scholarly journals Thermochromatographic separation of 45Ti and subsequent radiosynthesis of [45Ti]salan

2020 ◽  
Vol 326 (2) ◽  
pp. 1281-1287
Author(s):  
Kai Giesen ◽  
Ingo Spahn ◽  
Bernd Neumaier
Keyword(s):  
Solvent Extraction ◽  
Tumor Imaging ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Extraction Techniques ◽  
Metabolic Fate ◽  
Widespread Application ◽  
Decay Properties ◽  
Scandium Chloride

Abstract Due to its favorable decay properties, the non-standard radionuclide 45Ti is a promising PET isotope for tumor imaging. Additionally, titanium complexes are widely used as anti-tumor agents and 45Ti could be used to study their in vivo distribution and metabolic fate. However, although 45Ti can be obtained using the 45Sc(p,n)45Ti nuclear reaction its facile production is offset by the high oxophilicity and hydrolytic instability of Ti4+ ions in aqueous solutions, which complicate recovery from the irradiated Sc matrix. Most available 45Ti recovery procedures rely on ion exchange chromatography or solvent extraction techniques which are time-consuming, produce large final elution volumes, or, in case of solvent extraction, cannot easily be automated. Thus a more widespread application of 45Ti for PET imaging has been hampered. Here, we describe a novel, solvent-free approach for recovery of 45Ti that involves formation of [45Ti]TiCl4 by heating of an irradiated Sc target in a gas stream of chlorine, followed by thermochromatographic separation of the volatile radiometal chloride from co-produced scandium chloride and trapping of [45Ti]TiCl4 in a glass vial at − 78 °C. The recovery of 45Ti amounted to 76 ± 5% (n = 5) and the radionuclidic purity was determined to be > 99%. After trapping, the [45Ti]TiCl4 could be directly used for 45Ti-radiolabeling, as demonstrated by the successful radiosynthesis of [45Ti][Ti(2,4-salan)].

scholarly journals Intein-mediated backbone cyclization of entolimod confers enhanced radioprotective activity in mouse models

2018 ◽  
Author(s):  
Bingyu Ye ◽  
Wenlong Shen ◽  
Minglei Shi ◽  
Yan Zhang ◽  
Cunshuan Xu ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Clinical Investigation ◽  
Affinity Purification ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Radioprotective Activity ◽  
Backbone Cyclization

Background. Entolimod is a Salmonella enterica flagellin derivate. Previous work has demonstrated that entolimod effectively protects mice and non-human primates from ionizing radiation. However, it caused a “flu-like” syndrome after radioprotective and anticancer clinical application, indicating some type of immunogenicity and toxicity. Cyclization is commonly used to improve the in vivo stability and activity of peptides and proteins. Methods. We designed and constructed cyclic entolimod using split Npu DnaE intein with almost 100% cyclization efficiency. We adopted different strategies to purify the linear and circular entolimod due to their different topologies. Results. After Ni-chelating affinity purification, the linear and circular entolimod were purified by size-exclusion and ion-exchange chromatography, respectively. Compared with linear entolimod, the circular entolimod showed significantly increased both the in vitro NF-κB signaling and in vivo radioprotective activity in mice. Discussions/Conclusions. Our data indicates that circular entolimod might be a good candidate for further clinical investigation.

scholarly journals Comparative study between the effects of hyaluronic acid and acid galactan purified from eggs of the mollusk Pomacea sp in wound healing

2004 ◽  
Vol 19 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Ana Katarina Menezes da Cruz ◽  
Wogelsanger Oliveira Pereira ◽  
Elizeu Antunes dos Santos ◽  
Maria Goretti Freire Carvalho ◽  
Aldo da Cunha Medeiros ◽  
...  
Keyword(s):  
Wound Healing ◽  
Small Intestine ◽  
Hyaluronic Acid ◽  
Wistar Rats ◽  
Saline Solution ◽  
Giant Cells ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Healing Tissue

PURPOSE: To compare the effect of hyaluronic acid (HA) and of AG on the healing of intestine wounds. METHODS: The semi-purified extract of the eggs of the mollusc was obtained by fractionation with ammonium sulfate and purification for ion-exchange chromatography. The obtained galactans were eluted in water (neutral galactan) and in 0.1 and 0.2M NaCl (acidic galactans). The in vivo study was performed with 45 "Wistar" rats, separated in three groups (n=15). Solutions containing HA 1%, GA 1% or saline solution 0,9%, was placed topically on the sutures of wounds in the small intestine of the rats. After 05, 10 and 21 days the animals were sacrificed and biopsy of the healing tissue was done. RESULTS: The hystologic grading was more significant for HA and AG groups when compared to the group C. AG stimulated the appearance of macrophages, giant cells and increase in the concentration of collagen in the area of the wound when compared to HA. CONCLUSION: The topical use of GA in intestinal wounds promoted the anticipation of events that are important in the wound healing.

Modified Pisano Method for Estimating Urinary Metanephrines

1973 ◽  
Vol 19 (6) ◽  
pp. 611-614 ◽  
Author(s):  
R N Gupta ◽  
D Price ◽  
P M Keane
Keyword(s):  
Solvent Extraction ◽  
Ion Exchange ◽  
Present Method ◽  
Age Groups ◽  
Internal Standard ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Normal Range ◽  
Related Compounds ◽  
Urinary Metanephrines

Abstract The Pisano method [Clin. Chim. Acta 5, 406 (1960)] for estimating urinary metanephrine, used in the screening of hypertensive persons for pheochromocytoma, has been modified by replacing ion-exchange chromatography with differential solvent extraction. An internal standard is incorporated to correct for procedural losses. Interference from some related compounds is negligible. Normal-range values obtained for various age groups by the present method compare well with those obtained by Pisano’s procedure, but are higher than values reported for more specific methods.

Isolation of Somatostatin (a Somatotropin Release Inhibiting Factor) of Ovine Hypothalamic Origin

1974 ◽  
Vol 52 (11) ◽  
pp. 1067-1072 ◽  
Author(s):  
P. Brazeau ◽  
W. Vale ◽  
R. Burgus ◽  
R. Guillemin
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Partition Chromatography ◽  
Inhibiting Factor ◽  
Layer Chromatography

Isolation of somatostatin, a tetradecapeptide of ovine origin inhibiting somatotropin secretion, is reported. About 490 000 hypothalamic fragments were submitted to alcohol–chloroform extraction, countercurrent distribution, ion-exchange chromatography, gel filtration, and partition chromatography. Of the 8.5 mg material thus obtained, 77% was accounted for by a peptide shown homogeneous by electrophoresis, thin-layer chromatography, and amino acid analysis. The peptide inhibits the secretion of radioimmunoassayable growth hormone at doses of ≥ 1.0 nM in vitro and 400 ng per rate in vivo.

scholarly journals The Copper Radioisotopes: A Systematic Review with Special Interest to 64Cu

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Artor Niccoli Asabella ◽  
Giuseppe Lucio Cascini ◽  
Corinna Altini ◽  
Domenico Paparella ◽  
Antonio Notaristefano ◽  
...  
Keyword(s):  
Iron Transport ◽  
Target Material ◽  
Chemical Separation ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Pathological Conditions ◽  
Important Trace Element ◽  
Cu Isotopes ◽  
Targeted Radiation Therapy

Copper (Cu) is an important trace element in humans; it plays a role as a cofactor for numerous enzymes and other proteins crucial for respiration, iron transport, metabolism, cell growth, and hemostasis. Natural copper comprises two stable isotopes, 63Cu and 65Cu, and 5 principal radioisotopes for molecular imaging applications (60Cu, 61Cu, 62Cu, and 64Cu) and in vivo targeted radiation therapy (64Cu and 67Cu). The two potential ways to produce Cu radioisotopes concern the use of the cyclotron or the reactor. A noncopper target is used to produce noncarrier-added Cu thanks to a chemical separation from the target material using ion exchange chromatography achieving a high amount of radioactivity with the lowest possible amount of nonradioactive isotopes. In recent years, Cu isotopes have been linked to antibodies, proteins, peptides, and nanoparticles for preclinical and clinical research; pathological conditions that influence Cu metabolism such as Menkes syndrome, Wilson disease, inflammation, tumor growth, metastasis, angiogenesis, and drug resistance have been studied. We aim to discuss all Cu radioisotopes application focusing on 64Cu and in particular its form 64CuCl2 that seems to be the most promising for its half-life, radiation emissions, and stability with chelators, allowing several applications in oncological and nononcological fields.

scholarly journals Biosynthesis of proteins by human gastric mucosa in vitro

1987 ◽  
Vol 242 (2) ◽  
pp. 339-346 ◽  
Author(s):  
M Spohn ◽  
I McColl
Keyword(s):  
Gastric Mucosa ◽  
Polyacrylamide Gel Electrophoresis ◽  
Deae Cellulose ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Human Gastric Mucosa ◽  
Tissue Incorporation ◽  
Mucus Glycoproteins

Incorporation of L-[U-14C]leucine and of D[U-14C]glucose into proteins of fresh human gastric mucosa in vitro was studied after incubation of homogenized tissue and of intact mucosal pieces. CsCl centrifugation was used to separate high-density mucus glycoproteins from other mucosal proteins, and the macromolecular nature of radioactive mucosal glycoprotein fractions was confirmed by SDS/polyacrylamide-gel electrophoresis and autoradiography of the polyacrylamide gels. In all experiments a substantial proportion of total incorporated radioactivity was associated with gastric-mucosal glycoprotein fractions (CsCl fraction L3), indicating their biosynthesis. Radioactivity of these fractions was shown to co-chromatograph with carbohydrates when fractionated either directly or after reduction and alkylation (1) Sephadex G-200 chromatography in the excluded fractions and (2) by DEAE-cellulose ion-exchange chromatography. On incubation of intact mucosa, the major portion of radioactivity associated with the glycoprotein fractions of both leucine- and glucose-labelled specimens was secreted into the mucosal media during the course of the experiment. It is suggested that biosynthesis of mucus in vivo by gastric mucosa may be associated with rapid secretion of the synthesized macromolecules into the lumen of the stomach and that investigations of the metabolic processes within the mucosa should consider the products of secretion of the tissue. Incorporation of L-[U-14C]leucine implies biosynthesis of the polypeptide components of the macromolecules.

scholarly journals Keratin incorporation into intermediate filament networks is a rapid process.

1991 ◽  
Vol 113 (4) ◽  
pp. 843-855 ◽  
Author(s):  
R K Miller ◽  
K Vikstrom ◽  
R D Goldman
Keyword(s):  
Ion Exchange ◽  
Intermediate Filament ◽  
Immunofluorescence Microscopy ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Type I ◽  
Type Ii ◽  
Filament Networks ◽  
Cytoskeletal Elements

The properties of keratin-containing intermediate filament (IF) networks in vivo were studied following the microinjection of biotinylated keratin. Keratin-IFs were biotinylated, disassembled, and separated into type I and type II proteins by ion exchange chromatography. Recombination of these derivatized type I and type II keratins resulted in the formation of 10-nm diameter IF. The type I keratins were microinjected into epithelial cells and observed by immunofluorescence microscopy. Biotin-rich spots were found throughout the cytoplasm at 15-20 min after injection. Short biotinylated fibrous structures were seen at 30-45 min after injection, most of which colocalized with the endogenous bundles of IF (tono-filaments). By 1 1/2 to 2 h after microinjection, extensive biotinylated keratin IF-like networks were evident. These were highly coincident with the endogenous tonofilaments throughout the cell, including those at desmosomal junctions. These results suggest the existence of a relatively rapid subunit incorporation mechanism using numerous sites along the length of the endogenous tonofilament bundles. These observations support the idea that keratin-IFs are dynamic cytoskeletal elements.

IODOPEPTIDES FROM HUMAN THYROGLOBULIN

1977 ◽  
Vol 85 (4) ◽  
pp. 769-780 ◽  
Author(s):  
Lubomir J. Valenta ◽  
A. Donny Strosberg ◽  
Vera Valenta ◽  
Jean-Claude Jaton
Keyword(s):  
Ion Exchange ◽  
Peptide Mapping ◽  
Thyroid Tissue ◽  
Iodine Content ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Small Peptides ◽  
Thyroid Glands ◽  
High Voltage Electrophoresis

ABSTRACT Human thyroglobulin labelled in vivo by 125I was purified from eight different thyroid glands including normal thyroid tissue, thyrotoxic goitre and euthyroid multinodular goitre. The purified protein was cleaved with cyanogen bromide (CNBr) and the resulting peptides were separated by column chromatography and ion exchange chromatography. Reproducible elution profiles of both protein and iodine were obtained. However, the distribution of iodine depended on the iodine content of the intact thyroglobulin. Small CNBr peptides seemed to be preferentially iodinated, but with a limited capacity. With higher degrees of iodination, larger peptides became richer in iodine. This suggests sequential iodination of the thyroglobulin molecule. The mixture of small peptides was digested by trypsin. Two iodopeptides were identified in this material by peptide mapping and they had identical migration in thyroglobulins of different origin. One of them was purified by ion exchange chromatography and high voltage electrophoresis. Analogous amino acid composition was obtained for the iodopeptide purified from two different thyroglobulins. The data indicates that thyroglobulin iodination occurs in specific portions of the polypeptide chain and probably in a sequential manner.

scholarly journals Characterization of phospholipid methylation in rat brain myelin

1995 ◽  
Vol 307 (1) ◽  
pp. 239-244 ◽  
Author(s):  
V Tsvetnitsky ◽  
L Auchi ◽  
A Nicolaou ◽  
W A Gibbons
Keyword(s):  
Rat Brain ◽  
Affinity Purification ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Methyl Transferase ◽  
Sds Page ◽  
Triton X ◽  
Predominant Product

Highly purified rat brain myelin was solubilized in Triton X-100 and myelin phospholipid N-methyltransferase was characterized. The enzyme activities were separated by isoelectric focusing and ion-exchange chromatography. The phospholipid methyl-transferase has shown at least four peaks of activity with pIapp. values of 4.5, 5.2, 6.2 and 8.4. After affinity purification each of these activities revealed a close set of bands of approx. 65 kDa on SDS/PAGE. These data together with those from preparative SDS/PAGE separations suggested that rat brain myelin contains three acidic and at least one basic phospholipid-methylating isoenzymes and that the major isoenzyme in each case is approx. 65 kDa in size. While the predominant product of the reaction catalysed by all detected isoforms was monomethylated phosphatidylethanolamine, the least acidic isoform (pIapp. 6.2) also formed about 20% phosphatidylcholine, suggesting that these isoenzymes may play different roles in vivo.

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