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De P, Roy K. QSAR modeling of PET imaging agents for the diagnosis of Parkinson’s disease targeting dopamine receptor. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02687-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Eleventh international symposium on radiopharmaceutical chemistry: Abstracts. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2580370301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Adak S, Bhalla R, Vijaya Raj KK, Mandal S, Pickett R, Luthra SK. Radiotracers for SPECT imaging: current scenario and future prospects. ACTA ACUST UNITED AC 2012. [DOI: 10.1524/ract.2011.1891] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abstract
Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper.
The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology.
Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [123I]FP-CIT (DaTSCANTM) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [123I]mIBG (AdreViewTM) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis.
While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also makes them more attractive in developing countries where the cost of a scan is still prohibitive for many patients.
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Affiliation(s)
| | - R. Bhalla
- GE Healthcare Medical Diagnostics, The Grove Centre, Amersham HP7 9LL, Großbritannien
| | - K. K. Vijaya Raj
- GE Healthcare Medical Diagnostics, John F Welch Technology Center, Bangalore, Indien
| | - S. Mandal
- GE Healthcare Medical Diagnostics, John F Welch Technology Center, Bangalore, Indien
| | - R. Pickett
- GE Healthcare Medical Diagnostics, The Grove Centre, Amersham HP7 9LL, Großbritannien
| | - S. K. Luthra
- GE Healthcare Medical Diagnostics, The Grove Centre, Amersham HP7 9LL, Großbritannien
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Stark D, Piel M, Hübner H, Gmeiner P, Gründer G, Rösch F. In vitro affinities of various halogenated benzamide derivatives as potential radioligands for non-invasive quantification of D2-like dopamine receptors. Bioorg Med Chem 2007; 15:6819-29. [PMID: 17765546 DOI: 10.1016/j.bmc.2007.07.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 07/12/2007] [Accepted: 07/17/2007] [Indexed: 11/25/2022]
Abstract
Benzamide derivatives as radiotracers have played an important role in diagnosing malfunction in dopaminergic neurotransmission. A variety of halogenated and two unsubstituted benzamide derivatives were synthesised and their in vitro affinities to dopaminergic, serotonergic and adrenergic receptors and their lipophilicities were determined. As references IBZM (3), raclopride (4) and FLB457 (5) were tested as well. The two iodinated compounds NAE (27) and NADE (28) displayed K(i) values of 0.68 and 14 nM for the D(2) receptor. The well-established radiotracers FP (1) and DMFP (2) showed affinities in the same range as did the brominated compounds NABrE (29) and NABrDE (30). The log D(7.4) values of 2.91 for NAE (27) and of 2.81 for NADE (28) are in the range of those found for IBZM (3), FP (1) and DMFP (2). These facts allow to expect good properties for the two iodinated compounds NAE (27) and NADE (28) regarding in vivo imaging with SPECT.
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Affiliation(s)
- Daniela Stark
- Institute of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128, Mainz, Germany
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Vitale AA, Calviño MA, Ferrari CC, Stahl AE, Pomilio AB. Preparation and biological evaluation of technetium-99m-phenylethylamine complexes. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580360602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Zamrini E, De Santi S, Tolar M. Imaging is superior to cognitive testing for early diagnosis of Alzheimer’s disease. Neurobiol Aging 2004; 25:685-91. [PMID: 15172748 DOI: 10.1016/j.neurobiolaging.2004.02.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Revised: 02/16/2004] [Accepted: 02/18/2004] [Indexed: 11/18/2022]
Abstract
Alzheimer's disease (AD) starts at a molecular level possibly decades earlier than could be detected by neuropsychological tests (NPTs). Neuropathological and neuroimaging data suggest that amyloid accumulation precedes the clinical onset of AD. Disease-modifying agents would have to be used early to alter the course of AD. Therefore, preclinical diagnosis is necessary. Structural and functional neuroimaging are superior for detection of the earliest stages of AD. Magnetic resonance imaging (MRI) and positron emission tomography (PET) techniques, including amyloid visualization, will have therapeutic importance for prevention as well as intervention as further refinements of current imaging techniques and biochemical markers occur. Neuropsychological tests measure the effect of pathology for an individual based upon norms obtained from an artificial population-often white and relatively highly educated. Unless serial NPTs are performed, the individual is compared to a population to which they may not conform. Neuroimaging can provide objective measures of preclinical disease state and, when measured serially, rate of change. Such information can be used in prevention trials.
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Affiliation(s)
- Edward Zamrini
- Department of Neurology, 454 Sparks Center, 1720 7th Avenue South, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Xu G, Hartman TL, Wargo H, Turpin JA, Buckheit RW, Cushman M. Synthesis of alkenyldiarylmethane (ADAM) non-nucleoside HIV-1 reverse transcriptase inhibitors with non-identical aromatic rings. Bioorg Med Chem 2002; 10:283-90. [PMID: 11741777 DOI: 10.1016/s0968-0896(01)00282-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The existing methods for the synthesis of alkenyldiarylmethane (ADAM) non-nucleoside reverse transcriptase inhibitors proceed from symmetrical benzophenones and therefore result in products with identical aromatic rings. New methods have therefore been devised for the preparation of stereochemically defined ADAMs with non-identical aromatic rings. The new routes rely on palladium-catalyzed reactions, including Sonogashira, Suzuki, Stille, and hydroarylation methodology. Several of the new ADAMs inhibited the cytopathic effect of HIV-1 in cell culture and HIV-1 reverse transcriptase at submicromolar concentrations.
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Affiliation(s)
- Guozhang Xu
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, IN 47907, USA
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Mukherjee J, Yang ZY, Das MK, Brown T. Fluorinated benzamide neuroleptics--III. Development of (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-[18F]fluoropropyl)-2, 3-dimethoxybenzamide as an improved dopamine D-2 receptor tracer. Nucl Med Biol 1995; 22:283-96. [PMID: 7627142 DOI: 10.1016/0969-8051(94)00117-3] [Citation(s) in RCA: 181] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have prepared five new analogs (n-propyl, iso-propyl, allyl, n-butyl, and iso-butyl) of the dopamine D-2 receptor antagonist, FPMB which result from modifications of the ethyl group at the pyrrolidine nitrogen in FPMB. As expected, all new derivatives showed higher apparent lipophilicity (log kw), with iso-butyl being the most lipophilic (log kw = 2.52), followed by the allyl derivative (log kw = 2.43). The allyl group showed the largest increase in affinity (from 0.26 nM for the ethyl substituent to 0.03 nM for the allyl substituent, almost 10-fold), followed by the n-propyl substituent which showed approximately five-fold better affinity than did the ethyl substituent. Radiosynthesis of (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-[18F]fluoropropyl)-2, 3-dimethoxybenzamide ([18F]fallypride) was carried out by nucleophilic substitution reaction of (S)-N-[(1-allyl-2-pyrrolidinyl) methyl]-5-(3-tosyloxypropyl)-2,3-dimethoxybenzamide with no carrier added 18F-. [18F]Fallypride was obtained in approximately 20-40% yields (EOS/EOB, decay corrected) in specific activities of 900-1700 Ci/mmol after reverse phase HPLC purification in 60 min from EOB. High striatal uptake (upto 2.5% injected dose/g) of [18F]fallypride in rats was observed with striatal/cerebellar ratios of 17, 42, 63 and 122 at 30, 60, 90 and 120 min post-injection, respectively. PET experiments with [18F]fallypride in a cebus monkey showed a brain uptake of 0.10% injected dose/cc. In rhesus monkeys [18F]fallypride showed rapid specific uptake in the striata (0.04-0.06% injected dose/cc) with striata/cerebellum ratios of approx. 3.0 at 14 min, 5.0 at 35 min and 8 at 70 min post-injection. Specifically bound [18F]fallypride was displaced with haloperidol (1 mg/kg) with a half-life of 18 min in the rhesus monkey.
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Affiliation(s)
- J Mukherjee
- Franklin McLean Institute, Department of Radiology, University of Chicago, IL 60637, USA
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Mach RH, Ehrenkaufer RL, Greenberg JH, Shao L, Morton TE, Evora PH, Nowak PA, Luedtke RR, Cohen D, Reivich M. PET imaging studies of dopamine D2 receptors: comparison of [18F]N-methylspiperone and the benzamide analogues [18F]MABN and [18F]MBP in baboon brain. Synapse 1995; 19:177-87. [PMID: 7784958 DOI: 10.1002/syn.890190305] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A series of positron emission tomography (PET) imaging studies was conducted in a baboon with the benzamide derivatives [18F]2,3-dimethoxy-N-[9-(4-fluorobenzyl)-9-azabicyclo[3.3.1]non an-3 beta-yl]benzamide ([18F]MABN) and [18F]2,3-dimethoxy-N-[1-(4-fluorobenzyl)piperidin-4-yl]be nza mide ([18F]MBP). Studies were also conducted with the butyrophenone [18F]N-methylspiperone (NMSP) for comparison. Tissue-time activity curves of [18F]MABN are similar to those of [18F]NMSP since both compounds displayed approximately the same uptake in the basal ganglia and displayed irreversible binding kinetics in vivo. However, the rapid rate of clearance from the cerebellum and high basal ganglia:cerebellum ratio of [18F]MABN indicate that this compound has a much lower amount of nonspecific binding than [18F]NMSP. [18F]MBP displayed a higher uptake in the basal ganglia relative to [18F]NMSP and [18F]MABN and exhibited reversible binding kinetics in vivo. This property of [18F]MBP is desirable since the uptake of radioactivity in D2-rich ligands is less likely to be influenced by changes in cerebral blood flow. The current data suggest that both [18F]MABN and [18F]MBP are promising ligands for studying dopamine D2 receptors with PET.
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Affiliation(s)
- R H Mach
- Cerebrovascular Research Center, University of Pennsylvania, Philadelphia 19104, USA
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Eleventh international symposium on radiopharmaceutical chemistry: Abstracts. J Labelled Comp Radiopharm 1995. [DOI: 10.1002/jlcr.2580370101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Laruelle M, Baldwin RM, Rattner Z, al-Tikriti MS, Zea-Ponce Y, Zoghbi SS, Charney DS, Price JC, Frost JJ, Hoffer PB. SPECT quantification of [123I]iomazenil binding to benzodiazepine receptors in nonhuman primates: I. Kinetic modeling of single bolus experiments. J Cereb Blood Flow Metab 1994; 14:439-52. [PMID: 8163586 DOI: 10.1038/jcbfm.1994.55] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The aim of this work was to study the feasibility and reproducibility of in vivo measurement of benzodiazepine receptors with single photon emission computerized tomography (SPECT) in the baboon brain. Arterial and brain regional activities were measured for 420 min in three baboons after single bolus injection of the benzodiazepine antagonist [123I]iomazenil. Data were fit to a three-compartment model to derive the regional binding potential (BP), which corresponds to the product of the receptor density, (Bmax) and affinity (1/KD). Regional BP values (from 114 in striatum to 241 in occipital) were in good agreement with values predicted from in vitro studies. Constraining the regional volume of distribution of the nondisplaceable compartment to the value measured during tracer constant infusion experiments in baboons (Laruelle et al., 1993) improved the identifiability of the rate constants. Each experiment was repeated to investigate the reproducibility of the measurement. The regional average reproducibility was 10 +/- 5%, expressed as coefficient of variation (CV). Results of equilibrium analysis at peak uptake were in good agreement with results of kinetic analysis. Empirical counts ratio methods were found to be poorly sensitive to benzodiazepine receptor density. These studies suggest the feasibility of quantitative measurement of benzodiazepine receptors by kinetic analysis of SPECT data and the inadequacy of empirical methods of analysis, such as counts ratios, to evaluate differences in receptor density.
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Affiliation(s)
- M Laruelle
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06516
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Schmidt DE, Votaw JR, Kessler RM, de Paulis T. Aromatic and amine substituent effects on the apparent lipophilicities of N-[(2-pyrrolidinyl)methyl]-substituted benzamides. J Pharm Sci 1994; 83:305-15. [PMID: 8207673 DOI: 10.1002/jps.2600830309] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipophilic properties of 92 dopamine D-2 receptor antagonists belonging to the substituted benzamide class of compounds (orthopramides and methoxysalicylamides) were determined by octadecylsilane reversed-phase HPLC. The apparent lipophilicity at pH 7.5 (log kw) was obtained from the chromatographic capacity factors in 0.02 M3-(morpholino)propanesulfonic acid (MOPS) buffer at various concentrations of methanol. The experimental log kw values were validated by comparison with the apparent octanol-water partitioning (log Papp) of 15 compounds of low to medium lipophilicity. The global lipophilicity of the neutral molecule (log kwo) was obtained by correcting for ionization of the amine and the phenol, using known relationships for the effects on the pKa (where Ka is the dissociation constant) of aromatic and aliphatic substituents. Multiple regression analysis showed that log kwo can be expressed as the sum of pi contributions and a cross correlation term (sigma rho sigma) for interactions between the aromatic substituents. Comparison between the methoxysalicylamide (raclopride) series and the orthopramide (sulpiride) series demonstrated that an aromatic 6-hydroxy group increased log kw by 0.4 in the 5-halogen series and by 0.8 in the 5-alkyl series, and that a 6-methoxy group decreased log kw by 0.5. These paradoxical effects can be explained by the masking of the polarity of the amide caused by the 6-hydroxy group forming an intramolecular hydrogen bond with the amide carbonyl group. Introduction of an additional ortho-methoxy substituent had the opposite effect because the resulting steric hindrance prevents the amide moiety from adopting a coplanar conformation with the benzene ring. The presence of a substituent in the aromatic 3-position lowered log kw by 0.3 via a combination of steric and electronic influences on the adjacent 2-methoxy group, causing a weakening of the hydrogen bond between the amide and the oxygen atom of the 2-methoxy group. As a result, halogen and alkyl substituents in the 3-position increase the apparent lipophilicity only half that of similar substituents in the 5-position. Substitution with omega-fluoroalkoxyl groups in the aromatic 2- and 3-positions and with omega-fluoroalkyl groups in the 5-position reduced lipophilicities by 0.5 as compared with the corresponding desfluoro derivatives, thereby making them equivalent to an alkyl derivative with one less carbon atom in the chain. In contrast, substitution on the pyrrolidine nitrogen atom with a 2-fluoroethyl or a 3-fluoropropyl group produced compounds with apparent lipophilicities approximately 1.5 and approximately 0.5 higher, respectively, than those of the corresponding N-ethyl derivatives.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- D E Schmidt
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37235
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