Nock, BCordopatis, PMaina, TNikolopoulou, AChiotellis, EMaintas, DSotiriou, PLoudos, GDemotate is a new tetraamine-functionalised [Tyr(3)]octreotate derivative that binds technetium-99m with a high efficiency under mild conditions. The resulting radioligand, [Tc-99m]Demotate, forms in a high purity and is stable for at least 6 h after labelling. The affinity of the unlabelled peptide for somatostatin receptors is high (IC50=0.13 nM) and comparable to that of [Tyr(3)]octreotate or [Tyr3]octreotide, as demonstrated by competition binding experiments in rat brain cortex or AR42J cell membrane preparations. An equally very high affinity (K-d=0.07 nM) was exhibited by [Tc-99m/Tc-99g]Demotate during saturation binding experiments using rat brain cortex membrane homogenates. The radioligand resisted hydrolytic degradation in mouse plasma and was excreted intact in mouse urine. In vivo, [Tc-99m]Demotate cleared very rapidly from non-target tissues into the bladder via the kidneys, while radioactivity uptake in target organs was very high. In mice bearing the experimental AR42J tumour, [99mTc]Demotate demonstrated a very high tumour uptake at I h p.i. (25%ID/g) that remained high (20%ID/g) at 4 h p.i. This uptake could be effectively blocked by co-injection of a high dose of [Tyr3]octreotate together with the radioligand. High-quality planar and single-photon emission tomographic images were acquired 1 h after injection of [Tc-99m]Demotate in tumour-bearing mice, illustrating the excellent properties of this agent for somatostatin receptor tumour imaging.http://hdl.handle.net/123456789/265371619-7070742753629ISI:000176324700005engSPRINGER-VERLAGEUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGINGsomatostatin receptorDIAGNOSIStetraamine chelatorSCINTIGRAPHYtumour imagingTUMORSTc-99mIN-VITRORADIOPHARMACEUTICALSMETABOLISMAFFINITY[Tyr(3)]octreotateRADIOTHERAPYDERIVATIVESBINDING PEPTIDES[Tc-99m]demotate, a new Tc-99m-based [Tyr(3)]octreotate analogue for the detection of somatostatin receptor-positive tumours: synthesis and preclinical resultsjournalArticle2002Ραδιολογία, Πυρηνική ιατρική και ΑπεικονιστικήRadiology, Nuclear Medicine and Imagingisi - Radiology, Nuclear Medicine & Medical Imaging covers resources on radiation research in biology and biophysics. Resources in this category focus on interventional radiology, investigative radiology, neuroradiology, radiotherapy, and oncology. Nuclear Medicine resources are concerned with the diagnostic, therapeutic, and investigative use of radionuclides. Medical Imaging resources are concerned with computerized medical imaging and graphics.Δημοσίευση σε περιοδικόPublication in journalΕπιστημονικό άρθροScientific articleΕθνικό Μετσόβιο ΠολυτεχνείοGreek Aggregator OpenArchives.gr | National Documentation Centre (EKT)other