Search results for "Ion exchange resins"
showing 10 items of 20 documents
PURINE AND PYRIMIDINE NUCLEOTIDES IN THE BRAIN OF NORMAL AND CONVULSANT RATS
1969
— Purine and pyrimidine nucleotides were measured in the brain of normal and electroshocked rats after chromatographic separation on ion-exchange resin of mono-, di- and tri-phosphorylated derivatives. CMP, IMP and NAD did not show any significant quantitative change. Adenine nucleotides showed an abrupt change followed by a rapid return to the control value. GTP was the only purine nucleotide exhibiting a relatively slow return to its starting concentration. The greatest percentage increase after electroshock was observed in UMP, which returned to its control value only after 5 min; UDPCoenzymes (i.e. UDPA plus UDPG) showed a relatively small drop during the development of the seizure and …
Scandium-44: Benefits of a Long-Lived PET Radionuclide Available from the 44Ti/44Sc Generator System
2011
(44)Ti/(44)Sc radionuclide generators are of interest for molecular imaging. The 3.97 hours half-life of (44)Sc and its high positron branching of 94.27% may stimulate the application of (44)Sc-labeled PET radiopharmaceuticals. This review describes the current status of (44)Ti production, (44)Ti/(44)Sc radionuclide generator development, post-processing of generator eluates towards medical application, identification of ligands adequate to Sc(III) co-ordination chemistry, proof-of-principle labeling of (44)Sc-DOTA-octreotides, investigation of in vitro and in vivo parameters, and initial applications for molecular imaging - both in small animals and humans.
Solidification of ion exchange resins saturated with Na+ ions: Comparison of matrices based on Portland and blast furnace slag cement
2017
International audience; Ion exchange resins (IERs) are widely used by the nuclear industry to decontaminate radioactive effluents. After use, they are usually stabilized and solidified by encapsulation in cementitious materials. However, for certain combinations of cement and resins, the solidified waste forms can exhibit strong expansion, possibly leading to cracking of the matrix. In this work, the behaviour of cationic resins in the Na$^+$ form is investigated in Portland cement (CEM I) or blast furnace slag cement (CEM III/C) pastes at early age in order to have a better understanding of the swelling process. The results show that during the hydration of the CEM I paste, the resins exhi…
The human chromophobe cell renal carcinoma: its probable relation to intercalated cells of the collecting duct.
1988
In the present study we have examined ten cases of the chromophobe type renal cell carcinoma. This type of tumor is distinguished from the other carcinomas of the kidney with light cytoplasm (formerly called “hypernephroid”) by (a) a positive Hale’s iron colloid stain of the cytoplasm, (b) the occurrence of numerous invaginated vesicles within the cytoplasm that resemble the invaginated vesicles of intercalated cells of the collecting duct system, and (c) a positive immunoreaction of both the plasma membrane and the cytoplasm with antibodies to the epithelial membrane antigen (EMA) and carbonic anhydrase C (CAC), respectively. Unlike oncocytomas, which also express CAC and EMA, the chromoph…
Determination of total ribonucleotide pool in plant materials by high-pH anion-exchange high-performance liquid chromatography following extraction w…
2005
A new, improved method that only requires a potassium hydroxide extraction procedure is presented for the analysis of a full nucleotide pool in plant materials. Quantification was performed by high-pH anion-exchange chromatography (HPAEC) with UV detection after a potassium hydroxide extraction, and allowed the quantification of 13 linear ribonucleotides in a single run. The method has been validated by comparison of six extraction methods and also by measurement of the intracellular nucleotide levels of three plant species (cell cultures and leaves). The evolution of the nucleotide pool of Nicotiana tabacum cell culture during growth has also been measured, and showed an increase in the po…
Potent Aroma Compounds of Two Red Wine Vinegars
2000
Gas chromatography olfactometry (GCO) was used to determine key aroma compounds of two red wine vinegars. Sensory analysis was performed to choose the best neutralization agent of acetic acid (NaOH or MgO) and to test representativeness of four extracts obtained by different methods (dichloromethane extraction, XAD-2, mixture of XAD-2 and XAD-7, and Extrelut resins extraction). Neutralization with NaOH followed by dichloromethane extraction was selected to extract volatile compounds of vinegars. Key odorant compounds were determined by GCO based on detection frequency with 13 people. In the two red wine vinegars, 13 odors were perceived by at least 70% of the panelists, and 8 compounds amon…
Hydrophobic and cation exchange mechanisms in the retention of basic compounds in a polymeric column.
2004
A cation exchange retention mechanism concomitant with the well-known hydrophobic partition mechanism in a polymeric column has been observed and investigated. This exchange process is attributed to ionization of some acidic sites present in the polymer column at basic mobile phase pH values. Several drugs of different basicity have been chromatographed on a polymeric PLRP-S column with methanol-water and acetonitrile-water mobile phases. The cation exchange between the protonated basic drug and the buffer cations (Na+, K+ and BuNH4+) is observed at the pH range where the protonated drug and the ionized sites of the column coexist. This process produces a shift of the retention versus pH pl…
Maturation of a Key Resource – The Germanium-68/Gallium-68 Generator: Development and New Insights
2011
(68)Ge/(68)Ga radionuclide generators have been investigated for almost fifty years, since the cyclotron-independent availability of positron emitting (68)Ga via the (68)Ge/(68)Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally reach a level of (68)Ge/(68)Ga radionuclide generator designs adequate to the modern requirements of radiometal labelling chemistry. Nevertheless, most of the existing commercial generator systems address aspects of (68)Ge breakthrough and safe synthesis of (68)Ga radiopharmaceuticals by adopting eluate post-processing …
Cationic lipide mediated transfer of c-abl and bcr antisense oligonucleotides to immature normal myeloid cells: Uptake, biological effects and modula…
1996
Uptake and biochemical and biological effects of antisense oligodeoxynucleotides (ODN) specific for c-abl and bcr genes were studied in normal immature myeloid cells. CD34-positive cells were purified by positive and negative selection and cultured in liquid culture for 7 days. These cells were then incubated with ODNs, either alone or in combination with cationic lipids. The uptake of ODNs was enhanced by the use of cationic lipids. In addition, very low concentrations of ODNs in combination with cationic lipids were capable of specifically inhibiting the expression of the c-abl gene. In contrast, no effects were seen on the expression of bcr. However, despite the effective blocking of c-a…
Adsorption of methotrexate and calcium leucovorin onto cholestyramine in vitro.
2003
Abstract Methotrexate (MTX), an antimetabolite of folic acid, is a drug widely used in the treatment of different types of cancer. When high doses are administered, it is necessary to interrupt its action by administering calcium leucovorin (CaL). The main pathway of MTX and CaL elimination in humans occurs through the kidney, but about 10% is excreted in the faeces via the bile. Drugs, foods and sorbents in intestinal lumen modify MTX and CaL reabsorption. Individual and simultaneous studies on the adsorption of MTX and CaL from aqueous phosphate buffer by cholestyramine were carried out in order to calculate the adsorption process of MTX and CaL to cholestyramine, and to characterize the …