A new (SS)(P) coordination set based on the concurrent use of a dithiocarbamate and a functionalised phosphane is reported. The (SS)(P) fashion is achieved by applying the [2+1] mixed-ligand concept and makes it possible to obtain stable rhenium tricarbonyl complexes without employing tripodal bifunctional chelating agents (BFCAs

Synthesis and some applications of a novel [(18)F]-fluorinated prosthetic group based on the promising sultone radiochemistry and suitable for the labelling of amine-containing (bio)chemical compounds are described. The combined sequential use of two easy and efficient conjugation reactions namely the fluoride ring-opening of a 1,3-propanesultone moiety and the aminolysis of an N-hydroxysuccinimidyl ester is the key component of this original radiolabelling strategy. The mild reaction conditions and the release of a free sulfonic acid moiety as a result of the [(18)F]-induced sultone ring-opening reaction, both make this [(18)F]-conjugation method suitable for the radiofluorination of fragile and hydrophobic biomolecules and fluorophores, particularly by making the separation of the targeted [(18)F]-tagged sulfonated compound from its starting precursor easier and thus faster. The ability of this unusual prosthetic group to readily introduce the radioisotope within complex (bio)molecular architectures has been demonstrated by (1) the preparation of the first [(18)F]-labelled cyanine 5.5 (Cy 5.5) dye, a suitable precursor for the construction of hybrid positron emission tomography/near-infrared fluorescence (PET/NIRF) imaging probes and (2) the radiolabelling of a biologically relevant peptide bearing a single lysine residue.

Positron emission tomography (PET)-computed tomography (CT) using [18F]-fluorodeoxyglucose (FDG) (FDG-PET/CT) is a valuable method for initial staging and follow up of patients with alveolar echinococcosis (AE). However, the cells responsible for FDG uptake have not been clearly identified. The main goal of our study was to evaluate the uptake of PET tracers by the cells involved in the host-parasite reaction around AE lesions as the first step to develop a specific PET tracer that would allow direct assessment of parasite viability in AE. Candidate molecules ([18F]-fluorotyrosine (FET), [18F]-fluorothymidine (FLT), and [18F]-fluorometylcholine (FMC), were compared to FDG by in vitro studies on human leukocytes and parasite vesicles. Our results confirmed that FDG was mainly consumed by immune cells and showed that FLT was the best candidate tracer for parasite metabolism. Indeed, parasite cells exhibited high uptake of FLT. We also performed PET/CT scans in mice infected intraperitoneally with E. multilocularis metacestodes. PET images showed no FDG or FLT uptake in parasitic lesions. This preliminary study assessed the metabolic activity of human leukocytes and AE cells using radiolabeling. Future studies could develop a specific PET tracer for AE lesions to improve lesion detection and echinococcosis treatment in patients. Our results demonstrated that a new animal model is needed for preclinical PET imaging to better mimic human hepatic and/or periparasitic metabolism.

SummaryPaclitaxel, an anti-tumour drug, shows good results against breast and ovarian cancer. However, its therapeutic response is associated with toxic side-effects caused by the agent used to dissolve it. Recently paclitaxel was linked to the linear polysaccharide hyaluronic acid (HA), showing good solubility, stabilization, localization and a reduction of cytotoxic side-effects.To study potential therapeutic applications, HA-paclitaxel bioconjugate (ONCO-FID-P) was labelled with 99m Tc by the addition of 99m Tc-pertechnetate, SnCl 2 and sodium gluconate. The reaction mixture was incubated for 90 min at 658C and purified by size exclusion chromatography. The obtained 99mTc-ONCOFID-P had 100% radiochemical purity and was stable in a phosphate buffer dilution 1:100 for 6 h at 378C. Tc-ONCOFID-P bioavailability studies were carried out in healthy mice using four different administration pathways. The analysis showed that after intravenous administration more than 80% of the injected radiopharmaceutical was found in liver and spleen. Intraperitoneal, intravesical and oral administrations showed that all the 99m Tc-ONCOFID-P remained at the administration site.These results demonstrate that ONCOFID-P administered intravenously could be used for liver metastasis therapy due to its high physiological and receptor-specific liver uptake, while intravesical, intraperitoneal and oral administration of ONCOFID-P could be used for local treatment of superficial cancers.

The synthesis, the characterization and the X-ray crystal structure of a novel tantalum(v) complex tris(1,2-dimethyl-3-hydroxy-4(1H)-pyridone)oxotantalum(v) [TaO(C7H8O2N)3] 1 is reported. Starting from the tantalum pentaethoxide a two-step reaction was carried out observing rigorous anhydrous conditions in methanol in the first step, while the insertion of the oxo group was achieved using water as oxygen donor in the second step. X-Ray diffraction analysis of a crystal of 1 obtained upon evaporation of an aqueous solution shows a seven-coordinate monomeric complex containing the [Ta=O]3+ core in the triclinic space group P1, a = 7.282(3), b = 14.055(5), c = 16.987(6) A, alpha = 65.704(5), beta = 89.155(6), gamma = 75.270(6) degrees, V = 1525(1)A3, Z = 2. Spectroscopic investigation reveals that the complex is highly soluble and stable in water at physiological pH values; as a consequence the complex may represent a potential candidate for the development of new studies on aqueous tantalum(v) chemistry for radiopharmaceutical applications.