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Involved institute: Institute of Radiopharmacy
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Gesamtzahl lt. Auswahl: 1223 Title records (100 Title records je Seite)

1629 Publications

3D QSAR study, synthesis and in vitro evaluation of (+)-5-FBVM as potential PET radioligand for the Vesicular AcetylCholine Transporter (VAChT)
Kovac, M.; Mavel, S.; Deuther-Conrad, W.; Méheux, N.; Glöckner, J.; Wenzel, B.; Anderluh, M.; Brust, P.; Guilloteau, D.; Emond, P.
Abstract: Located in presynaptic cholinergic nerve terminals, the vesicular acetylcholine transporter (VAChT) represents a potential target for quantitative visualization of early degeneration of cholinergic neurons in Alzheimer´s disease using PET. Benzovesamicol derivatives are proposed as radioligands for this purpose. We report QSAR studies of vesamicol and benzovesamicol derivatives taking into account the stereoselectivity of the VAChT binding site. Use of different data sets and different models in this study revealed that both enantiomers of 5-fluoro-3-(4-phenyl-piperidin-1-yl)-1,2,3,4-tetrahydro-naphthalen-2-ol (5-FBVM) are promising candidates, with predicted VAChT affinities between 6.1 and 0.05 nM. The synthesis of enantiopure (R,R)- and (S,S)-5-FBVM and their corresponding triazene precursors for future radiofluorination is reported. Both enantiomers exhibited high in vitro affinity for VAChT [(+)-5-FBVM: Ki = 6.95 nM and (-)-5-FBVM: Ki = 3.68 nM] and were selective for s2 receptors (~70-fold), only (+)-5-FBVM is selective for s1 receptors (~5-fold). These initial results suggest that (+)-(S,S)-5-FBVM warrants further investigation as a potential radioligand for in vivo PET imaging of cholinergic nerve terminals.
Keywords: Benzovesamicol derivative; VAChT; triazene; fluoro-dediazoniation, 3D QSAR

Bioorganic & Medicinal Chemistry (2010)

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Registration 27.08.2010 12:07, No. 14449

[18F]NS10743: Characterisation Of A Selective a7 Nicotinic Acetylcholine Receptor (a7 nAChR) Radioligand In Pig Brain By PET
Deuther-Conrad, W.; Fischer, S.; Hiller, A.; Funke, U.; Østergaard Nielsen, E.; Brunicardi Timmermann, D.; Steinbach, J.; Peters, D.; Brust, P.
Abstract: Introduction: Alterations of a7 nAChR have been observed in schizophrenia, brain trauma and neurodegenerative diseases. For PET imaging of a7 nAChR [18F]NS10743 has been successfully developed evaluated in mice by tissue distribution and specificity studies. Here we report on baseline and blocking PET studies with [18F]NS10743 in pig brain.
Methods: [18F]NS10743 was synthesized with high specific activity (>150 GBq/μmol) and radiochemical purity (>99%). Dynamic PET scanning was performed in anaesthetized female piglets (13-15 kg), intravenously injected with ~ 330 MBq [18F]NS10743 (total mass ~ 472 ng) for 120 min. Three animals additionally received 3 mg/kg of the a7 nAChR partial antagonist NS6740 at 10 min pre-tracer injection followed by a continuous infusion (1 mg/kg/h). Plasma samples were taken and metabolite-corrected input functions were estimated. Individual regions of interest were defined using an MRI-based template of pig brain. SUV and distribution volume (VT = K1/k2) were estimated. The ratio of specifically bound radioligand and non-displaceable radioligand in brain tissue was calculated from the VT values by BPND = (VT region - VT reference)/VT reference.
Results: [18F]NS10743 readily passed the blood-brain barrier and the uptake of radioactivity peaked with SUV = 2.23 ± 0.71 at 8 min in the baseline scan while in NS6740-blocking studies the radioactivity levels peaked significantly earlier (SUV = 3.02 ± 1.28 at 5 min) and decreased faster. At the end of study (between 90 and 120 min p.i.) SUV was significantly decreased by NS6740 in allinvestigated brain regions except olfactory bulb, which was chosen as reference region for calculation of BPND. At baseline, a VT value of 6.07 ± 1.54 was estimated for the whole brain with the highest radiotracer accumulation in the temporal, parietal, and occipital lobe, thalamus, striatum, and middle cortex (VT = 7.27 ± 1.95 – 7.10 ± 1.58). Intermediate binding was observed in hippocampus, colliculi, midbrain, frontal lobe, and ventral cortex (VT = 6.76 ± 1.71 – 6.09 ± 1.05), and lowest values were assessed in the cerebellum, pons, and olfactory bulb (VT = 5.71 ± 1.18 – 4.11 ± 0.96). Baseline BPND values for high (temporal lobe), median (hippocampus) and low specific binding (cerebellum) were 0.76 ± 0.07, 0.54 ± 0.08, and 0.39 ± 0.08, respectively. NS6740 significantly reduced the binding potential BPND in regions with high [18F]NS10743 binding (temporal lobe: -29 %, p = 0.01; midbrain: -35 %, p = 0.02) while the decrease in regions with low binding was not significant (cerebellum: -16 %, p = 0.2).
Conclusion: These data make [18F]NS10743 a reasonable candidate for further development of in vivo a7 nAChR imaging by PET. The challenge to improve the binding potential of [18F]NS10743, limited mainly by the low density of a7 nAChR expression in the brain and reflected by rather small regional differences in baseline uptake of [18F]NS10743, will be met by further modifications of the NS10743 core structure intended to increase the target affinity of the tracer compound.
the target affinity of the tracer compound.
Keywords: [18F]NS10743; a7 nAChR; PET

Lecture (Conference):
NRM2010 (Neuroreceptor Mapping Congress), 22.-24.07.2010, Glasgow, Großbritannien
Conference abstract in ref. journal:
NeuroImage 52(2010)1

Registration 20.08.2010 12:24, No. 14418

A new hexanuclear rhenium cluster complex with six terminal acetate ligands: Synthesis, structure, and properties of K₄[Re₆S₈(CH₃COO)₆]·8H₂O
Brylev, Konstantin A.; Mironov, Yuri V.; Fedorov, Vladimir E.; Kim, S.-J.; Pietzsch, H.-J.; Stephan, H.; Ito, A.; Kitamura, N.
Abstract: A room-temperature reaction between [Re₆S₈(OH)₆]⁴⁻ and acetic acid in an aqueous solution resulted in the substitution of all terminal hydroxo groups by acetate ligands, affording a new hexanuclear anionic rhenium cluster complex [Re₆S₈(CH₃COO)₆]⁴⁻. The complex was isolated as a potassium salt with the composition of K₄[Re₆S₈(CH₃COO)₆]·8H₂O (1) and characterized by X-ray single-crystal diffraction and elemental analyses, IR, ¹H NMR, UV–Vis, and luminescence spectroscopies.
Keywords: Synthesis; Cluster compounds; Rhenium; Carboxylate ligands; Luminescence

Inorganica Chimica Acta 363(2010)11, 2686-2691

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Registration 19.08.2010 08:50, No. 14409

Novel ^99mTc ‘4 + 1’ peptide conjugates: Tuning the biodistribution by variation of coligands
Künstler, J.-U.; Seidel, G.; Bergmann, R.; Gniazdowska, E.; Walther, M.; Schiller, E.; Decristoforo, C.; Stephan, H.; Haubner, R.; Steinbach, J.; Pietzsch, H.-J.
Abstract: A sophisticated coligand strategy is presented for peptide-derived radioconjugates based on ^99mTc ‘4 + 1’ mixed-ligand complexes. The new pharmacologically active coligands are assessed for ^99mTc-labeling of the RGD-peptide cyclo(Arg-Gly-Asp-D-Tyr-Lys) which is an established vehicle to target a_vß₃ integrins playing a crucial part in tumor pathogenesis.
Complexes of the general formula [^99mTc(NS₃R)X] were synthesized and evaluated, in which Tc(III) is coordinated by NS₃R, a derivative of the tetradentate chelator 2,2´,2´´-nitrilotriethanethiol (NS₃), and by X, a monodentate binding isocyanide bearing the biomolecule. The novel tetradentate chelators (NS₃R = NS₃crown, NS₃en, NS₃(COOH)₃) constitute NS₃ with a crown ether, an amine or a tricarboxylic acid as pharmacological modifiers. The isocyanides (X = L2-RGD, L2-Lys) contained the linker isocyanobutanoic acid (L2) coupled to N⁶-Lys of the RGD-peptide and additionally to a single Lys.
The lipophilicity (distribution coefficient log D_O/W, pH = 7.4) of the RGD-containing radiotracers decreased in the order of the coligands NS₃crown (-1.7 +/- 0.1), NS₃en (-2.7 +/- 0.1) and NS₃(COOH)₃ (-3.3 +/- 0.1). In the same order of the coligands, the biodistribution of the series [^99mTc(NS₃R)(L2-RGD)] in normal rats showed a decrease of hepatobiliary and an increase of urinary excretion.
The ratio of specifically to unspecifically uptaken activity (sum of surface bound and internalized activity) in a_vß₃ integrin-expressing M21 cells was in the range of approximately 4-5 and comparable for all [^99mTc(NS₃R)(L2-RGD)] tracers. The biodistribution of [^99mTc(NS₃en)(L2-RGD)] in v/v mice bearing M21 and M21L (control) tumor xenografts exhibited a specific tumor uptake with a low target-background ratio.
The metabolic stability of the [^99mTc(NS₃R)(L2-RGD)] tracers in normal rats was high, since 75-87% of the radioactivity in the plasma extract was assigned to the injected radiotracers 60 min after intravenous
application in a rat. The hypothetical metabolites [^99mTc(NS₃R)(L2-Lys)] were not found.
These results demonstrate a considerable improvement of in vivo properties of ^99mTc ‘4 + 1’ peptide conjugates and open up the possibility of applying the labeling approach for further radiodiagnostic peptides.
Keywords: Technetium; ‘4 + 1’ Mixed-ligand complex; Peptide; RGD

European Journal of Medicinal Chemistry 45(2010), 3645-3655

Registration 18.08.2010 16:36, No. 14407


Cancer Research - Biennial Scientific Report 2007-2008 / Volume 2 Bohnet, C.; Bartho, A. (Editors) Wissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-508 2010 Downloads: 1,9 MB PDF Registration 18.08.2010 13:24, No. 14404


Radiolabeled Compounds in Analytics and Medicine Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Kolloquium University of Zurich, 01.07.2010, Zürich, Schweiz Registration 21.07.2010 11:10, No. 14308


Starch Coated Magnetic Nanoparticles With Pendant Chelating Agents Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Nanosight User Workshop “Nanoparticle Measurement”, 22.-23.06.2010, Langen, D Registration 21.07.2010 11:06, No. 14307


Emerging Opportunities for Application of Nanomaterials in Nuclear Medicine Stephan, H. Abstract: kein Abstract verfügbar Lecture (Conference): 7th SUPRAPHONE Meeting, 28.04.-01.05.2010, Maria Laach, D Registration 21.07.2010 11:02, No. 14306

Eph Receptors and Ephrin Ligands: Important Players in Angiogenesis and Tumor Angiogenesis
Mosch, B.; Reissenweber, B.; Neuber, C.; Pietzsch, J.
Abstract: Eph receptors and their ephrin ligands were identified in the late 1980's. Subsequently, they were linked to different physiological and pathophysiological processes like embryonic development, angiogenesis, and tumorigenesis. In this regard, recent work focused on the distribution and effects of Eph receptors and ephrins on tumor cells and tumor microenvironment. The purpose of this review is to outline the role of these molecules in physiological angiogenesis and pathophysiological tumor angiogenesis. Furthermore, novel therapeutical approaches are discussed as Eph receptors and ephrins represent attractive targets for antiangiogenic therapy.

Journal of Oncology 2010(2010), 135285

Registration 21.07.2010 09:36, No. 14301

Cyclin-Dependent Kinase 4/6 (Cdk4/6) Inhibitors: Perspectives in Cancer Therapy and Imaging
Graf, F.; Mosch, B.; Koehler, L.; Bergmann, R.; Wuest, F.; Pietzsch, J.
Abstract: Cyclin-dependent kinases 4 and 6 (Cdk4/6) are important components of cell cycle activation and control in early G₁ phase. Both enzymes and their regulators, e.g., cyclins, play critical roles in embryogenesis, homeostasis, and cancerogenesis. Cdk4/6 are attractive targets for cancer treatment. Recently, numerous selective small molecule inhibitors of Cdk4/6 have been developed. The potential of Cdk4/6 inhibitors, particularly, pyrido[2,3-d]pyrimidine derivatives, as both anti-cancer drugs and ¹²⁴I- and ¹⁸F-radiolabeled tracers for cancer imaging using positron emission tomography is discussed.

Mini-Reviews in Medicinal Chemistry 10(2010), 527-539

Registration 20.07.2010 15:38, No. 14298

The impact of hypoxia on gene expression and protein synthesis of Eph receptors and ephrin ligands in human melanoma cells
Reißenweber, B.; Mosch, B.; Pietzsch, J.
Abstract: Background
The transmembrane Eph receptors (Eph) and their ephrin ligands represent the largest subfamily of receptor tyrosine kinases. Eph/ephrins are key players in cell-cell communication due to their capability of bidirectional signaling. There is evidence that Eph/ephrins also play an important role in tumor progression and metastasis. Since hypoxia is an important elicitor for metastatic behaviour of tumor cells, the aim of our study was to investigate the influence of hypoxia on Eph and ephrin expression in primary and metastatic melanoma cell lines.

Materials and methods
The influence of experimental hypoxia (6 to 72 h) on viability and metabolism of three melanoma cell lines (Mel-Juso, A375, and A2058) was characterized using MTT tests and cellular uptake of both ¹⁸F-fluoromisonidazole (FMISO) and ¹⁸F-fluorodeoxyglucose (FDG). The mRNA expression of EphA2, EphB4, ephrinA1 and ephrinB2 was analyzed with quantitative RT-PCR. Protein synthesis was determined by flow cytometry.

Results
The uptake of FMISO increased in all three melanoma cell lines after incubation under hypoxic conditions. The FDG uptake under hypoxic conditions decreased in all three cell lines. The MTT test demonstrated that viability of A375 cells decreased to 29±3% after 72 h of hypoxia. A2058 cells showed only a weak decrease of viability by approximately 30%, whereas viability of Mel-Juso cells under hypoxia was not influenced. In all cells Eph/ephrin gene expression under hypoxic and normoxic conditions showed only minor differences, except for EphA2 expression in A375 cells, which increased by >40% after 12 h hypoxia. Flow cytometry showed no alteration in ephrin ligands under hypoxic conditions. In contrast, after 72 h hypoxia we detected a slight increase in EphB4 protein in all melanoma cell lines, and enhanced EphA2 protein only in metastatic cell lines A375 and A2058.

Conclusion
The metastatic melanoma cell lines A375 and A2058 react more sensitive to hypoxic conditions than the primary melanoma cell line Mel-Juso. Experimental hypoxia increases Eph receptor gene expression and protein synthesis, particularly, in metastatic melanoma cell lines, which could be indicative for a further mechanism by which hypoxia affects tumor metastasis.

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 119

Registration 20.07.2010 10:33, No. 14294

Synthesis and SERT Binding Properties of 5-Fluoroindol-3-yl cyclobutylamines
Scheunemann, M.; Steinbach, J.
Abstract: Several mental diseases are associated with disorders of the serotonergic neurotransmission.[1] The serotonin transporter (SERT) regulates the synaptic concentration of this neurotransmitter and represents a primary target in the development of antidepressant drugs. Indol-3-yl-cyclo-alkanyl/-alkenyl amines (CnH2n-2(4), n=6,5,3), considered as conformationally constrained analogues of 5-hydroxytryptamine (5-HT, serotonin), have been introduced as a class of candidates holding highly potent SERT inhibitors[.2] In the search for new SERT ligands for PET with improved binding profiles we turned our interest towards rigid structures containing a 1,3-disubstituted cyclobutane (CnH2n-2, n=4), as spacer between the indole moiety and the amino group.
The present work describes our work on the synthesis and biological evaluation of the mono-fluorinated (2a,3a,4a) and double-fluorinated target molecules (1 b,2b).
The carbonyl group of both 3-(2-benzyloxy-ethyl)- and 3-(3-benzyloxy-propyl)cyclobutanone was converted by appropriate steps to yield the N-methyl, N-Boc protected cis- or trans-cyclobutyl amines. After removing the O-benzyl group, the alcohol was oxidized to the aldehyde applying the known TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) procedure. The secondary amines (1a-4a) were then directly obtained from the cyclobutyl aldehyde precursor via Fischer indole synthesis; for the tertiary amines 1 b and 2b an N-alkylation of 1 a and 2a with 3-fluoropropyliodide was performed.
Displacement experiments on hSERT-HEK293 cells labeled with [3H]citalopram have shown that cis-derivatives (Ki values: 1 b, 6.74±0.79 nM; 2a, 5.43±0.54 nM; 2b, 6.31 ±1 .37 nM) have nanomolar affinity for human SERT. The trans compound shows somewhat lower affinity (3a, 10.7±1.88 nM). By contrast, parallel studies applying [3H]paroxetine as radioligand indicated significantly lower SERT affinities [90 nM < Ki (1 b,2a,2b,3a,4a) <155 nM]. Thus, potential radiotracers based on the new derivatives may be able to selectively label the citalopram binding site of the SERT.
We have developed a general access to 5-fluoroindol-3-yl cyclobutylamines both in cis(1a, 1b, 2a, 2b) and trans-configuration (3a, 4a) obtained from readily accessible starting materials. Five synthesized compounds (1b, 2a, 2b, 3a, 4a) displayed promising affinities for SERT.
Keywords: SERT; cyclobutylindole

Poster:
Frontiers in Medicinal Chemistry, 14.-17.03.2010, Münster, Germany

Registration 19.07.2010 15:17, No. 14291

High regiocontrol in the nucleophilic ring opening of 3-aralkyl-7-oxa-3-aza-bicyclo[4.1.0]heptanes with aliphatic and aromatic amines – A new short-step synthesis of FBT (4-fluorobenzyltrozamicol)
Scheunemann, M.; Steinbach, J.
Abstract: The 3,4-disubstituted piperidine framework plays an important role in many fields of pharmaceutical research[1] The ring opening of a conformationally rigid oxirane, annelleted to an N-protected six membered piperidine by an amine nucleophile, is a powerful method for establishing a trans-beta-aminoalcohol at the 3,4-position. Compounds derived from azavesamicol (trozamicol), which have been reported as usefulligands for the vesicular acetylcholine transporter (VAChT),[2] are displaying a 3-amino-piperidin-4-ol as a consistent structural feature. As part of our efforts in the search for new VAChT ligands for F18-PET (positron emission tomography) we have found a regioselective ring opening approach applying 3-(4-fluorobenzyl)-7-oxa-3-azabicyclo[4.1.0]heptane, which was utilized for a new 4-step synthesis of 4-fluorobenzyltrozamicol.
In contrast to former methodology, processing a common acyl[3] or carbamoyl[4] protective group at the piperidine nitrogen, we choose an N-benzyl protection. Starting from pyridine, which was converted to an N-4-fluorobenzylpyridinium salt, we obtained the corresponding N-protected 1,2,3,6-tetrahydropyridine via a standard hydrogenation using NaBH4 in EtOH. It was possible to epoxidize the olefine in high yield without interfering the basic tertiary amine, if applying trifluoroacetic acid in combination with its anhydride and H2O2-urea. As expected, the LiCIO4 assisted reaction of 1-aralkyl-3,4-epoxypiperidines with a series of aliphatic and aromatic amines in acetonitril led to a regioselective attack at position 4 of the piperidine to obtain 1-aralkyl-4-amino-piperidin-3-ol.[5] However, if applying EtOH as a protic solvent, without a coordinating Li-cation as additive, the inverse reg ioselectivity was observed. In this case, 1-aralkyl-3-aminopiperidin-4-oIs were derived as main products from the cleavage of the epoxy C-O bond at position 3. Following these protocols the aminoalcohol products were obtained as pure compounds by simple work-up without the need of chromatographic
separation.
In summary, we present an efficient method for the preparation of 3-amino-4-hydroxypiperidines and its regioisomers in 4-steps. The highly VAChT affine 4-fluorobenzyltrozamicol was obtained in an overall yield of 35%.
Keywords: VAChT; epoxide ring opening; 4-fluorobenzyltrozamicol; FBT

Poster:
Frontiers in Medicinal Chemistry, 14.-17.03.2010, Münster, Germany

Registration 19.07.2010 14:46, No. 14290

Synthesis and biological evaluation of a radioiodinated spiropiperidine ligand as a potential σ1 receptor imaging agent
Chen, R.-Q.; Li, Y.; Zhang, Q.-Y.; Jia, H.-M.; Deuther-Conrad, W.; Schepmann, D.; Steinbach, J.; Brust, P.; Wuensch, B.; Liu, B.-L.
Abstract: We report the synthesis and evaluation of 1'-(4-[125I]iodobenzyl)-3H-spiro[isobenzofuran-1,4'-piperidine] ([125I]Spiro-I) as a potential SPECT tracer for imaging of σ1 receptors. [125I]Spiro-I was prepared in 55–65% isolated radiochemical yield, with radiochemical purity of >99%, via iododestannylation of the corresponding tributyltin precursor. In receptor binding studies, Spiro-I displayed low nanomolar affinity for σ1 receptors (σ1: Ki = 2.75 ± 0.12 nM; σ2: Ki = 340 nM) and high subtype selectivity (σ2/σ1 = 124). Biodistribution in mice demonstrated relatively high concentration of radioactivity in organs known to contain σ1 receptors, including the lung, kidney, heart, spleen, and brain. Administration of haloperidol 5 min prior to injection of [125I]Spiro-I significantly reduced the concentration of radioactivity in the above-mentioned organs. These findings suggest that the binding of [125I]Spiro-I to σ1 receptors in vivo is specific.
Keywords: σ1 receptor; spiropiperidine; Iodine-125

Journal of Labelled Compounds and Radiopharmaceuticals (2010)

Registration 15.07.2010 15:04, No. 14276


Positron Emission Tomography (PET): Basic Principles of Radiotracer Design and Evaluation Brust, P. Abstract: Es ist kein Abstract vorhanden. Lecture (others): Kolloquium MPI Leipzig, 19.04.2010, Leipzig, Germany Registration 15.07.2010 14:09, No. 14274


Phenyl-HPLC-Säulen als hochselektive RP-Phasen zur Trennung aromatischer Verbindungen Wenzel, B. Abstract: Es ist kein Abstract vorhanden. Lecture (others): 3. HPLC-Workshop "Möglichkeiten und Grenzen der HPLC in den Lebenswissenschaften", 29.01.2010, Rossendorf, Germany Registration 15.07.2010 14:00, No. 14273

Design, Synthesis and in Vitro Biological Evaluation of Reference Compounds of 123I and 99Tcm Labeled Indole Radiotracers for σ2 Receptor Imaging
in Chinese
Li, Y.; Jia, H.-M.; Deuther-Conrad, W.; Brust, P.; Steinbach, J.; Liu, B.-L.
Abstract: Novel indole radiotracers for 123I and 99Tcm labeling were designed. The corresponding reference compounds (Indole-I and Indole-MAMA-Re) and the precursor for 99Tcm labelling were synthesized. The compounds were characterized by IR, NMR, and MS analyses. Competition binding assays in vitro show that the Ki values of Indole-I for σ1 and σ2 receptors are (0.574 ± 0.355) μmol/L and (0.162 ± 0.030 2) μmol/L, respectively. The Ki values of Indole-MAMA-Re for σ1 and σ2 receptors are (3.75 ± 2.22) μmol/L and (7.83 ± 4.87) μmol/L, respectively. Furthermore, 99Tcm-Indole-MAMA was successfully prepared. The radio-chemical purity (RCP) of 99Tcm-Indole-MAMA after purification was higher than 90% by HPLC analysis. The compounds reported in this paper may be used as lead compounds for further structural modification to develop indole SPECT tumor imaging agents.
Keywords: Indole; σ receptors; 99Tcm; 123I

Journal of Nuclear and Radiochemistry 32(2010)2, 132-138

Registration 15.07.2010 13:29, No. 14272

Interaction of ephrinB2 with its receptors EphB4 and EphB6 – potential impact on tumor-associated inflammation in human melanoma
Neuber, C.; Mosch, B.; Mamat, C.; Pietzsch, J.
Abstract: Background
Tumor-associated inflammatory cells (TAIC) are a major component of the tumor microenvironment and can contribute to both tumor progression and metastasis for instance by direct cell-cell interaction via membrane-bound proteins. Tumor cells show varying expression of Eph receptors and their ephrin ligands, which both are receptor tyrosine kinases. Eph/ephrins are hypothesized to be possible mediators of tumor-associated inflammation. The aim of our study was to analyze the distribution of ephrinB2 and its receptors EphB4 and EphB6 in inflammatory and melanoma cells and to clarify proinflammatory effects due to Eph/ephrin-mediated cell-cell contact.

Material and Methods
HL-60 promyelocytes and THP-1 monocytes, differentiated into granulocytes and macrophages, were used as a model for TAIC. Undifferentiated and differentiated cells were co-cultivated with Mel-Juso and A2058 melanoma cells. EphrinB2, EphB4 and EphB6 mRNA expression and protein synthesis was investigated using qRT-PCR and flow cytometry. Secretion of the proinflammatory cytokines IL-6 and TNF-α was analyzed using ELISA.

Results
No alteration in gene expression of ephrinB2, EphB4 and EphB6 could be observed during differentiation of HL-60 and THP-1 cells. In contrast, protein synthesis of ephrinB2, EphB4 and EphB6 was two- to threefold higher in HL-60 granulocytes compared to HL-60 promyelocytes and HL-60 macrophages. THP-1 macrophages showed a slightly increased protein synthesis of EphB4 and EphB6 compared to THP-1 monocytes whereas ephrinB2 protein content remained constant. Co-culture of both THP-1 monocytes and macrophages with Mel-Juso cells caused a substantial increment in secretion of proinflammatory cytokines. Co-culture of both HL-60 granulocytes and THP-1 monocytes with A2058 cells did not affect cytokine secretion. By contrast, co-culture of HL-60 macrophages with A2058 cells resulted in increased IL-6 secretion whereas co-culture of THP-1 macrophages with A2058 cells resulted in increased IL-6 secretion but decreased TNF-α release.

Conclusions
To our knowledge, mRNA expression and protein synthesis of ephrinB2, EphB4 and EphB6 was investigated for the first time in undifferentiated and differentiated HL-60 and THP-1 cells and, moreover, in Mel-Juso and A2058 melanoma cells. Co-culture of TAIC with melanoma cells resulted in proinflammatory effects. To differentiate the role of various Eph receptors and ephrin ligands in mediation of these effects after direct cell-cell contact of TAIC and melanoma cells selective inhibitors for Eph are applied in ongoing studies.
Keywords: Cell and Tumour Biology

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 120-121

Registration 14.07.2010 15:20, No. 14269

Imaging of neurotensin receptors in tumors by a novel stabilized ⁶⁴Cu-DOTA-neurotensin analog
Bergmann, R.; Brans, L.; Tourwe, D.; Schlottig, K.; Pietzsch, J.
Abstract: Background:
Neurotensin (NT) and its receptors (NTR) are overexpressed in various tumors (breast, prostate, lung, ductal pancreas, pituitary) and play a crucial role in tumor progression and malignancy. For tumor diagnosis and optimized targeted, individualized therapy it is important to image and quantify functional expression of these receptors. The development and radiopharmacological characterization of a novel stable neurotensin analog radiolabeled with ⁶⁴Cu is described.

Material and methods:
The peptide (ArgΨ(CH₂NH)ArgProdmTyrtLeuLeu-OH) was synthesized by manual solid phase synthesis on a Merrifield-resin and conjugated with DOTA (1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid). Radiolabeling of the peptide (3 nmol) with ⁶⁴CuCl₂ was carried out in 0.1 M ammonium acetate at pH 5.5, 37°C and 15 min. The IC₅₀ was determined on HT-29 cell membranes. Cell uptake and internalization was studied in HT-29 and PC3 cells. The biodistribution of the radiotracer was investigated in HT-29 tumor bearing NMRI nu/nu mice (5 min, 60 min p.i.; 4 animals per time point) and imaged by small animal PET (8 animals). The metabolic stability was analyzed in Wistar rats.

Results:
The binding affinity of the radiotracer towards NTR1 was 7 nM (4-12 nM, 95% confidence interval). The radiochemical purity after one step radiolabeling was greater than 92%. After single intravenous administration the activity concentration increased fast in the tumor (0.8±0.1 SUV, 5 min p.i.) and decreased to 0.3±0.1 SUV (60 min). At 60 min p.i. the tumor to organ ratios were 2.8±0.7 (blood), 5.2±0.9 (muscle), 4.2±0.6 (pancreas), 0.6±0.5 (liver), and 0.4±0.4 (kidneys). The radiotracer was fast accumulated in the kidneys (3.7±0.6 SUV, 5 min p.i.; 0.8±0.1 SUV, 60 min p.i.) and eliminated in the urine (60±6% injected dose, 60 min p.i.). The tumors were clearly delineated in the PET images. The tumor uptake of the radiotracer was competitively inhibited by 73% by simultaneous injection of the neurotensin derivative 8-13. In rat plasma 33% of the radioactivity accounted for the original compound at 60 min p.i.

Conclusions:
The novel ⁶⁴Cu-neurotensin analog with good stability and high receptor affinity allows for the in vivo imaging and functional characterization of NTR1 receptor overexpressing tumors. These findings are a prerequisite for other imaging applications, e.g., using SPECT radionuclides (¹¹¹In), and potentially also for targeted radionuclide therapy (⁶⁷Cu, ⁹⁰Y or ¹⁷⁷Lu).
Acknowledgement: This project was supported in part by the EC (Grant agreement no. 223057, GIPIO).

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 61(2010), 68-69

Registration 09.07.2010 08:44, No. 14258

Fluorine-18 and iodine-124 labeled cyclin-dependent kinase 4 and 6 inhibitors as radiotracers for tumor imaging by positron emission tomography (PET)
Graf, F.; Bergmann, R.; Koehler, L.; Mosch, B.; Steinbach, J.; Wuest, F.; Pietzsch, J.
Abstract: Background
Cyclin-dependent kinases 4 and 6 (Cdk4/6) function as critical activators of cell cycle progression in human tumors. Pyrido[2,3 d]pyrimidine derivatives CKIA and CKIE are selective Cdk4/6 inhibitors with high potency for the inhibition of G1 phase progression and tumor cell proliferation. The aim of this study was the evaluation of radiolabeled compounds [¹²⁴I]CKIA and [¹⁸F]CKIE as radiotracers for PET imaging of Cdk4/6 in tumors in vivo.

Materials and methods
Cellular uptake of radiotracers [¹²⁴I]CKIA and [¹⁸F]CKIE was studied in human colorectal (HT-29) and squamous cell (FaDu) carcinoma cells. Small animal PET studies of both radiotracers were performed in FaDu xenograft-bearing nude mice.

Results
Radiotracer uptake studies showed fast and high uptake (up to 800%ID/mg protein) of [¹²⁴I]CKIA in both cell lines after 1 h at 37°C. Cellular uptake of [¹⁸F]CKIE was lower (HT 29, 46.3±11.2%ID/mg protein; FaDu, 46.2±13.8%ID/mg protein). Radiotracer uptake was significantly lower at 4°C for [¹²⁴I]CKIA (150%ID/mg protein) and [¹⁸F]CKIE (15%ID/mg protein) after 1 h in both cell lines. Cellular uptake of [¹⁸F]CKIE was reduced to 18.0±4.9%ID/mg protein in the presence of 10 µM of nonradioactive CKIE at 37°C. Dynamic small animal PET studies showed rapid clearance of [¹²⁴I]CKIA and [¹⁸F]CKIE from the blood and fast hepatobiliary excretion. The half-life of radiotracer elimination from the blood was calculated to be 7.2 min for [¹²⁴I]CKIA and 7.9 min for [¹⁸F]CKIE, respectively. Radiotracers were rapidly metabolized in blood in vivo, yielding >90% (1 min p.i.), 20% (30 min), and <5% (1 h) of the original compounds. Small animal PET studies with [¹²⁴I]CKIA only showed marginal uptake of the radiotracer in the FaDu tumor. In the case of [¹⁸F]CKIE a higher uptake was detected in the peripheral proliferative region of the tumor after 1 h p.i. However, the constant tumor-to-muscle ratio of 1.5 suggests a non-Cdk4/6-mediated uptake of [¹⁸F]CKIE in human tumor xenografts in mice.

Conclusions
Synthesis of pyrido[2,3-d]pyrimidine-based radiotracers [¹²⁴I]CKIA and [¹⁸F]CKIE allowed for the first time the quantification of cellular uptake in vitro and imaging of tissue-specific distribution of Cdk4/6 inhibitors in vivo. However, the short biological half-life in the blood and low tumor uptake of [¹²⁴I]CKIA and [¹⁸F]CKIE limit the use of both radiotracers for the characterization of Cdk4/6 expression in tumors by means of PET. Further development of suitable radiolabeled Cdk4/6 inhibitors for functional characterization of Cdk4/6 in tumors continues to be of great interest in current translational cancer research.

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 61

Registration 09.07.2010 08:32, No. 14257

Effects of irradiation on viability, growth, metastatic properties and expression of Eph receptors and their ephrin ligands in human melanoma cells
Mosch, B.; Pietzsch, J.
Abstract: Background:
It is accepted that X-ray irradiation influences growth, viability and metastatic potential of tumor cells. Furthermore, it is supposed that tumor cell invasion and metastasis is regulated by Eph receptors and their ephrin ligands. The aim of our study was to investigate the influence of irradiation on cell viability, growth, and metastasis in human melanoma cells and whether this is mediated by dysregulated Eph receptor or ephrin ligand expression.

Material and Methods:
Primary (Mel-Juso) and metastatic (A375, A2058) human melanoma cell lines were irradiated with 5 or 10 Gy. Up to 7 days after irradiation we examined cell viability (MTT test). At 1 day and 7 days post irradiation we further analyzed cellular growth, motility (scratch assay), adhesion to fibronectin, and migration through a porous membrane. Furthermore, the mRNA expression of 8 different Eph receptors and 6 ephrin ligands was analyzed using RT-PCR.

Results:
In all cell lines a dose dependent decrease in viability and cell growth for up to 1 week after irradiation was demonstrated. Analysis of metastatic properties 1 day after X-ray showed decelerated scratch closure, slight increase in migration, and increased adhesion to fibronectin in all investigated cell lines. In contrast, 1 week after irradiation we detected faster scratch closure in irradiated primary Mel-Juso cells but unaltered motility in metastatic cell lines and, moreover, decreased migration in primary Mel-Juso cells and, by trend also in metastatic A375 cells. In addition, in Mel-Juso and A375 cells capability to adhere to fibronectin remained elevated. RT-PCR analysis revealed that Eph receptors and ephrins investigated have similar mRNA expression levels in primary and metastatic cell lines, with exception of both EphA2 and ephrinA5 showing enhanced expression in metastatic A375 cells. After irradiation changes in mRNA expression were not
detected with exception of an increase in EphA2 and EphA3 in A375 cells and ephrins A1 and A5 in A375 and Mel-Juso cells 7 days after treatment.

Conclusion:
Irradiation considerably influences viability and metastatic properties of melanoma cells. The different effects depending on time after irradiation observed suggest an involvement of cell-cell interaction via A-type Eph receptors and ephrins in irradiation-induced metastatic potency of melanoma cells.

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 211

Registration 08.07.2010 15:30, No. 14256

Concomitant targeting of cyclooxygenase-2 and oxidant stress pathways for radioprotection of normal vascular tissue
Pietzsch, J.; Pietzsch, F.-J.; Laube, M.; Bergmann, R.; Kniess, T.; Wuest, F.
Abstract: Background:
Radiotherapy of various cancers is closely associated with increased cardiovascular morbidity and mortality. Arachidonic acid metabolites are supposed to play a key role in radiation-induced vascular dysfunction, inflammation, and injury. This study was designed to evaluate the effects of novel selective cyclooxygenase-2 (COX-2) inhibitors on radiation-induced formation of arachidonic acid metabolites via cyclooxygenase-2 and oxidant stress pathways in endothelial cells.

Materials and methods:
Acute effects (1 d, 3 d) of X-ray radiation at moderate doses (2 to 10 Gy) without or with presence of selective COX-2 inhibitors (cyclopentene/indole/indomethacin derivatives (2 each); 1 µM, 10 µM) in human arterial (HAEC) and microvascular (HDMEC) endothelial cells compared to sham-irradiated controls were assessed. Therefore, the following parameters were measured: COX-2 induction; secretion of cytokines tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1; release of prostaglandins PGE2 and PGI2; release of isoprostanes 8-iso-PGE2 and 8-iso-PGF2α; and oxidative stress (lipid peroxides).

Results:
Irradiation of endothelial cells without presence of COX-2 inhibitors resulted in a dose-dependent augmentation of all parameters studied. When endothelial cells were exposed to COX-2 inhibitors during and for 24 h post irradiation, indole derivatives showed highest potency to inhibit release of both prostaglandins and isoprostanes. Furthermore, when irradiated cells were treated with indole derivatives a significant decrease of lipid peroxide formation and cytokine secretion could be observed, which indicates a direct interaction with oxidant stress-pathways. By contrast, both cyclopentene and indomethacin derivatives majorily inhibited prostaglandin release, but showed only slight effects on formation of isoprostanes, lipid peroxides and cytokines. Model experiments using human low density lipoproteins oxidized by radiolytically generated oxygen radicals showed that indole derivatives differently interact with peroxidation of polyunsaturated fatty acids, than the cyclopentene/indomethacin derivatives, suggesting a physico-chemical rationale for observed anti-oxidant activity.

Conclusion:
Indole-based selective COX-2 inhibitors substantially decreased radiation-induced formation of vasoactive isoprostanes
8-iso-PGE2 and 8-iso-PGF2α by endothelial cells. These findings may have particular importance in radiation-induced processes in which COX-2 is induced and oxidant stress occurs. The reduction of radiation-induced vascular dysfunction by antioxidative COX-2 inhibitors may widen the therapeutic window of cyclooxygenase-2 targeted treatment.

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 211

Registration 08.07.2010 15:21, No. 14255

Autocrine regulation of receptor for advanced glycation endproducts (RAGE) by S100A4 promotes migration and invasion in A375 melanoma cells
Wolf, S.; Haase-Kohn, C.; Lenk, J.; Pietzsch, J.
Abstract: Background
The calcium-binding protein S100A4 is associated with metastasis of different cancer entities, including melanoma. The multiligand receptor for advanced glycation endproducts (RAGE) has been suggested to interact with extracellular S100A4 protein. We hypothesized that the interaction between RAGE and S100A4 plays an important role in activation of growth, adhesion, motility and migration in a human melanoma cell line with high metastatic potential.

Materials and methods
In order to investigate the cellular role of the RAGE-S100A4 interaction in vitro, we produced recombinant S100A4 and soluble RAGE (sRAGE). Furthermore, we established A375 melanoma cells stably transfected with S100A4 using vector pIRES2-AcGFP1 (A375-S100A4). The overexpression of S100A4 has been verified by western blot and flow cytometry. Assays for determination of migratory, invasive and adhesive behaviour of A375-S100A4 cells were performed. Furthermore, specific interaction of S100A4 with RAGE was characterized by surface plasmon resonance spectroscopy using immobilized sRAGE.

Results
The overexpression of S100A4 did not influence growth properties and adhesive behaviour of the A375-S100A4 cells; however, it affects their motility and migratory activity in comparison to mock-transfected cells. A375-S100A4 cells show an increased secretion of S100A4 into the extracellular space and, in consequence, an enhanced RAGE protein expression. Molecular interaction studies revealed high affinity (lower micromolar range) of S100A4 towards immobilized sRAGE, suggesting a biochemical rationale for the observed effects.

Conclusion
This investigation shows that overexpression of S100A4 influences the metastatic behavior of A375 melanoma cells. The enhanced secretion of S100A4 leads to an autocrine upregulation of RAGE expression and synthesis in A375-S100A4 cells. The findings support the supposed functional role of RAGE-S100A4 interaction in promoting a metastatic phenotype of human melanoma.

Poster:
21st Meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 118-119

Registration 08.07.2010 15:08, No. 14254

Influence of irradiation on para- and autocrine regulation of extracellular S100A4 (metastasin) and its receptor RAGE in B16 mouse melanoma cells
Haase-Kohn, C.; Wolf, S.; Pietzsch, J.
Abstract: Background:
Malignant melanoma is one of the most invasive and metastatic tumors. A common therapeutic approach towards metastases will combine radiation with chemotherapy and/or surgery. The interaction between tumor and inflammatory cells, e.g., via S100A4 (metastasin) and the receptor for advanced glycation endproducts (RAGE), is hypothesized to play a key role in metastasis of melanoma. In this study the contribution of para- and autocrine S100A4-RAGE activation to growth, motility and migration of metastatic melanoma and inflammatory cells before and post irradiation was investigated.

Materials and methods:
Mouse melanoma cells (B16), macrophages (RAW; a model for tumor associated macrophages (TAM)) and B16/RAW cocultures (ratio 1 to 5) were exposed to single dose irradiation (5, 10, and 20 Gy, compared to sham-irradiated controls) for 0, 3 and 6 days. S100A4 and RAGE expression in these cells was quantified via real-time RT-PCR, Western-blot analysis and immunochemistry. Cell growth and cellular viability was detected by MTT assay. Migration assays of non- and irradiated cells were performed with and without chemoattractants (supernatants of irradiated cocultures after 6 days). Additionally, the actin cross-linker L-plastin was investigated as a migratory marker.

Results:
Post irradiation, S100A4 and RAGE mRNA expression was significantly increased in B16 and RAW cells but not in cocultivated cells. S100A4 protein expression was only detected in irradiated B16 cells whereas RAW cells always showed high levels in non- and irradiated cells. Interestingly, cocultures showed only minor S100A4 expression levels with a further reduction of S100A4 after irradiation. In contrast, RAGE protein showed only slight differences. A significant reduction of cell viability was observed after irradiation via MTT assay. On the other hand, migratory activity was significantly increased in B16 and cocultures after irradiation whereas RAW cells showed a significant decrease. Furthermore, chemoattractants significantly induced the migration in non-irradiated B16 cells.

Conclusion:
Irradiation of both melanoma cells and macrophages alters their migratory and invasive activity. Under conditions of cocultivation these effects were more pronounced. We suppose an involvement of para- and autocrine regulation of extracellular S100A4 and its receptor RAGE in melanoma cells and TAM, thereby changing functional properties of melanoma cells towards a promigratory phenotype.

Poster:
21st meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 211-212

Registration 08.07.2010 11:40, No. 14251

The impact of hypoxia on differential expression of neurotensin receptors (NTR) in colorectal and prostate carcinoma cells
Schlottig, K.; Bergmann, R.; Steinbach, J.; Haase-Kohn, C.; Pietzsch, J.
Abstract: Background:
Recent studies showed increased expression of neurotensin receptors (NTR), particularly, NTR1 and NTR3, in various tumors, thus NTR is assumed a potential target for tumor imaging and therapy. However, the knowledge about the quantitative expression of NTR on mRNA and protein level, e.g., under hypoxic conditions is limited. The aim of this study was to develop a quantitative method for determination of absolute NTR mRNA amount in tumor and non-tumor cells and tissues. For method evaluation the NTR mRNA amounts in human colorectal (HT-29) and prostate (PC3) carcinoma cell lines under normoxic and hypoxic conditions in vitro were compared.

Material and methods:
A novel real-time RT-PCR method using an external standard was established. The elongation factor 1 alpha (EF1α) gene served as housekeeping gene and glucose transporter protein type 1 gene (GLUT1) was used as indicator for cellular hypoxic regulation effects. The derived standard curves allow for calculation of the number of specific mRNA molecules normalized to 1000 molecules of EF1α. Acute and chronic experimental hypoxia was induced by cultivation of cells at an oxygen concentration of 0.6% for 4 to 72 hours.

Results:
Both HT-29 cells and PC3 cells show high mRNA expression of NTR1 in normoxia. In acute hypoxia (
Conclusion:
A novel standardizable and reproducible quantitative method for measurement of NTR mRNA in cancer cells was established. The use of NTR1 as a target for imaging or therapy strongly depends on tumor cell type and tumor hypoxia. Ongoing investigations will compare quantitative mRNA expression with data on functional expression of NTR, e.g., protein synthesis and radioligand interaction, in human samples and rodent tumor (xenograft) models.

Poster:
21st meeting of the European Association for Cancer Research (EACR-21), 26.-29.06.2010, Oslo, Norway
Conference abstract in ref. journal:
European Journal of Cancer 8(2010), 61

Registration 08.07.2010 11:24, No. 14250

Synthesis of neurotensin(8-13)-phosphopeptide heterodimers via click chemistry
Richter, S.; Ramenda, T.; Bergmann, R.; Knieß, T.; Steinbach, J.; Pietzsch, J.; Wuest, F.
Abstract: Two neurotensin(8-13)-containing peptide heterodimers were prepared via copper(I)-mediated click chemistry. The resulting peptide dimers could be obtained in 28-31% yield after HPLC purification. Neurotensin( 8-13)-containing peptide dimers were used in an in vitro binding assay to determine binding affinity towards the neurotensin receptor-1 (NTR1). The determined IC₅₀ values of 8.3 µM and 0.7 µM indicate only very low binding affinity of the neurotensin(8-13)-containing peptide heterodimers towards the NTR1.
Keywords: Click chemistry, Neurotensin receptor, Phosphopeptide, Peptide heterodimer

Bioorganic & Medicinal Chemistry Letters 20(2010), 3306-3309

Registration 23.06.2010 14:39, No. 14198


Encapsulation of Fluorescent Cluster Complexes into Dendritic Nanocontainer Kuhlmann, M. Abstract: kein Abstract verfügbar Lecture (Conference): 7th Supraphone Meeting, 28.04.-01.05.2010, Maria Laach, D Registration 23.06.2010 11:36, No. 14195


Personen- und Produktschutz bei der Herstellung von PET Radiopharmaka Füchtner, F. Abstract: kein Abstract verfügbar Invited lecture (Conferences): 2. NZW Dresden - Onkologisch-Pharmazeutischer Fachkongress, 18.-19.06.2010, Dresden, D Registration 23.06.2010 11:14, No. 14194

Effects of lateral fluid percussion injury on cholinergic markers in the newborn piglet brain
Donat, C. K.; Walter, B.; Kayser, T.; Deuther-Conrad, W.; Schliebs, R.; Nieber, K.; Bauer, R.; Haertig, W.; Brust, P.
Abstract: Traumatic brain injury is a leading cause of death and disability in children. Studies using adult animal models showed alterations of the central cholinergic neurotransmission as a result of trauma. However, there is a lack of knowledge about consequences of brain trauma on cholinergic function in the immature brain. It is hypothesized that trauma affects the relative acetylcholine esterase activity and causes a loss of cholinergic neurons in the immature brain. Severe fluid percussion trauma (FP-TBI, 3.8 0.3 atm) was induced in 15 female newborn piglets, monitored for 6 h and compared with 12 control animals. The hemispheres ipsilateral to FP-TBI obtained from seven piglets were used for acetylcholine esterase istochemistry on frozen sagittal slices, while regional cerebral blood flow and oxygen availability was determined in the remaining eight FP-TBI animals. Post-fixed slices were immunohistochemically labelled for choline acetyltransferase as well as for lowaffinity neurotrophin receptor in order to characterize cholinergic neurons in the basal forebrain. Regional cerebral blood flow and brain oxygen availability were reduced during the first 2 h after FPTBI (P < 0.05). In addition, acetylcholine esterase activity was significantly increased in the neocortex, basal forebrain, hypothalamus and medulla after trauma (P < 0.05), whereas the number of choline acetyltransferase and low-affinity neurotrophin receptor positive cells in the basal forebrain were unaffected by the injury. Thus, traumatic brain injury evoked an increased relative activity of the acetylcholine esterase in the immature brain early after injury, without loss of cholinergic neurons in the basal forebrain. These changes may contribute to developmental impairments after immature traumatic brain injury.
Keywords: Traumatic brain injury Immature brain Cholinergic system Acetylcholine esterase

International Journal of Developmental Neuroscience 28(2010), 31-38

Registration 17.06.2010 15:45, No. 14190

Alterations of cholinergic receptors and the vesicular acetylcholine transporter after lateral fluid percussion injury in newborn piglets
Donat, C. K.; Walter, B.; Deuther-Conrad, W.; Nieber, K.; Brust, R. Bauer P.
Abstract: Aims: Traumatic brain injury (TBI) is one of the leading causes of death and disability in children. Adult animal models of TBI showed cholinergic alterations. However, there is no comparable data on immature animals. Therefore, this study investigates cholinergic markers in a large animal model of juvenile TBI. Methods: Twenty-seven female newborn piglets were subjected to lateral fluid percussion (FP) injury and compared with 12 untreated animals. After 6 h, animals were sacrificed and the brains removed.The hemispheres ipsilateral to FP-TBI from seven piglets and corresponding hemispheres from six control animals were used for autoradiography. Receptor density was determined with [3H]epibatidine (nicotinic acetylcholine receptors) or [3H]QNB (muscarinic acetylcholine receptors). The density of the vesicular acetylcholine transporter (vAChT) was assessed with (-)-[3H]vesamicol. Cerebral blood flow was measured by coloured microsphere method. Results: Cerebral blood flow and brain oxygen delivery were transiently reduced early after FP-TBI (P < 0.05). TBI caused reductions of muscarinic acetylcholine receptor density (fmol/mg) in the basal forebrain (sham: 10797 1339, TBI: 8791 1031), while nicotinic acetylcholine receptor remained stable. Significant increases in vAChT density (fmol/mg) were observed in the basal forebrain (sham: 2347 171, TBI: 2884 544), putamen (sham: 2276 181, TBI: 2961 386), cortex (sham: 1928 262, TBI: 2377 294), thalamic areas (sham: 2133 272, TBI: 2659 413), hippocampus (sham: 2712 145, TBI: 3391 501) and hypothalamus (sham: 2659 139, TBI: 3084 304). Conclusions: Cholinergic markers are altered after mildto- moderate TBI in the immature brain.Whereas the ACh receptors are stable in almost any brain region after TBI, vAChT expression increases after trauma at the employed severity of this specific trauma model.
Keywords: muscarinic, newborn pig, nicotinic, receptor, traumatic brain injury, vesicular transporter

Neuropathology and Applied Neurobiology 36(2010), 225-236

Registration 17.06.2010 15:25, No. 14189

Novel Indole Derivatives as Potential Imaging Agents for Alzheimer’s Disease
Yu, L.; Scheunemann, M.; Deuther-Conrad, W.; Hiller, A.; Fischer, S.; Sorger, D.; Sabri, O.; Jia, H.; Steinbach, J.; Brust, P.; Liu, B.
Abstract: kein Abstract verfügbar
Keywords: β-Amyloid, Indole, Positron emission tomography, Senile plaques

Bulletin of the Korean Chemical Society 31(2010)1, 177-180

Registration 17.06.2010 14:43, No. 14187


Identifizierung von ¹¹C-Radiotracern mittels ¹³C-NMR Mamat, C. Abstract: kein Abstract verfügbar Lecture (others): Dresdner NMR-Seminar, 30.03.2010, Dresden, D Registration 10.06.2010 14:16, No. 14173

Crystal structure of N-benzyl-4-fluorobenzamide, C₁₄H₁₂FNO, at 173 K
Mamat, C.; Flemming, A.; Köckerling, M.
Abstract: C₁₄H₁₂FNO, monoclinic, P2₁/n (no. 14), a = 5.6653(2) Å,
b = 25.305(1) Å, c = 8.2832(3) Å, ß = 92.237(3)°,
V = 1186.6 Å³, Z = 4, R_gt(F) = 0.047, wR_ref(F²) = 0.123,
T = 173 K.

Zeitschrift für Kristallographie 225(2010), 345-346

Registration 10.06.2010 12:51, No. 14172

Recent Application of Click Chemistry for the Synthesis of Radiotracers for Molecular Imaging
Mamat, C.; Ramenda, T.; Wuest, F.
Abstract: Click chemistry has received considerable attention as powerful modular synthesis approach, which has found numerous applications in many areas of modern organic chemistry, drug discovery and material science. Recently, click chemistry, and in particular the copper-mediated 1,3-dipolar [3+2] cycloaddition between azides and alkynes, has also entered the field of radiopharmaceutical sciences. This review addresses the recent developments of click chemistry for the synthesis of various radiotracers for molecular imaging purposes. Click chemistry-based radiotracers that will be covered include peptides and small organic molecules containing the short-lived positron emitters fluorine-18, and the gamma-emitters technetium-99m, indium-111, and iodine-125.
Keywords: Click chemistry, radiopharmaceutical science, radiotracer

Mini-Reviews in Organic Chemistry 6(2009), 21-34

Registration 10.06.2010 12:31, No. 14171


Bispidine Derivatives for Dual-Modality Imaging Fähnemann, S. Abstract: kein Abstract verfügbar Lecture (Conference): 7th Supraphone Meeting, 28.04.-01.05.2010, Maria Laach, Deutschland Registration 07.06.2010 08:15, No. 14153

Iodine-124: A Promising Positron Emitter for Organic PET Chemistry
Koehler, L.; Gagnon, K.; Mcquarrie, S.; Wuest, F.
Abstract: The use of radiopharmaceuticals for molecular imaging of biochemical and physiological processes in vivo has evolved into an important diagnostic tool in modern nuclear medicine and medical research. Positron emission tomography (PET) is currently the most sophisticated molecular imaging methodology, mainly due to the unrivalled high sensitivity which allows for the studying of biochemistry in vivo on the molecular level. The most frequently used radionuclides for PET have relatively short half-lives (e. g. C-11: 20.4 min; F-18: 109.8 min) which may limit both the synthesis procedures and the time frame of PET studies. Iodine-124 (I-124, t(1/2) = 4.2 d) is an alternative long-lived PET radionuclide attracting increasing interest for long term clinical and small animal PET studies. The present review gives a survey on the use of I-124 as promising PET radionuclide for molecular imaging. The first part describes the production of I-124. The second part covers basic radiochemistry with I-124 focused on the synthesis of I-124-labeled compounds for molecular imaging purposes. The review concludes with a summary and an outlook on the future prospective of using the long-lived positron emitter I-124 in the field of organic PET chemistry and molecular imaging.

Molecules 15(2010), 2686-2718

Registration 03.06.2010 10:43, No. 14148

Efficient preparation of ^99mTc(III) ‘4+1’ mixed-ligand complexes for peptide labeling with high specific activity
Künstler, J.-U.; Seidel, G.; Pietzsch, H.-J.
Abstract: An improved labeling procedure for peptides attached to organometallic ^99mTc(III) ‘4+1’ mixed-ligand complexes in which the radiometal is coordinated by a tripodal tetradentate chelator 2,2',2''-nitrilotriethanethiol (NS₃) and a monodentate isocyanide ligand is presented. The labeling procedure was evaluated by the synthesis of [^99mTc(NS₃)(L2-RGD)]. The containing radiopharmaceutically interesting RGD-peptide cyclo[Arg-Gly-Asp-D-Tyr-Lys] was modified with 4-isocyanobutanoic acid (L2) as linker conjugated to N⁶-Lys to get the monodentate ligand L2-RGD. The structural identity of the ^99mTc-conjugate was confirmed by comparison to a Re reference compound. The Tc- and Re-conjugates had matching retention times under identical HPLC conditions. The ^99mTc-labeling was performed in a novel one-step procedure using the eluate of a ⁹⁹Mo/^99mTc generator, NS₃, the isocyanide modified peptide, SnCl₂, Na₂EDTA, mannitol and ascorbic acid in the reaction mixture. Using optimized reagents it is possible to label 50 nmol peptide with ^99mTc within 60 min at room temperature with a radiochemical yield higher than 95% and a specific activity of ~20 GBq/mmol.
Keywords: Technetium-99m; ‘4+1’ mixed-ligand complexes; Peptide labeling; Specific activity

Applied Radiation and Isotopes 68(2010), 1728-1733

Registration 03.06.2010 10:20, No. 14147

Enantioseparation of vesamicol and novel vesamicol analogs by high-performance liquid chromatography on different chiral stationary phases
Wenzel, B.; Fischer, S.; Brust, P.; Steinbach, J.
Abstract: High-performance liquid chromatography enantioseparation of vesamicol and six novel azaspirovesamicols (amino alcohols) was accomplished on different chiral stationary phases (CSPs) by using an optical rotation based chiral detector for identification of the resolved enantiomers. The Pirkle-type column Reprosil Chiral-NR was found to be most suitable for chiral resolution in normal phase (NP) mode; all compounds could be enantioseparated successfully. Also the cellulose-based column Reprosil Chiral-OM showed appropriate separation properties by using NP conditions. The amylose-type column Reprosil Chiral-AM-RP was most suitable for enantioseparation in reversed phase (RP) mode; five out of seven compounds were resolved. This CSP showed a considerably higher capability for chiral recognition of vesamicol derivatives in RP mode than the corresponding cellulose-based column Reprosil Chiral-OM-RP. Enantioseparation with the teicoplanin aglycone-based column Reprosil Chiral-AA was successful under polar ionic mobile phase conditions.
Keywords: Vesamicol Azaspirovesamicol Chiral separation Chiral stationary phases Polysaccharide-type CSP Pirkle-type CSP Teicoplanin aglycone CSP Chiral detector

Journal of Chromatography A 1217(2010), 3855-3862

Registration 25.05.2010 10:27, No. 14116

Modified automated synthesis of sodium 2-[¹⁸F]fluoroacetate using a Tracerlab_FXN synthesizer.
Kniess, T.; Richter, S.; Steinbach, J.
Abstract: 1. Introduction:
Prostate cancer is the most frequently diagnosed cancer in men over the age of 40 years in Europe and the USA and its early detection is crucial for prognosis and outcome of the disease. Besides the established radiotracers based on ¹¹C- and ¹⁸F-labeled choline [¹¹C]acetate is used for the early detection of prostate cancer and its recurrence. 2-[¹⁸F]Fluoroacetate has been proposed as alternative to [¹¹C]acetate offering the advantage of longer half-life which facilitates synthesis, shipping and allowing longer imaging protocols. A few radiosyntheses of the radiotracer have been published in the past, mainly based on trapping of the 2-[¹⁸F]fluoroacetate ethylester on C18 cartridges (Oasis HLB), followed by acidic hydrolysis [1-3]. Our approach is the fully automated synthesis of 2-[¹⁸F]fluoroacetate with a Tracerlab_FXN synthesizer including separation of the radiotracer via anion exchange cartridges in alkaline solution.

2. Materials and methods:
The radiolabeling with [¹⁸F]fluoride was performed with 2-methanesulfonyl-acetic acid t-butyl-ester as precursor in acetonitrile at 100°C. After hydrolysis with 1M HCl and addition of 1M NaOH the alkaline reaction mixture was diluted with 20mL of water and passed through a combination of two anion exchange cartridges where 2-[¹⁸F]fluoroacetate was trapped. The 2-[¹⁸F]fluoroacetate was recovered by elution with NaHCO₃ and excess [¹⁸F]fluoride was removed by alumina N cartridges to provide radiochemical pure sodium 2-[¹⁸F]fluoroacetate (radio-TLC, RP18, acetonitrile/water=85/15; R_f=0.59).

3. Results:
The radiosynthesis of sodium 2-[¹⁸F]fluoroacetate was accomplished with a TracerlabFXN synthesizer by a fully automated procedure. The purification of the product was performed by anion exchange cartridges and gave the radiotracer in 27-30% yield (decay-corrected) and 99% radiochemical purity within 30 min total synthesis time.

4. Discussion/Conclusion:
The modified approach of radiosynthesis and purification delivers sodium 2-[¹⁸F]fluoroacetate in high radiochemical purity and good radiochemical yield. The improved radio-TLC method using RP18 plates represents an easy system to distinguish [¹⁸F]fluoride from 2-[¹⁸F]fluoroacetate. Further optimization of this new method utilising a new precursor and a modified separation system is in progress. The conformation of the process to GMP requirements will be performed in the near future.

References:
[1] Sun LQ, Mori T, Dence CS, Ponde DE, Welch MJ, Furukawa T, Yonekura Y, Fujibayashi Y, [2006], Nucl.Med.Biol., 33:153-158
[2] Ponde DE, Dence CS, Oyama N, Kim J, Tai YC, Laforest R, Siegel BA, Welch MJ, [2007], J.Nucl.Med., 48(3): 420-428
[3] Marik J, Ogasawara A, McNulty BM, Ross J, Flores JE, Gill HS, Tinianow JN, Vanderbilt AN, Nishimura M, Peale F, Pastuskovas C, Greve JM, van Bruggen N, Williams SP, [2009], J.Nucl.Med., 50(6): 982-990

Poster:
15th European Symposium on Radiopharmacy and Radiopharmaceuticals (ESRR), 08.-11.04.2010, Edinburgh, Großbritannien
Conference abstract in ref. journal:
Quarterly Journal of Nuclear Medicine and Molecular Imaging 54(2010)S1, 54

Registration 13.04.2010 15:55, No. 13996

Wie flexibel ist die Einwirkzeit von 18F-NaF
May, C.; Beuthien-Baumann, B.; Oehme, L.; Kotzerke, J.
Abstract: Ziel/Aim:
Bedingt durch die bestehende Knappheit an 99m-Technetium wurden vermehrte Skelettszintigraphien mit 18F-Natriumfluorid (18F-NaF) am PET-Scanner (Siemens HR+) durchgeführt. Es sollte untersucht werden, wie flexibel die Einwirkzeit des 18F-NaF in der Routine gehandhabt werden kann, ohne die Bildqualität negativ zu beeinflussen.

Methodik/Methods:
Der PET-Scan wurde in 3D-Listmode-Technik aufgenommen, 360 MBq 18F-NaF, Emissionsdauer von 4 min pro Bettposition, keine Schwächungskorrektur. Der Abstand von Injektion von 18F-NaF zum Untersuchungssbeginn betrug in der ersten Gruppe 40-60 min, in der 2. Gruppe 60-80 min, in der 3.Gruppe 80-120 min. Bislang wurden 10 Patienten pro Gruppe ausgewertet. Es wurden standardisierte Regions of interest über Lunge und LWK1 (bzw LWK 2 oder BWK 12 gelegt, falls bei LWK 1 eine pathologische Mehranreicherung erkennen ließ) und Quotienten aus Anreicherung in LWK und Lunge gebildet.

Ergebnisse/Results:
Qualitativ konnten alle Patienten ausgewertet werden. Der Mittelwert der Quotienten aus LWK/Lunge betrug für die Gruppe 40-60 min p.i. 2,4; für die Gruppe 60-80 min p.i. 2,3 und für die Gruppe 80-120 min p.i. 3,0. Zwischen Gruppe 1 und 2 bestand hinsichtlich der LWK/Lunge-Quotienten kein wesentlicher Unterschied. Der Mittelwert für die Gruppe 3 lag mit 3,0 etwas höher, unterschied sich jedoch statistisch nicht signifikant von Gruppe 1 und 2.

Schlussfolgerungen/Conclusions:
Nach 40 min ist ohne weiteres eine Aufnahme mit 18F-Fluorid mit guter Bildqualität möglich. Unsere Berechnungen haben ergeben, dass bei einer Einwirkzeit zwischen 40 -80 min keine wesentlichen Qualitätsunterschiede zu erwarten sind. Dadurch fügt sich die Skelettaufnahme am PET flexibel in den Tagesablauf ein. Einen möglichen Gewinn an Bildqualität nach 80-120 min sollte man sich bei adipösen Patienten zu nutze machen.

Poster:
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A113

Registration 12.04.2010 16:47, No. 13992

Wie weit bewegen sich die Schwerpunkte hypoxischer Tumorsubvolumina von HNO-Tumoren unter kombinierter Radiochemotherapie.
Abolmaali, N.; Zöphel, K.; Koch, A.; Haase, R.; Steinbach, J.; Baumann, M.
Abstract: Ziel/Aim:
Die Berücksichtigung hypoxischer Tumorsubvolumina anhand von FMISO-Daten zur Strahlentherapieplanung ist aufgrund des geringen Signal-zu-Rausch-Verhältnisses schwierig, weil die Konturen nicht eindeutig definiert sind. Ziel dieser Untersuchung war darzustellen, wie weit sich die Schwerpunkte Wie weit wandern die Schwerpunkte hypoxischer Tumorsubvolumina unter kombinierter Radiochemotherapie bewegen.

Methodik/Methods:
14 Patienten (2@, medianes Alter 55 Jahre) mit Plattenepithelkarzinomen des HNO-Traktes wurden vor kombinierter Radiochemotherapie (RCT) mit FDG sowie vor und nach 10Gy, 20Gy und 60Gy unter RCT mit FMISO untersucht (56 Untersuchungen). Mit der Rover-Software (ABX, Radeberg) wurde anhand der co-registrierten Daten Kontrast-basiert in jeder Untersuchung ein hypoxisches Tumorsubvolumen definiert und dessen Schwerpunkt im Koordinatensystem bestimmt. Die Bewegung dieses Schwerpunktes im Raum wurde unter RCT vermessen.

Ergebnisse/Results:
Im Mittel bewegen sich die Tumoren von der ersten zur zweiten Untersuchung um 5.6 mm, von der zweiten zur dritten Untersuchung um 5.5 mm und von der dritten zur vierten Untersuchung um 8 mm. Zwischen erster und vierter Untersuchung bewegten sich die Tumoren um 8.8 mm am weitesten. Die durchschnittliche Verschiebung des Schwerpunktes unter RCT lag bei 6.4 mm.

Schlussfolgerungen/Conclusions:
Unter Berücksichtigung der Registrierungsgenauigkeit von 2 mm und der maximalen Schwerpunktsbewegung von 9 mm erfasst der Strahlentherapieplan am Ende der Therapie das mit FMISO primär geplante Zielvolumen noch vollständig, wenn die üblichen Sicherheitsabstände berücksichtigt werden.

Poster:
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A80

Registration 12.04.2010 16:38, No. 13991

Für die Analyse hypoxischer Tumorvolumina sind 4h-FMISO-Aufnahmen besser geeignet als 2h-FMISO-Aufnahmen.
Abolmaali, N.; Zöphel, K.; Koch, A.; Zips, D.; Steinbach, J.; Baumann, M.
Abstract: Ziel/Aim:
Die F-18-Misonidazol-PET (FMISO) zur Detektion hypoxischer Tumorsubvolumina weist ein vergleichsweise geringes Signal-zu-Rausch-Verhältnis auf. Üblicherweise werden neben der Dynamik Aufnahmen nach 2h und 4h p.i. angefertigt. Ziel dieser Untersuchung war es zu entscheiden, welche der beiden Spätaufnahmen den besten Kontrast hat und damit am besten für Volumenanalysen geeignet ist.

Methodik/Methods:
25 Patienten (3@, medianes Alter 55 Jahre) mit Plattenepithelkarzinomen des HNO-Traktes wurden vor kombinierter Radiochemotherapie (RCT) mit FDG sowie vor und nach 10Gy, 20Gy und 60Gy unter RCT mit FMISO untersucht (66 Untersuchungen). Mit der Rover-Software (ABX, Radeberg) wurde nach Co-Registrierung der PETs mit dem halbautomatischen Source-to-Background-Algorithmus anhand der FDG-Daten das Tumorgesamtvolumen definiert und in die FMISO kopiert. In diesem Tumorvolumen wurde die MISO-Aktivität bestimmt. Zusätzlich wurde in jeder FMISO ein 5-10 ml großes Referenzvolumen zur Definition des Hintergrundsignals von MISO in der Halsmuskulatur als definiert. Der Kontrast wurde mit dem Verhältnis MISO-Aktivität im Tumor zu MISO-Aktivität im Hintergrund bestimmt. Der statistische Vergleich erfolgte mit dem Wilcoxon-matched-pairs Test.

Ergebnisse/Results:
Der mittlere SUVmax im Tumor nach 2h war 1.9, nach 4h 2.3, der mittlere SUVmean in der Halsmuskulatur nach 2h war 1.2 und nach 4h 1.1. Der Mittelwert±Standardabweichung für den Kontrast nach 2h war 1.33±0.28 und nach 4h 1.41±0.32. Mediane, Minima und Maxima für den Kontrast lagen nach 2h bei 1.29, 0.81 und 2.06 und nach 4h bei 1.38, 0.90 und 2.33. Der Wilcoxon-matched-pairs Test ergab einen hoch signifikanten Unterschied für die Kontraste zwischen diesen beiden Untersuchungszeitpunkten (p = 0.000052).

Schlussfolgerungen/Conclusions:
Für Volumenanalysen von FMISO, z.B. für die Strahlentherapieplanung sind 4h-Daten besser geeignet als 2h-Daten.

Poster:
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A80

Registration 12.04.2010 16:30, No. 13990

Verlaufsbeobachtung der Hypoxie anhand von FMISO-Untersuchungen in HNO-Tumoren unter kombinierter Radiochemotherapie.
Abolmaali, N.; Zöphel, K.; Koch, A.; Appold, S.; Steinbach, J.; Baumann, M.
Abstract: Ziel/Aim:
Zur Optimierung/Individualisierung der Strahlentherapie könnte die Detektion und Berücksichtigung hypoxischer Tumorsubvolumina im Therapieverlauf wichtig sein. Ziel dieser Untersuchung war darzustellen, wie sich in Tumoren die Hypoxie im Vergleich zum nicht im primären Zielvolumen gelegenen Normalgewebe verändert.

Methodik/Methods:
25 Patienten (3@, medianes Alter 55 Jahre) mit Plattenepithelkarzinomen des HNO-Traktes wurden vor kombinierter Radiochemotherapie (RCT) mit FDG sowie vor und nach 10Gy, 20Gy und 60Gy unter RCT mit FMISO untersucht (66 Untersuchungen). Mit der Rover-Software (ABX, Radeberg) wurde nach Co-Registrierung der PETs mit dem halbautomatischen Source-to-Background-Algorithmus anhand der FDG-Daten das Tumorgesamtvolumen definiert und in die FMISO kopiert. In diesem Tumorvolumen wurde die MISO-Aktivität bestimmt. Zusätzlich wurde in jeder FMISO ein 5-10 ml großes Referenzvolumen zur Definition des Hintergrundsignals von MISO in der Halsmuskulatur definiert. Bestimmt wurden im Verlauf der SUVmax, das hypoxische Volumen ("total lesion hypoxia (TLH)" = SUVmean x Volumen) und der Kontrast in Abhängigkeit von der MISO-Aktivität im Hintergrund.

Ergebnisse/Results:
Der gemittelte SUVmax±sd vor, nach 10Gy, nach 20Gy und nach 60Gy lag bei: 2.6±0.6, 2.6±0.7, 2.1±0.6 und 1.6±04. Der SUVmax sank im Mittel auf 64% des Ausgangswertes. Die TLH [ml] vor, nach 10Gy, nach 20Gy und nach 60Gy lag bei: 93.3 ml, 79.6 ml, 77.3 ml und 55.3 ml. Der Kontrast vor, nach 10Gy, nach 20Gy und nach 60Gy lag bei: 1.6±0.3, 1.6±3.9, 1.4±02 und 1.1±0.2. Der Kontrast sank im Mittel auf 71% des Ausgangswertes.

Schlussfolgerungen/Conclusions:
Unter kombinierter Radiochemotherapie sinkt sowohl das Tumorvolumen (erkennbar an den morphologischen CT-Daten) als auch die hypoxische Aktivität der HNO-Tumoren. Da nach 60 Gy der Kontrast in den FMISO-Untersuchungen nahe 1 liegt, lässt sich anhand der aufgenommenen Daten keine Planung für einen Strahlentherapieboost erstellen.

Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A30

Registration 12.04.2010 16:22, No. 13988

Vorklinische Abschätzung der Strahlenexposition durch (-)-F-18-NCFHEB, einem neuen PET-Tracer zur Darstellung von zerebralen alpha4beta2 nikotinischen Acetylcholinrezeptoren
Sattler, B.; Deuther-Conrad, W.; Fischer, S.; Hiller, A.; Kendziorra, K.; Starke, A.; Patt, M.; Hesse, S.; Smits, R.; Hoepping, A.; Steinbach, J.; Brust, P.; Sabri, O.
Abstract: Ziel/Aim:
(-)-F-18-Norchloro-fluoro-homoepibatidin (-)-NCFHEB) ist ein neuer vielversprechender Tracer für die Darstellung von alpha4beta2 nikotinischen Acetylcholinrezeptoren bei neuropsychiatrischen Erkrankungen mit PET. Um die Strahlenexposition durch die Applikation des Tracers abzuschätzen, wurde CD1 Mäusen (-)-NCFHEB appliziert. Es wurden die Biodistribution und die resultierenden Organdosen (OD) sowie die effektive Dosis (ED) bestimmt.

Methodik/Methods:
27 weiblichen CD1 Mäusen (Gewicht: 28,2 ± 2,1g) wurden 0,75± 0,334MBq (-)-F-18-NCFHEB [1] über die V. caudata lateralis appliziert. Nach 5, 15, 30, 45, 60, 90, 120, 180 und 240 min p.i. wurden die Tiere getötet (n=3 pro Zeitpunkt). Die Organe (Hirn, Herz, Lunge, Magen, Dünndarm, Dickdarm, Leber, Nieren, Harnblase, Milz, Thymus, Bauchspeicheldrüse, Nebennieren, Ovarien, Blut, Haut, Muskel, Skelett) wurden isoliert, gewogen und ihr Aktivitätsgehalt in einem g-Counter bestimmt. Die Massen von Skelett und Muskel wurden aus Gewebeproben extrapoliert [2]. Die Zeit- und Massenskalen wurden an die menschlichen Skalen angepasst [3]. Die Aktivitätsanteile in Quellorganen wurden als Fraktionen der injizierten Aktivitätsmenge [%ID] pro Gramm bzw. Organ dargestellt. Mit trapezoiden und exponentiellen Anpassungen an diese Daten wurden Zeit-Aktivitätskurven für jedes Organ bzw. Kompartiment abgeleitet. Die kumulierte Aktivität in den Quellorganen wurden bestimmt und ODs und die ED wurden mit OLINDA abgeschätzt.

Ergebnisse/Results:
Die Harnblase erhält die höchste OD mit 104,0 μSv/MBq, gefolgt von den Nieren (24,2 μSv/MBq), dem Uterus (14,1 μSv/MBq), der Leber (14,0 μSv/MBq) und der Bauchspeicheldrüse (14,0 μSv/MBq). Den höchsten Beitrag zur ED leistet die Harnblase (5,2μSv/MBq) gefolgt von den Ovarien (2,1μSv/MBq), dem Dickdarm (1,5μSv/MBq) und dem roten Knochenmark (1,3 μSv/MBq). Mit diesen Daten ergibt sich die ED durch i.v. Applikation von (-)-F-18-NCFHEB zu 14,2 μSv/MBq.

Schlussfolgerungen/Conclusions:
Die ED durch i.v. Applikation von etwa 370 MBq (-)-F-18-NCFHEB am Menschen ergibt sich zu 5,3 mSv. Dies liegt im Bereich der Strahlenexposition, welche durch andere F-18-markierte Radioliganden erzeugt wird. Diese vorklinischen inkorporationsdosimetrischen Ergebnisse bestärken die weitere Entwicklung von (-)-F-18-NCFHEB in klinischen Studienphasen am Menschen und seine weitere Entwicklung als klinischer Hirn-PET-Tracer.

Literatur/References:
[1] Brust P et. al.: In vivo measurement of nicotinic acetylcholine receptors with [18F]norchloro-fluoro-homoepibatidine (NCFHEB). Synapse 62, 205-218.
[2] Lindstedt SL, Schaeffer PJ.: Use of allometry in predicting anatomical and physiological parameters of mammals Laboratory Animals (2002) 36, 1–19
[3] Stabin MJ: Fundamentals of Nuclear Medicine Dosimetry, Springer 2008, ISBN 978-0-387-74578-7, 237P Diese Studie wird durch das Bundesministerium für Bildung und Forschung unterstützt. (Nr. 01EZ0820)

Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A66

Registration 12.04.2010 16:03, No. 13987

Erste in-vivo Applikation eines Fluor-18 markierten Serotonin-Transporter-(SERT)-Markers für die PET
Hesse, S.; Brust, P.; Mäding, P.; Bresch, A.; Zessin, J.; Becker, G. A.; Seese, A.; Habermann, B.; Patt, M.; Meyer, P. M.; Luthardt, J.; Steinbach, J.; Sabri, O.
Abstract: Ziel/Aim:
Die zentralen SERT lassen sich mittels SPECT-Radiotracern in SERT-reichen Gehirnarealen und mit PET-Markern wie [¹¹C]DASB hochselektiv im gesamten Gehirn darstellen. Die kortikale Test-Retest-Reliabilität von [¹¹C]DASB PET ist lediglich moderat, eine Quantifizierung endogenen Serotonins gelingt mit dieser Methode nicht. Möglicherweise können Tracer mit längerlebigen Nukliden diese Mängel beseitigen helfen. Ziel unserer Studie war die erstmalige Applikation eines Fluor-18-markierten SERT-Radiotracers im Menschen.

Methodik/Methods:
In Anlehnung an (1) wurde die Synthese von [¹⁸F]FMe-McN 5652 unter GMP-Bedingungen in einem modifizierten Synthesemodul "TRACERlab FxF-N” als 2-Stufen-2-Topf-Reaktion adaptiert: Stufe 1: Synthese von [¹⁸F]Fluormethylbromid durch nukleophile [¹⁸F]Fluorierung von Dibrommethan und nachfolgende Reinigung mittels Silicagel-Kartuschen (2). Stufe 2: [¹⁸F]Fluormethylierung eines entsprechenden Thiolat-Präkursors. Da [¹⁸F]FMe-McN 5652 in wässriger Lösung nicht stabil ist, wurde eine HPLC-Reinigung unter Verwendung eines ethanolischen Eluenten entwickelt, in deren Produktfraktion der Tracer stabil ist. Die PET-Datensätze, erhoben bei 5 gesunden Probanden (2 weiblich, Alter 39±10 Jahre) als dynamische Akquisition über 120 Min. nach i.v. 90-Sek.-Bolusinjektion von 298±57 MBq [¹⁸F]FMe-McN 5652 sowie statische Aufnahmen über 30 Min, wurden mit dem individuellen MRT koregistriert (PMOD) und mittels VOI analysiert (Target-/Background-Ratios, TB-R, Background=Zerebellum).

Ergebnisse/Results:
Die TB-R für den frontalen Kortex (FC) betragen 1,02±0,04 für rechts und 1,01±0,03 für links, für die Kaudatuskopfregion (Kaud) 1,46±0,16 (rechts) und 1,50±0,15 (links) und für die RaphÈ-Region 2,04±0,11. Vergleichsweise finden sich bei gesunden Probanden, die mittels [¹¹C]DASB-PET untersucht wurden (N=21, 11 weiblich, 38±8 Jahre), entsprechende TB-R von 1,10±0,07 (FC rechts, t-Test: n.s.), 1,08±0,78 (FC links, n.s.), 2,14±0,21 (Kaud rechts, n.s.), 2,06±0,19 (Kaud links, n.s.) und 2,23±0,39 (RaphÈ, n.s.) bei insgesamt visuell besserer Bildqualität des neuen Tracers.

Schlussfolgerungen/Conclusions:
Die zerebrale [¹⁸F]FMe-McN 5652-Aufnahme entspricht der Verteilung der SERT auch beim Menschen, so dass der Radiotracer einen geeigneten Marker für SERT darstellen könnte. Trotz der tendenziell geringeren TB-R im Vergleich mit den [¹¹C]DASB-PET-Daten könnte sich die geringere Standardabweichung bei der Untersuchung der Test-Retest-Reliabilität mit größeren Fallzahlen als Vorteil erweisen. Zudem soll mit Verdrängungsstudien die Sensivitität des neuen Markers, insbesondere in den kortikalen Arealen und hinsichtlich der Quantifizierung endogenen Serotonins, eingeschätzt werden.

Literatur/References:
(1) Zessin J, Eskola O, Brust P et al. Nucl Med Biol 2001; 28: 857-863.
(2) Iwata R, Pascali C, Bogni A et al. Appl Radiat Isot 2002; 57: 347-352

Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A34
Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D

Registration 12.04.2010 14:55, No. 13985

Ein neues stabilisiertes Cu-64 markiertes Neurotensin-Analogon zur in vivo Bildgebung von Neurotensin-Rezeptoren
Bergmann, R.; Brans, L.; Tourwe, D.; Schlottig, K.; Pietzsch, J.
Abstract: Ziel/Aim:
Neurotensin (NT) und seine Rezeptoren werden in verschiedenen humanen Tumoren (Brust-, Prostata-, Lungen-, duktale Pankreas- und Hypophysentumore) überexprimiert, insbesondere stehen sie im Zusammenhang mit der Tumorprogression und dem Übergang zu aggressiveren Tumorphänotypen. Deshalb kommt der quantitativen in vivo-Bildgebung der funktionellen Neurotensin-Rezeptor-Expression, sowohl in der Forschung, als auch in Diagnostik und Therapie besondere Bedeutung zu. Deshalb sollte ein in vivo stabiles Neurotensin-Analogon entwickelt werden, das sowohl zur Bildgebung, als auch für therapeutische Zwecke eingesetzt werden kann.

Methodik/Methods:
Durch manuelle Festphasensynthese auf Merrifield-Resin mit anschließender DOTA-Konjugation wurde DOTA-ArgΨ(CH2NH)ArgProDmtTleLeu-OH synthetisiert. Die Markierung des Peptides (3 pmol) mit Cu-64 erfolgte in Ammoniumacetat-Lösung 0,1 M, pH 5.5 über 15 min bei 50&inf;C. Der IC50 wurde an HT-29-Zellen bestimmt. Zellaufnahme und Internalisierung wurden an HT-29- und PC3-Zellen untersucht. Die Bioverteilung des Radiotracers wurde bei HT-29- tumortragenden NMRI-Nacktmäusen sowohl durch Organentnahme (je 4 Tiere pro Zeitpunkt), als auch mit Kleintier-PET (insgesamt 8 Tiere) untersucht. Die Dynamik der Metabolisierung wurde bei Ratten bestimmt.

Ergebnisse/Results:
Die Bindungsaffinität des Peptides an HT-29-Membranen, mit Neurotensin-Rezeptor 1 betrug 7 nM (4-12 nM, 95% Konfidenzintervall). Das Peptid konnte mit einer radiochemischen Reinheit größer 92% in einem Schritt mit Cu-64 markiert werden. Nach einmaliger intravenöser Injektion stieg die Konzentration im Tumor schnell an (0,8±0,1 SUV, 5 min p.i.) und verringerte sich dann auf 0,3±0,1 SUV (60 min p.i.). Daraus ergaben sich Tumor zu Organ-Verhältnisse von 2,8±0,7 im Blut, 5,2±0,9 im Muskel, 4,2±0,6 im Pankreas, 0,6±0,5 in Leber und 0,4±0,4 in Nieren. Das Peptid wurde schnell von den Nieren (3,7±0,6 SUV, 5 min p.i.; 0,8±0,1 SUV 60 min p.i. ) aufgenommen und in den Urin (60±6%ID im Urin nach 1 h) eliminiert . In der PET konnten die xenotransplantierten Tumore deutlich dargestellt werden. Bei gleichzeitiger Injektion von Neurotensin verringerte sich die Tumoraufnahme des Tracers auf 27% der Kontrolle. Nach 1 h lagen noch 33% der Aktivität im Blutplasma der Ratte als Originalsubstanz vor.

Schlussfolgerungen/Conclusions:
Das Cu-64-Neurotensin-Analogon erlaubt auf Grund seiner Stabilität, Affinität und Spezifität die bildgebende Darstellung der funktionellen Expression von Neurotensin-Rezeptoren in vivo. Die Daten lassen erwarten, dass ähnliche Ergebnisse auch mit Radionukliden für SPECT (In-111) oder therapeutische Anwendungen (Cu-67, Lu-177, Y-90) erreicht werden können.

Literatur/References:
Das Projekt wurde partiell durch das EU-Projekt GIPIO (Grant Agreement Nr. 223057) gefördert.

Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A17

Registration 12.04.2010 14:23, No. 13983

Markierung und Stabilität von DOTA Mikrosphären markiert mit Ga-68, Y-90 und Lu-177
Wunderlich, G.; Schiller, E.; Bergmann, R.; Pietzsch, H.-J.; Kotzerke, J.
Abstract: Ziel/Aim:
Intraarteriell applizierbare Partikel, markiert mit therapeutisch wirksamen Radionukliden (Y-90, Lu-177, Re-188) sind eine Alternative zur Behandlung von Lebertumoren und Lebermetastasen. Ga-68 markierte Partikel könnten zur Blutflussdarstellung und zur Lungenperfusion verwendet werden. In unserer Untersuchung verwendeten wir 20μm HSA Mikrosphären (MS). Es wurde untersucht, unter welchen Bedingungen sich DOTA modifizierte MS markieren lassen und wie stabil die Markierungen in vitro und in vivo sind.

Methodik/Methods:
Markiert wurde 1mg MS in 0,5M Azetatpuffer bei pH5, Reaktion 15min bei 95&inf;C unter Schütteln mit 0,1-0,5GBq Ga-68, 0,1-7,2GBq Y-90 und 1,8GBq Lu-177. Die Ausbeuten und die in vitro Stabilität wurden mit ITLC und nach Zentrifugieren bestimmt. Nach Zugabe von 1ml 0,1M DTPA Lösung (Challenge), 20mg Ascorbinsäure (Radikalfänger) und Stehenlassen der Suspension bestimmten wir die in vitro Stabilität der Produkte nach einigen Stunden bis Tagen in Gegenwart von DTPA/Ascorbinsäure bzw. Plasma und die in vivo Stabilität der Y-90 DOTA-MS nach intravenöser Injektion in Wistar-Ratten.

Ergebnisse/Results:
Die Markierungsausbeuten betrugen bei allen Nukliden >90%. Zur Bestimmung der in vitro Stabilitäten wurde das Produkt zentrifugiert und der Überstand abgenommen und/oder nach Aufschütteln eine Dünnschichtchromatografie durchgeführt. Nach 3h Inkubation in Humanplasma wurde 5% Ga-68 im Überstand gefunden. Nach Ascorbinsäurezugabe zum Reaktionsansatz fanden sich 18% freies Lu-177 nach 7d. Bei Y-90 DOTA MS wurden in Gegenwart von Ascorbinsäure bei Markierungen im GBq-Bereich im Überstand der Partikelsuspension unmittelbar nach Markierung bereits >10% der Radioaktivität nachgewiesen. Dabei handelt es sich wahrscheinlich um Y-90 DOTA-Thioharnstoffderivate, die vermutlich in Folge von Radiolyse und erhöhter Temperatur von den Partikeln abgespalten werden. Die Halbwertszeit von Y-90 DOTA-MS in der Lunge nach i.v. Injektion der Partikel in Wistarratten beträgt 3,5d.

Schlussfolgerungen/Conclusions:
Die Stabilität der Ga-68 markierten MS ist ausreichend für in vivo Anwendungen. Y-90 markierte Albumin-MS sind radiolytisch instabil und werden in vivo relativ rasch abgebaut. Sie sind deshalb kein Alternative zu den Re-188 markierten MS, die wir regelmäßig zur i.a. Therapie verwenden [1]. Dementsprechend ist auch eine Lu-177 Markierung dieser biologisch abbaubaren Partikeln nicht sinnvoll.

Literatur/References:
1] Wunderlich, G., Drews, A., Kotzerke, J. A kit for labelling of Re-188 HSA Mikrosphären for therapeutic use in nuclear medicine. Appl Radiat Isot 62 (2005) 915-918

Poster:
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D
Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A77

Registration 12.04.2010 14:07, No. 13982


Novel Functionalised Nanoparticles for Application in the Imaging of Cancer Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): DAAD Alumni Meeting ”Tackling the future” , 26.-28.03.2010, Sydney, Australia Registration 06.04.2010 16:32, No. 13965


Tumor imaging using ⁶⁴Cu-labeled peptides Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Seminar, Bio21 Institute, School of Chemistry, University of Melbourne , 25.03.2010, Melbourne, Australia Registration 06.04.2010 16:29, No. 13964


Is there a real need to develop new chelating systems for radioisotopes? Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Seminar, School of Chemistry, Monash University , 22.03.2010, Melbourne, Australia Registration 06.04.2010 16:25, No. 13963

Induction of atherogenic changes in vascular endothelial cells by radiation: role of the receptor for advanced glycation endproducts
Pietzsch, J.
Abstract: kein Abstract verfügbar

Poster:
Inflammation 2010, 27.-30.01.2010, Luxembourg, Luxembourg
Contribution to Proceeding:
Inflammation 2010, 27.-30.01.2010, Luxembourg, Luxembourg
Inflammatory cell signaling mechanisms as therapeutic targets. (Ed. Diederich M). Fondation de Recherche Cancer et Sang, Luxembourg 2010, 114

Registration 06.04.2010 16:16, No. 13962

Influence of novel selective cyclooxygenase-2 (COX-2) inhibitors on low density lipoprotein oxidation
Pietzsch, J.; Pietzsch, F.-J.; Laube, M.; Bergmann, R.; Wuest, F.; Steinbach, J.; Kniess, T.
Abstract: kein Abstract verfügbar

Poster:
Inflammation 2010, 27.-30.01.2010, Luxembourg, Luxembourg
Contribution to Proceeding:
Inflammation 2010, 27.-30.01.2010, Luxembourg, Luxembourg
Inflammatory cell signaling mechanisms as therapeutic targets (Ed. Diederich M). Fondation de Recherche Cancer et Sang, Luxembourg 2010, 210

Registration 06.04.2010 15:46, No. 13961

Fluorine-18 labeling of phosphopeptides: a potential approach for the evaluation of phosphopeptide metabolism in vivo.
Richter, S.; Bergmann, R.; Pietzsch, J.; Ramenda, T.; Steinbach, J.; Wuest, F.
Abstract: Phosphopeptides are very useful reagents to study signal transduction pathways related with cellular protein phosphorylation/dephosphorylation. Phosphopeptides have also been identified as important drug candidates to modulate intracellular signaling mechanisms through targeting phosphotyrosine, phosphoserine, or phosphothreonine residue-binding protein domains. In this report, we describe the development of a convenient method for the mild and sufficient radiolabeling of phosphopeptides with the short-lived positron emitter fluorine-18 (¹⁸F) to allow radiopharmacological studies on phosphopeptide metabolism in vivo by means of positron emission tomography (PET). Radiolabeling was accomplished via conjugation of the N-terminus of polo-box domain (PBD)-binding phosphopeptide H-Met-Gln-Ser-pThr-Pro-Leu-OH with the bifunctional labeling agent N-succinimidyl-4-[¹⁸F]fluorobenzoate ([¹⁸F]SFB) in reproducible isolated radiochemical yields of 25-28%. Radiopharmacological evaluation in vitro and in vivo of radiolabeled phosphopeptide [¹⁸F]FB-Met-Gln-Ser-pThr-Pro-Leu-OH [¹⁸F]-3 and its non-phosphorylated analog [¹⁸F]FB-Met-Gln-Ser-Thr-Pro-Leu-OH [¹⁸F]-4 involved metabolic stability, cell uptake studies, and small animal PET experiments. Radiolabeled phosphopeptide [¹⁸F]-3 showed a remarkable high metabolic stability in vivo compared to the corresponding non-phosphorylated peptide [¹⁸F]-4. The presented method indicates that radiolabeling of phosphopeptides with [¹⁸F]SFB is a promising approach for studying phosphopeptide metabolism in vivo.
Keywords: phosphopeptides; fluorine-18; positron emission tomography (PET)

Biopolymers (PeptideScience) 92(2009)6, 479-488

Registration 25.03.2010 11:31, No. 13920

Radiosynthesis and radiopharmacological evaluation of cyclin-dependent kinase 4 (Cdk4) inhibitors
Koehler, L.; Graf, F.; Bergmann, R.; Steinbach, J.; Pietzsch, J.; Wuest, F.
Abstract: Tumor cells are characterized by their loss of growth control resulting from alterations in regulating pathways of the cell cycle, such as a deregulated cyclin-dependent kinase (Cdk) activity and/or Cdk expression. Appropriately radiolabeled Cdk4 inhibitors are discussed as promising molecular probes for imaging cell proliferation processes and tumor visualization by PET. This work describes the design, synthesis and radiopharmacological evaluation of two ¹²⁴I-labeled Cdk4 inhibitors as potential radiotracers for imaging of Cdk4 in vivo. Treatment of a solution containing labeling precursors with [¹²⁴I]NaI gave radiolabeled Cdk4 inhibitors [¹²⁴I]CKIA and [¹²⁴I]CKIB in radiochemical yields of up to 35%. ¹²⁴I-labeled radiotracers [¹²⁴I]CKIA and [¹²⁴I]CKIB were used in cell uptake studies as well as biodistribution studies in Wistar rats and small-animal PET in tumor-bearing mice. In vitro radiotracer uptake studies in adherent tumor cells using [¹²⁴I]CKIA showed substantial uptake in HT-29 and FaDu cells (750–850 %ID/mg protein [¹²⁴I]CKIA and 900–1000 %ID/mg protein [¹²⁴I]CKIB) after 1 h at 37 °C. Biodistribution of [¹²⁴I]CKIA and [¹²⁴I]CKIB showed rapid blood clearance of radioactivity and an accumulation as well as metabolization in the liver. Both radiotracers were administered intravenously to mouse FaDu xenograft tumor model and imaging studies were performed on a small-animal PET scanner. Both imaging techniques showed only little uptake of both radiotracers in the FaDu tumor xenografts.
Keywords: Iodine-124; Cell cycle; Cyclin-dependent kinase 4 inhibitor; Positron emission tomography (PET)

European Journal of Medicinal Chemistry 45(2010), 727-737

Registration 09.03.2010 16:21, No. 13866

Scavenger receptors are associated with cellular interactions of S100A12 in vitro and in vivo
Hoppmann, S.; Steinbach, J.; Pietzsch, J.
Abstract: Increased plasma levels of S100 proteins and interaction of S100 proteins with receptor for advanced glycation end products (RAGE) have been associated with a number of disease states, including chronic inflammatory processes and atherosclerosis. However, data concerning the role of circulating S100 proteins in these pathologies in vivo are scarce and, furthermore, it is currently not known whether RAGE is the sole receptor for extracellular S100 proteins in vivo. We report a novel methodology using recombinant human S100 proteins radiolabelled with fluorine-18, particularly, ¹⁸F-S100A12, in receptor binding studies and cellular association studies in vitro, and in dynamic small animal positron emission tomography (PET) studies in rats in vivo. Association to both human aortic endothelial cells and macrophages revealed specific binding of ¹⁸F-S100A12 to RAGE, but, furthermore, provides evidence for interaction of ¹⁸F-S100A12 to various scavenger receptors (SR). PET data showed temporary association of ¹⁸F-S100A12 with tissues overexpressing RAGE (e.g., lung), and, moreover, accumulation of ¹⁸F-S100A12 in tissues enriched in cells overexpressing SR (e.g., liver and spleen). Blockade of overall SR interaction by maleylated BSA (malBSA) clearly shows diminished in vivo association of ¹⁸F-S100A12 to these tissues as well as a significant increment of the mean plasma residence time of ¹⁸F-S100A12 (4.8 ± 0.4 h vs. 2.3 ± 0.3 h). The present approach first demonstrates that besides RAGE also scavenger receptors contribute to distribution, tissue association and elimination of circulating proinflammatory S100A12.
Keywords: Maleylated bovine serum albumin; Receptor for advanced glycation endproducts (RAGE); S100 proteins/calgranulins; Scavenger receptors; Small animal positron emission tomography (PET)

International Journal of Biochemistry & Cell Biology 42(2010), 651-661

Registration 09.03.2010 15:39, No. 13863

Effects of posture on regional pulmonary blood flow in rats as measured by PET
Richter, T.; Bergmann, R.; Pietzsch, J.; Közle, I.; Hofheinz, F.; Schiller, E.; Ragaller, M.; van den Hoff, J.
Abstract: Using small animal PET with ⁶⁸Ga-radiolabeled human albumin microspheres (Ga-68-microspheres), we investigated the effect of posture on regional pulmonary blood flow (PBF) in normal rats. This in vivo method is noninvasive and quantitative, and it allows for repeated longitudinal measurements. The purpose of the experiment was to quantify spatial differences in PBF in small animals in different postures. Two studies were performed in anesthetized, spontaneously breathing Wistar rats. Study 1 was designed to determine PBF in the prone and supine positions. Ga-68-microspheres were given to five prone and eight supine animals. We found that PBF increased in dorsal regions of supine animals (0.75) more than in prone animals (0.70; P = 0.037), according to a steeper vertical gradient of flow in supine than in prone animals. No differences in spatial heterogeneity were detected. Study 2 was designed to determine the effects of tissue distribution on PBF measurements. Because microspheres remained fixed in the lung, PET was performed on animals in the position in which they received Ga-68-microsphere injections and thereafter in the opposite posture. The distribution of PBF showed a preference for dorsal regions in both positions, but the distribution was dependent on the position during administration of the microspheres. We conclude that PET using Ga-68-microspheres can detect and quantify regional PBF in animals as small as the rat. PBF distributions differed between the prone and supine postures and were influenced by the distribution of lung tissue within the thorax.
Keywords: pulmonary blood flow; positron emission tomography; ⁶⁸Ga radiolabel; human serum albumin microspheres; prone position; supine position; small animal

Journal of Applied Physiology 108(2010), 422-429

Registration 08.02.2010 11:16, No. 13769

PET-based investigation of cerebral activation following intranasal trigeminal stimulation
Hummel, T.; Oehme, L.; van den Hoff, J.; Gerber, J.; Heinke, M.; Boyle, Julie A.; Beuthien-Baumann, B.
Abstract: The present study aimed to investigate cerebral activation following intranasal trigeminal chemosensory stimulation using O15-H2O-PET. A total of 12 healthy male participants underwent a PET scan presented with four scanning conditions; two left-sided intranasal CO2-stimuli and two matched baseline conditions consisting of odorless air. CO2 was used as it produces burning and stinging sensations. Stimulation started 20 s before intravenous injection of the isotope and lasted for the first 60 s of the 5 min scan time. A comparison between CO2 and baseline showed a pronounced activation of the trigeminal projection area at the base of the postcentral gyrus (primary and secondary somatosensory cortex) which was more intense for the right hemisphere, contralateral to the side of stimulation. In addition, activation was also found in the piriform cortex which is typically activated following odor presentation and thus thought of as primary olfactory cortex. In conclusion, and in line with previously published work, our data suggest that intranasal trigeminal stimulation not only activates somatosensory projection areas, but that it also leads to activation in cerebral areas associated with the processing of olfactory information. This may be interpreted in terms of the intimate relation between the intranasal chemosensory systems.
Keywords: pain • stinging • nose • anosmia • olfaction • positron emission tomography • 15O-H2O

Human Brain Mapping 30(2009), 1100-1104

Registration 08.02.2010 10:49, No. 13767


RP-HPLC zur Trennung von DNA Bausteinen Förster, C. Abstract: kein Abstract verfügbar Lecture (others): 3. Workshop Möglichkeiten und Grenzen der HPLC in den Lebenswissenschaften, 29.01.2010, Dresden- Rossendorf, D Registration 08.02.2010 10:34, No. 13766

Effects of cold sphere walls in PET phantom measurements on the volume reproducing threshold
Hofheinz, F.; Dittrich, S.; Pötzsch, C.; van den Hoff, J.
Abstract: We studied quantitatively the effects of the discontinuity introduced in an otherwise homogeneous background by the cold walls of the standard spherical glass inserts commonly used in phantom measurements for calibration of
threshold-based approaches to volumetric evaluation of PET investigations. We concentrated especially on the question of threshold-based volume determination. We computed analytically the convolution of an isotropic Gaussian point-spread function with the insert geometry (hot sphere + cold wall + warm background) and derived the theoretical background dependence of the volume reproducing threshold. This analysis shows a clear wall-related reduction of the optimal threshold with increasing background. The predictions of our theoretical analysis were verified in phantom measurements at background fractions between 0 and 0.29. Defining the background-corrected relative threshold T = T_abs−B ./. A−B (T_abs: absolute volume reproducing threshold, A: measured activity at centre, B: background), we find that for a wall-less sphere T is independent of the background level. In the presence of cold walls, T drops (for not too small spheres, where recovery at the centre approaches 100%) from about 43% at B/A = 0 to about 25% at B/A = 0.5. Applying these thresholds towall-less spheres leads to sizeable overestimates of the true volumes (43% at B/A = 0.5 for a sphere of 6 ml volume). We conclude that phantom measurements with standard sphere inserts for calibration of optimal thresholding algorithms introduce a systematic bias if performed at finite background levels. The observed background dependence is an artefact of the measurement procedure and does not reflect the conditions present in actual patient investigations.

Physics in Medicine and Biology 55(2010), 1099-1113

Registration 08.02.2010 10:22, No. 13765


Radiomarkierte Verbindungen: Anwendungsmöglichkeiten in Analytik und Medizin Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Freie Universität Berlin, Institut für Chemie und Biochemie, 03.02.2010, Berlin, Deutschland Registration 08.02.2010 09:32, No. 13763


Molekulare Bildgebung zum Aufspüren von Tumorerkrankungen Stephan, H. Abstract: kein Abstract verfügbar Invited lecture (Conferences): Hochschule Görlitz/Zittau, 05.11.2009, Zittau, Deutschland Registration 08.02.2010 09:28, No. 13762

Improved Multimodality Imaging Using Alginate Molding in Xenograft Tumor Models
Strobel, K.; Bergmann, R.; Meister, S.; van den Hoff, J.; Pietzsch, J.
Abstract: Purpose: To allow for reproducible rodent positioning using molding in multimodal tomographic imaging (positron emission tomography (PET), magnetic resonance imaging/spectroscopy (MRI/MRS)), minimization of magnetic field inhomogeneity during MRI investigations of peripheral structures, and reproducible positioning for subsequent histological sectioning of the separated tumor.
Materials and Methods: Chemical shift imaging (CSI) studies were carried out using phantoms and NMRI nu/nu mice bearing subcutaneous tumors. For embedding, three different materials were used: i) alginate, ii) gelatin, and iii) a mixture of wheat flour and salt. The animals were placed in an animal chamber including position markers visible by MRI and PET. The frozen embedded explanted tumors were sliced and examined autoradiographically as well as histologically.
Results: Alginate showed a substantial improvement of magnetic field homogeneity and histological sectioning was superior to the other methods. This embedding led to a significant reduction of the full width at half maximum (FWHM) of the water peak in the peripheral rim of the tumor in comparison to the same peak FWHM without embedding (41+-10 Hz vs. 80+-20 Hz).
Conclusions: Our research shows that animal positioning in an imaging chamber together with alginate embedding allows high quality multimodality investigations including coregistration of MRI/MRS, PET, and histological images.

Journal of Magnetic Resonance Imaging 31(2010), 747-752

Registration 25.01.2010 11:26, No. 13699

Analysis of non-protein amino acids as specific markers of protein oxidation: the use of N(O,S)-ethoxycarbonyl ethyl ester and N(O,S)-ethoxycarbonyl trifluoroethyl ester derivatives and GC-MS
Pietzsch, J.; Pietzsch, F.-J.; Kopprasch, S.
Abstract: Oxidative modification of proteins is widely regarded as a crucial event in the pathogenesis of various inflammatory and metabolic diseases. In this line, a sensitive and specific GC-MS methodology using either N(O,S)-ethoxycarbonyl ethyl amino acid esters (ECEE) or N(O,S)-ethoxycarbonyl trifluoroethyl amino acid esters (ECEE-F3) for rapid and sensitive determination of modified amino acid side chain residues as specific oxidation markers in proteins has been developed.
Both ECEE and ECEE-F3 derivatives are formed by the unlabored reaction of amino acids with ethyl chloroformate plus ethanol or trifluoroethanol plus pyridine. The key steps of the methodology involve enzymatic hydrolysis of target proteins to prevent decomposition of oxidation products during hydrolysis and uniquely rapid derivatization of modified amino acids completing sample preparation for GC within a few minutes in aqueous solution at room temperature. The use of this methodology for assessing (glyc)oxidative damage in low density lipoprotein apolipoprotein B-100 (apoB-100) recovered from human plasma and various inflammatory compartments has been demonstrated. The observations provided quantitative chemical evidence for (glyc)oxidative processes in several inflammatory and metabolic diseases.

Trends in Chromatography 5(2009), 15-20

Registration 15.01.2010 12:09, No. 13625

Mild glykatierte Lipoproteine > geringer Dichte (LDL) verstärken die Adipogenese von 3T3-L1-Zellen
Neuber, C.; Hoppmann, S.; Pietzsch, J.
Abstract: Diabetes mellitus Typ 2 (T2D) und Adipositas sind zwei wichtige Facetten des Metabolischen Syndroms. Ein pathobiochemisches Bindeglied zwischen beiden Erkrankungen ist möglicherweise die Bildung glykatierter Lipoproteine geringer Dichte (glykLDL), einer frühen Form der advanced glycation endproducts (AGE). Ziel der Untersuchung war es, zu zeigen, ob und über welche Mechanismen glykLDL im Vergleich zu nativen LDL (nLDL) einen Einfluss auf die Adipogenese ausüben.
Durch Inkubation humaner LDL mit Glukose (200 mmol/L, 37°C, 144 h) konnten glykative Veränderungen am Apolipoprotein B-100 der LDL-Partikel erreicht werden, die vergleichbar zu den bei Patienten mit manifestem T2D in vivo auftretenden Veränderungen von LDL sind. Als Modell für die humane Adipogenese diente die hormoninduzierte Umwandlung muriner 3T3 L1-Präadipozyten zu Zellen, die morphologisch und physiologisch reifen Adipozyten ähneln. Mittels quantitativer RT PCR und Western Blotting wurde der Einfluss glykatierter LDL auf die mRNA Expression und Proteinbiosynthese verschiedener (Prä )Adipozytenmarker sowie potentieller glykLDL Rezeptoren untersucht. Darüber hinaus erfolgten Untersuchungen zur zellvermittelten Aufnahme von Fluor-18-markierten LDL.
Es konnte gezeigt werden, dass glykLDL die Lipideinlagerung, als Zeichen der Differenzierung von Präadipozyten zu Adipozyten, signifikant verstärkten, während es unter dem Einfluss der nLDL zu einer signifikant verminderten Adipogenese kam, die sich tendenziell auch in einer verminderten mRNA-Expression des Adipozytenmarkers PPAR2 zeigte. Als potenzielle Mediatoren der LDL-induzierten Effekte wurden sowohl der LDL-Rezeptor (LDLR), der Rezeptor für AGE (RAGE) als auch verschiedene Scavenger-Rezeptoren (SR) näher charakterisiert. Die Untersuchungen mit Fluor-18-markierten LDL zeigten, dass Präadipozyten etwa zehnmal mehr nLDL bzw. glykLDL internalisierten als Adipozyten, wobei die Bindung und Internalisierung von nLDL etwa um den Faktor zwei über der von glykLDL lag. Dies deutet auf eine verminderte Affinität der glykLDL beispielsweise zum LDLR hin. Obwohl glykLDL in vitro und in vivo Liganden für RAGE sind, spielte RAGE bei der Differenzierung von 3T3-L1-Zellen nur eine untergeordnete Rolle. Die Differenzierung von Präadipozyten zu Adipozyten ging mit einer unveränderten SR-B1- sowie mit einer verminderten LDLR-, RAGE-, CD36- und LOX-1-(lectin like oxidized LDL-1)-Rezeptor-Synthese einher. In Kombination mit den Ergebnissen der Zellaufnahmestudien wird deutlich, dass vorrangig der LDLR, der SR-B1 und möglicherweise auch LOX-1 für die Internalisierung der LDL von Bedeutung sind.
Als mögliche intrazelluläre Mechanismen für die glykLDL-induzierte Stimulation der Lipideinlagerung werden die Aktivierung des NF-κB oder des nukleären Leber-X-Rezeptors (LXR) diskutiert. Aus den Ergebnissen der vorliegenden Arbeit lässt sich schlussfolgern, dass bereits mild glykatierte LDL-Partikel die Adipogenese verstärken.

Poster:
25. Jahrestagung der Deutschen Adipositas-Gesellschaft und Herbsttagung der Deutschen Diabetes-Gesellschaft, 05.-07.11.2009, Berlin, D
Conference abstract in ref. journal:
AdipositasSpektrum 5(2009), 67

Registration 15.01.2010 11:49, No. 13624

The impact of FMISO hypoxic volume on local control after single dose irradiation in FADU HNSCC in nude mice
Schütze, C.; Bergmann, R.; Mosch, B.; Yaromina, A.; Hessel, F.; Krause, M.; Thames, H. D.; Zips, D.; Mäding, P.; Baumann, M.; Beuthien-Baumann, B.
Abstract: kein Abstract verfügbar

Poster:
ICTR 2009 - Fourth International Conference on Translational Research in Radiation Oncology, 11.-13.03.2009, Genf, Schweiz

Registration 14.01.2010 16:22, No. 13615

Radiolabeled Cdk4/6 inhibitors for molecular imaging of tumors
Graf, F.; Köhler, L.; Mosch, B.; Pietzsch, J.
Abstract: Overexpression of cell-cycle regulating cyclin-dependent kinases 4 and 6 (Cdk4/6) and deregulation of Cdk4/6-pRb-E2F pathway are common aspects in human tumors. The aim of our study was the evaluation of pyrido[2,3 d]pyrimidin-7-one derivatives (CKIA and CKIE) concerning their efficacy and suitability as small molecule Cdk4/6 inhibitors and, after iodine-124 ([124I]CKIA) or fluorine-18 ([18F]CKIE) radiolabeling, as radiotracers for Cdk4/6 imaging in tumors by positron emission tomography (PET).
CKIA and CKIE were analyzed concerning their biological properties (effects on cell growth, cell cycle distribution, Cdk4/6 mediated pRb-Ser780 phosphorylation, mRNA expression of pRb affected genes E2F-1 and PCNA) and radiopharmacological properties (cellular radiotracer uptake and PET studies) using human tumor cell lines HT-29, a colorectal adenocarcinoma cell line, FaDu, a head and neck squamous cell carcinoma cell line, and THP-1, an acute monocytic leukemia cell line, as well as phorbol ester TPA-activated THP-1 cells, as model of tumor-associated macrophages.
CKIA and CKIE were identified as potent inhibitors of Cdk4/6-pRb-E2F pathway due to decreased Cdk4/6 specific phosphorylation at pRb Ser780 and downregulation of E2F-1 and PCNA mRNA expression in HT-29, FaDu and THP-1 tumor cells. This resulted in arrest of these tumor cell lines in G1 phase of the cell cycle and growth inhibition. Otherwise, in non-proliferating TPA-activated THP-1 macrophages no change of cell-cycle distribution after treatment with CKIA and CKIE was observed. Furthermore, TPA-activated THP-1 macrophages showed lower Cdk4 mRNA and protein levels, than other tumor cell lines. In vitro radiotracer uptake studies using [124I]CKIA and [18F]CKIE demonstrated tumor cell uptake, which could be blocked with both nonradioactive CKIA and CKIE. However, THP-1 macrophages showed similar radiotracer uptake like other tumor cells. Preliminary small animal PET studies in mouse tumor xenograft models further analyzed the hypothesis that radiolabeled Cdk4/6 inhibitors are suitable tracers for molecular imaging of tumors

Conference abstract in ref. journal:
Cancer Microenvironment 2(2009), S185
Poster:
5th International Conference On Tumor Microenvironment: Progression, Therapy & Prevention, 20.-24.10.2009, Versailles, France

Registration 14.01.2010 15:17, No. 13613

Irradiation-induced changes in metabolism and metastatic properties of melanoma cells
Mosch, B.; Müller, K.; Steinbach, J.; Pietzsch, J.
Abstract: As it is known that irradiation can influence cellular metabolism it is conceivable that it can induce metabolic changes which lead to a predisposition of certain cells to show enhanced survival, migratory activity and metastasis. The aim of this study was to investigate short term and long term irradiation effects on proliferation and metabolism of melanoma cells in vitro and their ability to form metastases in vivo.
B16-F10 melanoma cells were irradiated with different doses of X-ray irradiation in the range of 1 to 20 Gy. One, two, and three days (short term effects) and, furthermore, 7, 14 and 21 days (long term effects) after treatment cells were analyzed concerning cell growth, proliferation, viability, glucose and amino acid transport. Additionally, we performed in vivo studies in a syngeneic mouse model to analyze the capability of irradiated melanoma cells to form lung metastases.
The analysis of short term effects showed decreased cell growth, viability and arrest in the G2/M phase of the cell cycle while glucose transport is increased. Long term effects involve recovered proliferation, accompanied by increased glucose transport and decreased viability and amino acid transport. In vivo studies showed loss of metastasis immediately after irradiation and reduced metastasis if cells were allowed to recover proliferation before injection.
We conclude that melanoma cells as short term response to irradiation show cell cycle arrest and impairment in growth and viability. Three days after irradiation compensatory mechanisms start, leading to recovered growth within three weeks. Studies concerning metabolic properties indicate that a subpopulation of surviving melanoma cells compensate for the initial irradiation-induced damage possibly by metabolic modulations such as increase in glycolysis. As metastasis in vivo is impaired beyond recovered cell proliferation, the role of adjusted cell metabolism and additional extrinsic factors is strongly suggested.

Conference abstract in ref. journal:
Cancer Microenvironment 2(2009), S150-S151
Poster:
5th International Conference on Tumor Microenvironment: Progression, Therapy & Prevention, 20.-24.10.2009, Versailles, France

Registration 14.01.2010 15:02, No. 13612

Changes in metabolism and metastatic properties of melanoma cells after X-ray irradiation
Mosch, B.; Müller, K.; Steinbach, J.; Pietzsch, J.
Abstract: Background: Malignant melanoma has the ability to form metastases at very early stages and in addition to surgical resection treatment involves immunotherapy, chemotherapy and also radiotherapy. As it is known that irradiation can influence cellular metabolism it is conceivable that it can induce metabolic changes which lead to a predisposition of certain cells to show enhanced survival, migratory activity and metastasis. The aim of this study was to investigate short term and long term irradiation effects on metabolism and proliferation of irradiated melanoma cells in vitro and their ability to form metastases in vivo.
Material and methods: B16-F10 melanoma cells were irradiated with different doses of X-ray irradiation in the range of 1 to 20 Gy. One, two, and three days (short term effects) and, furthermore, 7, 14 and 21 days (long term effects) after treatment cells were analyzed concerning cell growth, viability, proliferation, cell cycle distribution, glucose and amino acid transport. Additionally, we performed in vivo studies in a syngeneic mouse model to analyze the capability of irradiated melanoma cells to form lung metastases.
Results: The analysis of short term effects showed decreased cell growth, viability and arrest in the G2/M phase of the cell cycle. Long term effects involve increase in proliferation, cell growth and glucose uptake but still decreased viability and amino acid transport. Our in vivo studies showed no formation of lung metastases when cells were irradiated before injection. If irradiated cells were allowed to recover for 2 weeks before injection, mice again developed lung metastases although to a lesser extent than control mice.
Conclusions: We conclude that melanoma cells as short term response to irradiation show cell cycle arrest and decrease in cell viability, growth and metabolic properties. One to three weeks after irradiation, the re-start of proliferation and recurrence of metabolic properties such as glucose uptake indicate that a subpopulation of surviving melanoma cells compensate for the initial irradiation-dependent damage possibly by metabolic modulations such as increase in glycolysis. Furthermore, in vivo studies reveal that irradiated melanoma cells are able to resume their metastatic potential within two weeks. As lung metastasis is lower when using recovered cells versus untreated cells, the role of additional mechanisms is strongly suggested.

Conference abstract in ref. journal:
European Journal of Cancer 7(2009), 587
Poster:
ECCO 15 - 34th ESMO Multidisciplinary Congress, 20.-24.09.2009, Berlin, D

Registration 14.01.2010 14:54, No. 13611

Influence of irradiation on the metabolism of melanoma cells and metastasis in mice.
Mosch, B.; Müller, K.; Steinbach, J.; Pietzsch, J.
Abstract: Irradiation is a powerful tool for the therapy of solid tumors. But often single cells elude this treatment and constitute a basis for recurrence of the primary tumor and formation of metastases. Until today it is unclear which properties enable some cells to this. One possible explanation could be predicted on irradiation-dependent metabolic changes which lead to a predisposition of certain cells to show enhanced survival and migratory activity. The aim of this study was to investigate metabolic properties and proliferation of irradiated melanoma cells in vitro and their ability to form metastases in vivo.
We applied different single-dose X-ray irradiation (200kV X-rays, 0.5mm Cu, ~ 1.2 Gy min-1; 1, 2, 5, 7, 10, and 20 Gy) to murine B16-F10 melanoma cells. At particular times we analyzed cell viability, growth properties and cell cycle distribution. Furthermore, we analyzed the cellular uptake of the radiotracers 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and 3-O-methyl-[18F]fluoro-L-DOPA ([18F]OMFD), providing information about the glucose and amino acid metabolism before and after irradiation. Additionally, we performed in vivo studies in a syngeneic mouse model to analyze the capability of irradiated melanoma cells to form lung metastases after injection into the tail vein of NMRI mice.
In a dose-dependent manner we detected a decrease in cell viability and cell growth properties starting 3 days after irradiation. Decreased cell growth persists up to 1 week for 5 Gy irradiated cells and up to 2 weeks for 10 Gy irradiated cells. After this periods growth of irradiated cells is comparable to control cells. Cell cycle analyses showed an increase in G2/M phase cells up to 3 days after X-ray followed by an increase in S phase cells 6 days after X-ray. At this point of time uptake of radiotracers was altered inasmuch as [18F]FDG uptake decreased, whereas [18F]OMFD uptake increased. Our in vivo studies showed a loss of lung metastases when cells were irradiated (10 Gy) before injection. If irradiated cells were allowed to recover for 2 weeks before injection, mice again developed lung metastases although to a lesser extent than control mice.
We conclude that irradiation of melanoma cells leads to a dose-dependent decrease in cell viability, growth properties and glucose uptake. Cell cycle analyses suggest an arrest in the G2/M phase. One week after irradiation compensating mechanisms of these effects seems to start as indicated by the uptake of [18F]OMFD, the increase in S phase cells and recovered growth of low-dose (5 Gy) irradiated cells. Two weeks after irradiation cell growth is completely recovered in vitro. Accordingly, in vivo studies reveal that irradiated melanoma cells are able to resume their metastatic potential within two weeks, even though to a lesser extent than before irradiation. The questions why and how some cells modulate their metabolism and thus re-start proliferation and why metastasis is influenced in vivo although growth properties are recovered in vitro, need to be further investigated.

Poster:
2nd Workshop on Radiation and Multidrug Resistance via the Tumor Microenvironment, 09.-10.02.2009, Dresden, D

Registration 14.01.2010 14:45, No. 13610


Detection and quantification of hypoxia in xenotransplanted human squamous cell carcinoma Bergmann, R.; van den Hoff, J.; Pietzsch, J.; Strobel, K.; Mosch, B.; Schütze, C.; Brüchner, K.; Hofheinz, F.; Beuthien-Baumann, B. Abstract: kein Abstract verfügbar Poster: World Molecular Imaging Conference, 10.-13.09.2008, Nizza, Frankreich Registration 14.01.2010 14:40, No. 13609

Pre-treatment FMISO hypoxic volume is a significant prognostic factor for local control after irradiation of FaDu HNSCC xenografts
Schütze, C.; Bergmann, R.; Mosch, B.; Yaromira, A.; Hessel, F.; Krause, M.; Thames, H. D.; Zips, D.; Mäding, P.; Baumann, M.; Beuthien-Baumann, B.
Abstract: Objective: To investigate whether pre-treatment FMISO hypoxic tumour volume (HV) adds significant information about radiotherapy outcome in FaDu human squamous cell carcinoma (hSCC) in nude mice.
Materials and Methods: The hSCC cell line FaDu was transplanted subcutaneously into the hind leg of NMRI nude mice. Seventy animals entered the study at tumour volumes ranging from 165-343 mm³. [18F]fluoromisonidazole ([18F]FMISO)-PET scanning was performed under anesthesia (9% desflurane in 40% oxygen/air) on a dedicated animal PET scanner (MicroPET® P4, CTI Molecular Imaging Inc, measured attenuation correction, 11 MBq 18FMISO i.v., list mode acquisition for 30 min after 210 min p.i). The regions of interest (ROI) include the FMISO positive hypoxic volume, the mean, the maximum concentration (ROVER software, ABX GmbH, Radeberg, Germany). After an initial FMISO-PET (day 0) the tumours were stratified according to the median hypoxic volume (HV) for single dose irradiation with either 25 Gy (tumour control probability, TCP20) or 35 Gy (TCP80) under normal blood flow conditions using 200 kV X-rays (0.5 mm Cu, ~ 1.2 Gy min-1). The endpoint was time to local failure. Five animals are currently still in follow up.
Results: Tumour local control rate after irradiation with 25 Gy was lower than after irradiation with 35 Gy (22% vs. 69%, log rank p<0.0001). HV ranged from 38-353 mm³. Median HV was 112 mm³ (95%CI: 92; 128 mm³). In tumours with HV less than the median, local control was 33% after 25 Gy vs. 82% after 35 Gy (p=0.001) and in tumours with HV above the median 15% after 25 Gy vs. 53% after 35 Gy (p=0.0005). Multivariate Cox analysis revealed a significant effect of hypoxic volume treated either as a continuous (p=0.009) or a dichotomic variable (stratification by median HV) (p=0.039) when corrected for dose and tumour volume effects. Dose had a significant impact on hazard of recurrence (p<0.0005), whereas total tumour volume showed no effect (p=0.5).
Conclusions: Hypoxic volume is a significant predictor of tumour control after irradiation with high single doses in a single tumour line. This supports the hypothesis that pre-treatment FMISO-PET may provide useful information for heterogeneous radiation dose prescription in sub volumes of individual tumours. Confirmatory investigations using other tumour models and fractionated radiotherapy are warranted.
This work was performed within the 6th framework EU-project BioCare, proposal# 505785.

Conference abstract in ref. journal:
Radiotherapy and Oncology 88(2008), S102
Poster:
27th conference of the European Society for Therapeutic Radiology and Oncology (ESTRO), 14.-18.09.2008, Göteborg, Schweden

Registration 14.01.2010 14:29, No. 13608

Neuronal Aneuploidy in Health and Disease: A Cytomic Approach to Understand the Molecular Individuality of Neurons
Arendt, T.; Mosch, B.; Morawski, M.
Abstract: Structural variation in the human genome is likely to be an important mechanism for neuronal diversity and brain disease. A combination of multiple different forms of aneuploid cells due to loss or gain of whole chromosomes giving rise to cellular diversity at the genomic level have been described in neurons of the normal and diseased adult human brain. Here, we describe recent advances in molecular neuropathology based on the combination of slide-based cytometry with molecular biological techniques that will contribute to the understanding of genetic neuronal heterogeneity in the CNS and its potential impact on Alzheimer´s disease and age-related disorders
Keywords: alu-repeats, Alzheimer´s disease, cell cycle, cell death, chromosomal mosaicism, in situ hybridisation, laser capture microdissection, neurodegeneration, slide-based cytometry

International Journal of Molecular Sciences 10(2009), 1609-1627

Registration 14.01.2010 11:53, No. 13607

Cyclin-dependent kinases Cdk4 and Cdk6: targets for cancer treatment and visualization.
Graf, F.; Köhler, L.; Mosch, B.; Steinbach, J.; Pietzsch, J.
Abstract: Cancerogenesis is closely associated with deregulated cell proliferation and, consequently, aberrant cell cycle control. The first phase of the cell cycle (G1) comprises important steps for initiation of DNA replication and subsequent cell division. The activation and coordination of G1 phase is accomplished by enzymes of serine/threonine kinase family. As members of this protein family and important regulators of early cell cycle machinery, cyclin-dependent kinases 4 and 6 (Cdk4/6) associate with regulatory protein cyclin D, and phosphorylate retinoblastoma protein pRb. Hyperphosphorylated pRb dissociates from E2F transcription factors and triggers transcription of genes required for further G1 phase progression. Hence, Cdk4/6 were identified as essential and critical activators of G1 phase in human embryogenesis, homeostasis, and cancer development; G1 phase progression in cell cycle by phosphorylation of retinoblastoma protein pRb and thua, activation of gene transcription.
In 80% of human tumors the Cdk4/6-cyclin D/ pRb/ E2F pathway is altered provoked by multiple mechanisms. In tumor formation, hyperactivation of Cdk4/6 is often a result of overexpression, silencing, and epigenetic alteration of their regulators or substrates. On the other hand, disruption of Cdk4/6-associated cell cycle control in cancer is also caused directly by mutations and amplification of Cdk4/6 themself. Cdk4/6 protein amplification was found in a wide spectrum of solid tumors and blood cell cancer, e.g., gliomas, lymphomas, melanomas, carcinomas, and leukemias. In consequence, Cdk4/6 were considered to be attractive targets for pharmacological anti-cancer drug development. In the recent years, Cdk4/6 inhibitors of high potency and selectivity against other kinases, especially other cyclin-dependent kinases, were developed and evaluated. One of these compounds, a pyrido[2,3-d]pyrimidine-7-one derivative currently is undergoing clinical trials for cancer therapy.
Though, potent and selective pyrido[2,3-d]pyrimidine-7-one Cdk4/6 inhibitors are not only promising new compounds for cancer therapy, but also for visualization and functional characterization of human tumors. Radiolabeled Cdk4/6 inhibitors could be of particular interest for the assessment of Cdk4/6 protein status and Cdk4/6 activity of human tumors by non-invasive imaging technique positron-emission-tomography (PET). PET affords the opportunity of three-dimensional imaging of physiological processes in vivo. Additionally, PET would provide pharmacological data of radiolabeled Cdk4/6 inhibitors, which may help to estimate the applicability of the compounds for tumor therapy. In this regard, positron-emitting Cdk4/6 inhibitors were designed, synthesized and characterized in our institute for the first time. The radiolabeled compounds and their nonradioactive analogs are based on the lead structure of pyrido[2,3-d]pyrimidine-7-one CKIA.
First, iodine-containing pyrido[2,3-d]pyrimidine-7-one derivatives CKIA and CKIB were evaluated concerning their efficacy and suitability as Cdk4/6 inhibitors in human tumor cell lines. The compounds showed both significant and specific inhibition of tumor cell proliferation and G1 phase arrest by targeting the Cdk4/6-cyclin D/ pRb/ E2F signaling pathway [2]. The iodine substituent of CKIA and CKIB represents an attractive site for an isotopic substitution with the positron emitter iodine-124 (124I). 124I-labeled Cdk4/6 inhibitors [124I]CKIA and [124I]CKIB were evaluated concerning their radiopharmacological properties in cellular radiotracer uptake studies, biodistribution studies, and small animal PET studies in NMRI nu/nu mice bearing the human squamous cell carcinoma tumor FaDu [3]. With 4.18 d half-life, 124I affords extended radiopharmacological evaluation and imaging studies using PET. Nevertheless, high positron energy and minor positron emission (26%) are disadvantages, especially for the resolution of PET images. ....

OncoPost & OncoPeople The official Newspaper of the ECCO 15 – 34th ESMO Congress 3(2009), 10

Registration 18.12.2009 14:42, No. 13524

New fluorine-18 radiolabeled Cdk4/6 inhibitors: potential radiotracers for tumor imaging by positron emission tomography.
Graf, F.; Köhler, L.; Mosch, B.; Pietzsch, J.
Abstract: Background
Cyclin-dependent kinases 4 and 6 (Cdk4/6) are important components of cell cycle activation in G1 phase and play critical roles in dysfunction of growth control during cancerogenesis. The aim of our study was the evaluation of new fluorine containing pyrido[2,3 d]pyrimidin-7-one derivatives (CKIC, CKID and CKIE) concerning their efficacy and suitability as Cdk4/6 inhibitors and, after fluorine-18 radiolabeling, as radiotracers for imaging of tumors by positron emission tomography (PET).

Materials and methods
Small molecule inhibitors CKIC, CKID and CKIE were analyzed concerning their biological and radiopharmacological properties in human tumor cell lines HT-29, FaDu and THP-1. Cell cycle distribution of cells was determined by flow cytometry DNA analysis and effects on cell growth were measured. Phosphorylation of retinoblastoma protein (pRb) at Ser780 was analyzed by Western blotting. mRNA expression of the pRb affected genes E2F-1 and PCNA was measured with quantitative RT-PCR. Stability and radiotracer uptake studies with [18F]CKIE were performed.

Results
Cell cycle analyses showed a concentration-dependent (50 nM to 10 µM) increment of percentage of tumor cells in G1 phase after 24 h of incubation with CKIC, CKID and CKIE, with CKIE to be more potent than CKIC and CKID. Cell growth studies indicated reduced tumor cell numbers after 48 h of treatment with 1 µM (< 75%) and 10 µM (< 30%) CKIE and 10 µM (< 70%) CKIC or respectively CKID. Cdk4 specific phosphorylation at pRb Ser780 is decreased in a concentration dependent manner after 24 h of incubation with CKIE. Downregulation of E2F-1 and PCNA mRNA expression could be demonstrated after treatment with CKIE. [18F]CKIE indicated high stability in physiological buffer and cell culture medium. Cellular radiotracer uptake using [18F]CKIE increased with time amounting to 46.3±11.2 %ID/mg protein in HT-29 and 46.2±13.8 %ID/mg protein in FaDu cells, respectively, after 60 min at 37°C. Uptake of [18F]CKIE could be blocked with nonradioactive CKIE dependent on concentration (e.g., 23.5±3.7 %ID/mg protein with 5 µM CKIE after 60 min at 37°C).

Conclusion
CKIE was identified as the most potent fluorine containing pyrido[2,3 d]pyrimidin-7-one derivative analyzed in our study causing arrest of tumor cells in G1 phase due to inhibition of the Cdk4/6/ pRb/ E2F pathway. In vitro radiotracer uptake studies using [18F]CKIE demonstrated tumor cell uptake, which is an important prerequisite for further PET studies in tumor-bearing mice.

Lecture (Conference):
European Cancer Organisation (ECCO) 15 – 34th European Society for Medical Oncology (ESMO) Multidisciplinary Congress, 20.-24.09.2009, Berlin, D
Conference abstract in ref. journal:
European Journal of Cancer Suppl. 7(2009)2, 120-121

Registration 16.12.2009 15:31, No. 13509

Neue tetradentate S4-Liganden auf der Basis verbrückter Dimercaptomaleinsäurederivate (DMMS) zur stabilen Komplexierung von Re-188
Förster, C.; Pietzsch, H.-J.; Steinbach, J.
Abstract: Das Ziel dieser Forschungsarbeiten ist die Entwicklung eines neuen bifunktionellen Chelatorsystemes für eine stabile Komplexierung thiophiler Radiometallnuklide wie Re 188 oder Tc 99m. Neben der Radionuklidfixierung soll dieses Ligandsystem reaktive Zentren (z. B. Aktivester, Maleinimid, Isothiocyanat) zur kovalenten Bindung an verschiedene zielsuchende Einheiten (Antikörper, -fragmente, Peptide, usw.) besitzen. Je nach verwendetem Radionuklid und gebundenem biologisch aktiven Adressmolekül können verschiedene Krankheitsbilder diagnostiziert (Tc-99m) und therapiert (Re 188) werden.
Ausgehend von Verbindung 1 können über die Bildung des Anhydrids 3 und anschließen-der Reaktion mit sekundären Aminen (u. a. Morpholin, 1 Aza-kronenether) unter-schiedliche thiolgeschützte Derivate 4 synthetisiert werden. Hierbei besteht die Möglichkeit, mittels ent-sprechender Amine die pharmakologischen Eigenschaften des späteren Konjugates zu beeinflussen. Die Ausbeuten bis Verbindung 4 sind nahezu quantitativ. Durch Überführung von 4 in das Carbonsäurechlorid, Verbrückung mit boc-geschütztem Norspermidin (Ausbeute 72 %) und Entschützung der einzelnen Schutzgruppen (quant.) erhält man die tetradendaten Liganden 6.
Es gelang zudem, dieses Ligandsystem durch die Reaktion von Bernstein-säureanhydrid mit dem sekundären Amin und Überführung der terminalen Carboxylgruppe in einen Aktivester an eine 5‘-hexylamin-modifizierte DNA zu binden. Beginnende radioaktive Markierungsstudien mit Tc-99m und Re-188 werden zeigen, ob diese 188Re-DMMS-DNA-Konjugate für etwaige Pretargeting-Ansätze zur Therapie von Tumorerkrankungen verwendet werden können.

Poster:
GDCh-Wissenschaftsforum Chemie 2009, 30.08.-02.09.2009, Frankfurt am Main, D

Registration 16.12.2009 15:23, No. 13508

Radiolabelling of proteins with fluorine-18 via click chemistry
Ramenda, T.; Knieß, T.; Bergmann, R.; Steinbach, J.; Wüst, F.
Abstract: The study describes for the first time the application of Cu(I)-mediated 1,3-dipolar [3+2]cycloaddition for the labelling of proteins with the short-lived positron emitter fluorine-18 as exemplified with azide-functionalized human serum albumin (HSA).

Chemical Communications 48(2009), 7521-7523

Registration 15.12.2009 16:09, No. 13504

Modifizierung von radioaktiv markierbaren, komplementären L-Oligonukleotiden zur Beeinflussung ihrer Pharmakokinetik für Pretargeting-Technologien
Förster, C.; Bergmann, R.; Schubert, M.; Közle, I.; Walther, M.; Pietzsch, H.-J.; Vonhoff, S.; Klussmann, S.; Pietzsch, J.; Steinbach, J.
Abstract: kein Abstract verfügbar

Lecture (Conference):
17. Jahrestagung der AG Radiochemie/Radiopharmazie der DGN, 24.-26.09.2009, Schellerhau, D

Registration 10.12.2009 11:15, No. 13490

Influence of irradiation on metabolism and metastatic potential of B16-F10 melanoma cells
Mosch, B.; Müller, K.; Steinbach, J.; Pietzsch, J.
Abstract: Purpose:
To analyse short term and long term X-ray irradiation effects on proliferation, viability, glucose and amino acid uptake of murine melanoma cells in vitro and metastasis in vivo.

Materials and methods:
B16-F10 melanoma cells were irradiated with different doses of X-ray irradiation (200 kV) in the range from 1-20 Gy. One, two and three days respectively 7, 14 and 21 days after treatment cells were analysed concerning cell growth, viability, proliferation, cell cycle distribution, glucose and amino acid transport. Moreover the capability of the cells for in vivo metastasis was examined.

Results:
As short term response on irradiation we detected decreased cell growth, viability and arrest in the G2/M phase of the cell cycle. Long term response involves re-start of proliferation, increased cell growth and glucose uptake but still decreased viability and amino acid transport. In vivo metastasis is lost immediately after irradiation and regained to a low extent beyond two weeks time for recurrence of cells before injection.

Conclusions:
In vitro data suggest that surviving melanoma cells compensate the initial irradiation-dependent damage of proliferation within three weeks possibly by increase in glucose uptake. For metastasis in vivo the role of additional mechanisms is strongly suggested.

International Journal of Radiation Biology 85(2009)11, 1002-1012

Registration 25.11.2009 11:42, No. 13438

Prediction of clonogenic cell survival curves based on the number of residual DNA double strand breaks measured by γH2AX staining
Menegakis‌, A.; Yaromina‌, A.; Eicheler‌, W.; Dörfler, A.; Beuthien-Baumann, B.; Thames, Howard D.; Baumann‌, M.; Krause, M.
Abstract: Purpose:
To assess the potential of using the residual phosphorylation of histone H2AX (γH2AX) after irradiation as a marker of radiosensitivity invitro.

Material and methods:
Confluent cell cultures of FaDu and SKX human squamous cell carcinoma lines were irradiated with graded single doses. Twenty-four hours after irradiation cells were seeded for standard colony forming assay (CFA). In parallel, staining for γH2AX was performed to visualise the residual foci.

Results:
In the CFA, FaDu showed a higher radioresistance than SKX. After analysis of the residual foci data, we constructed ‘predicted’ survival curves using two different methods. First, the proportion of nuclei with <3 foci was found to correlate closely with the observed surviving fraction (SF) in FaDu, with a slight overestimation of the true SF in SKX. Second, there was a strong linear correlation of the mean number of residual foci and observed −lnSF. Based on regression analysis, we calculated the SF for both cell lines based on the mean number of residual γH2AX foci. This second approach again led to a good correlation of predicted and observed SF values in FaDu and a (slight) overestimation in SKX.

Conclusion:In the two cell lines investigated the mean number of residual foci of γH2AX can be used to predict differences in the radiation dose response relationship invitro.

International Journal of Radiation Biology 85(2009)11, 1032-1041

Registration 25.11.2009 11:30, No. 13437

PET-Tracer für die onkologische Diagnostik: Welche radiomarkierten Substanzen sind relevant?
Knieß, T.; Steinbach, J.
Abstract: Krebserkrankungen entstehen aus Veränderungen in den Wechselwirkungen zwischen Onkogenen und Tumorsupressorganen, welche unter normalen physiologischen Bedingungen für die Regulierung des Zellwachstums und der Zellteilung verantwortlich sind. Das Verhalten der Krebszelle wird dabei durch eine Vielzahl von Faktoren aus dem genetischen und Mikormilieu des Organismus bestimmt. Als Ergebnis der genetischen Abweichungen treten bestimmte funktionale Veränderungen auf. So sind Tumorzellen durch erhöhten Stoffwechsel (Glukosemetabulismus, Aminosäuretransport, Protein-, DNA- und Lipidsynthese) sowie durch angiogene und hypoxische Prozesse charakterisiert, welche unweigerlich zu der Ausbildung von unkontrollierten Läsionen führen.

Der vorliegende Artikel gibt einen kurzen Überblick über die zur Zeit in der Klinik verwendeten mit den Radionukliden ¹⁸F und ¹¹C markierten PET Radiotracer für die onkologische Diagnostik und beschreibt kurz ihre Herstellung und das Prinzip ihrer spezifischen Anreicherung.

Onkologische Pharmazie 11(2009)4, 4-5

Registration 19.11.2009 15:43, No. 13413

Motion Compensation in Positron Emission Tomography: Performance of a Clinical Integration at the PET centre Dresden-Rossendorf
Langner, J.
Abstract: Positron emission tomography (PET) is a well-established functional imaging method used in nuclear medicine. It allows for retrieving information about biochemical and physiological processes in vivo. The currently achievable spatial resolution of PET is about 5mm for brain acquisitions and about 8mm for whole-body acquisitions. However, recent improvements in image reconstruction methods point to a resolution of 2mm in the near future. Typical acquisition times range from minutes to hours due to the low signal-to-noise ratio of the measuring principle of PET, as well as due to the monitoring of the metabolism of the patient over a certain time. Therefore, patient motion increasingly limits the possible spatial resolution of PET. In addition, patient immobilizations are only of limited benefit in this context. Thus, if kept uncorrected, patient motion leads to a relevant resolution degradation and incorrect quantification of metabolic parameters.
In this talk, the results of a novel motion compensation method for clinical brain PET acquisitions developed at the research centre Dresden-Rossendorf (Forschungszentrum Dresden-Rossendorf ) in cooperation with the nuclear medicine department of the university hospital of the Technical University Dresden are presented. By using an external motion tracking system, information about the head motion of a patient is continuously acquired during routine PET acquisitions. Based on the motion information, an event-based motion compensation algorithm performs spatial transformations of all registered coincidence events, thus utilizing the raw data of a PET system - the so-called list-mode data. For routine acquisition of this raw data, methods have been developed which allow for the first time to acquire list-mode data from an ECAT Exact HR⁺ PET scanner within an acceptable time frame. Furthermore, methods for acquiring the patient motion in clinical routine and methods for an automatic analysis of the registered motion have been developed. For the clinical integration of the aforementioned motion compensation approach, the development of additional methods (e.g. graphical user interfaces) was also part of this work.
After development, optimisation and integration of the event-based motion compensation in clinical use, analysis with example data sets have been performed. Noticeable changes could be demonstrated by analysis of the qualitative and quantitative effects after the motion compensation. From a qualitative point of view, image artefacts have been eliminated, while quantitatively, the results of a tracer kinetics analysis of a FDOPA acquisition showed relevant changes in the R0k3 rates of an irreversible reference tissue two-compartment model. Thus, it could be shown that an integration of an event-based motion compensation method which is based on the utilization of the raw data of a PET scanner, as well as the use of an external motion tracking system, is not only reasonable and possible for clinical use, but also shows relevant qualitative and quantitative improvements for PET imaging.

Invited lecture (Conferences):
Columbia Kreitchman PET Center, 10.11.2009, New York, USA

Registration 13.11.2009 11:30, No. 13377

First evaluation of a fast full 3D list-mode based image reconstruction for PET
Lougovski, A.; Mölle, H.; Langner, J.; Will, E.; van den Hoff, J.
Abstract: Ziel/Aim:
Despite the fact that all modern PET scanners support 3D data acquisition protocols, up to now only a few of them have supported full 3D image reconstruction. Normally the reconstruction task is performed in sinogram space and reduced to a 2D problem using Fourier rebinning. This implies certain approximations and can degrade image quality. 3D list-mode reconstruction potentially is able to overcome these limitations while allowing at the same time flexible integration of motion correction methods into the reconstruction. The very limited availability of corresponding open-sourced software motivated us to develop our own, platform independent, fully 3D list-mode reconstruction with the final goal of integration of our event-based motion correction into it.

Methodik/Methods:
As the basis for our reconstruction we have taken the Ordinary Poisson List-mode Ordered Subsets Expectation Maximization algorithm (OP-LMOSEM) with on-the-fly system matrix simulation using a ray-tracing technique. The source code (C++) supports multi-threading and allows distributed computing, both of which decreases reconstruction time considerably. It also includes all
necessary corrections (attenuation, normalization, randoms etc.). We use the Single Scatter Simulation algorithm to compensate for Compton scatter and have evaluated the new reconstruction by comparison with the standard OSEM-reconstruction available with our Siemens EXACT HR+ scanner. Phantom measurements were performed in list-mode using the software previously developed in our lab. The evaluation procedure has been divided into three parts: i) quantitative accuracy (ROI's mean value comparison); ii) spatial resolution (FWHM comparison); iii) Signal to Noise Ratio, SNR (ratio of standard deviation to mean value in homogeneous ROIs).

Ergebnisse/Results:
Relative to the standard reconstruction we obtain the following results: quantitatively, images show reasonable concordance with the reference, abstract-dialog | Abstract Management System
the differences are below 8%. The reconstructed spatial resolution is on average 10% better (up to 20% in smaller structures). The mean SNR shows 6% improvement (especially at the axial edges of the field of view). Currently, reconstruction time for a typical 5 minute FDG brain scan is 13 minutes using 64 cores running at 2.3 GHz.

Schlussfolgerungen/Conclusions:
3D list-mode reconstructions are approaching clinical usefulness and prospectively offer the optimal framework for incorporating event-based motion correction methods into the reconstruction. Our implementation has proven to provide results, which already are better then those of the standard reconstruction on our system, although there is still room for much improvement. In the next step we plan to incorporate motion correction into the algorithm.

Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A26
Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D

Registration 09.11.2009 14:42, No. 13362

Blood flow measurements using MRI and Arterial Spin Labeling: a comparison with radioactive microspheres
Bos, A.; Bergmann, R.; Strobel, K.; van den Hoff, J.
Abstract: Aim:
Arterial Spin Labeling (ASL) is a Magnetic Resonance Imaging (MRI) technique for quantitative blood flow measurements. While the principal validity of the technique has been shown, e.g. for human brain investigations, its practical applicability and accuracy depends very sensitively on the specific experimental setting. The purpose of this work was the evaluation of ASL for perfusion measurements in the rat brain by a comparison with microsphere derived regional perfusion information using dedicated small animal PET and SPECT systems.

Methods:
MRI measurements were performed first, immediately followed by the microsphere measurements. Before measurements, catheters were implanted through the right carotid artery into the left ventricle of the heart for administration of radio-labeled microspheres (20). The in-vivo distribution of radio-labeled microspheres was evaluated by PET (microPET P4, Siemens) using Cu-64 and Ga-68 microspheres. For SPECT (NanoSPECT, Bioscan) measurements Tc-99m microspheres were used. MRI perfusion measurements were performed in a 7T small animal system (BioSpec 70/30, BRUKER) with the vendor provided ASL protocol using a FAIR (flow-sensitive alternating inversion recovery) sequence with an adiabatic hyperbolic secant inversion pulse (length-bandwidth product: 80). The global and selective T1 images were used for calculation of perfusion values.

Results:
For normal rat brain (without catheter) we measured perfusion values using FAIR-ASL ranging from 1.2 to 1.4 ml/min/g in the caudate putamen. The implantation of the catheter created differences in the perfusion between the right and left hemisphere of the brain (due to the partial blocking of the right carotid artery), which are apparent from the left/right differences in the microsphere distribution. These differences are visible in the ASL-derived perfusion as well, ranging from 25 - 60%. ASL-derived perfusion exhibits substantial inter- and intra-individual variability, the cause of which is currently under investigation.

Conclusions:
Quantitative perfusion measurements in the rat brain using ASL seem possible but are very susceptible to minor deviations from the optimal setup (e.g. concerning shimming of the magnetic field and motion artifacts). Overall regional contrast is on average concordant with regional distribution of microspheres. In order to be useful for routine application in small animal imaging, ASL data acquisition and data evaluation needs to be further optimized. A final calibration via a quantitative comparison with radio-labeled microspheres seems mandatory.

Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A27
Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D

Registration 09.11.2009 14:33, No. 13361

Kann die Atembewegungskorrektur die Darstellung und Quantifizierung im Abdomenbereich verbessern?
Mölle, H.; Langner, J.; Beuthien-Baumann, B.; Oehme, L.; Hofheinz, F.; Kotzerke, J.; van den Hoff, J.
Abstract: Ziel/Aim:
Vor dem Hintergrund einer kontinuierlichen Verbesserung der apparativ erreichbaren räumlichen Auflösung in der PET stellen Patientenbewegungen einen maßgeblichen Faktor dar, der die praktisch realisierbare räumliche Auflösung beschränkt. Bei PET-Aufnahmen vom Thorax und Abdomen kommt es insbesondere durch die unvermeidbare Atembewegung des Patienten zur zyklischen Verschiebung der inneren Organe sowie anderer Zielstrukturen. Hieraus resultiert eine unter Umständen beträchtliche Bewegungsunschärfe in den tomographischen Bilddaten. Dies erschwert die visuelle Beurteilung und führt zu Fehlern bei der Bestimmung quantitativer Parameter wie der maximalen Traceranreicherung und dem Volumen der Strukturen. Besonders betroffen hiervon sind kleine Strukturen wie etwa die Nierenkelche. So war es Ziel dieser Arbeit, die Quantifizierung und die Erkennbarkeit von kleinen Strukturen im Abdomen zu verbessern.

Methodik/Methods:
Bei 40 Patienten wurde eine Ganzkörperuntersuchung mit F18-FDG am PET-Scanner ECAT Exact HR+ durchgeführt. Gleichzeitig erfassten Infrarot-Tracking-Kameras die Atembewegung der Patienten. Anschließend wurde eine Atemtriggerung anhand der Atembewegungsamplitude durchgeführt. Die Bewegung der Nieren wurde durch die Differenz der Nierenpositionen in der end-exspiratorischen und der end-inspiratorischen Atemphase bestimmt. Die Korrektur der Nierenbewegung erfolgte mit Hilfe einer rigiden Transformation, die alle Atemphasen auf eine gemeinsame Atemphase abbildet.

Ergebnisse/Results:
Von 40 F18-FDG Patienten konnte bei 26 die Bewegung der linken und bei 24 die Bewegung der rechten Niere ermittelt werden. Bei den übrigen Patienten war die F18-FDG-Anreicherung in den Nieren zu gering, um die Bewegung zu bestimmen. Die mittlere kraniokaudale Bewegung der linken Niere betrug 8,6 mm und die der rechten Niere 8,2 mm. Es wurde ein Vergleich des maximalen SUV und des Volumens einer lokalen Traceranreicherung in der Niere zwischen dem bewegungskorrigierten und dem unkorrigierten PET-Bild durchgeführt. Bei den Patienten zeigte sich eine maximale Reduktion des Volumens um 40% und eine maximale Zunahme des SUV um 20%.

Schlussfolgerungen/Conclusions:
Die Atembewegung beeinflusst maßgeblich die Darstellung und Quantifizierung im Abdomenbereich. Für eine verlässliche Quantifizierung ist eine Korrektur der Bewegung im Abdomen notwendig.

Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A28
Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D

Registration 09.11.2009 14:22, No. 13359

Einfluss der event-basierten Bewegungskorrektur auf die Bestimmung pharmakokinetischer Parameter bei PET-Hirnuntersuchungen
Langner, J.; Mölle, H.; Oehme, L.; Hofheinz, F.; Beuthien-Baumann, B.; van den Hoff, J.
Abstract: Ziel/Aim:
Patientenbewegungen sind in der PET unvermeidbar. So können hierdurch die Bilddaten z.B. verfälscht oder bei dynamischen Hirnuntersuchungen die Bestimmung von Zeit-Aktivitäts-Kurven (TAC) bzw. die Quantifizierung pharmakokinetischer Parameter beeinflusst werden. Die in diesem Zusammenhang in den letzten Jahren entwickelten Methoden zur Registrierung und Korrektur der Patientenbewegung stellen nützliche Werkzeuge zur Minimierung dieser Effekte zur Verfügung. In der vorliegenden Arbeit war es Ziel, den Einfluss einer bereits routinemäßig an unserer Einrichtung angewandten event-basierten Bewegungskorrektur, die auf der räumlichen Transformation jeder Line-of-Response (LOR) basiert, innerhalb eines größeren Patientenkollektivs zu untersuchen. Hierdurch sollten Aussagen darüber getroffen werden, in welchem Maße die Korrekturmethode in der Lage ist, den Einfluss der Bewegung auf die Auswertung von dynamischen Hirnuntersuchungen zu reduzieren.

Methodik/Methods:
Bei 645 [¹⁸F]DOPA-Untersuchungen mit Fragestellung Morbus Parkinson wurde eine Bewegungskorrektur durchgeführt. Hierbei wurde bei 20% eine maximale Bewegung größer 7 mm festgestellt. Für diese Untersuchungen wurden die Einstromraten (R₀k₃) mittels eines irreversiblen Zweikompartment-Modells mit Referenzgewebe (Patlak-Auswertung) sowohl vor als auch nach Bewegungskorrektur bestimmt. Hierfür wurden 8 ROIs innerhalb des Striatum sowie eine ROI im Referenzgewebe positioniert und für jede ROI im Striatum die Zeit-Aktivitäts-Kurve (TAC) sowie die Einstromrate berechnet. Des Weiteren wurden für jeden Datensatz parametrische Bilder erzeugt und mit den unkorrigierten Daten verglichen.

Ergebnisse/Results:
Die maximale Bewegung in den insgesamt 645 Untersuchungen verteilt sich wie folgt: (i) 31%: 0,5 – 3 mm, (ii) 31%: 3 – 5 mm, (iii) 18%: 5 – 7 mm, (iv) 20%: > 7 mm. Bei der quantitativen Auswertung zeigten sich Unterschiede im Verlauf der TAC von bis zu 30-40%. Die R₀k₃ Werte zeigten zum Teil Änderungen von mehreren hundert Prozent. Im Vergleich der parametrischen Bilder konnte dies verifiziert werden.

Schlussfolgerungen/Conclusions:
Die Quantifizierung tracerkinetischer Parameter wird von Patientenbewegungen, deren Ausmaß vergleichbar mit der Größe der Zielstrukturen ist, empfindlich beeinflusst und verliert u.U. ihre Gültigkeit. Eine event-basierte Bewegungskorrektur ist in der Lage, diese Fehlerquelle zu minimieren.

Conference abstract in ref. journal:
Nuklearmedizin 49(2010)2, A36
Lecture (Conference):
48. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin (DGN), 21.-24.04.2010, Leipzig, D

Registration 09.11.2009 14:10, No. 13358

Synthesis of new bifunctional chelators for conjugation to vector molecules for tumor targeting.
Heldt, J.-M.; Ruffani, A.; Zenker, M.; Walther, M.; Stephan, H.; Pietzsch, H.-J.; Steinbach, J.
Abstract: Problem:
The goal of this study is to prepare novel chelators suitable for conjugation to vector molecules which can be labeled by yttrium or copper in order to achieve high specific activities and to improve pharmacokinetics. In this context, new water soluble bifunctional DOTA- and bis(2-pyridylmethyl)triazacyclocyclononane (DMPTACN)-based chelators have been synthesized and conjugated to the monoclonal antibody Cetuximab which binds to HER2 of the epithelial growth factor receptor (EGFR) family which is over-expressed by various tumors.

Material and Method:
Both chelators have been conjugated to Cetuximab via thiourea-bridging. Radiolabeling of DOTA derivatives has been performed in aqueous ammonium acetate solution at r.t. using ⁸⁶YCl₃ or ⁹⁰YCl₃. Radiolabeling of DMPTACN conjugates with ⁶⁴Cu was achieved in MES buffer solution at 50°C using ⁶⁴CuCl₂. The affinity of the bioconjugates towards EGFR was determined by ELISA.

Results:
The ELISA test showed that the affinity of the bioconjugates has decreased compared to native Cetuximab. A chelator/antibody molar ratio of 4 was achieved as determined by MALDI-TOF-MS for the DOTA-Cetuximab conjugate. Radiolabeling of DOTA-conjugates with ⁸⁶Y and ⁹⁰Y at 37°C requires optimization to improve radiochemical yield. DMPTACN-Cetuximab conjugates can be rapidly labeled with ⁶⁴Cu under mild conditions in almost quantitative yield.

Conclusions:
DMPTACN- and DOTA-ligands are attractive bifunctional chelating agents which can be conjugated to vector molecules for PET-imaging and radiotherapy. In the near future, the work with the ligands investigated will be extended using the pre-labeling approach.

Lecture (Conference):
Targeting and Imaging of the Tumor Microenvironment, 23.-26.09.2009, Berder island, France

Registration 21.10.2009 10:56, No. 13283

Structure-activity relationship of radiocopper-labeled DMPTACN-Bombesin conjugates
Ruffani, A.; Stephan, H.; Bergmann, R.; Steinbach, J.; Gasser, G.; Spiccia, L.
Abstract: Aim:
Radiometal‐labeled peptide derivatives of bombesin are very interesting targeting vectors for certain types of cancer. Bombesin derivatives have shown very high selectivity and affinity to
G‐protein‐coupled gastrin‐releasing‐peptide‐receptor (GRPR), which is over‐expressed in a variety of tumors including breast‐, prostate‐ and pancreatic‐tumors. Consequently, the
application of radiolabeled bombesin‐analogs for both the diagnosis and therapy of such tumors is being intensively investigated. However, the development of chemically and radiolytically
stable compounds which can be easily radiolabeled presents significant challenges. We recently showed that bis(2‐pyridylmethyl)triazacyclocyclononane (DMPTACN) was a promising candidate
for radiocopper‐labeling. In this study we examine structure‐activity relationships for new [64Cu]DMPTACN bombesin derivatives including their biodistribution and pharmacokinetics in
prostate cancer (PC3) xenografted tumor mice.

Methods:
Stabilized bombesin derivatives β‐Ala‐β‐Ala‐[Cha13,Nle14]BBN(7‐14) and β‐homo‐Glu‐β‐Ala‐β‐Ala‐[Cha13, Nle14]BBN(7‐14) were conjugated to the N‐terminus with DMPTACN ligands containing either a carboxylate or phenylisothiocyanate pendant arm via amide coupling and thiourea‐bridging, respectively. Radiolabeling of DMPTACN‐BBN derivatives with 64Cu was performed in aqueous ammonium acetate solution (pH=6) at 50°C using [64Cu]CuCl2. The affinity of DMPTACN‐BBN derivatives for the GRPR was determined using a competitive displacement/binding assay in human prostate (PC3) cancer cells. Internalization data for the [64Cu]Cu‐DMPTACN bombesin derivatives were obtained in the same cell line. Partition coefficients of the radiocopper‐labeled complexes of the DMPTACN‐BBN derivatives were determined in a 1‐octanol/buffer system. Biodistribution studies were performed on Wistar rats and NMRI nu/nu mice bearing the human prostate tumor PC‐3. Tumor accumulation was evaluated with small animal PET.

Results:
Radiolabeling of DMPTACNBBN‐bioconjugates was achieved in 30 min, yielding >99% radiochemical purity and specific activity up to 30 GBq/μmol after HPLC. DMPTACN‐NCS derivatives could be rapidly labeled with 64Cu under mild conditions in almost quantitative yield. The DMPTACN‐BBN conjugates showed high affinity to the GRPR and high uptake in PC‐3 cells. PET studies on tumor‐bearing PC‐3 mice revealed an accumulation in the GRPR‐positive tissue. Clear visualization of the tumor tissue and noticeable delineation from healthy tissue was achieved.

Conclusion:
DMPTACN ligands are attractive chelates for the development of radiocopper pharmaceuticals featuring very high chemical and radiolytical stability. They can be effectively coupled to target‐oriented peptides, such as bombesin. However, many issues need to be resolved, including the metabolic stabilization of the peptides and the direct fixation of radiometalated conjugates in the tumor tissue. DMPTACN‐isothiocyanate was found to be rapidly and efficiently labeled with 64Cu. These features make it a promising candidate as a pre‐labeling building block for antibody and synthetic polymers.

Lecture (Conference):
Annual Congress of the European Association of Nuclear Medicine (EANM´09), 10.-14.10.2009, Barcelona, Spain
Conference abstract in ref. journal:
European Journal of Nuclear Medicine and Molecular Imaging 36(2009)Suppl. 2, S207

Registration 21.10.2009 10:23, No. 13282

Synthesis and Metabolic Stability of ¹¹C-Labelled SU11248 Derivative as Inhibitor of Tyrosine Kinases
Knieß, T.; Bergmann, R.; Steinbach, J.
Abstract: Aim:
SU11248 is a novel inhibitor of receptor tyrosine kinases (RTKs) targeting vascular endothelial growth factor (VEGF) and plated‐derived growth factor (PDGF) [1]. Due to the fact that RTKs are overexpressed in some tumour entities, they might be a suitable target for cancer imaging by positron emission tomography (PET). A tyrosine kinase inhibitor labelled with a positron emitting isotope could represent a useful tool for monitoring levels of RTKs in tumour tissue by giving valuable information for anti‐angiogenic therapy. For this purpose we synthesized a methoxy substituted derivative of SU11248 and performed the radiosynthesis with the PET radionuclide carbon‐11 to the corresponding ¹¹C‐labelled radiotracer. First investigations on the in vivo metabolic stability of the new ¹¹C‐labelled SU11248 derivative are reported.

Materials and methods:
The radiolabelling was performed via ¹¹C‐methylation reaction of the corresponding desmethyl precursor with [¹¹C]MeI in a TRACERLab FX_C gas phase synthesizer (GE). After purification by semi‐preparative HPLC and solid phase extraction the radiotracer was dispensed with E153 electrolyte solution and injected intravenously into male Wistar rats. For metabolite analysis blood samples were taken from the arteria femoralis at 1.5; 3; 5; 10, 20, 30 and 60 minutes past injection. After centrifuging blood samples 5 min 13.000 rpm at 4°C plasma was analyzed by radio HPLC.

Results:
The synthesis of the non‐radioactive methoxy‐substituted SU11248 as well as the desmethyl precursor was accomplished by reacting 5‐methoxy‐ and 5‐hydroxyl‐oxindole with 5‐formyl‐2,4‐dimethyl‐1H‐pyrrole‐3‐carboxylic‐acid‐(2‐diethylaminoethyl)‐amide. Radiolabelling was achieved by reaction of the 5‐hydroxy‐substituted SU11248 derivative with [¹¹C]CH₃I in DMF/aqueous NaOH at 80°C. After semi‐preparative HPLC purification the ¹¹C‐labelled radiotracer was obtained in 14‐17% decay corrected radiochemical yield at a specific activity of 162‐198 GBq/μmol at the end of synthesis in 94‐99% radiochemical purity. Metabolism analysis in rat plasma showed 96% of intact compound 3 min and 73% 60 min p.i., together with three more polar metabolites.

Conclusion:
The new ¹¹C‐labelled derivative of SU11248 can be synthesized in good radiochemical yield, sufficient purity and high specific activity. The found metabolic stability in rat plasma showing 73% of intact radiotracer 60 min p.i. suggests that the ¹¹C‐methoxy labelling group is preserved under in vivo conditions. These findings are encouraging for further investigation with this radiotracer on RTK expressing cells and tumour tissue to answer the question if this radiotracer would be a useful tool for monitoring angiogenic processes by PET. [1] Sun L., Liang C. et al., J. Med. Chem., 46, (2003), 1116

Poster:
Annual Congress of the European Association of Nuclear Medicine (EANM), 10.-14.10.2009, Barcelona, Spain
Conference abstract in ref. journal:
European Journal of Nuclear Medicine and Molecular Imaging 36(2009)Suppl. 2, S310-S311

Registration 21.10.2009 09:22, No. 13281

Side Effects on the Heart and Skeleton of Growing Mice Attributed to Chronic Imatinib Exposure
Suttorp, M.; Boehme, J.; Vaitl, J.; Mosch, B.; Pursche, S.; Jung, R.; Bergmann, R.; Fischer, R.; Pietzsch, J.; Bornhaeuser, M.; Gasser, Jürg A.
Abstract: Objectives: Chronic myeloid leukemia (CML) is effectively treated by Imatinib (IM) via inhibition of the BCR-ABL tyrosine kinase. However, also related tyrosine kinases like abl, c-Kit, PDGF-R, and c-FMS are blocked by IM. As shown in adult humans and mice, abl-controlled protein folding as part of the endoplasmatic stress response in heart myoblasts as well as bone "remodeling" depending on PDGF-R and c-FMS is impaired under imatinib exposure (Dewar AL et al 2005, Kerkelä R et al 2006, Fitter S et al 2008). The influence of IM on the growing heart and skeleton of immature animals has not been studied so far. With respect to treatment of pediatric CML we report alterations in these organs of juvenile mice chronically exposed to IM during the growth period.
Methods: From the age of 4–14 weeks (w) [development milestones of mice: weaning 3 w; puberty 7 w; epiphysial lines closure 18 w] C3H/Neu male and female wild-type mice were chronically exposed to IM via the drinking water at concentrations of 500 mg/l (group A), 750 mg/l (group B), and 1000mg/l (group C). Femur length and overall skeletal development was analysed by whole body X-ray analysis using a mammography device. Bone metabolic activity was assessed by total body Na18F PET and CT after 5w and 10w of exposure using dedicated small animal tomographs. Bone mineral density and microstructure of tibiae were analysed by pQCT and microCT (resolution 12.5µ m) while the number of osteoclasts and resorption lacunae in femora and vertebrae was assessed by histomorphometry. Plasma concentration of IM, osteocalcin, and activity of the tartrate resistant acid phosphatase (TRAP5b) was also determined. The heart was examined histologically and ultrastructurally by electron microscopy.
Results: IM was tolerated well and mean uptake of 80 mg/kg/d
A. 110 mg/kg/d
B. and 150 mg/kg/d
C. resulted in serum levels of 60–674 ng/ml, 36–242 ng/ml and 51–534 ng/ml, respectively.
Body weight gain was delayed in groups B and C until the age of 8 w while no change in overall growth, development and behaviour was observed at 14 w. At higher doses of IM and at younger age there was a non-significant trend to a reduction in femur length. Heart morphological examination exhibited an increased number (p<0.05) of hypertrophic cardiomyocytes (toxic damage) paralleled by ultrastructural alterations in mitochondria, myofibrils, and nucleus. In the skeleton, no significant differences compared to controls concerning 18F-kinetics and uptake in vertebrae and femura could be demonstrated. However, IM dose-dependently reduced the number of osteoclasts and resorption lacunae (p<0.05); these effects were less pronounced in female mice. Tibia cortical thickness was increased significantly in males by 6.1% (B) and 11.2% (C), respectively, and 7.5% in females (C). By microCT cancellous bone exhibited a significant increase in trabecular bone mass density and volume and number resulting in an increase in trabecular connectivity in males by 63% (B) and 64% (C), respectively, and in females by 22% (B) and 38% (C), respectively. Bone biomarkers indicated a significant reduction of TRAP5b activity while osteocalcin levels remained unchanged.
Conclusion: In juvenile mice, a chronic exposure of IM resulted in toxic damage of the cardiomyocytes at higher dose rates. However, these alterations do not necessarily imply also a functional impairment which can only be studied in vivo. In the skeleton, IM reduced the number of osteoclasts and resorption lacunae in long bones but not in vertebrae. IM showed an antiresorptive effect in cancellous bone and increased cortical thickness and trabecular number by inhibiting the expansion of the marrow cavity. The effects were more pronounced in male mice and at younger age.

Poster:
Annual Meeting American Society of Hematology, 06.-09.12.2008, San Francisco, USA
Conference abstract in ref. journal:
BLOOD 112(2008), 402

Registration 14.10.2009 15:20, No. 13254

NMR Studies and Crystal Structure Determinations of CF3 Group-containing Bicyclic phenolates
Mamat, C.; Reinke, H.; Langer, P.
Abstract: Three new CF3-substituted bicyclic Salicylate derivatives were synthesized by the TiCl4-mediated cyclization Of trifluoromethyl-containing ketones with 1,3-bis(silyl enol ethers) and characterized by NMR and IR, spectroscopy, Mass spectrometry and elemental analysis. The crystal structures of the bicyclic derivatives have been determined by single crystal X-ray analysis. All structures exhibit hydrogen bonding.

Zeitschrift fur Naturforschung Section B - A Journal of Chemical Sciences 64(2009)4, 423-426

Registration 14.10.2009 14:46, No. 13252

Radiokupfer-markierte Peptide auf der Basis neuer bifunktioneller Chelatliganden
Stephan, H.; Bergmann, R.; Steinbach, J.
Abstract: Die erfolgreiche klinische Anwendung von radioaktiv markierten Somatostatin-Peptid-Analogen für die Bildgebung von rezeptorexprimierenden Tumoren hat die Modifizierung anderer Regulatorpeptide wie Neurotensin, RGD-Peptide oder Bombesin als mögliche Tumordiagnostika und –therapeutika vorangetrieben.[1] Auf dem Weg zu diesen neuen radioaktiven Arzneimitteln sind eine Reihe unterschiedlicher Aufgaben zu lösen. Das betrifft insbesondere die Entwicklung von chemisch und radiolytisch stabilen Verbindungen, die eine unkomplizierte Markierung der Peptide mit geeigneten Radionukliden erlauben. ^99mTc-, ⁶⁴Cu- und ⁶⁸Ga-markierte Peptide eignen sich dabei prinzipiell zur Tumordiagnostik. Analoge Verbindungen mit den Partikelstrahlern ⁶⁷Cu und ¹⁸⁸Re weisen ein großes Potenzial zur Therapie von Tumoren auf. Zur stabilen Fixierung von radioaktiven Kupfernukliden sind beispielsweise Pyridin-haltige makrocyclische Amine I und Bispidin-Liganden II entwickelt worden, die gleichzeitig eine Konjugation von Peptiden erlauben. Auf der Basis stabilisierter Bombesinderivate konnten durch Anwendung geeigneter Peptidkupplungsreaktionen entsprechende Biokonjugate hergestellt werden. Diese Verbindungen bilden unter physiologischen Bedingungen mit schneller Kinetik sehr stabile Radiokupferkomplexe. Ligandenaustauschexperimente und radiopharmakologische in-vitro- und in-vivo-Untersuchungen belegen eine sehr hohe Komplexstabilität. Studien zur Bioverteilung eines Bombesinkonjugates mit I ergaben eine hohe Anreicherung im Pankreas, dem Zielorgan mit der höchsten Dichte am Gastrin Releasing Peptidrezeptor.[2] PET-Studien an PC3-Tumor-Mäusen unter Einsatz des ⁶⁴Cu markierten Bispidin-Bombesin-Derivates belegen eine gute Tumoranreicherung dieser Verbindung sowie eine klare Visualisierung des Tumors.[3]

Lecture (Conference):
GDCh-Wissenschaftsforum Chemie 2009, 30.08.-02.09.2009, Frankfurt/M., Deutschland

Registration 13.10.2009 14:46, No. 13249

Autoradiographic studies of rhenium-188-hydroxyethylidine diphosphonate in normal skeleton and osteoblastic bone metastases in a rat model of metastatic prostate cancer
Liepe, K.; Geidel, H. H.; Bergmann, R.; Haase, M.; Runge, R.; Kotzerke, J.
Abstract: Aim
The quantitative distribution of bone-seeking radiopharmaceuticals in trabecular bone, cortical bone and in skeletal metastases is required for calculation of radiation-absorbed dose in radionuclide therapy. An animal model of intraosseous tumor cell administration was developed to simulate osteoblastic metastases for autoradiographic study of radionuclide localization.
Methods In 45 Copenhagen rats R3327-MATLyLu syngeneic prostate cancer cells were given intraosseously in both the femori. Rhenium-188-hydroxyethylidine diphosphonate (HEDP) was administered intravenously 17 +/- 1 days after cells instillation and these animals were euthanized at 4, 24 and 48 h after injection of the radiopharmaceutical. The uptake of radiopharmaceutical was estimated in normal skeleton and the bone metastases by means of region of interest analysis using autoradiography. The tumor to nontumor ratio and the fractional uptake in cortical bone and trabecular bone were quantified.

Results
The uptake of rhenium-188-HEDP in cortical bone was 33.5% and in trabecular bones was 66.5% after 4 h, 34.6 and 65.4% after 24 h, and 35.9 and 64.1% after 48 h, respectively. Assuming a theoretic cortical-trabecular distribution of 50-50%, (MIRDOSE) calculation, radiation-absorbed dose to bone marrow was underestimated by 26%. In bone metastases, an inhomogeneous distribution with a minimal and maximal tumor to nontumor ratio of 3:1 and 14:1 after 4 h, 5: 1 and 14: 1 after 24 h, and 5:1 and 16:1 after 48 h was observed.

Conclusion
The MIRDOSE model underestimates the radiation-absorbed dose to the bone marrow because of demonstrable differences in the uptake of rhenium-188-HEDP in cortical and trabecular bone and inhomogeneous uptake in skeletal metastases.

Nuclear Medicine Communications 30(2009), 693-699

Registration 13.10.2009 14:35, No. 13248

Prätherapeutisches [¹⁸F]FMISO hypoxisches Volumen ist ein signifikanter prognostischer Faktor für die lokale Tumorkontrolle nach Einzeldosisbestrahlung von FaDu-Tumoren in Nacktmäusen/Pretherapeutic [F-18]FMISO hypoxic volume is a significant prognostic factor for local tumour control after single dose radiation of FaDu- tumours in night mouse
Schütze, C.; Bergmann, R.; Mosch, B.; Yaromina, A.; Zips, D.; Hessel, F.; Thames, H. D.; Mäding, P.; Kotzerke, J.; Baumann, M.; Beuthien-Baumann, B.
Abstract: Hintergrund:
Präklinische und klinische Untersuchungen haben gezeigt, dass das Ausmaß der prätherapeutischen Tumorhypoxie das Ergebnis einer Strahlentherapie solider Tumoren beeinflusst. Derzeit werden strahlentherapeutische Interventionen wie z.B. Dosis-Eskalation partieller hypoxischer Subvolumina untersucht. In dieser Studie wurde in einer einzelnen, in Nacktmäusen transplantierten humanen Tumorzelllinie untersucht, ob das prätherapeutische [¹⁸F]FMISO hypoxische Tumorvolumen (HV) oder die Intensität des Tracer-uptakes (maximaler Standard uptake
value SUV_max) mit der lokalen Tumorkontrolle nach Einzeldosisbestrahlung korreliert.

Methoden:
Die hSCC Zelllinie FaDu wurde subkutan auf das rechte Hinterbein von NMRI Nacktmäusen transplantiert. 70 Tiere wurden bei einem Tumorvolumen von 165-343 mm³ in das Experiment aufgenommen. Jedes Tier erhielt am Tag 0 eine PET-Untersuchung (MicroPET® P4, CTI Molecular Imaging Inc) mit dem Hypoxie-Marker ¹⁸F]FMISO ([¹⁸F]Fluormisonidazol) unter Anästhesie. Die Auswertung erfolgte mittels 3D-regions of interest über dem Tumor (ROVER software, ABX GmbH, Radeberg, Germany). Bestimmt wurde das [¹⁸F]FMISO hypoxische Volumen (HV) und der SUV_max. Anschließend wurden die Tumoren entsprechend des medianen hypoxischen Volumens für Einzeldosisbestrahlungen mit 25 Gy oder 35 Gy unter normalem Blutfluss randomisiert. Die Einzeldosisbestrahlungen erfolgten mit 200 kV Röntgenstrahlen (0.5 mm Cu, ~ 1 Gy min^-1). Der experimentelle Endpunkt war die lokale Tumorkontrolle am Tag 120 nach Bestrahlung.

Ergebnisse:
Die lokalen Tumorkontrollraten nach Bestrahlung mit 25 Gy waren niedriger als nach Bestrahlung mit 35 Gy (22% vs. 69%, Logrank-Test p< 0.0001). Die Spanne der HV reichte von 38-353 mm³, der Median HV betrug 112 mm³ (95%CI: 92; 128 mm³). Für Tumoren < Median HV betrug die lokale Kontrollrate 33% nach 25 Gy vs. 82% nach 35 Gy (p=0.001). In Tumoren > Median HV betrug die lokale Kontrollrate 15% nach 25 Gy vs. 53% nach 35 Gy (p=0.0005). In der multivariaten Cox-Analyse konnte nach Korrektur für Dosis und Tumorvolumeneffekte ein signifikanter Effekt des HV als kontinuierliche Variable (p=0.009) oder dichotome Variable (Stratifikation entsprechend des Median HV) (p=0.039) nachgewiesen werden. Der SUV_max war bezüglich der Prognose der Heilungswahrscheinlichkeit nicht relevant.

Schlussfolgerungen:
Das [¹⁸F]FMISO hypoxische Tumorvolumen ist ein signifikanter unabhängiger Prädiktor für das Ergebnis einer Bestrahlung mit hohen Einzeldosen in FaDu hSCC. Diese Ergebnisse unterstützen die Hypothese, dass ein prätherapeutisches [¹⁸F]FMISO-PET wichtige Informationen für die Verschreibung einer heterogenen Bestrahlungsdosis in
hypoxischen Subvolumina individueller Tumoren liefern kann. Weitere Experimente mit anderen Tumormodellen und fraktionierter Bestrahlung sind notwendig.

Gefördert im Rahmen des EU-Projektes „BioCare“ Molecular Imaging for Biologically Optimized Cancer Therapy proposal# 505785 und DFG Projekt Ba 1433.

Lecture (Conference):
DEGRO 2009 - 15. Jahreskongress der Deutschen Gesellschaft für Radioonkologie, 11.-14.06.2009, Bremen, Deutschland
Conference abstract in ref. journal:
Strahlentherapie und Onkologie 185(2009)Suppl. 1, 22-23

Registration 13.10.2009 14:03, No. 13247

In^III and Ga^III Complexes of Sugar-Substituted Tripodal Trisalicylidene Imines: The First ⁶⁸Ga-Labelled Sugar Derivative
Gottschaldt, M.; Bohlender, C.; Pospiech, A.; Görls, H.; Walther, M.; Müller, D.; Klette, I.; Baum, Richard P.; Schubert, Ulrich S.
Abstract: Gallium and indium complexes derived from salicylaldimines of 1,1,1-tris(aminomethyl)ethane (TAME) with pendantxylose, glucose and galactose units have been synthesised as model compounds for potential application as radiotracers. The formed neutral complexes have been characterised by NMR spectroscopy, elemental analysis, mass spectrometry and, in the case of the galactose-bearing In^III complex, by single-crystal X-ray structure analysis. Octahedral coordination was observed with the appearance of an equilibrium of - and -isomers at the metal centre. The glucose-appended ligand was radiolabelled with ⁶⁸Ga^III ions in up to 98 % yield depending on the prevailing pH value. The in vitro stability of the radioactive complex was examined by challenge experiments against apo-transferrin and blood plasma. Very high stability was observed; even after a period of 2 h, 90 % of the complex could still be detected.

European Journal of Inorganic Chemistry 28(2009), 4298-4307

Registration 13.10.2009 13:22, No. 13246

Circulating S100A12: a novel player in atherosclerosis?
Pietzsch, J.
Abstract: S100A12 is a member of the S100 family of EF-hand calcium-binding proteins. Besides calcium binding S100A12 also shows high affinity for zinc and copper ions. Extracellular S100A12 is predominantly secreted by granulocytes and monocytes and is part of the innate immune response.
S100A12 is markedly overexpressed in inflammatory compartments, and elevated serum levels of S100A12 are found in patients suffering from various inflammatory and metabolic disorders. In this regard, binding of copper by S100A12 is assumed to play a pathogenic role. In vitro experiments show that copper-bound S100A12 can function as a pro-oxidant agent by supporting both copper reduction and copper redox-cycling, respectively. As a consequence, copper-bound S100A12 enhances and accelerates oxidation of human low density lipoprotein lipids and apolipoproteins, respectively. Furthermore, copper-bound S100A12 stimulates proinflammatory activation of endothelial cells, granulocytes, and monocytes. These processes were substantially suppressed in the presence of redox-inert copper-chelating or radical-scavenging agents. Clinical examinations show significantly elevated plasma S100A12 levels in subjects with impaired glucose tolerance, newly-diagnosed diabetes mellitus Type 2, and acute rheumatoid arthritis (1.5 to 3-fold higher than in control subjects). In the patient groups, plasma S100A12 is strongly associated with plasma markers of both LDL oxidation and inflammation, and, additionally, with ultrasonically measured carotid atherosclerosis. It is suggested that oxidation processes mediated by copper-bound S100A12 are involved in accelerated atherogenesis in proinflammatory states.
Supported by Deutsche Forschungsgemeinschaft (Pi 304/1-1)

Invited lecture (Conferences):
11th International Congress on Amino Acids, Peptides and Proteins, 03.-07.08.2009, Wien, Österreich
Conference abstract in ref. journal:
Amino Acids 37(2009)Suppl. 1, S78

Registration 13.10.2009 12:56, No. 13245

Molecular imaging of the receptor for advanced glycation endproducts
Pietzsch, J.; Hoppmann, S.
Abstract: The receptor for advanced glycation endproducts (RAGE) is a member of the immunoglobulin superfamily and has been implicated in the pathogenesis of various disorders including inflammatory processes and cancerogenesis. However, data concerning the functional expression of RAGE in inflammatory compartments and other pathologies in vivo are scarce. We report a multi-radiotracer approach using radiolabeling of various RAGE ligands, including glycated low-density lipoproteins (glycLDL), glycated albumin (glycBSA), and S100 proteins (S100B and S100A12) with the positron emitter fluorine-18 (18F) and the application of 18F-labeled RAGE ligands in dynamic small animal positron emission tomography (PET) studies. Radiolabeling of proteins was performed by conjugation with N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) causing no adverse alterations of the biological functionality of the proteins in vitro. Biodistribution and metabolite studies in rodent normal, inflammatory, and tumor models revealed high stability for the 18F-RAGE ligands in vivo. The in vivo kinetics of 18F-RAGE ligands, with or without presence of specific ligands or inhibitors of RAGE and, additionally, various scavenger receptors, in rodent models was quantified by PET, and correlated well with the anatomical localization of RAGE, e.g., in lung, endothelium, inflammatory lesions, and tumors.
18F-radiolabeling of glycLDL, glycBSA, and S100 proteins and the use of small animal PET provide a potential approach to measure the functional expression of RAGE under normal and pathophysiological conditions in vivo.
Supported by Deutsche Forschungsgemeinschaft (Pi 304/1-1)

Invited lecture (Conferences):
11th International Congress on Amino Acids, Peptides and Proteins, 03.-07.08.2009, Wien, Österreich
Conference abstract in ref. journal:
Amino Acids 37(2009)Suppl. 1, S39

Registration 13.10.2009 12:52, No. 13244

Fluorine-18 radiolabeling of S100/calgranulins: potential probes for molecular imaging of receptor for advanced glycation endproducts
Hoppmann, S.; Haase, C.; Richter, S.; Strobel, K.; Steinbach, J.; Pietzsch, J.
Abstract: The interaction of S100/calgranulins, a multigenic family of Ca²⁺-modulated proteins, with the receptor for advanced glycation endproducts (RAGE) is hypothesized to be of high relevance in the pathogenesis of various diseases including cardiovascular diseases, inflammatory processes, and cancerogenesis. However, data concerning the role of circulating S100 proteins in these pathologies are scarce. Furthermore, it is currently not known whether RAGE is an universal S100 receptor. One reason for this is the shortage of suitable radiolabeling methods for direct assessment of the metabolic fate of circulating S100 proteins in vivo. We report a novel radiotracer approach using radiolabeling of recombinant human S100A1 with the positron emitter-fluorine-18 (¹⁸F) by conjugation with N-succinimidyl-4-[¹⁸F]fluorobenzoate ([¹⁸F]SFB) and the use of [¹⁸F]fluorobenzoylated S100A1 (¹⁸F-S100A1) in dynamic small animal positron emission tomography (PET) studies in rats. Human S100A1 was cloned as a fusion protein in the bacterial expression vector pGEX-6P-1 and expressed in E. coli strain BL21. Radiolabeling of S100A1 with [¹⁸F]SFB at pH 7.4 resulted in ¹⁸F-S100A1 specifically labeled at the N-terminal glycine residue with radiochemical yields of 2-6% (decay-corrected) and effective specific activities of 0.5-1 GBq/µmol, respectively. In vitro experiments, and biodistribution and metabolite studies in rats in vivo revealed high stability for the ¹⁸F-S100A1. The metabolic fate of ¹⁸F-S100A1 in rats in vivo was delineated by dynamic PET studies using a dedicated small animal PET system. The organ-specific in vivo distribution and kinetics of ¹⁸F-S100A1 correlated well with the anatomical localization of RAGE, e.g., in lungs and in the vascular system. In the presence of molar excess of glycated human low density lipoprotein (glycLDL), a well characterized RAGE ligand, the mean plasma residence time of circulating ¹⁸F-S100A1 increased by 40% from 29.6 ± 1.5 min to 41.3 ± 2.1 min and, vice versa, tissue-associated retention of ¹⁸F-S100A1 decreased by approximately 50% in lungs and 32% in large blood vessels, respectively. These findings indicate first circulating S100A1 to be a specific ligand for RAGE in rats in vivo. In conclusion, radiolabeling of S100/calgranulins with ¹⁸F and the use of small animal PET provide novel probes to delineate functional expression of RAGE under normal and pathophysiological conditions in rodent models of disease in vivo.
Keywords: multiligand receptors; pattern recognition; S100 proteins; ¹⁸F-labeled prosthetic group; small animal positron emission tomography; animal models

Contribution to external collection:
Xiaoyuan Chen: Recent Advances of Bioconjugation Chemistry in Molecular Imaging, Kerala (India): Trivandrum: Research Signpost, 2008, 978-81-308-0210-7, 329-351

Registration 13.10.2009 12:40, No. 13243

Synthesis, ⁶⁴Cu-Labeling and Biodistribution of DOTA-Glycodendrimers
Jäger, K.; Stephan, H.; Bergmann, R.; Steinbach, J.; Appelhans, J.; Voit, D.
Abstract: The utilization of dendrimers in medicine holds great potential in emerging applications of diagnostic imaging, as well as the promise of new capabilities for delivering therapies tailored and targeted for specific diseases. In this perspective, radiolabeled dendritic frameworks are gaining in importance, particularly for the use in tumor imaging and therapy.[1] Pegylation as well as carbohydration of radiolabeled compounds is of considerable interest to improve the pharmacokinetics, biocompatibility, and tumor accumulation.[2,3]
In this context, DOTA-modified glycodendrimers with dense maltose shell (Figure: structure of 4th generation dendrimer) were selected from the point of view to use the highly homogenous dendritic structure for improved tumor imaging and therapy and to enhance the biocompatibility of dendrimers by the decoration with carbohydrates. The outcome of the synthetic effort was the synthesis of 4th and 5th generation glycodendrimers with the variation of chemically attached DOTA chelators (1, 3, 9 DOTA units/4th generation dendrimer; 9 and 18 DOTA units/5th generation dendrimer), which form stable complexes with a large number of radiometals. The multivalent decoration with DOTA on dendrimer surface was also stimulated by the facts that radiolabeling kinetics can be accelerated and to achieve enhanced specific activity.
The labeling conditions of the glycodendrimers synthesized with 64Cu were optimized, and the influence of reaction time, temperature, buffer conditions and the dendrimer amount on the radiochemical yield were studied using Radio-TLC and Radio-SEC. The radiocopper(II) complexes of the DOTA-functionalized glycodendrimers show a high in vitro stability. Preliminary biodistribution studies of ⁶⁴Cu-labeled 4th generation dendrimers with maltose shell in healthy Wistar rats indicate the preferred accumulation in the liver.

Poster:
GDCh-Wissenschaftsforum Chemie 2009, 30.08.-02.09.2009, Frankfurt am Main, Deutschland

Registration 13.10.2009 10:34, No. 13242

Visualizing inflammation activity in rheumatoid arthritis with Tc-99m Anti-CD4-mAb fragment scintigraphy - First results of a proof of principle study
Steinhoff, K.-G.; Pierer, M.; Sorger, D.; Seese, A.; Künstler, J. U.; Emmrich, F.; Sabri, O.; Hesse, W.; Siegert, J.; Piegla, U.; Pietzsch, H.-J.; Seidel, W.; Laub, R.
Abstract: T‐cell‐located CD4 antigen represents one of the therapeutic targets in rheumatoid arthritis (RA). However, up to now it has not been possible to visualize this target in vivo. The aim of our study was to assess the safety and tolerability of a Technetium 99 labelled anti‐CD4 antibody fragment (Tc‐99m‐anti‐CD4) in patients with active synovitis due to rheumatoid arthritis and to evaluate its potential as a marker of disease activity. Methods: In the present phase I proof of principle study 5 patients (3 female, 2 male, 58 to 71 years) with RA were examined. Planar whole body scans as well as separate hand and feet scintigraphies were taken 30 minutes, 1, 2, 4, 8 and 24 hours after application of 585 +/‐ 115 MBq Tc‐99m‐anti‐CD4. The obtained scintigramms were analysed visually and compared with clinical data in 68 joints per patient. Active inflammation was clinically defined by swelling and tenderness in at least one joint (gold standard). Patients were clinically re‐evaluated 7 days p.i. Results: Neither infusion related adverse events nor adverse events during follow up were observed. No increase in HAMA titres was seen. All 5 patients had positive scans in 25 of 37 clinically affected joints. Positive scans were also found in 19 out of 227 joints without evidence of swelling or tenderness yielding a 7% rate of false positive joints and a 32% rate of false negative joints. Conclusion: Scintigraphy with Tc‐99m‐anti‐CD4 is a new promising technique for evaluation of inflammatory activity in patients with RA. Tracer uptake in clinically inconspicuous joints strongly indicates diagnostic potential of 99Tc anti CD4. Based on the few patients investigated, it seems that inflammation is detected with apparently higher specificity than sensitivity. Whether this technique is eligible for prognostic disease evaluation needs to be analysed in further studies as well as the pathophysiological background of clinically affected joints lacking tracer uptake.

Lecture (Conference):
Annual Congress of the European Association of Nuclear Medicine 2009 (EANM), 10.-14.10.2009, Barcelona, Spain
Conference abstract in ref. journal:
European Journal of Nuclear Medicine and Molecular Imaging 36(2009)Suppl. 2, S210

Registration 13.10.2009 10:00, No. 13241

Synthesis and biological evaluation of new [Tc(N)(R₂PS)]-based mixed compounds as analogues of WAY 100635
Bolzati, C.; Cavazza-Ceccato, M.; Refosco, F.; Salvarese, N.; Pietzsch, H.-J.; Bergmann, R.; Bandoli, G.
Abstract: Aim: This study was focused on evaluating the applicability of a new labelling procedure to the preparation of Tc(N)‐based target specific compounds. The chemistry is based on the use of the [Tc(N)Cl(R2PS)(PPh3)] species (R2PS = alkyl‐phosphino‐thiolate ligand), which selectively reacts with an appropriate mono‐negative chelate, such as a dithiocarbamate (DTC), to give neutral [Tc(N)(R2PS)(DTC)] compounds. The 2‐methoxyphenylpiperazine (2‐MPP) pharmacophore, which displays a potent and specific affinity for 5HT1A receptors, was selected as functional group and conjugated to the dithiocarbamate unit through different spacers. Method: The synthesis of [99m/99gTc(N)(R2PS)(Ln)] complexes, and their in vitro stability as well as their biological in‐vitro and in‐vivo assays were investigated. Stability studies were performed by considering: i) stability toward transchelation with Cysteine and Glutatione ii) binding to the serum proteins; ii) stability in rat serum, human serum and rat liver homogenates. The in vitro affinity for the 5HT1A receptors of the technetium complexes was assessed by measuring the ability of the compounds to compete with [3H]‐8‐OH‐DPAT binding in isolated membranes from rat cerebral cortex. The biodistribution profile of the best radiolabeled compound and its in vivo stability were evaluated in Sprague‐Dawley rats. Results: [99mTc(N)(R2PS)(Ln)] complexes were prepared in high yield (>90%) using a multi‐step procedure. The chemical identity of 99mTc‐complexes was determined by HPLC comparison with the corresponding 99gTc‐complexes. All complexes were found to be inert toward transchelation with an excess of free Glutathione and Cysteine. No significant in vitro serum protein binding and no notable biotransformation of the native compound into different species by the in vitro action of the serum and liver enzymes were shown. Nanomolar affinities for the 5‐HT1A receptor were obtained for [99mTc(N)(PSiso)L3] (IC50 = 1.5 nM), a reduction of the affinity were observed for the other complexes as a function of the reduction of the alkyl chain length interposed between the DTC group and the bioactive molecule. A negligible brain uptake was displayed from in vivo distribution data of [99mTc(N)(PSiso)L3]. Conclusion This work describes the application of a new labelling procedure for incorporating a bioactive molecule into a stable dissymmetric 99mTc(N)‐complex. Despite the favourable binding properties, the lack of BBB penetration indicates that these particular complexes may not be useful for CNS‐receptor mapping. Further studies should be performed in order to clarify the reason for this behaviour and to evaluate the usefulness in peripheral applications.

Lecture (Conference):
Annual Congress of the European Association of Nuclear Medicine (EANM) 2009, 10.-14.10.2009, Barcelona, Spain
Conference abstract in ref. journal:
European Journal of Nuclear Medicine and Molecular Imaging 36(2009)Suppl. 2, S220

Registration 13.10.2009 09:37, No. 13240

Pages: [All] [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]


Bibliothek - 09.09.2010 Statistik