| 1. |
- Hall, Håkan, 1963-, et al.
(författare)
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Pharmacological characterization of 18F-labeled vorozole analogues.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Two 18F-labeled analogues of vorozole ([18F]FVOZ and [18F]FVOO) have been developed as potential tools for the in vivo characterization of aromatase. The purpose of the project was to evaluate the pharmacological properties of these radioligands using a combination of in vitro binding and in vivo distribution studies in the rat and primate. Saturation binding studies with the radioligands in homogenates of rat ovary gave KD and Bmax values of 0.21 ± 0.1 nM and 210 ± 20 fmol/mg, respectively, for [18F]FVOZ, and 7.6 ± 1 nM and 293 ± 12 fmol/mg, respectively, for [18F]FVOO. Organ distribution studies in rats showed the highest accumulation in the adrenal glands, with standardized uptake values (SUVs) of 15 to 20, followed by ovaries and liver with SUVs of approximately 5. The SUVs in the remaining organs were between 0.5 and 1.5. There was probably some defluorination of both radioligands, as the accumulation of radioactivity in bone increased with time. The regional distribution in the brain was studied using ex vivo and in vitro autoradiography. In the brain, specific binding of both [18F]FVOZ and [18F]FVOO were found mainly in the amygdala. PET studies were performed in the Rhesus monkey, and these showed displaceable binding in the amygdala and the preoptic area of the hypothalamus. These studies suggest that [18F]FVOZ might be to be a suitable tracer for the study of aromatase in vitro and in vivo, and could be an alternative to [11C]vorozole in human PET-studies.
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| 2. |
- Linnman, Clas, et al.
(författare)
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Elevated [11C]D--Deprenyl Uptake in Chronic Whiplash Associated Disorder Suggests Persistent Musculoskeletal Inflammation
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:4, s. e19182-
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Tidskriftsartikel (refereegranskat)abstract
- There are few diagnostic tools for chronic musculoskeletal pain as structural imaging methods seldom reveal pathological alterations. This is especially true for Whiplash Associated Disorder, for which physical signs of persistent injuries to the neck have yet to be established. Here, we sought to visualize inflammatory processes in the neck region by means Positron Emission Tomography using the tracer C-11 D-deprenyl, a potential marker for inflammation. Twenty-two patients with enduring pain after a rear impact car accident (Whiplash Associated Disorder grade II) and 14 healthy controls were investigated. Patients displayed significantly elevated tracer uptake in the neck, particularly in regions around the spineous process of the second cervical vertebra. This suggests that whiplash patients have signs of local persistent peripheral tissue inflammation, which may potentially serve as a diagnostic biomarker. The present investigation demonstrates that painful processes in the periphery can be objectively visualized and quantified with PET and that C-11 D-deprenyl is a promising tracer for these purposes.
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| 3. |
- Obaidur, Rahman, 1963-, et al.
(författare)
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Automated synthesis of 18F-labelled analogues of etomidate, vorozole and harmine using commercial synthesizer TRACERLab FXFN
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 18F-Labelled analogues of three biologically interesting compounds, ethyl 1-[(1R)-1-phenylethyl]-1H-imidazole-5-carboxylate (ETO), 6-[(S)-(4-chlorophenyl)-(1H)-1,2,4-triazol-1-yl)methyl]-1-methyl-1H-benzotriazole (VOZ) and 7-methoxy-1-methyl-9H-β-carboline (HAR) were synthesized by one-step nucleophilic fluorination. The 18F-labelled products were obtained with 20–30% isolated decay-corrected radiochemical yields and the radiochemical purities were over 99% in all cases. The labelling syntheses were performed using fully automated commercial synthesizer TRACERLab FXFN. The automation of the syntheses of these three promising PET tracers using a commercial synthesizer will make them accessible for clinical applications.
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| 4. |
- Blom, Elisabeth, et al.
(författare)
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[F-18]/F-19 exchange in fluorine containing compounds for potential use in F-18-labelling strategies
- 2009
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Ingår i: Journal of labelled compounds & radiopharmaceuticals. - : Wiley. - 0362-4803 .- 1099-1344. ; 52:12, s. 504-511
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Tidskriftsartikel (refereegranskat)abstract
- Exchange of [F-18]fluoride with F-19 in various organofluorine compounds in concentrations ranging from 0.06 to 56 mM was explored. We aimed to explore whether exchange reactions can be a potential useful labelling strategy, when there are no requirement of high specific radioactivity. Parameters such as solvents, temperature, conventional vs microwave heating, and the degree of fluorine load in some aromatic and alkyl compounds were investigated with regard to radiochemical yield and specific radioactivity. A series of fluorobenzophenones (1-6), 1-(4-fluorophenyl)ethanone (7), various activated and deactivated fluoro benzenes (8-16), N-(pentafluorophenyl)benzamide (17), (pentafluorophenyl)formamide (18), (tridecafluorohexyl) benzene (19) and tetradecafluorohexane (20) were subjected to [F-18]/F-19 exchange. To test this strategy to label biologically active molecules containing fluorine atoms in an aryl group, two analogues of WAY-100635 (21-22), Lapatinib (23), 2,5,6,7,8-pentafluoro-3-methyinaphthoquinone (24) and 1-(2,4-difluorophenyl)-3-(4-fluorophenyl)propan-l-one (25) were investigated. The multi-fluorinated molecules containing an electron-withdrawing group were successfully labelled at room temperature, whereas the monofluorinated, as well as those containing an electron-donating group, required heating for the exchange reaction to take place.
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| 5. |
- Blom, Elisabeth, 1979-, et al.
(författare)
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Synthesis and in vitro evaluation of 18F-β-carboline alkaloids as PET ligands
- 2008
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Ingår i: Journal of labelled compounds & radiopharmaceuticals. - : Wiley. - 0362-4803 .- 1099-1344. ; 51:6, s. 277-282
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Tidskriftsartikel (refereegranskat)abstract
- A one-step 18F-labelling strategy was used to prepare four 18F-labelled analogues of 7-methoxy-1-methyl-9H-β-carboline (harmine): 7-(2-[18F]fluoroethoxy)-1-methyl-9H-β-carboline (5), 7-(3-[18F]fluoro-propoxy)-1-methyl-9H-β-carboline (6), 7-[2-(2-[18F]fluoroethoxy)ethoxy]-1-methyl-9H-β-carboline (7), and 7-{2-[2-(2-[18F]fluoroethoxy)ethoxy]-ethoxy}-1-methyl-9H-β-carboline (8). These were synthesized as potential PET ligands for monoamine oxidase A. A solution of pure labelled compound in buffer was obtained in < 70 min from end of radionuclide production, with a decay-corrected yield of up to 23%. The average specific binding to MAO-A in rat brain, determined by autoradiography experiments, was highest for compounds 7 and 8 (89 ± 2 and 96 ± 1% respectively), which was obtained at < 1 nM radioligand concentration.
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| 6. |
- Eriksson, Olof, et al.
(författare)
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Preclinical evaluation of a 68Ga-labeled biotin analogue for applications in islet transplantation
- 2012
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Ingår i: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 39:3, s. 415-421
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION:Islet transplantation is a promising treatment for type 1 diabetes mellitus, but the fate of the cells after intraportal infusion is unclear. It is therefore imperative to develop novel techniques for noninvasive imaging and quantification of events following islet transplantation.METHODS:Small islet-like microbeads, avidin-covered agarose resins (AARs), were used as a model system for islet transplantation. Capability for specific [(68)Ga]Ga-DOTA-(PEG)(2)-biotin uptake and retention for either AARs or human islets conjugated with avidin by means of a heparin scaffold was studied in vitro. Biodistribution of the novel positron emission tomography (PET) tracer [(68)Ga]Ga-DOTA-(PEG)(2)-biotin was evaluated in mice treated by intraportal transplantation of AARs by μPET/computed tomography and ex vivo organ distribution and compared with control mice.RESULTS:AARs had high capability to bind [(68)Ga]Ga-DOTA-(PEG)(2)-biotin, close to 50% of administrated tracer/μl in vitro (>0.25 MBq/μl). Avidin-tagged human islets could bind on average 2.2% of administered tracer/μl. Specificity (>90%) and retention (>90% after 1 h) were high for both AARs and avidin-tagged islets. Hepatic tracer uptake and retention were increased in mice transplanted with AARs [standardized uptake value (SUV)=2.6] compared to the untreated group (SUV=1.4). In vivo uptake of tracer to AARs was blocked by preadministration of unlabeled biotin.CONCLUSIONS:Avidin-tagged islet-like objects can be tracked in hepatic volume after intraportal transplantation by using [(68)Ga]Ga-DOTA-(PEG)(2)-biotin and PET.
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| 7. |
- Itsenko, Oleksiy, et al.
(författare)
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The Use of Lithium Amides in the Palladium-Mediated Synthesis of [Carbonyl-11C]Amides
- 2007
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Ingår i: European Journal of Organic Chemistry. - Weinheim, Germany : Wiley. - 1434-193X .- 1099-0690. ; 2007:26, s. 4337-4342
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Tidskriftsartikel (refereegranskat)abstract
- Weakly nucleophilic amines were converted into the corresponding lithium amides and used in either one- or two-pot palladium mediated-reactions with [11C]carbon monoxide and aryl iodides. It was found that palladium acyl complexes may be prepared in a separate step and have sufficient lifetime to be used in a subsequent reaction with a nucleophile. This two-pot procedure was used for the labelling synthesis of eleven amides (nine of which are analogues of WAY-100635, a 5-HT1A radioligand) from weakly nucleophilic amines. The results were compared to a direct one-pot procedure using lithium amides. Both approaches extend the scope of palladium-mediated carbonylation using [11C]carbon monoxide and aryl iodides allowing use of weakly nucleophilic amines.
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| 8. |
- Nordberg, Agneta, et al.
(författare)
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The use of PET in Alzheimer disease
- 2010
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Ingår i: Nature Reviews Neurology. - : Springer Science and Business Media LLC. - 1759-4758 .- 1759-4766. ; 6:2, s. 78-87
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Forskningsöversikt (refereegranskat)abstract
- In Alzheimer disease (AD), which is the most common cause of dementia, the underlying disease pathology most probably precedes the onset of cognitive symptoms by many years. Thus, efforts are underway to find early diagnostic markers as well as disease-modifying treatments for this disorder. PET enables various brain systems to be monitored in living individuals. In patients with AD, PET can be used to investigate changes in cerebral glucose metabolism, various neurotransmitter systems, neuroinflammation, and the protein aggregates that are characteristic of the disease, notably the amyloid deposits. These investigations are helping to further our understanding of the complex pathophysiological mechanisms that underlie AD, as well as aiding the early and differential diagnosis of the disease in the clinic. In the future, PET studies will also be useful for identifying new therapeutic targets and monitoring treatment outcomes. Amyloid imaging could be useful as early diagnostic marker of AD and for selecting patients for anti-amyloid-beta therapy, while cerebral glucose metabolism could be a suitable PET marker for monitoring disease progression. For the near future, multitracer PET studies are unlikely to be used routinely in the clinic for AD, being both burdensome and expensive; however, such studies are very informative in a research context.
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| 9. |
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