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Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development. Main body: This selection of highlights provides commentary on 21 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first-in-human application of novel radiopharmaceuticals. Conclusion: Trends in radiochemistry and radiopharmacy are highlighted. Hot topics cover the entire scope of EJNMMI Radiopharmacy and Chemistry, demonstrating the progress in the research field in many aspects. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWCNTs) were modified noncovalently with cetyltrimethylammonium bromide. The Nb/Nb5Si3 in situ composite material that was strengthened with MWCNTs was prepared by SPS. The effect of MWCNT content on the microstructure and properties of Nb/Nb5Si3 in situ composites was investigated. The results showed that the composites consisted of Nb, α-Nb5Si3 and β-Nb5Si3 phases. With the addition of over 2 wt% MWCNT, a new Nb4C3 phase was formed in the composites. The properties of the Nb/Nb5Si3 in situ composites were affected by MWCNT addition. The relative density, Vickers hardness and fracture toughness increased with increasing MWCNT addition. When the MWCNT addition was 2 wt%, the relative density and Vickers hardness reached a maximum and increased by ~ 1.4% and ~ 18%, respectively (relative to 0 wt% MWCNT addition). When the MWCNT content exceeded 2 wt%, the relative density and the Vickers hardness decreased. However, the fracture toughness of the Nb/Nb5Si3 composites with 3 wt% MWCNTs reached a maximum (an increase of ~ 68% relative to 0 wt% MWCNT addition). Scanning electron micrographs of the fractography showed brittle cleavage and partial intercrystalline composite fracture. The composite toughening mechanisms arose mainly because of MWCNT removal and bridging. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is the most common brain malignancy. Long non-coding RNAs (lncRNAs) are aberrantly expressed in many cancers and are involved in their cell proliferation, apoptosis, angiogenesis, and invasion. The functional roles of lncRNAs in GBM are less known. We analyzed a cohort of exon microarray datasets from The Cancer Genome Atlas. The differently expressed lncRNAs and mRNA were subjected to construct lncRNA-mRNA co-expression network. Probable functions for lncRNAs were predicted according to lncRNA-mRNA network and genomic adjacency by GO and pathway analysis. The expression of lncRNAs and mRNAs in GBM tissues versus normal brain tissues was examined by quantitative reverse transcription polymerase chain reaction. The 398 lncRNAs and 1995 mRNAs were identified as distinctively expressed in GBM. Probable functional roles for 98 lncRNAs were involved in 30 pathways and 32 gene functions related to tumorigenesis, development, and metastasis. The identified sets of key lncRNAs specific to GBM were subsequently verified by experiment in GBM tissues. Our reports predict the biological functions of a multitude of lncRNAs in GBM that could be potential diagnostic and prognostic biomarkers as well as therapeutic targets. Moreover, our research provides a road map for the identification and analysis of lncRNAs in tumors. [ABSTRACT FROM AUTHOR]

For the development of new ligands as potential imaging agents for the serotonin transporter (SERT), a series of diphenyl ether derivatives have been synthesized, characterized, and evaluated for their in vitro binding affinities to the SERT. Among the above compounds, 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-bromobenzenamine (15) and 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-iodobenzene amine (16) show high binding affinities for the SERT with K i values of 0.28 and 0.20 nmol·L−1, respectively. They can be further labeled with carbon-11, fluorine-18, iodine-123 or bromine-76, and evaluated as useful imaging agents for the SERT. Moreover, the study of the structure-activity relationship (SAR) provides some useful information for the future design of new ligands. [ABSTRACT FROM AUTHOR]

A novel 99mTc labeled complex, [N-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V) oxide (PPPE-MAMA’-99mTcO) ([ 99m Tc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA’-ReO)( Re-2) has been prepared and characterized. In vitro competition binding assays show moderate affinity of Re-2 towards σ1 and σ2 receptors with Ki values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after i.v. injection indicate the accumulation of [ 99m Tc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [ 99m Tc]-2 has been inhibited at 20 h after co-injection of [ 99m Tc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [ 99m Tc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post i.v. injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results suggest that [ 99m Tc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [ 99m Tc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors. [ABSTRACT FROM AUTHOR]

Presents an analysis of electrostatic hydration free energies of the isomers of the 99mTc-BAT and 99mTc-DADT complexes carried out using the computer simulation technique. Description of the results, which show that not only a correlation exists between the logarithm of the brain uptake and the electrostatic hydration free energy for the isomers of 99mTc-brain radiopharmaceuticals, but also a linear relationship exists between the logarithm of the ratio of the brain uptake of the syn isomer to that of the anti one and the difference between the electrostatic hydration free energy of the syn-isomer and that of the anti one; Investigation on the important factors influencing the brain uptakes of 99mTc-radiopharmaceuticals and the reasons of the different biodistribution of the isomers of the 99mTc-complexes, explored at the molecular level; Assertion that the results may provide a reference for the rational drug design of brain imaging agents.