Search results for "RADIOCHEMISTRY"
showing 10 items of 273 documents
Dendrimer-coated magnetic particles for radionuclide separation
2005
Magnetic particles were synthesised for radionuclide removal from nuclear wastes by magnetic separation. Dendrimers with terminal amino groups attached to the particle surface were used to bind chelating groups for lanthanides and actinides. This led to a 50–400-fold increase of the distribution coefficients for europium and americium in comparison to the reference particles without the dendrimers. Back-extraction studies have demonstrated the possibility of multiple particle recycling.
Beta-delayed proton emission observed in new lanthanide isotopes
1984
The following new, beta-delayed proton emitters have been observed at the on-line isotope separator OASIS:120La (2.8±2s),122La (8.7±7s),123Ce (3.8±2s),141Dy (1.0±2s),141Gd, and143Dy (3.2±6s). Z-identification was achieved through observation of characteristic x-rays in coincidence with protons.
Dual Labeling of Lipopolysaccharides for SPECT-CT Imaging and Fluorescence Microscopy.
2013
International audience; : Lipopolysaccharides (LPS) or endotoxins are amphipathic, pro-inflammatory components of the outer membrane of Gram-negative bacteria. In the host, LPS can trigger a systemic inflammatory response syndrome. To bring insight into in vivo tissue distribution and cellular uptake of LPS, dual labeling was performed with a bimodal molecular probe designed for fluorescence and nuclear imaging. LPS were labeled with DOTA-Bodipy-NCS, and pro-inflammatory properties were controlled after each labeling step. LPS were then radiolabeled with (111)In and subsequently injected intravenously into wild-type, C57B16 mice, and their in vivo behavior was followed by single photon emis…
The impact of conventional and heavy ion irradiation on tumor cell migration in vitro.
2007
The influence of X-ray and (12)C heavy ion irradiation on tumor cell migration and of beta(3) and beta(1) integrin expression was investigated.Two different tumor cell lines (U87 glioma and HCT116 colon carcinoma cells) were irradiated with 1, 3, or 10 Gy X-rays or (12)C heavy ions. 24 h after irradiation a standardized Boyden Chamber assay for migration analysis was performed and cells were lysed for Western blotting.Radiation-induced influences were cell line- and radiation type-dependent. X-rays decreased HCT116 migration at higher doses and appear to increase U87 migration after 3 Gy. Heavy ions decreased migration of both cell lines dose-dependently. A trend of increased beta(3) and be…
Bifunctional Gallium-68 Chelators: Past, Present, and Future
2016
This article reviews the development of bifunctional chelates for synthesising (68)Ga radiopharmaceuticals. It structures the chelates into groups of macrocycles, nonmacrocycles, and chimeric derivatives. The most relevant bifunctional chelates are discussed in chelate structure, parameters of (68)Ga-labeling, and stability of the (68)Ga-chelate complexes. Furthermore those derivatives are included, where (67)Ga was applied instead of (68)Ga. A particular feature discussed is the ability of certain bifunctional chelate structures to function in kit-type preparation of the (68)Ga radiopharmaceuticals. Currently, nonmacrocyclic and chimeric derivates attract particular attention such as THP-d…
Synthesis and evaluation in rats of the dopamine D2/3 receptor agonist 18F-AMC20 as a potential radioligand for PET
2015
Dopamine D2/3 receptor (D2/3R) agonist PET tracers are better suited for the imaging of synaptic dopaminergic neurotransmission than D2/3R antagonists and may also offer the opportunity to study in vivo the high-affinity state of D2/3R (D2/3RHigh). With the aim to develop 18F-labeled D2/3R agonists suitable for widespread clinical application, we report here on the synthesis and in vitro and in vivo evaluation of a D2/3R agonist ligand from the aminomethyl chromane (AMC) class-(R)-2-[(4- 18Fluorobenzylamino)methyl]chroman-7-ol (18F-AMC20). Methods: In vitro affinities of AMC20 toward dopaminergic receptor subtypes were measured in membrane homogenates prepared from HEK293 cells expressing h…
18F-labeling and evaluation of novel MDL 100907 derivatives as potential 5-HT2A antagonists for molecular imaging.
2009
Abstract Introduction The serotonergic system, especially the 5-HT2A receptor, is involved in various diseases and conditions. It is a very interesting target for medicinal applications. Methods Two novel 5-HT2A tracers, namely, [ 18 F]DD-1 and the enantiomeric pure ( R )-[ 18 F]MH.MZ, were radiolabeled by 18 F-fluoroalkylation of the corresponding desmethyl analogue. In vitro binding autoradiography on rat brain slices was performed to test the affinity and selectivity of these tracers. Moreover, first μPET experiments of ( R )-[ 18 F]MH.MZ were carried out in Sprague-Dawley rats. Results [ 18 F]DD-1 ( K i =3.23 nM) and ( R )-[ 18 F]MH.MZ ( K i =0.72 nM) were 18 F-fluoroalkylated by the se…
68Ga-BPAMD: PET-imaging of bone metastases with a generator based positron emitter
2012
Abstract Purpose Bone metastases are a serious aggravation for patients suffering from cancer. Therefore, early recognition of bone metastases is of great interest for further treatment of patients. Bisphosphonates are widely used for scintigraphy of bone lesions with 99m Tc. Using the 68 Ge/ 68 Ga generator together with a macroyclic bisphosphonate a comparable PET-tracer comes into focus. Procedures The bisphosphonate DOTA-conjugated ligand BPAMD was labelled with 68 Ga. [ 68 Ga]BPAMD was evaluated in vitro concerning binding to hydroxyapatite and stability. The tracer's in vivo accumulation was determined on healthy rats and bone metastases bearing animals by μ-PET. Results BPAMD was lab…
Radiolabelling and preliminary evaluation of 68Ga-tetrapyrrole derivatives as potential tracers for PET
2013
article i nfo Tetrapyrroles are multisided natural products which are of relevance in clinical medicine. Owing to their specific accumulation in tumour tissue, porphyrins, metalloporphyrins and chlorins have been used as in photodynamic therapy and optical imaging. Moreover, their specific uptake into inflammatory atheromatous plaques via LDL endocytosis has been reported. The present study is concerned with the synthesis of 68 Ga labelled porphyrin derivatives and an in vitro assessment of the utility of radiotracers in positron emission tomography. A set of five porphyrin derivatives were labelled using 68 Ga from a commercially obtained radionuclide generator. Dedicated post-processing o…
In vivo biodistribution of amino-functionalized ceria nanoparticles in rats using positron emission tomography.
2012
A variety of nanoparticles have been proposed for several biomedical applications. To gauge the therapeutic potential of these nanoparticles, in vivo biodistribution is essential and mandatory. In the present study, ceria nanoparticles (5 nm average particle size) were labeled with F-18 to study their in vivo biodistribution in rats by positron emission tomography (PET). The F-18 isotope was anchored by reaction of N-succinimidyl 4-[F-18]fluorobenzoate (F-18-SFB) with a modified nanoparticle surface obtained by silylation with 3-aminopropylsilyl. Radiolabeled ceria nanoparticles accumulated mainly in lungs, spleen, and liver. Metabolic products of the radiolabeled nanoparticulate material w…