Autoradiography of Intracerebral Tumours in the Chick Embryo Model: A Feasibility Study Using Different PET Tracers.

Purpose: In addition to rodent models, the chick embryo model has gained attention for radiotracer evaluation. Previous studies have investigated tumours on the chorioallantoic membrane (CAM), but its value for radiotracer imaging of intracerebral tumours has yet to be demonstrated.

Procedures: Human U87 glioblastoma cells and U87-IDH1 mutant glioma cells were implanted into the brains of chick embryos at developmental day 5.

[F]R91150: Improved radiosynthesis and in vivo evaluation as imaging probe for 5-HT receptors.

Serotonergic 5-HT receptors in the cortex and other forebrain structures have been linked to cognitive, emotional and memory processes. In addition, dysfunction or altered expression of these receptors is associated with neuropsychiatric and neurodegenerative disorders. [F]R91150 is a candidate radiotracer for positron emission tomography (PET) imaging of 5-HT receptors, which showed promising properties in in vitro studies.

Autophagy regulator ATG5 preserves cerebellar function by safeguarding its glycolytic activity.

Dysfunctions in autophagy, a cellular mechanism for breaking down components within lysosomes, often lead to neurodegeneration. The specific mechanisms underlying neuronal vulnerability due to autophagy dysfunction remain elusive. Here we show that autophagy contributes to cerebellar Purkinje cell (PC) survival by safeguarding their glycolytic activity.

Do you know your PSMA-tracer? Variability in the biodistribution of different PSMA ligands and its potential impact on defining PSMA-positivity prior to PSMA-targeted therapy.

Background: In clinical practice, several radiopharmaceuticals are used for PSMA-PET imaging, each with distinct biodistribution patterns. This may impact treatment decisions and outcomes, as eligibility for PSMA-directed radioligand therapy is usually assessed by comparing tumoral uptake to normal liver uptake as a reference. In this study, we aimed to compare tracer uptake intraindividually in various reference regions including liver, parotid gland and spleen as well as the respective tumor-to-background ratios (TBR) of different F-labeled PSMA ligands to today's standard radiopharmaceutical Ga-PSMA-11 in a series of patients with biochemical recurrence of prostate cancer who underwent a dual PSMA-PET examination as part of an individualized diagnostic approach.

Effect of Acute Hypoxia Exposure on the Availability of A Adenosine Receptors and Perfusion in the Human Brain.

In animal studies it has been observed that the inhibitory neuromodulator adenosine is released into the cerebral interstitial space during hypoxic challenges. Adenosine's actions on the A adenosine receptor (AAR) protect the brain from oxygen deprivation and overexertion through adjustments in cerebral blood flow, metabolism, and electric activity. Using 8-cyclopentyl-3-(3-[F]fluoropropyl)-1-propylxanthine ([F]CPFPX), a PET tracer for the AAR, we tested the hypothesis that hypoxia-induced adenosine release reduces AAR availability in the human brain.