Search results for "VITRO"
showing 10 items of 2786 documents
[68Ga]Ga-THP-Pam: A Bisphosphonate PET Tracer with Facile Radiolabeling and Broad Calcium Mineral Affinity
2020
Calcium minerals such as hydroxyapatite (HAp) can be detected non-invasively in vivo using nuclear imaging agents such as [18F]NaF (available from cyclotrons), for positron emission tomography (PET) and 99mTc-radiolabelled bisphosphonates (BP; available from 99mTc generators for single photon emission computed tomography (SPECT) or scintigraphy). These two types of imaging agents allow detection of bone metastases (based on the presence of HAp) and vascular calcification lesions (that contain HAp and other calcium minerals). With the aim of developing a cyclotron-independent PET radiotracer for these lesions, with broad calcium mineral affinity and simple one-step radiolabelling, we develop…
MANOTA: a promising bifunctional chelating agent for copper-64 immunoPET
2017
International audience; Improved bifunctional chelating agents (BFC) are required for copper-64 radiolabelling of monoclonal antibodies (mAbs) under mild conditions to yield stable, target-specific imaging agents. Four different bifunctional chelating agents (BFC) were evaluated for Fab (Fragment antigen binding) conjugation and radiolabelling with copper-64. Two DOTA- (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and two NOTA- (1,4,7-triazacyclononane-1,4,7-triacetic acid) derivatives bearing a p-benzyl-isothiocyanate group were conjugated to Fab-trastuzumab - which targets the HER2/neu receptor - and the average number of chelators attached ranged from 2.4 to 4.3 macrocycles …
Bisphosphonate-polyaspartamide conjugates as bone targeted drug delivery systems.
2015
Poly-hydroxy-aspartamide was used as a backbone to synthesize bisphosphonate derivatives thus achieving macromolecular carriers to be potentially used as targeting agents for bone drug delivery. Molecules bearing bisphosphonate groups, such as aminobisphosphonate (ABP) and neridronate (NRD), have been conjugated to polyaspartamide (α,β-poly(N-2-hydroxyethyl)-dl-aspartamide, PHEA), with or without a spacer (succinic acid or 6-aminocaproic acid) thus obtaining PHEA-succinate-ABP and PHEA-caproylcarbamate-ABP and PHEA-ABP and PHEA-NRD, respectively. Bisphosphonate-polymer conjugates were physico-chemically characterized using size exclusion chromatography and 1H-NMR; and their in vitro and e…
Synthesis of 131I-labeled glucose-conjugated inhibitors of O6-methylguanine-DNA methyltransferase (MGMT) and comparison with nonconjugated inhibitors…
2006
O 6 -Substituted guanine derivatives are powerful agents used for tumor cell sensitization by inhibition of the DNA repair enzyme O 6 -methylguanine-DNA methyltransferase (MGMT). To provide targeted accumulation of MGMT inhibitors in tumor tissue as well as tools for in vivo imaging, we synthesized iodinated C 8 -alkyl-linked glucose conjugates of 2-amino-6-(5-iodothenyl)-9H-purine (O 6 -(5-iodothenyl) guanine, ITG) and 2-amino-6-(3-iodobenzyloxy)-9H-purine (O 6 -(5-iodobenzyl) guanine, IBG). These compounds have MGMT inhibitor constants (IC 5 0 values) of 0.8 and 0.45 μM for ITGG and IBGG, respectively, as determined in HeLa S3 cells after 2-h incubation with inhibitor. To substantiate tha…
Unraveling the In Vivo Protein Corona
2021
Understanding the behavior of nanoparticles upon contact with a physiological environment is of urgent need in order to improve their properties for a successful therapeutic application. Most commonly, the interaction of nanoparticles with plasma proteins are studied under in vitro conditions. However, this has been shown to not reflect the complex situation after in vivo administration. Therefore, here we focused on the investigation of magnetic nanoparticles with blood proteins under in vivo conditions. Importantly, we observed a radically different proteome in vivo in comparison to the in vitro situation underlining the significance of in vivo protein corona studies. Next to this, we fou…
Novel heterobimetallic radiotheranostic: preparation, activity, and biodistribution.
2014
A novel Ru(II) (arene) theranostic complex is presented. It is based on a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid macrocycle bearing a triarylphosphine and can be tracked in vivo by using the γ emission of (153) Sm atoms. Notably, the heteroditopic ligand can be selectively metalated with ruthenium at the phosphorus atom despite the presence of other functionalities that are prone to metal coordination. Subsequent labeling with radionuclides such as (153) Sm can then be performed easily. The resulting heterobimetallic complex exhibits favorable solubility and stability properties in biologically relevant media. It also shows in vitro cytotoxicity in line with that expected …
New evidence for the multiplicity of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I.
2000
Determination of the number of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a controversial question with a direct implication for elaborating a suitable model to explain the bioenergetic mechanism of this complicated enzyme. We have used combinations of both selective inhibitors and common ubiquinone-like substrates to demonstrate the multiplicity of the reaction centers in the complex I in contrast with competition studies that have suggested the existence of a unique binding site for ubiquinone. Our results provide new evidence for the existence of at least two freely exchangeable ubiquinone-binding sites with different specif…
Neural Crest-Derived Chondrocytes Isolation for Tissue Engineering in Regenerative Medicine
2020
Chondrocyte transplantation has been successfully tested and proposed as a clinical procedure aiming to repair articular cartilage defects. However, the isolation of chondrocytes and the optimization of the enzymatic digestion process, as well as their successful in vitro expansion, remain the main challenges in cartilage tissue engineering. In order to address these issues, we investigated the performance of recombinant collagenases in tissue dissociation assays with the aim of isolating chondrocytes from bovine nasal cartilage in order to establish the optimal enzyme blend to ensure the best outcomes of the overall procedure. We show, for the first time, that collagenase H activity alone …
Gangliosides and sialic acid effects upon newborn pathogenic bacteria adhesion: An in vitro study
2012
The effect of the main gangliosides (GM(1), GM(3), GD(3)) and free sialic acid (Neu5Ac) upon the adhesion of pathogenic bacteria implicated in infant diarrhoea is assessed in vitro using the Caco-2 cell line. Concentrations of the bioactive compounds found in the bioaccessible (soluble) fraction of infant formula and human milk are employed. Bacterial adhesion behaviour included enterotoxigenic Escherichia coli (ETEC), enteropathogenic E.coli (EPEC), Listeria monocytogenes, Salmonella entericaserovartyphi, Shigella sonnei, Campylobacter jejuni and Helicobacter pylori. Three different approaches were assayed: pre-incubation of bacteria and compounds before addition to cells (competition); pr…
Electrochemical probe for the monitoring of DNA-protein interactions.
2010
Self-assembly of thiol-terminated oligonucleotides on gold substrates provides a convenient way for DNA-functionalized surfaces. Here we describe the development of an electrochemical assay for the detection of DNA-protein interactions based on the modification of the electrochemical response of methylene blue (MB) intercalated in the DNA strands. Using a functionalized electrode with double stranded DNA carrying T3 RNA polymerase binding sequence, we show a substantial attenuation of the current upon the DNA-protein interaction. Moreover, a Langmuir binding isotherm for T3 RNA polymerase (T3 Pol) gives a dissociation constant K(D) equal to 0.46+/-0.23 microM. Such value is 100 times lower …