rich power generation and real-time neutron detection materials and devices

    NASA Astrophysics Data System (ADS)

    Natta, Marcus L.

    In this work, the neutron capture capabilities of two naturally occurring isotopes, gadolinium-157 (157Gd) and boron-10 (10B), were investigated for use as neutron detecting diodes. The appeal of using 157Gd and 10B is due to their large thermal neutron absorption cross sections: gadolinium (on average ˜46,000 barns) and boron-10 (˜3800 barns). Boron carbide (B4C) films were grown on nickel, copper, silver, and aluminum substrates using plasma enhanced chemical vapor deposition (PECVD) techniques forming p-n junctions using various configurations of two isomers: closo-1,7-dicarbadodecaborane (metacarborane) or closo-1,7-phosphacaborane (phosphacarborane) for the n-type layers and closo-1,2-dicarbadodecaborane (orthocarborane) for the p-type layer. These all-boron carbide heterojunction diodes were investigated experimentally, with highly sensitive current voltage measurements in light and dark and under alpha, beta, and neutron irradiation. The heteroisomeric diodes exhibited photovoltaic and alphavoltaic behavior and successfully functioned as neutron detectors. Preliminary results of beta radiation response of these heteroisomeric diodes is also presented. The high-kappa dielectric oxide, hafnium oxide (HfO2), was doped with gadolinium and grown on silicon using pulsed laser deposition (PLD) to form a novel semiconducting diode. Three levels of Gd-doping (3%, 10%, and 15%) were explored. A shift from the unstable monoclinic phase to the stable cubic phase is seen with increased Gd-doping concentrations, which may possibly serve as a better semiconductor. The detection of charge pulses created by neutron capture was explored using neutron sources from Nebraska Wesleyan University and The Ohio State University Research Reactor (OSURR) neutron sources. The 10% and 15% doped diodes exhibited pulse height spectra in the presence of neutrons. Electronic signal processing remains the most significant challenge for these latter detectors.

  15. Contrast agent Gd-EOB-DTPA (EOB·Primovist®) for low-field magnetic resonance imaging of canine focal liver lesions.

    PubMed

    Yonetomi, Daisuke; Kadosawa, Tsuyoshi; Miyoshi, Kenjirou; Nakao, Yukie; Homma, Emi; Hanazono, Kiwamu; Yamada, Eriko; Nakamura, Kozo; Ijiri, Atsuki; Minegishi, Noriyuki; Maetani, Shigeki; Hirayama, Kazuko; Taniyama, Hiroyuki; Nakade, Tetsuya

    2012-01-01

    Contrast-enhanced magnetic resonance (MR) imaging with a new liver-specific contrast agent gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA; EOB·Primovist®) was studied in 14 normal beagles and 9 dogs with focal liver lesions. Gd-EOB-DTPA accumulates in normally functioning hepatocytes 20 min after injection. As with Gd-DTPA, it is also possible to perform a dynamic multiphasic examination of the liver with Gd-EOB-DTPA, including an arterial phase and a portal venous phase. First, a reliable protocol was developed and the appropriate timings for the dynamic study and the parenchymal phase in normal dogs using Gd-EOB-DTPA were determined. Second, the patterns of these images were evaluated in patient dogs with hepatic masses. The optimal time of arterial imaging was from 15 s after injection, and the optimal time for portal venous imaging was from 40 s after injection. Meanwhile, the optimal time to observe changes during the hepatobiliary phase was from 20 min after injection. In patient dogs, 11 lesions were diagnosed as malignant tumors; all were hypointense to the surrounding normal liver parenchyma during the hepatobiliary phase. Even with a low-field MR imaging unit, the sequences afforded images adequate to visualize the liver parenchyma and to detect tumors within an appropriate scan time. Contrast-enhanced MR imaging with Gd-EOB-DTPA provides good demarcation on low-field MR imaging for diagnosing canine focal liver lesions.

  16. Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging Post-robotic Radiosurgical Pulmonary Vein Isolation (RRPVI): First Case in the World

    PubMed Central

    Azpiri, Jose; De La Peña, Cuauhtémoc; Cardona, Carlos; Hinojosa, Miguel; Zamarripa, Rafael; Assad, Jose

    2016-01-01

    Pulmonary vein isolation using robotic radiosurgery system CyberKnife is a new non-invasive treatment of atrial fibrillation, currently in clinical phase. Robotic radiosurgical pulmonary vein isolation (RRPVI) uses stereotactic, non-invasive (painless) pinpoint radiation energy delivery to a small, precise area to accomplish ablation. The purpose of this report is to describe the finding of an increase in the enhancement of the left atrium demonstrated with the use of cardiac magnetic resonance imaging using late gadolinium enhancement (LGE-CMR) as a result of RRPVI in the first case in the world in humans using CyberKnife as a treatment for paroxysmal atrial fibrillation (PAF). PMID:27660737

  17. Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging Post-robotic Radiosurgical Pulmonary Vein Isolation (RRPVI): First Case in the World.

    PubMed

    Monroy, Edgar; Azpiri, Jose; De La Peña, Cuauhtémoc; Cardona, Carlos; Hinojosa, Miguel; Zamarripa, Rafael; Assad, Jose

    2016-08-15

    Pulmonary vein isolation using robotic radiosurgery system CyberKnife is a new non-invasive treatment of atrial fibrillation, currently in clinical phase. Robotic radiosurgical pulmonary vein isolation (RRPVI) uses stereotactic, non-invasive (painless) pinpoint radiation energy delivery to a small, precise area to accomplish ablation. The purpose of this report is to describe the finding of an increase in the enhancement of the left atrium demonstrated with the use of cardiac magnetic resonance imaging using late gadolinium enhancement (LGE-CMR) as a result of RRPVI in the first case in the world in humans using CyberKnife as a treatment for paroxysmal atrial fibrillation (PAF).

  18. Band-gap modulation via gallium substitution in cerium doped gadolinium aluminum garnet using a mixed fuel combustion approach

    SciTech Connect

    Tyagi, Mohit; Pitale, Shreyas S.; Ghosh, Manoranjan; Shinde, Seema

    2014-04-24

    Cerium doped Gadolinium garnets (Gd{sub 3}Al{sub x}Ga{sub 5−x}O{sub 12} where 0≤x≤5) are synthesized via combustion synthesis using mixture of urea and glycine fuels. A 4h Post annealing at 1400 oC is found to be necessary for pure phase formation. Lattice spacing variation as a result of partial or total Ga substitution at Al site was mapped by X-ray diffraction. Photoluminescence emission of Ce shifts as a consequence of Ga substitution and therefore suggests a local re-adjustment of crystal field around activator site.

  19. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    DOEpatents

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  20. Study of iodine, gadolinium and bismuth quantification possibility with micro-CT IVIS spectrumct in vivo imaging system

    NASA Astrophysics Data System (ADS)

    Pervova, V. V.; Lipengolts, A. A.; Cherepanov, A. A.; Abakumov, M. A.

    2017-01-01

    The main task of radiotherapy is to create prescribed absorbed dose of irradiation in a tumor with minimal damage of healthy tissues. Contrast Enhanced Radiotherapy allows to achieve that by administration of a special drug into the tumor before irradiation, that increases the absorbed dose within the tumor volume. The concentration of the drug determines the value of the absorbed dose, therefore one of the major tasks in CERT is quantification of the drug concentration in the tumor during irradiation procedure. The present work deals with quantitative determination of iodine, gadolinium and bismuth water solutions by use of micro-CT IVIS Spectrum In Vivo Imaging System.

  1. Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions.

    PubMed

    Menahem, Adi; Dror, Ishai; Berkowitz, Brian

    2016-02-01

    The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions.

  2. Gadolinium-Functionalized Peptide Amphiphile Micelles for Multimodal Imaging of Atherosclerotic Lesions

    PubMed Central

    2016-01-01

    The leading causes of morbidity and mortality globally are cardiovascular diseases, and nanomedicine can provide many improvements including disease-specific targeting, early detection, and local delivery of diagnostic agents. To this end, we designed fibrin-binding, peptide amphiphile micelles (PAMs), achieved by incorporating the targeting peptide cysteine-arginine-glutamic acid-lysine-alanine (CREKA), with two types of amphiphilic molecules containing the gadoliniuim (Gd) chelator diethylenetriaminepentaacetic acid (DTPA), DTPA-bis(stearylamide)(Gd), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[(poly(ethylene glycol) (PEG))-2000]-DTPA(Gd) (DSPE-PEG2000-DTPA(Gd)). The material characteristics of the resulting nanoparticle diagnostic probes, clot-binding properties in vitro, and contrast enhancement and safety for dual, optical imaging–magnetic resonance imaging (MRI) were evaluated in the atherosclerotic mouse model. Transmission electron micrographs showed a homogenous population of spherical micelles for formulations containing DSPE-PEG2000-DTPA(Gd), whereas both spherical and cylindrical micelles were formed upon mixing DTPA-BSA(Gd) and CREKA amphiphiles. Clot-binding assays confirmed DSPE-PEG2000-DTPA(Gd)-based CREKA micelles targeted clots over 8-fold higher than nontargeting (NT) counterpart micelles, whereas no difference was found between CREKA and NT, DTPA-BSA(Gd) micelles. However, in vivo MRI and optical imaging studies of the aortas and hearts showed fibrin specificity was conferred by the peptide ligand without much difference between the nanoparticle formulations or shapes. Biodistribution studies confirmed that all micelles were cleared through both the reticuloendothelial system and renal clearance, and histology showed no signs of necrosis. In summary, these studies demonstrate the successful synthesis, and the molecular imaging capabilities of two types of CREKA-Gd PAMs for atherosclerosis. Moreover, we demonstrate the differences in

  3. Biological warfare agents.

    PubMed

    Pohanka, Miroslav; Kuca, Kamil

    2010-01-01

    Biological warfare agents are a group of pathogens and toxins of biological origin that can be potentially misused for military or criminal purposes. The present review attempts to summarize necessary knowledge about biological warfare agents. The historical aspects, examples of applications of these agents such as anthrax letters, biological weapons impact, a summary of biological warfare agents and epidemiology of infections are described. The last section tries to estimate future trends in research on biological warfare agents.

  4. Spacecraft sanitation agent development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development of an effective sanitizing agent that is compatible with the spacecraft environment and the human occupant is discussed. Experimental results show that two sanitation agents must be used to satisfy mission requirements: one agent for personal hygiene and one for equipment maintenance. It was also recommended that a water rinse be used with the agents for best results, and that consideration be given to using the agents pressure packed or in aerosol formulations.

  5. Anchor Toolkit - a secure mobile agent system

    SciTech Connect

    Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah

    1999-05-19

    Mobile agent technology facilitates intelligent operation insoftware systems with less human interaction. Major challenge todeployment of mobile agents include secure transmission of agents andpreventing unauthorized access to resources between interacting systems,as either hosts, or agents, or both can act maliciously. The Anchortoolkit, designed by LBNL, handles the transmission and secure managementof mobile agents in a heterogeneous distributed computing environment. Itprovides users with the option of incorporating their security managers.This paper concentrates on the architecture, features, access control anddeployment of Anchor toolkit. Application of this toolkit in a securedistributed CVS environment is discussed as a case study.

  6. Achieving agent coordination via distributed preferences

    SciTech Connect

    D`Ambrosio, J.G.; Birmingham, W.P.

    1996-12-31

    Agent-based systems provide hope for solving a wide variety of distributed problems. One key aspect of agent-based system is coordinating agent actions to achieve coherent behavior. For example, in concurrent engineering (CE), it is necessary to ensure that the individual decision made by constituents in a design organization achieve overall organizational objectives (e.g., increase market share), while still allowing individuals to exploit their expertise. We believe CE is representative of many multi-agent problems, in that agent coordination must include facilities to support both solving a hierarchically decomposed problem, e.g., the contract net, and interactions among peers as well.

  7. Chemical warfare agents.

    PubMed

    Kuca, Kamil; Pohanka, Miroslav

    2010-01-01

    Chemical warfare agents are compounds of different chemical structures. Simple molecules such as chlorine as well as complex structures such as ricin belong to this group. Nerve agents, vesicants, incapacitating agents, blood agents, lung-damaging agents, riot-control agents and several toxins are among chemical warfare agents. Although the use of these compounds is strictly prohibited, the possible misuse by terrorist groups is a reality nowadays. Owing to this fact, knowledge of the basic properties of these substances is of a high importance. This chapter briefly introduces the separate groups of chemical warfare agents together with their members and the potential therapy that should be applied in case someone is intoxicated by these agents.

  8. Contrast agent enhanced pQCT of articular cartilage

    NASA Astrophysics Data System (ADS)

    Kallioniemi, A. S.; Jurvelin, J. S.; Nieminen, M. T.; Lammi, M. J.; Töyräs, J.

    2007-02-01

    The delayed gadolinium enhanced MRI of cartilage (dGEMRIC) technique is the only non-invasive means to estimate proteoglycan (PG) content in articular cartilage. In dGEMRIC, the anionic paramagnetic contrast agent gadopentetate distributes in inverse relation to negatively charged PGs, leading to a linear relation between T1,Gd and spatial PG content in tissue. In the present study, for the first time, contrast agent enhanced peripheral quantitative computed tomography (pQCT) was applied, analogously to dGEMRIC, for the quantitative detection of spatial PG content in cartilage. The suitability of two anionic radiographic contrast agents, gadopentetate and ioxaglate, to detect enzymatically induced PG depletion in articular cartilage was investigated. First, the interrelationships of x-ray absorption, as measured with pQCT, and the contrast agent solution concentration were investigated. Optimal contrast agent concentrations for the following experiments were selected. Second, diffusion rates for both contrast agents were investigated in intact (n = 3) and trypsin-degraded (n = 3) bovine patellar cartilage. The contrast agent concentration of the cartilaginous layer was measured prior to and 2-27 h after immersion. Optimal immersion time for the further experiments was selected. Third, the suitability of gadopentetate and ioxaglate enhanced pQCT to detect the enzymatically induced specific PG depletion was investigated by determining the contrast agent concentrations and uronic acid and water contents in digested and intact osteochondral samples (n = 16). After trypsin-induced PG loss (-70%, p < 0.05) the penetration of gadopentetate and ioxaglate increased (p < 0.05) by 34% and 48%, respectively. Gadopentetate and ioxaglate concentrations both showed strong correlation (r = -0.95, r = -0.94, p < 0.01, respectively) with the uronic acid content. To conclude, contrast agent enhanced pQCT provides a technique to quantify PG content in normal and experimentally

  9. Correlation of histological findings with gadolinium enhanced MRI scans during healing of a PHEMA orbital implant in rabbits

    PubMed Central

    Hicks, C.; Morris, I.; Vijayasekaran, S.; Fallon, M.; McAllister, J.; Clayton, A.; Chirila, T.; Crawford, G.; Constable, I.

    1999-01-01

    BACKGROUND/AIMS—To investigate a poly(2-hydroxyethyl methacrylate) (PHEMA) orbital implant with a spongy anterior hemisphere and a smooth gel posterior hemisphere, by histology correlated with magnetic resonance images.
METHODS—Following enucleation, eight rabbits received PHEMA implants to which the muscles were directly sutured, and underwent gadolinium enhanced magnetic resonance imaging (MRI) from 3 to 52 weeks. After the rabbits were killed, the implants were removed, cut in a plane corresponding to the scan, and processed for light and electron microscopy.
RESULTS—All eight rabbits retained their implant to the end of the study period without complications. The scans demonstrated muscle attachment to the anterior half of the implant, and enhancement was seen on injection of gadolinium chelate. Histology confirmed muscle attachment, and cellular and vascular ingrowth. Over time, a transformation from reactive inflammatory to relatively non-vascular scar tissue was seen within the implant. Calcium deposits in one implant were detected by imaging and histology.
CONCLUSION—The implants are readily visualised on MRI. Muscle attachment and fibrovascular ingrowth into the anterior hemisphere are seen, while encapsulation of the posterior hemisphere is minimal. Histological findings confirm the progress of the healing response, with initial inflammation and marked vascularisation, developing later into quiescent scar tissue predominantly of fibroblasts.

 PMID:10216066

  10. Comparative theoretical study of the structures and stabilities of four typical gadolinium carboxylates in different scintillator solvents.

    PubMed

    Huang, Pin-Wen

    2016-03-01

    The structural properties and stabilities of four typical gadolinium carboxylates (Gd-CBX) in toluene, linear alkyl benzene (LAB), and phenyl xylyl ethane (PXE) solvents were theoretically studied using density functional theory (DFT/B3LYP with the basis sets 6-311G(d) and MWB54) and the polarizable continuum model (PCM). The average Gd-ligand interaction energies (E int, corrected for dispersion) and the values of the energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital (ΔHL) for the gadolinium complexes were calculated to compare the relative stabilities of the four Gd-CBX molecules in the three liquid scintillator solvents. According to the calculations, the values of E int and ΔHL for Gd-CBX in LAB are larger than the corresponding values in PXE and toluene. Gd-CBX may therefore be more compatible with LAB than with PXE and toluene. It was also found that, in the three scintillator solvents, the stabilities of the four Gd-CBX molecules increase in the order Gd-2EHA < Gd-2MVA < Gd-pivalate < Gd-TMHA.

  11. Gadolinium-functionalized aggregation-induced emission dots as dual-modality probes for cancer metastasis study.

    PubMed

    Li, Kai; Ding, Dan; Prashant, Chandrasekharan; Qin, Wei; Yang, Chang-Tong; Tang, Ben Zhong; Liu, Bin

    2013-12-01

    Understanding the localization and engraftment of tumor cells at postintravasation stage of metastasis is of high importance in cancer diagnosis and treatment. Advanced fluorescent probes and facile methodologies for cell tracing play a key role in metastasis studies. In this work, we design and synthesize a dual-modality imaging dots with both optical and magnetic contrast through integration of a magnetic resonance imaging reagent, gadolinium(III), into a novel long-term cell tracing probe with aggregation-induced emission (AIE) in far-red/near-infrared region. The obtained fluorescent-magnetic AIE dots have both high fluorescence quantum yield (25%) and T1 relaxivity (7.91 mM(-1) s(-1) ) in aqueous suspension. After further conjugation with a cell membrane penetrating peptide, the dual-modality dots can be efficiently internalized into living cells. The gadolinium(III) allows accurate quantification of biodistribution of cancer cells via intraveneous injection, while the high fluorescence provides engraftment information of cells at single cellular level. The dual-modality AIE dots show obvious synergistic advantages over either single imaging modality and hold great promises in advanced biomedical studies.

  12. Two-dimensional nanoscale imaging of gadolinium spins via scanning probe relaxometry with a single spin in diamond

    NASA Astrophysics Data System (ADS)

    Pelliccione, Matthew; Myers, Bryan; Pascal, Laetitia; Das, Anand; Jayich, Ania

    2015-03-01

    Spin-labeling of molecules with paramagnetic ions is an important approach for determining molecular structure, however current ensemble techniques lack the sensitivity to detect few isolated spins. In this talk, we demonstrate two-dimensional nanoscale imaging of paramagnetic gadolinium compounds using scanning relaxometry of a single nitrogen vacancy (NV) center in diamond. Gadopentetate dimeglumine attached to an atomic force microscope tip is controllably interacted with and detected by the NV center, by virtue of the fact that the NV exhibits fast relaxation in the fluctuating magnetic field generated by electron spin flips in the gadolinium. We demonstrate a reduction in the T1 relaxation time of the NV center by over two orders of magnitude, probed with a spatial resolution of 20 nm, limited by thermal drift in ambient conditions. We discuss the importance of mitigating drift to reach truly nanoscale imaging and present progress towards cryogenic scanning magnetometry, along with utilizing chemically functionalized tips to gain greater control over the Gd distribution on the tip. Our result exhibits the viability of the technique for imaging individual spins attached to complex nanostructures or biomolecules, along with studying the magnetic dynamics of isolated spins.

  13. Effect of particle size on gamma radiation shielding property of gadolinium oxide dispersed epoxy resin matrix composite

    NASA Astrophysics Data System (ADS)

    Li, Ran; Gu, Yizhuo; Wang, Yidong; Yang, Zhongjia; Li, Min; Zhang, Zuoguang

    2017-03-01

    Epoxy resin matrix composites filled with dispersed micro and nano gadolinium oxide (Gd2O3) particles of different contents were fabricated in this study. The γ radiation shielding and mechanical properties of these micro and nano composites were evaluated by measuring mass attenuation coefficients at photon energies from 31 keV to 356 keV and flexural performances. Adding Gd2O3 obviously increases mass attenuation coefficients of composites, and the enhancement is stronger at low photon energy because of dominating photoelectric effect and k-edge of element gadolinium. Effect of Gd2O3 particle size on shielding property of composite was also discussed. The results show that nano-Gd2O3 composites have better ability to shield X and γ ray than micro-Gd2O3 composites, and an enhanced effect of ~28% is obtained with Gd2O3 content of around 5 wt.% at 59.5 keV. The reason is attributed to higher probability of interaction between γ-ray and nano particles. Especially, this effect is prominent in low particle concentration. For flexural property, nano-Gd2O3/epoxy composite show equivalent flexural strength and up to15% higher flexural modulus compared with micro-Gd2O3/epoxy composite. Based on these experimental results, nano-Gd2O3 reinforced epoxy composite is believed to be a promising novel radiation shielding material.

  14. Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

    SciTech Connect

    Nicholas, Jason Dale

    2007-01-01

    Cerium gadolinium oxide (CGO) has been identified as an acceptable solid oxide fuel cell (SOFC) electrolyte at temperatures (500-700 C) where cheap, rigid, stainless steel interconnect substrates can be used. Unfortunately, both the high sintering temperature of pure CGO, >1200 C, and the fact that constraint during sintering often results in cracked, low density ceramic films, have complicated development of metal supported CGO SOFCs. The aim of this work was to find new sintering aids for Ce0.9Gd0.1O1.95, and to evaluate whether they could be used to produce dense, constrained Ce0.9Gd0.1O1.95 films at temperatures below 1000 C. To find the optimal sintering aid, Ce0.9Gd0.1O1.95 was doped with a variety of elements, of which lithium was found to be the most effective. Dilatometric studies indicated that by doping CGO with 3mol% lithium nitrate, it was possible to sinter pellets to a relative density of 98.5% at 800 C--a full one hundred degrees below the previous low temperature sintering record for CGO. Further, it was also found that a sintering aid's effectiveness could be explained in terms of its size, charge and high temperature mobility. A closer examination of lithium doped Ce0.9Gd0.1O1.95 indicated that lithium affects sintering by producing a Li2O-Gd2O3-CeO2 liquid at the CGO grain boundaries. Due to this liquid phase sintering, it was possible to produce dense, crack-free constrained films of CGO at the record low temperature of 950 C using cheap, colloidal spray deposition processes. This is the first time dense constrained CGO films have been produced below 1000 C and could help commercialize metal supported ceria based solid oxide fuel cells.

  15. Plasma-enhanced atomic layer deposition and etching of high-k gadolinium oxide

    SciTech Connect

    Vitale, Steven A.; Wyatt, Peter W.; Hodson, Chris J.

    2012-01-15

    Atomic layer deposition (ALD) of high-quality gadolinium oxide thin films is achieved using Gd(iPrCp){sub 3} and O{sub 2} plasma. Gd{sub 2}O{sub 3} growth is observed from 150 to 350 deg. C, though the optical properties of the film improve at higher temperature. True layer-by-layer ALD growth of Gd{sub 2}O{sub 3} occurred in a relatively narrow window of temperature and precursor dose. A saturated growth rate of 1.4 A/cycle was observed at 250 deg. C. As the temperature increases, high-quality films are deposited, but the growth mechanism appears to become CVD-like, indicating the onset of precursor decomposition. At 250 deg. C, the refractive index of the film is stable at {approx}1.80 regardless of other deposition conditions, and the measured dispersion characteristics are comparable to those of bulk Gd{sub 2}O{sub 3}. XPS data show that the O/Gd ratio is oxygen deficient at 1.3, and that it is also very hygroscopic. The plasma etching rate of the ALD Gd{sub 2}O{sub 3} film in a high-density helicon reactor is very low. Little difference is observed in etching rate between Cl{sub 2} and pure Ar plasmas, suggesting that physical sputtering dominates the etching. A threshold bias power exists below which etching does not occur; thus it may be possible to etch a metal gate material and stop easily on the Gd{sub 2}O{sub 3} gate dielectric. The Gd{sub 2}O{sub 3} film has a dielectric constant of about 16, exhibits low C-V hysteresis, and allows a 50 x reduction in gate leakage compared to SiO{sub 2}. However, the plasma enhanced atomic layer deposition (PE-ALD) process causes formation of an {approx}1.8 nm SiO{sub 2} interfacial layer, and generates a fixed charge of -1.21 x 10{sup 12} cm{sup -2}, both of which may limit use of PE-ALD Gd{sub 2}O{sub 3} as a gate dielectric.

  16. Feature Tracking-Derived Peak Systolic Strain Compared to Late Gadolinium Enhancement in Troponin-Positive Myocarditis: A Case-Control Study.

    PubMed

    Weigand, Justin; Nielsen, James C; Sengupta, Partho P; Sanz, Javier; Srivastava, Shubhika; Uppu, Santosh

    2016-04-01

    Cardiac magnetic resonance (CMR) assesses myocardial involvement in myocarditis (MYO). Current techniques are qualitative, subjective, and prone to interpretation error. Feature tracking (FT) analyzes myocardial strain using CMR and has not been examined in MYO. We hypothesize that regional left ventricular (LV) strain is abnormal in MYO. Regional strain by FT was compared to late gadolinium enhancement (LGE) and troponin leak as measures of myocardial involvement. This single-center, retrospective CMR study reviewed patients with clinical MYO and structurally normal hearts who underwent CMR at our institution. Young adults with normal cardiac anatomy, function, and absent LGE served as controls. MYO patients with documented troponin leak and normal global ejection fraction (EF > 50 %) were included in comparison. FT determined regional myocardial peak systolic strain (pkS) in longitudinal and circumferential distributions. T tests compared strain values between cases and controls. Receiver operating characteristic curves determined pkS values with highest sensitivity and specificity for concurrent troponin leak and LGE. FT was performed on 57 patients: 37 MYO and 20 controls. Twenty-eight cases with normal EF, and 20 control patients were included in final analysis. Nearly all cases with normal function demonstrated abnormal regional pkS (27/28, 96 %). Cases had significantly diminished pkS when compared to controls in all regions except the longitudinal 2C distribution. FT-derived longitudinal and circumferential pkS is sensitive and specific in identifying myocardial involvement, namely the presence of troponin leak and LGE. FT may be a useful adjunctive, objective measure of myocardial involvement in patients with MYO and normal LV function.

  17. [New agents for hypercholesterolemia].

    PubMed

    Pintó, Xavier; García Gómez, María Carmen

    2016-02-19

    An elevated proportion of high cardiovascular risk patients do not achieve the therapeutic c-LDL goals. This owes to physicians' inappropriate or insufficient use of cholesterol lowering medications or to patients' bad tolerance or therapeutic compliance. Another cause is an insufficient efficacy of current cholesterol lowering drugs including statins and ezetimibe. In addition, proprotein convertase subtilisin kexin type 9 inhibitors are a new cholesterol lowering medications showing safety and high efficacy to reduce c-LDL in numerous already performed or underway clinical trials, potentially allowing an optimal control of hypercholesterolemia in most patients. Agents inhibiting apolipoprotein B synthesis and microsomal transfer protein are also providing a new potential to decrease cholesterol in patients with severe hypercholesterolemia and in particular in homozygote familial hypercholesterolemia. Last, cholesteryl ester transfer protein inhibitors have shown powerful effects on c-HDL and c-LDL, although their efficacy in cardiovascular prevention and safety has not been demonstrated yet. We provide in this article an overview of the main characteristics of therapeutic agents for hypercholesterolemia, which have been recently approved or in an advanced research stage.

  18. Solute Transport of Negatively Charged Contrast Agents Across Articular Surface of Injured Cartilage.

    PubMed

    Kokkonen, H T; Chin, H C; Töyräs, J; Jurvelin, J S; Quinn, T M

    2017-04-01

    Solute transport through the extracellular matrix (ECM) is crucial to chondrocyte metabolism. Cartilage injury affects solute transport in cartilage due to alterations in ECM structure and solute-matrix interactions. Therefore, cartilage injury may be detected by using contrast agent-based clinical imaging. In the present study, effects of mechanical injury on transport of negatively charged contrast agents in cartilage were characterized. Using cartilage plugs injured by mechanical compression protocol, effective partition coefficients and diffusion fluxes of iodine- and gadolinium-based contrast agents were measured using high resolution microCT imaging. For all contrast agents studied, effective diffusion fluxes increased significantly, particularly at early times during the diffusion process (38 and 33% increase after 4 min, P < 0.05 for iodine and Gd-DTPA; and 76% increase after 10 min for diatrizoate, P < 0.05). Effective partition coefficients were unaffected in mechanically injured cartilage. Mechanical injury reduced PG content and collagen integrity in cartilage superficial zone. This study suggests that alterations in contrast agent diffusion flux, a non-equilibrium transport parameter, provides a more sensitive indicator for assessment of cartilage matrix integrity than partition coefficient and the equilibrium distribution of solute. These findings may help in developing clinical methods of contrast agent-based imaging to detect cartilage injury.

  19. A liposomal Gd contrast agent does not cross the mouse placental barrier.

    PubMed

    Shetty, Anil N; Pautler, Robia; Ghagahda, Ketan; Rendon, David; Gao, Haijun; Starosolski, Zbigniew; Bhavane, Rohan; Patel, Chandreshkumar; Annapragada, Ananth; Yallampalli, Chandrasekhar; Lee, Wesley

    2016-06-14

    The trans-placental permeability of liposomal Gadolinium (Gd) nanoparticle contrast agents was evaluated in a pregnant mouse model. Pregnant Balb/c mice at 16.5 (±1) days of gestation were imaged using a 3D Spoiled Gradient Echo method at 9.4 T using two contrast agents: a clinically approved Gd chelate, Multihance(®) (gadobenate dimeglumine), and a novel experimental liposomal Gd agent. A Dynamic Contrast Enhancement (DCE) protocol was used to capture the dynamics of contrast entry and distribution in the placenta, and clearance from circulation. A blinded clinical radiologist evaluated both sets of images. A reference region model was used to measure the placental flow and physiological parameters; volume transfer constant (K(trans)), efflux rate constant (K(ep)). The Gd content of excised placentae and fetuses was measured, using inductively coupled plasma mass spectrometry (ICP-MS). MRI images of pregnant mice and ICP-MS analyses of placental and fetal tissue demonstrated undetectably low transplacental permeation of the liposomal Gd agent, while the clinical agent (Multihance) avidly permeated the placental barrier. Image interpretation and diagnostic quality was equivalent between the two contrast agents. Additional testing to determine both maternal and fetal safety of liposomal Gd is suggested.

  20. A liposomal Gd contrast agent does not cross the mouse placental barrier

    PubMed Central

    Shetty, Anil N.; Pautler, Robia; Ghagahda, Ketan; Rendon, David; Gao, Haijun; Starosolski, Zbigniew; Bhavane, Rohan; Patel, Chandreshkumar; Annapragada, Ananth; Yallampalli, Chandrasekhar; Lee, Wesley

    2016-01-01

    The trans-placental permeability of liposomal Gadolinium (Gd) nanoparticle contrast agents was evaluated in a pregnant mouse model. Pregnant Balb/c mice at 16.5 (±1) days of gestation were imaged using a 3D Spoiled Gradient Echo method at 9.4 T using two contrast agents: a clinically approved Gd chelate, Multihance® (gadobenate dimeglumine), and a novel experimental liposomal Gd agent. A Dynamic Contrast Enhancement (DCE) protocol was used to capture the dynamics of contrast entry and distribution in the placenta, and clearance from circulation. A blinded clinical radiologist evaluated both sets of images. A reference region model was used to measure the placental flow and physiological parameters; volume transfer constant (Ktrans), efflux rate constant (Kep). The Gd content of excised placentae and fetuses was measured, using inductively coupled plasma mass spectrometry (ICP-MS). MRI images of pregnant mice and ICP-MS analyses of placental and fetal tissue demonstrated undetectably low transplacental permeation of the liposomal Gd agent, while the clinical agent (Multihance) avidly permeated the placental barrier. Image interpretation and diagnostic quality was equivalent between the two contrast agents. Additional testing to determine both maternal and fetal safety of liposomal Gd is suggested. PMID:27298076