The Predictive Role of Metabolic Volume Segmentation Compared to Semiquantitative PET Parameters in Diagnosis of LVAD Infection using [F]FDG Imaging.

Purpose: Left ventricular assisting device (LVAD) is a vital mechanical circulatory assist device for patients with end-stage heart disease, serving as either a bridge to transplantation or palliative destination therapy. Yet device infection represents a major lethal complication, warranting a multi-step, complex therapy approach including an urgent device exchange or heart transplantation. Still, timely diagnosis of site and extent of VAD-specific infection for a proper therapy planning poses challenges in regular clinical care.

2,5-Dimethoxy-4-iodoamphetamine and altanserin induce region-specific shifts in dopamine and serotonin metabolization pathways in the rat brain.

Purpose: For understanding the neurochemical mechanism of neuropsychiatric conditions associated with cognitive deficits it is of major relevance to elucidate the influence of serotonin (5-HT) agonists and antagonists on memory function as well dopamine (DA) and 5-HT release and metabolism. In the present study, we assessed the effects of the 5-HT receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) and the 5-HT receptor altanserin (ALT) on object and place recognition memory and cerebral neurotransmitters and metabolites in the rat.

Methods: Rats underwent a 5-min exploration trial in an open field with two identical objects.

5-HT and 5-HT receptor effects on recognition memory, motor/exploratory behaviors, emotionality and regional dopamine transporter binding in the rat.

Both dopamine (DA) and serotonin (5-HT) play key roles in numerous functions including motor control, stress response and learning. So far, there is scarce or conflicting evidence about the effects of 5-HT1A and 5-HT2A receptor (R) agonists and antagonists on recognition memory in the rat. This also holds for their effect on cerebral DA as well as 5-HT release.

The 5-HT receptor agonist 8-OH-DPAT modulates motor/exploratory activity, recognition memory and dopamine transporter binding in the dorsal and ventral striatum.

In the present studies, we assessed the effect of the 5-HT receptor (R) agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on motor and exploratory behaviors, object and place recognition and dopamine transporter (DAT) and serotonin transporter (SERT) binding in the rat brain. In Experiment I, motor/exploratory behaviors were assessed in an open field after injection of either 8-OH-DPAT (0.1 and 3 mg/kg) or vehicle for 30 min without previous habituation to the open field.

Intra-Individual Comparison of Physiologic [Ga]Ga-PSMA-11 and [F]PSMA-1007 Uptake in Ganglia in Patients with Prostate Cancer: A Retrospective, Monocentric Analysis.

Background: Several studies indicate, particularly in the case of [18F]PSMA-1007, a relatively high rate of detection of ganglia in PSMA PET imaging. Ganglia are an integral part of the sympathetic portion of the autonomous nervous system. To date, no studies have directly compared [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 ganglionic uptake intra-individually and analyzed the underlying molecular and physical mechanisms of different detection rates.

PSMA-1007 Uptake in Ganglia of the Sympathetic Trunk and Its Intra-individual Reproducibility.

Aim/purpose: F-labeled PSMA ligands offer various advantages as PET tracers over Ga-labeled PSMA counterparts. Especially, an improved spatial resolution leads to improved detection rates of smaller prostate cancer (PCa) lesions. However, physiological PSMA uptake of ganglia of the sympathetic trunk can be quickly misinterpreted as possible PSMA-positive lymph node metastases.

Distinguishing Benign and Malignant Findings on [ Ga]-FAPI PET/CT Based on Quantitative SUV Measurements.

Aim/purpose: Fibroblast activation protein (FAP) is overexpressed by cancer-associated fibroblasts. However, activated fibroblasts have been shown to play a significant role also in certain benign conditions such as wound healing or chronic inflammation. Therefore, the current study aimed to identify whether FAPI uptake might differ between malignant lesions and benign conditions.

Head-to-head Intra-individual Comparison of [Ga]-FAPI and [F]-FDG PET/CT in Patients with Bladder Cancer.

Aim/purpose: Fibroblast activation protein-(FAP)-ligands, a novel class of tracers for PET/CT imaging, demonstrated promising results in previous studies in various malignancies compared to standard [F]FDG PET/CT. Ga-labeled fibroblast activation protein inhibitor-([Ga]Ga-DOTA-FAPI)-PET/CT impresses with sharp contrasts in terms of high tumor uptake and low background noise leading to clear delineation. [F]FDG PET/CT has limited accuracy in bladder cancer due to high background signal.

The 5-HT receptor antagonist WAY-100635 decreases motor/exploratory behaviors and nigrostriatal and mesolimbocortical dopamine D receptor binding in adult rats.

Serotonin(5-HT)ergic projections run from the raphe nuclei to dopamin(DA)ergic cells in substantia nigra/ventral tegmental area (SN/VTA) and to the terminal fields of DA neurons in nucleus accumbens, caudateputamen and neocortex. In the present studies, we assessed the effect of the 5-HT receptor (R) antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarbox-amide maleate (WAY-100635) on motor and exploratory behaviors and on DR binding in the rat brain with in vivo imaging methods. DR binding was determined in the same animals after systemic application of WAY-100635 (0.

Serotonergic Modulation of Nigrostriatal and Mesolimbic Dopamine and Motor/Exploratory Behaviors in the Rat.

The 5-HT receptor (R) is known to modulate dopamine (DA) release in the mammalian brain. Altanserin (ALT) and 2,5-dimethoxy-4-iodoamphetamine (DOI) act as 5-HTR antagonist and agonist, respectively. In the present study, we assessed the effects of ALT and DOI on motor and exploratory behaviors and on DR binding in the rat brain with imaging methods.

GABAergic and glutamatergic effects on nigrostriatal and mesolimbic dopamine release in the rat.

In this review, a series of experiments is presented, in which γ-amino butyric acid (GABA)ergic and glutamatergic effects on dopamine function in the rat nigrostriatal and mesolimbic system was systematically assessed after pharmacological challenge with GABAA receptor (R) and and N-methyl d-aspartate (NMDA)R agonists and antagonists. In these studies, [123I]iodobenzamide binding to the D2/3R was mesured in nucleus accumbens (NAC), caudateputamen (CP), substantia nigra/ventral tegmental area (SN/VTA), frontal (FC), motor (MC) and parietal cortex (PC) as well as anterior (aHIPP) and posterior hippocampus (pHIPP) with small animal SPECT in baseline and after injection of either the GABAAR agonist muscimol (1 mg/kg), the GABAAR antagonist bicuculline (1 mg/kg), the NMDAR agonist d-cycloserine (20 mg/kg) or the NMDAR antagonist amantadine (40 mg/kg). Muscimol reduced D2/3R binding in NAC, CP, SN/VTA, THAL and pHIPP, while, after amantadine, decreases were confined to NAC, CP and THAL.

Differential effects of D-cycloserine and amantadine on motor behavior and D receptor binding in the nigrostriatal and mesolimbic system of the adult rat.

D-cycloserine (DCS) and amantadine (AMA) act as partial NMDA receptor (R) agonist and antagonist, respectively. In the present study, we compared the effects of DCS and AMA on dopamine DR binding in the brain of adult rats in relation to motor behavior. DR binding was determined with small animal SPECT in baseline and after challenge with DCS (20 mg/kg) or AMA (40 mg/kg) with [I]IBZM as radioligand.

Amantadine enhances nigrostriatal and mesolimbic dopamine function in the rat brain in relation to motor and exploratory activity.

Purpose: The present study assessed the influence of the NMDA receptor (R) antagonist amantadine (AMA) on cerebral dopamine DR binding in relation to motor and exploratory activity in the rat.

Methods: DR binding was determined in anaesthetized animals with small animal SPECT in baseline and after challenge with AMA (10 or 40 mg/kg) using [I]IBZM as radioligand. Immediately post-challenge and prior to radioligand administration, motor/exploratory behaviors were assessed for 30 min in an open field.

GABAergic Control of Nigrostriatal and Mesolimbic Dopamine in the Rat Brain.

The present study assessed the effects of the GABA receptor (R) agonist muscimol (MUS), and the GABAR antagonist bicuculline (BIC) on neocortical and subcortical radioligand binding to dopamine DRs in relation to motor and exploratory behaviors in the rat. DR binding was measured with small animal SPECT in baseline and after challenge with either 1 mg/kg MUS or 1 mg/kg BIC, using [I]IBZM as radioligand. Motor/exploratory behaviors were assessed for 30 min in an open field prior to radioligand administration.

GABAergic control of neostriatal dopamine D receptor binding and behaviors in the rat.

Purpose: The present study assessed the influence of the GABA receptor agonist muscimol and the GABA receptor antagonist bicuculline on neostriatal dopamine D receptor binding in relation to motor and exploratory behaviors in the rat.

Methods: D receptor binding was measured in baseline and after challenge with either 1mg/kg muscimol or 1mg/kg bicuculline. In additional rats, D receptor binding was measured after injection of saline.

DAT versus D2 receptor binding in the rat striatum: l-DOPA-induced motor activity is better predicted by reuptake than release of dopamine.

The reuptake and release of dopamine (DA) can be estimated using in vivo imaging methods by assessing the competition between endogenous DA and an administered exogenous DA transporter (DAT) and D2 receptor (D2 R) radioligand, respectively. The aim of this study was to investigate the comparative roles of DA release vs DA reuptake in the rat striatum with small animal SPECT in relation to l-DOPA-induced behaviors. DAT and D2 R binding, together with behavioral measures, were obtained in 99 rats in response to treatment with either 5 or 10 mg/kg l-DOPA or vehicle.

Intranasal Dopamine Reduces In Vivo [(123)I]FP-CIT Binding to Striatal Dopamine Transporter: Correlation with Behavioral Changes and Evidence for Pavlovian Conditioned Dopamine Response.

Purpose: Dopamine (DA), which does not cross the blood-brain barrier, has central and behavioral effects when administered via the nasal route. Neither the mechanisms of central action of intranasal dopamine (IN-DA), nor its mechanisms of diffusion and transport into the brain are well understood. We here examined whether IN-DA application influences dopamine transporter (DAT) binding in the dorsal striatum and assessed the extent of binding in relation to motor and exploratory behaviors.

Corrigendum: Relationship Between L-DOPA-Induced Reduction in Motor and Exploratory Activity and Striatal Dopamine D2 Receptor Binding in the Rat.

[This corrects the article on p. 352 in vol. 9, PMID: 26778989.

FP-CIT- and IBZM-SPECT in Corticobasal Syndrome: Results from a Clinical Follow-Up Study.

Objective: To evaluate the striatal presynaptic dopamine transporter (FP-CIT-SPECT) and postsynaptic D2 receptor (IBZM-SPECT) binding in patients with corticobasal syndrome (CBS).

Background: FP-CIT and IBZM are commercially available and approved SPECT tracers for in vivo molecular imaging of pre- and postsynaptic nigrostriatal neuronal degeneration, but only few data for CBS are available.

Methods: 23 patients meeting clinical criteria for early- to mid-stage CBS (disease duration ≤4 years) were examined with SPECT radiotracers FP-CIT and IBZM.

Identification of different pathways of electron injection in dye-sensitised solar cells of electrodeposited ZnO using an indoline sensitiser.

Charge transfer dynamics in fully operational dye sensitised solar cells consisting of an electrolyte or organic spiroOMeTAD in contact with a highly porous electrodeposited ZnO film sensitised with a monolayer of the indoline dye DN216 were observed using ultrafast transient absorption spectroscopy. From the temporal evolution of spectral signatures assigned with the help of spectroelectrochemical experiments to the population and depopulation of initial, transient and final states, a model was completed for the multistep injection of photoexcited electrons from the molecular absorber to the ZnO acceptor. Injection was found to occur via three different paths with three characteristic rates: directly from the dye's lowest unoccupied molecular orbital into the ZnO conduction band (200 fs) and via intermediate molecular dominated and surface dominated hybrid states (2 ps and 10 ps, respectively).

Relationship Between L-DOPA-Induced Reduction in Motor and Exploratory Activity and Striatal Dopamine D2 Receptor Binding in the Rat.

Purpose: The present study assessed the influence of L-DOPA administration on neostriatal dopamine (DA) D2 receptor binding in relation to motor and exploratory behaviors in the rat.

Methods: D2 receptor binding was measured in baseline, after challenge with the aromatic L-amino acid decarboxylase inhibitor benserazide, and after challenge with either 5 or 10 mg/kg L-DOPA plus benserazide. Additional rats received injections of saline.

Relationship between L-DOPA-induced reduction in motor and exploratory activity and degree of DAT binding in the rat.

Purpose: The present study assessed the influence of L-DOPA administration on neostriatal dopamine (DA) transporter (DAT) binding in relation to motor and exploratory behaviors in the rat.

Methods: Rats received injections of 5 mg/kg L-DOPA, 10 mg/kg L-DOPA or vehicle. Motor and exploratory behaviors were assessed for 30 min in an open field prior to administration of [(123)I]FP-CIT.

Influence of counter-anions during electrochemical deposition of ZnO on the charge transport dynamics in dye-sensitized solar cells.

Porous ZnO/EosinY films have been electrochemically deposited by oxygen reduction in the presence of a zinc salt from EosinY-containing aqueous solutions, with either chloride or perchlorate as the counter anion. EosinY was removed and the films were sensitised by D149. These electrodes were used for dye-sensitised solar cells (DSCs), and charge transport in the porous network was studied by intensity modulated current/voltage spectroscopy (IMVS/IMPS) and electrochemical impedance spectroscopy (EIS) under illumination.

Effects of L-DOPA on striatal iodine-123-FP-CIT binding and behavioral parameters in the rat.

Purpose: The effect of clinical L-3,4-dihydroxyphenylalanine (L-DOPA) doses on the binding of [121I]N-Ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (121[I]FP-CIT) to the rat dopamine transporter (DAT) was investigated using small animal single-photon emission computed tomography.

Materials And Methods: DAT binding was measured at baseline, after challenge with the aromatic L-amino acid decarboxylase inhibitor benserazide, and after challenge with either 5 or 10 mg/kg L-DOPA plus benserazide. For baseline and challenges, striatal equilibrium ratios (V3'') were computed as an estimation of the binding potential.

Pharmacological challenge and synaptic response - assessing dopaminergic function in the rat striatum with small animal single-photon emission computed tomography (SPECT) and positron emission tomography (PET).

Disturbances of dopaminergic neurotransmission may be caused by changes in concentrations of synaptic dopamine (DA) and/or availabilities of pre- and post-synaptic transporter and receptor binding sites. We present a series of experiments which focus on the regulatory mechanisms of the dopamin(DA)ergic synapse in the rat striatum. In these studies, DA transporter (DAT) and/or D(2) receptor binding were assessed with either small animal single-photon emission computed tomography (SPECT) or positron emission tomography (PET) after pharmacological challenge with haloperidol, L-DOPA and methylphenidate, and after nigrostriatal 6-hydroxydopamine lesion.