Thomas L Collier

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The development of sigma (sigma) receptor radioligands has become the focus of research over the past few years due to their potential uses in nuclear medicine. It has been shown that a wide variety of human tumor cell lines express sigma receptors, including malignant melanoma and tumors of the colon, lung, brain, breast and testes. To provide potential(More)
Carbon-11-labeled carbon dioxide is the most common feedstock for the synthesis of positron emission tomography radiotracers and can be directly used for 11 C-carbonylation. Herein, we report the development of an apparatus that takes advantage of "in-loop" technologies to facilitate robust and reproducible syntheses of 11 C-carbonyl-based radiotracers by(More)
Sigma-1 receptors are widely expressed in the mammalian brain and also in organs of the immune, endocrine and reproductive systems. Based on behavioral and pharmacological assessments, sigma-1 receptors are important in memory and cognitive processes, and are thought to be involved in specific psychiatric illnesses, including schizophrenia, depression, and(More)
1-(3-Fluoropropyl)-4-(4-cyanophenoxymethyl)piperidine (1) has been synthesized as a selective high affinity (Ki = 4.3 nM) ligand for sigma-1 receptors (Ki sigma-1/sigma2 = 0.03). The corresponding radioligand, 18F-1, was synthesized via nucleophilic [18F]fluoride displacement from the appropriate N-alkylmesylate precursor. After HPLC purification, 18F-1 was(More)
Sigma receptors have been implicated in a myriad of cellular functions, biological processes and diseases. While the precise biological functions of sigma receptors have not been elucidated, recent work has shed some light on to these enigmatic systems. Sigma receptors have recently been a target of drug development related to psychiatric and neurological(More)
Alzheimer's disease (AD) and related dementias show increasing clinical prevalence, yet our understanding of the etiology and pathobiology of disease-related neurodegeneration remains limited. In this regard, noninvasive imaging with radiotracers for positron emission tomography (PET) presents a unique tool for quantifying spatial and temporal changes in(More)
Microfluidics technology has emerged as a powerful tool for the radiosynthesis of positron emission tomography (PET) and single-photon emission computed tomography radiolabeled compounds. In this work, we have exploited a continuous flow microfluidic system (Advion, Inc., USA) for the [(18) F]-fluorine radiolabeling of the malonic acid derivative, [(18) F](More)
Several halogenated 4-(4-phenoxymethyl)piperidines were synthesized as potential sigma receptor ligands. The affinity and selectivity of these compounds were determined using in vitro receptor binding assays, and their log P values were estimated using HPLC analysis. The effect of various N-substituents on the sigma-1 and sigma-2 dissociation constants was(More)
Molecules labelled with the unnatural isotope fluorine-18 are used for positron emission tomography. Currently, this molecular imaging technology is not exploited at its full potential because many (18)F-labelled probes are inaccessible or notoriously difficult to produce. Typical challenges associated with (18)F radiochemistry are the short half-life of(More)
UNLABELLED Fatty acid oxidation defects are being increasingly identified as causes of abnormal heart function and sudden death in children. Children with medium-chain acyl-coenzyme A (acyl-CoA) dehydrogenase defects can metabolize fatty acids labeled in the carboxylic acid end of the compound. Accordingly, our goal was to label a long-chain fatty acid in(More)