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Sample records for high-specific-activity 68ga-labeled dota-rhenium-cyclized

  1. (18)F- and (68)Ga-Labeled Neurotensin Peptides for PET Imaging of Neurotensin Receptor 1.

    PubMed

    Maschauer, Simone; Einsiedel, Jürgen; Hübner, Harald; Gmeiner, Peter; Prante, Olaf

    2016-07-14

    The neurotensin (NT) receptor-1 (NTS1) is overexpressed in a variety of carcinomas and is therefore an interesting target for imaging with positron emission tomography (PET). The aim of this study was the development of new NT derivatives based on the metabolically stable peptide sequence NLys-Lys-Pro-Tyr-Tle-Leu suitable for PET imaging. The NT peptides were synthesized by solid-phase supported peptide synthesis and elongated with respective chelators (NODA-GA, DOTA) for (68)Ga-labeling or propargylglycine for (18)F-labeling via copper-catalyzed azide-alkyne cycloaddition. Receptor affinities of the peptides for NTS1 were in the range of 19-110 nM. Biodistribution studies using HT29 tumor-bearing mice showed highest tumor uptake for [(68)Ga]6 and [(68)Ga]8 and specific binding in small-animal PET studies. The tumor uptake of (68)Ga-labeled peptides in vivo significantly correlated with the in vitro Ki values for NTS1. [(68)Ga]8 displayed an excellent tumor-to-background ratio and could therefore be considered as an appropriate molecular probe for NTS1 imaging by PET. PMID:27336295

  2. Tumor imaging with novel radiogallium (67/68Ga) labeled agents

    NASA Astrophysics Data System (ADS)

    Kulkarni, P. V.; Antich, P. P.; Constantinescu, A.; Ranney, D. F.; Fernando, J. L.; Xiong, R.; Oz, O.; Parkey, R. W.

    1997-02-01

    Gallium-67 (t1/2: 78 h) has played an important role in tumor imaging. It is produced in a cyclotron and is commercially available for routine clinical use. 68Ga (t1/2: 68 min), a positron emitter, suitable for positron emission tomographic (PET) imaging, is obtained from a generator with long lived parent 68Ge (t1/2: 288 d). Radiogallium has been used mostly, as gallium citrate in imaging studies. Recently, receptor specific agents labeled with gallium have been developed. These include, agents to image somatostatin and folate receptors. We have shown that a new class of agents based on glycosaminoglycoans (GLYCOS) target a variety of tumors. Gallium labeled deferroxamine (DF) bound to sulfated glycosaminoglycans has the ability to rapidly target and permeate a wide variety of solid animal tumors and also undergo rapid blood clearance almost exclusively by the renal route. We have been able to image (within 5 min to 1 hr), prostate adenocarcinoma (AT-1 tumor) grown in surgically prepared pedicles of Copenhagen male rats and breast tumor in pedicles of Fisher female rats. 67Ga labeled agent was used in single photon imaging mode and 68Ga labeled agent was used in PET mode with a small animal PET imaging device built in our laboratory with plastic scintillating optical fibers.

  3. (68) Ga-labeled Ciprofloxacin Conjugates as Radiotracers for Targeting Bacterial Infection.

    PubMed

    Satpati, Drishty; Arjun, Chanda; Krishnamohan, Repaka; Samuel, Grace; Banerjee, Sharmila

    2016-05-01

    With an aim of developing a bacteria-specific molecular imaging agent, ciprofloxacin has been modified with a propylamine spacer and linked to two common bifunctional chelators, p-SCN-Bz-DOTA and p-SCN-Bz-NOTA. The two ciprofloxacin conjugates, CP-PA-SCN-Bz-DOTA (1) and CP-PA-SCN-Bz-NOTA (2), were radiolabeled with (68)Ga in >90% radiochemical yield and were moderately stable in vitro for 4 h. The efficacy of (68)Ga-1 and (68)Ga-2 has been investigated in vitro in Staphylococcus aureus cells where bacterial binding of the radiotracers (0.9-1.0% for (68)Ga-1 and 1.6-2.3% for (68)Ga-2) could not be blocked in the presence of excess amount of unlabeled ciprofloxacin. However, uptake of radiotracers in live bacterial cells was significantly higher (p < 0.01) than that in non-viable bacterial cells. Bacterial infection targeting efficacy of (68)Ga-1 and (68)Ga-2 was tested in vivo in rats where the infected muscle-to-inflamed muscle ((68)Ga-1: 2 ± 0.2, (68)Ga-2: 3 ± 0.5) and infected muscle-to-normal muscle ratios ((68)Ga-1: 3 ± 0.4, (68)Ga-2: 6.6 ± 0.8) were found to improve at 120 min p.i. Fast blood clearance and renal excretion was observed for both the radiotracers. The two (68)Ga-labeled infection targeting radiotracers could discriminate between bacterial infection and inflammation in vivo and are worthy of further detailed investigation as infection imaging agents at the clinical level. PMID:26647765

  4. Synthesis and biological evaluation of (68) Ga-labeled Pteroyl-Lys conjugates for folate receptor-targeted tumor imaging.

    PubMed

    Zhang, Xuran; Yu, Qian; He, Yingfang; Zhang, Chun; Zhu, Hua; Yang, Zhi; Lu, Jie

    2016-07-01

    In order to develop novel (68) Ga-labeled PET tracers for folate receptor imaging, two DOTA-conjugated Pteroyl-Lys derivatives, Pteroyl-Lys-DOTA and Pteroyl-Lys-DAV-DOTA, were designed, synthesized and radiolabeled with (68) Ga. Biological evaluations of the two radiotracers were performed with FR-positive KB cell line and athymic nude mice bearing KB tumors. Both (68) Ga-DOTA-Lys-Pteroyl and (68) Ga-DOTA-DAV-Lys-Pteroyl exhibited receptor specific binding in KB cells in vitro. The tumor uptake values of (68) Ga-DOTA-Lys-Pteroyl and (68) Ga-DOTA-DAV-Lys-Pteroy were 10.06 ± 0.59%ID/g and 11.05 ± 0.60%ID/g at 2 h post-injection, respectively. Flank KB tumor was clearly visualized with (68) Ga-DOTA-DAV-Lys-Pteroyl by Micro-PET imaging at 2 h post-injection, suggesting the feasibility of using (68) Ga-labeled Pteroyl-Lys conjugates as a novel class of FR targeted probes. PMID:27320312

  5. Radiolabeling optimization and characterization of (68)Ga labeled DOTA-polyamido-amine dendrimer conjugate - Animal biodistribution and PET imaging results.

    PubMed

    Ghai, Aanchal; Singh, Baljinder; Panwar Hazari, Puja; Schultz, Michael K; Parmar, Ambika; Kumar, Pardeep; Sharma, Sarika; Dhawan, Devinder; Kumar Mishra, Anil

    2015-11-01

    The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA conjugate. A conjugate (PAMAM-DOTA) concentration of 11.69µM, provided best radiolabeling efficiency of more than 93.0% at pH 4.0, incubation time of 30.0min and reaction temperature ranging between 90 and 100°C. The decay corrected radiochemical yield was found to be 79.4±0.01%. The radiolabeled preparation ([(68)Ga]-DOTA-PAMAM-D) remained stable (radiolabeling efficiency of 96.0%) at room temperature and in serum for up to 4-h. The plasma protein binding was observed to be 21.0%. After intravenous administration, 50.0% of the tracer cleared from the blood circulation by 30-min and less than 1.0% of the injected activity remained in blood by 1.0h. The animal biodistribution studies demonstrated that the tracer excretes through the kidneys and about 0.33% of the %ID/g accumulated in the tumor at 1h post injection. The animal organ's biodistribution data was supported by animal PET imaging showing good 'non-specific' tracer uptake in tumor and excretion is primarily through kidneys. Additionally, DOTA-PAMAM-D conjugation with αVβ3 receptors targeting peptides and drug loading on the dendrimers may improve the specificity of the (68)Ga labeled product for imaging and treating angiogenesis respectively. PMID:26232562

  6. Evaluation of 68Ga-labeled MG7 antibody: a targeted probe for PET/CT imaging of gastric cancer.

    PubMed

    Xu, Bing; Li, Xiaowei; Yin, Jipeng; Liang, Cong; Liu, Lijuan; Qiu, Zhaoyan; Yao, Liping; Nie, Yongzhan; Wang, Jing; Wu, Kaichun

    2015-01-01

    MG7-Ag, a specific gastric cancer-associated antigen, can be used to non-invasively monitor gastric cancer by molecular imaging with positron emission tomography/computed tomography (PET/CT). In this study, we prepared and evaluated a (68)Ga-labeled MG7 antibody as a molecular probe for nanoPET/CT imaging of gastric cancer in a BGC-823 tumor xenografted mouse model. Macrocyclic chelator 1,4,7-triazacyclononane-N,N0,N00-triacetic acid (NOTA)-conjugated MG7 antibody was synthesized and radiolabeled with (68)Ga (t1/2 = 67.71 min). Then, (68)Ga-NOTA-MG7 was tested using in vitro cytological studies, in vivo nanoPET/CT and Cerenkov imaging studies as well as ex vivo biodistribution and histology studies. The in vitro experiments demonstrated that (68)Ga-NOTA-MG7 has an excellent radiolabeling efficiency of approximately 99% without purification, and it is stable in serum after 120 min of incubation. Cell uptake and retention studies confirmed that (68)Ga-NOTA-MG7 has good binding affinity and tumor cell retention. For the nanoPET imaging study, the predominant uptake of (68)Ga-NOTA-MG7 was visualized in tumor, liver and kidneys. The tumor uptake reached at its peak (2.53 ± 0.28%ID/g) at 60 min pi. Cherenkov imaging also confirmed the specificity of tumor uptake. Moreover, the biodistribution results were consistent with the quantification data of nanoPET/CT imaging. Histologic analysis also demonstrated specific staining of BGC-823 tumor cell lines. PMID:25733152

  7. Preclinical Comparative Study of (68)Ga-Labeled DOTA, NOTA, and HBED-CC Chelated Radiotracers for Targeting PSMA.

    PubMed

    Ray Banerjee, Sangeeta; Chen, Zhengping; Pullambhatla, Mrudula; Lisok, Ala; Chen, Jian; Mease, Ronnie C; Pomper, Martin G

    2016-06-15

    (68)Ga-labeled, low-molecular-weight imaging agents that target the prostate-specific membrane antigen (PSMA) are increasingly used clinically to detect prostate and other cancers with positron emission tomography (PET). The goal of this study was to compare the pharmacokinetics of three PSMA-targeted radiotracers: (68)Ga-1, using DOTA-monoamide as the chelating agent; (68)Ga-2, containing the macrocyclic chelating agent p-SCN-Bn-NOTA; and (68)Ga-DKFZ-PSMA-11, currently in clinical trials, which uses the acyclic chelating agent, HBED-CC. The PSMA-targeting scaffold for all three agents utilized a similar Glu-urea-Lys-linker construct. Each radiotracer enabled visualization of PSMA+ PC3 PIP tumor, kidney, and urinary bladder as early as 15 min post-injection using small animal PET/computed tomography (PET/CT). (68)Ga-2 demonstrated the fastest rate of clearance from all tissues in this series and displayed higher uptake in PSMA+ PC3 PIP tumor compared to (68)Ga-1 at 1 h post-injection. There was no significant difference in PSMA+ PC3 PIP tumor uptake for the three agents at 2 and 3 h post-injection. (68)Ga-DKFZ-PSMA-11 demonstrated the highest uptake and retention in normal tissues, including kidney, blood, spleen, and salivary glands and PSMA-negative PC3 flu tumors up to 3 h post-injection. In this preclinical evaluation (68)Ga-2 had the most advantageous characteristics for PSMA-targeted PET imaging. PMID:27076393

  8. Evaluation of 68Ga-Labeled MG7 Antibody: A Targeted Probe for PET/CT Imaging of Gastric Cancer

    PubMed Central

    Xu, Bing; Li, Xiaowei; Yin, Jipeng; Liang, Cong; Liu, Lijuan; Qiu, Zhaoyan; Yao, Liping; Nie, Yongzhan; Wang, Jing; Wu, Kaichun

    2015-01-01

    MG7-Ag, a specific gastric cancer-associated antigen, can be used to non-invasively monitor gastric cancer by molecular imaging with positron emission tomography/computed tomography (PET/CT). In this study, we prepared and evaluated a 68Ga-labeled MG7 antibody as a molecular probe for nanoPET/CT imaging of gastric cancer in a BGC-823 tumor xenografted mouse model. Macrocyclic chelator 1,4,7-triazacyclononane-N,N0,N00-triacetic acid (NOTA)-conjugated MG7 antibody was synthesized and radiolabeled with 68Ga (t1/2 = 67.71 min). Then, 68Ga-NOTA-MG7 was tested using in vitro cytological studies, in vivo nanoPET/CT and Cerenkov imaging studies as well as ex vivo biodistribution and histology studies. The in vitro experiments demonstrated that 68Ga-NOTA-MG7 has an excellent radiolabeling efficiency of approximately 99% without purification, and it is stable in serum after 120 min of incubation. Cell uptake and retention studies confirmed that 68Ga-NOTA-MG7 has good binding affinity and tumor cell retention. For the nanoPET imaging study, the predominant uptake of 68Ga-NOTA-MG7 was visualized in tumor, liver and kidneys. The tumor uptake reached at its peak (2.53 ± 0.28%ID/g) at 60 min pi. Cherenkov imaging also confirmed the specificity of tumor uptake. Moreover, the biodistribution results were consistent with the quantification data of nanoPET/CT imaging. Histologic analysis also demonstrated specific staining of BGC-823 tumor cell lines. PMID:25733152

  9. Affinity of (nat/68)Ga-Labelled Curcumin and Curcuminoid Complexes for β-Amyloid Plaques: Towards the Development of New Metal-Curcumin Based Radiotracers.

    PubMed

    Rubagotti, Sara; Croci, Stefania; Ferrari, Erika; Iori, Michele; Capponi, Pier C; Lorenzini, Luca; Calzà, Laura; Versari, Annibale; Asti, Mattia

    2016-01-01

    Curcumin derivatives labelled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Nevertheless, no study by exploiting the labelling with gallium-68 has been performed so far, in spite of its suitable properties (positron emitter, generator produced radionuclide). Herein, an evaluation of the affinity for synthetic β-amyloid fibrils and for amyloid plaques of three (nat/68)Ga-labelled curcumin analogues, namely curcumin curcumin (CUR), bis-dehydroxy-curcumin (bDHC) and diacetyl-curcumin (DAC), was performed. Affinity and specificity were tested in vitro on amyloid synthetic fibrils by using gallium-68 labelled compounds. Post-mortem brain cryosections from Tg2576 mice were used for the ex vivo visualization of amyloid plaques. The affinity of (68)Ga(CUR)₂⁺, (68)Ga(DAC)₂⁺, and (68)Ga(bDHC)₂⁺ for synthetic β-amyloid fibrils was moderate and their uptake could be observed in vitro. On the other hand, amyloid plaques could not be visualized on brain sections of Tg2576 mice after injection, probably due to the low stability of the complexes in vivo and of a hampered passage through the blood-brain barrier. Like curcumin, all (nat/68)Ga-curcuminoid complexes maintain a high affinity for β-amyloid plaques. However, structural modifications are still needed to improve their applicability as radiotracers in vivo. PMID:27608011

  10. "Click"-cyclized (68)Ga-labeled peptides for molecular imaging and therapy: synthesis and preliminary in vitro and in vivo evaluation in a melanoma model system.

    PubMed

    Martin, Molly E; Sue O'Dorisio, M; Leverich, Whitney M; Kloepping, Kyle C; Walsh, Susan A; Schultz, Michael K

    2013-01-01

    Cyclization techniques are used often to impart higher in vivo stability and binding affinity to peptide targeting vectors for molecular imaging and therapy. The two most often used techniques to impart these qualities are lactam bridge construction and disulfide bond formation. While these techniques have been demonstrated to be effective, orthogonal protection/deprotection steps can limit achievable product yields. In the work described in this chapter, new α-melanocyte stimulating hormone (α-MSH) peptide analogs were synthesized and cyclized by copper-catalyzed terminal azide-alkyne cycloaddition "click" chemistry techniques. The α-MSH peptide and its cognate receptor (melanocortin receptor subtype 1, MC1R) represent a well-characterized model system to examine the effect of the triazole linkage for peptide cyclization on receptor binding in vitro and in vivo. Four new DOTA-conjugated α-MSH analogs were cyclized and evaluated by in vitro competitive binding assays, serum stability testing, and in vivo imaging by positron emission tomography (PET) of tumor-bearing mice. These new DOTA-conjugated click-cyclized analogs exhibited selective high binding affinity (<2 nM) for MC1R on melanoma cells in vitro, high stability in human serum, and produced high-contrast PET/CT images of tumor xenografts. (68)Ga-labeled DOTA bioconjugates displayed rapid pharmacokinetics with receptor-mediated tumor accumulation of up to 16 ± 5% ID/g. The results indicate that the triazole ring is an effective bioisosteric replacement for the standard lactam bridge assemblage for peptide cyclization. Radiolabeling results confirm that Cu catalyst is sufficiently removed prior to DOTA chelator addition to enable insertion of radio metals or stable metals for molecular imaging and therapy. Thus, these click-chemistry-cyclized variants show promise as agents for melanocortin receptor-targeted imaging and radionuclide therapy. PMID:22918759

  11. Feasibility of 68Ga-labeled Siglec-9 peptide for the imaging of acute lung inflammation: a pilot study in a porcine model of acute respiratory distress syndrome

    PubMed Central

    Retamal, Jaime; Sörensen, Jens; Lubberink, Mark; Suarez-Sipmann, Fernando; Borges, João Batista; Feinstein, Ricardo; Jalkanen, Sirpa; Antoni, Gunnar; Hedenstierna, Göran; Roivainen, Anne; Larsson, Anders; Velikyan, Irina

    2016-01-01

    There is an unmet need for noninvasive, specific and quantitative imaging of inherent inflammatory activity. Vascular adhesion protein-1 (VAP-1) translocates to the luminal surface of endothelial cells upon inflammatory challenge. We hypothesized that in a porcine model of acute respiratory distress syndrome (ARDS), positron emission tomography (PET) with sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) based imaging agent targeting VAP-1 would allow quantification of regional pulmonary inflammation. ARDS was induced by lung lavages and injurious mechanical ventilation. Hemodynamics, respiratory system compliance (Crs) and blood gases were monitored. Dynamic examination using [15O]water PET-CT (10 min) was followed by dynamic (90 min) and whole-body examination using VAP-1 targeting 68Ga-labeled 1,4,7,10-tetraaza cyclododecane-1,4,7-tris-acetic acid-10-ethylene glycol-conjugated Siglec-9 motif peptide ([68Ga]Ga-DOTA-Siglec-9). The animals received an anti-VAP-1 antibody for post-mortem immunohistochemistry assay of VAP-1 receptors. Tissue samples were collected post-mortem for the radioactivity uptake, histology and immunohistochemistry assessment. Marked reduction of oxygenation and Crs, and higher degree of inflammation were observed in ARDS animals. [68Ga]Ga-DOTA-Siglec-9 PET showed significant uptake in lungs, kidneys and urinary bladder. Normalization of the net uptake rate (Ki) for the tissue perfusion resulted in 4-fold higher uptake rate of [68Ga]Ga-DOTA-Siglec-9 in the ARDS lungs. Immunohistochemistry showed positive VAP-1 signal in the injured lungs. Detection of pulmonary inflammation associated with a porcine model of ARDS was possible with [68Ga]Ga-DOTA-Siglec-9 PET when using kinetic modeling and normalization for tissue perfusion. PMID:27069763

  12. Feasibility of (68)Ga-labeled Siglec-9 peptide for the imaging of acute lung inflammation: a pilot study in a porcine model of acute respiratory distress syndrome.

    PubMed

    Retamal, Jaime; Sörensen, Jens; Lubberink, Mark; Suarez-Sipmann, Fernando; Borges, João Batista; Feinstein, Ricardo; Jalkanen, Sirpa; Antoni, Gunnar; Hedenstierna, Göran; Roivainen, Anne; Larsson, Anders; Velikyan, Irina

    2016-01-01

    There is an unmet need for noninvasive, specific and quantitative imaging of inherent inflammatory activity. Vascular adhesion protein-1 (VAP-1) translocates to the luminal surface of endothelial cells upon inflammatory challenge. We hypothesized that in a porcine model of acute respiratory distress syndrome (ARDS), positron emission tomography (PET) with sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) based imaging agent targeting VAP-1 would allow quantification of regional pulmonary inflammation. ARDS was induced by lung lavages and injurious mechanical ventilation. Hemodynamics, respiratory system compliance (Crs) and blood gases were monitored. Dynamic examination using [(15)O]water PET-CT (10 min) was followed by dynamic (90 min) and whole-body examination using VAP-1 targeting (68)Ga-labeled 1,4,7,10-tetraaza cyclododecane-1,4,7-tris-acetic acid-10-ethylene glycol-conjugated Siglec-9 motif peptide ([(68)Ga]Ga-DOTA-Siglec-9). The animals received an anti-VAP-1 antibody for post-mortem immunohistochemistry assay of VAP-1 receptors. Tissue samples were collected post-mortem for the radioactivity uptake, histology and immunohistochemistry assessment. Marked reduction of oxygenation and Crs, and higher degree of inflammation were observed in ARDS animals. [(68)Ga]Ga-DOTA-Siglec-9 PET showed significant uptake in lungs, kidneys and urinary bladder. Normalization of the net uptake rate (Ki) for the tissue perfusion resulted in 4-fold higher uptake rate of [(68)Ga]Ga-DOTA-Siglec-9 in the ARDS lungs. Immunohistochemistry showed positive VAP-1 signal in the injured lungs. Detection of pulmonary inflammation associated with a porcine model of ARDS was possible with [(68)Ga]Ga-DOTA-Siglec-9 PET when using kinetic modeling and normalization for tissue perfusion. PMID:27069763

  13. In vitro autoradiography of carcinoembryonic antigen in tissue from patients with colorectal cancer using multifunctional antibody TF2 and 67/68Ga-labeled haptens by pretargeting

    PubMed Central

    Hall, Håkan; Velikyan, Irina; Blom, Elisabeth; Ulin, Johan; Monazzam, Azita; Påhlman, Lars; Micke, Patrick; Wanders, Alkwin; McBride, William; Goldenberg, David M.; Långström, Bengt

    2012-01-01

    The carcinoembryonic antigen (CEA) was visualized in vitro in tissue from patients with colorectal cancer with trivalent bispecific antibody TF2 and two hapten molecules, [67/68Ga]Ga-IMP461 and [67/68Ga]Ga-IMP485 by means of pretargeting. Colorectal cancer tissue samples obtained from surgery at Uppsala University Hospital, were frozen fresh and cryosectioned. The two hapten molecules comprising 1,4,7-triazacyclononanetriacetic acid chelate moiety (NOTA) were labeled with 67Ga or 68Ga. The autoradiography was conducted by incubating the tissue samples with the bispecific antibody TF2, followed by washing and incubation with one of the radiolabeled hapten molecules. After washing, drying and exposure to phosphor imager plates, the autoradiograms were analyzed and compared to standard histochemistry (hematoxylin-eosin). Pronounced binding was found in the tissue from colorectal cancer using the bispecific antibody TF2 and either of the haptens [67/68Ga]Ga-IMP461 and [67/68Ga]Ga-IMP485. Distinct binding was also detected in the epithelium of most samples of neighboring tissue, taken at a minimum of 10 cm from the site of the tumor. It is concluded that pretargeting CEA with the bispecific antibody TF2 followed by the addition of 67/68Ga-labeled hapten is extremely sensitive for visualizing this marker for colorectal cancer. This methodology is therefore a very specific complement to other histochemical techniques in the diagnosis of biopsies or in samples taken from surgery. Use of the pretargeting technique in vivo may also be an advance in diagnosing patients with colorectal cancer, either using 67Ga and SPECT or 68Ga and PET. PMID:23133809

  14. Synthesis and characterization of (68)Ga-labeled curcumin and curcuminoid complexes as potential radiotracers for imaging of cancer and Alzheimer's disease.

    PubMed

    Asti, Mattia; Ferrari, Erika; Croci, Stefania; Atti, Giulia; Rubagotti, Sara; Iori, Michele; Capponi, Pier C; Zerbini, Alessandro; Saladini, Monica; Versari, Annibale

    2014-05-19

    Curcumin (CUR) and curcuminoids complexes labeled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Gallium-68 is a positron-emitting, generator-produced radionuclide, and its properties can be exploited in situ in medical facilities without a cyclotron. Moreover, CUR showed a higher uptake in tumor cells compared to normal cells, suggesting potential diagnostic applications in this field. In spite of this, no studies using labeled CUR have been performed in this direction, so far. Herein, (68)Ga-labeled complexes with CUR and two curcuminoids, namely diacetyl-curcumin (DAC) and bis(dehydroxy)curcumin (bDHC), were synthesized and characterized by means of experimental and theoretical approaches. Moreover, a first evaluation of their affinity to synthetic β-amyloid fibrils and uptake by A549 lung cancer cells was performed to show the potential application of these new labeled curcuminoids in these diagnostic fields. The radiotracers were prepared by reacting (68)Ga(3+) obtained from a (68)Ge/(68)Ga generator with 1 mg/mL curcuminoids solutions. Reaction parameters (precursor amount, reaction temperature, and pH) were optimized to obtain high and reproducible radiochemical yield and purity. Stoichiometry and formation of the curcuminoid complexes were investigated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, NMR, ultraviolet-visible, and fluorescence spectroscopy on the equivalent (nat)Ga-curcuminoids (nat = natural) complexes, and their structure was computed by theoretical density functional theory calculations. The analyses evidenced that CUR, DAC, and bDHC were predominantly in the keto-enol form and attested to Ga(L)2(+) species formation. Identity of the (68)Ga(L)2(+) complexes was confirmed by coelution with the equivalent (nat)Ga(L)2(+) complexes in ultrahigh-performance liquid chromatography analyses.(68)Ga(CUR)2(+), (68)Ga(DAC)2(+), and (68)Ga(bDHC)2

  15. Validating and improving CT ventilation imaging by correlating with ventilation 4D-PET/CT using {sup 68}Ga-labeled nanoparticles

    SciTech Connect

    Kipritidis, John Keall, Paul J.; Siva, Shankar; Hofman, Michael S.; Callahan, Jason; Hicks, Rodney J.

    2014-01-15

    Purpose: CT ventilation imaging is a novel functional lung imaging modality based on deformable image registration. The authors present the first validation study of CT ventilation using positron emission tomography with{sup 68}Ga-labeled nanoparticles (PET-Galligas). The authors quantify this agreement for different CT ventilation metrics and PET reconstruction parameters. Methods: PET-Galligas ventilation scans were acquired for 12 lung cancer patients using a four-dimensional (4D) PET/CT scanner. CT ventilation images were then produced by applying B-spline deformable image registration between the respiratory correlated phases of the 4D-CT. The authors test four ventilation metrics, two existing and two modified. The two existing metrics model mechanical ventilation (alveolar air-flow) based on Hounsfield unit (HU) change (V{sub HU}) or Jacobian determinant of deformation (V{sub Jac}). The two modified metrics incorporate a voxel-wise tissue-density scaling (ρV{sub HU} and ρV{sub Jac}) and were hypothesized to better model the physiological ventilation. In order to assess the impact of PET image quality, comparisons were performed using both standard and respiratory-gated PET images with the former exhibiting better signal. Different median filtering kernels (σ{sub m} = 0 or 3 mm) were also applied to all images. As in previous studies, similarity metrics included the Spearman correlation coefficient r within the segmented lung volumes, and Dice coefficient d{sub 20} for the (0 − 20)th functional percentile volumes. Results: The best agreement between CT and PET ventilation was obtained comparing standard PET images to the density-scaled HU metric (ρV{sub HU}) with σ{sub m} = 3 mm. This leads to correlation values in the ranges 0.22 ⩽ r ⩽ 0.76 and 0.38 ⩽ d{sub 20} ⩽ 0.68, with r{sup ¯}=0.42±0.16 and d{sup ¯}{sub 20}=0.52±0.09 averaged over the 12 patients. Compared to Jacobian-based metrics, HU-based metrics lead to statistically significant

  16. High specific activity silicon-32

    DOEpatents

    Phillips, D.R.; Brzezinski, M.A.

    1996-06-11

    A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidation state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  17. High specific activity silicon-32

    DOEpatents

    Phillips, Dennis R.; Brzezinski, Mark A.

    1996-01-01

    A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  18. (67/68)Ga-labeling agent that liberates (67/68)Ga-NOTA-methionine by lysosomal proteolysis of parental low molecular weight polypeptides to reduce renal radioactivity levels.

    PubMed

    Uehara, Tomoya; Rokugawa, Takemi; Kinoshita, Mai; Nemoto, Souki; Fransisco Lazaro, Guerra Gomez; Hanaoka, Hirofumi; Arano, Yasushi

    2014-11-19

    The renal localization of gallium-67 or gallium-68 ((67/68)Ga)-labeled low molecular weight (LMW) probes such as peptides and antibody fragments constitutes a problem in targeted imaging. Wu et al. previously showed that (67)Ga-labeled S-2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (SCN-Bz-NOTA)-conjugated methionine ((67)Ga-NOTA-Met) was rapidly excreted from the kidney in urine following lysosomal proteolysis of the parental (67)Ga-NOTA-Bz-SCN-disulfide-stabilized Fv fragment (Bioconjugate Chem., (1997) 8, 365-369). In the present study, a new (67/68)Ga-labeling reagent for LMW probes that liberates (67/68)Ga-NOTA-Met was designed, synthesized, and evaluated using longer-lived (67)Ga in order to reduce renal radioactivity levels. We employed a methionine-isoleucine (MI) dipeptide bond as the cleavable linkage. The amine residue of MI was coupled with SCN-Bz-NOTA for (67)Ga-labeling, while the carboxylic acid residue of MI was derivatized to maleimide for antibody conjugation in order to synthesize NOTA-MI-Mal. A Fab fragment of the anti-Her2 antibody was thiolated with iminothiolane, and NOTA-MI-Mal was conjugated with the antibody fragment by maleimide-thiol chemistry. The Fab fragment was also conjugated with SCN-Bz-NOTA (NOTA-Fab) for comparison. (67)Ga-NOTA-MI-Fab was obtained at radiochemical yields of over 95% and was stable in murine serum for 24 h. In the biodistribution study using normal mice, (67)Ga-NOTA-MI-Fab registered significantly lower renal radioactivity levels from 1 to 6 h postinjection than those of (67)Ga-NOTA-Fab. An analysis of urine samples obtained 6 h after the injection of (67)Ga-NOTA-MI-Fab showed that the majority of radioactivity was excreted as (67)Ga-NOTA-Met. In the biodistribution study using tumor-bearing mice, the tumor to kidney ratios of (67)Ga-NOTA-MI-Fab were 4 times higher (6 h postinjection) than those of (67)Ga-NOTA-Fab. Although further studies including the structure of radiometabolites and

  19. Production of high specific activity silicon-32

    SciTech Connect

    Phillips, D.R.; Brzezinski, M.A.

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development Project (LDRD) at Los Alamos National Laboratory (LANL). There were two primary objectives for the work performed under this project. The first was to take advantage of capabilities and facilities at Los Alamos to produce the radionuclide {sup 32}Si in unusually high specific activity. The second was to combine the radioanalytical expertise at Los Alamos with the expertise at the University of California to develop methods for the application of {sup 32}Si in biological oceanographic research related to global climate modeling. The first objective was met by developing targetry for proton spallation production of {sup 32}Si in KCl targets and chemistry for its recovery in very high specific activity. The second objective was met by developing a validated field-useable, radioanalytical technique, based upon gas-flow proportional counting, to measure the dynamics of silicon uptake by naturally occurring diatoms.

  20. Production Of High Specific Activity Copper-67

    DOEpatents

    Jamriska, Sr., David J.; Taylor, Wayne A.; Ott, Martin A.; Fowler, Malcolm; Heaton, Richard C.

    2003-10-28

    A process for the selective production and isolation of high specific activity Cu.sup.67 from proton-irradiated enriched Zn.sup.70 target comprises target fabrication, target irradiation with low energy (<25 MeV) protons, chemical separation of the Cu.sup.67 product from the target material and radioactive impurities of gallium, cobalt, iron, and stable aluminum via electrochemical methods or ion exchange using both anion and cation organic ion exchangers, chemical recovery of the enriched Zn.sup.70 target material, and fabrication of new targets for re-irradiation is disclosed.

  1. Production Of High Specific Activity Copper-67

    DOEpatents

    Jamriska, Sr., David J.; Taylor, Wayne A.; Ott, Martin A.; Fowler, Malcolm; Heaton, Richard C.

    2002-12-03

    A process for the selective production and isolation of high specific activity cu.sup.67 from proton-irradiated enriched Zn.sup.70 target comprises target fabrication, target irradiation with low energy (<25 MeV) protons, chemical separation of the Cu.sup.67 product from the target material and radioactive impurities of gallium, cobalt, iron, and stable aluminum via electrochemical methods or ion exchange using both anion and cation organic ion exchangers, chemical recovery of the enriched Zn.sup.70 target material, and fabrication of new targets for re-irradiation is disclosed.

  2. Production of high specific activity silicon-32

    DOEpatents

    Phillips, Dennis R.; Brzezinski, Mark A.

    1994-01-01

    A process for preparation of silicon-32 is provide and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  3. Production of high specific activity silicon-32

    SciTech Connect

    Phillips, D.R.; Brzezinski, M.A.

    1994-09-13

    A process for the preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  4. Method of preparing high specific activity platinum-195m

    DOEpatents

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-06-15

    A method of preparing high-specific-activity .sup.195m Pt includes the steps of: exposing .sup.193 Ir to a flux of neutrons sufficient to convert a portion of the .sup.193 Ir to .sup.195m Pt to form an irradiated material; dissolving the irradiated material to form an intermediate solution comprising Ir and Pt; and separating the Pt from the Ir by cation exchange chromatography to produce .sup.195m Pt.

  5. Method for preparing high specific activity 177Lu

    SciTech Connect

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-04-06

    A method of separating lutetium from a solution containing Lu and Yb, particularly reactor-produced .sup.177 Lu and .sup.177 Yb, includes the steps of: providing a chromatographic separation apparatus containing LN resin; loading the apparatus with a solution containing Lu and Yb; and eluting the apparatus to chromatographically separate the Lu and the Yb in order to produce high-specific-activity .sup.177 Yb.

  6. Synthesis of a high specific activity methyl sulfone tritium isotopologue of fevipiprant (NVP-QAW039).

    PubMed

    Luu, Van T; Goujon, Jean-Yves; Meisterhans, Christian; Frommherz, Matthias; Bauer, Carsten

    2015-05-15

    The synthesis of a triple tritiated isotopologue of the CRTh2 antagonist NVP-QAW039 (fevipiprant) with a specific activity >3 TBq/mmol is described. Key to the high specific activity is the methylation of a bench-stable dimeric disulfide precursor that is in situ reduced to the corresponding thiol monomer and methylated with [(3)H3]MeONos having per se a high specific activity. The high specific activity of the tritiated active pharmaceutical ingredient obtained by a build-up approach is discussed in the light of the specific activity usually to be expected if hydrogen tritium exchange methods were applied. PMID:25881897

  7. Chemical synthesis of nucleoside-gamma-[32P]triphosphates of high specific activity.

    PubMed

    Janecka, A; Panusz, H; Pankowski, J; Koziołkiewicz, W

    1980-01-01

    A simple chemical procedure for the preparation of four common ribonucleoside 5-gamma-[32P]triphosphates of high specific activity (up to 10 Ci/mmole) based on the condensation of orthophosphoric acid with the corresponding nucleoside 5-diphosphate in the presence of ethyl chloroformate as well as the methods of purification and identification of the products are described. PMID:7375446

  8. Production of 191Pt radiotracer with high specific activity for the development of preconcentration procedures

    NASA Astrophysics Data System (ADS)

    Parent, M.; Strijckmans, K.; Cornelis, R.; Dewaele, J.; Dams, R.

    1994-04-01

    A radiotracer of Pt with suitable nuclear characteristics and high specific activity (i.e. activity to mass ratio) is a powerful tool when developing preconcentration methods for the determination of base-line levels of Pt in e.g. environmental and biological samples. Two methods were developed for the production of 191Pt with high specific activity and radionuclidic purity: (1) via the 190Pt(n, γ) 191Pt reaction by neutron irradiation of enriched Pt in a nuclear reactor at high neutron fluence rate and (2) via the 191Ir(p, n) 191Pt reaction by proton irradiation of natural Ir with a cyclotron, at an experimentally optimized proton energy. For the latter method it was necessary to separate Pt from the Ir matrix. For that reason either liquid-liquid extraction with dithizone or adsorption chromatography were used. The yields, the specific activities and the radionuclidic purities were experimentally determined as a function of the proton energy and compared to the former method. The half-life of 191Pt was accurately determined to be 2.802 ± 0.025 d.

  9. Synthesis of high specific activity (1- sup 3 H) farnesyl pyrophosphate

    SciTech Connect

    Saljoughian, M.; Morimoto, H.; Williams, P.G.

    1991-08-01

    The synthesis of tritiated farnesyl pyrophosphate with high specific activity is reported. trans-trans Farnesol was oxidized to the corresponding aldehyde followed by reduction with lithium aluminium tritide (5%-{sup 3}H) to give trans-trans (1-{sup 3}H)farnesol. The specific radioactivity of the alcohol was determined from its triphenylsilane derivative, prepared under very mild conditions. The tritiated alcohol was phosphorylated by initial conversion to an allylic halide, and subsequent treatment of the halide with tris-tetra-n-butylammonium hydrogen pyrophosphate. The hydride procedure followed in this work has advantages over existing methods for the synthesis of tritiated farnesyl pyrophosphate, with the possibility of higher specific activity and a much higher yield obtained. 10 refs., 3 figs.

  10. Cyclotron production of ``very high specific activity'' platinum radiotracers in No Carrier Added form

    NASA Astrophysics Data System (ADS)

    Birattari, C.; Bonardi, M.; Groppi, F.; Gini, L.; Gallorini, M.; Sabbioni, E.; Stroosnijder, M. F.

    2001-12-01

    At the "Radiochemistry Laboratory" of Accelerators and Applied Superconductivity Laboratory, LASA, several production and quality assurance methods for short-lived and high specific activity radionuclides, have been developed. Presently, the irradiations are carried out at the Scanditronix MC40 cyclotron (K=38; p, d, He-4 and He-3) of JRC-Ispra, Italy, of the European Community, while both chemical purity and specific activity determination are carried out at the TRIGA MARK II research reactor of University of Pavia and at LASA itself. In order to optimize the irradiation conditions for platinum radiotracer production, both thin- and thick-target excitation function of natOs(α,xn) nuclear reactions were measured. A very selective radiochemical separation to obtain Pt radiotracers in No Carrier Added form, has been developed. Both real specific activity and chemical purity of radiotracer, have been determined by neutron activation analysis and atomic absorption spectrometry. An Isotopic Dilution Factor (IDF) of the order of 50 is achieved.

  11. Production of radiohalogens and [11C]-methane at high specific activity

    NASA Astrophysics Data System (ADS)

    Nye, Jonathon Andrew

    2005-07-01

    The halogens, occupying Group VII of the periodic table, play an important role in the biochemical processes underlying health and disease. A variety of positron emitters covering a broad range of half-lives permit the imaging of the body's physiochemical behavior using PET. Neutron deficient isotopes of the halogen group can be produced by (p,n) reactions from enriched targets with low energy (<13MeV) biomedical cyclotrons. These cyclotrons are distributed relatively evenly throughout the United States at research institutions and commercial distribution sites (i.e., 100+ CTI RDS 11MeV proton cyclotrons). However, these sites concentrate on the core group of positron emitters: 15O, 13N, 11C, and primarily 18F-fluoride. The simplicity of the production process insures their role in the clinical/research environment, labeling H215 O, 13NH3, CH3-compounds and 18F-FDG. Halogens with half-lives longer than 18F have been avoided due to a combination of several factors, such as complexity of the target systems, expense of the enriched substrate, low reaction yields, and extensive post-processing to reclaim the target material. PET research over the last decade has forced a match between drug development and emerging small animal instrumentation, shifting focus to agents labeled with high specific activity 11CH3I and the long-lived radiohalogens, 76Br and 124I. A steady local supply of 18F-fluoride, 11C-methane, 76B-bromide, and 124I-iodide is essential to seize today's research opportunities or for limited distribution outside of our local area. To keep pace, new targetry developments are implemented to reliably produce these isotopes on a batch basis. The research presented details improvements on existing production methods for 18F-fluoride intended for nucleophilic substitution and high specific activity 11C-methane (→CH3I) for the N-methylation of a half-dozen neuroligands. A significant effort is placed on the novel use of low energy cyclotrons for the production

  12. Simple procedure for the synthesis of high specific activity tritiated (6S)-5-formyltetrahydrofolate

    SciTech Connect

    Moran, R.G.; Colman, P.D.

    1982-05-01

    The 5-position of tetrahydrofolate was found to be unusually reactive with low concentrations of formic acid in the presence of a water-soluble carbodiimide. The product of this reaction has neutral and acid ultraviolet spectra and chromatographic behavior consistent with its identity as 5-formyltetrahydrofolate (leucovoriun). When enzymatically synthesized (6S)-tetrahydrofolate was used as starting material, the product supported the growth of folate-depleted L1210 cells at one-half the concentration required for authentic (6R,S)-leucovorin. This reaction has been used to produce high specific activity (44 Ci/mmol) (/sup 3/H)(6S)-5-formyltetrahydrofolate in high yield. Experiments with (/sup 14/C)formic acid indicate that 1 mol of formate reacted per mol of tetrahydrofolate but that no reaction occurred with a variety of other folate compounds. (6S)-5-Formyltetrahydrofolate, labeled in the formyl group with /sup 14/C, has also been synthesized using this reaction. These easily produced, labeled folates should allow close examination of the transport and utilization of leucovorin and of the mechanism of reversal of methotrexate toxicity by reduced folate cofactors.

  13. High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay

    SciTech Connect

    Prestwich, G.D.; Wawrzenczyk, C.

    1985-08-01

    A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites.

  14. How to produce high specific activity tin-117m using alpha particle beam.

    PubMed

    Duchemin, C; Essayan, M; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2016-09-01

    Tin-117m is an interesting radionuclide for both diagnosis and therapy, thanks to the gamma-ray and electron emissions, respectively, resulting from its decay to tin-117g. The high specific activity of tin-117m is required in many medical applications, and it can be obtained using a high energy alpha particle beam and a cadmium target. The experiments performed at the ARRONAX cyclotron (Nantes, France) using an alpha particle beam delivered at 67.4MeV provide a measurement of the excitation function of the Cd-nat(α,x)Sn-117m reaction and the produced contaminants. The Cd-116(α,3n)Sn-117m production cross section has been deduced from these experimental results using natural cadmium. Both production yield and specific activity as a function of the projectile energy have been calculated. These informations help to optimize the irradiation conditions to produce tin-117m with the required specific activity using α particles with a cadmium target. PMID:27344526

  15. High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay.

    PubMed Central

    Prestwich, G D; Wawrzeńczyk, C

    1985-01-01

    A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites. PMID:3860862

  16. Penicillin V acylase from Pectobacterium atrosepticum exhibits high specific activity and unique kinetics.

    PubMed

    Avinash, V S; Ramasamy, Sureshkumar; Suresh, C G; Pundle, Archana

    2015-08-01

    Penicillin V acylases (PVAs, E.C.3.5.11) belong to the Ntn hydrolase super family of enzymes that catalyze the deacylation of the side chain from phenoxymethyl penicillin (penicillin V). Penicillin acylases find use in the pharmaceutical industry for the production of semi-synthetic antibiotics. PVAs employ the N-terminal cysteine residue as catalytic nucleophile and are structurally and evolutionarily related to bile salt hydrolases (BSHs). Here, we report the cloning and characterization of a PVA enzyme from the Gram-negative plant pathogen, Pectobacterium atrosepticum (PaPVA). The enzyme was cloned and expressed in Escherichia coli attaining a very high yield (250 mg/l) and a comparatively high specific activity (430 IU/mg). The enzyme showed marginally better pH and thermo-stability over PVAs characterized from Gram-positive bacteria. The enzyme also showed enhanced activity in presence of organic solvents and detergents. The enzyme kinetics turned out to be significantly different from that of previously reported PVAs, displaying positive cooperativity and substrate inhibition. The presence of bile salts had a modulating effect on PaPVA activity. Sequence analysis and characterization reveal the distinctive nature of these enzymes and underscore the need to study PVAs from Gram-negative bacteria. PMID:25931393

  17. Preparation and immunoreactivity of high specific activity indium-111-DTPA labeled monoclonal antibody (MoAb) using ultrapure indium-111

    SciTech Connect

    Zoghbi, S.S.; Neumann, R.D.; Gottschalk, A.

    1986-10-01

    The preparation of high-specific activity /sup 111/In-DTPA-MoAb without increasing the number of DTPA molecules per Ab was investigated. Instant thin layer chromatography was used to assay the relationship between labeling efficiencies and specific activities. With ultrapurified /sup 111/In, the specific activity of the radiolabeled MoAb approached the expected theoretic maximum of 100 muCi/microgram. The bioactivity of such high-specific activity preparation showed no degradation as measured by in vitro cell binding assay.

  18. (68)Ga-labeled 3PRGD2 for dual PET and Cerenkov luminescence imaging of orthotopic human glioblastoma.

    PubMed

    Fan, Di; Zhang, Xin; Zhong, Lijun; Liu, Xujie; Sun, Yi; Zhao, Huiyun; Jia, Bing; Liu, Zhaofei; Zhu, Zhaohui; Shi, Jiyun; Wang, Fan

    2015-06-17

    β-Emitters can produce Cerenkov radiation that is detectable by Cerenkov luminescence imaging (CLI), allowing the combination of PET and CLI with one radiotracer for both tumor diagnosis and visual guidance during surgery. Recently, the clinical feasibility of CLI with the established therapeutic reagent Na(131)I and the PET tracer (18)F-FDG was demonstrated. (68)Ga possesses a higher Cerenkov light output than (18)F and (131)I, which would result in higher sensitivity for CLI and improve the outcome of CLI in clinical applications. However, the research on (68)Ga-based tumor-specific tracers for CLI is limited. In this study, we examined the use of (68)Ga-radiolabeled DOTA-3PRGD2 ((68)Ga-3PRGD2) for dual PET and CLI of orthotopic U87MG human glioblastoma. For this purpose, the Cerenkov efficiencies of (68)Ga and (18)F were measured with the IVIS Spectrum system (PerkinElmer, USA). The CLI signal intensity of (68)Ga was 15 times stronger than that of (18)F. PET and CLI of (68)Ga-3PRGD2 were performed in U87MG human glioblastoma xenografts. Both PET and CLI revealed a remarkable accumulation of (68)Ga-3PRGD2 in the U87MG human glioblastoma xenografts at 1 h p.i. with an extremely low background in the brain when compared with (18)F-FDG. Furthermore, (68)Ga-3PRGD2 was used for dual PET and CLI of orthotopic human glioblastoma. The orthotopic human glioblastoma was clearly visualized by both imaging modalities. In addition, the biodistribution of (68)Ga-3PRGD2 was assessed in normal mice to estimate the radiation dosimetry. The whole-body effective dose is 20.1 ± 3.3 μSv/MBq, which is equal to 3.7 mSv per whole-body PET scan with a 5 mCi injection dose. Thus, (68)Ga-3PRGD2 involves less radiation exposure in patients when compared with (18)F-FDG (7.0 mSv). The use of (68)Ga-3PRGD2 in dual PET and CLI shows great promise for tumor diagnosis and image-guided surgery. PMID:25853280

  19. Application and dosimetric requirements for 68Ga-labeled somatostatin analogues in targeted radionuclide therapy for gastroenteropancreatic neuroendocrine tumors

    PubMed Central

    Taïeb, David; Garrigue, Philippe; Bardiès, Manuel; Esmaeel, Abdullah Ahmad; Pacak, Karel

    2015-01-01

    Neuroendocrine tumors (NETs) are associated with variable prognosis, with grade 1 and 2 NETs having a more favorable outcome than G3 ones (also called carcinoma). GEP-NET patients need highly individualized interdisciplinary evaluations and treatment. New treatment options have become available (i.e., sunitinib, mTOR inhibitors) with significant improvements in progression-free survival. Peptide receptor radionuclide therapy (PRRT) using 90Y or 177Lu-labeled somatostatin analogs has also shown promise in the treatment of advanced progressive NETs but randomized clinical trials comparing with other modalities are still lacking. SST-targeting represents the essence of theranostics. 68Ga-DOTA-SSTa can be used as companion imaging agents to assist in such a radionuclide therapy selection. 68Ga-DOTA-SSTa PET/CT might also provide critical information for prognosis, tumor response assessement to PRRT, and internal dosimetry. It is also expected that the development of novel receptor-targeting radiopharmaceuticals will contribute to the development of molecular-based personalized medicine approaches. PMID:26384594

  20. Synthesis of high specific activity (+)- and (-)-6-( sup 18 F)fluoronorepinephrine via the nucleophilic aromatic substitution reaction

    SciTech Connect

    Ding, Y.S.; Fowler, J.S.; Gatley, S.J.; Dewey, S.L.; Wolf, A.P. )

    1991-02-01

    The first example of a no-carrier-added {sup 18}F-labeled catecholamine, 6-({sup 18}F)fluoronorepinephrine (6-({sup 18}F)FNE), has been synthesized via nucleophilic aromatic substitution. The racemic mixture was resolved on a chiral HPLC column to obtain pure samples of (-)-6-({sup 18}F)FNE and (+)6-({sup 18}F)FNE. Radiochemical yields of 20% at the end of bombardment (EOB) for the racemic mixture (synthesis time 93 min), 6% for each enantiomer (synthesis time 128 min) with a specific activity of 2-5 Ci/mumol at EOB were obtained. Chiral HPLC peak assignment for the resolved enantiomers was achieved by using two independent methods: polarimetric determination and reaction with dopamine beta-hydroxylase. Positron emission tomography (PET) studies with racemic 6-({sup 18}F)FNE show high uptake and retention in the baboon heart. This work demonstrates that nucleophilic aromatic substitution by ({sup 18}F)fluoride ion is applicable to systems having electron-rich aromatic rings, leading to high specific activity radiopharmaceuticals. Furthermore, the suitably protected dihydroxynitrobenzaldehyde 1 may serve as a useful synthetic precursor for the radiosynthesis of other complex {sup 18}F-labeled radiotracers.

  1. Biochemical characterization of a thermophilic β-mannanase from Talaromyces leycettanus JCM12802 with high specific activity.

    PubMed

    Wang, Caihong; Luo, Huiying; Niu, Canfang; Shi, Pengjun; Huang, Huoqing; Meng, Kun; Bai, Yingguo; Wang, Kun; Hua, Huifang; Yao, Bin

    2015-02-01

    Thermophilic β-mannanases are of increasing importance for wide industrial applications. In the current study, gene cloning, functional expression in Pichia pastoris, and characterization of a thermophilic β-mannanase (Man5A) from thermophilic Talaromyces leycettanus JCM12802 are reported. Deduced Man5A exhibits the highest identity with a putative β-mannanase from Talaromyces stipitatus ATCC10500 (70.3 %) and is composed of an N-terminal signal peptide, a fungal-type carbohydrate-binding module (CBM) of family 1, and a catalytic domain of glycosyl hydrolase (GH) family 5 at the C-terminus. Two recombinant proteins with different glycosylation levels, termed Man5A1 (72 kDa) and Man5A2 (60 kDa), were identified after purification. Both enzymes were thermophilic, exhibiting optimal activity at 85-90 °C, and were highly stable at 70 °C. Man5A1 and Man5A2 had a pH optimum of 4.5 and 4.0, respectively, and were highly stable over the broad pH range of 3.0-10.0. Most metal ions and sodium dodecyl sulfate (SDS) had no effect on the enzymatic activities. Man5A1 and Man5A2 exhibited high specific activity (2,160 and 1,800 U/mg, respectively) when using locust bean gum as the substrate. The CBM1 and two key residues D191 and R286 were found to affect Man5A thermostability. Man5A displays a classical four-site-binding mode, hydrolyzing mannooligosaccharides into smaller units, galactomannan into mannose and mannobiose, and glucomanman into mannose, mannobiose, and mannopentaose, respectively. All these properties make Man5A a good candidate for extensive applications in the bioconversion, pulp bleaching, textile, food, and feed industries. PMID:25104029

  2. Development of a high specific activity radioligand, /sup 125/I-LSD, and its application to the study of serotonin receptors

    SciTech Connect

    Kadan, M.J.

    1987-01-01

    /sup 125/I-Labeled receptor ligands can be synthesized with specific activities exceeding 2000 Ci/mmol, making them nearly 70-fold more sensitive in receptor site assays than (mono) tritiated ligands. We have synthesized and characterized /sup 125/I-lysergic acid diethylamide (/sup 125/I-LSD), the first radioiodinated ligand for serotonin receptor studies. The introduction of /sup 125/I at the 2 position of LSD increased both the affinity and selectivity of this compound for serotonin 5-HT/sub 2/ receptors in rat cortex. The high specific activity of /sup 125/I-LSD and its high ratio of specific to nonspecific binding make this ligand especially useful for autoradiographic studies of serotonin receptor distribution. We have found that /sup 125/I-LSD binds with high affinity to a class of serotonin receptors in the CNS of the marine mollusk Aplysia californica.

  3. Production of medical radioisotopes with high specific activity in photonuclear reactions with γ-beams of high intensity and large brilliance

    NASA Astrophysics Data System (ADS)

    Habs, D.; Köster, U.

    2011-05-01

    We study the production of radioisotopes for nuclear medicine in ( γ, xn+ yp) photonuclear reactions or ( γ, γ') photoexcitation reactions with high-flux [(1013-1015) γ/s], small diameter ˜(100 μm)2 and small bandwidth (Δ E/ E≈10-3-10-4) γ beams produced by Compton back-scattering of laser light from relativistic brilliant electron beams. We compare them to (ion, xn+ yp) reactions with (ion = p,d, α) from particle accelerators like cyclotrons and (n, γ) or (n,f) reactions from nuclear reactors. For photonuclear reactions with a narrow γ-beam the energy deposition in the target can be managed by using a stack of thin target foils or wires, hence avoiding direct stopping of the Compton and pair electrons (positrons). However, for ions with a strong atomic stopping only a fraction of less than 10-2 leads to nuclear reactions resulting in a target heating, which is at least 105 times larger per produced radioactive ion and often limits the achievable activity. In photonuclear reactions the well defined initial excitation energy of the compound nucleus leads to a small number of reaction channels and enables new combinations of target isotope and final radioisotope. The narrow bandwidth γ excitation may make use of the fine structure of the Pygmy Dipole Resonance (PDR) or fluctuations in γ-width leading to increased cross sections. Within a rather short period compared to the isotopic half-life, a target area of the order of (100 μm)2 can be highly transmuted, resulting in a very high specific activity. ( γ, γ') isomer production via specially selected γ cascades allows to produce high specific activity in multiple excitations, where no back-pumping of the isomer to the ground state occurs. We discuss in detail many specific radioisotopes for diagnostics and therapy applications. Photonuclear reactions with γ-beams allow to produce certain radioisotopes, e.g. 47Sc, 44Ti, 67Cu, 103Pd, 117 m Sn, 169Er, 195 m Pt or 225Ac, with higher specific activity

  4. Cloning and characterization of a modular GH5 β-1,4-mannanase with high specific activity from the fibrolytic bacterium Cellulosimicrobium sp. strain HY-13.

    PubMed

    Kim, Do Young; Ham, Su-Jin; Lee, Hyun Ju; Cho, Han-Young; Kim, Ji-Hoon; Kim, Yi-Joon; Shin, Dong-Ha; Rhee, Young Ha; Son, Kwang-Hee; Park, Ho-Yong

    2011-10-01

    The gene (1272-bp) encoding a β-1,4-mannanase from a gut bacterium of Eisenia fetida, Cellulosimicrobium sp. strain HY-13 was cloned and expressed in Escherichia coli. The recombinant β-1,4-mannanase (rManH) was approximately 44.0 kDa and has a catalytic GH5 domain that is 65% identical to that of the Micromonospora sp. β-1,4-mannosidase. The enzyme exhibited the highest catalytic activity toward mannans at 50 °C and pH 6.0. rManH displayed a high specific activity of 14,711 and 8498 IU mg⁻¹ towards ivory nut mannan and locust bean gum, respectively; however it could not degrade the structurally unrelated polysaccharides, mannobiose, or p-nitrophenyl sugar derivatives. rManH was strongly bound to ivory nut mannan, Avicel, chitosan, and chitin but did not attach to curdlan, insoluble oat spelt xylan, lignin, or poly(3-hydroxybutyrate). The superior biocatalytic properties of rManH suggest that the enzyme can be exploited as an effective additive in the animal feed industry. PMID:21767948

  5. Identification of lipase encoding genes from Antarctic seawater bacteria using degenerate primers: expression of a cold-active lipase with high specific activity.

    PubMed

    Parra, Loreto P; Espina, Giannina; Devia, Javier; Salazar, Oriana; Andrews, Barbara; Asenjo, Juan A

    2015-01-01

    Cold-active enzymes are valuable catalysts showing high activity at low and moderate temperatures and low thermostability. Among cold-active enzymes, lipases offer a great potential in detergent, cosmetic, biofuel and food or feed industries. In this paper we describe the identification of novel lipase coding genes and the expression of a lipase with high activity at low temperatures. The genomic DNA from Antarctic seawater bacteria showing lipolytic activity at 4°C was used to amplify five DNA fragments that partially encode novel lipases using specifically designed COnsensus-DEgenerate Hybrid Oligonucleotide Primers (CODEHOP). All the fragments were found to have a high identity with an α/β-hydrolase domain-containing protein identified by the sequencing of the complete genome of Shewanella frigidimarina NCIMB 400. The complete sequence of one of the lipase-coding gene fragments, lipE13, was obtained by genome walking. Considering that the other fragments had a high identity to the putative lipase from S. frigidimarina NCIMB 400, the complete lipase genes were amplified using oligonucleotide primers designed based on the 5' and 3' regions of the coding sequence of the related protein. This strategy allowed the amplification of 3 lipase-encoding genes of which one was expressed in the periplasm using the Escherichia coli BL21(DE3)/pET-22b(+) expression system. The recombinant protein was obtained with activity toward p-nitrophenyl caproate showing a high specific activity between 15 and 25°C. PMID:25435506

  6. Cyclotron production of high specific activity 55Co and in vivo evaluation of the stability of 55Co metal-chelate-peptide complexes

    PubMed Central

    Mastren, Tara; Marquez, Bernadette V.; Sultan, Deborah E.; Bollinger, Elizabeth; Eisenbeis, Paul; Voller, Tom; Lapi, Suzanne E.

    2016-01-01

    This work describes the production of high-specific activity 55Co and the evaluation of the stability of 55Co-metal-chelate-peptide complexes in vivo. 55Co was produced via the 58Ni(p,α)55Co reaction and purified using anion exchange chromatography with an average recovery of 92% and an average specific activity of 1.96GBq/µmol. 55Co-DO3A and 55Co-NO2A peptide complexes were radiolabelled at 3.7MBq/µg and injected into HCT-116 tumor xenografted mice. PET imaging and biodistribution studies were performed at 24 and 48 hours post injection and compared with that of 55CoCl2. Both 55Co-metal-chelate complexes demonstrated good in vivo stability by reducing the radiotracers’ uptake in the liver by 6-fold at 24 with ~1% ID/g and at 48 hours with ~0.5% ID/g, and reducing uptake in the heart by 4-fold at 24 hours with ~0.7% ID/g and 7-fold at 48 hours with ~0.35% ID/g. These results support the use of 55Co as a promising new radiotracer for Positron Emission Tomography (PET) imaging of cancer and other diseases. PMID:26505224

  7. 16. cap alpha. -(/sup 77/Br)bromoestradiol-17. beta. : a high specific-activity, gamma-emitting tracer with uptake in rat uterus and induced mammary tumors

    SciTech Connect

    Katzenellenbogen, J.A.; Senderoff, S.G.; McElvany, K.D.; O'Brien, H.A. Jr.; Welch, M.J.

    1981-01-01

    16..cap alpha..-(/sup 77/Br)bromoestradiol-17..beta.. (compound 1) has been synthesized by radiobromination of estrone enoldiacetate. Tissue uptake studies performed 1 hr after administration of compound 1 to immature or mature female rats showed uterus-to-blood ratios of 13, with nontarget tissue-to-blood ratios ranging from 0.6 to 2. Co-administration of unlabeled estradiol caused a selective depression in the uterine uptake with no effect on nontarget tissue uptake. In adult animals bearing adenocarcinomas induced by DMBA (7,12-dimethylbenz(a)anthracene), tumor-to-blood ratios of 6.3 were obtained, this uptake also being depressed in animals treated with unlabeled estradiol. The studies demonstrate that compound 1 has suitable binding properties and sufficiently high specific activity so that its uptake in estrogen target tissues in vivo is mediated primarily by the estrogen receptor. Furthermore, they suggest that this compound may be suitable for imaging human breast tumors that contain estrogen receptors.

  8. Cyclotron Production of High-Specific Activity 55Co and In Vivo Evaluation of the Stability of 55Co Metal-Chelate-Peptide Complexes.

    PubMed

    Mastren, Tara; Marquez, Bernadette V; Sultan, Deborah E; Bollinger, Elizabeth; Eisenbeis, Paul; Voller, Tom; Lapi, Suzanne E

    2015-01-01

    This work describes the production of high-specific activity 55Co and the evaluation of the stability of 55Co-metal-chelate-peptide complexes in vivo. 55Co was produced via the 58Ni(p,α)55Co reaction and purified using anion exchange chromatography with an average recovery of 92% and an average specific activity of 1.96 GBq/μmol. 55Co-DO3A and 55Co-NO2A peptide complexes were radiolabeled at 3.7 MBq/μg and injected into HCT-116 tumor xenografted mice. Positron emission tomography (PET) and biodistribution studies were performed at 24 and 48 hours postinjection and compared to those of 55CoCl2. Both 55Co-metal-chelate complexes demonstrated good in vivo stability by reducing the radiotracers' uptake in the liver by sixfold at 24 hours with ~ 1% ID/g and at 48 hours with ~ 0.5% ID/g and reducing uptake in the heart by fourfold at 24 hours with ~ 0.7% ID/g and sevenfold at 48 hours with ~ 0.35% ID/g. These results support the use of 55Co as a promising new radiotracer for PET imaging of cancer and other diseases. PMID:26505224

  9. Feasibility of Multiple Examinations Using 68Ga-Labelled Collagelin Analogues: Organ Distribution in Rat for Extrapolation to Human Organ and Whole-Body Radiation Dosimetry

    PubMed Central

    Velikyan, Irina; Rosenström, Ulrika; Bulenga, Thomas N.; Eriksson, Olof; Antoni, Gunnar

    2016-01-01

    Objectives: Fibrosis is involved in many chronic diseases. It affects the functionality of vital organs, such as liver, lung, heart and kidney. Two novel imaging agents for positron emission tomography (PET) imaging of fibrosis have previously pre-clinically demonstrated promising target binding and organ distribution characteristics. However, the relevant disease monitoring in the clinical setup would require multiple repetitive examinations per year. Thus, it is of paramount importance to investigate the absorbed doses and total effective doses and thus, the potential maximum number of examinations per year. Methods: Two cyclic peptide (c[CPGRVMHGLHLGDDEGPC]) analogues coupled via an ethylene glycol linker (EG2) to either 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid (NO2A-Col) or 4-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazacyclononan-1-yl)-5-(tert-butoxy)-5-oxopentanoic acid (NODAGA-Col) were labelled with 68Ga. The resulting agents, [68Ga]Ga-NO2A-Col and [68Ga]Ga-NODAGA-Col, were administered in the tail vein of male and female Sprague–Dawley rats (N = 24). An ex vivo organ distribution study was performed at the 5-, 10-, 20-, 40-, 60- and 120-min time points. The resulting data were extrapolated for the estimation of human organ and total body absorbed and total effective doses using Organ Level Internal Dose Assessment Code software (OLINDA/EXM 1.1) assuming a similar organ distribution pattern between the species. Time-integrated radioactivity in each organ was calculated by trapezoidal integration followed by a single-exponential fit to the data points extrapolated to infinity. The resulting values were used for the residence time calculation. Results: Ex vivo organ distribution data revealed fast blood clearance and washout from most of the organs. Although the highest organ absorbed dose was found for kidneys (0.1 mGy/MBq), this organ was not the dose-limiting one and would allow for the administration of over 1460 MBq per year for both [68Ga]Ga-NO2A-Col and [68Ga]Ga-NODAGA-Col. The total effective dose was the limiting parameter with 0.0155/0.0156 (female/male) mSv/MBq and 0.0164/0.0158 (female/male) mSv/MBq, respectively, for [68Ga]Ga-NO2A-Col and [68Ga]Ga-NODAGA-Col. This corresponded to the total amount of radioactivity that could be administered per year of 643 and 621 MBq before reaching the annual limit of 10 mSv. Thus, up to six examinations would be possible. The residence time and organ absorbed doses in liver and spleen were higher for [68Ga]Ga-NODAGA-Col as compared to [68Ga]Ga-NO2A-Col. Conclusion: The limiting parameter for the administered dose was the total effective dose that would allow for at least six examinations per year that might be sufficient for adequate disease monitoring in longitudinal studies and a routine clinical setup. PMID:27275825

  10. Synthesis and in Vivo Biological Evaluation of (68)Ga-Labeled Carbonic Anhydrase IX Targeting Small Molecules for Positron Emission Tomography.

    PubMed

    Sneddon, Deborah; Niemans, Raymon; Bauwens, Matthias; Yaromina, Ala; van Kuijk, Simon J A; Lieuwes, Natasja G; Biemans, Rianne; Pooters, Ivo; Pellegrini, Paul A; Lengkeek, Nigel A; Greguric, Ivan; Tonissen, Kathryn F; Supuran, Claudiu T; Lambin, Philippe; Dubois, Ludwig; Poulsen, Sally-Ann

    2016-07-14

    Tumor hypoxia contributes resistance to chemo- and radiotherapy, while oxygenated tumors are sensitive to these treatments. The indirect detection of hypoxic tumors is possible by targeting carbonic anhydrase IX (CA IX), an enzyme overexpressed in hypoxic tumors, with sulfonamide-based imaging agents. In this study, we present the design and synthesis of novel gallium-radiolabeled small-molecule sulfonamides targeting CA IX. The compounds display favorable in vivo pharmacokinetics and stability. We demonstrate that our lead compound, [(68)Ga]-2, discriminates CA IX-expressing tumors in vivo in a mouse xenograft model using positron emission tomography (PET). This compound shows specific tumor accumulation and low uptake in blood and clears intact to the urine. These findings were reproduced in a second study using PET/computed tomography. Small molecules investigated to date utilizing (68)Ga for preclinical CA IX imaging are scarce, and this is one of the first effective (68)Ga compounds reported for PET imaging of CA IX. PMID:27322137

  11. 68Ga-Labeled Anti-Prostate-Specific Membrane Antigen Peptide as Marker for Androgen Deprivation Therapy Response in Prostate Cancer.

    PubMed

    Schlenkhoff, Carl Diedrich; Gaertner, Florian; Essler, Markus; Hauser, Stefan; Ahmadzadehfar, Hojjat

    2016-05-01

    Prostate cancer was diagnosed in a 71-year-old man with an elevated prostate-specific antigen. The CT of the abdomen showed multiple para-aortal lymph nodes, and thus, a Ga anti-prostate-specific membrane antigen (PSMA-11) PET/CT was initiated, which showed, aside from the prostate cancer and multiple iliacal and para-aortal lymph node metastases, an increased tracer uptake in a lymph node left cervical. According to this advanced disease, a palliative therapy with GnRH agonist was initiated. A second PSMA-11 PET/CT was performed 4 months later, which showed a very good response; thus, additional radiation of the pelvis and the draining lymphatic system was performed. PMID:26859213

  12. Efficient one-step radiolabeling of monoclonal antibodies to high specific activity with Actinium-225 for alpha-particle radioimmunotherapy of cancer

    PubMed Central

    Maguire, William F.; McDevitt, Michael R.; Smith-Jones, Peter M.; Scheinberg, David A.

    2015-01-01

    Targeted alpha-particle radiation using the radioisotope 225Actinium (225Ac) is a promising form of therapy for various types of cancer. Historical obstacles to the use of 225Ac have been the difficulty in finding suitable chelators to stably attach it to targeting vehicles such as peptides and monoclonal antibodies, the low specific activities of the products, and the lack of cost-effective radiolabeling procedures. We initially solved the first problem with a procedure involving two chemical steps that has been used as a standard in preclinical and clinical studies. However, this procedure involves the loss of 90% of the input 225Ac. A more efficient, economical process is needed to facilitate the more widespread use of 225Ac. Methods We conjugated representative antibodies with two forms of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), as well as other chelators as controls. We developed conditions to radiolabel these constructs in one chemical step and characterized their stability, immunoreactivity, biodistribution, and therapeutic efficacy in healthy and tumor-bearing mice. Results DOTA- antibody constructs were labeled to a wide range of specific activities in one chemical step at 37 °C. Radiochemical yields were approximately 10-fold higher and specific activities were up to 30-fold higher than with the previous approach. The products retained immunoreactivity and were stable to serum challenge in vitro and in mice. Labeling kinetics of DOTA- antibody constructs linked through a benzyl isothiocyanate linkage were more favorable than those linked through a N-hydroxysuccinimide linkage. Tissue distribution was similar but not identical between the constructs. The constructs produced specific therapeutic responses in a mouse model of acute myeloid leukemia. Conclusion We have characterized an efficient, one-step radiolabeling method that produces stable, therapeutically active conjugates of antibodies with 225Ac at high specific activity

  13. Deuteron irradiation of W and WO3 for production of high specific activity (186)Re: Challenges associated with thick target preparation.

    PubMed

    Balkin, Ethan R; Gagnon, Katherine; Strong, Kevin T; Smith, Bennett E; Dorman, Eric F; Emery, Robert C; Pauzauskie, Peter J; Fassbender, Michael E; Cutler, Cathy S; Ketring, Alan R; Jurisson, Silvia S; Wilbur, D Scott

    2016-09-01

    This investigation evaluated target fabrication and beam parameters for scale-up production of high specific activity (186)Re using deuteron irradiation of enriched (186)W via the (186)W(d,2n)(186)Re reaction. Thick W and WO3 targets were prepared, characterized and evaluated in deuteron irradiations. Full-thickness targets, as determined using SRIM, were prepared by uniaxially pressing powdered natural abundance W and WO3, or 96.86% enriched (186)W, into Al target supports. Alternatively, thick targets were prepared by pressing (186)W between two layers of graphite powder or by placing pre-sintered (1105°C, 12h) natural abundance WO3 pellets into an Al target support. Assessments of structural integrity were made on each target prepared. Prior to irradiation, material composition analyses were conducted using SEM, XRD, and Raman spectroscopy. Within a minimum of 24h post irradiation, gamma-ray spectroscopy was performed on all targets to assess production yields and radionuclidic byproducts. Problems were encountered with the structural integrity of some pressed W and WO3 pellets before and during irradiation, and target material characterization results could be correlated with the structural integrity of the pressed target pellets. Under the conditions studied, the findings suggest that all WO3 targets prepared and studied were unacceptable. By contrast, (186)W metal was found to be a viable target material for (186)Re production. Thick targets prepared with powdered (186)W pressed between layers of graphite provided a particularly robust target configuration. PMID:27423020

  14. Production of high specific activity (195m) Pt-cisplatinum at South African Nuclear Energy Corporation for Phase 0 clinical trials in healthy individual subjects.

    PubMed

    Zeevaart, Jan Rijn; Wagener, Judith; Marjanovic-Painter, Biljana; Sathekge, Mike; Soni, Nischal; Zinn, Christa; Perkins, Gary; Smith, Suzanne V

    2013-01-01

    Platinum agents continue to be the main chemotherapeutic agents used in the first-line and second-line treatments of cancer patients. It is important to fully understand the biological profile of these compounds in order to optimize the dose given to each patient. In a joint project with the Australian Nuclear Science and Technology Organisation and the Nuclear Medicine Department at Steve Biko Academic Hospital, South African Nuclear Energy Corporation synthesized and supplied (195m) Pt-cisplatinum (commonly referred to as cisplatin) for a clinical pilot study on healthy volunteers. Enriched (194) PtCl2 was prepared by digestion of enriched (194) Pt metal (>95%) followed by thermal decomposition over a 3 h period. The (194) PtCl2 was then placed in a quartz ampoule, was irradiated in SAFARI-1 up to 200 h, then decay cooled for a minimum of 34 h prior to synthesis of final product. (195m) Pt(NH3 )2 I2 , formed with the addition of KI and NH4 OH, was converted to the diaqua species [(195m) Pt(NH3 )2 (H2 O)2 ](2+) by reaction with AgNO3 . The conversion to (195m) Pt-cisplatinum was completed by the addition of concentrated HCl. The final product yield was 51.7% ± 5.2% (n = 5). The chemical and radionuclidic purity in each case was >95%. The use of a high flux reactor position affords a higher specific activity product (15.9 ± 2.5 MBq/mg at end of synthesis) than previously found (5 MBq/mg). Volunteers received between 108 and 126 MBq of radioactivity, which is equivalent to 6.8-10.0 mg of carrier cisplatinum. Such high specific activities afforded a significant reduction (~50%) in the chemical dose of a carrier cisplatinum, which represents less than 10% of a typical chemotherapeutic dose given to patients. A good manufacturing practice GMP compliant product was produced and was administered to 10 healthy volunteers as part of an ethically approved Phase 0 clinical trial. The majority of the injected activity 27.5% ± 5.8% was excreted

  15. Preparation of high specific activity technetium-96

    DOEpatents

    Mausner, Leonard F.; Srivastava, Suresh C.; Prach, Thomas

    1992-01-01

    The present invention relates to a method of producing Tc-96 from the proton irradiation of a rhodium target and a technique for isolating under remote hot cell conditions the Tc-96 from the proton irradiated target.

  16. High specific activity platinum-195m

    DOEpatents

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-10-12

    A new composition of matter includes .sup.195m Pt characterized by a specific activity of at least 30 mCi/mg Pt, generally made by method that includes the steps of: exposing .sup.193 Ir to a flux of neutrons sufficient to convert a portion of the .sup.193 Ir to .sup.195m Pt to form an irradiated material; dissolving the irradiated material to form an intermediate solution comprising Ir and Pt; and separating the Pt from the Ir by cation exchange chromatography to produce .sup.195m Pt.

  17. Characterization of high specific activity (16 alpha-123I)Iodo-17 beta-estradiol as an estrogen receptor-specific radioligand capable of imaging estrogen receptor-positive tumors

    SciTech Connect

    Pavlik, E.J.; Nelson, K.; Gallion, H.H.; van Nagell, J.R. Jr.; Donaldson, E.S.; Shih, W.J.; Spicer, J.A.; Preston, D.F.; Baranczuk, R.J.; Kenady, D.E. )

    1990-12-15

    16 alpha-(123I)Iodo-17 beta-estradiol (16 alpha-(123I)E2) has been characterized for use as a selective radioligand for estrogen receptor (ERc) that is capable of generating in situ images of ERc-positive tumors. High specific activity 16 alpha-(123I)E2 (7,500-10,000 Ci/mmol) was used in all determinations. Radiochemical purity was determined by thin layer chromatography, and the selectivity of radioligand for ERc was evaluated using size exclusion high performance liquid chromatography on ERc prepared from rodent uteri. Efficiencies of radioidination approaching 100% were achieved, and excellent receptor selectivity was obtained even when the efficiency of radioiodination was as low as 10%. Low radiochemical purity was always associated with poor selectivity for ERc. No new radioligand species was generated during the course of radiodecay; however, reduced binding over time, even when increased activity was used to compensate for radiodecay, indicated that the formation of a radioinert competitor does occur. 16 alpha-(123I)E2 demonstrated stable, high affinity binding to ERc and was concentrated by ERc-positive tissues. After injecting 16 alpha-(123I)E2 in vivo, images of ERc-containing tissues were obtained, including rabbit reproductive tract and dimethylbenzanthracene-induced tumors. The demonstrations of ERc selectivity and image formation both indicate that 16 alpha-(123I)E2 should have promise as a useful new radiopharmaceutical for imaging ERc-positive cancers.

  18. 16 alpha-(/sup 77/Br)bromoestradiol-17 beta: a high specific-activity, gamma-emitting tracer with uptake in rat uterus and uterus and induced mammary tumors

    SciTech Connect

    Katzenellenbogen, J.A.; Senderoff, S.G.; McElvany, K.D.; O'Brien, H.A. Jr.; Welch, M.J.

    1981-01-01

    16 alpha-(77Br)bromoestradiol-17 beta (Compound 1) has been synthesized by radiobromination of estrone enoldiacetate. Tissue uptake studies performed 1 h after administration of Compound 1 to immature or mature female rats showed uterus-to-blood ratios of 13, with nontarget issue-to-blood ratios ranging from 0.6 to 2. Co-administration of unlabelled estradiol caused a selective depression in the uterine uptake with no effect on nontarget tissue uptake. In adult animals bearing adenocarcinomas induced by DMBA (7,12-dimethylbenz(a)anthracene), tumor-to-blood ratios of 6.3 were obtained, this uptake also being depressed in animals treated with unlabeled estradiol. The studies demonstrate that Compound 1 has suitable binding properties and sufficiently high specific activity so that its uptake in estrogen target tissues in vivo is mediated primarily by the estrogen receptor. Furthermore, they suggest that this compound may be suitable for imaging human breast tumors that contain estrogen receptors.

  19. Integrin αvβ3 as a Promising Target to Image Neoangiogenesis Using In-House Generator-Produced Positron Emitter (68)Ga-Labeled DOTA-Arginine-Glycine-Aspartic Acid (RGD) Ligand.

    PubMed

    Vatsa, Rakhee; Bhusari, Priya; Kumar, Sunil; Chakraborty, Sudipta; Dash, Ashutosh; Singh, Gurpreet; Dhawan, Devinder Kumar; Shukla, Jaya; Mittal, Bhagwant Rai

    2015-06-01

    For the growth and spread of a tumor beyond 2 mm, angiogenesis plays a crucial role, and association of various integrins with angiogenesis is evidential. The aim of the study was radiolabeling of DOTA-chelated RGD (arginine-glycine-aspartic acid) peptide with (68)Ga for PET imaging in locally advanced breast carcinoma. DOTA-RGD was incubated with (68)GaCl3, eluted in 0.05 m HCl. Elution volume, peptide amount, and reaction pH were studied. Radio-ITLC, gas chromatography, endotoxin, and sterility testing were performed. Serial (n=3) and whole-body (n=2) PET/CT imaging was done on patients post i.v. injection of 111-185 MBq of (68)Ga-DOTA-RGD. Maximum radiolabeling yield was achieved with 3 mL elution volume of 15-20 μg peptide at pH 3.5-4.0 with 10 minutes of incubation at 95°C. Product samples were sterile having 99.5% radiochemical purity with residual ethanol content and endotoxins in injectable limits. Intense radiotracer uptake was noticed in the tumor with SUVmax 15.3 at 45 minutes in serial images. Physiological radiotracer uptake was seen in the liver, spleen, ventricles, and thyroid with excretion through the kidneys. The authors concluded that (68)Ga-DOTA-RGD has the potential for imaging α,vβ3 integrin-expressing tumors. PMID:26083951

  20. Steps toward high specific activity labeling of biomolecules for therapeutic application: preparation of precursor [(188)Re(H(2)O)(3)(CO)(3)](+) and synthesis of tailor-made bifunctional ligand systems.

    PubMed

    Schibli, Roger; Schwarzbach, Rolf; Alberto, Roger; Ortner, Kirstin; Schmalle, Helmut; Dumas, Cécile; Egli, André; Schubiger, P August

    2002-01-01

    organometallic labeling of biomolecules with unprecedented high specific activities. PMID:12121130

  1. Inhibition of Plasma Kallikrein by a Highly Specific Active Site Blocking Antibody

    PubMed Central

    Kenniston, Jon A.; Faucette, Ryan R.; Martik, Diana; Comeau, Stephen R.; Lindberg, Allison P.; Kopacz, Kris J.; Conley, Gregory P.; Chen, Jie; Viswanathan, Malini; Kastrapeli, Niksa; Cosic, Janja; Mason, Shauna; DiLeo, Mike; Abendroth, Jan; Kuzmic, Petr; Ladner, Robert C.; Edwards, Thomas E.; TenHoor, Christopher; Adelman, Burt A.; Nixon, Andrew E.; Sexton, Daniel J.

    2014-01-01

    Plasma kallikrein (pKal) proteolytically cleaves high molecular weight kininogen to generate the potent vasodilator and the pro-inflammatory peptide, bradykinin. pKal activity is tightly regulated in healthy individuals by the serpin C1-inhibitor, but individuals with hereditary angioedema (HAE) are deficient in C1-inhibitor and consequently exhibit excessive bradykinin generation that in turn causes debilitating and potentially fatal swelling attacks. To develop a potential therapeutic agent for HAE and other pKal-mediated disorders, we used phage display to discover a fully human IgG1 monoclonal antibody (DX-2930) against pKal. In vitro experiments demonstrated that DX-2930 potently inhibits active pKal (Ki = 0.120 ± 0.005 nm) but does not target either the zymogen (prekallikrein) or any other serine protease tested. These findings are supported by a 2.1-Å resolution crystal structure of pKal complexed to a DX-2930 Fab construct, which establishes that the pKal active site is fully occluded by the antibody. DX-2930 injected subcutaneously into cynomolgus monkeys exhibited a long half-life (t½ ∼12.5 days) and blocked high molecular weight kininogen proteolysis in activated plasma in a dose- and time-dependent manner. Furthermore, subcutaneous DX-2930 reduced carrageenan-induced paw edema in rats. A potent and long acting inhibitor of pKal activity could be an effective treatment option for pKal-mediated diseases, such as HAE. PMID:24970892

  2. Enrichment and isolation of a ruminal bacterium with a very high specific activity of ammonia production.

    PubMed Central

    Russell, J B; Strobel, H J; Chen, G J

    1988-01-01

    When mixed ruminal bacteria were inoculated into semicontinuous cultures (25% transfer every other day) containing lactate, dulcitol, pectin, or xylose and Trypticase (1 g/liter) as the sole nitrogen source, the specific activity of ammonia production increased. The greatest enrichment was observed with lactate and xylose, and in these cases the specific rate of ammonia production was eightfold higher than that of the ruminal fluid control (approximately 35 nmol of ammonia per mg of protein per min). Isolates with different morphologies were obtained from each of the enrichments, but in no case did the specific activity of any isolate exceed that of the mixed ruminal bacteria. If Trypticase (15 g/liter) was used as the only energy and nitrogen source, there was an even greater increase in ammonia production, and two monensin-sensitive bacteria, a Peptostreptococcus species and a Clostridium species, were obtained. The Peptostreptococcus species was unable to grow on any of 25 carbohydrate or carbohydrate derivatives tested; but the Clostridium species was able to use glucose, maltose, fructose, cellobiose, trehalose, sorbitol, and salicin as energy sources. Neither organism was able to grow in the absence of an amino acid source, but growth rates on Trypticase were greater than 0.35/h. The specific activities of ammonia production were 346 and 427 nmol/mg of protein per min for strains of Peptostreptococcus and Clostridium, respectively. Megasphaera elsdenii and Bacteroides ruminicola, previously isolated ruminal ammonia producers, had specific activities of only 11 and 19 nmol of ammonia per mg of protein per min, respectively. The most probable number of Clostridium species in ruminal fluid was less than 10(3)/ml, but the Peptostreptococcus species was present at 10(8)/ml.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3377500

  3. Target design considerations for high specific activity [{sup 11}C]O{sub 2}

    SciTech Connect

    Ferrieri, R.A.; Alexoff, D.L.; Schlyer, D.J.; McDonald, K.; Wolf, A.P.

    1993-12-31

    In the routine preparation of {sup 11}C-labeled compounds through N-[{sup 11}C]-methylation using [{sup 11}C]H{sub 3}I, total masses are always higher than synthesis mass contribution, suggesting that the target system contributes carrier carbon to the final product mass. This conclusion prompted this evaluation of target materials and target design for [{sup 11}C]O{sub 2} production. Ultimately, one is faced with the sprospect of compromising between [{sup 11}C]O{sub 2} specific activity and the amount that can be extracted from the target after a reasonable irradiation time.

  4. The diageotropica mutant of tomato lacks high specific activity auxin sites

    SciTech Connect

    Hicks, G.R.; Lomax, T.L. ); Rayle, D.L. )

    1989-04-01

    Tomato (Lycopersicum esculentum, Mill) plants homozygous for the single gene diageotropica (dgt) mutation have reduced shoot growth, abnormal vascular tissue, altered leaf morphology, and lack of lateral root branching. These and other morphological and physiological abnormalities suggest that dgt plants are unable to respond to the plant growth hormone auxin (indole-3-acetic acid, IAA). The photoaffinity auxin analogue {sup 3}H-5N{sub 3}-IAA specifically labels a polypeptide doublet of 40 ad 42 kD in membrane preparations from stems of the parental variety VFN8, but not from stems of dgt. In elongation tests, excised dgt roots respond in the same manner to IAA an VFN8 roots. These data suggest that the two polypeptides are part of a physiologically important auxin receptor system which is altered in a tissue-specific manner in the mutant.

  5. The diageotropica mutant of tomato lacks high specific activity auxin binding sites

    NASA Technical Reports Server (NTRS)

    Hicks, G. R.; Rayle, D. L.; Lomax, T. L.

    1989-01-01

    Tomato plants homozygous for the diageotropica (dgt) mutation exhibit morphological and physiological abnormalities which suggest that they are unable to respond to the plant growth hormone auxin (indole-3-acetic acid). The photoaffinity auxin analog [3H]5N3-IAA specifically labels a polypeptide doublet of 40 and 42 kilodaltons in membrane preparations from stems of the parental variety, VFN8, but not from stems of plants containing the dgt mutation. In roots of the mutant plants, however, labeling is indistinguishable from that in VFN8. These data suggest that the two polypeptides are part of a physiologically important auxin receptor system, which is altered in a tissue-specific manner in the mutant.

  6. Radiosynthesis and pharmacokinetics of high specific activity /sup 75,77/Br-bromperidol, a potent butyrophenone neuroleptic

    SciTech Connect

    Moerlein, S.M.; Stocklin, G.

    1984-01-01

    Bromperidol, 4-(4-(4-bromophenyl)-4-hydroxypiperidino)-4'- fluorobutyrophenone, is a potent neuroleptic which has found clinical use in the treatment of schizophrenia. Of the major dopaminergic receptor-binding ligands, bromperidol has the greatest specificity for binding to cerebral dopamine receptors (K/sub i/ = 3.7 nM) relative to competitive cerebral serotonin (K/sub i/ = 26 nM), ..cap alpha..-adrenergic (K/sub i/ = 100 nM) or histamine (K/sub i/ = 700 nM) receptors. The authors have therefore prepared bromperidol labelled with no-carrier-added (n.c.a.) /sup 75/Br (t/sub 1/2/ = 1.6 hr ..beta../sup +/) or /sup 77/Br (t/sub 1/2/ = 52 hr EC) for evaluation as a radiopharmaceutical for mapping cerebral dopamine receptor areas with PECT technology, as well as for non-invasive pharmacodynamic studies in man with conventional nuclear medicine equipment. 4-(4-(4-trimethylstannylphenyl)-4-hydroxypiperidino)-4'- fluorobutyrophenone, TMSn-P, was synthesized in 40% chemical yield by reaction of trimethylstannyl sodium with bromperidol. TMSn-P was purified by preparative HPLC and characterized by /sup 1/H-NMR and GC-MS. TMSn-P was radiobrominated in methanol using n.c.a. /sup 75/Br/sup -/ or /sup 77/Br/sup -/ and dichloramine-T as oxidizing agent. Product /sup 75,77/Br-bromperidol was separated from impurities, including chlorinated side-product halo-peridol, using HPLC (RP-18; MeOH/H/sub 2/O/Et/sub 3/N = 70/30/0.3). For a reaction time of 5 minutes, and an overall radiopharmaceutical production time of 30 minutes, /sup 75,77/Br-bromperidol was obtained in physiological saline solution with 40% radiochemical yield and a specific activity > 10,000 Ci/mmole. The pharmacokinetics in rodents and PECT studies in primates using /sup 75,77/Br-bromperidol are compared with that of previously-reported /sup 75,77/Br-brombenperidol.

  7. Overexpression and characterization of a glucose-tolerant β-glucosidase from T. aotearoense with high specific activity for cellobiose.

    PubMed

    Yang, Fang; Yang, Xiaofeng; Li, Zhe; Du, Chenyu; Wang, Jufang; Li, Shuang

    2015-11-01

    Thermoanaerobacterium aotearoense P8G3#4 produced β-glucosidase (BGL) intracellularly when grown in liquid culture on cellobiose. The gene bgl, encoding β-glucosidase, was cloned and sequenced. Analysis revealed that the bgl contained an open reading frame of 1314 bp encoding a protein of 446 amino acid residues, and the product belonged to the glycoside hydrolase family 1 with the canonical glycoside hydrolase family 1 (GH1) (β/α)8 TIM barrel fold. Expression of pET-bgl together with a chaperone gene cloned in vector pGro7 in Escherichia coli dramatically enhanced the crude enzyme activity to a specific activity of 256.3 U/mg wet cells, which resulted in a 9.2-fold increase of that obtained from the expression without any chaperones. The purified BGL exhibited relatively high thermostability and pH stability with its highest activity at 60 °C and pH 6.0. In addition, the activities of BGL were remarkably stimulated by the addition of 5 mM Na(+) or K(+). The enzyme showed strong ability to hydrolyze cellobiose with a K m and V max of 25.45 mM and 740.5 U/mg, respectively. The BGL was activated by glucose at concentration varying from 50 to 250 mM and tolerant to glucose inhibition with a K i of 800 mM glucose. The supplement of the purified BGL to the sugarcane bagasse hydrolysis mixture containing a commercial cellulase resulted in about 20 % enhancement of the released reducing sugars. These properties of the purified BGL should have important practical implication in its potential applications for better industrial production of glucose or bioethanol started from lignocellulosic biomass. PMID:25957152

  8. Physical optimization of production by deuteron irradiation of high specific activity (177g)Lu suitable for radioimmunotherapy.

    PubMed

    Manenti, Simone; Bonardi, Mauro L; Gini, Luigi; Groppi, Flavia

    2014-01-01

    Deuteron-induced nuclear reactions for generation of no-carrier-added (NCA) Lu isotopes were investigated using the stacked-foil activation technique on natural Yb targets at energies up to Ed=18.18MeV. The decay curve of ¹⁷⁷Yb, the growth curve of the cumulative (direct and indirect) and the direct production of (177g)Lu were determined. The analysis of these curves conducts to the evidence that the predominant route for the production of (177g)Lu is the indirect reaction ¹⁷⁶Yb(d,p)¹⁷⁷Yb, which decays to (177g)Lu. In the spectra acquired one year from the EOB the γ lines of (177m)Lu are not evident. A comparison between the calculated activity of (177g)Lu produced with a cyclotron and with a nuclear reactor is given. PMID:24666720

  9. Final Report for research grant "Development of Methods for High Specific Activity Labeling of Biomolecules Using Astatine-211 in Different Oxidation States"

    SciTech Connect

    Wilbur, D., Scott

    2011-12-14

    The overall objective of this research effort was to develop methods for labeling biomolecules with higher oxidation state species of At-211. This was to be done in an effort to develop reagents that had higher in vivo stability than the present carbon-bonded At-211-labeled compounds. We were unsuccessful in that effort, as none of the approaches studied provided reagents that were stable to in vivo deastatination. However, we gained a lot of information about At-211 in higher oxidation states. The studies proved to be very difficult as small changes in pH and other conditions appeared to change the nature of the species that obtained (by HPLC retention time analyses), with many of the species being unidentifiable. The fact that there are no stable isotopes of astatine, and the chemistry of the nearest halogen iodine is quite different, made it very difficult to interpret results of some experiments. With that said, we believe that a lot of valuable information was obtained from the studies. The research effort evaluated: (1) methods for chemical oxidation of At-211, (2) approaches to chelation of oxidized At-211, and (3) approaches to oxidation of astatophenyl compounds. A major hurdle that had to be surmounted to conduct the research was the development of HPLC conditions to separate and identify the various oxidized species formed. Attempts to develop conditions for separation of iodine and astatine species by normal and reversed-phase TLC and ITLC were not successful. However, we were successful in developing conditions (from a large number of attempts) to separate oxidized forms of iodine ([I-125]iodide, [I-125]iodate and [I-125]periodate) and astatine ([At-211]astatide, [At-211]astatate, [At-211]perastatate, and several unidentified At-211 species). Information on the basic oxidation and characterization of At-211 species is provided under Objective 1. Conditions were developed to obtain new At-211 labeling method where At-211 is chelated with the DOTA and NOTA chelation reagents. However, those species were unstable to isolation. Information is provided on those studies under Objective 2. We were successful in obtaining a highly oxidized form of arylastatine, but it did not appear to be stable in vivo. Information on those studies is provided under Objective 3. While we were not successful in obtaining reagents that contained oxidized forms of At-211 that were stable to in vivo deastatination, a lot of information was gained about the oxidation of At-211 and the stability of the species produced.

  10. High yield and high specific activity synthesis of [18F]Fallypride in a batch microfluidic reactor for micro-PET imaging

    PubMed Central

    Javed, Muhammad Rashed; Chen, Supin; Lei, Jack; Collins, Jeffrey; Sergeev, Maxim; Kim, Hee-Kwon; Kim, Chang-Jin; van Dam, R. Michael; Keng, Pei Yuin

    2015-01-01

    [18F]fallypride was synthesized in a batch microfluidic chip with a radiochemical yield of 65±6% (n=7) and an average specific activity of 730 GBq/μmol (20 Ci/μmol) (n=4). Specific activity was ~2-fold higher than [18F]fallypride synthesized on a macroscale radiosynthesizer, despite starting with significantly less radioactivity, and thus safer conditions, in the microchip. PMID:24326303

  11. Can gallium-68 compounds partly replace (18)F-FDG in PET molecular imaging?

    PubMed

    Pagou, Margarita; Zerizer, Imene; Al-Nahhas, Adil

    2009-01-01

    The development of gallium-68 -1,4,7,10-tetraazacyclodecane-1,4,7,10-tetraacetic acid ((68)Ga-DOTA) compounds was made possible due to the chemistry of (68)Ga, which matches the pharmacokinetics of many peptides, specially the chelators DOTA and DOTAderivatives with the formation of stable (68)Ga (3+) complexes. The availability of this tracer from a germanium-68-gallium-68 generator with a relatively long half-life makes it attractive to use in busy nuclear medicine departments, particularly those with limited access to cyclotrons. The recent clinical experience with (68)Ga-peptides includes imaging neuroendocrine tumours particularly carcinoid, as well as neuroectodermal tumours such as phaeochromocytoma and paraganglioma. In vitro and animal testing are still progressing alongside clinical studies, with promising results in the use of (68)Ga-DOTA-rhenium-cyclized alpha-melanocyte stimulating hormone (MSH) and (68)Ga-DOTA-napamide (NAP) in melanoma, (68)Ga-DOTA-PEG(4)-BN(7-14) (PESIN) for the imaging of bombesin receptor- positive tumours and (68)Ga-ethylene dicysteine-metronidazole (EC-MN) for imaging tumour hypoxia. In addition to tumours, (68)Ga- DOTA peptide inhibitor of vascular peptide protein 1(VAP-P1) is being assessed for imaging inflammatory reaction. An additional value following a positive scan is the use of beta emitters labelled to the same peptides for radionuclide treatment. In conclusion, the recent introduction of (68)Ga-peptides, made available by a convenient (68)Ga/(68)Ge generator, could greatly contribute to the management of a wide range of clinical conditions including tumours and inflammation. PMID:19675859

  12. The Role of Positron Emission Tomography With (68)Gallium (Ga)-Labeled Prostate-specific Membrane Antigen (PSMA) in the Management of Patients With Organ-confined and Locally Advanced Prostate Cancer Prior to Radical Treatment and After Radical Prostatectomy.

    PubMed

    Rai, Bhavan Prasad; Baum, Richard Paul; Patel, Amit; Hughes, Robert; Alonzi, Roberto; Lane, Tim; Adshead, Jim; Vasdev, Nikhil

    2016-09-01

    The role of positron emission tomography (PET) with (68)Gallium (Ga)-labeled prostate-specific membrane antigen (PSMA) imaging for prostate cancer is gaining prominence. Current imaging strategies, despite having progressed significantly, have limitations, in particular their ability to diagnose metastatic lymph node involvement. Preliminary results of PET with (68)Ga-labeled PSMA have shown encouraging results, particularly in the recurrent prostate cancer setting. Furthermore, the ability of PET with (68)Ga-labeled PSMA of playing a dual diagnostic and therapeutic setting (theranostics) is currently being investigated as well. PET with (68)Ga-labeled PSMA certainly has a role to play in bridging some of the voids in contemporary prostate cancer imaging tools. PMID:26790588

  13. (68)Ga-Bivalent Polypegylated Styrylpyridine Conjugates for Imaging Aβ Plaques in Cerebral Amyloid Angiopathy.

    PubMed

    Zha, Zhihao; Song, Jin; Choi, Seok Rye; Wu, Zehui; Ploessl, Karl; Smith, Megan; Kung, Hank

    2016-05-18

    Aβ plaques deposited on blood vessels are associated with cerebral amyloid angiopathy (CAA). In an effort to selectively map these Aβ plaques, we are reporting a new series of (68)Ga labeled styrylpyridine derivatives with high molecular weights. In vitro binding to Aβ plaques in post-mortem Alzheimer's disease (AD) brain tissue showed that these (68)Ga labeled bivalent styrylpyridines displayed good affinities and specificity (Ki < 30 nM). In vitro autoradiography using post-mortem AD brain sections showed specific binding of these (68)Ga complexes to Aβ plaques. Biodistribution studies in normal mice showed very low initial brain uptakes (<0.3% dose/g) indicating a low blood-brain barrier (BBB) penetration. The preliminary results suggest that (68)Ga labeled bivalent styrylpyridines may be promising candidates as PET imaging radiotracers for detecting CAA. PMID:27045547

  14. Phosphinic acid functionalized polyazacycloalkane chelators for radiodiagnostics and radiotherapeutics: unique characteristics and applications.

    PubMed

    Notni, Johannes; Šimeček, Jakub; Wester, Hans-Jürgen

    2014-06-01

    Given the wide application of positron emission tomography (PET), positron-emitting metal radionuclides have received much attention recently. Of these, gallium-68 has become particularly popular, as it is the only PET nuclide commercially available from radionuclide generators, therefore allowing local production of PET radiotracers independent of an on-site cyclotron. Hence, interest in optimized bifunctional chelators for the elaboration of (68) Ga-labeled bioconjugates has been rekindled as well, resulting in the development of improved triazacyclononane-triphosphinate (TRAP) ligand structures. The most remarkable features of these ligands are unparalleled selectivity for Ga(III) , rapid Ga(III) complexation kinetics, extraordinarily high thermodynamic stability, and kinetic inertness of the respective Ga(III) chelates. As a result, TRAP chelators exhibit very favorable (68) Ga-labeling properties. Based on the scaffolds NOPO (1,4,7-triazacyclononane-1,4-bis[methylene(hydroxymethyl)phosphinic acid]-7-[methylene(2-carboxyethyl)phosphinic acid]) and TRAP-Pr, tailored for convenient preparation of (68) Ga-labeled monomeric and multimeric bioconjugates, a variety of novel (68) Ga radiopharmaceuticals have been synthesized. These include bisphosphonates, somatostatin receptor ligands, prostate-specific membrane antigen (PSMA)-targeting peptides, and cyclic RGD pentapeptides, for in vivo PET imaging of bone, neuroendocrine tumors, prostate cancer, and integrin expression, respectively. Furthermore, TRAP-based (68) Ga-labeled gadolinium(III) complexes have been proposed as bimodal probes for PET/MRI, and a cyclen-based analogue of TRAP-Pr has been suggested for the elaboration of targeted radiotherapeutics comprising radiolanthanide ions. Thus, polyazacycloalkane-based polyphosphinic acid chelators are a powerful toolbox for pharmaceutical research, particularly for the development of (68) Ga radiopharmaceuticals. PMID:24700633

  15. Splenunculus Masquerading as Prostate-specific Membrane Antigen-positive Lymph Node Metastasis in a Patient With Prostate-specific Antigen Relapse After Radical Prostatectomy.

    PubMed

    Froehner, Michael; Zöphel, Klaus; Hölscher, Tobias; Laniado, Michael; Wirth, Manfred P

    2016-08-01

    A 45-year-old patient presented with prostate-specific antigen relapse after radical prostatectomy. Diagnostic workup revealed a (68)Ga-labeled prostate-specific membrane antigen-targeted ligand tracer uptaking nodule that was initially interpreted as lymph node metastasis but eventually identified as a splenunculus by scintigraphy with (99m)Tc pertechnetate-labeled heat-altered erythrocytes. Awareness of this constellation may spare unnecessary diagnostic procedures and inappropriate treatment. PMID:27125881

  16. Angiogenesis Imaging Using (68)Ga-RGD PET/CT: Therapeutic Implications.

    PubMed

    Eo, Jae Seon; Jeong, Jae Min

    2016-09-01

    Angiogenesis imaging is important for diagnostic and therapeutic treatment of various malignant and nonmalignant diseases. The Arg-Gly-Asp (RGD) sequence has been known to bind with the αvβ3 integrin that is expressed on the surface of angiogenic blood vessels or tumor cells. Thus, various radiolabeled derivatives of RGD peptides have been developed for angiogenesis imaging. Among the various radionuclides, (68)Ga was the most widely studied for RGD peptide imaging because of its excellent nuclear physical properties, easy-to-label chemical properties, and cost-effectiveness owing to the availability of a (68)Ge-(68)Ga generator. Thus, various (68)Ga-labeled RGD derivatives have been developed and applied for preclinical and clinical studies. Clinical trials were performed for both malignant and nonmalignant diseases. Breast cancer, glioma, and lung cancer were malignant, and myocardial infarction, atherosclerosis, and moyamoya disease were nonmalignant among the investigated diseases. Further, these (68)Ga-labeled RGD derivatives could be applied to assess the effects of antiangiogenic treatment or theragnosis or both, of cancers. In conclusion, the angiogenesis imaging technology using (68)Ga-labeled RGD derivatives might be useful for the development of new therapeutic assessments, and for diagnostic and theragnostic applications. PMID:27553467

  17. Pretargeted immuno-PET of CEA-expressing intraperitoneal human colonic tumor xenografts: a new sensitive detection method

    PubMed Central

    2012-01-01

    Background In this study, pretargeted immuno-positron-emission tomography [PET] with a bispecific monoclonal anti-carcinoembryonic antigen [CEA] (CEACAM5) × anti-hapten antibody (bispecific monoclonal antibody [bsmAb]) and a small (1.5 kD) peptide labeled with 68Ga was compared to fludeoxyglucose [18F-FDG]-PET for detecting intraperitoneal [i.p.] CEA-expressing human colonic tumor xenografts in nude mice. Methods Two groups of female BALB/c nude mice were inoculated with LS174T human colonic tumor cells i.p. One group received 5 MBq 18F-FDG, and the other received intravenous injections of the bsmAb, followed 16 h later with 5 MBq of 68Ga-labeled peptide. One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired. Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined. Results Within 1 h, high uptake of the 68Ga-labeled peptide in the tumor lesions (23.4 ± 7.2% ID/g) and low background activity levels were observed (e.g., tumor-to-intestine ratio, 58 ± 22). This resulted in a clear visualization of all intra-abdominal tumor lesions ≥ 10 μL and even some tumors as small as 5 μL (2 mm diameter). 18F-FDG efficiently localized in the tumors (8.7 ± 3.1% ID/g) but also showed physiological uptake in various normal tissues (e.g., tumor-to-intestine ratio, 3.9 ± 1.1). Conclusions Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions. PMID:22284761

  18. Proton beam simulation with MCNPX: Gallium metal activation estimates below 30 MeV relevant to the bulk production of 68Ge and 65Zn

    NASA Astrophysics Data System (ADS)

    Fassbender, M.; Arzumanov, A.; Jamriska, D. J.; Lyssukhin, S. N.; Trellue, H.; Waters, L. S.

    2007-08-01

    Several gallium metal targets containing Ga metal encapsulated in Nb shells were irradiated in a 30 MeV cyclotron beam. Proton and secondary neutron beam fluences as well as radionuclide activity formation were modeled using MCNP-X in combination with CINDER90. Targets were chemically processed using two anion exchange steps. Good agreement between measured radiochemical yields and MCNPX/CINDER estimates was observed. The separation principle introduced in this work was utilized for a small 68Ge/Ga generator column for 68Ga labeling purposes.

  19. A new 68Ge/68Ga generator system using an organic polymer containing N-methylglucamine groups as adsorbent for 68Ge.

    PubMed

    Nakayama, M; Haratake, M; Ono, M; Koiso, T; Harada, K; Nakayama, H; Yahara, S; Ohmomo, Y; Arano, Y

    2003-01-01

    A macroporous styrene-divinylbenzene copolymer containing N-methylglucamine groups was selected for a new 68Ge/68Ga generator system. This resin packed into a column effectively adsorbed the parent nuclide 68Ge. The daughter 68Ga was eluted from the resin with a solution of a low-affinity gallium chelating ligand such as citric or phosphoric acid. The 68Ge leakage was less than 0.0004% of the 68Ge adsorbed on the resin. By simple mixing of transferrin and desferoxamine conjugated HSA and IgG with the eluate from the column, 68Ga-labeling was completed in high yield. PMID:12485657

  20. Bifunctional Gallium-68 Chelators: Past, Present, and Future.

    PubMed

    Spang, Philipp; Herrmann, Christian; Roesch, Frank

    2016-09-01

    This article reviews the development of bifunctional chelates for synthesising (68)Ga radiopharmaceuticals. It structures the chelates into groups of macrocycles, nonmacrocycles, and chimeric derivatives. The most relevant bifunctional chelates are discussed in chelate structure, parameters of (68)Ga-labeling, and stability of the (68)Ga-chelate complexes. Furthermore those derivatives are included, where (67)Ga was applied instead of (68)Ga. A particular feature discussed is the ability of certain bifunctional chelate structures to function in kit-type preparation of the (68)Ga radiopharmaceuticals. Currently, nonmacrocyclic and chimeric derivates attract particular attention such as THP-derivates and DATA-derivates. PMID:27553464

  1. Peptide Receptor Radionuclide Therapy (PRRT) of Medullary and Nonmedullary Thyroid Cancer Using Radiolabeled Somatostatin Analogues.

    PubMed

    Salavati, Ali; Puranik, Ameya; Kulkarni, Harshad R; Budiawan, Hendra; Baum, Richard P

    2016-05-01

    As therapeutic options in advanced medullary and non-iodine avid differentiated (nonmedullary) thyroid cancers are limited and associated with significant toxicity, targeting of somatostatin receptors (SSTRs) for internal radiation therapy provides a promising option. Theranostics (therapy and diagnosis) using radiolabeled somatostatin analogues has proved to be a milestone in the management of SSTR-expressing tumors. Peptide receptor radionuclide therapy using (177)Lu-labeled or (90)Y-labeled somatostatin analogues may have a significant role in the management of medullary and nonmedullary thyroid cancers in those patients where PET/CT with (68)Ga-labeled somatostatin analogues demonstrates significant SSTR expression. PMID:27067502

  2. Scaling animal to human biodistribution of the radiopharmaceutical [68Ga]Ga-PSMA-HBED-CC

    NASA Astrophysics Data System (ADS)

    Parra, Pamela Ochoa; Veloza, Stella

    2016-07-01

    The radiotracer called 68Ga-labelled Glu-urea-Lys(Ahx)-HBED-CC ([68Ga]Ga-PSMA-HBED-CC) is a novel radiophar-maceutical for the detection of prostate cancer lesions by positron emission tomography (PET) imaging. Setting up a cost-effective manual synthesis of this radiotracer and making its clinical translation in Colombia will require two important elements: the evaluation of the procedure to yield a consistent product, meeting standards of radio-chemical purity and low toxicity and then, the evaluation of the radiation dosimetry. In this paper a protocol to extrapolate the biokinetic model made in normal mice to humans by using the computer software for internal dose assessment OLINDA/EXM® is presented as an accurate and standardized method for the calculation of radiation dosimetry estimates.

  3. Microwave-supported preparation of (68)Ga bioconjugates with high specific radioactivity.

    PubMed

    Velikyan, I; Beyer, G J; Långström, B

    2004-01-01

    The generator-produced positron-emitting (68)Ga (T(1/2) = 68 min) is of potential interest for clinical PET. (68)Ga as a metallic cation is suitable for complexation reactions with chelators, naked or conjugated, with peptides or other macromolecules. Large (68)Ga generator eluate volumes, metal traces from the generator column material, or reaction reagents, however, disturb a fast, reliable, and quantitative labeling procedure. In this paper we describe a simple technique, based on anion exchange, aiming first, to increase the (68)Ga concentration, second to purify it from competing impurities, and third to obtain a fast and quantitative (68)Ga-labeled peptide conjugate that can be applied in humans without further purification. Within 5 min one can obtain from the original 6 mL generator eluate a 200 microL (68)Ga preparation (volume reduction by a factor 30) that is suitable for direct and quantitative labeling of peptide conjugates. DOTATOC (DOTA-D-Phe(1)-Tyr(3)-octreotide, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was used as a test tracer for comparing the labeling properties of the different (68)Ga preparations. In combination with microwave heating, peptide conjugates of 0.5-1 nmol quantities could be labeled within 10 min with the full (68)Ga activity of a generator. Further purification of the (68)Ga-labeled peptide conjugate was no longer required since the nuclide incorporation was quantitative. The specific radioactivity (with respect to the peptide) was improved by a factor approximately 100 compared to the previously applied techniques using the original generator eluate. The commercial (68)Ge/(68)Ga generator from Obninsk in combination with this system for purification and concentration with an integrated microwave-supported labeling technology resulted in a kitlike technology for (68)Ga-tracer production. The first automated prototype using this technology is being tested. PMID:15149183

  4. Position for site-specific attachment of a DOTA chelator to synthetic affibody molecules has a different influence on the targeting properties of 68Ga- compared to 111in-labeled conjugates.

    PubMed

    Honarvar, Hadis; Strand, Joanna; Perols, Anna; Orlova, Anna; Selvaraju, Ram Kumar; Eriksson Karlström, Amelie; Tolmachev, Vladimir

    2014-01-01

    Affibody molecules, small (7 kDa) scaffold proteins, are a promising class of probes for radionuclide molecular imaging. Radiolabeling of Affibody molecules with the positron-emitting nuclide 68Ga would permit the use of positron emission tomography (PET), providing better resolution, sensitivity, and quantification accuracy than single-photon emission computed tomography (SPECT). The synthetic anti-HER2 ZHER2:S1 Affibody molecule was conjugated with DOTA at the N-terminus, in the middle of helix 3, or at the C-terminus. The biodistribution of 68Ga- and 111In-labeled Affibody molecules was directly compared in NMRI nu/nu mice bearing SKOV3 xenografts. The position of the chelator strongly influenced the biodistribution of the tracers, and the influence was more pronounced for 68Ga-labeled Affibody molecules than for the 111In-labeled counterparts. The best 68Ga-labeled variant was 68Ga-[DOTA-A1]-ZHER2:S1, which provided a tumor uptake of 13 ± 1 %ID/g and a tumor to blood ratio of 39 ± 12 at 2 hours after injection. 111In-[DOTA-A1]-ZHER2:S1 and 111In-[DOTA-K58]-ZHER2:S1 were equally good at this time point, providing a tumor uptake of 15 to 16 %ID/g and a tumor to blood ratio in the range of 60 to 80. In conclusion, the selection of the best position for a chelator in Affibody molecules can be used for optimization of their imaging properties. This may be important for the development of Affibody-based and other protein-based imaging probes. PMID:25249017

  5. Design of a Small-Molecule Drug Conjugate for Prostate Cancer Targeted Theranostics.

    PubMed

    Kumar, Amit; Mastren, Tara; Wang, Bin; Hsieh, Jer-Tsong; Hao, Guiyang; Sun, Xiankai

    2016-07-20

    Targeted therapy has become an effective strategy of precision medicine for cancer treatment. Based on the success of antibody-drug conjugates (ADCs), here we report a theranostic design of small-molecule drug conjugates (T-SMDCs) for targeted imaging and chemotherapy of prostate cancer. The structure of T-SMDCs built upon a polyethylene glycol (PEG) scaffold consists of (i) a chelating moiety for positron emission tomography (PET) imaging when labeled with (68)Ga, a positron-emitting radioisotope; (ii) a prostate specific membrane antigen (PSMA) specific ligand for prostate cancer targeting; and (iii) a cytotoxic drug (DM1) for chemotherapy. For proof-of-concept, such a T-SMDC, NO3A-DM1-Lys-Urea-Glu, was synthesized and evaluated. The chemical modification of Lys-Urea-Glu for the construction of the conjugate did not compromise its specific binding affinity to PSMA. The PSMA-mediated internalization of (68)Ga-labeled NO3A-DM1-Lys-Urea-Glu displayed a time-dependent manner, allowing the desired drug delivery and release within tumor cells. The antiproliferative activity of the T-SMDC showed a positive correlation with the PSMA expression level. Small animal PET imaging with (68)Ga-labeled NO3A-DM1-Lys-Urea-Glu exhibited significantly higher uptake (p < 0.01) in the PSMA positive PC3-PIP tumors (4.30 ± 0.20%ID/g) at 1 h postinjection than in the PSMA negative PC3-Flu tumors (1.12 ± 0.42%ID/g). Taken together, we have successfully designed and synthesized a T-SMDC system for prostate cancer targeted imaging and therapy. PMID:27248781

  6. Preclinical Evaluation of 68Ga-DOTA-Minigastrin for the Detection of Cholecystokinin-2/Gastrin Receptor–Positive Tumors

    PubMed Central

    Brom, Maarten; Joosten, Lieke; Laverman, Peter; Oyen, Wim J.G.; Béhé, Martin; Gotthardt, Martin; Boerman, Otto C.

    2011-01-01

    In comparison to somatostatin receptor scintigraphy, gastrin receptor scintigraphy using 111In-DTPA-minigastrin (MG0) showed added value in diagnosing neuroendocrine tumors. We investigated whether the 68Ga-labeled gastrin analogue DOTA-MG0 is suited for positron emission tomography (PET), which could improve image quality. Targeting of cholecystokinin-2 (CCK2)/gastrin receptor–positive tumor cells with DOTA-MG0 labeled with either 111In or 68Ga in vitro was investigated using the AR42J rat tumor cell line. Biodistribution was examined in BALB/c nude mice with a subcutaneous AR42J tumor. In vivo PET imaging was performed using a preclinical PET–computed tomographic scanner. DOTA-MG0 showed high receptor affinity in vitro. Biodistribution studies revealed high tumor uptake of 68Ga-DOTA-MG0: 4.4 ± 1.3 %ID/g at 1 hour postinjection. Coadministration of an excess unlabeled peptide blocked the tumor uptake (0.7 ± 0.1 %ID/g), indicating CCK2/gastrin receptor–mediated uptake (p = .0005). The biodistribution of 68Ga-DOTA-MG0 was similar to that of 111In-DOTA-MG0. Subcutaneous and intraperitoneal tumors were clearly visualized by small-animal PET imaging with 5 MBq 68Ga-DOTA-MG0. 111In- and 68Ga-labeled DOTA-MG0 specifically accumulate in CCK2/gastrin receptor–positive AR42J tumors with similar biodistribution apart from the kidneys. AR42J tumors were clearly visualized by microPET. Therefore, 68Ga-DOTA-MG0 is a promising tracer for PET imaging of CCK2/gastrin receptor–positive tumors in humans. PMID:21439259

  7. Increasing the Net Negative Charge by Replacement of DOTA Chelator with DOTAGA Improves the Biodistribution of Radiolabeled Second-Generation Synthetic Affibody Molecules.

    PubMed

    Westerlund, Kristina; Honarvar, Hadis; Norrström, Emily; Strand, Joanna; Mitran, Bogdan; Orlova, Anna; Eriksson Karlström, Amelie; Tolmachev, Vladimir

    2016-05-01

    A promising strategy to enable patient stratification for targeted therapies is to monitor the target expression in a tumor by radionuclide molecular imaging. Affibody molecules (7 kDa) are nonimmunoglobulin scaffold proteins with a 25-fold smaller size than intact antibodies. They have shown an apparent potential as molecular imaging probes both in preclinical and clinical studies. Earlier, we found that hepatic uptake can be reduced by the incorporation of negatively charged purification tags at the N-terminus of Affibody molecules. We hypothesized that liver uptake might similarly be reduced by positioning the chelator at the N-terminus, where the chelator-radionuclide complex will provide negative charges. To test this hypothesis, a second generation synthetic anti-HER2 ZHER2:2891 Affibody molecule was synthesized and labeled with (111)In and (68)Ga using DOTAGA and DOTA chelators. The chelators were manually coupled to the N-terminus of ZHER2:2891 forming an amide bond. Labeling DOTAGA-ZHER2:2891 and DOTA-ZHER2:2891 with (68)Ga and (111)In resulted in stable radioconjugates. The tumor-targeting and biodistribution properties of the (111)In- and (68)Ga-labeled conjugates were compared in SKOV-3 tumor-bearing nude mice at 2 h postinjection. The HER2-specific binding of the radioconjugates was verified both in vitro and in vivo. Using the DOTAGA chelator gave significantly lower radioactivity in liver and blood for both radionuclides. The (111)In-labeled conjugates showed more rapid blood clearance than the (68)Ga-labeled conjugates. The most pronounced influence of the chelators was found when they were labeled with (68)Ga. The DOTAGA chelator gave significantly higher tumor-to-blood (61 ± 6 vs 23 ± 5, p < 0.05) and tumor-to-liver (10.4 ± 0.6 vs 4.5 ± 0.5, p < 0.05) ratios than the DOTA chelator. This study demonstrated that chelators may be used to alter the uptake of Affibody molecules, and most likely other scaffold-based imaging probes, for improvement

  8. Evaluation of (68)Ga- and (177)Lu-DOTA-PEG4-LLP2A for VLA-4-Targeted PET Imaging and Treatment of Metastatic Melanoma.

    PubMed

    Beaino, Wissam; Nedrow, Jessie R; Anderson, Carolyn J

    2015-06-01

    Malignant melanoma is a highly aggressive cancer, and the incidence of this disease is increasing worldwide at an alarming rate. Despite advances in the treatment of melanoma, patients with metastatic disease still have a poor prognosis and low survival rate. New strategies, including targeted radiotherapy, would provide options for patients who become resistant to therapies such as BRAF inhibitors. Very late antigen-4 (VLA-4) is expressed on melanoma tumor cells in higher levels in more aggressive and metastatic disease and may provide an ideal target for drug delivery and targeted radiotherapy. In this study, we evaluated (177)Lu- and (68)Ga-labeled DOTA-PEG4-LLP2A as a VLA-4-targeted radiotherapeutic with a companion PET agent for diagnosis and monitoring metastatic melanoma treatment. DOTA-PEG4-LLP2A was synthesized by solid-phase synthesis. The affinity of (177)Lu- and (68)Ga-labeled DOTA-PEG4-LLP2A to VLA-4 was determined in B16F10 melanoma cells by saturation binding and competitive binding assays, respectively. Biodistribution of the LLP2A conjugates was determined in C57BL/6 mice bearing B16F10 subcutaneous tumors, while PET/CT imaging was performed in subcutaneous and metastatic models. (177)Lu-DOTA-PEG4-LLP2A showed high affinity to VLA-4 with a Kd of 4.1 ± 1.5 nM and demonstrated significant accumulation in the B16F10 melanoma tumor after 4 h (31.5 ± 7.8%ID/g). The tumor/blood ratio of (177)Lu-DOTA-PEG4-LLP2A was highest at 24 h (185 ± 26). PET imaging of metastatic melanoma with (68)Ga-DOTA-PEG4-LLP2A showed high uptake in sites of metastases and correlated with bioluminescence imaging of the tumors. These data demonstrate that (177)Lu-DOTA-PEG4-LLP2A has potential as a targeted therapeutic for treating melanoma as well as other VLA-4-expressing tumors. In addition, (68)Ga-DOTA-PEG4-LLP2A is a readily translatable companion PET tracer for imaging of metastatic melanoma. PMID:25919487

  9. Design of Internalizing PSMA-specific Glu-ureido-based Radiotherapeuticals

    PubMed Central

    Wüstemann, Till; Bauder-Wüst, Ulrike; Schäfer, Martin; Eder, Matthias; Benesova, Martina; Leotta, Karin; Kratochwil, Clemens; Haberkorn, Uwe; Kopka, Klaus; Mier, Walter

    2016-01-01

    Despite the progress in diagnosis and treatment, prostate cancer (PCa) is one of the main causes for cancer-associated deaths among men. Recently, prostate-specific membrane antigen (PSMA) binding tracers have revolutionized the molecular imaging of this disease. The translation of these tracers into therapeutic applications is challenging because of high PSMA-associated kidney uptake. While both the tumor uptake and the uptake in the kidneys are PSMA-specific, the kidneys show a more rapid clearance than tumor lesions. Consequently, the potential of endoradiotherapeutic drugs targeting PSMA is highly dependent on a sustained retention in the tumor - ideally achieved by predominant internalization of the respective tracer. Previously, we were able to show that the pharmacokinetics of the tracers containing the Glu-urea-based binding motif can be further enhanced with a specifically designed linker. Here, we evaluate an eventual influence of the chelator moiety on the pharmacokinetics, including the tumor internalization. A series of tracers modified by different chelators were synthesized using solid phase chemistry. The conjugates were radiolabeled to evaluate the influence on the receptor binding affinity, the ligand-induced internalization and the biodistribution behavior. Competitive binding and internalization assays were performed on PSMA positive LNCaP cells and the biodistribution of the most promising compound was evaluated by positron emission tomography (PET) in LNCaP-tumor-bearing mice. Interestingly, conjugation of the different chelators did not cause significant differences: all compounds showed nanomolar binding affinities with only minor differences. PET imaging of the 68Ga-labeled CHX-A''-DTPA conjugate revealed that the chelator moiety does not impair the specificity of tumor uptake when compared to the gold standard PSMA-617. However, strong differences of the internalization ratios caused by the chelator moiety were observed: differences in

  10. Design of Internalizing PSMA-specific Glu-ureido-based Radiotherapeuticals.

    PubMed

    Wüstemann, Till; Bauder-Wüst, Ulrike; Schäfer, Martin; Eder, Matthias; Benesova, Martina; Leotta, Karin; Kratochwil, Clemens; Haberkorn, Uwe; Kopka, Klaus; Mier, Walter

    2016-01-01

    Despite the progress in diagnosis and treatment, prostate cancer (PCa) is one of the main causes for cancer-associated deaths among men. Recently, prostate-specific membrane antigen (PSMA) binding tracers have revolutionized the molecular imaging of this disease. The translation of these tracers into therapeutic applications is challenging because of high PSMA-associated kidney uptake. While both the tumor uptake and the uptake in the kidneys are PSMA-specific, the kidneys show a more rapid clearance than tumor lesions. Consequently, the potential of endoradiotherapeutic drugs targeting PSMA is highly dependent on a sustained retention in the tumor - ideally achieved by predominant internalization of the respective tracer. Previously, we were able to show that the pharmacokinetics of the tracers containing the Glu-urea-based binding motif can be further enhanced with a specifically designed linker. Here, we evaluate an eventual influence of the chelator moiety on the pharmacokinetics, including the tumor internalization. A series of tracers modified by different chelators were synthesized using solid phase chemistry. The conjugates were radiolabeled to evaluate the influence on the receptor binding affinity, the ligand-induced internalization and the biodistribution behavior. Competitive binding and internalization assays were performed on PSMA positive LNCaP cells and the biodistribution of the most promising compound was evaluated by positron emission tomography (PET) in LNCaP-tumor-bearing mice. Interestingly, conjugation of the different chelators did not cause significant differences: all compounds showed nanomolar binding affinities with only minor differences. PET imaging of the (68)Ga-labeled CHX-A''-DTPA conjugate revealed that the chelator moiety does not impair the specificity of tumor uptake when compared to the gold standard PSMA-617. However, strong differences of the internalization ratios caused by the chelator moiety were observed: differences in

  11. Malignant presacral ghrelinoma with long-standing hyperghrelinaemia

    PubMed Central

    Gustafsson, Thomas; Wenzel, Ralf; Wierup, Nils; Sundler, Frank; Kulkarni, Harshad; Baum, Richard P.

    2015-01-01

    Background. A 57-year old man with low-back pain was found to have a 3 × 3 × 3 cm presacral neuroendocrine tumour (NET) with widespread metastases, mainly to the skeleton. His neoplastic disease responded well to peptide receptor radionuclide therapy (PRRT) with the radiotagged somatostatin agonist 177Lu-DOTATATE. During almost 10 years he was fit for a normal life. He succumbed to an intraspinal dissemination. Procedures. A resection of the rectum, with a non-radical excision of the adjacent NET, was made. In addition to computerized tomography (CT), receptor positron emission tomography (PET) with 68Ga-labelled somatostatin analogues was used. Observations. The NET showed the growth pattern and immunoprofile of a G2 carcinoid. A majority cell population displayed immunoreactivity to ghrelin, exceptionally with co-immunoreactivity to motilin. Somatostatin receptor scintigraphy and 68Ga-DOTATATE PET-CT demonstrated uptake in the metastatic lesions. High serum concentrations of total (desacyl-)ghrelin were found with fluctuations reflecting the severity of the symptoms. In contrast, the concentrations of active (acyl-)ghrelin were consistently low, as were those of chromogranin A (CgA). Conclusions. Neoplastically transformed ghrelin cells can release large amounts of desacyl-ghrelin, evoking an array of non-specific clinical symptoms. Despite an early dissemination to the skeleton, a ghrelinoma can be compatible with longevity after adequate radiotherapy. PMID:26095011

  12. Targeted molecular imaging in oncology.

    PubMed

    Yang, David J; Kim, E Edmund; Inoue, Tomio

    2006-01-01

    Improvement of scintigraphic tumor imaging is extensively determined by the development of more tumor specific radiopharmaceuticals. Thus, to improve the differential diagnosis, prognosis, planning and monitoring of cancer treatment, several functional pharmaceuticals have been developed. Application of molecular targets for cancer imaging, therapy and prevention using generator-produced isotopes is the major focus of ongoing research projects. Radionuclide imaging modalities (positron emission tomography, PET; single photon emission computed tomography, SPECT) are diagnostic cross-sectional imaging techniques that map the location and concentration of radionuclide-labeled radiotracers. 99mTc- and 68Ga-labeled agents using ethylenedicysteine (EC) as a chelator were synthesized and their potential uses to assess tumor targets were evaluated. 99mTc (t1/2 = 6 hr, 140 keV) is used for SPECT and 68Ga (t1/2 = 68 min, 511 keV) for PET. Molecular targets labeled with Tc-99m and Ga-68 can be utilized for prediction of therapeutic response, monitoring tumor response to treatment and differential diagnosis. Molecular targets for oncological research in (1) cell apoptosis, (2) gene and nucleic acid-based approach, (3) angiogenesis (4) tumor hypoxia, and (5) metabolic imaging are discussed. Numerous imaging ligands in these categories have been developed and evaluated in animals and humans. Molecular targets were imaged and their potential to redirect optimal cancer diagnosis and therapeutics were demonstrated. PMID:16485568

  13. The Synthesis and Evaluations of the 68Ga-Lissamine Rhodamine B (LRB) as a New Radiotracer for Imaging Tumors by Positron Emission Tomography

    PubMed Central

    Li, Xuena; Yin, Yafu; Du, Bulin; Li, Na; Li, Yaming

    2016-01-01

    Purpose. The aim of this study is to synthesize and evaluate 68Ga-labeled Lissamine Rhodamine B (LRB) as a new radiotracer for imaging MDA-MB-231 and MCF-7 cells induced tumor mice by positron emission tomography (PET). Methods. Firstly, we performed the radio synthesis and microPET imaging of 68Ga(DOTA-LRB) in athymic nude mice bearing MDA-MB-231 and MCF-7 human breast cancer xenografts. Additionally, the evaluations of 18F-fluorodeoxyglucose (FDG), as a glucose metabolism radiotracer for imaging tumors in the same xenografts, have been conducted as a comparison. Results. The radiochemical purity of 68Ga(DOTA-LRB) was >95%. MicroPET dynamic imaging revealed that the uptake of 68Ga(DOTA-LRB) was mainly in normal organs, such as kidney, heart, liver, and brain and mainly excreted from kidney. The MDA-MB-231 and MCF-7 tumors were not clearly visible in PET images at 5, 15, 30, 40, 50, and 60 min after injection of 68Ga(DOTA-LRB). The tumor uptake values of 18F-FDG were 3.79 ± 0.57 and 1.93 ± 0.48%ID/g in MDA-MB-231 and MCF-7 tumor xenografts, respectively. Conclusions. 68Ga(DOTA-LRB) can be easily synthesized with high radiochemical purity and stability; however, it may be not an ideal PET radiotracer for imaging of MDR-positive tumors. PMID:26949707

  14. Design, construction and testing of a low-cost automated (68)Gallium-labeling synthesis unit for clinical use.

    PubMed

    Heidari, Pedram; Szretter, Alicia; Rushford, Laura E; Stevens, Maria; Collier, Lee; Sore, Judit; Hooker, Jacob; Mahmood, Umar

    2016-01-01

    The interest in (68)Gallium labeled PET probes continues to increase around the world. Widespread use in Europe and Asia has led to great interest for use at numerous sites in the US. One barrier to entry is the cost of the automated synthesis units for relatively simple labeling procedures. We describe the construction and testing of a relatively low-cost automated (68)Ga-labeling unit for human-use. We provide a guide for construction, including part lists and synthesis timelists to facilitate local implementation. Such inexpensive systems could help increase use around the globe and in the US in particular by removing one of the barriers to greater widespread availability. The developed automated synthesis unit reproducibly synthesized (68)Ga-DOTATOC with average yield of 71 ± 8% and a radiochemical purity ≥ 95% in a synthesis time of 25 ± 1 minutes. Automated product yields are comparable to that of manual synthesis. We demonstrate in-house construction and use of a low-cost automated synthesis unit for labeling of DOTATOC and similar peptides with (68)Gallium. PMID:27508104

  15. Current use of PSMA-PET in prostate cancer management.

    PubMed

    Maurer, Tobias; Eiber, Matthias; Schwaiger, Markus; Gschwend, Jürgen E

    2016-04-01

    Currently, the findings of imaging procedures used for detection or staging of prostate cancer depend on morphology of lymph nodes or bone metabolism and do not always meet diagnostic needs. Prostate-specific membrane antigen (PSMA), a transmembrane protein that has considerable overexpression on most prostate cancer cells, has gained increasing interest as a target molecule for imaging. To date, several small compounds for labelling PSMA have been developed and are currently being investigated as imaging probes for PET with the (68)Ga-labelled PSMA inhibitor Glu-NH-CO-NH-Lys(Ahx)-HBED-CC being the most widely studied agent. (68)Ga-PSMA-PET imaging in combination with multiparametric MRI (mpMRI) might provide additional molecular information on cancer localization within the prostate. In patients with primary prostate cancer of intermediate-risk to high-risk, PSMA-based imaging has been reported to improve detection of metastatic disease compared with CT or mpMRI, rendering additional cross-sectional imaging or bone scintigraphy unnecessary. Furthermore, in patients with biochemically recurrent prostate cancer, use of (68)Ga-PSMA-PET imaging has been shown to increase detection of metastatic sites, even at low serum PSA values, compared with conventional imaging or PET examination with different tracers. Thus, although current knowledge is still limited and derived mostly from retrospective series, PSMA-based imaging holds great promise to improve prostate cancer management. PMID:26902337

  16. Design, construction and testing of a low-cost automated 68Gallium-labeling synthesis unit for clinical use

    PubMed Central

    Heidari, Pedram; Szretter, Alicia; Rushford, Laura E; Stevens, Maria; Collier, Lee; Sore, Judit; Hooker, Jacob; Mahmood, Umar

    2016-01-01

    The interest in 68Gallium labeled PET probes continues to increase around the world. Widespread use in Europe and Asia has led to great interest for use at numerous sites in the US. One barrier to entry is the cost of the automated synthesis units for relatively simple labeling procedures. We describe the construction and testing of a relatively low-cost automated 68Ga-labeling unit for human-use. We provide a guide for construction, including part lists and synthesis timelists to facilitate local implementation. Such inexpensive systems could help increase use around the globe and in the US in particular by removing one of the barriers to greater widespread availability. The developed automated synthesis unit reproducibly synthesized 68Ga-DOTATOC with average yield of 71 ± 8% and a radiochemical purity ≥ 95% in a synthesis time of 25 ± 1 minutes. Automated product yields are comparable to that of manual synthesis. We demonstrate in-house construction and use of a low-cost automated synthesis unit for labeling of DOTATOC and similar peptides with 68Gallium. PMID:27508104

  17. Imaging hypoxia in gliomas

    PubMed Central

    Mendichovszky, I; Jackson, A

    2011-01-01

    Hypoxia plays a central role in tumour development, angiogenesis, growth and resistance to treatment. Owing to constant developments in medical imaging technology, significant advances have been made towards in vitro and in vivo imaging of hypoxia in a variety of tumours, including gliomas of the central nervous system. The aim of this article is to review the literature on imaging approaches currently available for measuring hypoxia in human gliomas and provide an insight into recent advances and future directions in this field. After a brief overview of hypoxia and its importance in gliomas, several methods of measuring hypoxia will be presented. These range from invasive monitoring by Eppendorf polarographic O2 microelectrodes, positron electron tomography (PET) tracers based on 2-nitroimidazole compounds [18F-labelled fluoro-misonidazole (18F-MISO) or 1-(2-[(18)F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP-170)], 64Cu-ATSM Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) or 99mTc- and 68Ga-labelled metronidazole (MN) agents to advanced MRI methods, such as blood oxygenation level dependent (BOLD) MRI, oxygen-enhanced MRI, diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI) and 1H-magnetic resonance spectroscopy. PMID:22433825

  18. Advances in the Diagnosis of Neuroendocrine Neoplasms.

    PubMed

    Kulkarni, Harshad R; Singh, Aviral; Baum, Richard P

    2016-09-01

    Somatostatin receptor PET/CT using (68)Ga-labeled somatostatin analogs, is a mainstay for the evaluation of the somatostatin receptor status in neuroendocrine neoplasms. In addition, the assessment of glucose metabolism by (18)F-FDG PET/CT at diagnosis can overcome probable shortcomings of histopathologic grading. This offers a systematic theranostic approach for the management of neuroendocrine neoplasms, that is, patient selection for the appropriate treatment-surgery, somatostatin analogs, peptide receptor radionuclide therapy, targeted therapies like everolimus and sunitinib, or chemotherapy-and also for therapy response monitoring. Novel targets, for example, the chemokine receptor CXCR4 in higher-grade tumors and glucagon like peptide-1 receptor in insulinomas, appear promising for imaging. Scandium-44 and Copper-64, especially on account of their longer half-life (for pretherapeutic dosimetry) and cyclotron production (which favors mass production), might be the potential alternatives to (68)Ga for PET/CT imaging. The future of molecular imaging lies in Radiomics, that is, qualitative and quantitative characterization of tumor phenotypes in correlation with tumor genomics and proteomics, for a personalized cancer management. PMID:27553465

  19. Investigations on the Ga(III) Complex of EOB-DTPA and Its 68Ga Radiolabeled Analogue.

    PubMed

    Greiser, Julia; Niksch, Tobias; Weigand, Wolfgang; Freesmeyer, Martin

    2016-01-01

    We demonstrate a method for the isolation of EOB-DTPA (3,6,9-triaza-3,6,9-tris(carboxymethyl)-4-(ethoxybenzyl)-undecanedioic acid) from its Gd(III) complex and protocols for the preparation of its novel non-radioactive, i.e., natural Ga(III) as well as radioactive (68)Ga complex. The ligand as well as the Ga(III) complex were characterized by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry and elemental analysis. (68)Ga was obtained by a standard elution method from a (68)Ge/(68)Ga generator. Experiments to evaluate the (68)Ga-labeling efficiency of EOB-DTPA at pH 3.8-4.0 were performed. Established analysis techniques radio TLC (thin layer chromatography) and radio HPLC (high performance liquid chromatography) were used to determine the radiochemical purity of the tracer. As a first investigation of the (68)Ga tracers' lipophilicity the n-octanol/water distribution coefficient of (68)Ga species present in a pH 7.4 solution was determined by an extraction method. In vitro stability measurements of the tracer in various media at physiological pH were performed, revealing different rates of decomposition. PMID:27584545

  20. 68Ga-complex lipophilicity and the targeting property of a urea-based PSMA inhibitor for PET imaging.

    PubMed

    Eder, Matthias; Schäfer, Martin; Bauder-Wüst, Ulrike; Hull, William-Edmund; Wängler, Carmen; Mier, Walter; Haberkorn, Uwe; Eisenhut, Michael

    2012-04-18

    Urea-based inhibitors of the prostate-specific membrane antigen (PSMA) represent low-molecular-weight pepidomimetics showing the ability to image PSMA-expressing prostate tumors. The highly efficient, acyclic Ga(III) chelator N,N'-bis [2-hydroxy-5-(carboxyethyl)benzyl] ethylenediamine-N,N'- diacetic acid (HBED-CC) was introduced as a lipophilic side chain into the hydrophilic pharmacophore Glu-NH-CO-NH-Lys which was found favorable to interact with the PSMA "active binding site". This report describes the syntheses, in vitro binding analyses, and biodistribution data of the radiogallium labeled PSMA inhibitor Glu-NH-CO-NH-Lys(Ahx)-HBED-CC in comparison to the corresponding DOTA conjugate. The binding properties were analyzed using competitive cell binding and enzyme-based assays followed by internalization experiments. Compared to the DOTA-conjugate, the HBED-CC derivative showed reduced unspecific binding and considerable higher specific internalization in LNCaP cells. The (68)Ga complex of the HBED-CC ligand exhibited higher specificity for PSMA expressing tumor cells resulting in improved in vivo properties. (68)Ga labeled Glu-NH-CO-NH-Lys(Ahx)-HBED-CC showed fast blood and organ clearances, low liver accumulation, and high specific uptake in PSMA expressing organs and tumor. It could be demonstrated that the PET-imaging property of a urea-based PSMA inhibitor could significantly be improved with HBED-CC. PMID:22369515

  1. Improving the stability of peptidic radiotracers by the introduction of artificial scaffolds: which structure element is most useful?

    PubMed

    Bacher, Lisa; Fischer, Gabriel; Litau, Shanna; Schirrmacher, Ralf; Wängler, Björn; Baller, Marko; Wängler, Carmen

    2015-08-01

    Peptidic radiotracers are highly potent substances for the specific in vivo imaging of various biological targets with Single Photon Emission Computed Tomography and Positron Emission Tomography. However, some radiolabeled peptides such as bombesin analogs were shown to exhibit only a limited stability, hampering a successful target visualization. One option to positively influence the stability of radiolabeled peptides is the introduction of certain artificial molecular scaffolds. In order to comparatively assess the influence of different structure elements on the stability of radiolabeled peptides and to identify those structure elements being most useful for peptide radiotracer stabilization, several monomeric and dimeric bombesin derivatives were synthesized, exhibiting differing molecular designs and the chelator NODAGA for (68) Ga-labeling. The radiolabeled peptides were evaluated regarding their in vitro stability in human serum to determine the influence of the introduced molecular scaffolds on the peptides' serum stabilities. The results of the evaluations showed that the introduction of scaffold structures and the overall molecular design have a substantial impact on the stabilities of the resulting peptidic radiotracers. But besides some general trends found using certain scaffold structures, the obtained results point to the necessity to empirically assess their influence on stability for each susceptible peptidic radiotracer individually. PMID:26219022

  2. Positron emission tomographic imaging of copper 64- and gallium 68-labeled chelator conjugates of the somatostatin agonist tyr3-octreotate.

    PubMed

    Nedrow, Jessie R; White, Alexander G; Modi, Jalpa; Nguyen, Kim; Chang, Albert J; Anderson, Carolyn J

    2014-01-01

    The bifunctional chelator and radiometal have been shown to have a direct effect on the pharmacokinetics of somatostatin receptor (SSTR)-targeted imaging agents. We evaluated three Y3-TATE analogues conjugated to NOTA-based chelators for radiolabeling with 64Cu and 68Ga for small-animal positron emission tomographic/computed tomographic (PET/CT) imaging. Two commercially available NOTA analogues, p-SCN-Bn-NOTA and NODAGA, were evaluated. The p-SCN-Bn-NOTA analogues were conjugated to Y3-TATE through β-Ala and PEG8 linkages. The NODAGA chelator was directly conjugated to Y3-TATE. The analogues labeled with 64Cu or 68Ga were analyzed in vitro for binding affinity and internalization and in vivo by PET/CT imaging, biodistribution, and Cerenkov imaging (68Ga analogues). We evaluated the effects of the radiometals, chelators, and linkers on the performance of the SSTR subtype 2--targeted imaging agents and also compared them to a previously reported agent, 64Cu-CB-TE2A-Y3-TATE. We found that the method of conjugation, particularly the length of the linkage between the chelator and the peptide, significantly impacted tumor and nontarget tissue uptake and clearance. Among the 64Cu- and 68Ga-labeled NOTA analogues, NODAGA-Y3-TATE had the most optimal in vivo behavior and was comparable to 64Cu-CB-TE2A-Y3-TATE. An advantage of NODAGA-Y3-TATE is that it allows labeling with 64Cu and 68Ga, providing a versatile PET probe for imaging SSTr subtype 2-positive tumors. PMID:25060207

  3. Affibody-mediated PET imaging of HER3 expression in malignant tumours

    PubMed Central

    Rosestedt, Maria; Andersson, Ken G.; Mitran, Bogdan; Tolmachev, Vladimir; Löfblom, John; Orlova, Anna; Ståhl, Stefan

    2015-01-01

    Human epidermal growth factor receptor 3 (HER3) is involved in the progression of various cancers and in resistance to therapies targeting the HER family. In vivo imaging of HER3 expression would enable patient stratification for anti-HER3 immunotherapy. Key challenges with HER3-targeting are the relatively low expression in HER3-positive tumours and HER3 expression in normal tissues. The use of positron-emission tomography (PET) provides advantages of high resolution, sensitivity and quantification accuracy compared to SPECT. Affibody molecules, imaging probes based on a non-immunoglobulin scaffold, provide high imaging contrast shortly after injection. The aim of this study was to evaluate feasibility of PET imaging of HER3 expression using 68Ga-labeled affibody molecules. The anti-HER3 affibody molecule HEHEHE-Z08698-NOTA was successfully labelled with 68Ga with high yield, purity and stability. The agent bound specifically to HER3-expressing cancer cells in vitro and in vivo. At 3 h pi, uptake of 68Ga-HEHEHE-Z08698-NOTA was significantly higher in xenografts with high HER3 expression (BT474, BxPC-3) than in xenografts with low HER3 expression (A431). In xenografts with high expression, tumour-to-blood ratios were >20, tumour-to-muscle >15, and tumour-to-bone >7. HER3-positive xenografts were visualised using microPET 3 h pi. In conclusion, PET imaging of HER3 expression is feasible using 68Ga-HEHEHE-Z08698-NOTA shortly after administration. PMID:26477646

  4. AMD3100: A Versatile Platform for CXCR4 Targeting (68)Ga-Based Radiopharmaceuticals.

    PubMed

    Poty, Sophie; Gourni, Eleni; Désogère, Pauline; Boschetti, Frédéric; Goze, Christine; Maecke, Helmut R; Denat, Franck

    2016-03-16

    CXCR4 is a G protein-coupled receptor (GPCR), which is overexpressed in numerous diseases, particularly in multiple cancers. Therefore, this receptor represents a valuable target for imaging and therapeutic purposes. Among the different approaches, which were developed for CXCR4 imaging, a CXCR4 antagonist biscyclam system (AMD3100, also called Mozobil), currently used in the clinic for the mobilization of hematopoietic stem cells, was radiolabeled with different radiometals such as (62)Zn, (64)Cu, (67)Ga, or (99m)Tc. However, cyclam is not an ideal chelator for most of these radiometals, and could lead to the release of the radionuclide in vivo. In the current study, a new family of CXCR4 imaging agents is presented, in which AMD3100 is used as a carrier for specific delivery of an imaging reporter, i.e., a (68)Ga complex for PET imaging. AMD3100 was functionalized on the phenyl moiety with different linkers, either ethylenediamine or diamino-polyethylene glycol 3 (PEG3). The resulting AMD3100 analogues were further coupled with two different chelators, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) or 1,4,7-triazacyclononane-1-glutaric acid-4,7-acetic acid (NODAGA). Five potential CXCR4 targeting agents were obtained. The derived AMD3100-based ligands were labeled with (68)Ga, highlighting the influence of the spacer nature on the (68)Ga-labeling yield. The lipophilic character of the different systems was also investigated, as well as their affinity for the CXCR4 receptor. The most promising compound was further evaluated in vivo in H69 tumor xenografts by biodistribution and PET imaging studies, validating the proof of principle of our concept. PMID:26886512

  5. A practical guide to the construction of radiometallated bioconjugates for positron emission tomography

    PubMed Central

    Zeglis, Brian M.

    2013-01-01

    Positron emission tomography (PET) has become a vital imaging modality in the diagnosis and treatment of disease, most notably cancer. A wide array of small molecule PET radiotracers have been developed that employ the short half-life radionuclides 11C, 13N, 15O, and 18F. However, PET radiopharmaceuticals based on biomolecular targeting vectors have been the subject of dramatically increased research in both the laboratory and the clinic. Typically based on antibodies, oligopeptides, or oligonucleotides, these tracers have longer biological half-lives than their small molecule counterparts and thus require labeling with radionuclides with longer, complementary radioactive half-lives, such as the metallic isotopes 64Cu, 68Ga, 86Y, and 89Zr. Each bioconjugate radiopharmaceutical has four component parts: biomolecular vector, radiometal, chelator, and covalent link between chelator and biomolecule. With the exception of the radiometal, a tremendous variety of choices exists for each of these pieces, and a plethora of different chelation, conjugation, and radiometallation strategies have been utilized to create agents ranging from 68Ga-labeled pentapeptides to 89Zr-labeled monoclonal antibodies. Herein, the authors present a practical guide to the construction of radiometal-based PET bioconjugates, in which the design choices and synthetic details of a wide range of biomolecular tracers from the literature are collected in a single reference. In assembling this information, the authors hope both to illuminate the diverse methods employed in the synthesis of these agents and also to create a useful reference for molecular imaging researchers both experienced and new to the field. PMID:21442098

  6. Fusarinine C, a novel siderophore-based bifunctional chelator for radiolabeling with Gallium-68

    PubMed Central

    Zhai, Chuangyan; Summer, Dominik; Rangger, Christine; Haas, Hubertus; Haubner, Roland; Decristoforo, Clemens

    2015-01-01

    Fusarinine C (FSC), a siderophore-based chelator coupled with the model peptide c(RGDfK) (FSC(succ-RGD)3), revealed excellent targeting properties in vivo using positron emission tomography (PET). Here, we report the details of radiolabeling conditions and specific activity as well as selectivity for 68Ga. 68Ga labeling of FSC(succ-RGD)3 was optimized regarding peptide concentration, pH, temperature, reaction time, and buffer system. Specific activity (SA) of [68Ga]FSC(succ-RGD)3 was compared with 68Ga-1,4,7-triazacyclononane, 1-glutaric acid-4,7 acetic acid RGD ([68Ga]NODAGA-RGD). Stability was evaluated in 1000-fold ethylenediaminetetraacetic acid (EDTA) solution (pH 7) and phosphate-buffered saline (PBS). Metal competition tests (Fe, Cu, Zn, Al, and Ni) were carried out using [68Ga]-triacetylfusarinine C. High radiochemical yield was achieved within 5 min at room temperature, in particular allowing labeling with 68Ga up to pH 8 with excellent stability in 1000-fold EDTA solution and PBS. The 10-fold to 20-fold lower concentrations of FSC(succ-RGD)3 led to the same radiochemical yield compared with [68Ga]NODAGA-RGD with SA up to 1.8 TBq/μmol. Metal competition tests showed high selective binding of 68Ga to FSC. FSC is a multivalent siderophore-based bifunctional chelator allowing fast and highly selective labeling with 68Ga in a wide pH range and results in stable complexes with high SA. Thus it is exceptionally well suited for the development of new 68Ga-tracers for in vivo molecular imaging with PET. PMID:25874571

  7. Radiolabeling of DOTA-like conjugated peptides with generator-produced (68)Ga and using NaCl-based cationic elution method.

    PubMed

    Mueller, Dirk; Breeman, Wouter A P; Klette, Ingo; Gottschaldt, Michael; Odparlik, Andreas; Baehre, Manfred; Tworowska, Izabela; Schultz, Michael K

    2016-06-01

    Gallium-68 ((68)Ga) is a generator-produced radionuclide with a short half-life (t½ = 68 min) that is particularly well suited for molecular imaging by positron emission tomography (PET). Methods have been developed to synthesize (68)Ga-labeled imaging agents possessing certain drawbacks, such as longer synthesis time because of a required final purification step, the use of organic solvents or concentrated hydrochloric acid (HCl). In our manuscript, we provide a detailed protocol for the use of an advantageous sodium chloride (NaCl)-based method for radiolabeling of chelator-modified peptides for molecular imaging. By working in a lead-shielded hot-cell system,(68)Ga(3+) of the generator eluate is trapped on a cation exchanger cartridge (100 mg, ∼8 mm long and 5 mm diameter) and then eluted with acidified 5 M NaCl solution directly into a sodium acetate-buffered solution containing a DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) or DOTA-like chelator-modified peptide. The main advantages of this procedure are the high efficiency and the absence of organic solvents. It can be applied to a variety of peptides, which are stable in 1 M NaCl solution at a pH value of 3-4 during reaction. After labeling, neutralization, sterile filtration and quality control (instant thin-layer chromatography (iTLC), HPLC and pH), the radiopharmaceutical can be directly administered to patients, without determination of organic solvents, which reduces the overall synthesis-to-release time. This procedure has been adapted easily to automated synthesis modules, which leads to a rapid preparation of (68)Ga radiopharmaceuticals (12-16 min). PMID:27172166

  8. Mechanochemical synthesis of mesoporous tin oxide: a new generation nanosorbent for (68)Ge/(68)Ga generator technology.

    PubMed

    Chakravarty, Rubel; Chakraborty, Sudipta; Shukla, Rakesh; Bahadur, Jitendra; Ram, Ramu; Mazumder, Subhasish; Dev Sarma, Haladhar; Tyagi, Avesh Kumar; Dash, Ashutosh

    2016-09-14

    The present article reports the synthesis and characterization of mesoporous tin oxide (MTO) nanoparticles by a solid-state mechanochemical route. The synthesized material was used as an advanced sorbent material for (68)Ge/(68)Ga radionuclide generator technology. Gallium-68 (t½ = 68 min) obtained from the (68)Ge/(68)Ga generator is an important diagnostic radioisotope which holds tremendous potential in the non-invasive monitoring of various diseases, including cancer, using positron emission tomography (PET). The crystallite size of the MTO nanoparticles was in the range of 6-12 nm with a large surface area of 265 ± 16 m(2) g(-1), while the mean pore radius was found to be 2.1 ± 0.6 nm. Determination of the zeta-potential of the MTO nanoparticles dispersed in solutions at different pH values aided in understanding the sorption and separation mechanisms, which were based on the surface charge developed on the nanosorbent. The sorption capacity observed under column-flow conditions was 85 ± 5 mg Ge per g of nanosorbent. A clinical-scale (68)Ge/(68)Ga generator (740 MBq) was developed using this nanosorbent. Gallium-68 could be regularly eluted from this generator over a prolonged period of 1 year with >70% elution yield and met all the requirements for clinical use. The suitability of (68)Ga obtained from it was evaluated in preclinical settings by the preparation of a (68)Ga-labeled peptide containing the arginine-glycine-aspartic acid (RGD) motif. To the best of our knowledge, this is the first report on the synthesis of MTO nanoparticles by a mechanochemical route which could be effectively utilized for the routine preparation of clinical-scale (68)Ge/(68)Ga generators. The promising results obtained in this study would facilitate greater implementation of mechanochemistry for the synthesis of nanosorbents for radionuclide generator technology since this method is simple, economical and convenient. PMID:27482930

  9. Ileal neuroendocrine tumors and heart: not only valvular consequences.

    PubMed

    Calissendorff, Jan; Maret, Eva; Sundin, Anders; Falhammar, Henrik

    2015-04-01

    Ileal neuroendocrine tumors (NETs) often progress slowly, but because of their generally nonspecific symptoms, they have often metastasized to local lymph nodes and to the liver by the time the patient presents. Biochemically, most of these patients have increased levels of whole blood serotonin, urinary 5-hydroxyindoleacetic acid, and chromogranin A. Imaging work-up generally comprises computed tomography or magnetic resonance imaging and somatostatin receptor scintigraphy, or in recent years positron emission tomography with 68Ga-labeled somatostatin analogs, allowing for detection of even sub-cm lesions. Carcinoid heart disease with affected leaflets, mainly to the right side of the heart, is a well-known complication and patients routinely undergo echocardiography to diagnose and monitor this. Multitasking surgery is currently recognized as first-line treatment for ileal NETs with metastases and carcinoid heart disease. Open heart surgery and valve replacement are advocated in patients with valvular disease and progressive heart failure. When valvulopathy in the tricuspid valve results in right-sided heart failure, a sequential approach, performing valve replacement first before intra-abdominal tumor-reductive procedures are conducted, reduces the risk of bleeding. Metastases to the myocardium from ileal NETs are seen in <1-4.3% of patients, depending partly on the imaging technique used, and are generally discovered in those affected with widespread disease. Systemic treatment with somatostatin analogs, and sometimes alpha interferon, is first-line medical therapy in metastatic disease to relieve hormonal symptoms and stabilize the tumor. This treatment is also indicated when heart metastases are detected, with the addition of diuretics and fluid restriction in cases of heart failure. Myocardial metastases are rarely treated by surgical resection. PMID:25319177

  10. Current and future trends in the anatomic and functional imaging of head and neck paragangliomas

    PubMed Central

    Taïeb, David; Varoquaux, Arthur; Chen, Clara C; Pacak, Karel

    2013-01-01

    Head and neck paragangliomas (HNPGLs) account for approximately 3% of all paragangliomas (PGLs). Most often, HNPGLs are benign, non-secreting, and slowly progressing. The initial physical examination and biochemical diagnosis usually adds very little to the proper diagnosis of these tumors and therefore, radiologists and nuclear medicine physicians play the pivotal role in providing the initial diagnosis, the locoregional staging, and the plan for detecting potential multicentric or metastatic lesions. Based on several current studies, the most accurate use of HNPGL-specific initial and subsequent imaging modalities must be guided by the knowledge of genetics and the specifically measured biochemical profile of these tumors for the proper management of these patients. Thus, this short review article presents the application of the most up-to-date anatomic and functional imaging approaches to HNPGLs tightly linked to the clinical management of these patients. Based on the most recent studies, 18F-FDOPA PET/CT has been shown to be a useful addition to anatomic imaging in the preoperative localization and molecular assessment of HNPGLs. It is estimated that the frequency of metabolically active PGLs on 18F-FDOPA PET/CT in this region is higher than 90%. 18F-FDG PET/CT should be reserved for patients with hereditary PGL syndromes. Imaging of somatostatin receptors using Octreoscan or 68Ga-labeled somatostatin analogs plays an important role for selecting patients for targeted radiation therapy. This review also concludes that it is expected that in the near future, these patients will indeed benefit from new diagnostic approaches based on the identification of new targets by molecular profiling studies that will result in the development of novel PGL specific radiopharamceuticals. PMID:24094713

  11. Development of novel radiogallium-labeled bone imaging agents using oligo-aspartic acid peptides as carriers.

    PubMed

    Ogawa, Kazuma; Ishizaki, Atsushi; Takai, Kenichiro; Kitamura, Yoji; Kiwada, Tatsuto; Shiba, Kazuhiro; Odani, Akira

    2013-01-01

    (68)Ga (T 1/2 = 68 min, a generator-produced nuclide) has great potential as a radionuclide for clinical positron emission tomography (PET). Because poly-glutamic and poly-aspartic acids have high affinity for hydroxyapatite, to develop new bone targeting (68)Ga-labeled bone imaging agents for PET, we used 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) as a chelating site and conjugated aspartic acid peptides of varying lengths. Subsequently, we compared Ga complexes, Ga-DOTA-(Asp)n (n = 2, 5, 8, 11, or 14) with easy-to-handle (67)Ga, with the previously described (67)Ga-DOTA complex conjugated bisphosphonate, (67)Ga-DOTA-Bn-SCN-HBP. After synthesizing DOTA-(Asp)n by a Fmoc-based solid-phase method, complexes were formed with (67)Ga, resulting in (67)Ga-DOTA-(Asp)n with a radiochemical purity of over 95% after HPLC purification. In hydroxyapatite binding assays, the binding rate of (67)Ga-DOTA-(Asp)n increased with the increase in the length of the conjugated aspartate peptide. Moreover, in biodistribution experiments, (67)Ga-DOTA-(Asp)8, (67)Ga-DOTA-(Asp)11, and (67)Ga-DOTA-(Asp)14 showed high accumulation in bone (10.5 ± 1.5, 15.1 ± 2.6, and 12.8 ± 1.7% ID/g, respectively) but were barely observed in other tissues at 60 min after injection. Although bone accumulation of (67)Ga-DOTA-(Asp)n was lower than that of (67)Ga-DOTA-Bn-SCN-HBP, blood clearance of (67)Ga-DOTA-(Asp)n was more rapid. Accordingly, the bone/blood ratios of (67)Ga-DOTA-(Asp)11 and (67)Ga-DOTA-(Asp)14 were comparable with those of (67)Ga-DOTA-Bn-SCN-HBP. In conclusion, these data provide useful insights into the drug design of (68)Ga-PET tracers for the diagnosis of bone disorders, such as bone metastases. PMID:24391942

  12. 68Ga-DOTA-Siglec-9 PET/CT imaging of peri-implant tissue responses and staphylococcal infections

    PubMed Central

    2014-01-01

    Background Staphylococcus epidermidis (S. epidermidis) has emerged as one of the leading pathogens of biomaterial-related infections. Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial molecule controlling extravasation of leukocytes. Sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) is a leukocyte ligand of VAP-1. We hypothesized that 68Ga-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-conjugated Siglec-9 motif containing peptide (68Ga-DOTA-Siglec-9) could detect inflammatory response due to S. epidermidis peri-implant infection by positron emission tomography (PET). Methods Thirty Sprague-Dawley rats were randomized into three groups. A sterile catheter was implanted into the medullary canal of the left tibia. In groups 1 and 2, the implantation was followed by peri-implant injection of S. epidermidis or Staphylococcus aureus (S. aureus) with adjunct injections of aqueous sodium morrhuate. In group 3, sterile saline was injected instead of bacteria and no aqueous sodium morrhuate was used. At 2 weeks after operation, 68Ga-DOTA-Siglec-9 PET coupled with computed tomography (CT) was performed with the measurement of the standardized uptake value (SUV). The presence of the implant-related infection was verified by microbiological analysis, imaging with fluorescence microscope, and histology. The in vivo PET results were verified by ex vivo measurements by gamma counter. Results In group 3, the tibias with implanted sterile catheters showed an increased local uptake of 68Ga-DOTA-Siglec-9 compared with the intact contralateral bones (SUVratio +29.5%). 68Ga-DOTA-Siglec-9 PET detected inflammation induced by S. epidermidis and S. aureus catheter-related bone infections (SUVratio +58.1% and +41.7%, respectively). The tracer uptake was significantly higher in the S. epidermidis group than in group 3 without bacterial inoculation, but the difference between S. epidermidis and S. aureus groups was not statistically

  13. Improved target volume definition for fractionated stereotactic radiotherapy in patients with intracranial meningiomas by correlation of CT, MRI, and [{sup 68}Ga]-DOTATOC-PET

    SciTech Connect

    Milker-Zabel, Stefanie . E-mail: stefanie_milker-zabel@med.uni-heidelberg.de; Zabel-du Bois, Angelika; Henze, Marcus; Huber, Peter; Schulz-Ertner, Daniela; Hoess, Angelika; Haberkorn, Uwe; Debus, Juergen

    2006-05-01

    Purpose: To evaluate the influence of {sup 68}-Ga-labeled DOTA ( )-D-Phe ({sup 1})-Tyr ({sup 3})-Octreotide positron emission tomography ([{sup 68}Ga]-DOTATOC-PET) for target definition for fractionated stereotactic radiotherapy (FSRT) as a complementary modality to computed tomography (CT) and magnetic resonance imaging (MRI). Because meningiomas show a high expression of somatostatin receptor subtype 2, somatostatin analogs such as DOTATOC offer the possibility of receptor-targeted imaging. Patients and Methods: Twenty-six patients received stereotactic CT, MRI, and [{sup 68}Ga]-DOTATOC-PET as part of their treatment planning. Histology was: World Health Organization (WHO) Grade 1 61.5%, WHO Grade 2 7.7%, WHO Grade 3 3.9%, and undetermined 26.9%. Six patients received radiotherapy as primary treatment, 2 after subtotal resection; 17 patients were treated for recurrent disease. Dynamic PET scans were acquired before radiotherapy over 60 min after intravenous injection of 156 {+-} 29 MBq [{sup 68}Ga]-DOTATOC. These PET images were imported in the planning software for FSRT. Planning target volume (PTV)-I outlined on CT and contrast-enhanced MRI was compared with PTV-II outlined on PET. PTV-III was defined with CT, MRI, and PET and was actually used for radiotherapy treatment. Results: PTV-III was smaller than PTV-I in 9 patients, the same size in 7 patients, and larger in 10 patients. Median PTV-I was 49.6 cc, median PTV-III was 57.2 cc. In all patients [{sup 68}Ga]-DOTATOC-PET delivered additional information concerning tumor extension. PTV-III was significantly modified based on DOTATOC-PET data in 19 patients. In 1 patient no tumor was exactly identified on CT/MRI but was visible on PET. Conclusion: These data demonstrate that [{sup 68}Ga]-DOTATOC-PET improves target definition for FSRT in patients with intracranial meningiomas. Radiation targeting with fused DOTATOC-PET, CT, and MRI resulted in significant alterations in target definition in 73%.

  14. Which metabolic imaging, besides bone scan with 99mTc-phosphonates, for detecting and evaluating bone metastases in prostatic cancer patients? An open discussion.

    PubMed

    Bombardieri, E; Setti, L; Kirienko, M; Antunovic, L; Guglielmo, P; Ciocia, G

    2015-12-01

    Prostate cancer bone metastases occur frequently in advanced cancer and this is matter of particular attention, due to the great impact on patient's management and considering that a lot of new emerging therapeutic options have been recently introduced. Imaging bone metastases is essential to localize lesions, to establish their size and number, to study characteristics and changes during therapy. Besides radiological imaging, nuclear medicine modalities can image their features and offer additional information about their metabolic behaviour. They can be classified according to physical characteristics, type of detection, mechanism of uptake, availability for daily use. The physiopathology of metastases formation and the mechanisms of tracer uptake are essential to understand the interpretation of nuclear medicine images. Therefore, radiopharmaceuticals for bone metastases can be classified in agents targeting bone (99mTc-phosphonates, 18F-fluoride) and those targeting prostatic cancer cells (18F-fluoromethylcholine, 11C-choline, 18F-fluorodeoxyglucose). The modalities using the first group of tracers are planar bone scan, SPECT or SPECT/CT with 99mTc-diphosphonates, and 18F-fluoride PET/CT, while the modalities using the second group include 18F/11C-choline derivatives PET/CT, 18F-FDG PET/CT and PET/CT scans with several other radiopharmaceuticals described in the literature, such as 18F/11C-acetate derivatives, 18F-fluoro-5α-dihydrotestosterone (FDHT), 18F-anti-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), 18F-2'-fluoro-5-methyl-1-β-D-arabinofuranosyluracil (FMAU) and 68Ga-labeled-prostate specific membrane antigen (PMSA) PET/TC. However, since data on clinical validation for these last novel modalities are not conclusive and/or are not still sufficient in number, at present they can be still considered as promising tools under evaluation. The present paper considers the nuclear modalities today available for the clinical routine. This overview wants

  15. New radiopharmaceutical agents for the treatment of castration-resistant prostate cancer.

    PubMed

    Maffioli, L; Florimonte, L; Costa, D C; Correia Castanheira, J; Grana, C; Luster, M; Bodei, L; Chinol, M

    2015-12-01

    with positron emitting radionuclides such as 68Ga in order to improve sensitivity and specificity for detecting primary, metastatic, and recurrent PCa by PET/CT over conventional imaging techniques. Although peptide radionuclide ligand therapy studies have just initiated, the diagnostic relevance of 68Ga labeled specific tracers has already been established its clinical utility and represents a valid tool against this common and deadly cancer. PMID:26222274

  16. Imaging integrin alpha-v-beta-3 expression in tumors with an 18F-labeled dimeric RGD peptide

    PubMed Central

    Dijkgraaf, Ingrid; Terry, Samantha; McBride, William J.; Goldenberg, David M.; Laverman, Peter; Franssen, Gerben M.; Oyen, Wim J. G.; Boerman, Otto C.

    2014-01-01

    Integrin αvβ3 receptors are expressed on activated endothelial cells during neovascularization to maintain tumor growth. Many radiolabeled probes utilize the tight and specific association between the arginine-glycine-aspartatic acid (RGD) peptide and integrin αvβ3, but one main obstacle for any clinical application of these probes is the laborious multistep radiosynthesis of 18F. In this study, the dimeric RGD peptide, E-[c(RGDfK)]2, was conjugated with NODAGA and radiolabeled with 18F in a simple one-pot process with a radiolabeling yield of 20%; the whole process lasting only 45 min. NODAGA-E-[c(RGDfK)]2 labeled with 18F at a specific activity of 1.8 MBq/nmol and a radiochemical purity of 100% could be achieved. Log P value of 18F-labeled NODAGA-E-[c(RGDfK)]2 was −4.26 ± 0.02. In biodistribution studies, 18F-NODAGA-E-[c(RGDfK)]2 cleared rapidly from the blood with 0.03 ± 0.01 %ID/g in the blood at 2 h p.i., mainly via the kidneys and showed good in vivo stability. Tumor uptake of 18F-NODAGA-E-[c(RGDfK)]2 (3.44 ± 0.20 %ID/g, 2 h p.i.) was significantly lower than that of reference compounds 68Ga-labeled NODAGA-E-[c(RGDfK)]2 (6.26 ± 0.76 %ID/g; P <0.001) and 111In-labeled NODAGA-E-[c(RGDfK)]2 (4.99 ± 0.64 %ID/g; P < 0.01). Co-injection of an excess of unlabeled NODAGA-E-[c(RGDfK)]2 along with 18F-NODAGA-E-[c(RGDfK)]2 resulted in significantly reduced radioactivity concentrations in the tumor (0.85 ± 0.13 %ID/g). The αvβ3 integrin-expressing SK-RC-52 tumor could be successfully visualized by microPET with 18F-labeled NODAGA-E-[c(RGDfK)]2. In conclusion, NODAGA-E-[c(RGDfK)]2 could be labeled rapidly with 18F using a direct aqueous, one-pot method and it accumulated specifically in αvβ3 integrin-expressing SK-RC-52 tumors, allowing for visualization by microPET. PMID:23606427

  17. IMPROVED RADIATION DOSIMETRY/RISK ESTIMATES TO FACILITATE ENVIRONMENTAL MANAGEMENT OF PLUTONIUM CONTAMINATED SITES

    EPA Science Inventory

    The Office of Environmental Management is the custodian of large quantities of toxic radioactive materials from manufacturing and processing facilities after the United States halted nuclear weapons production. Because these materials include high-specific activity (HSA) and low-...

  18. NREL Team Creates High-Activity, Durable Platinum Extended Surface Catalyst for Fuel Cells (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    Researchers with NREL's Fuel Cell team showed that platinum can replace copper nanowires in such a way that high-surface-area and high-specific-activity catalysts are produced, potentially allowing for lower-cost catalysts.

  19. Aureobasidium pullulans xylanase, gene and signal sequence

    DOEpatents

    Xin-Liang, Li; Ljungdahl, Lars G.

    1997-01-01

    A xylanase from Aureobasidium pullulans having a high specific activity is provided as well as a signal protein for controlling excretion into cell culture medium of proteins to which it is attached. DNA encoding these proteins is also provided.

  20. PET Imaging of Very Late Antigen-4 in Melanoma: Comparison of 68Ga- and 64Cu-Labeled NODAGA and CB-TE1A1P-LLP2A Conjugates

    PubMed Central

    Beaino, Wissam; Anderson, Carolyn J.

    2014-01-01

    were significantly higher for 64Cu-CB-TE1A1P-PEG4-LLP2A than 64Cu-NODAGA-PEG4-LLP2A (all P values < 0.05). PET/CT imaging of metastatic melanoma with 68Ga-NODAGA-PEG4-LLP2A and 64Cu-NODAGA-PEG4-LLP2A showed high uptake of the probes at the site of metastasis, correlating with the bioluminescence imaging of the tumor. Conclusion These data demonstrate that 64Cu-labeled CB-TE1A1P/NODAGA LLP2A conjugates and 68Ga-labeled NODAGA-LLP2A are excellent imaging agents for melanoma and potentially other VLA-4–positive tumors. 64Cu-CB-TE1A1P-PEG4-LLP2A had the most optimal tumor–to–nontarget tissue ratios for translation into humans as a PET imaging agent for melanoma. PMID:25256059

  1. Aureobasidium pullulans xylanase, gene and signal sequence

    DOEpatents

    Li Xinliang; Ljungdahl, L.G.

    1997-01-07

    A xylanase from Aureobasidium pullulans having a high specific activity is provided, as well as a signal protein for controlling excretion into cell culture medium of proteins to which it is attached. DNA encoding these proteins is also provided. 4 figs.

  2. Synthesis of [15, 16- ³H] beta-funaltrexamine.

    PubMed

    Filer, Crist N; Seguin, Richard J

    2013-05-15

    Beta-funaltrexamine is a unique irreversible antagonist for the mu-opiate receptor and would be useful as a tritiated radioligand. Starting from high specific activity [15, 16-³H] naltrexone, [15, 16-³H] beta-funaltrexamine was synthesized and characterized by means of a two-step reductive amination-acylation process. PMID:24285378

  3. Assay for vitamin B12 absorption and method of making labeled vitamin B12

    SciTech Connect

    Anderson, Peter J.; Dueker, Stephen; Miller, Joshua; Green, Ralph; Roth, John; Carkeet, Colleen; Buchholz,; Bruce A.

    2012-06-19

    The invention provides methods for labeling vitamin B12 with .sup.14C, .sup.13C, tritium, and deuterium. When radioisotopes are used, the invention provides for methods of labeling B12 with high specific activity. The invention also provides labeled vitamin B12 compositions made in accordance with the invention.

  4. Thermally Stable Amylases from Antarctic Psychrophilic Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrolysis of starch in cold environments by psychrophilic species of bacteria is believed to be accomplished through the production of special cold-adapted amylases. These amylases are reportedly thermally labile with low (<40 deg C) temperature optima and high specific activities at 0 to 25 deg C....

  5. Tritium waste control: October 1981-March 1982

    SciTech Connect

    Lamberger, P.H.; Rogers, M.L.

    1982-08-16

    Progress reports and summaries are presented for the following: electrolysis of tritiated water; impurity removal from the Combined Electrolysis Catalytic Exchange (CECE) feed water; gas generation measurements on tritiated waste materials; fixation of aqueous tritiated waste in polymer-impregnated concrete; management of high specific activity tritiated liquid wastes; and treatment of tritium contaminated water at Three Mile Island. (ATT)

  6. Synthesis of tritium-labeled vitamin A and its analogs

    SciTech Connect

    Rhee, S.W.; Bubb, J.E.

    1985-11-01

    Metabolic and pharmacologic studies of Vitamin A and its analogs related to the prevention of lung cancer and other epithelial cancers required tritium-labeled Vitamin A analogs and ..beta..-carotene at high specific activity. Syntheses of some of the isomers were therefore developed in the laboratory, as described in the paper. The advantages of the scheme shown are that : 1. Tritiums are introduced into the molecule by catalytic hydrogenation, thus affording high specific activity. 2. It uses an allylic rearrangement of tritiated vinyl-..beta..-ionol to C/sub 15/-phosphonium salt, which is condensed with C/sub 5/-nitrile to give C/sub 20/-skeleton of retinonitrile. 3. It permits the development of milder methods to convert tritium-labeled retinaldehyde, as a common intermediate, to the other retinoids (i.e., retinoic acid, retinol, and retinyl acetate). Furthermore, tritium-labeled all-trans-..beta..-carotene, an important carotenoid, has been obtained from the retinaldehyde.

  7. Future of low specific activity molybdenum-99/technetium-99m generator.

    PubMed

    Mushtaq, A

    2012-10-01

    In last few years, the shortage of molybdenum-99 (99Mo) was felt in the developed and developing countries hospitals, where diagnostic nuclear medicine is practiced. To overcome the shortage of 99Mo various routes of its production by accelerators and reactors generating low and high specific activity products have been planned. High specific activity 99Mo obtained by fission of uranium-235 (235U) has completely dominated in the manufacturing of technetium-99m (99mTc) generators in last 3-4 decades, but due to proliferation and dirty bomb, issues non fission routes of 99Mo production are emphasized. Future of low specific activity 99Mo is discussed. PMID:22642420

  8. Transport of Radioactive Material by Alpha Recoil

    SciTech Connect

    Icenhour, A.S.

    2005-05-19

    The movement of high-specific-activity radioactive particles (i.e., alpha recoil) has been observed and studied since the early 1900s. These studies have been motivated by concerns about containment of radioactivity and the protection of human health. Additionally, studies have investigated the potential advantage of alpha recoil to effect separations of various isotopes. This report provides a review of the observations and results of a number of the studies.

  9. Alchemy with short-lived radionuclides

    SciTech Connect

    Rubio, F.F.; Finn, R.D.; Gilson, A.J.

    1981-04-01

    A variety of short-lived radionuclides are produced and subsequently incorporated into radiopharmaceutical compounds in the radionuclide production program currently being conducted at the Cyclotron Facility of Mount Sinai Medical Center. The recovery of high specific activity oxygen-15 labelled water prepared by means of an inexpensive system operating in conjunction with an on-line radiogas target routinely utilized for oxygen-15 labelled carbon dioxide studies is currently receiving particular attention.

  10. Synthesis and biological evaluation of [125I]- and [123I]-4-iododexetimide, a potent muscarinic cholinergic receptor antagonist.

    PubMed

    Wilson, A A; Dannals, R F; Ravert, H T; Frost, J J; Wagner, H N

    1989-05-01

    A series of halogenated racemic analogues of dexetimide (1) was synthesized and their affinity for the muscarinic cholinergic receptor measured. One analogue, 4-iododexetimide (21), was efficiently labeled with 125I and 123I at high specific activity. In vitro binding studies and in vivo biodistribution studies suggest that 123I-labeled 21 may be useful for imaging muscarinic cholinergic receptors in the living human brain with single photon emission computed tomography. PMID:2785211

  11. Production of the radioactive antitumoral cisplatin.

    PubMed

    Leal, Alexandre S; Carvalho Júnior, Alvaro D; Abrantes, Fabiana M; Menezes, Maria Angela de B C; Ferraz, Vany; Cruz, Tamara S; Cardoso, Valbert N; de Oliveira, Mônica C

    2006-02-01

    This work presents the preparation of radiolabelled cis-dichlorodiammineplatinum (II), CDDP*, sealed in a cadmium capsule. The irradiation of CDDP covered by cadmium, employing exposure times longer than 2 h, demonstrated good chemical purity and high specific activity. This finding allowed a better detection of in vivo CDDP* and suggests that it may be a good tool for studies of long-term biodistribution of pharmaceutical formulations containing this drug. PMID:16099666

  12. Separation of carrier-free holmium-166 from neutron-irradiated dysprosium targets

    SciTech Connect

    Dadachova, E.; Lambrecht, R.M.; Hetherington, E.L. ); Mirzadeh, S.; Knapp, F.F. Jr. )

    1994-12-01

    Holmium-166 ([sup 166]Ho, t[sub 1/2] = 26.4 h) is utilized in radiotherapeutic applications such as radioimmunospecific pharmaceuticals, bone marrow ablation, and radiation synovectomy. High specific activity [sup 166]Ho can be obtained from the decay of dysprosium-166 ([sup 166]Dy, t[sub 1/2] = 81.5 h). Dysprosium-166 is produced by the [sup 164]Dy[n,[gamma

  13. /sup 76/Br-bromospiroperidol: a new tool for quantitative in-vivo imaging of neuroleptic receptors

    SciTech Connect

    Maziere, B.; Loc'h, C.; Hantraye, P.; Guillon, R.; Duquesnoy, N.; Soussaline, F.; Naquet, R.; Comar, D.; Maziere, M.

    1984-09-24

    Bromine-76 labeled bromospiperone has been prepared with a very high specific activity (>1 Ci/..mu..mole). In-vivo studies in rat correborated by PET studies in baboon have shown that the regional concentration of this radioligand parallels the morphologic distribution of dopamine receptors and that its binding in the striatum is saturable and displaceable. Tomographic images show a clear delineation of the stratial region 2.5 hours after administration of the radioligand.

  14. Novel thermostable endo-xylanase cloned and expressed from bacterium Geobacillus sp. WSUCF1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A gene encoding a GH10 endo-xylanase from Geobacillus sp. WSUCF1 was cloned and expressed in Escherichia coli. Recombinant endo-xylanase (37 kDa) exhibited high specific activity of 461.0 U/ mg of protein. Endo-xylanase was optimally active on birchwood xylan at 70°C and pH 6.5. Zn2+ and Ca2+ ions i...

  15. Insect Ryanodine Receptor: Distinct But Coupled Insecticide Binding Sites for [N-C3H3]Chlorantraniliprole, Flubendiamide, and [3H]Ryanodine

    PubMed Central

    Isaacs, André K.; Qi, Suzhen; Sarpong, Richmond; Casida, John E.

    2015-01-01

    Radiolabeled anthranilic diamide insecticide [N-C3H3]chlorantraniliprole was synthesized at high specific activity and compared with phthalic diamide insecticide flubendiamide and [3H]ryanodine in radioligand binding studies with house fly muscle membranes to provide the first direct evidence with a native insect ryanodine receptor that the major anthranilic and phthalic diamide insecticides bind at different allosterically coupled sites, i.e. there are three distinct Ca2+-release channel targets for insecticide action. PMID:22856329

  16. Lessons Learned from In Vivo Studies of a Viral Noncoding RNA

    PubMed Central

    Kincaid, Rodney P.

    2016-01-01

    ABSTRACT Despite increasing interest in the biology of noncoding RNAs (ncRNAs), few functions have been uncovered for viral ncRNAs in vivo. In their recent article in mSphere, Feldman and colleagues [E. R. Feldman et al., mSphere 1(2):e00105-15, 2016, doi:10.1128/mSphere.00105-15] demonstrate a highly specific activity of a gammaherpesviral ncRNA in viral dissemination and establishment of latent infection. Their work highlights several interesting features that should be informative to future studies of viral ncRNA. PMID:27301787

  17. Reactions of human and hog intrinsic factors with type I antibody to intrinsic factor

    PubMed Central

    Gullberg, R.

    1970-01-01

    A simple and rapid small-scale gel filtration method was applied in studies of type I antibody to intrinsic factor using radioactive vitamin B12 of high specific activity and purified human and hog intrinsic factor preparations, taking into account the unsaturated B12-binding capacity of the individual pernicious anaemia sera. This procedure allows the use of small amounts of reagents. Evidence was obtained for a close antigenic similarity of determinants of human and hog intrinsic factor. The use of purified intrinsic-factor preparations is important. PMID:4097742

  18. Synthesis of carrier-free tritium-labeled queen bee pheromone

    SciTech Connect

    Webster, F.X.; Prestwich, G.D.

    1988-03-01

    A short synthesis of (4,5-/sup 3/H/sub 2/) (E)-9-oxo-2-decenoic acid (ODA), a high-specific-activity tritium-containing isotopomer of the queen bee pheromone, is described. Catalytic tritiation of the ketal of ethyl 9-oxo-4-decenoate introduces tritium into two positions, one of which is completely unactivated. Subsequent transformation by selenation, oxidation, and hydrolysis affords the labeled 9-ODA at >60 Ci/mmol. The material is suitable for biochemical studies of binding and catabolism in ovarian, antennal, and other target tissues.

  19. Properties of liposomes containing 212Pb.

    PubMed

    Rosenow, M K; Zucchini, G L; Bridwell, P M; Stuart, F P; Friedman, A M

    1983-01-01

    The reverse phase evaporation method was used to prepare lipid bilayer membrane vesicles containing 212Pb and other markers of high specific activity. Electron microscopy and microfiltration were used to measure the sizes of the liposomes. Isotopes were released from the liposomes during exposure to serum and this leakage was prevented by complexing of small molecules with proteins or by precipitating particulate complexes within the liposomes. The in vivo distribution of 212Pb liposomes differed from the distribution of free 212Pb in that the reticuloendothelial system cleared the liposomes. Liposomes with surface dinitrophenol hapten were highly immunogenic and the humoral response to dinitrophenol was nonspecifically suppressed by 212Pb liposomes. PMID:6363323

  20. Radiosynthesis of [18F]3-acetylcyclofoxy: a high affinity opiate antagonist.

    PubMed

    Channing, M A; Eckelman, W C; Bennett, J M; Burke, T R; Rice, K C

    1985-06-01

    A convenient method for the preparation of high specific activity [18F]3-acetylcyclofoxy (3-acetyl-6-deoxy-6-beta-18F-fluoronaltrexone) was developed. The method utilizes reactor-produced [18F]-fluoride as its tetraethylammonium (TEA X F) salt in a SN2 displacement on a secondary triflate precursor. Typically, 45% of the 18F activity can be converted to the reactive TEAF in a 70 min preparation. From this, 35% yield (decay corrected) of the [18F]3-acetylcyclofoxy was obtained after HPLC purification with a specific activity of 25 Ci/mmol in a total synthesis time of 60 min. PMID:2993171

  1. Environmental fate of five radio-labeled coal conversion by-products evaluated in a laboratory model ecosystem

    PubMed Central

    Lu, Po-Yung; Metcalf, Robert L.; Carlson, Elaine M.

    1978-01-01

    Anthracene, fluorene, carbazole, dibenzofuran, and dibenzothiophene are five typical by-products of coal conversion which are likely to be environmental pollutants. These were radiolabeled to high specific activity and purity by simple tritium exchange and evaluated for environmental fate in laboratory model ecosystems. Anthracene and fluorene were biologically converted to hydroxy and keto analogs. Carbazole was N-methylated and N-acetylated. Dibenzothiophene was microsomally oxidized to the sulfoxide and sulfone. Dibenzofuran was relatively inert to biodegradation. The octanol/water partition coefficient for the parent compounds was well correlated with ecological magnification indicating the possibility of predicting environmental behavior from physicochemical parameters. PMID:17539148

  2. Copper-62 labeled ReCCMSH peptide analogs for melanoma PET imaging.

    PubMed

    Zhang, Xiuli; Yue, Zhiwei; Lu, Bao-Yuan; Vazquez-Flores, Gerson J; Yuen, Johnny; Figueroa, Said Daibes; Gallazzi, Fabio; Cutler, Cathy; Quinn, Thomas P; Lacy, Jeffrey L

    2012-10-01

    High-specific activity radiolabeled melanocortin peptide preparations are necessary for optimal melanoma imaging due to the relatively low number of melanocortin-1 receptors (MC1-Rs) per tumor cell. In this study, a one-step synthesis of 62Cu-labeled MC1-R targeting peptide Re(Arg11)CCMSH was developed, which yielded high specific activity radiolabeled peptide preparations that required no post-labeling purification. DOTA and NOTA conjugated Re(Arg11)CCMSH peptides were synthesized and examined for 62Cu radiolabeling and cell binding properties. Biodistribution and PET imaging studies were performed to assess the in vivo tumor targeting and imaging characteristics of the optimal radiolabeled peptide. Melanoma cell binding affinities for NOTA-, NOTA-GGG-, and NOTA-GSG- conjugated Re(Arg11)CCMSH were determined to be 1.3×10-9 M, 1.9×10-9 M and 6.0×10-9 M. The 62Cu radiolabeling efficiencies of DOTA- and NOTA- conjugated Re(Arg11)CCMSH analogs were 30% and > 98% after 2 min at 24° C, while 0.5 μg of NOTA-GGG-peptide could be labeled to > 95% with a maximum specific activity of 138 Ci/μmol. Tumor uptake of 62Cu- NOTA-GGG-Re(Arg11)CCMSH in B16/F1 melanoma bearing mice was 4.65±0.48% ID/g and 9.43±2.69% ID/g at 20 and 40 min post injection and was visualized by PET imaging. High specific activity 62Cu-NOTA-GGG-Re(Arg11)CCMSH was prepared in a one-step procedure at 24°C in 6 min. 62Cu-NOTA-GGG-Re(Arg11)CCMSH exhibited MC1-R selective binding and rapid tumor uptake in B16/F1 melanoma bearing mice that was confirmed by PET imaging studies. High specific activity 62Cu from a 62Zn/62Cu generator coupled with simple one step radiolabeling procedures makes 62Cu an attractive radionuclide for PET imaging of low-density receptor targets. PMID:22724422

  3. Synthesis and characterization of multiply-tyrosinated, multiply-iodinated somatostatin analogs

    SciTech Connect

    Woltering, E A.; O'Dorisio, M S.; Murphy, W A.; Chen, F; Drouant, G J.; Espenan, G D.; Fisher, Darrell R.; Sharma, C; Diaco, D S.; Maloney, T M.; Fuselier, J A.; Nelson, J A.; O'Dorisio, T M.; Coy, D H.

    1999-02-01

    Radio-labeled somatostatin analogs have recently gained popularity as agents useful in intraoperative tumor localization, external scintigraphy and in situ radiotherapy. We have synthesized and characterized a series of novel N-terminally extended multiply-tyrosinated somatostatin analogs that possess high binding affinity for somatostatin receptors, exhibit biological activity comparable to the native peptide and retain these characteristics after iodination. These analogs can be radio-iodinated to high specific activities. Following radio-iodination, these analogs exhibit minimal radiolysis and may be clinically useful for tumor localization, scanning and therapy.

  4. The detection of tritium-labeled ligands and their carrier proteins using a multiwire proportional counter

    SciTech Connect

    Scott, B.J.; Bateman, J.E.; Bradwell, A.R.

    1982-06-01

    Two-dimensional immunoelectrophoresis combined with autoradiography is a powerful technique for studying the binding of radiolabeled ligands to their carrier proteins. Tritium-labeled compounds are difficult to detect by autoradiography, yet this isotope is often the radiolabel of choice, because it is possible to achieve high specific activity with no loss of biological function. Therefore an electronic detection system called a multiwire proportional counter has been investigated. This has resulted in an increase in detection speed for tritium of several thousand fold over conventional autoradiography and furthermore the results are potentially quantitative.

  5. A high intensity positron beam at the Brookhaven reactor

    SciTech Connect

    Weber, M.; Lynn, K.G.; Roellig, L.O.; Mills, A.P. Jr.; Moodenbaugh, A.R.

    1987-01-01

    We describe a high intensity, low energy positron beam utilizing high specific activity /sup 64/Cu sources (870 Ci/g) produced in a reactor with high thermal neutron flux. Fast-to-slow moderation can be performed in a self moderation mode or with a transmission moderator. Slow positron rates up to 1.6 x 10/sup 8/ e/sup +//s with a half life of 12.8 h are calculated. Up to 1.0 x 10/sup 8/ e/sup +//s have been observed. New developments including a Ne moderator and an on-line isotope separation process are discussed. 21 refs., 9 figs.

  6. Fluctuating Electric Field Gradients at 111Cd in Ice

    NASA Astrophysics Data System (ADS)

    Akselrod, Z. Z.; Filossofov, D. V.; Kochetov, O. I.; Korolev, N. A.; Lebedev, N. A.; Milanov, M.; Novgorodov, A. F.; Shirani, E. N.; Timkin, V. V.; Velichkov, A. I.

    2001-11-01

    111Cd PAC measurements have been made using the high specific activity of 111In in the methanol water mixtures of various concentrations at the room temperature. These experiments revealed that the perturbation factors (integrated over two mean lives τN) do not follow the dependence of the macroscopic viscosity η. The observed dynamic character of the PAC spectra in ice is explained by the mobility of orientational and ionic defects. The activation energy for the diffusion process was determined to be E a =0.35(1) eV.

  7. [Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast]. Progress report

    SciTech Connect

    Katzenellenbogen, J.A.

    1991-12-31

    The specific aims of the previous grant application can be summarized as follows: Synthesize fluorine-substituted progestins from the following high affinity classes: R5020 (promegestone), norgestrel, RU486, and retroprogestins; Synthesize fluorine-substituted androgens from the following high affinity classes: mibolerone, R1881 (metribolone) and 2-oxometribolone; Evaluate the receptor binding and non-specific binding of these fluorosteroids by in vitro binding assays; Develop and optimize fluoride ion substitution reactions suitable for the rapid, efficient and convenient preparation of these fluorosteroids in high specific activity, F-18 labeled form; and Evaluate the target tissue uptake of the F-18 labeled androgens and progestins in experimental animals.

  8. (Radiolabeled androgens and progestins as imaging agents for tumors of the prostate and breast)

    SciTech Connect

    Katzenellenbogen, J.A.

    1991-01-01

    The specific aims of the previous grant application can be summarized as follows: Synthesize fluorine-substituted progestins from the following high affinity classes: R5020 (promegestone), norgestrel, RU486, and retroprogestins; Synthesize fluorine-substituted androgens from the following high affinity classes: mibolerone, R1881 (metribolone) and 2-oxometribolone; Evaluate the receptor binding and non-specific binding of these fluorosteroids by in vitro binding assays; Develop and optimize fluoride ion substitution reactions suitable for the rapid, efficient and convenient preparation of these fluorosteroids in high specific activity, F-18 labeled form; and Evaluate the target tissue uptake of the F-18 labeled androgens and progestins in experimental animals.

  9. Production and in vivo imaging of (203)Pb as a surrogate isotope for in vivo (212)Pb internal absorbed dose studies.

    PubMed

    Máthé, Domokos; Szigeti, Krisztián; Hegedűs, Nikolett; Horváth, Ildikó; Veres, Dániel S; Kovács, Béla; Szűcs, Zoltán

    2016-08-01

    (212)Pb is a clinically relevant therapeutic alpha emitter isotope. A surrogate, (203)Pb, if prepared with sufficiently high specific activity could be used to estimate (212)Pb in vivo absorbed doses. An improved production procedure of (203)Pb with a simple, new separation method and high specific radioactivity for imaging is reported. We determined the in-vivo biodistribution of (203)Pb in mice by SPECT/CT. This highlights application possibilities of (203)Pb for further in vivo and clinical uses (radiolabeled (212)Pb-peptide co-injection, dosimetry calculation). PMID:27156049

  10. .sup.18 F-4-Fluoroantipyrine

    DOEpatents

    Shiue, Chyng-Yann; Wolf, Alfred P.

    1984-03-13

    The novel radioactive compound .sup.18 F-4-fluoroantipyrine having high specific activity which can be used in nuclear medicine in diagnostic applications, prepared by the direct fluorination of antipyrine in acetic acid with radioactive fluorine at room temperature and purifying said radioactive compound by means of gel chromatography with ethyl acetate as eluent is disclosed. The non-radioactive 4-fluoroantipyrine can also be prepared by the direct fluorination of antipyrine in acetic acid with molecular fluorine at room temperature and purified by means of gel chromotography with ethyl acetate eluent.

  11. Production of 35S for a Liquid Semiconductor Betavoltaic

    SciTech Connect

    Meier, David E.; Garnov, A. Y.; Robertson, J. D.; Kwon, J. W.; Wacharasindhu, T.

    2009-10-01

    The specific energy density from radioactive decay is five to six orders of magnitude greater than the specific energy density in conventional chemical battery and fuel cell technologies. We are currently investigating the use of liquid semiconductor based betavoltaics as a way to directly convert the energy of radioactive decay into electrical power and potentially avoid the radiation damage that occurs in solid state semiconductor devices due to non-ionizing energy loss. Sulfur-35 was selected as the isotope for the liquid semiconductor demonstrations because it can be produced in high specific activity and it is chemically compatible with known liquid semiconductor media.

  12. Isolation and characterization of a microbial Arg/Lys carboxypeptidase, carboxypeptidase F.

    PubMed

    Matsumura, E; Sato, T; Toyoda, N

    1995-03-01

    Carboxypeptidase F was isolated from a fungal strain F-33 and characterized. The enzyme has the ability to release arginine and lysine from the carboxy terminus of peptides, and showed high specific activity against arginine (140 units mg-1 protein). Optimal temperature and pH for the enzyme reaction were 55 degrees C and pH 8.5, respectively. The enzyme possessed a high thermal stability. Native molecular weight was estimated to be approximately 450,000. Enzymatic activity was inhibited by Co2+, Cd2+, chelating agents and thiol inhibitors. PMID:7766072

  13. /sup 18/F-4-fluoroantipyrine

    SciTech Connect

    Shiue, C.Y.; Wolf, A.P.

    1980-01-01

    The novel radioactive compound /sup 18/F-4-fluoroantipyrine having high specific activity which can be used in nuclear medicine in diagnostic applications, prepared by the direct fluorination of antipyrine in acetic acid with radioactive fluorine at room temperature and purifying said radioactive compound by means of gel chromatography with ethyl acetate as eluent is disclosed. The non-radioactive 4-fluoroantipyrine can also be prepared by the direct fluorination of antipyrine in acetic acid with molecular fluorine at room temperature and purified by means of gel chromatography with ethyl acetate eluent.

  14. Biokinetics of sup 237 Pu citrate and nitrate in the rat: Implications for Pu studies in man

    SciTech Connect

    Talbot, R.J.; Knight, D.A.; Morgan, A. )

    1990-08-01

    Plutonium-237 decays mainly by electron capture with a half-life of 45 d. Alpha particles are emitted in only 5 x 10(-3)% of its disintegrations. This nuclide can now be produced with relatively small amounts of alpha-emitting contaminants so that, in principle, {sup 237}Pu can be used for studies of Pu biokinetics in man. However, because of its high specific activity, there was some doubt that its metabolism would be the same as that of the alpha- and beta-emitting isotopes of Pu normally encountered in the nuclear industry. In this study, the biokinetics of nearly pure, high specific activity {sup 237}Pu are compared with those of lower specific activity, impure {sup 237}Pu containing significant amounts of alpha-emitting Pu, following administration to rats by intravenous injection as the citrate. Both the distribution and excretion of the pure and impure {sup 237}Pu used in the two studies were similar and also in good agreement with the results of previously reported studies using {sup 239}Pu and {sup 241}Pu citrate, thus validating the use of {sup 237}Pu for studies of Pu metabolism in man. Data on the biokinetics of {sup 237}Pu nitrate are also included.

  15. Rapid, high-resolution in situ hybridization histochemistry with radioiodinated synthetic oligonucleotides

    SciTech Connect

    Lewis, M.E.; Arentzen, R.; Baldino, F. Jr.

    1986-01-01

    In situ hybridization histochemistry is a valuable technique for localizing specific messenger RNA (mRNA) and detecting changes in gene expression. Generally, the mRNA of interest has been detected by probes obtained from cloned DNA and labelled to high specific activity by nick translation. Such probes have a number of disadvantages which can be circumvented by the use of short synthetic oligonucleotides designed to be complementary to a known mRNA sequence. We report here that synthetic oligonucleotides complementary to part of the mRNA coding for rat arginine-vasopressin (AVP) can be labelled to high specific activity with (/sup 125/I), using either the primer extension method with the Klenow fragment of DNA polymerase I or the 3'-tailing method with terminal deoxynucleotidyl transferase. Both AVP probes hybridized well to the magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei. A strong autoradiographic signal was present by 2 days, with grains largely confined to the perikaryon. These results compare favorably to those obtained with (/sup 32/P)- or (/sup 3/H)-labelled probes. Given the ease of the 3'-tailing method, (/sup 125/I)-labelled oligonucleotides appear to be especially useful probes for in situ hybridization histochemistry.

  16. Lability of DNA polymerase alpha correlated with decreased DNA synthesis and increased age in human cells

    SciTech Connect

    Busbee, D.; Sylvia, V.; Stec, J.; Cernosek, Z.; Norman, J.

    1987-12-01

    DNA excision repair and mitogen-initiated blastogenesis in human cells declined in efficiency as an apparent function of decreased DNA polymerase alpha specific activity with increased age of the cell donor. DNA polymerase alpha isolated from fetal cells contained a single, high-specific-activity enzyme form that could not be further activated and that was stable with regard to enzyme activity and affinity for DNA template-primer. DNA polymerase alpha isolated from adult-derived cells contained both low-specific-activity and high-specific-activity forms. The low-activity enzyme form, which showed low affinity of binding to DNA template-primer, was activated by treatment with phosphatidylinositol, /sup 32/P-ATP, and phosphatidylinositol kinase, resulting in a /sup 32/P-labeled enzyme that exhibited high affinity of binding to DNA template-primer. The activated enzyme was unstable, exhibiting a loss of /sup 32/P-label correlated with the loss of both specific activity and high affinity of binding to DNA template-primer. The data suggest that DNA polymerase alpha isolated from adult-derived human cells has low-activity and high-activity forms. Decreased specific activity of DNA polymerase alpha correlated with increased age of the donor appears to be a function of loss of an enzyme activator molecule resulting in diminished ability of the enzyme to bind DNA template-primer.

  17. Mono(pyridine-N-oxide) DOTA analog and its G1/G4-PAMAM dendrimer conjugates labeled with 177Lu: radiolabeling and biodistribution studies.

    PubMed

    Laznickova, A; Biricova, V; Laznicek, M; Hermann, P

    2014-02-01

    (177)Lu radiolabeling of the first (G1-) or fourth (G4-) generation polyaminoamide (PAMAM) dendrimer conjugates with DOTA-like bifunctional chelator with one methylenepyridine-N-oxide pendant arm (DO3A-py(NO-C)) stability of the radiolabeled species and their pharmacokinetic characteristics were evaluated in preclinical experiments. The results showed that the G1- and G4-dendrimer conjugates, modified in average with 7.5 or 57 DO3A-py(NO-C) chelating units, respectively, can also be labeled with (177)Lu with a high specific activity and radiochemical purity even at 37 °C. The radiolabeled species were stable for at least 24h. Distribution profile of G1-dendrimer conjugate in organs and tissues of rats was more favorable than that of G4 one. On the other hand, the later dendrimer conjugate bears a substantially higher number of metal chelators per molecule enabling binding of a considerably larger number of radiometals. Our results indicate that an employment of dendrimer-chelate conjugates with bound radiometals might represent a prospective way for radiolabeling of biologically active target-specific macromolecules to obtain markedly high specific activity. PMID:24333746

  18. Microfluidic Radiometal Labeling Systems for Biomolecules

    SciTech Connect

    Reichert, D E; Kenis, P J. A.

    2011-12-29

    In a typical labeling procedure with radiometals, such as Cu-64 and Ga-68; a very large (~ 100-fold) excess of the non-radioactive reactant (precursor) is used to promote rapid and efficient incorporation of the radioisotope into the PET imaging agent. In order to achieve high specific activities, careful control of reaction conditions and extensive chromatographic purifications are required in order to separate the labeled compounds from the cold precursors. Here we propose a microfluidic approach to overcome these problems, and achieve high specific activities in a more convenient, semi-automated fashion and faster time frame. Microfluidic reactors, consisting of a network of micron-sized channels (typical dimensions in the range 10 - 300¼m), filters, separation columns, electrodes and reaction loops/chambers etched onto a solid substrate, are now emerging as an extremely useful technology for the intensification and miniaturization of chemical processes. The ability to manipulate, process and analyze reagent concentrations and reaction interfaces in both space and time within the channel network of a microreactor provides the fine level of reaction control that is desirable in PET radiochemistry practice. These factors can bring radiometal labeling, specifically the preparation of radio-labeled biomolecules such as antibodies, much closer to their theoretical maximum specific activities.

  19. Isolation of chloroplastic phosphoglycerate kinase

    SciTech Connect

    Macioszek, J.; Anderson, L.E. ); Anderson, J.B. )

    1990-09-01

    We report here a method for the isolation of high specific activity phosphoglycerate kinase (EC 2.7.2.3) from chloroplasts. The enzyme has been purified over 200-fold from pea (Pisum sativum L.) stromal extracts to apparent homogeneity with 23% recovery. Negative cooperativity is observed with the two enzyme phosphoglycerate kinase/glyceraldehyde-3-P dehydrogenase (EC 1.2.1.13) couple restored from the purified enzymes when NADPH is the reducing pyridine nucleotide, consistent with earlier results obtained with crude chloroplastic extracts. Michaelis Menten kinetics are observed when 3-phosphoglycerate is held constant and phosphoglycerate kinase is varied, which suggests that phosphoglycerate kinase-bound 1,3-bisphosphoglycerate may be the preferred substrate for glyceraldehyde-3-P dehydrogenase in the chloroplast.

  20. Design of a target system for producing clinically useful quantities of oxygen-15 using an electron linear accelerator.

    PubMed

    Piltingsrud, H V

    1982-01-01

    The nuclear medicine uses of short-lived positron emitters, such as 15O and 11C, rely primarily on the cyclotron production of these radionuclides. This paper presents an alternate approach to production of 15O by the use of photonuclear reactions on 16O, using bremsstrahlung radiation produced by an electron linear accelerator. Methods are described which produce useable quantities of relatively high specific activity 15O (25.1 mCi/4 min at 27.9 Ci/g), using a reboiling H2O target, with an electron linear accelerator having an electron beam energy of 26 MeV and a beam current of 100 microamperemeter. Results of this target system are compared to those of a target system developed recently by other investigators. PMID:7110082

  1. Bismuth-213 and actinium-225 -- generator performance and evolving therapeutic applications of two generator-derived alpha-emitting radioisotopes.

    PubMed

    Morgenstern, Alfred; Bruchertseifer, Frank; Apostolidis, Christos

    2012-07-01

    The alpha emitters (225)Ac and (213)Bi are promising therapeutic radionuclides for application in targeted alpha therapy of cancer and infectious diseases. Both alpha emitters are available with high specific activity from established radionuclide generators. Their favourable chemical and physical properties have led to the conduction of a large number of preclinical studies and several clinical trials, demonstrating the feasibility, safety and therapeutic efficacy of targeted alpha therapy with (225)Ac and (213)Bi. This review describes methods for the production of (225)Ac and (213)Bi and gives an overview of (225)Ac/(213)Bi radionuclide generator systems. Selected preclinical studies are highlighted and the current clinical experience with (225)Ac and (213)Bi is summarized. PMID:22642390

  2. [Catalase and superoxide dismutase in the cells of strictly anaerobic microorganisms].

    PubMed

    Briukhanov, A L; Thauer, R K; Netrusov, A I

    2002-01-01

    Strictly anaerobic microorganisms relating to various physiological groups were screened for catalase and superoxide dismutase (SOD) activity. All of the investigated anaerobes possessed the SOD activity, necessary for protection against toxic products of oxygen reduction. High specific activities of SOD were found in Acetobacterium woodii and Acetobacterium wieringae. Most of the investigated clostridia and acetogens were catalase-negative. A significant activity of catalase was found in Thermohydrogenium kirishiense, in representatives of the genus Desulfotomaculum, and in several methanogens. Methanobrevibacter arboriphilus had an exceptionally high catalase activity after growth in medium supplemented with hemin. Hemin also produced a strong positive effect on the catalase activity in many other anaerobic microorganisms. In methanogens, the activities of the enzymes of antioxidant defense varied in wide ranges depending on the stage of growth and the energy source. PMID:12138753

  3. Signaling role of phospholipid hydroperoxide glutathione peroxidase (PHGPX) accompanying sensing of NaCl stress in etiolated sunflower seedling cotyledons

    PubMed Central

    Jain, Prachi; Bhatla, Satish C

    2014-01-01

    Sunflower seedlings subjected to 120 mM NaCl stress exhibit high total peroxidase activity, differential expression of its isoforms and accumulation of lipid hydroperoxides. This coincides with high specific activity of phospholipid hydroperoxide glutathione peroxidase (PHGPX) in the 10,000g supernatant from the homogenates of 2–6 d old seedling cotyledons. An upregulation of PHGPX activity by NaCl is evident from Western blot analysis. Confocal laser scanning microscopic (CLSM) analysis of sections of cotyledons incubated with anti-GPX4 (PHGPX) antibody highlights an enhanced cytosolic accumulation of PHGPX, particularly around the secretory canals. Present work, thus, highlights sensing of NaCl stress in sunflower seedlings in relation with lipid hydroperoxide accumulation and its scavenging through an upregulation of PHGPX activity in the cotyledons. PMID:25517199

  4. Synthesis and characterization of [N-methyl-3H]loperamide.

    PubMed

    Filer, Crist N; Egan, Judith A; Nugent, Richard P

    2014-05-30

    Loperamide is a piperidine butyramide mu-opiate receptor agonist and currently employed to treat diarrhea. Because a single past report of tritiating loperamide was limited to only a very low specific activity product without technical details or extensive analysis, the synthesis of [N-methyl-(3)H]loperamide at high specific activity is now described in detail. An imine precursor was alkylated with [(3)H]methyl iodide to obtain a quaternary intermediate, which was then reacted with 4-(4-chlorophenyl)-4-hydroxypiperidine to afford the desired product [N-methyl-(3)H]loperamide, characterized by thin layer chromatography (TLC), HPLC, MS, UV, and proton-decoupled tritium NMR. PMID:24753311

  5. Recovery and purification of nickel-63 from HFIR-irradiated targets

    SciTech Connect

    Williams, D.F.; O'Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.

    1993-06-01

    The production of large quantities of high-specific-activity [sup 63]Ni (>10 Ci/g) requires both a highly enriched [sup 62]Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at [sup 51]Cr, and scandium, present as [sup 46]Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.

  6. Bioengineering of the model lantibiotic nisin

    PubMed Central

    Field, Des; Cotter, Paul D; Ross, R Paul; Hill, Colin

    2015-01-01

    The lantibiotics are a class of bacterially produced antimicrobial peptides (bacteriocins) that contain several unusual amino acids resulting from enzyme-mediated post-translational modifications. They exhibit high specific activity against Gram-positive targets, including many antibiotic-resistant pathogens, and consequently have been investigated with a view to their application as antimicrobials in both the food and medical arenas. Importantly, the gene-encoded nature of lantibiotics makes them more amenable to bioengineering strategies to further enhance their antimicrobial and physicochemical properties. However, although the bioengineering of lantibiotics has been underway for over 2 decades, significant progress has only been reported in recent years. This review charts recent developments with regard to the implementation of bioengineering strategies to enhance the functional characteristics of the prototypical and most studied lantibiotic nisin. PMID:25970137

  7. Bioengineering of the model lantibiotic nisin.

    PubMed

    Field, Des; Cotter, Paul D; Ross, R Paul; Hill, Colin

    2015-01-01

    The lantibiotics are a class of bacterially produced antimicrobial peptides (bacteriocins) that contain several unusual amino acids resulting from enzyme-mediated post-translational modifications. They exhibit high specific activity against Gram-positive targets, including many antibiotic-resistant pathogens, and consequently have been investigated with a view to their application as antimicrobials in both the food and medical arenas. Importantly, the gene-encoded nature of lantibiotics makes them more amenable to bioengineering strategies to further enhance their antimicrobial and physicochemical properties. However, although the bioengineering of lantibiotics has been underway for over 2 decades, significant progress has only been reported in recent years. This review charts recent developments with regard to the implementation of bioengineering strategies to enhance the functional characteristics of the prototypical and most studied lantibiotic nisin. PMID:25970137

  8. (I-125) 17. cap alpha. -Iodovinyl 11. beta. -methoxyestradiol: in vivo and in vitro properties of a high-affinity estrogen-receptor radiopharmaceutical

    SciTech Connect

    Jagoda, E.M.; Gibson, R.E.; Goodgold, H.; Ferreira, N.; Francis, B.E.; Reba, R.C.; Rzeszotarski, W.J.; Eckelman, W.C.

    1984-04-01

    17 ..cap alpha..-(/sup 125/I)Iodovinyl 11 ..beta..-methoxyestradiol ((I-125)MIVE/sub 2/) has been prepared with high specific activity (155-2000 Ci/mmol) and a high affinity for the estrogen receptor. In vivo distribution studies using immature rats result in high levels of activity in the uterus (20-30% dose/g) with uterus-to-plasma ratios on the order of 68 to 100. Peak activity in the uterus is obtained between 2 and 4 hr, and by 6 hr 50% of the activity has washed out. The radioactive labeling of MIVE/sub 2/ is sufficiently rapid so that (I-123)MIVE/sub 2/ has been synthesized and is currently in clinical trials. These results suggest that MIVE/sub 2/ would be an excellent agent for the study of estrogen receptors in vivo and in vitro.

  9. Correspondence between immunological and functional domains in the transforming protein of Fujinami sarcoma virus.

    PubMed Central

    Stone, J C; Pawson, T

    1985-01-01

    Monoclonal antibodies reactive with either gag or fps portions of the wild-type Fujinami sarcoma virus transforming protein have been used to probe the structure of proteins encoded by mutant genomes constructed in vitro. The pattern of immunoreactivity suggests that the functional domain defined in genetic studies (Stone et al., Cell 37:549-558, 1984) corresponds to a discrete immunological domain in the native, wild-type Fujinami sarcoma virus protein. At least one mutation affecting both the structure and function of the proposed NH2-terminal fps-specific domain encodes a product with high specific activities in kinase assays. Furthermore, a cell line expressing high levels of this mutant protein is only moderately transformed. The striking correspondence between the immunological domain defined here and the functional domain inferred from the results of transfection experiments suggests that this non-kinase-specifying region constitutes a discrete structural as well as functional component of the viral protein. Images PMID:2991592

  10. Considerations on /sup 131/I-metaiodobenzylguanidine therapy of six children with neuroblastoma

    SciTech Connect

    Sanguineti, M.

    1987-01-01

    Six children affected by neuroblastoma at stages III and IV were treated with high-specific-activity /sup 131/I-metaiodobenzylguanidine (MIBG). After /sup 131/I-MIBG treatment three patients died at 12, 10, and 12 weeks, respectively; the other three were still living at 21, 16, and 24 weeks, respectively. Although the assumptions for this therapy were propitious, the results obtained do not correspond to those expected. It is supposed that large tumor volume and previous chemotherapy and/or radiotherapy may impair the effectiveness of /sup 131/I-MIBG therapy. Consequently, /sup 131/I-MIBG therapy is recommended even if the spread of disease is not proven-only, however, when the tumor is small.

  11. Hypochlorite radioiodination of parathyroid peptides (hPTH1-34, (Tyr43)hPTH44-68)

    SciTech Connect

    Orwoll, E.; Kopel, A.; Opsahl, Z.; Roberts, L.; Endres, D.; McClung, M.

    1985-02-01

    Parathyroid hormone (PTH) radioimmunoassays have conventionally utilized (/sup 125/I)bPTH1-84 as a radioligand, but more region-specific PTH assays are now possible with the use of recently available synthetic PTH peptides as standards and radioligands. A radioiodination procedure has been developed that utilizes hypochlorite as an oxidant and that is capable of producing PTH tracers of high specific activity (200 to 250 microCi/micrograms), prolonged stability, and excellent immunologic potency. Radioiodinated hPTH1-34 and (Tyr43)hPTH44-68 produced by hypochlorite iodination techniques can be used to develop sensitive and region-specific PTH assays of use in clinical and research situations.

  12. Preparation of a chemiluminescent imidoester for the non-radioactive labelling of proteins.

    PubMed

    Batmanghelich, S; Brown, R C; Woodhead, J S; Weeks, I; Smith, K

    1992-01-31

    A chemiluminescent aryl acridinium ester was synthesized which possesses an imidate ester group capable of reacting with proteins under mild conditions. The compound can be detected at levels as low as 5.2 x 10(-19) mol using commercially available luminometers and can therefore be used to produce high specific activity labelled antibodies for use in immunochemiluminometric assays. The imidate ester compares favourably with a previously reported N-succinimidyl ester in terms of its labelling properties but is easier to synthesize, requiring one less step. The compound was used to label affinity purified to synthesize, requiring one less step. The compound was used to label affinity purified sheep antibodies to human parathyroid hormone to demonstrate its utility in a two-site immunochemiluminometric assay for the measurement of intact parathyroid hormone. PMID:1619517

  13. Preliminary X-ray diffraction analysis of a thermophilic β-1,3-1,4-glucanase from Clostridium thermocellum.

    PubMed

    Zhang, Lilan; Zhao, Puya; Chen, Chun-Chi; Huang, Chun-Hsiang; Ko, Tzu-Ping; Zheng, Yingying; Guo, Rey-Ting

    2014-07-01

    β-1,3-1,4-Glucanases catalyze the specific hydrolysis of internal β-1,4-glycosidic bonds adjacent to the 3-O-substituted glucose residues in mixed-linked β-glucans. The thermophilic glycoside hydrolase CtGlu16A from Clostridium thermocellum exhibits superior thermal profiles, high specific activity and broad pH adaptability. Here, the catalytic domain of CtGlu16A was expressed in Escherichia coli, purified and crystallized in the trigonal space group P3121, with unit-cell parameters a=b=74.5, c=182.9 Å, by the sitting-drop vapour-diffusion method and diffracted to 1.95 Å resolution. The crystal contains two protein molecules in an asymmetric unit. Further structural determination and refinement are in progress. PMID:25005095

  14. Radioiodinated benzodiazepines: agents for mapping glial tumors

    SciTech Connect

    Van Dort, M.E.; Ciliax, B.J.; Gildersleeve, D.L.; Sherman, P.S.; Rosenspire, K.C.; Young, A.B.; Junck, L.; Wieland, D.M.

    1988-11-01

    Two isomeric iodinated analogues of the peripheral benzodiazepine binding site (PBS) ligand Ro5-4864 have been synthesized and labeled in high specific activity with iodine-125. Competitive binding assays conducted with the unlabeled analogues indicate high affinity for PBS. Tissue biodistribution studies in rats with these /sup 125/I-labeled ligands indicate high uptake of radioactivity in the adrenals, heart, and kidney--tissues known to have high concentrations of PBS. Preadministration of the potent PBS antagonist PK 11195 blocked in vivo uptake in adrenal tissue by over 75%, but to a lesser degree in other normal tissues. In vivo binding autoradiography in brain conducted in C6 glioma bearing rats showed dense, PBS-mediated accumulation of radioactivity in the tumor. Ligand 6 labeled with /sup 123/I may have potential for scintigraphic localization of intracranial glioma.

  15. Simplification of Methods for PET Radiopharmaceutical Syntheses

    SciTech Connect

    Kilbourn, Michael, R.

    2011-12-27

    In an attempt to develop simplified methods for radiochemical synthesis of radiopharmaceuticals useful in Positron Emission Tomography (PET), current commercially available automated synthesis apparati were evaluated for use with solid phase synthesis, thin-film techniques, microwave-accelerated chemistry, and click chemistry approaches. Using combinations of these techniques, it was shown that these automated synthesis systems can be simply and effectively used to support the synthesis of a wide variety of carbon-11 and fluorine-18 labeled compounds, representing all of the major types of compounds synthesized and using all of the common radiochemical precursors available. These techniques are available for use to deliver clinically useful amounts of PET radiopharmaceuticals with chemical and radiochemical purities and high specific activities, suitable for human administration.

  16. In vitro sulfotransferase activity of NodH, a nodulation protein of Rhizobium meliloti required for host-specific nodulation.

    PubMed Central

    Ehrhardt, D W; Atkinson, E M; Faull, K F; Freedberg, D I; Sutherlin, D P; Armstrong, R; Long, S R

    1995-01-01

    Early stages of nodulation involve the exchange of signals between the bacterium and the host plant. Bacterial nodulation (nod) genes are required for Rhizobium spp. to synthesize lipooligosaccharide morphogens, termed Nod factors. The common nod genes encode enzymes that synthesize the factor core structure, which is modified by host-specific gene products. Here we show direct in vitro evidence that Rhizobium meliloti NodH, a host-specific nodulation gene, catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to the terminal 6-O position of Nod factors, and we show substrate requirements for the reaction. Our results indicate that polymerization of the chitooligosaccharide backbone likely precedes sulfation and that sulfation is not absolutely dependent on the presence or the particular structure of the N-acyl modification. NodH sulfation provides a tool for the enzymatic in vitro synthesis of novel Nod factors, or putative Nod factors intermediates, with high specific activity. PMID:7592390

  17. The effect of the [18F]-PEG group on tracer qualification of [4-(phenylamino)-quinazoline-6-YL]-amide moiety--an EGFR putative irreversible inhibitor.

    PubMed

    Dissoki, Samar; Aviv, Yoel; Laky, Desideriu; Abourbeh, Galith; Levitzki, Alexander; Mishani, Eyal

    2007-10-01

    Previous reports have designated the labeled derivatives of [4-(phenylamino)-quinazoline-6-yl]-amide group as the most promising EGFR-PET imaging agent candidates. To further improve tracer qualifications and increase stability and solubility, additional derivatives of this group substituted at the 7-position with various lengths of fluoro-polyethyleneglycol (F-PEG) chains were synthesized. These novel derivatives inhibited EGFR autophosphorylation with IC(50) values of 5-40 nM. The compounds were successfully labeled with fluorine-18 at the PEG chain via a three-step radiosynthesis route. The labeled final products were obtained with a 13-32% decay corrected radiochemical yield, 99% radiochemical purity, and high specific activity. PMID:17574425

  18. Evolving Density and Static Mechanical Properties in Plutonium from Self-Irradiation

    SciTech Connect

    Chung, B W; Thompson, S R; Lema, K E; Hiromoto, D S; Ebbinghaus, B B

    2008-07-31

    Plutonium, because of its self-irradiation by alpha decay, ages by means of lattice damage and helium in-growth. These integrated aging effects result in microstructural and physical property changes. Because these effects would normally require decades to measure, studies are underway to assess the effects of extended aging on the physical properties of plutonium alloys by incorporating roughly 7.5 weight % of highly specific activity isotope {sup 238}Pu into the {sup 239}Pu metal to accelerate the aging process. This paper presents updated results of self-irradiation effects on {sup 238}Pu-enriched alloys measured by immersion density, dilatometry, and tensile tests. After nearly 90 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys continue to decreased in density by {approx}0.002% per year, without void swelling. Quasi-static tensile measurements show that the aging process increases the strength of plutonium alloys.

  19. Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

    SciTech Connect

    Kenneth L. Nash; Sue B. Clark; Gregg Lumetta

    2009-09-23

    With increased application of MOX fuels and longer burnup times for conventional fuels, higher concentrations of the transplutonium actinides Am and Cm (and even heavier species like Bk and Cf) will be produced. The half-lives of the Am isotopes are significantly longer than those of the most important long-lived, high specific activity lanthanides or the most common Cm, Bk and Cf isotopes, thus the greatest concern as regards long-term radiotoxicity. With the removal and transmutation of Am isotopes, radiation levels of high level wastes are reduced to near uranium mineral levels within less than 1000 years as opposed to the time-fram if they remain in the wastes.

  20. Actinide-specific sequestering agents and decontamination applications

    SciTech Connect

    Smith, William L.; Raymond, Kenneth N.

    1981-04-07

    With the commercial development of nuclear reactors, the actinides have become very important industrial elements. A major concern of the nuclear industry is the biological hazard associated with nuclear fuels and their wastes. The acute chemical toxicity of tetravalent actinides, as exemplified by Th(IV), is similar to Cr(III) or Al(III). However, the acute toxicity of 239Pu(IV) is similar to strychnine, which is much more toxic than any of the non-radioactive metals such as mercury. Although the more radioactive isotopes of the transuranium elements are more acutely toxic by weight than plutonium, the acute toxicities of 239Pu, 241Am, and 244Cm are nearly identical in radiation dose, ~100 μCi/kg in rodents. Finally and thus, the extreme acute toxicity of 239Pu is attributed to its high specific activity of alpha emission.

  1. Compatibility of selected elastomers with plutonium glovebox environment

    SciTech Connect

    Burns, R.

    1994-06-01

    This illustrative test was undertaken as a result of on-going failure of elastomer components in plutonium gloveboxes. These failures represent one of the major sources of required maintenance to keep gloveboxes operational. In particular, it was observed that the introduction of high specific activity Pu-238 into a glovebox, otherwise contaminated with Pu-239, resulted in an inordinate failure of elastomer components. Desiring to keep replacement of elastomer components to a minimum, a decision to explore a few possible alternative elastomer candidates was undertaken and reported upon herewith. Sample specimens of Neoprene, Urethane, Viton, and Hypalon elastomeric formulations were obtained from the Bacter Rubber Company. Strips of the elastomer specimens were placed in a plutonium glovebox and outside of a glovebox, and were observed for a period of three years. Of the four types of elastomers, only Hypalon remained completely viable.

  2. Radiochemical Separations:. Useful Methods for the Preparation of No-Carrier Solutions of Different Radionuclides for Metabolic Radiotherapy

    NASA Astrophysics Data System (ADS)

    Zona, C.; Groppi, F.; Persico, E.; Canella, L.; Bonardi, M. L.; Chinol, M.; Abbas, K.; Holzwarth, U.; Gibson, N.

    2008-06-01

    In Nuclear Medicine, radionuclides are used in the detection and the treatment for cancers and others diseases. We must obtain, for therapeutic purposes, solutions of radionuclides in the required chemical form, with an high specific activity (AS). To reach our goal we must, first, obtain no-carrier-added (NCA) solutions. In this work we present different methods for the production of NCA radionuclides, based on either wet-chemistry, or thermc- and radio-chromatography. We set up four different methods: two for the preparation of the alpha emitter 211At, and two for the beta emitters 186gRe and 90Y. These radionuclides had been chosen because of their chemical and nuclear properties as their half-life, type, abundance and energy of emissions, that make them among the most promising radionuclides to label compounds for the metabolic radionuclide therapy.

  3. Novel strategies for ultrahigh specific activity targeted nanoparticles

    SciTech Connect

    Zhou, Dong

    2012-12-13

    We have developed novel strategies optimized for preparing high specific activity radiolabeled nanoparticles, targeting nuclear imaging of low abundance biomarkers. Several compounds have been labeled with F-18 and Cu-64 for radiolabeling of SCK-nanoparticles via Copper(I) catalyzed or copper-free alkyne-azide cyclolization. Novel strategies have been developed to achieve ultrahigh specific activity with administrable amount of dose for human study using copper-free chemistry. Ligands for carbonic anhydrase 12 (CA12), a low abundance extracellular biomarker for the responsiveness of breast cancer to endocrine therapie, have been labeled with F-18 and Cu-64, and one of them has been evaluated in animal models. The results of this project will lead to major improvements in the use of nanoparticles in nuclear imaging and will significantly advance their potential for detecting low abundance biomarkers of medical importance.

  4. Commercial disposal of High Integrity Containers (HICs) containing EPICOR-II prefilters from Three Mile Island

    SciTech Connect

    McConnell, Jr, J W; Lynch, R J; Tyacke, M J

    1985-09-01

    This report describes the processes of loading, transporting, and commercially disposing of 45 High Integrity Containers (HICs), each containing an EPICOR-II prefilter. Also described are the improvements that were applied in the disposition of the 45 commercial EPICOR-II prefilters at the Idaho National Engineering Laboratory (INEL), versus those used for the demonstration unit. The significance of this effort was that the commercial disposal campaign involved the first-of-a-kind production use of a reinforced concrete HIC at the US Ecology, Inc. facility in the State of Washington. This allowed for safe disposal of high-specific-activity ion exchange material in EPICOR-II prefilters generated during the cleanup of the Unit-2 Auxiliary and Fuel Handling Building of the Three Mile Island Nuclear Power Station. 26 figs.

  5. New microbial growth factor

    NASA Technical Reports Server (NTRS)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  6. A method to identify and characterize Z-DNA binding proteins using a linear oligodeoxynucleotide

    NASA Technical Reports Server (NTRS)

    Herbert, A. G.; Rich, A.

    1993-01-01

    An oligodeoxynucleotide that readily flips to the Z-DNA conformation in 10mM MgCl2 was produced by using Klenow enzyme to incorporate 5-bromodeoxycytosine and deoxyguanosine into a (dC-dG)22 template. During synthesis the oligomer can be labeled with 32P to high specific activity. The labeled oligodeoxynucleotide can be used in bandshift experiment to detect proteins that bind Z-DNA. This allows the binding specificity of such proteins to be determined with high reliability using unlabeled linear and supercoiled DNA competitors. In addition, because the radioactive oligodeoxynucleotide contains bromine atoms, DNA-protein complexes can be readily crosslinked using UV light. This allows an estimate to be made of the molecular weight of the proteins that bind to the radioactive probe. Both techniques are demonstrated using a goat polyclonal anti-Z-DNA antiserum.

  7. [(14) C]-AZD1152 drug substance manufacture: challenges of an IV-infusion dosed human mass balance study in patients.

    PubMed

    Bushby, Nick; Bergin, Julie; Harding, John

    2016-05-30

    [(14) C]-AZD1152 (barasertib) drug substance was prepared in order to support a hADME study that was to be dosed as an intravenous infusion to patients with acute myeloid leukaemia. A long patient recruitment time (1-2 years) was expected, and because of its limited stability several batches of [(14) C]-AZD1152 drug substance needed to be prepared in order to maintain a supply of [(14) C]-AZD1152 in the clinic over this period. A method was developed to purify the [(14) C]-AZD1152 to a GMP-like standard at high specific activity to provide material for each of these batches. This approach to the delivery of the drug substance was successful in supplying the study with radiolabelled drug for over 1 year until all patients had been recruited. PMID:27169761

  8. Hot atom chemistry and radiopharmaceuticals

    SciTech Connect

    Krohn, Kenneth A.; Moerlein, Stephen M.; Link, Jeanne M.; Welch, Michael J.

    2012-12-19

    The chemical products made in a cyclotron target are a combined result of the chemical effects of the nuclear transformation that made the radioactive atom and the bulk radiolysis in the target. This review uses some well-known examples to understand how hot atom chemistry explains the primary products from a nuclear reaction and then how radiation chemistry is exploited to set up the optimal product for radiosynthesis. It also addresses the chemical effects of nuclear decay. There are important principles that are common to hot atom chemistry and radiopharmaceutical chemistry. Both emphasize short-lived radionuclides and manipulation of high specific activity nuclides. Furthermore, they both rely on radiochromatographic separation for identification of no-carrieradded products.

  9. Recovery and purification of nickel-63 from HFIR-irradiated targets

    SciTech Connect

    Williams, D.F.; O`Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.

    1993-06-01

    The production of large quantities of high-specific-activity {sup 63}Ni (>10 Ci/g) requires both a highly enriched {sup 62}Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at {sup 51}Cr, and scandium, present as {sup 46}Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.

  10. Synthesis of (3) H, (2) H4 and (14) C-SCH 417690 (Vicriviroc).

    PubMed

    Hesk, D; Borges, S; Hendershot, S; Koharski, D; McNamara, P; Ren, S; Saluja, S; Truong, V; Voronin, K

    2016-05-15

    Vicriviroc or SCH 417690 is a potent and selective antagonist of the CCR5 receptor. CCR5 receptor antagonists have the potential for the treatment of HIV infections. Four distinct isotopically labelled forms of SCH 417690 were synthesized. Low specific activity [(3) H]SCH 417690 was prepared for a preliminary absorption, distribution, metabolism and excretion evaluation of the compound and [(14) C]SCH 417690 for more definitive absorption, distribution, metabolism and excretion work, including an absorption, metabolism and excretion study in man. In addition, high specific activity [(3) H]SCH 417690 was prepared for CCR5 receptor binding work and [(2) H4 ]SCH 417690 was prepared as an internal standard for a liquid chromatography-mass spectrometry bioanalytical method. The paper discusses the synthesis of four isotopically labelled forms of SCH 417690. PMID:26991320

  11. Estrogen binding, receptor mRNA, and biologic response in osteoblast-like osteosarcoma cells

    SciTech Connect

    Komm, B.S.; Terpening, C.M.; Benz, D.J.; Graeme, K.A.; Gallegos, A.; Korc, M.; Greene, G.L.; O'Malley, B.W.; Haussler, M.R.

    1988-07-01

    High specific activity estradiol labeled with iodine-125 was used to detect approximately 200 saturable, high-affinity (dissociation constant approximately equal to 1.0 nM) nuclear binding sites in rat (ROS 17/2.8) and human (HOS TE85) clonal osteoblast-like osteosarcoma cells. Of the steroids tested, only testosterone exhibited significant cross-reactivity with estrogen binding. RNA blot analysis with a complementary DNA probe to the human estrogen receptor revealed putative receptor transcripts of 6 to 6.2 kilobases in both rat and human osteosarcoma cells. Type I procollagen and transforming growth factor-beta messenger RNA levels were enhanced in cultured human osteoblast-like cells treated with 1 nM estradiol. Thus, estrogen can act directly on osteoblasts by a receptor-mediated mechanism and thereby modulate the extracellular matrix and other proteins involved in the maintenance of skeletal mineralization and remodeling.

  12. Mechanism of Electrophilic Fluorination with Pd(IV): Fluoride Capture and Subsequent Oxidative Fluoride Transfer(.)

    PubMed

    Brandt, Jochen R; Lee, Eunsung; Boursalian, Gregory B; Ritter, Tobias

    2014-01-01

    Electrophilic fluorinating reagents derived from fluoride are desirable for the synthesis of (18)F-labeled molecules for positron emission tomography (PET). Here, we study the mechanism by which a Pd(IV)-complex captures fluoride and subsequently transfers it to nucleophiles. The intermediate Pd(IV)-F is formed with high rates even at the nano- to micromolar fluoride concentrations typical for radiosyntheses with (18)F due to fast formation of an outer-sphere complex between fluoride and Pd(IV). The subsequent fluorine transfer from the Pd(IV)-F complex is proposed to proceed through an unusual SET/fluoride transfer/SET mechanism. The findings detailed in this manuscript provide a theoretical foundation suitable for addressing a more general approach for electrophilic fluorination with high specific activity (18)F PET imaging. PMID:24376910

  13. A modified, high yield procedure for the synthesis of unlabeled and 14C-labeled 4-methylene-DL-glutamic acid.

    PubMed

    Powell, G K; Dekker, E E

    1981-01-01

    This paper describes the complete chemical synthesis of 4-methylene-DL-glutamic acid from diethylmalonate, formaldehyde and diethyl acetamidomalonate. The amino acid was obtained pure following ion-exchange chromatography and/or crystallization from hot water in an overall yield of 30% based on the amount of diethylmalonate used. Several physico-chemical characteristics of the synthetic compound were determined, including ir and pmr spectra, chromatography on paper, retention time on an amino acid analyzer, pK values and melting point; all properties of the synthetic material were found to be identical to those seen with the naturally occurring L-isomer. The procedure for obtaining gram quantities of the unlabeled compound has also been modified for the synthesis of high specific activity (10.6 mCi/mol) 4-methylene-[2-14C]-DL-glutamic acid. PMID:6265898

  14. Bioactive proteins from stonefish venom.

    PubMed

    Khoo, Hoon Eng

    2002-09-01

    1. Of all the venomous fish known, the stonefish is one of the most commonly encountered by man. Studies on its venom started in the 1950s, but little work was performed after that until several groups revived interest in the venom in the 1980s after easier accessibility to the fish. 2. Stonefish venom is a mixture of proteins, containing several enzymes, including hyaluronidase of high specific activity. A purified stonefish hyaluronidase has been characterized. 3. Several of the effects of the crude venom have been isolated to a protein lethal factor that has cytolytic, neurotoxic and hypotensive activity. This protein is stonustoxin from Synanceja horrida, trachynilysin from Synanceja trachynis and verrucotoxin from Synanceja verrucosa. 4. The biochemical properties and activities of these protein lethal factors are reviewed. PMID:12165046

  15. Fluorine-18 Radiochemistry, Labeling Strategies and Synthetic Routes

    PubMed Central

    2015-01-01

    Fluorine-18 is the most frequently used radioisotope in positron emission tomography (PET) radiopharmaceuticals in both clinical and preclinical research. Its physical and nuclear characteristics (97% β+ decay, 109.7 min half-life, 635 keV positron energy), along with high specific activity and ease of large scale production, make it an attractive nuclide for radiochemical labeling and molecular imaging. Versatile chemistry including nucleophilic and electrophilic substitutions allows direct or indirect introduction of 18F into molecules of interest. The significant increase in 18F radiotracers for PET imaging accentuates the need for simple and efficient 18F-labeling procedures. In this review, we will describe the current radiosynthesis routes and strategies for 18F labeling of small molecules and biomolecules. PMID:25473848

  16. Nucleophilic fluorination of aromatic compounds

    DOEpatents

    Satyamurthy, Nagichettiar; Barrio, Jorge R

    2014-03-18

    Iodylbenzene derivatives substituted with electron donating as well as electron withdrawing groups on the aromatic ring are used as precursors in aromatic nucleophilic substitution reactions. The iodyl group (IO.sub.2) is regiospecifically substituted by nucleophilic fluoride to provide the corresponding fluoroaryl derivatives. No-carrier-added [F-18]fluoride ion derived from anhydrous [F-18](F/Kryptofix, [F-18]CsF or a quaternary ammonium fluoride (e.g., Me.sub.4NF, Et.sub.4NF, n-Bu.sub.4NF, (PhCH.sub.2).sub.4NF) exclusively substitutes the iodyl moiety in these derivatives and provides high specific activity F-18 labeled fluoroaryl analogs. Iodyl derivatives of a benzothiazole analog and 6-iodyl-L-dopa derivatives have been synthesized as precursors and have been used in the preparation of no-carrier-added [F-18]fluorobenzothiazole as well as 6-[F-18]fluoro-L-dopa.

  17. Purification and characterization of naturally occurring HIV-1 (South African subtype C) protease mutants from inclusion bodies.

    PubMed

    Maseko, Sibusiso B; Natarajan, Satheesh; Sharma, Vikas; Bhattacharyya, Neelakshi; Govender, Thavendran; Sayed, Yasien; Maguire, Glenn E M; Lin, Johnson; Kruger, Hendrik G

    2016-06-01

    Human immunodeficiency virus (HIV) infections in sub-Saharan Africa represent about 56% of global infections. Many studies have targeted HIV-1 protease for the development of drugs against AIDS. Recombinant HIV-1 protease is used to screen new drugs from synthetic compounds or natural substances. Along with the wild type (C-SA) we also over-expressed and characterized two mutant forms from patients that had shown resistance to protease inhibitors. Using recombinant DNA technology, we constructed three recombinant plasmids in pGEX-6P-1 and expressed them containing a sequence encoding wild type HIV protease and two mutants (I36T↑T contains 100 amino acids and L38L↑N↑L contains 101 amino acids). These recombinant proteins were isolated from inclusion bodies by using QFF anion exchange and GST trap columns. In SDS-PAGE, we obtained these HIV proteases as single bands of approximately 11.5, 11.6 and 11.7 kDa for the wild type, I36T↑Tand L38L↑N↑L mutants, respectively. The enzyme was recovered efficiently (0.25 mg protein/L of Escherichia coli culture) and had high specific activity of 2.02, 2.20 and 1.33 μmol min(-1) mg(-1) at an optimal pH of 5 and temperature of 37 °C for the wild type, I36T↑T and L38L↑N↑L, respectively. The method employed here provides an easy and rapid purification of the HIV-1(C-SA) protease from the inclusion bodies, with high yield and high specific activities. PMID:26917227

  18. Production of Multimeric Prostate-Specific Membrane Antigen Small Molecule Radiotracers using a Solid-Phase 99mTc Pre-Loading Strategy

    PubMed Central

    Misra, Preeti; Humblet, Valerie; Pannier, Nadine; Maison, Wolfgang; Frangioni, John V.

    2008-01-01

    Small molecule ligands specific for prostate-specific membrane antigen (PSMA) have the potential to improve prostate cancer imaging. However, highly charged ligands are difficult to label with 99mTc and to purify. In this study, we present an adamantane-trimerized small molecule that has nanomolar binding to PSMA, but that also has 12 negative charges. Methods To convert this molecule into a clinically viable SPECT diagnostic, we have developed a simple, cartridge-based, solid-phase pre-labeling strategy that, within 25 minutes, converts readily available and inexpensive 99mTc-pertechnetate into a chemically pure complex, with a reactive N-hydroxysuccinimide (NHS) ester, in neat organic solvent. This stable intermediate can label any amine-containing small molecule or peptide with 99mTc in one step, with high specific activity, and without the need for HPLC. Results Solid-phase conversion of 99mTc-pertechnetate to 99mTc-MAS3-NHS could be completed in 25 minutes, with >99% radiochemical purity and with no co-ligands present. This intermediate was then conjugated to adamantane-trimerized GPI in one step with >95% yield, and no need for HPLC purification. The final molecule bound specifically to living human tumor cells expressing PSMA on their surface. Quantitative comparison was made among GPI monomer, GPI trimer, and their 99mTc derivatives. Conclusion Our study describes a simple cartridge-based conversion of 99mTc pertechnetate to a useful, pre-loaded NHS ester intermediate that takes only 25 minutes to prepare and results in >99% radiochemical purity. Using this chemistry, we produce a high specific activity, 99mTc-labeled, PSMA-targeted small molecule, and demonstrate gamma ray radioscintigraphic imaging of living human prostate cancer cells. PMID:17631555

  19. Synthesis of radiolabeled chiral probes for binding and receptor studies: Radiolabeled juvenoids and inositol phosphates

    SciTech Connect

    Boehm, M.F.

    1988-01-01

    This study is composed of two parts. Part I describes the synthesis of seven high specific activity radioligands for the characterization of macromolecular receptors for juvenile hormone analog-type labeled insect growth regulators. These radioligands include (1) ({sup 125}I)-radioiodinated iodovinyl methoprenol and iodovinyl methoprene (2000 Ci/mmol), (2) ({sup 3}H)-labeled (7S)-methoprene and (7S)-hydroprene (>60 Ci/mmol), potent dodecadienoate insect growth regulators, (3) ({sup 3}H)-labeled fenoxycarb (Maag) and S-31183 Sumitomo, phenoxyphenyl ether IGRs, and (4) ({sup 3}H)-methoprene diazoketone, a photoaffinity label for characterizing receptor sites. The attempted synthesis of high specific activity tritium labeled JH III is also described. Biological studies utilizing these radioligands show separate nuclear receptor proteins for JH homologs and juvenoids. Part II describes the preparation of enantiomerically enriched radiolabeled myo-inositol-1,3,4-trisphosphate (myo-Ins(1,3,4)P{sub 3}) and fluorinated analogs of myo-Ins(1,3,4)P{sub 3} for examining receptors for myo-Ins(1,3,4)P{sub 3}. Three compounds have been synthesized. These include 2-fluoro- and 2,2-difluoro-2-deoxy analogs of DL-myo-Ins(1,3,4)P{sub 3}, D- and L-myo-Ins(1,3,4)P{sub 3} at >95% enantiomeric excess and, D-and L-({sup 3}H)-myo-Ins(1,3,4)P{sub 3} enantiomers with specific activities of 15 Ci/mmol.

  20. Use of Tc-99m-galactosyl-neoglycoalbumin (Tc-NGA) to determine hepatic blood flow

    SciTech Connect

    Stadalnik, R.C.; Vera, D.R.; Woodle, E.S.; Hutak, D.P.; Ward, R.E.; Krohn, K.A.

    1984-01-01

    Tc-NGA is a new liver radiopharmaceutical which binds to a hepatocyte-specific membrane receptor. Three characteristics of Tc-NGA can be exploited in the measurement of hepatic blood flow (HBF): 1) ability to alter the affinity of Tc-NGA for its receptor by changing the galactose: albumin ratio; 2) ability to achieve a high specific activity with Tc-99m labeling; and 3) ability to administer a high molar dose of Tc-NGA without physiologic side effects. In addition, kinetic modeling of Tc-NGA dynamic data can provide estimates of hepatic receptor concentration. In experimental studies in young pigs, HBF was determined using two techniques: 1) kinetic modeling of dynamic data using moderate affinity, low specific activity Tc-NGA (Group A, n=12); and 2) clearance (CL) technique using high affinity, high specific activity Tc-NGA (Group B, n=4). In both groups, HBF was determined simultaneously by continuous infusion of indocyanine green (CI-ICG) with hepatic vein sampling. Regression analysis of HBF measurements obtained with the Tc-NGA kinetic modeling technique and the CI-ICG technique (Group A) revealed good correlation between the two techniques (r=0.802, p=0.02). Similarly, HBF determination by the clearance technique (Group B) provided highly accurate measurements when compared to the CI-ICG technique. Hepatic blood flow measurements by the clearance technique (CL-NGA) fell within one standard deviation of the error associated with each CI-ICG HBF measurement (all CI-ICG standard deviations were less than 10%).

  1. Unexpectedly high radioactivity burdens in ice-rafted sediments from the Canadian Arctic Archipelago.

    PubMed

    Cota, Glenn F; Cooper, Lee W; Darby, Dennis A; Larsen, I L

    2006-07-31

    Unexpectedly high specific activities of (137)Cs (1800-2000 Bq kg(-1) dry weight) have been detected in fine-grained sediments entrained in multi-year sea ice floes grounded in Resolute Bay near the center of the Northwest Passage through the Canadian Arctic Archipelago. These results are remarkable because: (1) the specific activities are about two orders of magnitude higher than average specific activities detected in previous studies of sea ice rafted sediments from the Arctic Ocean, (2) two independent observations of these unexpectedly high specific activities were made several years apart, (3) the sampling site is on the opposite side of the Arctic basin from potential radioactive sources such as disposal and weapons testing sites of the former Soviet Union and nuclear fuel reprocessing sites in western Europe, and (4) the closest compositional match to known geologic source regions is Banks Island, on the western edge of the Arctic Archipelago, although a smaller number of grains from one of the two samples were mineralogically matched to sediments in the Laptev Sea. Consequently, the sediments are probably not from a single distinct source and were likely mixed during sea ice transport. Coupled with previous observations of higher radionuclide specific activities in some sea ice rafted sediments relative to bottom sediments, these new observations indicate that comparatively high as well as variable radioactive contaminant burdens in ice rafted sediments must be common and geographically independent of proximity to known contaminant sources. The mechanisms that would facilitate these unexpected high radionuclide burdens in sea ice are not known and require additional study, as well as investigations of the implications for the transport and fate of contaminants in Arctic sea ice. PMID:16197983

  2. Erythrocyte glucose-6-phosphate dehydrogenase from Brazilian opossum Didelphis marsupialis.

    PubMed

    Barretto, O C de O; Oshiro, M; Oliveira, R A G; Fedullo, J D L; Nonoyama, K

    2006-05-01

    In a comparative study of erythrocyte metabolism of vertebrates, the specific activity of glucose-6-phosphate dehydrogenase (G6PD) of the Brazilian opossum Didelphis marsupialis in a hemolysate was shown to be high, 207 +/- 38 IU g-1 Hb-1 min-1 at 37 degrees C, compared to the human erythrocyte activity of 12 +/- 2 IU g-1 Hb-1 min-1 at 37 degrees C. The apparent high specific activity of the mixture led us to investigate the physicochemical properties of the opossum enzyme. We report that reduced glutathione (GSH) in the erythrocytes was only 50% higher than in human erythrocytes, a value lower than expected from the high G6PD activity since GSH is maintained in a reduced state by G6PD activity. The molecular mass, determined by G-200 Sephadex column chromatography at pH 8.0, was 265 kDa, which is essentially the same as that of human G6PD (260 kDa). The Michaelis-Menten constants (Km: 55 microM) for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (Km: 3.3 microM) were similar to those of the human enzyme (Km: 50-70 and Km: 2.9-4.4, respectively). A 450-fold purification of the opossum enzyme was achieved and the specific activity of the purified enzyme, 90 IU/mg protein, was actually lower than the 150 IU/mg protein observed for human G6PD. We conclude that G6PD after purification from the hemolysate of D. marsupialis does not have a high specific activity. Thus, it is quite probable that the red cell hyperactivity reported may be explained by increased synthesis of G6PD molecules per unit of hemoglobin or to reduced inactivation in the RBC hemolysate. PMID:16648898

  3. Synthesis and characterization of a high affinity radioiodinated probe for the alpha 2-adrenergic receptor

    SciTech Connect

    Lanier, S.M.; Hess, H.J.; Grodski, A.; Graham, R.M.; Homcy, C.J.

    1986-03-01

    The availability of radioiodinated probes has facilitated the localization and molecular characterization of cell membrane receptors for hormones and neurotransmitters. However, such probes are not available for the study of the alpha 2-adrenergic receptor. This report describes the synthesis and characterization of functionalized derivatives of the selective alpha 2-adrenergic antagonists, rauwolscine and yohimbine, which can be radiolabeled to high specific activity with 125I. Following demethylation of rauwolscine or yohimbine, the resultant carboxylic acid derivatives were reacted with 4-aminophenethylamine to yield the respective 4-aminophenethyl carboxamides, 17 alpha-hydroxy-20 alpha-yohimban-16 beta-(N-4-amino-phenethyl)carboxamide (rau-pAPC) and 17 alpha-hydroxy-20 beta-yohimban-16 alpha-(N-4-aminophenethyl)carboxamide. In competitive inhibition studies using rat renal membranes and the radioligand (3H)rauwolscine, rau-pAPC (Ki = 11 +/- 1 nM) exhibited a 14-fold greater affinity than the corresponding yohimbine derivative (Ki = 136 +/- 45 nM). The higher affinity compound, rau-pAPC, was radioiodinated by the chloramine T method, and the product, 125I-rau-pAPC (17 alpha-hydroxy-20 alpha-yohimban-16 beta-(N-4-amino-3 -(125I)iodophenethyl)carboxamide), was purified by reverse phase HPLC to high specific activity (2175 Ci/mmol) and its binding characteristics were investigated in rat kidney membranes. Specific binding of 125I-rau-pAPC was saturable and of high affinity as determined by Scatchard analysis (KD = 1.8 +/- 0.3 nM) or from kinetic studies (KD = k2/k1 = 0.056 +/- 0.013 min-1)/4.3 +/- 0.2 X 10(7) M-1 min-1 = 1.3 +/- 0.3 nM).

  4. Exploitation of nano alumina for the chromatographic separation of clinical grade 188Re from 188W: a renaissance of the 188W/188Re generator technology.

    PubMed

    Chakravarty, Rubel; Shukla, Rakesh; Ram, Ramu; Venkatesh, Meera; Tyagi, Avesh Kumar; Dash, Ashutosh

    2011-08-15

    The (188)W/(188)Re generator using an acidic alumina column for chromatographic separation of (188)Re has remained the most popular procedure world over. The capacity of bulk alumina for taking up tungstate ions is limited (∼50 mg W/g) necessitating the use of very high specific activity (188)W (185-370 GBq/g), which can be produced only in very few high flux reactors available in the world. In this context, the use of high-capacity sorbents would not only mitigate the requirement of high specific activity (188)W but also facilitate easy access to (188)Re. A solid state mechanochemical approach to synthesize nanocrystalline γ-Al(2)O(3) possessing very high W-sorption capacity (500 mg W/g) was developed. The structural and other investigations of the material were carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer Emmett Teller (BET) surface area analysis, thermogravimetric-differential thermal analysis (TG-DTA), and dynamic light scattering (DLS) techniques. The synthesized material had an average crystallite size of ∼5 nm and surface area of 252 ± 10 m(2)/g. Sorption characteristics such as distribution ratios (K(d)), capacity, breakthrough profile, and elution behavior were investigated to ensure quantitative uptake of (188)W and selective elution of (188)Re. A 11.1 GBq (300 mCi) (188)W/(188)Re generator was developed using nanocrystalline γ-Al(2)O(3), and its performance was evaluated for a period of 6 months. The overall yield of (188)Re was >80%, with >99.999% radionuclidic purity and >99% radiochemical purity. The eluted (188)Re possessed appreciably high radioactive concentration and was compatible for the preparation of (188)Re labeled radiopharmaceuticals. PMID:21726091

  5. New lyophilized kit for rapid radiofluorination of peptides.

    PubMed

    McBride, William J; D'Souza, Christopher A; Karacay, Habibe; Sharkey, Robert M; Goldenberg, David M

    2012-03-21

    Radiolabeling compounds with positron-emitting radionuclides often involves a time-consuming, customized process. Herein, we report a simple lyophilized kit formulation for labeling peptides with (18)F, based on the aluminum-fluoride procedure. The prototype kit contains IMP485, a NODA (1,4,7-triazacyclononane-1,4-diacetate)-MPAA (methyl phenylacetic acid)-di-HSG (histamine-succinyl-glycine) hapten-peptide, [NODA-MPAA-D-Lys(HSG)-D-Tyr-D-Lys(HSG)-NH(2)], used for pretargeting, but we also examined a similar kit formulation for a somatostatin-binding peptide [IMP466, NOTA-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Throl] bearing a NOTA ligand to determine if the benefits of using a kit can be extended to other AlF-binding peptides. The NODA-MPAA ligand forms a single stable complex with (AlF)(2+) in high yields. In order to establish suitable conditions for a facile kit, the formulation was optimized for pH, peptide to Al(3+) ratio, bulking agent, radioprotectant, and the buffer. For optimal labeling, the kit was reconstituted with an aqueous solution of (18)F(-) and ethanol (1:1), heated at 100-110 °C for 15 min, and then simply and rapidly purified using one of two equally effective solid-phase extraction (SPE) methods. Al(18)F-IMP485 was isolated as a single isomer complex, in high yield (45-97%) and high specific activity (up to 223 GBq/μmol), within 20 min. The labeled product was stable in human serum at 37 °C for 4 h and in vivo, urine samples showed the intact product was eliminated. Tumor targeting of the Al(18)F-IMP485 in nude mice bearing human colon cancer xenografts pretargeted with an anti-CEACAM5 bispecific antibody showed very low uptake (0.06% ± 0.02 ID/g) in bone, further illustrating its stability. At 1 h, pretargeted animals had high Al(18)F-IMP485 tumor uptake (28.1% ± 4.5 ID/g), with ratios of 9 ± 4, 123 ± 38, 110 ± 43, and 120 ± 108 for kidney, liver, blood and bone, respectively. Tumor uptake remained high at 3 h postinjection, with increased

  6. A New Lyophilized Kit for Rapid Radiofluorination of Peptides

    PubMed Central

    McBride, William J.; D'Souza, Christopher A.; Karacay, Habibe; Sharkey, Robert M.; Goldenberg, David M.

    2012-01-01

    Radiolabeling compounds with positron-emitting radionuclides often involves a time-consuming, customized process. Herein, we report a simple lyophilized kit formulation for labeling peptides with 18F, based on the aluminum-fluoride procedure. The prototype kit contains IMP485, a NODA (1,4,7-triazacyclononane-1,4-diacetate)-MPAA (methyl phenylacetic acid)-di-HSG (histamine-succinyl-glycine) hapten-peptide, [NODA-MPAA-D-Lys(HSG)-D-Tyr-D-Lys(HSG)-NH2], used for pretargeting, but we also examined a similar kit formulation for a somatostatin-binding peptide [IMP466, NOTA-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Throl] bearing a NOTA ligand to determine if the benefits of using a kit can be extended to other AlF-binding peptides. The NODA-MPAA ligand forms a single stable complex with (AlF)2+ in high yields. In order to establish suitable conditions for a facile kit, the formulation was optimized for pH, peptide to Al3+ ratio, bulking agent, radioprotectant, and the buffer. For optimal labeling, the kit was reconstituted with an aqueous solution of 18F− and ethanol (1:1), heated at 100–110 °C for 15 min, and then simply and rapidly purified using one of two equally effective solid-phase extraction (SPE) methods. Al18F-IMP485 was isolated as a single isomer complex, in high yield (45–97%) and high specific activity (up to 223 GBq/μmol), within 20 min. The labeled product was stable in human serum at 37 °C for 4 h and in vivo, urine samples showed the intact product was eliminated. Tumor targeting of the Al18F-IMP485 in nude mice bearing human colon cancer xenografts pretargeted with an anti-CEACAM5 bispecific antibody showed very low uptake (0.06% ± 0.02 ID/g) in bone, further illustrating its stability. At 1 h, pretargeted animals had high Al18F-IMP485 tumor uptake (28.1% ± 4.5 ID/g), with ratios of 9 ± 4, 123 ± 38, 110 ± 43 and 120 ± 108 for kidney, liver, blood and bone, respectively. Tumor uptake remained high at 3 h post-injection, with increased tumor

  7. Expedited Synthesis of Fluorine-18 Labeled Phenols. A Missing Link in PET Radiochemistry

    SciTech Connect

    Katzenellenbogen, John A.; Zhou, Dong

    2015-03-26

    Fluorine-18 (F-18) is arguably the most valuable radionuclide for positron emission tomographic (PET) imaging. However, while there are many methods for labeling small molecules with F-18 at aliphatic positions and on electron-deficient aromatic rings, there are essentially no reliable and practical methods to label electron-rich aromatic rings such as phenols, with F-18 at high specific activity. This is disappointing because fluorine-labeled phenols are found in many drugs; there are also many interesting plant metabolites and hormones that contain either phenols or other electron-rich aromatic systems such as indoles whose metabolism, transport, and distribution would be interesting to study if they could readily be labeled with F-18. Most approaches to label phenols with F-18 involve the labeling of electron-poor precursor arenes by nucleophilic aromatic substitution, followed by subsequent conversion to phenols by oxidation or other multi-step sequences that are often inefficient and time consuming. Thus, the lack of good methods for labeling phenols and other electron-rich aromatics with F-18 at high specific activity represents a significant methodological gap in F-18 radiochemistry that can be considered a “Missing Link in PET Radiochemistry”. The objective of this research project was to develop and optimize a series of unusual synthetic transformations that will enable phenols (and other electron-rich aromatic systems) to be labeled with F-18 at high specific activity, rapidly, reliably, and conveniently, thereby bridging this gap. Through the studies conducted with support of this project, we have substantially advanced synthetic methodology for the preparation of fluorophenols. Our progress is presented in detail in the sections below, and much has been published or presented publication; other components are being prepared for publication. In essence, we have developed a completely new method to prepare o-fluorophenols from non-aromatic precursors

  8. Non-carrier-added 186, 188Re labeled 17a-ethynylestradiol : a potential breast cancer imaging and therapy agent

    SciTech Connect

    Fassbender, M. E.; Phillips, Dennis R.; Peterson, E. J.; Ott, K. C.; Arterburn, J. B.

    2001-01-01

    Receptor-targeted radiopharmaceuticals constitute potential agents for the diagnosis and therapy of cancer. Breast cancer is the most prevalent form of diagnosed cancer in women in the United States, and it accounts for the second highest number of cases of cancer fatalities (1). In Approximately two-thirds of the breast tumors, estrogen and progesterone steroid hormone receptors can be found. Such tumors can often be treated successfully with anti-estrogen hormone therapy (2). Hence, the ability to determine the estrogen receptor (ER) contend of the breast tumor is essential for making the most appropriate choice of treatment for the patient. Along with this diagnostic aspect, steroid-based radiopharmaceuticals with high specific activity offer an encouraging prospect for therapeutic applications: {sup 186,188}Re labeled steroids binding to receptors expressed by cancer cells appear to be potential agents for the irradiation of small to medium-sized tumors. {sup 186}Re has been regarded as an ideal radionuclide for radiotherapy due to its appropriate half-live of 90 h and {beta}-energy of 1.07 MeV. Moreover, the {gamma}-emission of 137 keV that allows in vivo imaging while in therapy is an additional bonus. {sup 188}Re is obtained from a {sup 188}W/{sup 188}Re radionuclide generator system, representing an advantage for availability at radiopharmacy laboratory by daily elution. In addition, {sup 188}Re emits high energy beta particles with an average energy of 769 keV, and the emission of the 155 keV allows simultaneous imaging for biodistribution evaluation in vivo. In order to avoid competitive saturation of the binding sites of the ligand receptor, Re labeled steroids with high specific activity are required, and the removal of all excess unlabeled ligands is mandatory. {sup 188}Re is eluted from a {sup 188}W/{sup 188}Re generator produced and provided by Oak Ridge National Laboratory (3). This paper outlines the solid phase-supported preparation of an n

  9. Production, characterization, cloning and sequence analysis of a monofunctional catalase from Serratia marcescens SYBC08.

    PubMed

    Zeng, Hua-Wei; Cai, Yu-Jie; Liao, Xiang-Ru; Zhang, Feng; Zhang, Da-Bing

    2011-04-01

    A monofunctional catalase from Serratia marcescens SYBC08 produced by liquid state fermentation in 7 liter fermenter was isolated and purified by ammonium sulfate precipitation (ASP), ion exchange chromatography (IEC), and gel filtration (GF) and characterized. Its sequence was analyzed by LC-MS/MS technique and gene cloning. The highest catalase production (20,289 U · ml(-1)) was achieved after incubation for 40 h. The purified catalase had an estimated molecular mass of 230 kDa, consisting of four identical subunits of 58 kDa. High specific activity of the catalase (199,584 U · mg(-1) protein) was 3.44 times higher than that of Halomonas sp. Sk1 catalase (57,900 U · mg(-1) protein). The enzyme without peroxidase activity was found to be an atypical electronic spectrum of monofunctional catalase. The apparent K(m) and V(max) were 78 mM and 188, 212 per µM H(2) O(2) µM heme(-1) s(-1), respectivly. The enzyme displayed a broad pH activity range (pH 5.0-11.0), with optimal pH range of 7.0-9.0: It was most active at 20 °C and had 78% activity at 0 °C. Its thermo stability was slightly higher compared to that of commercial catalase from bovine liver. LC-MS/MS analysis confirmed that the deduced amino acid sequence of cloning gene was the catalase sequence from Serratia marcescens SYBC08. The sequence was compared with that of 23 related catalases. Although most of active site residues, NADPH-binding residues, proximal residues of the heme, distal residues of the heme and residues interacting with a water molecule in the enzyme were well conserved in 23 related catalases, weakly conserved residues were found. Its sequence was closely related with that of catalases from pathogenic bacterium in the family Enterobacteriaceae. This result imply that the enzyme with high specific activity plays a significant role in preventing those microorganisms of the family Enterobacteriaceae against hydrogen peroxide resulted in cellular damage. Calalase yield by Serratia

  10. Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms

    SciTech Connect

    Jason S. Lewis

    2012-04-09

    Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) [1,2]. These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) [2]. A 'click' chemistry approach has been used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) [3]. Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles [1]. Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust, versatile, and multi

  11. Imatinib Analogs as Potential Agents for PET Imaging of Bcr-Abl/c-KIT Expression at a Kinase Level

    PubMed Central

    Peng, Zhenghong; Maxwell, David S.; Sun, Duoli; Bhanu Prasad, Basvoju A.; Pal, Ashutosh; Wang, Shimei; Balatoni, Julius; Ghosh, Pradip; Lim, Seok T.; Volgin, Andrei; Shavrin, Aleksander; Alauddin, Mian M.; Gelovani, Juri G.; Bornmann, William G.

    2014-01-01

    We synthesized two series of imatinib mesylate (STI-571) analogs to develop a Bcr-Abl and c-KIT receptor-specific labeling agent for positron emission tomography (PET) imaging to measure Bcr-Abl and c-KIT expression levels in a mouse model. The methods of molecular modeling, synthesis of STI-571 and its analogs, in vitro kinase assays, and radiolabeling are described. Molecular modeling revealed that these analogs bind the same Bcr-Abl and c-KIT binding sites as those bound by STI-571. The analogs potently inhibit the tyrosine kinase activity of Bcr-Abl and c-KIT, similarly to STI-571. [18F]-labeled STI-571 was prepared with high specific activity (75 GBq/μmol) by nucleophilic displacement and an average radiochemical yield of 12%. [131I]-labeled STI-571 was prepared with high purity (>95%) and an average radiochemical yield of 23%. The uptake rates of [18F]-STI-571 in K562 cells expressing Abl and in U87WT cells overexpressing c-KIT were significantly higher than those in the U87 cell and could be inhibited by STI-71 (confirming the specificity of uptake). PET scans of K562 and U87WT tumor-bearing mice with [18F]-STI-571 as a contrast agent showed visible tumor uptake and tumor-to-non-target contrast. PMID:24280068

  12. A double-injection technique for in vivo measurement of dopamine D2-receptor density in monkeys with 3-(2'-( sup 18 F)fluoroethyl)spiperone and dynamic positron emission tomography

    SciTech Connect

    Huang, S.C.; Bahn, M.M.; Barrio, J.R.; Hoffman, J.M.; Satyamurthy, N.; Hawkins, R.A.; Mazziotta, J.C.; Phelps, M.E. )

    1989-12-01

    Dopamine D2-receptor density in striatum of monkey was measured with 3-(2'-({sup 18}F)fluoroethyl)spiperone (FESP) and dynamic positron emission tomography (PET), using a double-injection technique. A first bolus of high specific activity (SA) FESP (5 mCi; approximately equal to 1 Ci/mumol) was injected i.v.; 90 min later, a second bolus of lower SA FESP (5 mCi; approximately equal to 0.04 Ci/mumol) was injected. A dynamic PET study was performed to measure the kinetics of FESP in striatum over 180 min, and the metabolite-corrected concentration of FESP in plasma as a function of time was obtained from arterial blood samples. A nonlinear compartmental model that took into account the saturability of the receptor binding was used to describe the kinetics of FESP in striatum. Model parameters were estimated by regression with a constraint based on information about the equilibrium dissociation constant of the ligand-receptor binding. Dopamine D2-receptor density in striatum was estimated to be 25.9 +/- 12.7 pmol/g in seven Macaca nemestrina monkeys. The method does not require the use of cerebellum as a reference tissue region and an estimate of dopamine D2-receptor density can be obtained from a single study.

  13. D-ribulose-5-phosphate 3-epimerase: Cloning and heterologous expression of the spinach gene, and purification and characterization of the recombinant enzyme

    SciTech Connect

    Chen, Y.R.; Hartman, F.C.; Lu, T.Y.S.; Larimer, F.W.

    1998-09-01

    The authors have achieved, to their knowledge, the first high-level heterologous expression of the gene encoding D-ribulose-5-phosphate 3-epimerase from any source, thereby permitting isolation and characterization of the epimerase as found in photosynthetic organisms. The extremely labile recombinant spinach (Spinacia oleracea L.) enzyme was stabilized by DL-{alpha}-glycerophosphate or ethanol and destabilized by D-ribulose-5-phosphate or 2-mercaptoethanol. Despite this lability, the unprecedentedly high specific activity of the purified material indicates that the structural integrity of the enzyme is maintained throughout isolation. Ethylenediaminetetraacetate and divalent metal cations did not affect epimerase activity, thereby excluding a requirement for the latter in catalysis. As deduced from the sequence of the cloned spinach gene and the electrophoretic mobility under denaturing conditions of the purified recombinant enzyme, its 25-kD subunit size was about the same as that of the corresponding epimerases of yeast and mammals. However, in contrast to these other species, the recombinant spinach enzyme was octameric rather than dimeric, as assessed by gel filtration and polyacrylamide gel electrophoresis under nondenaturing conditions. Western-blot analyses with antibodies to the purified recombinant enzyme confirmed that the epimerase extracted from spinach leaves is also octameric.

  14. Purification and Characterization of a Novel Intracellular Sucrase Enzyme of Leishmania donovani Promastigotes

    PubMed Central

    Singh, Arpita; Mandal, Debjani

    2016-01-01

    The promastigote stage of Leishmania resides in the sand fly gut, enriched with sugar molecules. Recently we reported that Leishmania donovani possesses a sucrose uptake system and a stable pool of intracellular sucrose metabolizing enzyme. In the present study, we purified the intracellular sucrase nearly to its homogeneity and compared it with the purified extracellular sucrase. The estimated size of intracellular sucrase is ~112 kDa by gel filtration chromatography, native PAGE, and substrate staining. However, in SDS-PAGE, the protein is resolved at ~56 kDa, indicating the possibility of a homodimer in its native state. The kinetics of purified intracellular sucrase shows its higher substrate affinity with a K m of 1.61 mM than the extracellular form having a K m of 4.4 mM. The highly specific activity of intracellular sucrase towards sucrose is optimal at pH 6.0 and at 30°C. In this report the purification and characterization of intracellular sucrase provide evidence that sucrase enzyme exists at least in two different forms in Leishmania donovani promastigotes. This intracellular sucrase may support further intracellular utilization of transported sucrose. PMID:27190649

  15. Recombinant Human Factor IX Produced from Transgenic Porcine Milk

    PubMed Central

    Lee, Meng-Hwan; Lin, Yin-Shen; Tu, Ching-Fu; Yen, Chon-Ho

    2014-01-01

    Production of biopharmaceuticals from transgenic animal milk is a cost-effective method for highly complex proteins that cannot be efficiently produced using conventional systems such as microorganisms or animal cells. Yields of recombinant human factor IX (rhFIX) produced from transgenic porcine milk under the control of the bovine α-lactalbumin promoter reached 0.25 mg/mL. The rhFIX protein was purified from transgenic porcine milk using a three-column purification scheme after a precipitation step to remove casein. The purified protein had high specific activity and a low ratio of the active form (FIXa). The purified rhFIX had 11.9 γ-carboxyglutamic acid (Gla) residues/mol protein, which approached full occupancy of the 12 potential sites in the Gla domain. The rhFIX was shown to have a higher isoelectric point and lower sialic acid content than plasma-derived FIX (pdFIX). The rhFIX had the same N-glycosylation sites and phosphorylation sites as pdFIX, but had a higher specific activity. These results suggest that rhFIX produced from porcine milk is physiologically active and they support the use of transgenic animals as bioreactors for industrial scale production in milk. PMID:24955355

  16. Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides

    SciTech Connect

    Menapace, E.; Birattari, C.; Bonardi, M.L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-24

    The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

  17. Synthesis and Evaluation of Astatinated N-[2-(Maleimido)ethyl]-3-(trimethylstannyl)benzamide Immunoconjugates.

    PubMed

    Aneheim, Emma; Gustafsson, Anna; Albertsson, Per; Bäck, Tom; Jensen, Holger; Palm, Stig; Svedhem, Sofia; Lindegren, Sture

    2016-03-16

    Effective treatment of metastasis is a great challenge in the treatment of different types of cancers. Targeted alpha therapy utilizes the short tissue range (50-100 μm) of α particles, making the method suitable for treatment of disseminated occult cancers in the form of microtumors or even single cancer cells. A promising radioactive nuclide for this type of therapy is astatine-211. Astatine-211 attached to tumor-specific antibodies as carrier molecules is a system currently under investigation for use in targeted alpha therapy. In the common radiolabeling procedure, astatine is coupled to the antibody arbitrarily on lysine residues. By instead coupling astatine to disulfide bridges in the antibody structure, the immunoreactivity of the antibody conjugates could possibly be increased. Here, the disulfide-based conjugation was performed using a new coupling reagent, maleimidoethyl 3-(trimethylstannyl)benzamide (MSB), and evaluated for chemical stability in vitro. The immunoconjugates were subsequently astatinated, resulting in both high radiochemical yield and high specific activity. The MSB-conjugate was shown to be stable with a long shelf life prior to the astatination. In a comparison of the in vivo distribution of the new immunoconjugate with other tin-based immunoconjugates in tumor-bearing mice, the MSB conjugation method was found to be a viable option for successful astatine labeling of different monoclonal antibodies. PMID:26791409

  18. Synthesis and characterization of europium(III) nanoparticles for time-resolved fluoroimmunoassay of prostate-specific antigen

    NASA Astrophysics Data System (ADS)

    Härmä, Harri; Keränen, Anne-Maria; Lövgren, Timo

    2007-02-01

    Recent advances in the fabrication and bioconjugation of nanometre-sized lanthanide(III) chelate particles have led to robust high specific activity labels. This paper describes the synthesis and characterization of lanthanide(III) nanoparticle labels and the use of a nanoparticle in a bioaffinity assay system. Two europium(III) nanoparticles were prepared using an extremely simple, inexpensive and fast agglomeration strategy. A silica-stabilized nanoparticle was synthesized from hydrophobic tris(dibenzoylmethane)-mono(phenanthroline) and tris(dibenzoylmethane)-mono(5-aminophenanthroline) europium(III) chelates in aqueous solution. In addition, a naphthoyl trifluoroacetone:tri-n-octylphosphineoxide:sodium dodecyl sulfate europium(III) complex was agglomerated in water. The particle sizes ranged from 62 to 140 nm in diameter. The silica-stabilized particle was further coated with a monoclonal antibody. The analytical performance of the bioconjugated nanoparticle label was evaluated in a model sandwich immunoassay of prostate-specific antigen. The detection limit of human prostate-specific antigen was 28 ng l-1, 850 fM, in a microtiter plate format using time-resolved fluorometry. The coefficient of variation ranged from 1 to 9%. The novel nanoparticle label improves the specific activity of existing lanthanide(III) nanoparticle labels and simplifies the preparation route. In addition, prepared high-density nanoparticle labels using lanthanide(III) chelates or other specific fluorochromes have potential applications in a number of other fields.

  19. Risk assessment for the transportation of radioactive zeolite liners

    SciTech Connect

    Not Available

    1982-01-01

    The risk is estimated for the shipment of radioactive zeolite liners in support of the Zeolite Vitrification Demonstration Program currently underway at Pacific Northwest Laboratory under the sponsorship of the US Department of Energy. This program will establish the feasibility of zeolite vitrification as an effective means of immobilizing high-specific-activity wastes. In this risk assessment, it is assumed that two zeolite liners, each loaded around July 1, 1981 to 60,000 Ci, will be shipped by truck around January 1, 1982. However, to provide a measure of conservatism, each liner is assumed to initially hole 70,000 Ci, with the major radioisotopes as follow: /sup 90/Sr = 3000 Ci, /sup 134/Cs = 7000 Ci, /sup 137/Cs = 60,000 Ci. Should shipment take place with essentially no delay after initial loading (regardless of loading date), the shipment loading would be only 2.7% higher than that for the assumed six-month delay. This would negligibly affect the overall risk. As a result of this risk assessment, it is concluded that the transport of the radioactive zeolite liners from TMI to PNL by truck can be conducted at an insignificant level of risk to the public.

  20. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    SciTech Connect

    Hicks, G.R.; Rayle, D.L.; Jones, A.M.; Lomax, T.L. )

    1989-07-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-(7-{sup 3}H)IAA(({sup 3}H)N{sub 3}IAA), in a manner similar to the accumulation of ({sup 3}H)IAA. The association of the ({sup 3}H)N{sub 3}IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of ({sup 3}H)N{sub 3}IAA to plasma membrane vesicles prior to exposure to UV light and detected by subsequent NaDodSO{sub 4}/PAGE and fluorography. When the reaction temperature was lowered to {minus}196{degree}C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.

  1. Radiolabeling and evaluation of 64Cu-DOTA-F56 peptide targeting vascular endothelial growth factor receptor 1 in the molecular imaging of gastric cancer

    PubMed Central

    Zhu, Hua; Zhao, Chuanke; Liu, Fei; Wang, Lixin; Feng, Junnan; Zhou, Zheng; Qu, Like; Shou, Chengchao; Yang, Zhi

    2015-01-01

    Noninvasive imaging of vascular endothelial growth factor receptor 1 (VEGFR1) remains a great challenge in early diagnosis of gastric cancer. Here we reported the synthesis, radiolabeling, and evaluation of a novel 64Cu-radiolabeled peptide for noninvasive positron emission tomography (PET) imaging of VEGFR1 positive gastric cancer. The binding of modified peptide WHSDMEWWYLLG (termed as F56) to VEGER-1 expressed in gastric cancer cell BCG823 has been confirmed by immune-fluorescence overlap. DOTA-F56 was designed and prepared by solid-phase synthesis and folded in vitro. 64Cu-DOTA-F56 was synthesized in high radiochemical yield and high specific activity (S.A. up to 255.6 GBq/mmol). It has excellent in vitro stability. Micro-PET imaging of 64Cu-DOTA-F56 identifies tumor in BCG823 tumor-bearing mice, while that of 18F-FDG does not. Immunohistochemical analysis of excised BCG823 xenograft showed colocalization between the PET images and the staining of VEGFR1. These results demonstrated that 64Cu-DOTA-F56 peptide has potential as a noninvasive imaging agent in VEGFR1 positive tumors. PMID:26807312

  2. Self-assembly of carbon nanotubes and antibodies on tumours for targeted, amplified delivery

    PubMed Central

    Mulvey, J. Justin; Villa, Carlos H.; McDevitt, Michael R.; Escorcia, Freddy E.; Casey, Emily; Scheinberg, David A.

    2013-01-01

    Single-walled carbon nanotubes (SWNTs) can deliver imaging agents or drugs to tumours and offer significant advantages over approaches based on antibodies or other nanomaterials. In particular, the nanotubes can carry a substantial amount of cargo (100 times more than a monoclonal antibody), but can still be rapidly eliminated from circulation by renal filtration, like a small molecule, due to their high aspect ratio. Here we show that SWNTs can target tumours in a two-step approach in which nanotubes modified with morpholino oligonucleotide sequences bind to cancer cells that have been pre-targeted with antibodies modified with oligonucleotide strands complementary to those on the nanotubes. The nanotubes can carry fluorophores or radioisotopes, and were shown to selectively bind to cancer cells in vitro and in tumour-bearing xenografted mice. The binding process is also found to lead to antigen capping and internalization of the antibody/nanotube complexes. The nanotube conjugates were labelled with both alpha-particle and gamma-ray emitting isotopes, at high specific activities. Conjugates labelled with alpha-particle generating 225Ac were found to clear rapidly, thus mitigating radioisotope toxicity, and were shown to be therapeutically effective in vivo. PMID:24077028

  3. Hyperexpression and purification of Escherichia coli adenylate cyclase using a vector designed for expression of lethal gene products.

    PubMed

    Reddy, P; Peterkofsky, A; McKenney, K

    1989-12-25

    We describe the construction of a new generation of vectors (pRE) for the hyperexpression of lethal gene products such as adenylate cyclase in Escherichia coli. The pRE vectors are based on the lambda PL promoter and lambda cII ribosome binding site described by Shimatake and Rosenberg (Nature, 292, 128-132, 1981). They have a unique NdeI restriction endonuclease site 3' of the lambda cII ribosome binding site that includes the ATG initiation codon, multilinker cloning sites 3' to the NdeI site, and two lambda transcription terminators 5' and 3' of the lambda PL promoter to eliminate nonspecific transcription and reduce leaky PL transcription, respectively. For hyperexpression of adenylate cyclase, tight control of transcription was necessary since elevation of cAMP levels above the physiological range is lethal to E. coli. Lethality associated with the overproduction of adenylate cyclase was shown to be mediated through the cAMP receptor protein. We used this expression system to overproduce adenylate cyclase 7500 fold, corresponding to 30% of the total cellular protein. Under these conditions the enzyme precipitated with significant loss of activity. Reducing the rate and amount of adenylate cyclase expression to 16% of the total cell protein produced one fourth of the enzyme in a soluble form with high specific activity. The soluble adenylate cyclase was purified to near homogeneity. PMID:2557591

  4. Synthesis and radiolabeling of a somatostatin analog for multimodal imaging

    NASA Astrophysics Data System (ADS)

    Edwards, W. Barry; Liang, Kexian; Xu, Baogang; Anderson, Carolyn J.; Achilefu, Samuel

    2006-02-01

    A new multimodal imaging agent for imaging the somatostatin receptor has been synthesized and evaluated in vitro and in vivo. A somatostatin analog, conjugated to both 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaceticacid (DOTA) and cypate (BS-296), was synthesized entirely on the solid phase (Fmoc) and purified by RP-HPLC. DOTA was added as a ligand for radiometals such as 64Cu or 177Lu for either radio-imaging or radiotherapy respectively. Cytate, a cypatesomatostatin analog conjugate, has previously demonstrated the ability to visualize somatostatin receptor rich tumor xenografts and natural organs by optical imaging techniques. BS-296 exhibited low nanomolar inhibitory capacity toward the binding of radiolabeled somatostatin analogs in cell membranes enriched in the somatostatin receptor, demonstrating the high affinity of this multimodal imaging peptide and indicating its potential as a molecular imaging agent. 64Cu, an isotope for diagnostic imaging and radiotherapy, was selected as the isotope for radiolabeling BS-296. BS-296 was radiolabeled with 64Cu in high specific activity (200 μCi/μg) in 90% radiochemical yield. Addition of 2,5-dihydroxybenzoic acid (gentisic acid) prevented radiolysis of the sample, allowing for study of the 64Cu -BS-296 the day following radiolabeling. Furthermore, inclusion of DMSO at a level of 20% was found not to interfere with radiolabeling yields and prevented the adherence of 64Cu -BS-296 to the walls of the reaction vessel.

  5. New Glucocyclic RGD Dimers for Positron Emission Tomography Imaging of Tumor Integrin Receptors.

    PubMed

    Lee, Ji Woong; Park, Ji-Ae; Lee, Yong Jin; Shin, Un Chol; Kim, Suhng Wook; Kim, Byung Il; Lim, Sang Moo; An, Gwang Il; Kim, Jung Young; Lee, Kyo Chul

    2016-08-01

    Most studies of radiolabeled arginine-glycine-aspartic acid (RGD) peptides have shown in vitro affinity for integrin ανβ3, allowing for the targeting of receptor-positive tumors in vivo. However, major differences have been found in the pharmacokinetic profiles of different radiolabeled RGD peptide analogs. The purposes of this study were to prepare (64)Cu-DOTA-gluco-E[c(RGDfK)]2 (R8), (64)Cu-NOTA-gluco-E[c(RGDfK)]2 (R9), and (64)Cu-NODAGA-gluco-E[c(RGDfK)]2 (R10) and compare their pharmacokinetics and tumor imaging properties using small-animal positron emission tomography (PET). All three compounds were produced with high specific activity within 10 minutes. The IC50 values were similar for all the substances, and their affinities were greater than that of c(RGDyK). R8, R9, and R10 were stable for 24 hours in human and mouse serums and showed high uptake in U87MG tumors with high tumor-to-blood ratios. Compared to the control, a cyclic RGD peptide dimer without glucosamine, R10, showed low uptake in the liver. Because of their good imaging qualities and improved pharmacokinetics, (64)Cu-labeled dimer RGD conjugates (R8, R9, and R10) may have potential applications as PET radiotracers. R9 (NOTA) with highly in vivo stability consequentially showed an improved PET tumor uptake than R8 (DOTA) or R10 (NODAGA). PMID:27403677

  6. 18F-Labeled Silicon-Based Fluoride Acceptors: Potential Opportunities for Novel Positron Emitting Radiopharmaceuticals

    PubMed Central

    Bernard-Gauthier, Vadim; Wängler, Carmen; Wängler, Bjoern; Schirrmacher, Ralf

    2014-01-01

    Background. Over the recent years, radiopharmaceutical chemistry has experienced a wide variety of innovative pushes towards finding both novel and unconventional radiochemical methods to introduce fluorine-18 into radiotracers for positron emission tomography (PET). These “nonclassical” labeling methodologies based on silicon-, boron-, and aluminium-18F chemistry deviate from commonplace bonding of an [18F]fluorine atom (18F) to either an aliphatic or aromatic carbon atom. One method in particular, the silicon-fluoride-acceptor isotopic exchange (SiFA-IE) approach, invalidates a dogma in radiochemistry that has been widely accepted for many years: the inability to obtain radiopharmaceuticals of high specific activity (SA) via simple IE. Methodology. The most advantageous feature of IE labeling in general is that labeling precursor and labeled radiotracer are chemically identical, eliminating the need to separate the radiotracer from its precursor. SiFA-IE chemistry proceeds in dipolar aprotic solvents at room temperature and below, entirely avoiding the formation of radioactive side products during the IE. Scope of Review. A great plethora of different SiFA species have been reported in the literature ranging from small prosthetic groups and other compounds of low molecular weight to labeled peptides and most recently affibody molecules. Conclusions. The literature over the last years (from 2006 to 2014) shows unambiguously that SiFA-IE and other silicon-based fluoride acceptor strategies relying on 18F− leaving group substitutions have the potential to become a valuable addition to radiochemistry. PMID:25157357

  7. Antibody Therapeutics in Oncology

    PubMed Central

    Wold, Erik D; Smider, Vaughn V; Felding, Brunhilde H

    2016-01-01

    One of the newer classes of targeted cancer therapeutics is monoclonal antibodies. Monoclonal antibody therapeutics are a successful and rapidly expanding drug class due to their high specificity, activity, favourable pharmacokinetics, and standardized manufacturing processes. Antibodies are capable of recruiting the immune system to attack cancer cells through complement-dependent cytotoxicity or antibody dependent cellular cytotoxicity. In an ideal scenario the initial tumor cell destruction induced by administration of a therapeutic antibody can result in uptake of tumor associated antigens by antigen-presenting cells, establishing a prolonged memory effect. Mechanisms of direct tumor cell killing by antibodies include antibody recognition of cell surface bound enzymes to neutralize enzyme activity and signaling, or induction of receptor agonist or antagonist activity. Both approaches result in cellular apoptosis. In another and very direct approach, antibodies are used to deliver drugs to target cells and cause cell death. Such antibody drug conjugates (ADCs) direct cytotoxic compounds to tumor cells, after selective binding to cell surface antigens, internalization, and intracellular drug release. Efficacy and safety of ADCs for cancer therapy has recently been greatly advanced based on innovative approaches for site-specific drug conjugation to the antibody structure. This technology enabled rational optimization of function and pharmacokinetics of the resulting conjugates, and is now beginning to yield therapeutics with defined, uniform molecular characteristics, and unprecedented promise to advance cancer treatment. PMID:27081677

  8. Synthesis and metabolism of pheromones and pheromone analogues

    SciTech Connect

    Ding, Y.S.

    1987-01-01

    (9, 10-/sup 3/H/sub 2/)Z9-14:Ac was synthesized at high specific activity (/sup 3/H, 58 Ci/mmole) by partial tritiation of the corresponding alkyne and was converted to the labeled Z9-14:OH and Z9-14:Al to study tissue specificity of acetate esterase (E), alcohol oxidase (OX), and aldehyde dehydrogenase (ALDH) in male and female Heliothis virescens. Soluble and membrane-associated enzyme activities were determined by radio-TLC assays. Compounds of the tritium-labeled Z11-16 series were synthesized and their in vitro fates examined as well. In order to achieve an alternative approach in which (1) pheromone receptor proteins would be stoichiometrically and irreversibly modified, or (2) pheromone-catabolizing enzymes are inactivated by tight-binding or irreversible inhibitors, we have designed analogues of pheromones of lepidopterous insect pests and assayed their biological activity in vitro and in vivo. Various fluorinated molecules such as acyl fluorides, fluoroolefins, 2-fluoro aldehydes, 2,2-difluoro aldehydes and trifluoromethyl ketones were synthesized. The synthesis of some other functional groups such as cyclopropanones, cyclopropanols, cyclopropyl carbinols, cyclopropyl aldehydes and Michael acceptors will also be discussed.

  9. Waste Management at the Nevada Test Site Year 2002: Current Status

    SciTech Connect

    Becker, Bruce, D.; Gertz, Carl, P.; Clayton, Wendy, A.; Carilli, Jhon, T.; Crowe, Bruce M.

    2003-02-24

    The performance attributes of the U. S. Department of Energy's National Nuclear Security Administration Nevada Site Office Low-level Radioactive Waste (LLW) disposal facilities located at the Nevada Test Site transcend those of any other LLW disposal site in the United States. Situated at the southern end of the Great Basin, 244 meters (800 feet) above the water table, the Area 5 Radioactive Waste Management Site (RWMS) has utilized a combination of engineered shallow land disposal cells and deep augured shafts to dispose a variety of waste streams. These include high volume low-activity waste, classified material, and high-specific activity special case waste. Fifteen miles north of Area 5 is the Area 3 RWMS. Here bulk LLW disposal takes place in subsidence craters formed from underground testing of nuclear weapons. Earliest records indicate that documented LLW disposal activities have occurred at the Area 5 and Area 3 RWMSs since 1961 and 1968, respectively. However, these activities have only been managed under a formal program since 1978. This paper describes the technical attributes of the facilities, present and future capacities and capabilities, and provides a description of the process from waste approval to final disposition. The paper also summarizes the current status of the waste disposal operations.

  10. Waste Management at the Nevada Test Site Fiscal Year 2001 Current Status

    SciTech Connect

    B. D. Becker; W. A. Clayton; B. M. Crowe

    2002-05-01

    The performance objectives of the U. S. Department of Energy's National Nuclear Security Administration Nevada Operations Office (NNSA/NV) Low-level Radioactive Waste (LLW) disposal facilities located at the Nevada Test Site transcend those of any other radioactive waste disposal site in the United States. Situated at the southern end of the Great Basin, 244 meters (800 feet) above the water table, the Area 5 Radioactive Waste Management Site (RWMS) has utilized a combination of engineered shallow land disposal cells and deep augured shafts to dispose a variety of waste streams. These include high volume low-activity waste, classified radioactive material, and high-specific-activity special case waste. Fifteen miles north of Area 5 is the Area 3 RWMS. Here bulk LLW disposal takes place in subsidence craters formed from underground testing of nuclear weapons. Earliest records indicate that documented LLW disposal activities have occurred at the Area 5 and Area 3 RWMSs since 1961 and 1 968, respectively. However, these activities have only been managed under a formal program since 1978. This paper describes the technical attributes of the facilities, present and future capacities and capabilities, and provides a description of the process from waste approval to final disposition. The paper also summarizes the current status of the waste disposal operations.

  11. Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides

    NASA Astrophysics Data System (ADS)

    Menapace, E.; Birattari, C.; Bonardi, M. L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-01

    The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

  12. Specific binding sites for muramyl peptides on murine macrophages

    SciTech Connect

    Silverman, D.H.S.; Krueger, J.M.; Karnovsky, M.L.

    1986-03-15

    Two radiolabeled (/sup 125/I) muramyl peptide derivatives of high specific activity were prepared: a tripeptide with an iodinated C-terminal tyrosine methyl ester (Ligand I), and a muramyl tripeptide with a C-terminal lysine derivatized with Bolton-Hunter reagent (Ligand II). These were used to characterize binding of muramyl peptides to monolayers of murine macrophages. Saturable high-affinity binding to resident, caseinate-elicited, and Listeria-activated peritoneal cells was observed with both radioligands. Binding affinities varied with the state of activation of the macrophages, and K/sub D/ values ranged from 48 +/- 33 pM (for resident macrophages, Ligand I) to 1020 +/- 90 pM (for activated macrophages, Ligand II). Specific binding sites were also found on a macrophage-derived cell line. The ability of several unlabeled muramyl peptides to compete with Ligands I and II for their binding sites was tested. Competition was stereospecific and correlated with known biological activities of these compounds (i.e., immunoadjuvanticity, pyrogenicity, and somnogenicity). The sites identified here for Ligands I and II may mediate some of the effects that muramyl peptides have previously been demonstrated to have on macrophages.

  13. Evidence of a saturable hepatic receptor for mouse monoclonal antibodies

    SciTech Connect

    De Nardo, G.L.; De Nardo, S.J.; Peng, J.S.; O'Grady, L.F.; Mills, S.L.; Epstein, A.L.; Cardiff, R.D.

    1985-05-01

    Monoclonal antibodies (MAb) can be labeled with I-123 at high specific activities, so that large amounts of radioactivity attached to small amounts of protein can be injected for radioimmunoimaging. This conserves antibody and decreases the opportunity for foreign protein reactions and target tissue binding site saturation. In order to assess the effects on pharmacokinetics and imaging, the authors administered microgram amounts of I-123-MAb (Lyn-1, IgG2a or B6.01, IgGl with and following 4-5 milligram preloading with MAb on separate occasions to 4 patients with a target tumor (B cell lymphoma) and 2 patients without a target tumor (breast cancer). Pharmacokinetics were observed in blood and urine by counting whole samples and HPLC fractions of these samples and in organs by serial imaging. Early blood clearance and urinary excretion were faster after injection of microgram amounts of MAb, but subsequently were comparable to those obtained after preload. This paper concludes that the amount of administered MAb dramatically influences the pharmacokinetics of mouse MAb. Saturable hepatic Fc receptors are probably the source of these observations. Reports of accelerated deiodination of MAb are related to this phenomenon. Optimal imaging and treatment with MAb requires saturation of these hepatic receptors.

  14. Calibration of an Ultra-Low-Background Proportional Counter for Measuring 37Ar

    SciTech Connect

    Seifert, Allen; Aalseth, Craig E.; Bonicalzi, Ricco; Bowyer, Ted W.; Day, Anthony R.; Fuller, Erin S.; Haas, Derek A.; Hayes, James C.; Hoppe, Eric W.; Humble, Paul H.; Keillor, Martin E.; LaFerriere, Brian D.; Mace, Emily K.; McIntyre, Justin I.; Merriman, Jason H.; Miley, Harry S.; Myers, Allan W.; Orrell, John L.; Overman, Cory T.; Panisko, Mark E.; Williams, Richard M.

    2013-08-08

    Abstract. An ultra-low-background proportional counter (ULBPC) design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electrochemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) constructed at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with 14C/3H, age-dating of groundwater with 39Ar, and soil-gas assay for 37Ar to support On-Site Inspection (OSI). On-Site Inspection is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of 37Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of 37Ar samples over a broad range of pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for 37Ar soil gas background studies.

  15. Calibration of an ultra-low-background proportional counter for measuring {sup 37}Ar

    SciTech Connect

    Seifert, A.; Aalseth, C. E.; Bonicalzi, R. M.; Bowyer, T. W.; Day, A. R.; Fuller, E. S.; Haas, D. A.; Hayes, J. C.; Hoppe, E. W.; Humble, P. H.; Keillor, M. E.; LaFerriere, B. D.; Mace, E. K.; McIntyre, J. I.; Merriman, J. H.; Miley, H. S.; Myers, A. W.; Orrell, J. L.; Overman, C. T.; Panisko, M. E.; and others

    2013-08-08

    An ultra-low-background proportional counter design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electro-chemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with {sup 14}C/{sup 3}H, age-dating of groundwater with {sup 39}Ar, and soil-gas assay for {sup 37}Ar to support On-Site Inspection (OSI). On-Site Inspection is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of {sup 37}Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of {sup 37}Ar samples over a broad range of proportional counter operating pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for {sup 37}Ar soil gas background studies.

  16. α/β Hydrolase Domain-containing 6 (ABHD6) Degrades the Late Endosomal/Lysosomal Lipid Bis(monoacylglycero)phosphate*

    PubMed Central

    Pribasnig, Maria A.; Mrak, Irina; Grabner, Gernot F.; Taschler, Ulrike; Knittelfelder, Oskar; Scherz, Barbara; Eichmann, Thomas O.; Heier, Christoph; Grumet, Lukas; Kowaliuk, Jakob; Romauch, Matthias; Holler, Stefan; Anderl, Felix; Wolinski, Heimo; Lass, Achim; Breinbauer, Rolf; Marsche, Gunther; Brown, J. Mark; Zimmermann, Robert

    2015-01-01

    α/β Hydrolase domain-containing 6 (ABHD6) can act as monoacylglycerol hydrolase and is believed to play a role in endocannabinoid signaling as well as in the pathogenesis of obesity and liver steatosis. However, the mechanistic link between gene function and disease is incompletely understood. Here we aimed to further characterize the role of ABHD6 in lipid metabolism. We show that mouse and human ABHD6 degrade bis(monoacylglycero)phosphate (BMP) with high specific activity. BMP, also known as lysobisphosphatidic acid, is enriched in late endosomes/lysosomes, where it plays a key role in the formation of intraluminal vesicles and in lipid sorting. Up to now, little has been known about the catabolism of this lipid. Our data demonstrate that ABHD6 is responsible for ∼90% of the BMP hydrolase activity detected in the liver and that knockdown of ABHD6 increases hepatic BMP levels. Tissue fractionation and live-cell imaging experiments revealed that ABHD6 co-localizes with late endosomes/lysosomes. The enzyme is active at cytosolic pH and lacks acid hydrolase activity, implying that it degrades BMP exported from acidic organelles or de novo-formed BMP. In conclusion, our data suggest that ABHD6 controls BMP catabolism and is therefore part of the late endosomal/lysosomal lipid-sorting machinery. PMID:26491015

  17. ¹¹¹In-DTPA⁰-octreotide (Octreoscan), ¹³¹I-MIBG and other agents for radionuclide therapy of NETs.

    PubMed

    Bomanji, Jamshed B; Papathanasiou, Nikolaos D

    2012-02-01

    This paper is a critical review of the literature on NET radionuclide therapy with (111)In-DTPA(0)-octreotide (Octreoscan) and (131)I-MIBG, focusing on efficacy and toxicity. Some potential future applications and new candidate therapeutic agents are also mentioned. Octreoscan has been a pioneering agent for somatostatin receptor radionuclide therapy. It has achieved symptomatic responses and disease stabilization, but it is now outperformed by the corresponding β-emitter agents (177)Lu-DOTATATE and (90)Y-DOTATOC. (131)I-MIBG is the radionuclide therapy of choice for inoperable or metastatic phaeochromocytomas/paragangliomas, which avidly concentrate this tracer via the noradrenaline transporter. Symptomatic, biochemical and tumour morphological response rates of 50-89%, 45-74% and 27-47%, respectively, have been reported. (131)I-MIBG is a second-line radiopharmaceutical for treatment of enterochromaffin carcinoids, mainly offering the benefit of amelioration of hormone-induced symptoms. High specific activity, non-carrier-added (131)I-MIBG and meta-astato((211)At)-benzylguanidine (MABG) are tracers with potential for enhanced therapeutic efficacy, yet their integration into clinical practice awaits further exploration. Amongst other promising agents, radiolabelled exendin analogues show potential for imaging and possibly therapy of insulinomas, while preclinical studies are currently evaluating DOTA peptides targeting the CCK-2/gastrin receptors that are overexpressed by medullary thyroid carcinoma cells. PMID:22388626

  18. Coenzyme B-12-dependent reactions. Part IV. Observations on the purification of ethanolamine ammonia-lyase.

    PubMed

    Joblin, K N; Johnson, A W; Lappert, M F; Wallis, O C

    1976-11-01

    Purification of ethanolamine ammonia-lyase (EC 4.3.1.7) from a Clostridium sp. grown at the University of Sussex, U.K. and the National Institutes of Health, U.S.A., has been compared and an improved isotopic assay for the enzyme has been developed. Successful purification of this enzyme from Sussex-grown cells requires modification of the published procedure (Kaplan and Stadtman (1968) J. Biol, Chem. 243, 1787-1793) principally a 70% decrease in volume during precipitation with 0.4 M NaCl. This modification also increases the yield from N.I.H.-grown cells. Purified enzyme, resolved of inactive cobalamins, has the same high specific activity from both sources and behaves in the same way on disc gel electrophoresis. Sussex enzyme, before resolution, has less than 20% of the specific activity of unresolved N.I.H. enzyme and contains over 50% more inactive cobalamin. The bound cobalamin from both preparations has been identified as a "base-on" Co11 psi-cobalamin. PMID:186123

  19. Locating tritium sources in a research reactor building.

    PubMed

    Fukui, Masami

    2005-10-01

    Despite renovation of the D2O facility, tritium concentrations in the condensates of reactor room air showed tens of Bq mL before venting resumption on July 1997. This suggested the presence of tritium sources in the research reactor-containment building. An investigation was therefore initiated to locate the source and determine the distribution of tritium in the containment building. Air monitoring in the working area using a dish of water placed in the building suggested that the source of tritium was near the reactor core. Monitoring exhaust air from the two facilities (a cold neutron source and a D(2)O tank) showed high specific activity on the order of 10 Bq mL(-1), suggesting the presence of tritium in condensates near the reactor core. The major concern was whether the leakage of liquid deuterium (4 L) and heavy water (2 x 10(3) L) used as a moderator had occurred. The concentration of tritium in condensates has not increased over the past few years in either the exhaust line or working area, and the deuterium itself has not been found in the surrounding environment. The concentration of tritium measured using an ionization chamber after Ar decay was dependent on the thermal output of the research reactor, indicating that the tritium was produced by the irradiation process within shielding/moderator materials or cover gas with neutrons. PMID:16155451

  20. Synthesis and bioassay of radiolabeled, chiral probes for juvenile hormone receptor study

    SciTech Connect

    Eng, W.

    1987-01-01

    Four different types of compounds were synthesized for the detailed study on interactions between insect juvenile hormone (JH) and the corresponding binding proteins, receptor proteins and catabolic enzymes: (1) High specific activity /sup 3/H-labeled, chiral alkyldiazoacetates with their skeletons approaching those of natural JH I and JH II were synthesized as photoaffinity labels for probing JH receptor proteins in Lepidoptera. Compared with epoxy farnesyl diazoacetate (EFDA), epoxy bishomofarnesyl diazoacetate (EBDA) and epoxy homofarnesyl diazoacetate (EHDA) have largely increased affinity to Manduca sexta JH binding proteins (JHBP) as demonstrated by gel electrophoresis. (2) Chiral JH I and JH II acids, as well as 12-hydroxy-JH I and JH II were synthesized. The hydroxy groups in these compounds provide tether points for attachment to proteins to serve as antigens with most of the recognition sites preserved to be used in JH radioimmunoassays. (3) The first radioiodine-labeled JH, (/sup 125/I)-12-iodo-JH I, was synthesized, both in no-carrier-added and carrier-added forms, as one of the probes for JH receptor study. (4) Four alkylthioltrifluoropropanones with skeletons approaching that of JH III and functional groups mimicking the JH epoxide moiety were synthesized as inhibitors for JH esterase (JHE).

  1. A practical beryllium activation detector for measuring DD neutron yield from ICF targets

    SciTech Connect

    Murphy, T.J.

    1996-06-01

    A neutron activation detector based on the reaction {sup 9}Be(n,{alpha}){sup 6}He({beta}{sup {minus}}){sup 6}Li has been designed which could potentially allow DD yield determinations within a few minutes after an ICF implosion or other pulsed neutron event with precision comparable to methods currently in use in ICF experiments. The detector is based on previous work, but has been redesigned to allow use in a reentrant tube less than six inches in diameter, and to increase detection efficiency. The detector consists of beryllium rods imbedded in plastic scintillator and coupled to a photomultiplier tube. Neutrons interact with the beryllium to produce {sup 6}He, which decays by emission of a {beta}{sup {minus}} particle with a maximum energy of 3.51 MeV with a half life of 808 ms. The {beta}{sup {minus}} particles are counted, and a neutron yield is determined for the total activity produced. The short half life of {sup 6}He will result in high specific activity and allow quick determination of the amount of {sup 6}He produced.

  2. The advanced neutron source (ANS) - A proposed national resource for medical radioisotope production

    SciTech Connect

    Mirzadeh, S.; Knapp, F.F. Jr.; Alexander, C.W.

    1994-05-01

    The ANS will be a state-of-the-art 330-MWt research reactor which is under design for construction at ORNL. The ANS is heavy water cooled/moderated with a 21-day fuel cycle, scheduled for full power in year 2002. Radioisotope production facilities of the ANS include 3 hydraulic tubes (HT1, 2 and 4) and 4 vertical holes. The projected average thermal neutron flux at HT4 is 4.6 x 10E15 n/cm{sup 2}/sec., 2.3 times greater and more than doubling the capabilities of the ORNL-HFIR. The HT1 and HT3 have peak thermal fluxes {approximately}50% of that in the HFIR, with {theta}{sub n}(th){approx}1 x 10E15 n/cm{sup 2}/sec. The on-line access capability of the ANS vertical hole Facilities is unique and should offset the larger sample capacity of the HFIR reflector positions. The capabilities of the ANS facilities will offer increased availability and efficiency of radioisotope production, and a conservation of expensive target isotopes. To further illustrate the unique capabilities of the ANS, a comparison for the production of several key medical radioisotopes is given below. Because of the greatly increased flux, the ANS may also be an important facility for production of high specific activity [n,{gamma}] Mo-99, thus overcoming the major difficulties associated with the radioactive waste from fission-produced Mo-99.

  3. Recent progress in vitamin D metabolism and the chemistry of vitamin D metabolites

    SciTech Connect

    Schnoes, H.K.; DeLuca, H.F.

    1980-08-01

    The molecular mechanism of action of vitamin D and the elucidation of the vitamin D endocrine system are illustrated by selected examples of recent chemical work in our laboratories. One of these is the isolation and identification of vitamin D/sub 3/ as the antirachitic substance produced in irradiated skin. A second is the isolation and identification of the calcitroic acid, a major metabolite of 1,25-dihydroxyvitamin D/sub 3/ with potential function. A third is the isolation and identification of 25-hydroxyvitamin D/sub 3/-26,23-lactone, a major metabolite of vitamin D in the plasma of animals given large amounts of vitamin D. A fourth is a detailed study of 24,24-difluoro-25-hydroxyvitamin D/sub 3/ to test whether 24-hydroxylation plays an important role in the function of vitamin D. Other important developments include the chemical synthesis of high specific activity radioactive vitamin D metabolites for use in the elucidation of their molecular mechanism of action, cellular sites of action, and in quantitative metabolite assays. Finally, recent progress in synthetic methodology, providing a convenient route to 1..cap alpha..-hydroxylated vitamin D compounds, is summarized.

  4. New N-acyl-D-glucosamine 2-epimerases from cyanobacteria with high activity in the absence of ATP and low inhibition by pyruvate.

    PubMed

    Klermund, Ludwig; Groher, Anna; Castiglione, Kathrin

    2013-11-01

    N-Acetylneuraminic acid, an important component of glycoconjugates with various biological functions, can be produced from N-acetyl-D-glucosamine (GlcNAc) and pyruvate using a one-pot, two-enzyme system consisting of N-acyl-D-glucosamine 2-epimerase (AGE) and N-acetylneuraminate lyase (NAL). In this system, the epimerase catalyzes the conversion of GlcNAc into N-acetyl-D-mannosamine (ManNAc). However, all currently known AGEs have one or more disadvantages, such as a low specific activity, substantial inhibition by pyruvate and strong dependence on allosteric activation by ATP. Therefore, four novel AGEs from the cyanobacteria Acaryochloris marina MBIC 11017, Anabaena variabilis ATCC 29413, Nostoc sp. PCC 7120, and Nostoc punctiforme PCC 73102 were characterized. Among these enzymes, the AGE from the Anabaena strain showed the most beneficial characteristics. It had a high specific activity of 117±2 U mg(-1) at 37 °C (pH 7.5) and an up to 10-fold higher inhibition constant for pyruvate as compared to other AGEs indicating a much weaker inhibitory effect. The investigation of the influence of ATP revealed that the nucleotide has a more pronounced effect on the Km for the substrate than on the enzyme activity. At high substrate concentrations (≥200 mM) and without ATP, the enzyme reached up to 32% of the activity measured with ATP in excess. PMID:23850800

  5. Carbon-11 labeling of CP-126,998*: A radiotracer for in vivo studies of acetylcholinesterase

    SciTech Connect

    Musachio, J.L.; Flesher, J.E.; Scheffel, U.

    1996-05-01

    The study of acetylcholinesterase (AChE) via PET is of interest as reduced activity of this enzyme has been observed in Alzheimer`s disease. Our efforts to develop a radiotracer for mapping of AChE have focused on the N-benzylpiperidine benzisoxazole, CP-126,998, a highly potent (IC{sub 50}=0.48 nm) and selective inhibitor of AChE. High specific activity [C-11] CP-126,998 was synthesized (14 - 24% radiochemical yield, non-decay corrected) by treatment of the desmethyl precursor, CP-118,954, with [C-11] methyl iodide and tetrabutylammonium hydroxide in DMF. In vivo studies with [C-11] CP-126,998 in mice show that this radiotracer displays highest uptake in striatum (6.2 %ID/g), a brain region known to be rich in AChE. The (striatum-cerebellum)/cerebellar radioactivity ratio reached a maximum of 4.3 at 30 min postinjection, and this ratio decreased to 2.4 at 120 min. .Radiotracer binding was saturable in vivo by pretreatment with CP-118,954. Pretreatment of mice with diisopropylfluorophosphate (4 mg/kg i.p.), a known AChE inhibitor, significantly inhibited binding in striatum in a dose-dependent manner. Initial results suggest that [C-11] CP-126,998 may prove useful as a marker for the study of AChE in humans via PET.

  6. Molecular characterization of a new alkaline-tolerant xylanase from Humicola insolens Y1.

    PubMed

    Shi, Pengjun; Du, Yanlong; Yang, Hong; Huang, Huoqing; Zhang, Xiu; Wang, Yaru; Yao, Bin

    2015-01-01

    An endo-1,4-β-xylanase-encoding gene, xyn11B, was cloned from the thermophilic fungus Humicola insolens Y1. The gene encodes a multimodular xylanase that consists of a typical hydrophobic signal sequence, a catalytic domain of glycoside hydrolase (GH) family 11, a glycine-rich linker, and a family 1 carbohydrate binding module (CBM1). Deduced Xyn11B shares the highest identity of 74% with a putative xylanase from Podospora anserina S mat+. Recombinant Xyn11B was successfully expressed in Pichia pastoris and purified to electrophoretic homogeneity. Xyn11B had a high specific activity of 382.0 U mg(-1) towards beechwood xylan and showed optimal activity at pH 6.0 and 50°C. Distinct from most reported acidic fungal xylanases, Xyn11B was alkaline-tolerant, retaining 30.7% of the maximal activity at pH 9.0. The K m and V max values for beechwood xylan were 2.2 mg mL(-1) and 462.8 μmol min(-1) mg(-1), respectively. The enzyme exhibited a wider substrate specificity and produced a mixture of xylooligosaccharides. All these favorable enzymatic properties make Xyn11B attractive for potential applications in various industries. PMID:25629035

  7. Trichoderma reesei XYN VI--a novel appendage-dependent eukaryotic glucuronoxylan hydrolase.

    PubMed

    Biely, Peter; Puchart, Vladimír; Stringer, Mary Ann; Mørkeberg Krogh, Kristian B R

    2014-09-01

    Expression of a Trichoderma reesei gene coding for a putative GH30 xylanase in Aspergillus oryzae led to isolation and purification of a novel xylanase exhibiting catalytic properties different from those of the previously characterized GH30 xylanase XYN IV of T. reesei. The novel enzyme, named XYN VI, exhibited catalytic properties similar to appendage-dependent GH30 glucuronoxylanases previously recognized only in bacteria. XYN VI showed high specific activity only on xylans or xylooligosaccharides containing 4-O-methyl-D-glucuronic acid or D-glucuronic acid side substituents. The cleavage of the main chain takes place primarily at the second glycosidic linkage from the branch towards the reducing end of the polysaccharides or aldouronic acids. These catalytic properties resemble bacterial GH30 glucuronoxylanases, although the recognition of the uronic acid side chains by XYN VI is apparently based on interaction of the substrate with other amino acids. Moreover, in contrast to bacterial enzymes, XYN VI is also capable of slower but significant cleavage of unsubstituted parts of xylan and acidic xylooligosaccharides. The data point to a great catalytic diversity of xylanases produced by the most extensively studied cellulolytic fungus. PMID:25041335

  8. Feruloyl esterase from the edible mushroom Panus giganteus: a potential dietary supplement.

    PubMed

    Wang, Li; Ma, Zengqiang; Du, Fang; Wang, Hexiang; Ng, Tzi Bun

    2014-08-01

    A novel 61 kDa feruloyl esterase (FAE) was purified to homogeneity from freshly collected fruiting bodies of Panus giganteus. The isolation procedure involved chromatography on the ion exchangers DEAE-cellulose and Q-Sepharose, followed by size exclusion chromatography on Superdex 75, which produced a purified enzyme with a high specific activity (170.0 U/mg) which was 130-fold higher than that of crude extract. The purified FAE exhibited activity toward synthetic methyl esters and short-chain fatty acid nitrophenyl esters. The Km and Vmax for this enzyme on methyl ferulate were 0.36 mM and 18.97 U/mg proteins, respectively. FAE activity was attained at a maximum at pH 4 and 40 °C, respectively. The FAE activity was inhibited by metal ions to various degrees. The purified FAE could bring about the release of ferulic acid from wheat bran and corn bran under the action of the single purified FAE, and the amount released from wheat bran rose to 51.9% (of the total amount) by the synergistic action of xylanase. PMID:25065258

  9. Characterization of a primary bile ductular cell culture from the livers of rats during extrahepatic cholestasis.

    PubMed Central

    Sirica, A. E.; Sattler, C. A.; Cihla, H. P.

    1985-01-01

    The establishment of novel bile ductular cell cultures was accomplished with the use of explants of a hyperplastic bile ductular tissue preparation obtained from rat livers at 10 to 15 weeks after bile duct ligation or a bile ductular cell fraction isolated from this tissue preparation by a procedure involving Percoll density gradient centrifugation. Observations made on these primary explant and monolayer bile ductular cell cultures were limited to the first 3 days of culture where the morphologic features of the bile ductular epithelium remained fairly well preserved, while fibroblast contamination was found to be very low. These cultured cells also retained over this period a high specific activity for the bile ductular cell marker enzyme gamma-glutamyl transpeptidase, as well as possessed measurable but decreasing specific activities for leucine aminopeptidase and alkaline phosphatase. Karyotypic analysis of the cultured monolayer cells further showed them to be diploid. In addition, preliminary transplantation studies demonstrated the presence of well-differentiated bile ductular-like structures following inoculation of the freshly isolated bile ductular cell fraction into the interscapular fat pads of recipient rats. Images Figure 2 Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 PMID:2861743

  10. Fluorous Analogue of Chloramine-T: Preparation, X-ray Structure Determination, and Use as an Oxidant for Radioiodination and s-Tetrazine Synthesis.

    PubMed

    Dzandzi, James P K; Beckford Vera, Denis R; Genady, Afaf R; Albu, Silvia A; Eltringham-Smith, Louise J; Capretta, Alfredo; Sheffield, William P; Valliant, John F

    2015-07-17

    A fluorous oxidant that can be used to introduce radioiodine into small molecules and proteins and generate iodinated tetrazines for bioorthogonal chemistry has been developed. The oxidant was prepared in 87% overall yield by combining a fluorous amine with tosyl chloride, followed by chlorination using aqueous sodium hypochlorite. A crystal structure of the oxidant, which is a fluorous analogue of chloramine-T, was obtained. The compound was shown to be stable for 7 days in EtOH and for longer than three months as a solid. The oxidant was effective at promoting the labeling of arylstannanes using [(125)I]NaI, where products were isolated in high specific activity in yields ranging from 46% to 86%. Similarly, iodinated biologically active proteins (e.g., thrombin) were successfully produced, as well as a radioiodinated tetrazine, through a concomitant oxidation-halodemetalation reaction. Because of its fluorous nature, unreacted oxidant and associated reaction byproducts can be removed quantitatively from reaction mixtures by passing solutions through fluorous solid phase extraction cartridges. This feature enables rapid and facile purification, which is critical when working with radionuclides and is similarly beneficial for general synthetic applications. PMID:26030355