Prashanth K. Padakanti

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Accumulation of misfolded α-synuclein in Lewy bodies and Lewy neurites is the pathological hallmark of Parkinson's disease (PD). To identify ligands having high binding potency toward aggregated α-synuclein, we synthesized a series of phenothiazine derivatives and assessed their binding affinity to recombinant α-synuclein fibrils using a fluorescent(More)
The biological properties of the novel monoclonal antibody (mAb) H6-11 and its potential utility for oncological imaging studies were evaluated using in vitro and in vivo assays. Immunoreactivity of H6-11 to the human prostate cancer PC-3 cell line and solid tumor xenografts was initially demonstrated using immunofluorescence staining; the specificity of(More)
2-((4-(1-[(11)C]Methyl-4-(pyridin-4-yl)-1H-pyrazol-3-yl)phenoxy)methyl)-quinoline (MP-10), a specific PDE10A inhibitor (IC(50)=0.18 nM with 100-fold selectivity over other PDEs), was radiosynthesized by alkylation of the desmethyl precursor with [(11)C]CH(3)I, ∼45% yield, >92% radiochemical purity, >370 GBq/μmol specific activity at end of bombardment(More)
Nine fluorine-containing vesicular acetylcholine transporter (VAChT) inhibitors were synthesized and screened as potential PET tracers for imaging the VAChT. Compound 18a was one of the most promising carbonyl-containing benzovesamicol analogs; the minus enantiomer, (-)-18a displayed high potency (VAChT Ki=0.59 ± 0.06 nM) and high selectivity for VAChT(More)
The radiosyntheses and in vivo evaluation of four carbon-11 labeled quinoline group-containing radioligands are reported here. Radiolabeling of [(11)C]1-4 was achieved by alkylation of their corresponding desmethyl precursors with [(11)C]CH3I. Preliminary biodistribution evaluation in Sprague-Dawley rats demonstrated that [(11)C]1 and [(11)C]2 had high(More)
To identify suitable lipophilic compounds having high potency and selectivity for vesicular acetylcholine transporter (VAChT), a heteroaromatic ring or a phenyl group was introduced into the carbonyl-containing scaffold for VAChT ligands. Twenty new compounds with ALogD values between 0.53 and 3.2 were synthesized, and their in vitro binding affinities were(More)
PURPOSE The vesicular acetylcholine transporter (VAChT) is a specific biomarker for imaging presynaptic cholinergic neurons. Herein, two potent and selective (11)C-labeled VAChT inhibitors were evaluated in rodents and nonhuman primates for imaging VAChT in vivo. PROCEDURES For both (-)-[(11)C]2 and (-)-[(11)C]6, biodistribution, autoradiography, and(More)
PURPOSE The vesicular acetylcholine transporter (VAChT) is a specific biomarker for imaging presynaptic cholinergic neurons. The syntheses and C-11 labeling of two potent enantiopure VAChT inhibitors are reported here. PROCEDURES Two VAChT inhibitors, (±)-2 and (±)-6, were successfully synthesized. A chiral HPLC column was used to resolve the enantiomers(More)
Two α-synuclein ligands, 3-methoxy-7-nitro-10H-phenothiazine (2a, Ki = 32.1 ± 1.3 nM) and 3-(2-fluoroethoxy)-7-nitro-10H-phenothiazine (2b, Ki = 49.0 ± 4.9 nM), were radiolabeled as potential PET imaging agents by respectively introducing (11)C and (18)F. The syntheses of [(11)C]2a and [(18)F]2b were accomplished in a good yield with high specific activity.(More)
Two α-synuclein ligands, 3-methoxy-7-nitro-10H-phenothiazine (2a, K i = 32.1 ± 1.3 nM) and 3-(2-fluoroethoxy)-7-nitro-10H-phenothiazine (2b, K i = 49.0 ± 4.9 nM), were radiolabeled as potential PET imaging agents by respectively introducing 11 C and 18 F. The syntheses of [ 11 C]2a and [ 18 F]2b were accomplished in a good yield with high specific activity.(More)