51
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Langen KJ, Roosen N, Coenen HH, Kuikka JT, Kuwert T, Herzog H, Stöcklin G, Feinendegen LE. Brain and brain tumor uptake of L-3-[123I]iodo-alpha-methyl tyrosine: competition with natural L-amino acids. J Nucl Med 1991; 32:1225-9. [PMID: 2045937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
SPECT studies with L-3-[123I]iodo-alpha-methyl tyrosine (IMT) were carried out in 10 patients with different types of brain tumors--first under fasting conditions (basal) and a week later during intravenous infusion of a mixture of naturally-occurring L-amino acids (AA load). An uptake index (UI) was calculated by dividing tissue count rates by the integral of plasma count rates. The UI decreased by 45.6% +/- 15.4% (n = 10, p less than 0.001) for normal brain and by 53.2% +/- 14.1% for gliomas (n = 5, p less than 0.01) during AA load compared to basal conditions, while two meningiomas and a metastasis showed only a minor decrease (23.9 +/- 5.7%, n.s.). Two pituitary adenomas could not be delineated on the SPECT scans. These data indicate that IMT competes with naturally-occurring L-amino acids for transport into normal brain and gliomas. Transport characteristics of IMT into tumors of nonglial origin appear to be different from those of gliomas. For both types of tumors, it is advisable to perform IMT-SPECT under fasting conditions.
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52
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Wienhard K, Pawlik G, Nebeling B, Rudolf J, Fink G, Hamacher K, Stöcklin G, Heiss WD. Estimation of local cerebral glucose utilization by positron emission tomography: comparison of [18F]2-fluoro-2-deoxy-D-glucose and [18F]2-fluoro-2-deoxy-D-mannose in patients with focal brain lesions. J Cereb Blood Flow Metab 1991; 11:485-91. [PMID: 2016357 DOI: 10.1038/jcbfm.1991.92] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A comparative PET study of [18F]2-fluoro-2-deoxy-D-glucose (FDG) and [18F]2-fluoro-2-deoxy-D-mannose (FDM) uptake was performed in 13 patients with focal brain lesions. Differences between FDG and FDM with respect to model rate constants, lumped constant, and estimated metabolic rate for glucose were determined on a regional basis. Across whole brain, the transport rate constant K1* was almost unchanged, whereas k2*, describing the transport back from tissue to plasma, was 6% higher, and the phosphorylation rate constant k3* was 9% lower for FDM compared to FDG. This implies a 20% lower lumped constant for FDM. No significant regional variability of this differential tracer behavior was observed in normal or in lesioned brain tissue. Thus, results from previous FDG studies, where the radiotracer was not 100% pure FDG but contained varying amounts of FDM, can easily be corrected by adjustment of the lumped constant employed in metabolic quantitation.
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53
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Kovács Z, Tárkányi F, Qaim SM, Stöcklin G. Production of 6.5 h 82mRb via the 82Kr(p, n)-process at a low-energy cyclotron--a potential substitute for 82Rb. INTERNATIONAL JOURNAL OF RADIATION APPLICATIONS AND INSTRUMENTATION. PART A, APPLIED RADIATION AND ISOTOPES 1991; 42:831-4. [PMID: 1657832 DOI: 10.1016/0883-2889(91)90220-u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The production of 6.5 h 82mRb, a potential substitute for generator-produced 1.2 min 82Rb in myocardial blood flow studies, is discussed. Using a 82Kr gas target and a low-energy cyclotron it is possible to obtain greater than 100 mCi (greater than 3.7 GBq) of high purity 82mRb. Results of radiation dose calculations for 81Rb/81mKr, 82Rb and 82mRb are reported.
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54
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Kovács Z, Tárkányi F, Qaim S, Stöcklin G. Excitation functions for the formation of some radioisotopes of rubidium in proton induced nuclear reactions on natKr, 82Kr and 83Kr with special reference to the production of 81Rb(81mKr) generator radionuclide. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0883-2889(91)90134-m] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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55
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Wienhard K, Coenen HH, Pawlik G, Rudolf J, Laufer P, Jovkar S, Stöcklin G, Heiss WD. PET studies of dopamine receptor distribution using [18F]fluoroethylspiperone: findings in disorders related to the dopaminergic system. J Neural Transm (Vienna) 1990; 81:195-213. [PMID: 2144427 DOI: 10.1007/bf01245042] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PET studies of dopamine D2-receptor binding were performed in thirty patients with various disorders related to the dopaminergic system and in six healthy controls. Uptake of [18F]fluoroethylspiperone in caudate over three hours was analyzed in terms of several indices of receptor binding:caudate-to-cerebellum activity ratio, concentration of ligand as percentage of injected dose, caudate-to-blood radioactivity ratio, slope of tracer uptake curves, binding potential, kinetic constants of a three compartment model. In 14 patients brain glucose metabolism was also measured. Data on medicated patients demonstrate that the average values of most of the above parameters indicate the decreased number of available D2-receptors whereby, besides an age dependent decline, the caudate-to-cerebellum ratio affords the relatively best distinction among diagnostic groups. In individual cases, large variability among subjects permits only the classification of severe pathologies. Morphological damage and neuronal loss in the striatum may also cause abnormal low values both for the indices of receptor binding and for glucose consumption, thus providing a possible pathogenetic link between receptor dysfunction and impaired energy metabolism.
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56
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Stöcklin G. New 18F-radiopharmaceuticals. Nuklearmedizin 1990; 29:80. [PMID: 2339087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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57
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Langen KJ, Coenen HH, Roosen N, Kling P, Muzik O, Herzog H, Kuwert T, Stöcklin G, Feinendegen LE. SPECT studies of brain tumors with L-3-[123I] iodo-alpha-methyl tyrosine: comparison with PET, 124IMT and first clinical results. J Nucl Med 1990; 31:281-6. [PMID: 2155314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
L-3-[123I]iodo-alpha-methyltyrosine (123IMT) like tyrosine has been reported previously to have a high affinity for a transport system in the blood-brain-barrier (BBB). We examined the kinetic behavior of 124IMT in brain and plasma in two patients with glioblastoma using dynamic positron emission tomography (PET). 124IMT accumulated in brain and tumor tissue, reaching a maximum after 15 min, with a washout of 20% to 35% at 60 min postinjection. Animal experiments confirmed the accumulation of the intact tracer in murine brain, but there was no incorporation into proteins. SPECT studies with 123IMT in patients with different types of brain tumors showed increased uptake in 26 of 32 tumors. Although nonspecific uptake in tumors must be considered, the accumulation of IMT in normal brain and in some tumors with intact BBB suggests a specific uptake of IMT. As transport is the main determinant of initial amino acid uptake, 123IMT appears to be a suitable SPECT tracer of amino acid uptake although it is not incorporated into protein.
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58
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Coenen HH, Kling P, Stöcklin G. Cerebral metabolism of L-[2-18F]fluorotyrosine, a new PET tracer of protein synthesis. J Nucl Med 1989; 30:1367-72. [PMID: 2787848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
L-[2-18F]fluorotyrosine (2-18FTyr) was evaluated as a tracer of cerebral protein synthesis for positron emission tomography (PET). Its metabolism in murine cerebrum was studied. The uptake in brain reaches a value of approximately 2% of the injected dose per gram tissue after 60 min. The incorporation of the tracer into tissue proteins was proven by discontinuous SDS gel electrophoresis. The protein bound fraction of tissue activity increased to 84% and 89% after 60 and 120 min p.i., respectively. High performance liquid chromatography analysis showed a concomitant decrease of free 2-18FTyr in tissue with time. The sum of free 2-18FTyr, tRNA-and protein-bound 2-18FTyr in cerebral tissue gave an almost quantitative activity balance of 96 +/- 4% at all times examined. A significant formation of fluorodopa or fluorodopamine must therefore be excluded. This shows that L-[2-18F]fluorotyrosine is a promising tracer for quantitation of protein synthesis rates with PET based on a three-compartment model.
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59
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Mushtaq A, Qaim S, Stöcklin G. Comparative evaluation of 73Se-production via several routes. J Labelled Comp Radiopharm 1989. [DOI: 10.1002/jlcr.2580260164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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60
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Hamacher K, Hanus J, Stöcklin G. Synthesis of carbon-11 labelled D,L-homocysteine thiolactone. J Labelled Comp Radiopharm 1989. [DOI: 10.1002/jlcr.25802601109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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61
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Biersack HJ, Coenen HH, Stöcklin G, Reichmann K, Bockisch A, Oehr P, Kashab M, Rollmann O. Imaging of brain tumors with L-3-[123I]iodo-alpha-methyl tyrosine and SPECT. J Nucl Med 1989; 30:110-2. [PMID: 2783455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Carbon-11-labeled amino acids have been successfully used to image brain tumors by PET. This study was undertaken to evaluate the potential of L-3-[123I]-iodo-alpha-methyl tyrosine (123IMT) for metabolic imaging of brain tumors. Ten patients (glioblastoma, oligodendroglioma, lymphoma, and metastases) had early and delayed brain SPECT with a rotating gamma camera after i.v.-injection of 200-300 MBq 123IMT. In nine patients the tumors showed intense uptake of the radiotracer. Tumor-to-brain tissue ratios were between 1.4 and 2.6. 123IMT shows potentials for monitoring the effects of brain tumor therapy.
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62
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Scholten B, Qaim S, Stöcklin G. Excitation functions of proton induced nuclear reactions on natural tellurium and enriched 123Te: Production of 123I via the 123Te(p, n)123I-process at a low-energy cyclotron. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0883-2889(89)90187-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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63
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Scholten B, Qaim S, Stöcklin G. Production of 123I at a low-energy cyclotron. J Labelled Comp Radiopharm 1989. [DOI: 10.1002/jlcr.2580260177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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64
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Bodsch W, Coenen HH, Stöcklin G, Takahashi K, Hossmann KA. Biochemical and autoradiographic study of cerebral protein synthesis with [18F]-and [14C]fluorophenylalanine. J Neurochem 1988; 50:979-83. [PMID: 3339368 DOI: 10.1111/j.1471-4159.1988.tb03007.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fluorine-18-labeled ortho or para isomers of L-fluorophenylalanine were used in double-label experiments together with L-[3H]phenylalanine for amino acid incorporation into cerebral proteins of Mongolian gerbil brain. It was demonstrated by qualitative regional comparison of the 18F and 3H autoradiographic images that L-p-[18F]fluorophenylalanine is incorporated into proteins and exhibits a regional cerebral protein synthesis pattern. To a minor extent, L-p-fluorophenyl[3-14C]alanine and L-o-[18F]fluorophenylalanine are hydroxylated in vivo to form labeled tyrosine or tyrosine analogues that are incorporated into cerebral proteins as well. The advantage and validity of the application of L-p-[18F]fluorophenylalanine with positron emission tomography for noninvasive studies of cerebral protein synthesis in humans are evaluated on the basis of an experimental animal approach.
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65
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Mushtaq A, Qaim S, Stöcklin G. Production of 73Se via (p, 3n) and (d, 4n) reactions on arsenic. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0883-2889(88)90146-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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66
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Tárkányi F, Qaim S, Stöcklin G. Excitation functions of 3He- and α-particle induced nuclear reactions on natural krypton: Production of 82Sr at a compact cyclotron. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0883-2889(88)90159-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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67
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Metwally SA, Coenen HH, Stöcklin G. Protection of Functional Groups and Stannylation of Phenylalanine. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1987. [DOI: 10.1246/bcsj.60.4437] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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68
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Drewes LR, Mies G, Hossmann KA, Stöcklin G. Blood-brain transport and regional distribution of bromo-benzodiazepine. Brain Res 1987; 401:55-9. [PMID: 3815094 DOI: 10.1016/0006-8993(87)91163-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The blood-brain transport and regional distribution of a tritium-labeled, brominated benzodiazepine (BFB) was determined for the rat brain in vivo. The unidirectional transport constant from blood to brain was measured by a graphical, integral method and was found to be 0.83 ml/g/min, a value which indicates that transport is essentially flow-dependent. The apparent volume of distribution increased linearly during the measurement period, suggesting that back transport from brain to blood was zero and that BFB was trapped in the tissue, possibly by specific receptors or acceptors. Under the conditions of these experiments, autoradiography of brain tissue sections indicated a regional distribution of [3H]BFB similar to that expected for regional cerebral blood flow. These results indicate that BFB is a useful blood flow tracer in brain and suggest that BFB radiobrominated with bromine-75 may, under appropriate conditions, be a suitable tracer for in vivo regional blood flow measurement or benzodiazepine receptor mapping by positron-emission tomography.
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69
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Coenen HH, Laufer P, Stöcklin G, Wienhard K, Pawlik G, Böcher-Schwarz HG, Heiss WD. 3-N-(2-[18F]-fluoroethyl)-spiperone: a novel ligand for cerebral dopamine receptor studies with pet. Life Sci 1987; 40:81-8. [PMID: 2948091 DOI: 10.1016/0024-3205(87)90255-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
3-N-(2-[18F]-fluoroethyl)-spiperone [( 18F]-FESP) was synthesized at high specific activity by condensation with 2-[18F]-fluoroethyltosylate (35 TBq/mmol). In vivo binding studies in baboons by positron emission tomography exhibited regio-selective uptake in the striatum which was saturable with the cold ligand and prevented by pretreatment with (+)-butaclamol. The pharmacokinetic behaviour, i.e. the absolute uptake in tissue and the striatum-to-cerebellum ratio, was very similar to that of methylspiperone. Analysis of the radioactivity in mouse brain after administration of [18F]-FESP indicated a high in-vivo stability (greater than 90% after 210 min in the striatum). Comparative distribution studies of other N-fluoroalkylspiperones in mice suggest that FESP and the N-fluoropropyl analogue are the most potent D2 receptor ligands.
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70
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Coenen H, Pike V, Stöcklin G, Wagner R. Recommendation for a practical production of [2-18F]fluoro-2-deoxy-D-glucose. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0883-2889(87)90124-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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71
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Moerlein SM, Laufer P, Stöcklin G, Pawlik G, Wienhard K, Heiss WD. Evaluation of 75Br-labelled butyrophenone neuroleptics for imaging cerebral dopaminergic receptor areas using positron emission tomography. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1986; 12:211-6. [PMID: 2876896 DOI: 10.1007/bf00256924] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A comparative evaluation of three radiobrominated butyrophenone neuroleptics--bromospiperone (BSP), brombenperidol (BBP), and bromperidol (BP)--was made to assess the applicability of these compounds as radiopharmaceuticals labelled with the positron emitter 75Br (T1/2 = 1.6 h) for mapping cerebral dopaminergic receptor areas non-invasively with positron emission tomography (PET). BSP, BBP, and BP were prepared in high specific activities with high radiochemical yields, using electrophilic reactions with no-carrier-added 77Br- or 75Br-. Screening tests in rats using 77Br-labelled compounds indicated D2-specific localization for 77Br-BSP and 77Br-BBP, whereas PET experiments in baboons showed that only 75Br-BSP preferentially localized in cerebral tissues rich in dopaminergic receptors. The data suggest an inverse relationship between cerebral uptake and receptor-specific localization, which was attributed to a complicated interplay between the D2 receptor binding affinity, lipophilicity, % ionization and molecular weight of the radioligand, and the binding capacity of the cerebral tissues. 75Br-BSP gave a striatum-to-cerebellum ratio of 3 in baboon brain 5 h post-injection, which allowed visualization of dopaminergic-receptor-containing areas of the living brain using PET.
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72
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Moerlein SM, Stöcklin G, Pawlik G, Wienhard K, Heiss WD. Regional cerebral pharmacokinetics of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine as examined by positron emission tomography in a baboon is altered by tranylcypromine. Neurosci Lett 1986; 66:205-9. [PMID: 3487753 DOI: 10.1016/0304-3940(86)90191-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The selective dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has chemical and metabolic characteristics which allow its in vivo tissue distribution to be studied using positron emission tomography (PET). The cerebral pharmacokinetics of [11C]MPTP labelled at the N-methyl position was quantitatively traced in the living brain of an anesthetized baboon using PET, and the effect of administration of the monoamine oxidase (MAO) inhibitor tranylcypromine on this regional cerebral distribution was determined in the same animal. Following injection of [1C]MPTP, radioactivity rapidly concentrated in the basal ganglia of the primate's brain. This in vivo localization was prevented by prior administration of tranylcypromine, suggesting that it is oxidized metabolites of MPTP which are sequestered by dopaminergic neurons. Radioactivity rapidly localized preferentially in the basal ganglia of the primate brain, and this in vivo localization was blocked by prior administration of the MAO inhibitor tranylcypromine.
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73
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Hamacher K, Coenen HH, Stöcklin G. Efficient stereospecific synthesis of no-carrier-added 2-[18F]-fluoro-2-deoxy-D-glucose using aminopolyether supported nucleophilic substitution. J Nucl Med 1986; 27:235-8. [PMID: 3712040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
An aminopolyether mediated synthesis of fluorine-18 (18F) 2-fluoro-2-deoxy-D-glucose (FDG) has been developed. The nucleophilic fluorination with accelerator-produced [18F]fluoride works at the no-carrier-added level and gives epimerically pure 2-18FDG with an uncorrected radiochemical yield of a maximum 50% in a synthesis time of approximately 50 min from EOB.
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74
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Stöcklin G. Molecules labeled with positron emitting halogens. INTERNATIONAL JOURNAL OF RADIATION APPLICATIONS AND INSTRUMENTATION. PART B, NUCLEAR MEDICINE AND BIOLOGY 1986; 13:109-18. [PMID: 3533853 DOI: 10.1016/0883-2897(86)90225-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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75
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Vyska K, Magloire JR, Freundlieb C, Höck A, Becker V, Schmid A, Feinendegen LE, Kloster G, Stöcklin G, Schuier FJ. In vivo determination of the kinetic parameters of glucose transport in the human brain using 11C-methyl-D-glucose (CMG) and dynamic positron emission tomography (dPET). EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1985; 11:97-106. [PMID: 3876936 DOI: 10.1007/bf00265041] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A method was developed to measure simultaneously the rate constants for glucose influx and glucose efflux, and the Michaelis-Menten constant (KM) and maximal velocity (Vmax) for glucose transport across the blood-brain barrier (BBB) in any selected brain area. Moreover, on the basis of a mathematical model, the local perfusion rate (LPR) and local unidirectional glucose transport rate (LUGTR) are calculated in terms of parameters of the time-activity curves registered over different brain regions; 11C-methyl-D-glucose (CMG) is used as an indicator. The transaxial distribution of activity in the organism is registered using dynamic positron-emission tomography (dPET). The method was used in 4 normal subjects and 50 patients with ischemic brain disease. In normals, the rate constant for CMG efflux was found to be 0.25 +/- 0.04 min-1 in the cortex and 0.12 +/- 0.02 min-1 in white matter. In the cortex, the KM was found to be 6.42 mumol/g and the Vmax was 2.46 mumol/g per minute. The LUGTR ranged from 0.43 to 0.6 mumol/g per minute in the cortex, and from 0.09 to 0.12 mumol/g per minute in white matter. The LPR was calculated to be 0.80-0.98 ml/g per minute for the cortex and 0.2-0.4 ml/g per minute for white matter. In patients with stroke, the ischemic defects appeared to be larger in CMG scans than in computed x-ray tomography (CT) scans. Prolonged reversible ischemic neurological deficit was associated with a significant fall in the LUGTR but no change in the LPR in the corresponding cerebral cortex. Normal LUGTR and significantly decreased LPR were registered in a patient with progressive occlusion of the middle cerebral artery. In a patient with transient ischemic attacks, a slightly reduced LPR and a disproportionally reduced LUGTR were observed before operation. After extra- and intracranial bypass surgery, the LPR became normal, whereas the LUGTR increased but did not achieve normal values.
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76
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Linz U, Stöcklin G. Chemical and biological consequences of the radioactive decay of iodine-125 in plasmid DNA. Radiat Res 1985; 101:262-78. [PMID: 3975356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Doubly labeled [U-14C, 5-125I]iododeoxycytidine (IdC) triphosphate was synthesized and incorporated enzymatically into defined positions of the plasmid pBR322. After storage under various conditions, the stable end products were analyzed using radio-GC, radio-HPLC, and electron microscopy. In addition, solutions of 14C-IdC-labeled DNA containing Na125I as an internal radiation source were studied to investigate the influence of internal radiolysis. Transmutation of the covalently bound 125I leads to complete destruction of the labeled nucleotide, giving rise to 14CO2 and 14CO as major products. Fragmentation of the pyrimidine base is independent of solvent and DNA configuration. Internal radiolysis caused by Na125I leads to only minor damage. Electron microscopy studies reveal that decay-induced double strand breaks (dsb) occur both at the site of decay and in areas as far as hundreds of base pairs apart from that site. Number and distribution of the breaks is strongly dependent on solvent and DNA configuration. A direct correlation exists between the extent of fragmentation of the nucleotide and the mean number of dsb.
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77
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Linz U, Stöcklin G, Stocklin G. Chemical and Biological Consequences of the Radioactive Decay of Iodine-125 in Plasmid DNA. Radiat Res 1985. [DOI: 10.2307/3576393] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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78
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Moerlein SM, Laufer P, Stöcklin G. Effect of lipophilicity on the in vivo localization of radiolabelled spiperone analogues. INTERNATIONAL JOURNAL OF NUCLEAR MEDICINE AND BIOLOGY 1985; 12:353-6. [PMID: 3833821 DOI: 10.1016/s0047-0740(85)80003-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A series of N-alkylated and para-brominated analogues of spiperone were synthesized to ascertain the effect of lipophilicity on the in vivo localization of neuroleptics. While the IC50 for D2 receptor binding was within the same order of magnitude for these compounds, the calculated octanol-water partition coefficients varied 300-fold. When the in vivo distribution data for 77Br-labelled compounds were compared with previous data for 18F- and 11C-labelled analogues it was seen that the highest cerebral uptake was for bromospiperone, but the optimum striatum-to-cerebellum and brain-to-blood concentrations were achieved by N-methyl spiperone. The implications of these results for radiopharmaceutical design or medicinal chemistry are discussed.
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79
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Abstract
The in vivo binding of the radiobrominated neuroleptic brombenperidol in rat brain was studied. The accumulation of the radiolabeled neuroleptic was high in the striatum and relatively low in the cerebellum, cortex, and blood. Striatal binding of brombenperidol was saturable and displaced by subsequent administration of benperidol. The rationale for the development of 75Br-brombenperidol as a radiopharmaceutical for the non-invasive imaging of cerebral dopamine receptor areas is presented.
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80
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Kloster G, Stöcklin G, Smith EF, Schrör K. Omega-halofatty acids: a probe for mitochondrial membrane integrity. In vitro investigations in normal and ischaemic myocardium. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1984; 9:305-11. [PMID: 6468423 DOI: 10.1007/bf00276459] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Long-chain omega-halofatty acids, especially omega-123I-iodoheptadecanoic acid (IHA), are widely used clinically as radiopharmaceuticals for functional heart imaging. The metabolic interpretation of the various elimination rates, however, remains in dispute. It has been previously shown (Kloster and Stöcklin 1982) that in isolated perfused guinea-pig hearts halide diffusion from the mitochondrion to the blood is the rate-determining step of IHA pharmacokinetics in normal myocardium. We have now extended these in vitro experiments to normal and globally ischaemic isolated perfused rabbit hearts. Again, in normal hearts a single phase iodide elimination half-time (14.3 +/- 2.1 min) was observed. In hearts made globally ischaemic for 90 min, the iodide elimination was biphasic with a first fast phase (T 1/2 = 3.8 +/- 0.49 min) and a late slow phase (T 1/2 = 60.5 +/- 14.0 min). The first fast phase is attributed to iodide ion released by residual beta-oxidation (more rapid than in normal hearts due to damaged membranes in ischaemia), while the late slow phase is explained by beta-oxidation of IHA slowly released by hydrolysis of intracellular lipid stores. These data were compared with published data from investigations in patients which seem to support our interpretation.
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81
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Zaidi J, Qaim S, Stöcklin G. Excitation functions of deuteron induced nuclear reactions on natural tellurium and enriched 122Te: Production of 123I via the 122Te(d,n)123I-process. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0020-708x(83)90041-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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82
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Kloster G, Schrör K, Stöcklin G. Short-lived radioisotope techniques: a new potential tool for non-invasive clinical pharmacology. METHODS AND FINDINGS IN EXPERIMENTAL AND CLINICAL PHARMACOLOGY 1983; 5:533-6. [PMID: 6363839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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83
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Smith III E, Kloster G, Schrör K, Stöcklin G. Radioiodinated ω-halofatty acids: A probe for myocardial membrane integrity. J Mol Cell Cardiol 1983. [DOI: 10.1016/0022-2828(83)91061-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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84
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Scholl H, Kloster G, Stöcklin G. Bromine-75-labeled 1,4-benzodiazepines: potential agents for the mapping of benzodiazepine receptors in vivo: concise communication. J Nucl Med 1983; 24:417-22. [PMID: 6601698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We have prepared four different 1,4-benzodiazepines, labeled at C-7 with the 1.6-hr positron emitter Br-75 or the 57-hr gamma emitter Br-77, as potential radio-pharmaceuticals for the mapping of cerebral benzodiazepine receptor areas. The triazene method was used and optimized. Yields at the no-carrier-added level were 20%. 7-[75Br]-5-(2-fluorophenyl)-1-methyl-1,3-dihydro-2H-1,4-benzodiazepine-2-one (Br-75 BFB) was isolated with a minimum specific activity of 20,000 Ci/mmole. Biodistribution in mice shows that BFB is taken up rapidly by the brain and is retained there at useful concentrations for significant periods of time. The maximum uptake is observed at 0.25 min. Brain-to-blood concentration ratios are larger than 2 during the interval (0.25 to 10 min) investigated.
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85
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Kloster G, Laufer P, Wutz W, Stöcklin G. 75,77Br- and 123I-analogues of D-glucose as potential tracers for glucose utilisation in heart and brain. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1983; 8:237-41. [PMID: 6873102 DOI: 10.1007/bf00522512] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A number of D-glucose analogues labelled with either the positron emitter 75Br (T 1/2 = 1.6 h) or the single photon emitter 123I (T 1/2 = 13.3 h) were studied as potential tracers for glucose utilisation in heart and brain. Of these, 3-deoxy-3-bromo-D-glucose, 3-deoxy-3-iodo-D-glucose, methyl 2-deoxy-2-bromo-beta-D-glucoside and methyl 2-deoxy-2-iodo-beta-D-glucoside showed little uptake of radioactivity into brain and an unfavourable ratio of heart-to-blood and heart-to-lung concentrations. In contrast, methyl 3,4,6-tri-O-acetyl-2-deoxy-2-iodo-beta-D-glucoside (MTIG) and methyl 3,4,6-tri-O-acetyl-2-deoxy-2-bromo-beta-D-glucoside (MTBG) showed promising brain uptake (160% MBC for MTBG) with a good brain-to-blood concentration ratio of 0.8. MTBG is not metabolically altered in the brain. Thus, this compound may be a promising tracer for measuring glucose transport if it proves to be a substrate for the hexose carrier at the blood-brain-barrier.
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86
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Blessing G, Weinreich R, Qaim S, Stöcklin G. Production of 75Br and 77Br via the 75As(3He,3n)75Br and 75As(α,2n)77Br reactions using Cu3As-alloy as a high-current target material. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0020-708x(82)90145-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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87
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Youfeng H, Qaim SM, Stöcklin G. Excitation functions for 3He-Particle induced nuclear reactions on 76Se, 77Se and natSe: possibilities of production of 77Kr. THE INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES 1982; 33:13-9. [PMID: 7061158 DOI: 10.1016/0020-708x(82)90199-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Thin selenium films were prepared by cathodic deposition on aluminium foils. The Al-Se-Al sandwich stacks were used for measurement of the excitation functions of the 76Se(3He,2n)77Kr, 77Se(3He,3n)77Kr and natSe(3He,xn)77Kr reactions up to 3He-particle energy of 36 MeV. Excitation functions were also measured for the competing reactions 76Se(3H,3n)76Kr, 76Se(3He,pn)77Br, 76Se(3He,p2n)76Br, 76Se(3He,p3n)75Br, 76Se(3He, alpha)75Se, 77Se(3He,n)79Kr, 77Se(3He,4n)76Kr, 77Se(3He,pn)78Br, 77Se(3He,p2n)77Br, 77Se(3He,p3n)76Br, 77Se(3He, alpha n)75Se, natSe(3He,xn)79Kr and natSe(3He,xn)76Kr. Thick target yields were calculated for the formation of krypton and bromine isotopes in 3He-induced reactions on 76Se and 77Se and for krypton isotopes in reactions on natural selenium. The possibilities of production of 77Kr using 3He-particle induced reactions on 76Se, 77Se and natSe were investigated. From the viewpoint of yield and purity, for the production of 77Kr the reactions 76Se(3He,2n)77Kr and 77Se(3He,3n)77Kr were found to be very suitable, the former at low energies and the latter at relatively higher energies. In the case of 76Se(3He,2n)77Kr reaction, a target thickness corresponding to E3Hc = 25 leads to 15 MeV leads to a theoretical thick target yield of 7.5 mCi 77Kr/micro Ah; the 76Kr impurity at EOB amounts to 0.45%. In the case of 77Se(3He,3n)77Kr reaction, on the other hand, for a target thickness corresponding to E3Hc = 36 leads to 15 MeV the calculated thick target yield of 77Kr is 11.5 mCi/micro Ah and the levels of impurities 79Kr and 76Kr at EOB amount to 0.35 and 0.36% respectively.
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88
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Jahnke S, Stöcklin G, Willenbrink J. Translocation profiles of (11)C-assimilates in the petiole of Marsilea quadrifolia L. PLANTA 1981; 153:56-63. [PMID: 24276707 DOI: 10.1007/bf00385318] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/1981] [Accepted: 05/18/1981] [Indexed: 06/02/2023]
Abstract
An array of three multipliers with BGO-crystals arranged along the petiole has been used to study the movement of (11)C-assimilate in Marsilea quadrifolia L. The leaf blades were exposed to a 3-6 min pulse of (11)CO2 under continuous light. Data were recorded with 10-s counting intervals and corrected for background, sensitivity of detectors, and (11)C-decay. The speed of translocation could be obtained from the time difference between the straight lines of (11)C-increase monitored at different positions along the petiole. The speed was within the range of 60 to 150 cm h(-1). Cutting as well as cold treatment at definite locations on the petiole led to an immediate stop of (11)C-movement. Both inhibition and-in the case of chilling-restoration of translocation were detectable within minutes. When the assimilation chamber was flushed with nitrogen gas, the normal increase of (11)C at the monitored sites slowed down which, after prolonged N2-treatment, even resulted in a decrease. With a time-delay down the petiole, replacement of N2 by an air-stream led to complete restoration of the (11)C-slope. These and similar shortterm effects on translocation could not be detected by former methods. This technique is also useful in with species other than Marsilea qu., which was chosen as a test plant because of the anatomical 'simplicity' of its petiole.
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89
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Coenen HH, Harmand MF, Kloster G, Stöcklin G. 15-(p[75Br]bromophenyl)pentadecanoic acid: pharmacokinetics and potential as heart agent. J Nucl Med 1981; 22:891-6. [PMID: 7053078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Preparation, quality control, and pharmacokinetics of 15-(p-[75Br]bromophenyl)pentadecanoic acid (BPPA) were studied, with particular emphasis on the fate of the label and the usefulness of BPPA as a heart agent. BPPA labeled with the positron emitter Br-75 (T 1/2 = 98 min) was prepared in 55% radiochemical yield with a specific activity of greater than or equal to 1000 Ci/mmol. While the uptake of BPPA in the heart muscle is as fast and efficient as that of aliphatic omega-halofatty acids, its elimination is delayed, owing mainly to an inhibited beta oxidation and the formation of lipophilic catabolites. The blood activity and its time course are identical to those of omega-halofatty acids, but no free bromide appears in any body fluid or organ. The complex pharmacokinetic behavior of stable lipophilic catabolites prevents a quantitative background correction. In contrast to aliphatic omega-halofatty acids, a quantitative evaluation of myocardial metabolism is not possible. Br-75 BPPA, however, is well suited for positron emission tomography of the heart.
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90
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Deutzmann R, Stöcklin G, Stocklin G. Chemical Effects of Iodine-125 Decay in Aqueous Solution of 5-Iodouracil. Ring Fragmentation as a Consequence of the Auger Effect. Radiat Res 1981. [DOI: 10.2307/3575538] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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91
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Deutzmann R, Stöcklin G. Chemical effects of iodine-125 decay in aqueous solution of 5-iodouracil. Ring fragmentation as a consequence of the Auger effect. Radiat Res 1981; 87:24-36. [PMID: 6789368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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92
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Vyska K, Höck A, Freundlieb C, Becker V, Schmid A, Kloster G, Kloster G, Stöcklin G. [Studies of cardiac metabolism with 123I-labelled fatty acids and 11C-methylglucose (author's transl)]. Nuklearmedizin 1981; 20:148-55. [PMID: 6973145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
To characterize externally detectable changes in the myocardial metabolism of free fatty acids (FFA) and glucose, which are associated with ischemia and cardiomyopathy, omega-123I-heptadecanoic acid (stearic acid analogue), 75Br-phenylpentadecanoic acid, and 3-0-11C-methyl-D-glucose were used as indicators. It could be demonstrated that in the metabolism of free fatty acids at least two different patho-physiological situations may exist. Disturbances in the mechanism of the accumulation of free fatty acids lead to a decrease of the amount of the free fatty acids which are available for energy production (these disturbances can be recognized as indicator accumulation defects). Disturbances associated with the mechanism of free fatty acid catabolism lead to a decrease of the ability of the myocardial cell to utilize the free fatty acids (these disturbances can be recognized as changes in indicator elimination rates). Whereas in ischaemic heart disease, the areas with altered FFA accumulation correlate with the areas of altered FFA-elimination, no correlation was found in the case of cardiomyopathy. The 11C-methylglucose seems to be an excellent indicator for the in-vivo assessment of the function of transport system in the myocardial cell membrane.
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93
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Feinendegen LE, Vyska K, Freundlieb C, Höck A, Machulla HJ, Kloster G, Stöcklin G. Non-invasive analysis of metabolic reactions in body tissues, the case of myocardial fatty acids. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1981; 6:191-200. [PMID: 7250136 DOI: 10.1007/bf00290563] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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94
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Höck A, Freundlieb C, Becker V, Schmid A, Feinendegen LE, Kloster G, Stöcklin G, Vyska K. Stoffwechseluntersuchung am Herzen mit 123J-Fettsäuren und 11C-Methylglukose. Nuklearmedizin 1981. [DOI: 10.1055/s-0037-1620731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Um die extern erfaßbaren Veränderungen im myokardialen Stoffwechsel der freien Fettsäuren und der Glukose bei Ischämie und Kardiomyopathie zu charakterisieren, wurde ω-123J-Heptadekansäure (Stearinsäure-Analog), 75Br-Phe-nylpentadekansäure und 3–0–11C-Methyl-D-Glucose als Indikatoren benutzt. Es konnte gezeigt werden, daß mindestens zwei unterschiedliche pathophysiologische Situationen im Stoffwechsel der freien Fettsäuren existieren können. Durch die Störungen der Akkumulationsmechanismen ist die Verfügbarkeit der freien Fettsäuren für die Energieproduktion im Myokard reduziert (diese Störungen werden als Änderungen in der Indikatorakkumulation erkannt). Durch die Störungen der Abbaumechanismen der Fettsäuren wird die Fähigkeit der myokardialen Zelle, die freien Fettsäuren zu verwerten, reduziert (diese Störungen werden als Veränderungen in den Indikatoreliminationsraten erkannt). Im Gegensatz zur koronaren Herzerkrankung konnte bei Kardiomyopathie keine Korrelation zwischen Bereichen veränderter Indikatorakkumulation und pathologischer Indikatoreliminationsraten gefunden werden. Die 11C-Methylglukose erwies sich als ein sensitiver Indikator, der die in-vivo-Beurteilung des Zustandes der Zellmembran-gebundenen Transportsysteme ermöglicht.
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95
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Knust E, Kupfernagel C, Müller-Platz C, Stöcklin G. Synthesis and quality control of aliphatic and aromatic 18F-labelled compounds for probing metabolism in-vivo. J Fluor Chem 1980. [DOI: 10.1016/s0022-1139(00)84059-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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96
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Freundlieb C, Höck A, Vyska K, Feinendegen LE, Machulla HJ, Stöcklin G. Myocardial imaging and metabolic studies with [17-123I]iodoheptadecanoic acid. J Nucl Med 1980; 21:1043-50. [PMID: 7431103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
After intravenous administration of the stearic acid analogue [17-123I]iodoheptadecanoic acid (I-123 HA), myocardial metabolism was studied in ten normal individuals, eight patients with coronary artery disease and three patients with congestive heart failure. High-quality images were obtained in sequential scintigraphy of I-123 metabolically bound in myocardial tissue. Infarcted zones as well as ischemic regions are indicated by reduced tracer uptake. Iodine-123 in the blood pool and interstitial space consists mainly of radioiodide that is liberated by fatty-acid metabolism and was corrected for. Using the proposed correction not only are the images improved but the uptake and elimination of the I-123 in the myocardial cells can be followed. The average disappearance half-time of I-123 HA from the myocardium of normal persons was 24 +/- 4.7 min. In patients with coronary artery disease significant differences between myocardial regions were observed.
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97
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Knust EJ, Kupfernagel C, Stöcklin G. Long-chain F-18 fatty acids for the study of regional metabolism in heart and liver; odd-even effects of metabolism in mice. J Nucl Med 1979; 20:1170-5. [PMID: 317095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In view of the potential usefulness of fluorine-tagged fatty acids in the study of regional metabolism in the heart and liver, the time courses of uptake and release of 9,10-[18F]fluorostearic acid, 2-[18F]fluorostearic acid, 16-[18F]fluorohexadecanoic acid, 17-[18F]fluoroheptadecanoic acid have been investigated in several organs of NMRI mice. Whereas 2-[18F]fluorostearic acid shows very little uptake in the heart muscle but an increasing accumulation in the liver, the fatty acids with the F-18 label in the middle or at the end of the carbon chain exhibit uptake and elimination behavior similar to that of the analogous C-11-labeled compounds. After rapid concentration in the heart within 1 min, clearance takes place with fast and slow components. 16-[18F]fluorohexadecanoic acid and 17-[18F]fluoroheptadecanoic acid have different half-times of elimination. These differences are also reflected by the fact that nearly all the activity present in the heart can be recovered as fluoride(F-18) in the case of 17-[18F]fluoroheptadecanoic acid, whereas practically no fluoride was found among the metabolites of 16-[18F]fluorohexadecanoic acid. Similar differences were observed for the F-18 activity in bone. The results can be interpreted in terms of the odd-even rule: beta oxidation of even-numbered fatty acids ends up with [18F]fluoroacetic acid, whereas the odd-numbered fatty acids give rise to beta-[18F]fluoropropionic acid. Only in the latter case does dehalogenation take place leading to free fluoride, whereas fluoroacetic acid undergoes further reactions in the citric acid cycle.
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98
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Tisljar U, Kloster G, Ritzl F, Stöcklin G. Accumulation of radioiodinated L-alpha-methyltyrosine in pancreas of mice: concise communication. J Nucl Med 1979; 20:973-6. [PMID: 536844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
L-3-iodo-alpha-methyltyrosine, labeled with either I-131 or I-123, has a high pancreatic specificity in mice. A pancreas-to-liver ratio of 8.6 +/- 2.7 is observed during the first hour after i.v. injection. Accumulation is also prominent in the kidneys, but excretion of the radioagent is rapid, 50% of the activity being eliminated during 90 min. Compared with L-[75Se]selenomethionine, the compound currently used for pancreatic imaging, L-3-[123I]or[131I]iodo-alpha-methyltyrosine has a higher pancreas-to-liver ratio, a shorter physical half-life and biological half-time, and better decay characteristics.
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100
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Machulla HJ, Stöcklin G, Kupfernagel C, Freundlieb C, Höck A, Vyska K, Feinendegen LE. Comparative evaluation of fatty acids labeled with C-11, Cl-34m, Br-77, and I-123 for metabolic studies of the myocardium: concise communication. J Nucl Med 1978; 19:298-302. [PMID: 632908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Various long-chain fatty acids have been labeled with C-11, Cl-34m, Br-77, and I-123 and evaluated for their potential application in measuring myocardial metabolism in vivo. Comparative studies of the kinetics of accumulation and clearance from the heart muscle of mice indicate that the extraction of omega-halofatty acids is more efficient than that of alpha-halofatty acids. Among the omega-halofatty acids, the highest uptake is observed for the 17-iodoheptadecanoic acid, which shows an extraction behavior almost identical to that of [1-11C] palmitic acid, although with a higher radioactivity level in blood due to the release of free iodide.
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