Synthesis and Evaluation of Three (18)F-Labeled Aminophenylbenzothiazoles as Amyloid Imaging Agents

We have developed three fluorine-18 labeled 6-(methyl)amino-2-(4'-fluorophenyl)-1,3-benzothiazoles, which display high in vitro binding affinity for human amyloid beta plaques (K(i) < or = 10 nM). The radiolabeled probes were synthesized by aromatic nucleophilic substitution of the corresponding nitro precursor with (18)F-fluoride, followed by deprotection of the BOC group if required. Determination of the octanol/water partition coefficient, biodistribution studies in mice, and in vivo muPET studies in rats and a rhesus monkey showed that initial brain uptake was high and brain washout was fast in normal animals. Radiometabolites were quantified in plasma and brain of mice and in monkey plasma using HPLC. Of the tested compounds, [(18)F]2 (6-amino-2-(4'-[(18)F]fluorophenyl)-1,3-benzothiazole) shows the most favorable brain kinetics in mice, rats, and a monkey. Its polar plasma radiometabolites do not cross the blood-brain barrier. The preliminary results strongly suggest that this new fluorinated compound is a promising candidate as a PET brain amyloid imaging agent.status: publishe

Slowing Down of Gamma Photons

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Principles of stroboscopic detection of nuclear forward-scattered synchrotron radiation

The basic principles of stroboscopic detection of nuclear resonant forward-scattered synchrotron radiation are discussed. It is explained how the experiment can be configured in such a way that energy-resolved spectra with a straightforward interpretation are obtained. The theory is supported by a set of experimental spectra on the single-line compound potassium ferrocyanide trihydrate. Further, it is shown that a stroboscopic measurement is equivalent to an interferometer experiment. Finally, a comparison of stroboscopic detection and other Mössbauer techniques is given.SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Induced transparency for gamma radiation via nuclear level mixing

A significant reduction of absorption of single gamma photons has been observed using the Mössbauer spectra of 57Fe in a FeCO3 crystal. The absorption deficit can be ascribed to partially destructive interference for absorption because of two indistinguishable absorption paths. The necessary coherence is created by means of level mixing produced by a suitable combination of a magnetic dipole and electric quadrupole interaction.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Isomer shift determination in Eu compounds using stroboscopic detection of synchrotron radiation

The first application of stroboscopic detection of nuclear resonant scattering with synchrotron radiation on Eu-151 is reported. It is shown that stroboscopic detection is a useful technique for the determination of isomer shifts and this is confirmed by a measurement of the isomer shift of Eu-151 in EuPd2Si2 at pressures ranging from ambient pressure to 5 GPa. The results are compared with previous measurements

Impact of cholinergic tone on the binding of PET tracer [11C] MK-6884, a positive allosteric modulator of M4 acetylcholine receptor in monkeys and healthy elderly volunteers

edition: Abstractbook of EUFEMED meeting 2019: The changing landscape of early medicines development: be preparedstatus: publishe