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Sample records for 111in-labeled cyclic peptide

  1. Gamma scintigraphy imaging of murine invasive pulmonary aspergillosis with a 111In-labeled cyclic peptide

    Introduction: Invasive pulmonary aspergillosis (IPA) is a leading cause of infection-associated death in immunosuppressed patients. Early detection and early administration of antifungal therapy are critical factors in improving outcome for patients with IPA. Here, we evaluated the imaging properties of a 111In-labeled cyclic peptide targeted to Aspergillus fumigatus in an immunosuppressed murine model of IPA. Methods: A cyclic peptide c(CGGRLGPFC)-NH2 was labeled with 111In by means of diethylenetriaminepentaacetic acid (DTPA). Two days after intranasal inoculation of 17.5x106 conidia of A. fumigatus, mice were injected 111In-DTPA-c(CGGRLGPFC)-NH2 intravenously. Biodistribution data were obtained at 2 h, and γ-images were acquired at 10 min and 2 h after radiotracer injection. Healthy mice were used as controls. In addition, a group of infected mice were co-injected with the radiotracer and unlabeled c(CGGRLGPFC)-NH2 to evaluate the inhibition of radiotracer's binding to infected lungs. Autoradiographs of lungs from infected and healthy mice were compared with corresponding photographs of transaxial sections of the lung tissues stained for A. fumigatus hyphae. Results: The labeling efficiency was >98%, with specific radioactivity of up to 74 MBq/nmol peptide. Significantly higher uptake of 111In-DTPA-c(CGGRLGPFC)-NH2 was observed in the lungs of mice infected with A. fumigatus than in those of healthy mice (0.37±0.06 %ID/g vs. 0.14±0.02 %ID/g, P=.00044). Simultaneous injection with unlabeled peptide reduced radioactivity in the infected lungs by 41% (P=.0037). Increased radioactivity in the lungs of infected mice was visible in γ images at both 10 min and 2 h after radiotracer injection. Moreover, autoradiography confirmed radiotracer uptake in infected lungs, but not in the lungs of healthy mice or infected mice co-injected with unlabeled peptide. Conclusions: γ-Imaging with 111In-DTPA-c(CGGRLGPFC)-NH2 clearly delineated experimental IPA in mice. Peptides

  2. Comparison of biological properties of 111In-labeled dimeric cyclic RGD peptides

    Introduction: In this study two 111In-labeled dimeric cyclic RGD peptides, 111In(DOTA-Galacto-RGD2) and 111In(DOTA-3P-RGD2), were evaluated as radiotracers for breast tumor imaging. The objective was to evaluate the impact of SAA, PEG2 and 1,2,3-triazole linkers as compare to PEG4 on the tumor uptake and excretion kinetics of 111In radiotracers. Methods: DOTA-Galacto-RGD2 was prepared by conjugation of Galacto-RGD2 with DOTA-OSu in the presence of diisopropylethylamine. Its integrin αvβ3 binding affinity was determined using a whole-cell displacement assay against 125I-echistatin bound to U87MG glioma cells, and was compared with those of c(RGDfK), DOTA-3P-RGD2 and DOTA-3P-RGK2 (a nonsense peptide conjugate with “scrambled” RGK sequences). 111In(DOTA-Galacto-RGD2) and 111In(DOTA-3P-RGD2) were prepared and evaluated for their tumor-targeting capability and biodistribution properties in athymic nude mice bearing MDA-MB-435 breast tumor xenografts. Planar imaging studies were performed to demonstrate the utility of 111In(DOTA-Galacto-RGD2) and 111In(DOTA-3P-RGD2) for breast tumor imaging. Results: IC50 values of DOTA-Galacto-RGD2, DOTA-3P-RGD2, and DOTA-3P-RGK2 were calculated to be 27 ± 2, 29 ± 4, 596 ± 48 nM, respectively. The tumor uptake values of 111In(DOTA-Galacto-RGD2) (6.79 ± 0.98, 6.56 ± 0.56, 4.17 ± 0.61 and 1.09 ± 0.13 %ID/g at 1, 4, 24 and 72 hours p.i., respectively) were almost identical to those of 111In(DOTA-3P-RGD2) (6.17 ± 1.65, 5.94 ± 0.84, 3.40 ± 0.50 and 0.99 ± 0.20 %ID/g, respectively). 111In(DOTA-Galacto-RGD2) had a faster clearance from blood and muscle than 111In(DOTA-3P-RGD2), leading to higher tumor/blood and tumor/muscle ratios. 111In(DOTA-3P-RGD2) had lower liver uptake and better tumor/liver ratios than 111In(DOTA-Galacto-RGD2). The tumor uptake of 111In(DOTA-Galacto-RGD2) and 111In(DOTA-3P-RGD2) was both integrin αvβ3 and RGD-specific. Imaging data suggest that 111In(DOTA-Galacto-RGD2) and 111In(DOTA-3P-RGD2) are

  3. Gamma scintigraphy imaging of murine invasive pulmonary aspergillosis with a {sup 111}In-labeled cyclic peptide

    Yang Zhi [Department of Experimental Diagnostic Imaging, Infection Control and Employee Health, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Kontoyiannis, Dimitrios P. [Department of Infectious Diseases, Infection Control and Employee Health, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Wen Xiaoxia; Xiong Chiyi; Zhang Rui [Department of Experimental Diagnostic Imaging, Infection Control and Employee Health, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Albert, Nathaniel D. [Department of Infectious Diseases, Infection Control and Employee Health, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Li Chun [Department of Experimental Diagnostic Imaging, Infection Control and Employee Health, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States)], E-mail: cli@mdanderson.org

    2009-04-15

    Introduction: Invasive pulmonary aspergillosis (IPA) is a leading cause of infection-associated death in immunosuppressed patients. Early detection and early administration of antifungal therapy are critical factors in improving outcome for patients with IPA. Here, we evaluated the imaging properties of a {sup 111}In-labeled cyclic peptide targeted to Aspergillus fumigatus in an immunosuppressed murine model of IPA. Methods: A cyclic peptide c(CGGRLGPFC)-NH{sub 2} was labeled with {sup 111}In by means of diethylenetriaminepentaacetic acid (DTPA). Two days after intranasal inoculation of 17.5x10{sup 6} conidia of A. fumigatus, mice were injected {sup 111}In-DTPA-c(CGGRLGPFC)-NH{sub 2} intravenously. Biodistribution data were obtained at 2 h, and {gamma}-images were acquired at 10 min and 2 h after radiotracer injection. Healthy mice were used as controls. In addition, a group of infected mice were co-injected with the radiotracer and unlabeled c(CGGRLGPFC)-NH{sub 2} to evaluate the inhibition of radiotracer's binding to infected lungs. Autoradiographs of lungs from infected and healthy mice were compared with corresponding photographs of transaxial sections of the lung tissues stained for A. fumigatus hyphae. Results: The labeling efficiency was >98%, with specific radioactivity of up to 74 MBq/nmol peptide. Significantly higher uptake of {sup 111}In-DTPA-c(CGGRLGPFC)-NH{sub 2} was observed in the lungs of mice infected with A. fumigatus than in those of healthy mice (0.37{+-}0.06 %ID/g vs. 0.14{+-}0.02 %ID/g, P=.00044). Simultaneous injection with unlabeled peptide reduced radioactivity in the infected lungs by 41% (P=.0037). Increased radioactivity in the lungs of infected mice was visible in {gamma} images at both 10 min and 2 h after radiotracer injection. Moreover, autoradiography confirmed radiotracer uptake in infected lungs, but not in the lungs of healthy mice or infected mice co-injected with unlabeled peptide. Conclusions: {gamma}-Imaging with {sup

  4. Evaluation of 111In-Labeled Cyclic RGD Peptides: Effects of Peptide and Linker Multiplicity on Their Tumor Uptake, Excretion Kinetics and Metabolic Stability

    Jiyun Shi, Yang Zhou, Sudipta Chakraborty, Young-Seung Kim, Bing Jia, Fan Wang, Shuang Liu

    2011-01-01

    Full Text Available Purpose: The purpose of this study was to demonstrate the valence of cyclic RGD peptides, P-RGD (PEG4-c(RGDfK: PEG4 = 15-amino-4,710,13-tetraoxapentadecanoic acid, P-RGD2 (PEG4-E[c(RGDfK]2, 2P-RGD4 (E{PEG4-E[c(RGDfK]2}2, 2P4G-RGD4 (E{PEG4-E[G3-c(RGDfK]2}2: G3 = Gly-Gly-Gly and 6P-RGD4 (E{PEG4-E[PEG4-c(RGDfK]2}2 in binding to integrin αvβ3, and to assess the impact of peptide and linker multiplicity on biodistribution properties, excretion kinetics and metabolic stability of their corresponding 111In radiotracers.Methods: Five new RGD peptide conjugates (DOTA-P-RGD (DOTA =1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid, DOTA-P-RGD2, DOTA-2P-RGD4, DOTA-2P4G-RGD4, DOTA-6P-RGD4, and their 111In complexes were prepared. The integrin αvβ3 binding affinity of cyclic RGD conjugates were determined by a competitive displacement assay against 125I-c(RGDyK bound to U87MG human glioma cells. Biodistribution, planar imaging and metabolism studies were performed in athymic nude mice bearing U87MG human glioma xenografts.Results: The integrin αvβ3 binding affinity of RGD conjugates follows the order of: DOTA-6P-RGD4 (IC50 = 0.3 ± 0.1 nM ~ DOTA-2P4G-RGD4 (IC50 = 0.2 ± 0.1 nM ~ DOTA-2P-RGD4 (IC50 = 0.5 ± 0.1 nM > DOTA-3P-RGD2 (DOTA-PEG4-E[PEG4-c(RGDfK]2: IC50 = 1.5 ± 0.2 nM > DOTA-P-RGD2 (IC50 = 5.0 ± 1.0 nM >> DOTA-P-RGD (IC50 = 44.3 ± 3.5 nM ~ c(RGDfK (IC50 = 49.9 ± 5.5 nM >> DOTA-6P-RGK4 (IC50 = 437 ± 35 nM. The fact that DOTA-6P-RGK4 had much lower integrin αvβ3 binding affinity than DOTA-6P-RGD4 suggests that the binding of DOTA-6P-RGD4 to integrin αvβ3 is RGD-specific. This conclusion is consistent with the lower tumor uptake for 111In(DOTA-6P-RGK4 than that for 111In(DOTA-6P-RGD4. It was also found that the G3 and PEG4 linkers between RGD motifs have a significant impact on the integrin αvβ3-targeting capability, biodistribution characteristics, excretion kinetics and metabolic stability of 111In-labeled cyclic RGD peptides

  5. Evaluation of 111In-Labeled Cyclic RGD Peptides: Effects of Peptide and Linker Multiplicity on Their Tumor Uptake, Excretion Kinetics and Metabolic Stability

    Jiyun Shi, Yang Zhou, Sudipta Chakraborty, Young-Seung Kim, Bing Jia, Fan Wang, Shuang Liu

    2011-01-01

    Purpose: The purpose of this study was to demonstrate the valence of cyclic RGD peptides, P-RGD (PEG4-c(RGDfK): PEG4 = 15-amino-4,710,13-tetraoxapentadecanoic acid), P-RGD2 (PEG4-E[c(RGDfK)]2, 2P-RGD4 (E{PEG4-E[c(RGDfK)]2}2, 2P4G-RGD4 (E{PEG4-E[G3-c(RGDfK)]2}2: G3 = Gly-Gly-Gly) and 6P-RGD4 (E{PEG4-E[PEG4-c(RGDfK)]2}2) in binding to integrin αvβ3, and to assess the impact of peptide and linker multiplicity on biodistribution properties, excretion kinetics and metabolic stability of ...

  6. Evaluation of 111In-Labeled Cyclic RGD Peptides: Effects of Peptide and Linker Multiplicity on Their Tumor Uptake, Excretion Kinetics and Metabolic Stability

    Shi, Jiyun; Zhou, Yang; Chakraborty, Sudipta; Kim, Young-Seung; Jia, Bing; Wang, Fan; LIU, SHUANG

    2011-01-01

    Purpose: The purpose of this study was to demonstrate the valence of cyclic RGD peptides, P-RGD (PEG4-c(RGDfK): PEG4 = 15-amino-4,710,13-tetraoxapentadecanoic acid), P-RGD2 (PEG4-E[c(RGDfK)]2, 2P-RGD4 (E{PEG4-E[c(RGDfK)]2}2, 2P4G-RGD4 (E{PEG4-E[G3-c(RGDfK)]2}2: G3 = Gly-Gly-Gly) and 6P-RGD4 (E{PEG4-E[PEG4-c(RGDfK)]2}2) in binding to integrin αvβ3, and to assess the impact of peptide and linker multiplicity on biodistribution properties, excretion kinetics and metabolic stability of their corr...

  7. Comparative biodistribution of 12 {sup 111}In-labelled gastrin/CCK2 receptor-targeting peptides

    Laverman, Peter; Joosten, Lieke; Eek, Annemarie; Roosenburg, Susan; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Maina, Theodosia [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Maecke, Helmut [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Aloj, Luigi [Fondazione ' ' G. Pascale' ' , Department of Nuclear Medicine, Istituto Nazionale Tumouri, Naples (Italy); Guggenberg, Elisabeth von [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Sosabowski, Jane K. [Queen Mary, University of London, Centre for Molecular Oncology and Imaging, Institute of Cancer, Barts and The London School of Medicine and Dentistry, London (United Kingdom); Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Reubi, Jean-Claude [University of Berne, Institute of Pathology, Berne (Switzerland)

    2011-08-15

    Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed and some have been tested in patients. Here we aimed to compare the in vivo tumour targeting properties of 12 {sup 111}In-labelled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated gastrin/CCK2 receptor-binding peptides. Two CCK8-based peptides and ten gastrin-based peptide analogues were tested. All peptides were conjugated with DOTA and labelled with {sup 111}In. Biodistribution studies were performed in mice with subcutaneous CCK2/gastrin receptor-expressing tumours and with receptor-negative tumours contralaterally. Biodistribution was studied by counting dissected tissues at 1 and 4 h after injection. Both the CCK analogues displayed relatively low tumour uptake (approximately 2.5%ID/g) as compared to minigastrin analogues. Two linear minigastrin peptides (MG0 and sargastrin) displayed moderate tumour uptake at both 1 and 4 h after injection, but also very high kidney uptake (both higher than 48%ID/g). The linear MG11, lacking the penta-Glu sequence, showed lower tumour uptake and also low kidney uptake. Varying the N-terminal Glu residues in the minigastrin analogues led to improved tumour targeting properties, with PP-F11 displaying the optimal biodistribution. Besides the monomeric linear peptides, a cyclized peptide and a divalent peptide were tested. Based on these studies, optimal peptides for peptide receptor radionuclide targeting of CCK2/gastrin receptor-expressing tumours were the linear minigastrin analogue with six D-Glu residues (PP-F11), the divalent analogue MGD5 and the cyclic peptide cyclo-MG1. These peptides combined high tumour uptake with low kidney retention, and may

  8. Effects of linker variation on the in vitro and in vivo characteristics of an 111In-labeled RGD peptide

    Introduction: Due to the selective expression of the αvβ3 integrin in tumors, radiolabeled arginine-glycine-aspartic acid (RGD) peptides are attractive candidates for tumor targeting. Minor modifications of these peptides could have a major impact on in vivo characteristics. In this study, we systematically investigated the effects of linker modification between two cyclic RGD sequences and DOTA (1,4,7,10-tetraazadodecane-N,N',N',N'''-tetraacetic acid) on the in vitro and in vivo characteristics of the tracer. Methods: A dimeric RGD peptide was synthesized and conjugated either directly with DOTA or via different linkers: PEG4 (polyethylene glycol), glutamic acid or lysine. The RGD peptides were radiolabeled with 111In, and their in vitro and in vivo αvβ3-binding characteristics were determined. Results: LogP values varied between -2.82±0.06 and -3.95±0.33. The IC50 values for DOTA-E-[c(RGDfK)]2, DOTA-PEG4-E-[c(RGDfK)]2, DOTA-E-E-[c(RGDfK)]2 and DOTA-K-E-[c(RGDfK)]2 were comparable. Two hours after injection, the tumor uptakes of the 111In-labeled compounds were not significantly different. The kidney accumulation of [111In]-DOTA-K-E-[c(RGDfK)]2 [4.05±0.20% of the injected dose per gram (ID/g)] was significantly higher as compared with that of [111In]-DOTA-E-[c(RGDfK)]2 (2.63±0.19% ID/g; P111In]-DOTA-E-E-[c(RGDfK)]2 (2.16±0.21% ID/g; P111In]-DOTA-E-E-[c(RGDfK)]2 (2.12±0.09% ID/g) was significantly higher as compared with that of [111In]-DOTA-E-[c(RGDfK)]2 (1.64±0.1% ID/g; P111In]-DOTA-K-E-[c(RGDfK)]2 (1.52±0.04% ID/g; Pvβ3 and tumor uptake. Insertion of lysine caused enhanced kidney retention; that of glutamic acid also resulted in enhanced retention in the kidneys. PEG4 appeared to be the most suitable linker as compared with glutamic acid and lysine because it has the highest tumor-to-blood ratio and the lowest uptake in the kidney and liver

  9. Development of 111In-labeled tumor-associated antigen peptides for monitoring dendritic-cell-based vaccination

    Dendritic cells (DC) are professional antigen-presenting cells capable of inducing potent immune responses. In our ongoing clinical trials, human leukocyte antigen (HLA)-A2.1+ melanoma patients are vaccinated with mature DC, presenting tumor-derived peptides in major histocompatibility complexes (MHC) to naive T cells. Previously, we have shown that both intradermally and intranodally injected 111In-labeled mature DC migrate to draining lymph nodes. However, little is known about the fate of the MHC-peptide complex after injection of these peptide-loaded DC. The aim of the present study was to develop radiolabeled, tumor-derived peptides to monitor their binding to MHC Class I. Methods: The HLA-A2.1 binding peptide gp100:154-162mod (gp100:154m) was conjugated with diethylenetriamine pentaacetic acid (DTPA) either at the N-terminus (α-DTPA-gp100:154m) or at the epsilon amino group of the Lys154 residue (ε-DTPA-gp100:154m) and labeled with 111In. Results: The maximum specific activity for both peptides was 13 GBq/μmol. The IC5 of the α-[111In]DTPA-gp100:154m peptide was >75 μM. The IC5 of the 111In-labeled ε-DTPA-gp100:154m was 3 μM, similar to the unconjugated peptide. MHC binding studies showed specific binding of the ε-[111In]DTPA-gp100:154m peptide to the JY cells at 4 deg. C. Interestingly, no specific binding was observed for the α-[111In]DTPA-gp100:154m peptide. In contrast to the α-[111In]DTPA-gp100:154m peptide, the ε-[111In]DTPA-gp100:154m peptide was recognized by cytotoxic T cells. Conclusion: When DTPA was conjugated to the epsilon NH2 group of the Lys154 residue, MHC binding of the peptide was preserved and could still be recognized by cytotoxic T cells. These studies allow the noninvasive determination of the behavior of MHC-peptide complexes on DC in vivo

  10. Development of a {sup 111}In-labeled peptide derivative targeting a chemokine receptor, CXCR4, for imaging tumors

    Hanaoka, Hirofumi [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Graduate School of Medicine, Gunma University, Showa-machi, Maebashi 371-8511 (Japan); Mukai, Takahiro [Graduate School of Medicine, Kyoto University, Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Graduate School of Pharmaceutical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Tamamura, Hirokazu [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda-ku, Tokyo 101-0062 (Japan); Mori, Tomohiko [Graduate School of Medicine, Kyoto University, Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Ishino, Seigo [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Ogawa, Kazuma [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Iida, Yasuhiko [Graduate School of Medicine, Gunma University, Showa-machi, Maebashi 371-8511 (Japan); Doi, Ryuichiro [Graduate School of Medicine, Kyoto University, Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Fujii, Nobutaka [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Saji, Hideo [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan)]. E-mail: hsaji@pharm.kyoto-u.ac.jp

    2006-05-15

    The chemokine receptor CXCR4 is highly expressed in tumor cells and plays an important role in tumor metastasis. The aim of this study was to develop a radiopharmaceutical for the imaging of CXCR4-expressing tumors in vivo. Based on structure-activity relationships, we designed a 14-residue peptidic CXCR4 inhibitor, Ac-TZ14011, as a precursor for radiolabeled peptides. For {sup 111}In-labeling, diethylenetriaminepentaacetic acid (DTPA) was attached to the side chain of D-Lys{sup 8} which is distant from the residues indispensable for the antagonistic activity. In-DTPA-Ac-TZ14011 inhibited the binding of a natural ligand, stromal cell-derived factor-1{alpha}, to CXCR4 in a concentration-dependent manner with an IC{sub 5} of 7.9 nM (Ac-TZ14011: 1.2 nM). In biodistribution experiments, more {sup 111}In-DTPA-Ac-TZ14011 accumulated in the CXCR4-expressing tumor than in blood or muscle. Furthermore, the tumor-to-blood and tumor-to-muscle ratios were significantly reduced by coinjection of Ac-TZ14011, indicating a CXCR4-mediated accumulation in tumor. These findings suggested that {sup 111}In-DTPA-Ac-TZ14011 would be a potential agent for the imaging of CXCR4 expression in metastatic tumors in vivo.

  11. Cellular penetration and nuclear importation properties of 111In-labeled and 123I-labeled HIV-1 tat peptide immunoconjugates in BT-474 human breast cancer cells

    Introduction: Our objective was to compare the cell penetration and nuclear importation properties of 111In-labeled and 123I-labeled immunoconjugates (ICs) composed of 16-mer peptides (GRKKRRQRRRPPQGYG) derived from HIV-1 transactivator of transcription (tat) protein and anti-mouse IgG (mIgG) in BT-474 breast cancer (BC) cells. Methods: [111In]tat ICs were constructed by site-specific conjugation of tat peptides to NaIO4--oxidized carbohydrates in the Fc domain of diethylenetriaminepentaacetic-acid-modified anti-mIgG antibodies. Immunoreactivity against mIgG was assessed in a competition assay. The kinetics of the accumulation of [111In]anti-mIgG-tat IC and [123I]anti-mIgG-tat ICs in BT-474 cells and the elimination of radioactivity from cells, cytoplasm or nuclei were determined. The effects of excess tat peptides or NH4Cl (an inhibitor of endosomal acidification) on cellular uptake and nuclear importation of [111In]anti-mIgG-tat were measured. Results: [111In]anti-mIgG-tat was >97% radiochemically pure and exhibited preserved immunoreactivity with mIgG epitopes. [123I]Anti-mIgG-tat penetrated BT-474 cells more rapidly than [111In]anti-mIgG-tat ICs and achieved a 1.5-fold to a 2-fold higher uptake in cells and nuclei. Cell penetration and nuclear uptake of [111In]anti-mIgG-tat were inhibited by excess tat peptides and NH4Cl. Elimination of radioactivity from BT-474 cells and nuclei was more rapid and complete for 123I-labeled than for 111In-labeled anti-mIgG-tat ICs. Conclusion: Tat peptides derived from HIV-1 tat protein promoted the penetration and nuclear uptake of radioactivity following the incubation of 111In-labeled and 123I-labeled anti-mIgG antibodies with BT-474 human BC cells. 111In-labeled tat ICs are feasible for inserting radionuclides into cancer cells with potential for targeting intracellular and, particularly, nuclear epitopes for imaging and/or radiotherapeutic applications

  12. Metastatic melanoma imaging with an 111In-labeled lactam bridge-cyclized α-melanocyte-stimulating hormone peptide

    Introduction: The purpose of this study was to examine whether a novel lactam bridge-cyclized 111In-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Gly-Glu-c[Lys-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Arg-Pro-Val-Asp] {DOTA-GlyGlu-CycMSH} could be an effective imaging probe for metastatic melanoma detection. Methods: 111In-DOTA-GlyGlu-CycMSH was prepared and purified by reverse-phase high-performance liquid chromatography (RP-HPLC). The internalization and efflux of 111In-DOTA-GlyGlu-CycMSH were examined in B16/F10 melanoma cells. The biodistribution of 111In-DOTA-GlyGlu-CycMSH was determined in B16/F10 pulmonary metastatic melanoma-bearing and normal C57 mice. Pulmonary metastatic melanoma imaging was performed by small-animal single-photon emission computed tomography (SPECT)/CT (Nano-SPECT/CT) using 111In-DOTA-GlyGlu-CycMSH as an imaging probe and compared with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography (PET) imaging. Results: 111In-DOTA-GlyGlu-CycMSH was readily prepared with greater than 95% radiolabeling yield. 111In-DOTA-GlyGlu-CycMSH displayed rapid internalization and extended efflux in B16/F10 cells. 111In-DOTA-GlyGlu-CycMSH exhibited significantly (P111In-DOTA-GlyGlu-CycMSH 2 h post-injection rather than with [18F]FDG 1 h post-injection. Conclusions: 111In-DOTA-GlyGlu-CycMSH exhibited favorable metastatic melanoma-targeting and -imaging properties, highlighting its potential as an effective imaging probe for metastatic melanoma detection.

  13. Metastatic melanoma imaging with an {sup 111}In-labeled lactam bridge-cyclized {alpha}-melanocyte-stimulating hormone peptide

    Guo Haixun; Shenoy, Nalini; Gershman, Benjamin M.; Yang, Jianquan [College of Pharmacy, University of New Mexico, Albuquerque, NM 87131 (United States); Sklar, Larry A. [College of Pharmacy, University of New Mexico, Albuquerque, NM 87131 (United States); Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Department of Pathology, University of New Mexico, Albuquerque, NM 87131 (United States); Miao Yubin [College of Pharmacy, University of New Mexico, Albuquerque, NM 87131 (United States); Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Department of Dermatology, University of New Mexico, Albuquerque, NM 87131 (United States)], E-mail: ymiao@salud.unm.edu

    2009-04-15

    Introduction: The purpose of this study was to examine whether a novel lactam bridge-cyclized {sup 111}In-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Gly-Glu-c[Lys-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Arg-Pro-Val-Asp] {l_brace}DOTA-GlyGlu-CycMSH{r_brace} could be an effective imaging probe for metastatic melanoma detection. Methods: {sup 111}In-DOTA-GlyGlu-CycMSH was prepared and purified by reverse-phase high-performance liquid chromatography (RP-HPLC). The internalization and efflux of {sup 111}In-DOTA-GlyGlu-CycMSH were examined in B16/F10 melanoma cells. The biodistribution of {sup 111}In-DOTA-GlyGlu-CycMSH was determined in B16/F10 pulmonary metastatic melanoma-bearing and normal C57 mice. Pulmonary metastatic melanoma imaging was performed by small-animal single-photon emission computed tomography (SPECT)/CT (Nano-SPECT/CT) using {sup 111}In-DOTA-GlyGlu-CycMSH as an imaging probe and compared with 2-[{sup 18}F]fluoro-2-deoxy-D-glucose ([{sup 18}F]FDG) positron emission tomography (PET) imaging. Results: {sup 111}In-DOTA-GlyGlu-CycMSH was readily prepared with greater than 95% radiolabeling yield. {sup 111}In-DOTA-GlyGlu-CycMSH displayed rapid internalization and extended efflux in B16/F10 cells. {sup 111}In-DOTA-GlyGlu-CycMSH exhibited significantly (P<.05) higher uptakes (2.00{+-}0.74%ID/g at 2 h post-injection and 1.83{+-}0.12%ID/g at 4 h post-injection) in metastatic melanoma-bearing lung than that in normal lung (0.08{+-}0.08%ID/g and 0.05{+-}0.05%ID/g at 2 and 4 h post-injection, respectively). The activity accumulation in normal organs was low (<0.5%ID/g) except for the kidneys 2 and 4 h post-injection. B16/F10 pulmonary melanoma metastases were clearly visualized with {sup 111}In-DOTA-GlyGlu-CycMSH 2 h post-injection rather than with [{sup 18}F]FDG 1 h post-injection. Conclusions: {sup 111}In-DOTA-GlyGlu-CycMSH exhibited favorable metastatic melanoma-targeting and -imaging properties, highlighting its potential as an effective imaging

  14. Effects of linker variation on the in vitro and in vivo characteristics of an 111In-labeled RGD peptide.

    Dijkgraaf, I.; Liu, S.; Kruijtzer, J.A.; Soede, A.C.; Oyen, W.J.G.; Liskamp, R.M.; Corstens, F.H.M.; Boerman, O.C.

    2007-01-01

    INTRODUCTION: Due to the selective expression of the alpha(v)beta3 integrin in tumors, radiolabeled arginine-glycine-aspartic acid (RGD) peptides are attractive candidates for tumor targeting. Minor modifications of these peptides could have a major impact on in vivo characteristics. In this study,

  15. Tumor targeting and SPECT imaging properties of an {sup 111}In-labeled galectin-3 binding peptide in prostate carcinoma

    Deutscher, Susan L. [Department of Biochemistry, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States); Research Division, Harry S. Truman Veterans Hospital, Columbia, MO 65201 (United States); Figueroa, Said D. [Research Division, Harry S. Truman Veterans Hospital, Columbia, MO 65201 (United States); Kumar, Senthil R. [Department of Biochemistry, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States)], E-mail: kumars@missouri.edu

    2009-02-15

    Introduction: Galectin-3 (gal-3) is a carbohydrate binding protein that has been implicated in cell adhesion, tumor invasion and metastasis. The objective of this study was to evaluate the tumor targeting and imaging properties of a gal-3 binding peptide selected by phage display in a mouse model of metastatic human prostate carcinoma expressing gal-3. Methods: A gal-3 binding peptide, ANTPCGPYTHDCPVKR, was synthesized with a Gly-Ser-Gly (GSG) spacer and 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) and then radiolabeled with {sup 111}In. The in vitro cell binding properties of {sup 111}In-DOTA-(GSG)-ANTPCGPYTHDCPVKR were determined in metastatic human PC3-M prostate carcinoma cells. The pharmacokinetics and single-photon emission computed tomographic (SPECT/CT) imaging with the radiolabeled peptide were evaluated in SCID mice bearing human PC3-M prostate carcinoma tumor xenografts. Results: The radiolabeled peptide bound with a 50% inhibitory concentration of 191{+-}10.2 nM to cultured PC3-M prostate carcinoma cells. In vivo tumor uptake and retention coupled with fast whole-body clearance of the peptide were demonstrated in PC3-M tumor-bearing SCID mice. The tumor uptake rates of the radiolabeled peptide were 1.27{+-}0.10%ID/g at 30 min, 0.82{+-}0.15%ID/g at 1 h and 0.57{+-}0.09%ID/g at 2 h. MicroSPECT/CT studies revealed good tumor uptake of {sup 111}In-DOTA-(GSG)-ANTPCGPYTHDCPVKR 2 h postinjection, while uptake in normal organs was low, with the exception of the kidneys. Conclusions: In vitro cell binding along with tumor uptake of {sup 111}In-DOTA-(GSG)-ANTPCGPYTHDCPVKR in PC3-M human prostate carcinoma tumor-bearing SCID mice suggests the potential of this peptide as a radiopharmaceutical for imaging of gal-3-expressing prostate tumors.

  16. 111In-labeled Lactam Bridge-cyclized Alpha-Melanocyte Stimulating Hormone Peptide Analogues for Melanoma Imaging

    Miao, Yubin; Gallazzi, Fabio; Guo, Haixun; Quinn, Thomas P.

    2008-01-01

    The purpose of this study was to examine the influence of the lactam bridge cyclization on melanoma targeting and biodistribution properties of the radiolabeled conjugates. Two novel lactam bridge-cyclized α-MSH peptide analogues, DOTA-CycMSH (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]) and DOTA-GlyGlu-CycMSH (DOTA-Gly-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]), were synthesized and radiolabeled with 111In. The in...

  17. 111In-labeled KCCYSL peptide as an imaging probe for ErbB-2-expressing ovarian carcinomas

    Deutscher, Susan L.; Figueroa, Said D.; Kumar, Senthil R.

    2009-01-01

    Aberrant expression of ErbB-2, a member of the epidermal growth factor family of receptors, has been implicated in the formation of various malignancies including ovarian cancer. The objective of this study was to determine if the bacteriophage (phage) display-selected ErbB-2 targeting peptide, KCCYSL, once radiolabeled with 111In would serve as a tumor targeting and Single Photon Emission Computed Tomography (SPECT/CT) imaging agent in a mouse model of human ovarian carcinoma expressing ErbB...

  18. Evaluation of 111In-Labeled Cyclic RGD Peptides: Tetrameric Not Tetravalent

    Chakraborty, Sudipta; Shi, Jiyun; Kim, Young-Seung; Zhou, Yang; Jia, Bing; Wang, Fan; Liu, Shuang

    2010-01-01

    This report presents the synthesis and evaluation of 111In(DOTA-6G-RGD4) (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid; 6G-RGD4 = E{G3-E[G3-c(RGDfK)]2}2 and G3 = Gly-Gly-Gly), 111In(DOTA-RGD4) (RGD4 = E{E[c(RGDfK)]2}2) and 111In(DOTA-3G-RGD2) (3G-RGD2 = G3-E[G3-c(RGDfK)]2) as new radiotracers for imaging integrin αvβ3–positive tumors. The IC50 values of DOTA-6G-RGD4, DOTA-RGD4 and DOTA-3G-RGD2 were determined to be 0.4 ± 0.1, 1.5 ± 0.2 and 1.3 ± 0.2 nM against 125I-c(RGDyK) ...

  19. Novel targeted nuclear imaging agent for gastric cancer diagnosis: glucose-regulated protein 78 binding peptide-guided 111In-labeled polymeric micelles

    Cheng CC

    2013-04-01

    radioisotope indium-111 (111In was measured and analyzed by instant thin layer chromatography. The coupling efficiency of DTPA-conjugated micelles and DTPA/GRP78BP-conjugated micelles with 111In was 85% and 93%, respectively. For characterization and trace imaging, the radioisotope 111In-targeting tumors were detected and imaged in a xenograft murine model using nano single photon emission computed tomography/computed tomography. The results revealed that the radioactive intensity measured in the animals administered with GRP78BP-guided 111In-labeled micelles was statistically higher than that in animals administered with 111In-labeled micelles, demonstrating that GRP78BP more than doubled the accumulation of micelles to the tumor tissue (P < 0.05. The results indicate that the gastric cancer biomarker GRP78 is a probing target in the application of nuclear imaging for tumor diagnosis. This novel GRP78BP-guided micelle agent may be applied in clinical practice to complement the histological diagnosis.Keywords: biomarker, glucose-regulated protein 78, nuclear imaging, gastric cancer, micelles

  20. 111In-labelled somatostatin analogues in a rat tumour model: somatostatin receptor status and effects of peptide receptor radionuclide therapy

    Peptide receptor scintigraphy with the radioactive somatostatin analogue 111In-DTPA-octreotide is a sensitive and specific technique to show in vivo the presence of somatostatin receptors on various tumours. Since 111In emits not only gamma rays but also therapeutic Auger and internal conversion electrons with a medium to short tissue penetration (0.02-10 μm and 200-550 μm, respectively), 111In-DTPA-octreotide is also being used for peptide receptor radionuclide therapy (PRRT). In this study we investigated the therapeutic effects of 111In-DTPA-octreotide in tumours of various sizes. Regrowth of a tumour despite PRRT with 111In-DTPA-octreotide may be due to the lack of crossfire from 111In, whereby any possible receptor-negative tumour cell can multiply. We therefore also investigated the somatostatin receptor status of the tumour before and after PRRT. The radiotherapeutic effects of different doses of 111In-DTPA-octreotide in vivo were investigated in Lewis rats bearing small (≤1 cm2) or large (≥8 cm2) somatostatin receptor-positive rat pancreatic CA20948 tumours expressing the somatostatin receptor subtype 2 (sst2). In addition, the somatostatin receptor density on the tumour after injection of a therapeutic labelled somatostatin analogue was investigated when the tumour was either declining in size or regrowing after an initial reduction in size. To initiate a partial response of the tumour (so that regrowth would follow) and not a complete response, a relatively low dose was administered. Impressive radiotherapeutic effects of 111In-labelled octreotide were observed in this rat tumour model. Complete responses (up to 50%) were found in the animals bearing small (≤1 cm2) tumours after at least three injections of 111 MBq or a single injection of 370 MBq 111In-DTPA-octreotide, leading to a dose of 6.3-7.8 mGy/MBq (1-10 g tumour). In the rats bearing the larger (≥8 cm2) tumours, the effects were much less pronounced and only partial responses were

  1. Cellular penetration and nuclear importation properties of {sup 111}In-labeled and {sup 123}I-labeled HIV-1 tat peptide immunoconjugates in BT-474 human breast cancer cells

    Cornelissen, Bart [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3M2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Hu, Meiduo [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3M2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); McLarty, Kristin [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3M2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Costantini, Dan [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3M2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Reilly, Raymond M. [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3M2 (Canada) and Department of Medical Imaging, University of Toronto, Toronto, ON, M5S 3M2 (Canada) and Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada) and Toronto General Research Institute, University Health Network, Toronto, ON, M5S 3M2 (Canada)]. E-mail: raymond.reilly@utoronto.ca

    2007-01-15

    Introduction: Our objective was to compare the cell penetration and nuclear importation properties of {sup 111}In-labeled and {sup 123}I-labeled immunoconjugates (ICs) composed of 16-mer peptides (GRKKRRQRRRPPQGYG) derived from HIV-1 transactivator of transcription (tat) protein and anti-mouse IgG (mIgG) in BT-474 breast cancer (BC) cells. Methods: [{sup 111}In]tat ICs were constructed by site-specific conjugation of tat peptides to NaIO{sub 4} {sup -}-oxidized carbohydrates in the Fc domain of diethylenetriaminepentaacetic-acid-modified anti-mIgG antibodies. Immunoreactivity against mIgG was assessed in a competition assay. The kinetics of the accumulation of [{sup 111}In]anti-mIgG-tat IC and [{sup 123}I]anti-mIgG-tat ICs in BT-474 cells and the elimination of radioactivity from cells, cytoplasm or nuclei were determined. The effects of excess tat peptides or NH{sub 4}Cl (an inhibitor of endosomal acidification) on cellular uptake and nuclear importation of [{sup 111}In]anti-mIgG-tat were measured. Results: [{sup 111}In]anti-mIgG-tat was >97% radiochemically pure and exhibited preserved immunoreactivity with mIgG epitopes. [{sup 123}I]Anti-mIgG-tat penetrated BT-474 cells more rapidly than [{sup 111}In]anti-mIgG-tat ICs and achieved a 1.5-fold to a 2-fold higher uptake in cells and nuclei. Cell penetration and nuclear uptake of [{sup 111}In]anti-mIgG-tat were inhibited by excess tat peptides and NH{sub 4}Cl. Elimination of radioactivity from BT-474 cells and nuclei was more rapid and complete for {sup 123}I-labeled than for {sup 111}In-labeled anti-mIgG-tat ICs. Conclusion: Tat peptides derived from HIV-1 tat protein promoted the penetration and nuclear uptake of radioactivity following the incubation of {sup 111}In-labeled and {sup 123}I-labeled anti-mIgG antibodies with BT-474 human BC cells. {sup 111}In-labeled tat ICs are feasible for inserting radionuclides into cancer cells with potential for targeting intracellular and, particularly, nuclear epitopes for

  2. 68Ga- and 111In-labelled DOTA-RGD peptides for imaging of αvβ3 integrin expression

    αvβ3 integrins are important cell adhesion receptors involved in angiogenic processes. Recently, we demonstrated using [18F]Galacto-RGD that monitoring of αvβ3 expression is feasible. Here, we introduce 68Ga- and 111In-labelled derivatives and compare them with [18F]Galacto-RGD. For radiolabelling, cyclo(RGDfK(DOTA)) was synthesised using SPPS. For in vitro characterisation determination of partition coefficients, protein binding, metabolic stability, αvβ3 affinity and cell uptake and for in vivo characterization, biodistribution studies and micro positron emission tomography (PET) imaging were carried out. For in vivo and in vitro studies, human melanoma M21 (αvβ3 positive) and M21-L (αvβ3 negative) cells were used. Both tracers can be synthesised straightforward. The compounds showed hydrophilic properties and high metabolic stability. Up to 23% protein-bound activity for [68Ga]DOTA-RGD and only up to 1.4% for [111In]DOTA-RGD was found. Cell uptake studies indicate receptor-specific accumulation. This is confirmed by the biodistribution data. One hour p.i. accumulation in αvβ3-positive tumours was 2.9 ± 0.3%ID/g and in αvβ3-negative tumours 0.8 ± 0.1%ID/g for [68Ga]DOTA-RGD ([111In]DOTA-RGD: 1.9 ± 0.3%ID/g and 0.5 ± 0.2%ID/g; [18F]Galacto-RGD: 1.6 ± 0.2%ID/g and 0.4 ± 0.1%ID/g). Thus, tumour uptake ratios were comparable. Due to approx. 3-fold higher blood pool activities for [68Ga]DOTA-RGD, tumour/blood ratios were higher for [111In]DOTA-RGD and [18F]Galacto-RGD. However, microPET studies demonstrated that visualisation of αvβ3-positive tumours using [68Ga]DOTA-RGD is possible. Our data indicate that [68Ga]DOTA-RGD allows monitoring of αvβ3 expression. Especially, the much easier radiosynthesis compared to [18F]Galacto-RGD would make it an attractive alternative. However, due to higher blood pool activity, [18F]Galacto-RGD remains superior for imaging αvβ3 expression. Introduction of alternative chelator systems may overcome the

  3. Comparison of the binding and internalization properties of 12 DOTA-coupled and {sup 111}In-labelled CCK2/gastrin receptor binding peptides: a collaborative project under COST Action BM0607

    Aloj, Luigi; Aurilio, Michela; Rinaldi, Valentina; D' Ambrosio, Laura [Istituto Nazionale Tumori, Fondazione ' ' G. Pascale' ' , AF Medicina Nucleare, Naples (Italy); Tesauro, Diego [Universita ' ' Federico II' ' , CIRPeB, Naples (Italy); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Maina, Theodosia [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Mansi, Rosalba [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Guggenberg, Elisabeth von [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Joosten, Lieke [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Institute of Cancer, Barts and the London Queen Mary' s School of Medicine and Dentistry, Centre for Molecular Oncology and Imaging, London (United Kingdom); Breeman, W.A.P.; Blois, Erik de; Koelewijn, Stuart; Melis, Marleen; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Waser, Beatrice; Beetschen, Karin; Reubi, Jean Claude [University of Berne, Berne (Switzerland)

    2011-08-15

    Specific overexpression of cholecystokinin 2 (CCK2)/gastrin receptors has been demonstrated in several tumours of neuroendocrine origin. In some of these cancer types, such as medullary thyroid cancer (MTC), a sensitive diagnostic modality is still unavailable and therapeutic options for inoperable lesions are needed. Peptide receptor radionuclide therapy (PRRT) may be a viable therapeutic strategy in the management of these patients. Several CCK2R-targeted radiopharmaceuticals have been described in recent years. As part of the European Union COST Action BM0607 we studied the in vitro and in vivo characteristics of 12 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated CCK2R binding peptides. In the present study, we analysed binding and internalization characteristics. Stability, biodistribution and imaging studies have been performed in parallel by other centres involved in the project. Determination of IC{sub 50} values was performed using autoradiography, with DOTA-peptides displacing {sup 125}I-CCK from receptors on tissue sections from human tumours. Saturation binding and internalization experiments were performed using {sup 111}In-labelled peptides. The rat AR42J cell line and the human A431-CCK2R transfected cell line were utilized for in vitro experiments; dissociation constants (K{sub d}) and apparent number of binding sites (B{sub max}) were determined. Internalization was determined in receptor-expressing cells by incubating with tracer amounts of peptide at 37 and 4 C for different times up to 120 min. Surface-bound peptide was then stripped either by acid wash or subsequent incubation with 1 {mu}M unlabelled peptide at 4 C. All peptides showed high receptor affinity with IC{sub 50} values ranging from 0.2 to 3.4 nM. Saturation experiments also showed high affinity with K{sub d} values in the 10{sup -9}-10{sup -8} M range. B{sub max} values estimated in A431-CCK2R cells ranged from 0.6 to 2.2 x 10{sup 6} per cell. All peptides

  4. Effect of DOTA Position on Melanoma Targeting and Pharmacokinetic Properties of 111In-labeled Lactam Bridge-Cyclized Alpha-Melanocyte Stimulating Hormone Peptide

    Guo, Haixun; Yang,Jianquan; Gallazzi, Fabio; Prossnitz, Eric R.; Sklar, Larry A.; Miao, Yubin

    2009-01-01

    The purpose of this study was to examine the effect of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) position on melanoma targeting and pharmacokinetics of radiolabeled lactam bridge-cyclized alpha-melanocyte stimulating hormone (α-MSH) peptide.

  5. In Vivo evaluation of an 111In-labeled ST-peptide analog for specific-targeting of human colon cancers

    In vitro competitive binding studies of In-DOTA-NCS-6-Ahx-Phe19-ST[1-19] vs. 125I-Tyr5-6-Ahx-Phe19-ST[1-19] with guanylate cyclase -C (GC-C) receptors on human colon cancer LS-180 cells revealed an IC50 value of 7.7±0.1.6 nM. The in vitro cellular residualization studies of the 111In-DOTA-NCS-ST peptide and GC-C receptor mediated stimulated cGMP production with LS-180 cells demonstrates that this peptide selectively binds to LS-180 cells in an agonistic fashion. In vivo biodistribution studies in LS-180 tumor bearing SCID mice demonstrates that the 111In-DOTA-NCS-ST peptide targets the tumor with a specific uptake of 0.94±0.31%ID/g at 1 hr p.i. and approximately 23% was retained by the tumor at 4 hrs p.i. The radioactivity cleared rapidly from the blood stream with 84.5±3.4%ID at 1h p.i. found in the urine. High activity in urine and kidney, and minimal activity in liver and intestines, demonstrates preferential clearance of the radioactivity through the renal/urinary pathway. The specific in vitro and in vivo accumulation of the radioactivity by LS-180 human colonic cancer cells highlights the potential of radiometallated-DOTA-ST analogs as diagnostic/therapeutic radiopharmaceuticals

  6. Insights into How Cyclic Peptides Switch Conformations.

    McHugh, Sean M; Rogers, Julia R; Yu, Hongtao; Lin, Yu-Shan

    2016-05-10

    Cyclic peptides have recently emerged as promising modulators of protein-protein interactions. However, it is currently highly difficult to predict the structures of cyclic peptides owing to their rugged conformational free energy landscape, which prevents sampling of all thermodynamically relevant conformations. In this article, we first investigate how a relatively flexible cyclic hexapeptide switches conformations. It is found that, although the circular geometry of small cyclic peptides of size 6-8 may require rare, coherent dihedral changes to sample a new conformation, the changes are rather local, involving simultaneous changes of ϕi and ψi or ψi and ϕi+1. The understanding of how these cyclic peptides switch conformations enables the use of metadynamics simulations with reaction coordinates specifically targeting such coupled two-dihedral changes to effectively sample cyclic peptide conformational space. PMID:27031286

  7. Novel pH-Sensitive Cyclic Peptides.

    Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K; Andreev, Oleg A; Parang, Keykavous; Reshetnyak, Yana K

    2016-01-01

    A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582

  8. Modelling water molecules inside cyclic peptide nanotubes

    Tiangtrong, Prangsai; Thamwattana, Ngamta; Baowan, Duangkamon

    2016-03-01

    Cyclic peptide nanotubes occur during the self-assembly process of cyclic peptides. Due to the ease of synthesis and ability to control the properties of outer surface and inner diameter by manipulating the functional side chains and the number of amino acids, cyclic peptide nanotubes have attracted much interest from many research areas. A potential application of peptide nanotubes is their use as artificial transmembrane channels for transporting ions, biomolecules and waters into cells. Here, we use the Lennard-Jones potential and a continuum approach to study the interaction of a water molecule in a cyclo[(- D-Ala- L-Ala)_4-] peptide nanotube. Assuming that each unit of a nanotube comprises an inner and an outer tube and that a water molecule is made up of a sphere of two hydrogen atoms uniformly distributed over its surface and a single oxygen atom at the centre, we determine analytically the interaction energy of the water molecule and the peptide nanotube. Using this energy, we find that, independent of the number of peptide units, the water molecule will be accepted inside the nanotube. Once inside the nanotube, we show that a water molecule prefers to be off-axis, closer to the surface of the inner nanotube. Furthermore, our study of two water molecules inside the peptide nanotube supports the finding that water molecules form an array of a 1-2-1-2 file inside peptide nanotubes. The theoretical study presented here can facilitate thorough understanding of the behaviour of water molecules inside peptide nanotubes for applications, such as artificial transmembrane channels.

  9. Application of Fungal Cyclic Peptides and Metabolites

    Nedvěd, Jan; Šulc, Miroslav; Jegorov, A.; Giannakopulos, A.; Havlíček, Vladimír

    Weinheim : Wiley, 2008 - (Van Eyk, J.; Dunn, M.), s. 483-509 ISBN 978-3-527-31637-3 R&D Projects: GA MŠk LC07017; GA ČR GA203/04/0799 Institutional research plan: CEZ:AV0Z50200510 Keywords : cyclic peptides * mass spectromety * fungal Subject RIV: EE - Microbiology, Virology

  10. Application of Fungal Cyclic Peptides and Metabolites

    Nedvěd, Jan; Šulc, Miroslav; Jegorov, A.; Giannakopulos, A.; Havlíček, Vladimír

    Weinheim : Wiley, 2007 - (Van Eyk, J.; Dunn, M.), s. 483-498 ISBN 978-3-527-31637-3 R&D Projects: GA MŠk LC07017; GA ČR GA203/04/0799 Grant ostatní: XE(XE) EK MTKD-CT-2004-014407 Institutional research plan: CEZ:AV0Z50200510 Source of funding: R - rámcový projekt EK Keywords : cyclic * fungal * peptides Subject RIV: EE - Microbiology, Virology

  11. Targeting of a CCK2 receptor splice variant with 111In-labelled cholecystokinin-8 (CCK8) and 111In-labelled minigastrin

    Radiolabelled cholecystokinin (CCK) and gastrin-derived peptides potentially can be used for peptide receptor radionuclide therapy (PRRT). Recently, a splice variant version of the CCK2R has been identified, designated CCK2i4svR. Constitutive expression of this receptor has been demonstrated in human colorectal cancer and in pancreatic cancer, but not in normal tissue. So far, it has never been shown whether radiolabelled peptides can target the CCK2i4svR in vivo. In this paper, we investigated the potential of sulfated 111In-labelled DOTA-CCK8 (sCCK8), a pan-CCKR-binding peptide, and [111In]DOTA-minigastrin (MG0), a CCK2R selective peptide, for the targeting of the CCK2i4svR. The receptor binding affinity of [111In]DOTA-sCCK8 and [111In]DOTA-MG0 for the CCK2R and CCK2i4svR was determined using stably transfected HEK293 cell lines, expressing either CCK2R or CCK2i4svR. Tumour targeting was studied in HEK293-CCK2i4svR tumour-bearing athymic mice. [111In]DOTA-sCCK8 as well as [111In]DOTA-MG0 specifically bound both CCK2R and CCK2i4svR with affinities in the low nanomolar range. In vivo experiments revealed that accumulation of both peptides in CCK2i4svR-positive tumours was similar (3.21 ± 0.77 and 3.01 ± 0.67%ID/g, sCCK8 and MG0, respectively, 24 h p.i.). Kidney retention of [111In]DOTA-MG0 (32.4 ± 7.5%ID/g, 24 h p.i.) was markedly higher than that of [111In]DOTA-sCCK8 (2.75 ± 0.31%ID/g, 24 h p.i.). We demonstrated that the CCK2i4svR is a potential target for PRRT using a radiolabelled sulfated CCK8 peptide. As this receptor is expressed on colorectal and pancreatic tumours, but not in normal tissue, these tumours are potentially new targets for PRRT with CCK8 and gastrin analogs. (orig.)

  12. Targeting of a CCK{sub 2} receptor splice variant with {sup 111}In-labelled cholecystokinin-8 (CCK8) and {sup 111}In-labelled minigastrin

    Laverman, Peter; Gotthardt, Martin; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Center, Department of Nuclear Medicine, PO Box 9101, HB Nijmegen (Netherlands); Roosenburg, Susan [Radboud University Nijmegen Medical Center, Department of Nuclear Medicine, PO Box 9101, HB Nijmegen (Netherlands); Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen (Netherlands); Park, Jeseong; Hellmich, Mark R. [University of Texas Medical Branch, Department of Surgery and the Sealy Center for Cancer Cell Biology, Galveston, TX (United States); Jong, Marion de [Erasmus Medical Center, Department of Nuclear Medicine, Rotterdam (Netherlands); Rutjes, Floris P.J.T.; Delft, Floris L. van [Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen (Netherlands)

    2008-02-15

    Radiolabelled cholecystokinin (CCK) and gastrin-derived peptides potentially can be used for peptide receptor radionuclide therapy (PRRT). Recently, a splice variant version of the CCK2R has been identified, designated CCK2i4svR. Constitutive expression of this receptor has been demonstrated in human colorectal cancer and in pancreatic cancer, but not in normal tissue. So far, it has never been shown whether radiolabelled peptides can target the CCK2i4svR in vivo. In this paper, we investigated the potential of sulfated {sup 111}In-labelled DOTA-CCK8 (sCCK8), a pan-CCKR-binding peptide, and [{sup 111}In]DOTA-minigastrin (MG0), a CCK2R selective peptide, for the targeting of the CCK2i4svR. The receptor binding affinity of [{sup 111}In]DOTA-sCCK8 and [{sup 111}In]DOTA-MG0 for the CCK2R and CCK2i4svR was determined using stably transfected HEK293 cell lines, expressing either CCK2R or CCK2i4svR. Tumour targeting was studied in HEK293-CCK2i4svR tumour-bearing athymic mice. [{sup 111}In]DOTA-sCCK8 as well as [{sup 111}In]DOTA-MG0 specifically bound both CCK2R and CCK2i4svR with affinities in the low nanomolar range. In vivo experiments revealed that accumulation of both peptides in CCK2i4svR-positive tumours was similar (3.21 {+-} 0.77 and 3.01 {+-} 0.67%ID/g, sCCK8 and MG0, respectively, 24 h p.i.). Kidney retention of [{sup 111}In]DOTA-MG0 (32.4 {+-} 7.5%ID/g, 24 h p.i.) was markedly higher than that of [{sup 111}In]DOTA-sCCK8 (2.75 {+-} 0.31%ID/g, 24 h p.i.). We demonstrated that the CCK2i4svR is a potential target for PRRT using a radiolabelled sulfated CCK8 peptide. As this receptor is expressed on colorectal and pancreatic tumours, but not in normal tissue, these tumours are potentially new targets for PRRT with CCK8 and gastrin analogs. (orig.)

  13. Interpretation of tandem mass spectra obtained from cyclic nonribosomal peptides.

    Liu, Wei-Ting; Ng, Julio; Meluzzi, Dario; Bandeira, Nuno; Gutierrez, Marcelino; Simmons, Thomas L; Schultz, Andrew W; Linington, Roger G; Moore, Bradley S; Gerwick, William H; Pevzner, Pavel A; Dorrestein, Pieter C

    2009-06-01

    Natural and non-natural cyclic peptides are a crucial component in drug discovery programs because of their considerable pharmaceutical properties. Cyclosporin, microcystins, and nodularins are all notable pharmacologically important cyclic peptides. Because these biologically active peptides are often biosynthesized nonribosomally, they often contain nonstandard amino acids, thus increasing the complexity of the resulting tandem mass spectrometry data. In addition, because of the cyclic nature, the fragmentation patterns of many of these peptides showed much higher complexity when compared to related counterparts. Therefore, at the present time it is still difficult to annotate cyclic peptides MS/MS spectra. In this current work, an annotation program was developed for the annotation and characterization of tandem mass spectra obtained from cyclic peptides. This program, which we call MS-CPA is available as a web tool (http://lol.ucsd.edu/ms-cpa_v1/Input.py). Using this program, we have successfully annotated the sequence of representative cyclic peptides, such as seglitide, tyrothricin, desmethoxymajusculamide C, dudawalamide A, and cyclomarins, in a rapid manner and also were able to provide the first-pass structure evidence of a newly discovered natural product based on predicted sequence. This compound is not available in sufficient quantities for structural elucidation by other means such as NMR. In addition to the development of this cyclic annotation program, it was observed that some cyclic peptides fragmented in unexpected ways resulting in the scrambling of sequences. In summary, MS-CPA not only provides a platform for rapid confirmation and annotation of tandem mass spectrometry data obtained with cyclic peptides but also enables quantitative analysis of the ion intensities. This program facilitates cyclic peptide analysis, sequencing, and also acts as a useful tool to investigate the uncommon fragmentation phenomena of cyclic peptides and aids the

  14. 111In-labelled platelets in the diagnosis of kidney transplant rejection

    Granulocytes show a slight increased accumulation during a florid kidney graft rejection. These results do not sustain the preliminary results of Frick that these cells might be a useful tool in the diagnosis of graft rejection. Therefore it was decided to proceed the study using autologous 111In-labelled thrombocytes. The results of this are reported in this paper. (Auth.)

  15. sup 111 In-labeled nonspecific immunoglobulin scanning in the detection of focal infection

    Rubin, R.H.; Fischman, A.J.; Callahan, R.J.; Khaw, B.A.; Keech, F.; Ahmad, M.; Wilkinson, R.; Strauss, H.W. (Massachusetts General Hospital, Boston (USA))

    1989-10-05

    We performed radionuclide scanning after the intravenous injection of human IgG labeled with indium-111 in 128 patients with suspected focal sites of inflammation. Localization of 111In-labeled IgG correlated with clinical findings in 51 infected patients (21 with abdominal or pelvic infections, 11 with intravascular infections, 7 with pulmonary infections, and 12 with skeletal infections). Infecting organisms included gram-positive bacteria, gram-negative bacteria, Pneumocystis carinii, Mycoplasma pneumoniae, and Candida albicans. No focal localization of 111In-labeled IgG was observed in 63 patients without infection. There were five false negative results, and nine results were unusable. Serial scans were carried out in eight patients: continued localization correctly predicted relapse in six, and the absence of localization indicated resolution in two. To determine whether 111In-labeled IgG localization was specific for inflammation, we studied 16 patients with cancer. Focal localization occurred in 13 of these patients (5 with melanomas, 5 with gynecologic cancers, and 1 each with lymphoma, prostate cancer, and malignant fibrous histiocytoma). No localization was seen in patients with renal or colon cancer or metastatic medullary carcinoma of the thyroid. We conclude that 111In-labeled IgG imaging is effective for the detection of focal infection and that serial scans may be useful in assessing therapeutic efficacy. This technique may also be helpful in the evaluation of certain cancers.

  16. 111In-labeled nonspecific immunoglobulin scanning in the detection of focal infection

    We performed radionuclide scanning after the intravenous injection of human IgG labeled with indium-111 in 128 patients with suspected focal sites of inflammation. Localization of 111In-labeled IgG correlated with clinical findings in 51 infected patients (21 with abdominal or pelvic infections, 11 with intravascular infections, 7 with pulmonary infections, and 12 with skeletal infections). Infecting organisms included gram-positive bacteria, gram-negative bacteria, Pneumocystis carinii, Mycoplasma pneumoniae, and Candida albicans. No focal localization of 111In-labeled IgG was observed in 63 patients without infection. There were five false negative results, and nine results were unusable. Serial scans were carried out in eight patients: continued localization correctly predicted relapse in six, and the absence of localization indicated resolution in two. To determine whether 111In-labeled IgG localization was specific for inflammation, we studied 16 patients with cancer. Focal localization occurred in 13 of these patients (5 with melanomas, 5 with gynecologic cancers, and 1 each with lymphoma, prostate cancer, and malignant fibrous histiocytoma). No localization was seen in patients with renal or colon cancer or metastatic medullary carcinoma of the thyroid. We conclude that 111In-labeled IgG imaging is effective for the detection of focal infection and that serial scans may be useful in assessing therapeutic efficacy. This technique may also be helpful in the evaluation of certain cancers

  17. A New Cyclic Peptide from Schnabelia tetradonta

    Hui DOU; Yan ZHOU; Shu lin PENG; Li Sheng DING

    2003-01-01

    A new cyclic octapeptide (schnabepeptide B) was isolated from the aerial part ofSchnabelia tetradonta (Sun) C. Y. Wu et C. Chen (Lamiaceae). Its structure was elucidated ascyclo-(NH-Trp-Gly1-Leu1-Gly2-Pro1-Pro2-Leu2-Pro3-CO) on the basis of extensive 2D NMR andMS spectra.

  18. Development of novel cyclic peptides as pro-apoptotic agents.

    Brindisi, Margherita; Maramai, Samuele; Brogi, Simone; Fanigliulo, Emanuela; Butini, Stefania; Guarino, Egeria; Casagni, Alice; Lamponi, Stefania; Bonechi, Claudia; Nathwani, Seema M; Finetti, Federica; Ragonese, Francesco; Arcidiacono, Paola; Campiglia, Pietro; Valenti, Salvatore; Novellino, Ettore; Spaccapelo, Roberta; Morbidelli, Lucia; Zisterer, Daniela M; Williams, Clive D; Donati, Alessandro; Baldari, Cosima; Campiani, Giuseppe; Ulivieri, Cristina; Gemma, Sandra

    2016-07-19

    Our recent finding that paclitaxel behaves as a peptidomimetic of the endogenous protein Nur77 inspired the design of two peptides (PEP1 and PEP2) reproducing the effects of paclitaxel on Bcl-2 and tubulin, proving the peptidomimetic nature of paclitaxel. Starting from these peptide-hits, we herein describe the synthesis and the biological investigation of linear and cyclic peptides structurally related to PEP2. While linear peptides (2a,b, 3a,b, 4, 6a-f) were found inactive in cell-based assays, biological analysis revealed a pro-apoptotic effect for most of the cyclic peptides (5a-g). Cellular permeability of 5a (and also of 2a,b) on HL60 cells was assessed through confocal microscopy analysis. Further cellular studies on a panel of leukemic cell lines (HL60, Jurkat, MEC, EBVB) and solid tumor cell lines (breast cancer MCF-7 cells, human melanoma A375 and 501Mel cells, and murine melanoma B16F1 cells) confirmed the pro-apoptotic effect of the cyclic peptides. Cell cycle analysis revealed that treatment with 5a, 5c, 5d or 5f resulted in an increase in the number of cells in the sub-G0/G1 peak. Direct interaction with tubulin (turbidimetric assay) and with microtubules (immunostaining experiments) was assessed in vitro for the most promising compounds. PMID:27150036

  19. A cyclic peptidic serine protease inhibitor

    Zhao, Baoyu; Xu, Peng; Jiang, Longguang;

    2014-01-01

    pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending on......, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and...

  20. Mechanism of action of cyclic antimicrobial peptides

    Díaz i Cirac, Anna

    2011-01-01

    This PhD thesis is the result of the combination of experimental and computational techniques with the aim of understanding the mechanism of action of de novo cyclic decapeptides with high antimicrobial activity. By experimental techniques the influence of the replacement of the phenylalanine for tryptophan residue in their antimicrobial activity was tested and the stability in human serum was also analyzed, in order to evaluate their potential therapeutic application as antitumor agents. ...

  1. Evaluation of {sup 111}In labeled antibodies for SPECT imaging of mesothelin expressing tumors

    Misri, Ripen; Saatchi, Katayoun [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Ng, Sylvia S.W. [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Advanced Therapeutics, British Columbia Cancer Agency, Vancouver BC V5Z 1G1 (Canada); Kumar, Ujendra [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Haefeli, Urs O., E-mail: uhafeli@interchange.ubc.ca [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada)

    2011-08-15

    Introduction: Mesothelin is expressed in many cancers, especially in mesothelioma and lung, pancreatic and ovarian cancers. In the present study, we evaluate {sup 111}In labeled antimesothelin antibodies as an imaging bioprobe for the SPECT imaging of mesothelin-expressing tumors. Methods: We radiolabeled the antimesothelin antibodies mAbMB and mAbK1 with {sup 111}In using the p-SCN-bn-DTPA chelator. The immunoreactivity, affinity (K{sub d}) and internalization properties of the resulting two {sup 111}In labeled antibodies were evaluated in vitro using mesothelin-expressing A431K5 cells. The biodistribution and microSPECT/CT imaging studies with {sup 111}In labeled antibodies were performed in mice bearing both mesothelin positive (A431K5) and mesothelin negative (A431) tumors. Results: In vitro studies demonstrated that {sup 111}In-mAbMB bound with a higher affinity (K{sub d}=3.6{+-}1.7 nM) to the mesothelin-expressing A431K5 cells than did the {sup 111}In-mAbK1 (K{sub d}=29.3{+-}2.3 nM). {sup 111}In-mAbMB was also internalized at a greater rate and extent into the A431K5 cells than was the {sup 111}In-mAbK1. Biodistribution studies showed that {sup 111}In-mAbMB was preferentially localized in A431K5 tumors when compared to A431 tumors. At the low dose, the peak A431K5 tumor uptake of 9.65{+-}2.65% ID/g (injected dose per gram) occurred at 48 h, while at high dose tumor uptake peaked with 14.29{+-}6.18% ID/g at 72 h. Non-specific localization of {sup 111}In-mAbMB was mainly observed in spleen.{sup 111}In-mAbK1 also showed superior localization in A431K5 tumors than in A431 tumors, but the peak uptake was only 3.04{+-}0.68% ID/g at 24 h. MicroSPECT/CT studies confirmed better visualization of A431K5 tumors with {sup 111}In-mAbMB, than with {sup 111}In-mAbK1. Conclusion: SPECT imaging of mesothelin expressing tumors was demonstrated successfully. Our findings indicate that the antimesothelin antibody mAbMB has the potential to be developed into a diagnostic agent

  2. Radiopharmaceutical management of 90Y/111In labeled antibodies. Shielding and quatification during preparation and administration

    The combined application of potent β-emitting isotopes for therapy with γ-emitting isotopes for scintigraphy requires a profound regimen concerning team member safety and radionuclide quantification. We have developed materials and methods for a proper and easy manipulation of 90Y during preparation and administration of 90Y/111In pharmaceuticals used for radioimmunotherapy. The efficacy of the shielding measures is documented. Protocols for the calibration of γ-dose calibrators with respect to 90Y are extended to the assessment of quench-corrected liquid scintillation counting of 90Y. The contribution of 90Y backscatter to 111In counting is quantified. Newly developed shielding equipment allows an adequate administration of relatively large volumes (100 ml) of 90Y/111In labeled pharmaceuticals to patients. The procedures described combine pharmaceutical (Good Manufacturing Practice) and radiation safety requirements with an accurate logging of relevant data. (author)

  3. Targeting of gelatinase activity with a radiolabeled cyclic HWGF peptide

    Matrix metalloproteinases (MMPs) are a family of proteinases that play an important role in cancer as well as in numerous diseases. In this article, we describe the labeling of a phage display selected cyclic decapeptide containing the HWGF (histidine-tryptophane-glycine-phenylalanine) sequence to target MMP-2 and MMP-9. To evaluate the ability of this labeled peptide to monitor non invasively MMP-2 and MMP-9 activity, in vitro studies, biodistribution, competition studies and plasma metabolites analyses in Lewis Lung cancer tumor bearing mice were performed

  4. New Cyclic Cystine Bridged Peptides from the Sponge Suberites waedoensis

    Jinhaeng Song

    2014-05-01

    Full Text Available Two new peptides, chujamides A (1 and B (2, were isolated from the marine sponge Suberites waedoensis, which was collected from Korean waters. Based upon the results of the combined spectroscopic analyses, the structures of these compounds were determined to be proline-riched and cyclic cystine bridged dodeca- and undecapeptides. The absolute configurations of all amino acid residues were determined to be l by advanced Marfey’s analysis. The new compounds exhibited weak cytotoxicities against A549 and K562 cell-lines, and compound 2 also demonstrated moderate inhibitory activity against Na+/K+-ATPase.

  5. Ecotoxicologically relevant cyclic peptides from cyanobacterial bloom (Planktothrix rubecens) - a threat to human and environmental health

    Eleršek, Tina; Grach-Pogrebinsky, Olga; Sedmak, Bojan; Carmeli, Shmuel; Lah Turnšek, Tamara; Sever, Nataša

    2015-01-01

    Background. The information of the overall production of major cyanobacterial cyclic peptides in a water body is essential for risk assessment and for the prediction of future development of the bloom. A procedure that gives a reviewof both toxic and non-hepatotoxic hydrophilic cyclic peptide production is important to evaluate the ecological conditions in the water environment and to predict the release of dangerous toxic and tumour promoting substances.Methods. The cyclic peptides were iden...

  6. Comparative biodistribution of 12 111In-labelled gastrin/CCK2 receptor-targeting peptides

    P. Laverman (Peter); L. Joosten; A. Eek (Annemarie); S. Roosenburg (Susan); P.K. Peitl; T. Maina (Theodosia); H. Mäcke (Helmut); L. Aloj (Luigi); E. von Guggenber (Elisabeth); J.K. Sosabowski (Jane); M. de Jong (Marion); J.-C. Reubi (Jean-Claude); W.J.G. Oyen (Wim); O.C. Boerman (Otto)

    2011-01-01

    textabstractPurpose Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy

  7. Simulation-based Discovery of Cyclic Peptide Nanotubes

    Ruiz Pestana, Luis A.

    Today, there is a growing need for environmentally friendly synthetic membranes with selective transport capabilities to address some of society's most pressing issues, such as carbon dioxide pollution, or access to clean water. While conventional membranes cannot stand up to the challenge, thin nanocomposite membranes, where vertically aligned subnanometer pores (e.g. nanotubes) are embedded in a thin polymeric film, promise to overcome some of the current limitations, namely, achieving a monodisperse distribution of subnanometer size pores, vertical pore alignment across the membrane thickness, and tunability of the pore surface chemistry. Self-assembled cyclic peptide nanotubes (CPNs), are particularly promising as selective nanopores because the pore size can be controlled at the subnanometer level, exhibit high chemical design flexibility, and display remarkable mechanical stability. In addition, when conjugated with polymer chains, the cyclic peptides can co-assemble in block copolymer domains to form nanoporous thin films. CPNs are thus well positioned to tackle persistent challenges in molecular separation applications. However, our poor understanding of the physics underlying their remarkable properties prevents the rational design and implementation of CPNs in technologically relevant membranes. In this dissertation, we use a simulation-based approach, in particular molecular dynamics (MD) simulations, to investigate the critical knowledge gaps hindering the implementation of CPNs. Computational mechanical tests show that, despite the weak nature of the stabilizing hydrogen bonds and the small cross section, CPNs display a Young's modulus of approximately 20 GPa and a maximum strength of around 1 GPa, placing them among the strongest proteinaceous materials known. Simulations of the self-assembly process reveal that CPNs grow by self-similar coarsening, contrary to other low-dimensional peptide systems, such as amyloids, that are believed to grow through

  8. PEG modification on 111In-labeled phosphatidyl serine liposomes for imaging of atherosclerotic plaques

    Introduction: Previously, we reported a probe for imaging of atherosclerotic plaques: 111In-labeled liposomes. Liposomes were modified with phosphatidylserine (PS) because macrophages recognize PS and phagocytize apoptotic cells in plaques. PS modification was successful and we could visualize atherosclerotic plaques by single-photon emission computed tomography (SPECT). However, too-rapid blood clearance reduced accumulation of PS-liposomes in plaques in vivo. Therefore, in the present study, PS-liposomes were modified with polyethylene glycol (PEG) to retard the rate of blood clearance. Methods: PS-liposomes (size, 100 nm or 200 nm) were PEGylated with PEG2000 or PEG5000 at 1 or 5 mol%, and radiolabeled with 111In. For the study of uptake in vitro, liposomes were incubated with mouse peritoneal macrophages. Biodistribution studies in vivo were carried out in ddY mice. En face autoradiograms were obtained with apoE−/− mice upon intravenous injection of 111In-liposomes. Results: Uptake was decreased significantly at 5 mol% PEGylation in 100-nm PS-liposomes (*P < 0.05 vs. 0 mol%). All the PEGylated liposomes tested showed significantly lower uptake than the non-PEGylated control in 200-nm liposomes. In vivo results showed slower blood clearance in PEGylated liposomes. Autoradiograms in apoE−/− mice were well matched with Oil Red O staining. Additionally, 200-nm PS-liposomes modified with 5%PEG2000 ([111In]5%PEG2000PS200) showed the highest uptake to the region in vivo. Conclusions: As expected, PEGylation retarded the rate of blood clearance. In addition, it affected liposome uptake by macrophages in vitro. These results suggest that the balance between the rate of blood clearance and macrophage recognition is important, and [111In]5%PEG2000PS200 showed the best results in our investigation

  9. Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation.

    Qvit, Nir; Kornfeld, Opher S

    2016-01-01

    Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency. Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position. We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites' viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a

  10. Human breast tumor imaging using 111In labeled monoclonal antibody: Anthymic mouse model

    The monoclonal antibody (MoAb) 323/A3, an IgG1, was raised against the human breast tumor cell line MCF-7 and recognized a 43 Kd membrane associated glycoprotein. Histochemical studies with the antibody detected 75% of metastatic lymph nodes, 59% of primary breast tumors, and showed some staining in 20% of benign breast lesions. For radionuclide imaging, the MoAb 323/A3 was labeled with both 125I and 111In, via covalently coupled diethylenetriaminepentaacetic acid (DTPA) by the mixed anhydride method. The antibody activity of the DTPA modified 323/A3 was assessed by an immunoassay using viable and fixed MCF-7 target cells. Male athymic nude mice bearing BT-20 human mammary tumors were injected with dual 125I/111In labeled DTPA 323/A3 via the tail veins. The animals were imaged with a gamma camera equipped with a pinhole collimator at 1-3 h, 1, 2, 3, 4 and 5 days after the tracer administration. On day 5 or 6, the animals were killed, and the biodistribution of the radiotracers was determined for the blood, thyroid, heart, lungs, liver, spleen, kidneys, gastro-intestinal tract and tumor. Target to blood ratio at 6 days for the 111In tracer was 24:1 in the group with a mean tumor weight of 0.492 g, and 13:1 in another group with a mean tumor weight of 0.1906 g (day 5). However, the 125I activity showed only 3.6:1 and 5.4:1 target to blood ratios in the corresponding groups. The larger tumors localized less 111I tracer (27.13%±7.57% injected dose/g, Mean±SD) than the smaller tumors (52.75%±22.25% ID/g). Analysis of the gamma images showed that the maximum tracer concentration occurred in the tumors at about 2 to 3 days after intravenous tracer administration. The excellent tumor resolution observed with BT-20 tumors may be due to increased 43 Kd glycoprotein antigen density in this tumor cell line. (orig.)

  11. Evaluation of 111In-labeled macrocyclic chelator-amino acid derivatives for cancer imaging

    Purpose: We evaluated new 111In-labeled amino acid derivatives, in which the amino acids are conjugated with1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) or 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A). Methods: DOTA-aminoalanine (DOTA-A), DOTA-aminohomoalanine (DOTA-H), DOTA-lysine (DOTA-L), DO2A-alanine (DO2A-A), DO3A-alanine (DO3A-A) and DO3A-homoalanine (DO3A-H) were labeled with 111In. In vitro cell uptake assays were performed usingHep3B (a human hepatoma cell line), CT26 (a mouse colon cancer cell line) and U87MG (a human glioma cell line). In vitro cell uptake inhibition assays were performed using U87MG and 111In-DO3A-H. U87MG bearing xenografted mice were subject to biodistribution, SPECT imaging, autoradiography, and immunohistochemistry studies. Results: Of the amino acid derivatives and cell lines examined, U87MG and 111In-DO3A-H showed highest uptake in vitro. This uptake was blocked by 2-aminobicyclo-[2,2,1] heptane-2-carboxylic acid (BCH) and by tryptophan. 111In-DO3A-HSPECT imaging of U87MG bearing xenografted mice visualized tumors (mean tumor-to-muscle ratio 3.16±0.74). Autoradiography and immunohistochemistry revealed that 111In-DO3A-H uptake matched L-type amino acid transporter 1 expression. Conclusion: Tumor uptake was successfully imaged using 111In-DO3A-H in U87MG bearing xenografted mice. 111In-DO3A-H appears to be useful for imaging tumors expressing L-type amino acid transporter.

  12. Cyclic Sulfamidate Enabled Syntheses of Amino Acids, Peptides, Carbohydrates, and Natural Products

    This article reviews the emergence of cyclic sulfamidates as versatile intermediatesfor the synthesis of unnatural amino acids, chalcogen peptides, modified sugars, drugs and drug candidates, and important natural products.

  13. Exploitation of the Ornithine Effect Enhances Characterization of Stapled and Cyclic Peptides

    Crittenden, Christopher M.; Parker, W. Ryan; Jenner, Zachary B.; Bruns, Kerry A.; Akin, Lucas D.; McGee, William M.; Ciccimaro, Eugene; Brodbelt, Jennifer S.

    2016-02-01

    A method to facilitate the characterization of stapled or cyclic peptides is reported via an arginine-selective derivatization strategy coupled with MS/MS analysis. Arginine residues are converted to ornithine residues through a deguanidination reaction that installs a highly selectively cleavable site in peptides. Upon activation by CID or UVPD, the ornithine residue cyclizes to promote cleavage of the adjacent amide bond. This Arg-specific process offers a unique strategy for site-selective ring opening of stapled and cyclic peptides. Upon activation of each derivatized peptide, site-specific backbone cleavage at the ornithine residue results in two complementary products: the lactam ring-containing portion of the peptide and the amine-containing portion. The deguanidination process not only provides a specific marker site that initiates fragmentation of the peptide but also offers a means to unlock the staple and differentiate isobaric stapled peptides.

  14. Pharmacokinetic analysis of 111 in-labeled liposomal Doxorubicin in murine glioblastoma after blood-brain barrier disruption by focused ultrasound.

    Feng-Yi Yang

    Full Text Available The goal of this study was to evaluate the pharmacokinetics of targeted and untargeted (111In-doxorubicin liposomes after these have been intravenously administrated to tumor-bearing mice in the presence of blood-brain barrier disruption (BBB-D induced by focused ultrasound (FUS. An intracranial brain tumor model in NOD-scid mice using human brain glioblastoma multiforme (GBM 8401 cells was developed in this study. (111In-labeled human atherosclerotic plaque-specific peptide-1 (AP-1-conjugated liposomes containing doxorubicin (Lipo-Dox; AP-1 Lipo-Dox were used as a microSPECT probe for radioactivity measurements in the GBM-bearing mice. Compared to the control tumors treated with an injection of (111In-AP-1 Lipo-Dox or (111In-Lipo-Dox, the animals receiving the drugs followed by FUS exhibited enhanced accumulation of the drug in the brain tumors (p<0.05. Combining sonication with drugs significantly increased the tumor-to-normal brain doxorubicin ratio of the target tumors compared to the control tumors. The tumor-to-normal brain ratio was highest after the injection of (111In-AP-1 Lipo-Dox with sonication. The (111In-liposomes micro-SPECT/CT should be able to provide important information about the optimum therapeutic window for the chemotherapy of brain tumors using sonication.

  15. In vivo tracking of {sup 111}In-labeled bone marrow mesenchymal stem cells in acute brain trauma model

    Yoon, Joon-Kee [Department of Nuclear Medicine and Molecular Imaging, Ajou University School of Medicine, Suwon (Korea, Republic of); Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon (Korea, Republic of); Park, Bok-Nam [Department of Nuclear Medicine and Molecular Imaging, Ajou University School of Medicine, Suwon (Korea, Republic of); Shim, Woo-Young [Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon (Korea, Republic of); Department of Molecular Science and Technology, Ajou University, Suwon (Korea, Republic of); Shin, Jin Young [Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon (Korea, Republic of); Department of Neurosurgery, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, Gwang [Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon (Korea, Republic of); Department of Molecular Science and Technology, Ajou University, Suwon (Korea, Republic of); Brain Disease Research Center, Ajou University School of Medicine, Suwon (Korea, Republic of); Ahn, Young Hwan [Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon (Korea, Republic of); Department of Neurosurgery, Ajou University School of Medicine, Suwon (Korea, Republic of)], E-mail: yhahn@ajou.ac.kr

    2010-04-15

    Introduction: This study was to evaluate the in vivo distribution of intravenously transplanted bone marrow-derived mesenchymal stem cells (BMSCs) in an acute brain trauma model by {sup 111}In-tropolone labeling. Methods: Rat BMSCs were labeled with 37 MBq {sup 111}In-tropolone. Their labeling efficiency and in vitro retention rate were measured. The viability and proliferation of labeled BMSCs were evaluated for 14 days after labeling. The biodistribution of {sup 111}In-labeled BMSCs in trauma models was compared with those of sham-operated rats and normal rats on gamma camera images. The migration of {sup 111}In-BMSCs to the traumatic brain was evaluated using confocal microscope. Results: The labeling efficiency of {sup 111}In-BMSCs was 66{+-}5%, and their retention rate was 85.3% at 1 h after labeling. There was no difference in the number of viable cells between {sup 111}In-BMSCs and controls at 48 h after labeling. However, the proliferation of {sup 111}In-BMSCs was inhibited after the third day of labeling, and it did not reach confluency. On gamma camera images, most of the {sup 111}In-BMSCs uptake was observed in the liver and spleen at the second day of injection. The brain uptake of {sup 111}In-BMSCs was detected prominently in trauma models (1.4%) than in sham-operated (0.5%) or normal rats (0.3%). Radiolabeled BMSCs were observed at the traumatic brain on the confocal microscope as they have a homing capacity, although its proliferation capacity was suppressed. Conclusion: Although growth inhibition by {sup 111}In-labeling need to be evaluated further prior to use in humans, {sup 111}In-labeled BMSCs are useful for the tracking of intravenously transplanted mesenchymal stem cells in brain disease models.

  16. Multimodality Molecular Imaging of [18F]-Fluorinated Carboplatin Derivative Encapsulated in [111In]-Labeled Liposomes

    Lamichhane, Narottam

    -(5-fluoro-pentyl)-2-methyl malonic acid as the labeling agent to coordinate with the cisplatin aqua complex. It was then used to treat various cell lines and compared with cisplatin and carboplatin at different concentrations ranging from 0.001 microM to 100 microM for 72 hrs and 96 hrs. IC50 values calculated from cell viability indicated that 19F-FCP is a more potent drug than Carboplatin. Manual radiosynthesis and characterization of [18F]-FCP was performed using [18F]-2-(5-fluoro-pentyl)-2-methyl malonic acid with coordination with cisplatin aqua complex. Automated radiosynthesis of [18F]-FCP was optimized using the manual synthetic procedures and using them as macros for the radiosynthesizer. [18F]-FCP was evaluated in vivo with detailed biodistribution studies and PET imaging in normal and KB 3-1 and KB 8-5 tumor xenograft bearing nude mice. The biodistribution studies and PET imaging of [18F]-FCP showed major uptake in kidneys which attributes to the renal clearance of radiotracer. In vivo plasma and urine stability demonstrated intact [18F]-FCP. [ 111In]-Labeled Liposomes was synthesized and physiochemical properties were assessed with DLS. [111In]-Labeled Liposome was evaluated in vivo with detailed pharmacokinetic studies and SPECT imaging. The biodistribution and ROI analysis from SPECT imaging showed the spleen and liver uptake of [111In]-Labeled Liposome and subsequent clearance of activity with time. [18F]-FCP encapsulated [111In]-Labeled Liposome was developed and physiochemical properties were characterized with DLS. [18F]-FCP encapsulated [111In]-Labeled Liposome was used for in vivo dual tracer PET and SPECT imaging from the same nanoconstruct in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice. PET imaging of [18F]-FCP in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice was performed. Naked [18F]-FCP and [18F]-FCP encapsulated [ 111In]-Labeled Liposome showed different pharmacokinetic profiles. PET

  17. The Molecular Basis for Antimicrobial Activity of Pore-Forming Cyclic Peptides

    Cirac, Anna D.; Moiset, Gemma; Mika, Jacek T.; Kocer, Armagan; Salvador, Pedro; Poolman, Bert; Marrink, Siewert J.; Sengupta, Durba

    2011-01-01

    The mechanism of action of antimicrobial peptides is, to our knowledge, still poorly understood. To probe the biophysical characteristics that confer activity, we present here a molecular-dynamics and biophysical study of a cyclic antimicrobial peptide and its inactive linear analog. In the simulati

  18. Structures of Pahayokolides A and B, Two Cyclic Peptides from a Lyngbya sp

    An, Tianying; Kumar, Thallapuranam Krishnaswamy Suresh; Wang, Minglei; Liu, Li; Lay, Jackson O.; Liyanage, Rohana; Berry, John; Gantar, Miroslav; Marks, Vered; Gawley, Robert E.; Rein, Kathleen S.

    2007-01-01

    The isolation and structure elucidation of two cyclic peptides, pahayokolides A (1) and B (2), is described. Structural features determined for these compounds include a pendant N-acetyl-N-methyl leucine, both E- and Z-dehydrobutyrines, a homophenylalanine, and an unusual polyhydroxy amino acid that is most likely of mixed polyketide synthase/nonribosomal peptide synthase origin. These peptides were purified from a new species of cyanobacteria of the genus Lyngbya, which was isolated from a p...

  19. Synchrotron X-ray fluorescence studies of a bromine-labelled cyclic RGD peptide interacting with individual tumor cells

    The first example of synchrotron X-ray fluorescence imaging of cultured mammalian cells in cyclic peptide research is reported. The study reports the first quantitative analysis of the incorporation of a bromine-labelled cyclic RGD peptide and its effects on the biodistribution of endogenous elements (for example, K and Cl) within individual tumor cells. The first example of synchrotron X-ray fluorescence imaging of cultured mammalian cells in cyclic peptide research is reported. The study reports the first quantitative analysis of the incorporation of a bromine-labelled cyclic RGD peptide and its effects on the biodistribution of endogenous elements (for example, K and Cl) within individual tumor cells

  20. Constraining cyclic peptides to mimic protein structure motifs

    Hill, Timothy A.; Shepherd, Nicholas E.; Diness, Frederik;

    2014-01-01

    Many proteins exert their biological activities through small exposed surface regions called epitopes that are folded peptides of well-defined three-dimensional structures. Short synthetic peptide sequences corresponding to these bioactive protein surfaces do not form thermodynamically stable pro...

  1. Synthesis and in vitro evaluation of cyclic NGR peptide targeted thermally sensitive liposome

    NEGUSSIE, AYELE H.; Miller, Jenna L.; Reddy, Goutham; Drake, Steven K.; Wood, Bradford J.; Dreher, Matthew R.

    2010-01-01

    The Asn-Gly-Arg (NGR) motif in both cyclic and linear form has previously been shown to specifically bind to CD13/aminopeptidase N that is selectively overexpressed in tumor vasculature and some tumor cells. However, previous versions of cyclic NGR used a liable disulfide bridge between cysteine residues that may be problematic for liposome targeting due to disulfide bond formation between adjacent peptides on the liposomal surface. In this study, we report the design, synthesis, and characte...

  2. The binding mechanism of a peptidic cyclic serine protease inhibitor

    Jiang, Longguang; Svane, Anna S P; Sørensen, Hans Peter; Jensen, Jan K; Hosseini, Masood; Chen, Zhuo; Weydert, Caroline; Nielsen, Jakob T; Christensen, Anni; Yuan, Cai; Jensen, Knud Jørgen; Nielsen, Niels Chr; Malmendal, Anders; Huang, Mingdong; Andreasen, Peter

    2011-01-01

    Serine proteases are classical objects for studies of catalytic and inhibitory mechanisms as well as interesting as therapeutic targets. Since small-molecule serine protease inhibitors generally suffer from specificity problems, peptidic inhibitors, isolated from phage-displayed peptide libraries......, have attracted considerable attention. Here, we have investigated the mechanism of binding of peptidic inhibitors to serine protease targets. Our model is upain-1 (CSWRGLENHRMC), a disulfide-bond-constrained competitive inhibitor of human urokinase-type plasminogen activator with a noncanonical...... inhibitory mechanism and an unusually high specificity. Using a number of modified variants of upain-1, we characterised the upain-1-urokinase-type plasminogen activator complex using X-ray crystal structure analysis, determined a model of the peptide in solution by NMR spectroscopy, and analysed binding...

  3. Comparative distribution study of /sup 111/In-labelled DTPA and TTHA monoclonal antibody conjugates in a choriocarcinoma xenograft model

    Buckley, R.G.; Barnett, P.; Searle, F.; Pedley, R.; Boden, J.A.

    1986-11-01

    Conjugates of the chelating agents DTPA and TTHA with a monoclonal anti-HCG were prepared. The tissue distribution of the /sup 111/In-Labelled conjugates and also /sup 111/In-citrate was studied in mice bearing human choriocarcinoma xenografts. The antibody conjugates both gave high liver and spleen radionuclide accumulation. Elevated femur levels were observed for the TTHA conjugate and /sup 111/In-citrate. Generally the DTPA conjugate showed the highest tumor-tissue ratios, although its tumor/blood ratio was lower than the other two materials. The results infer that the DTPA conjugate has the greatest utility as an imaging agent but that it would require a background subtraction technique.

  4. Serial in vivo imaging of the porcine heart after percutaneous, intramyocardially injected 111In-labeled human mesenchymal stromal cells

    Lyngbaek, Stig; Ripa, Rasmus S; Haack-Sørensen, Mandana;

    2010-01-01

    This pilot trial aimed to investigate the utilization of (111)In-labeling of mesenchymal stromal cells (MSC) for in vivo tracking after intramyocardial transplantation in a xenotransplantation model with gender mismatched cells. Human male MSC were expanded ex vivo and labeled with (111)In......-tropolone. Ten female pigs were included. The labeled cells were transplanted intramyocardially using a percutaneous injection system. The (111)In activity was determined using gamma camera imaging. Excised hearts were analyzed by fluorescence in situ hybridization (FISH) and microscopy. Gamma camera imaging...... revealed focal cardiac (111)In accumulations up to 6 days after injection (N = 4). No MSC could be identified with FISH, and microscopy identified widespread acute inflammation. Focal (111)In accumulation, inflammation but no human MSC were similarly seen in pigs (N = 2) after immunosuppression. A...

  5. Serial in vivo imaging of the porcine heart after percutaneous, intramyocardially injected (111)In-labeled human mesenchymal stromal cells

    Lyngbæk, Stig; Ripa, Rasmus Sejersten; Haack-Sørensen, Mandana;

    2009-01-01

    This pilot trial aimed to investigate the utilization of (111)In-labeling of mesenchymal stromal cells (MSC) for in vivo tracking after intramyocardial transplantation in a xenotransplantation model with gender mismatched cells. Human male MSC were expanded ex vivo and labeled with (111)In......-tropolone. Ten female pigs were included. The labeled cells were transplanted intramyocardially using a percutaneous injection system. The (111)In activity was determined using gamma camera imaging. Excised hearts were analyzed by fluorescence in situ hybridization (FISH) and microscopy. Gamma camera imaging...... revealed focal cardiac (111)In accumulations up to 6 days after injection (N = 4). No MSC could be identified with FISH, and microscopy identified widespread acute inflammation. Focal (111)In accumulation, inflammation but no human MSC were similarly seen in pigs (N = 2) after immunosuppression. A...

  6. New 111In labeling of IgG: 111In-oxine mediated chelation

    Current methods of 111In chelate conjugation labeling of antibodies expose the protein to pH 5-6 during 111In chelation. These conditions could be detrimental if the antibody is acid labile. We have successfully labeled human IgG via the cyclic anhydride of DPTA and 111In-oxyquinoline(oxine). Chelation was achieved at pH 6.9-8.4 and was complete within 1 min at room temperature. The chelation was sensitive to trace metal contamination on labware and in some reagents (including commercial 111In-oxine). (author)

  7. CYCLONE—A Utility for De Novo Sequencing of Microbial Cyclic Peptides

    Kavan, Daniel; Kuzma, Marek; Lemr, Karel; Schug, Kevin A.; Havlicek, Vladimir

    2013-08-01

    We have developed a de novo sequencing software tool (CYCLONE) and applied it for determination of cyclic peptides. The program uses a non-redundant database of 312 nonribosomal building blocks identified to date in bacteria and fungi (more than 230 additional residues in the database list were isobaric). The software was used to fully characterize the tandem mass spectrum of several cyclic peptides and provide sequence tags. The general strategy of the script was based on fragment ion pre-characterization to accomplish unambiguous b-ion series assignments. Showcase examples were a cyclic tetradepsipeptide beauverolide, a cyclic hexadepsipeptide roseotoxin A, a lasso-like hexapeptide pseudacyclin A, and a cyclic undecapeptide cyclosporin A. The extent of ion scrambling in smaller peptides was as low as 5 % of total ion current; this demonstrated the feasibility of CYCLONE de novo sequencing. The robustness of the script was also tested against database sets of various sizes and isotope-containing data. It can be downloaded from the http://ms.biomed.cas.cz/MSTools/.

  8. CYCLONE-A Utility for De Novo Sequencing of Microbial Cyclic Peptides

    Kavan, Daniel; Kuzma, Marek; Lemr, Karel; Schug, K. A.; Havlíček, Vladimír

    2013-01-01

    Roč. 24, č. 8 (2013), s. 1177-1184. ISSN 1044-0305 R&D Projects: GA MŠk(CZ) ME10013; GA ČR(CZ) GAP206/12/1150 Institutional support: RVO:61388971 Keywords : Peptide * Cyclic * Sequencing Subject RIV: CE - Biochemistry Impact factor: 3.193, year: 2013

  9. mMass as a Software Tool for the Annotation of Cyclic Peptide Tandem Mass Spectra

    Niedermeyer, T. H. J.; Strohalm, Martin

    2012-01-01

    Roč. 7, č. 9 (2012), e44913. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) ME10013 Institutional research plan: CEZ:AV0Z50200510 Keywords : cyclic peptides * nMass Subject RIV: CE - Biochemistry Impact factor: 3.730, year: 2012

  10. Strong combined gene-environment effects in anti-cyclic citrullinated peptide-positive rheumatoid arthritis

    Pedersen, Line Merete Blak; Jacobsen, Søren; Garred, Peter;

    2007-01-01

    To study the role of shared epitope (SE) susceptibility genes, alone and in combination with tobacco smoking and other environmental risk factors, for risk of subtypes of rheumatoid arthritis (RA) defined by the presence or absence of serum antibodies against cyclic citrullinated peptides (CCPs)....

  11. Electrophoretic Transport of Na(+) and K(+) Ions Within Cyclic Peptide Nanotubes.

    Carvajal-Diaz, Jennifer A; Cagin, Tahir

    2016-08-18

    One of the most important applications of cyclic peptide nanotubes (CPNTs) is their potential to be used as artificial ion channels. Natural ion channels are large and complex membrane proteins, which are very expensive, difficult to isolate, and sensible to denaturation; for this reason, artificial ion channels are an important alternative, as they can be produced by simple and inexpensive synthetic chemistry paths, allowing manipulation of properties and enhancement of ion selectivity properties. Artificial ion channels can be used as component in molecular sensors and novel therapeutic agents. Here, the electrophoretic transport of Na(+) and K(+) ions within cyclic peptide nanotubes is investigated by using molecular dynamic simulations. The effect of electric field in the stability of peptide nanotubes was studied by calculating the root mean square deviation curves. Results show that the stability for CPNTs decreases for higher electric fields. Selective transport of cations within the hydrophilic tubes was observed and the negative Cl(-) ions did not enter the peptide nanotubes during the simulation. Radial distribution functions were calculated to describe structural properties and coordination numbers and changes in the first and second hydration shell were observed for the transport of Na(+) and K(+) inside of cyclic peptide nanotubes. However, no effect on coordination number was observed. Diffusion coefficients were calculated from the mean square deviation curves and the Na(+) ion showed higher mobility than the K(+) ion as observed in equivalent experimental studies. The values for diffusion coefficients are comparable with previous calculations in protein channels of equivalent sizes. PMID:27448165

  12. Optimization of a cyclic peptide inhibitor of Ser/Thr phosphatase PPM1D (Wip1).

    Hayashi, Ryo; Tanoue, Kan; Durell, Stewart R; Chatterjee, Deb K; Jenkins, Lisa M Miller; Appella, Daniel H; Appella, Ettore

    2011-05-31

    PPM1D (PP2Cδ or Wip1) was identified as a wild-type p53-induced Ser/Thr phosphatase that accumulates after DNA damage and classified into the PP2C family. It dephosphorylates and inactivates several proteins critical for cellular stress responses, including p38 MAPK, p53, and ATM. Furthermore, PPM1D is amplified and/or overexpressed in a number of human cancers. Thus, inhibition of its activity could constitute an important new strategy for therapeutic intervention to halt the progression of several different cancers. Previously, we reported the development of a cyclic thioether peptide with low micromolar inhibitory activity toward PPM1D. Here, we describe important improvements in the inhibitory activity of this class of cyclic peptides and also present a binding model based upon the results. We found that specific interaction of an aromatic ring at the X1 position and negative charge at the X5 and X6 positions significantly increased the inhibitory activity of the cyclic peptide, with the optimized molecule having a K(i) of 110 nM. To the best of our knowledge, this represents the highest inhibitory activity reported for an inhibitor of PPM1D. We further developed an inhibitor selective for PPM1D over PPM1A with a K(i) of 2.9 μM. Optimization of the cyclic peptide and mutagenesis experiments suggest that a highly basic loop unique to PPM1D is related to substrate specificity. We propose a new model for the catalytic site of PPM1D and inhibition by the cyclic peptides that will be useful both for the subsequent design of PPM1D inhibitors and for identification of new substrates. PMID:21528848

  13. Modulation of Backbone Flexibility for Effective Dissociation of Antibacterial and Hemolytic Activity in Cyclic Peptides.

    Oddo, Alberto; Thomsen, Thomas T; Britt, Hannah M; Løbner-Olesen, Anders; Thulstrup, Peter W; Sanderson, John M; Hansen, Paul R

    2016-08-11

    Bacterial resistance to antibiotic therapy is on the rise and threatens to evolve into a worldwide emergency: alternative solutions to current therapies are urgently needed. Cationic amphipathic peptides are potent membrane-active agents that hold promise as the next-generation therapy for multidrug-resistant infections. The peptides' behavior upon encountering the bacterial cell wall is crucial, and much effort has been dedicated to the investigation and optimization of this amphipathicity-driven interaction. In this study we examined the interaction of a novel series of nine-membered flexible cyclic AMPs with liposomes mimicking the characteristics of bacterial membranes. Employed techniques included circular dichroism and marker release assays, as well as microbiological experiments. Our analysis was aimed at correlating ring flexibility with their antimicrobial, hemolytic, and membrane activity. By doing so, we obtained useful insights to guide the optimization of cyclic antimicrobial peptides via modulation of their backbone flexibility without loss of activity. PMID:27563396

  14. Mass spectrometric and bioinformatics approaches to characterizing of cyclic non-ribosomal peptides and ribosomally encoded peptide antibiotic

    Liu, Wei-Ting

    2009-01-01

    Natural products are a crucial component in drug discovery because of their considerable pharmaceutical properties. Cyclic non-ribosomally peptides are one category of natural products featured by containing non-standard amino acids and lactam or lactone structures, thus increasing the complexity of the resulting tandem mass spectrometry data. Cyclosporin, microcystins and nodularins all are well-known examples and have notable pharmacologically importance. In this current work, by collaborat...

  15. Gigahertz nanomechanical oscillators based on ions inside cyclic peptide nanotubes: a continuum study

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-08-01

    The present work aims to investigate the mechanical oscillatory behavior of ions, and in particular {Li+, Na+, Rb+} and {Cl-} ions, inside a cyclo[(- d-Ala- l-Ala)4-] peptide nanotube using the continuum approximation along with the 6-12 Lennard-Jones (LJ) potential function. Assuming that each peptide unit is comprised of an inner and an outer tube, the van der Waals (vdW) potential energy and interaction force between an ion and a cyclic peptide nanotube (CPN) are determined analytically. With respect to the present formulations, a detailed parametric study is conducted on the vdW potential energy and interaction force distributions by varying the number of peptide units. Employing the conservation of mechanical energy principle, a novel expression for precise evaluation of oscillation frequency is introduced. To verify the accuracy of the proposed frequency expression, the results obtained from energy equation are compared with the ones predicted through solving the equation of motion numerically. The effects of number of peptide units and initial conditions including initial separation distance and velocity on the oscillatory behavior of various ions inside CPNs are explored. Among the considered ions, {Cl-} ion is found to generate the highest frequency. According to the potential energy profile, one oscillatory zone for one peptide unit and different oscillatory zones for more than one peptide unit are observed. Numerical results indicate that optimal frequency decreases with increasing the number of peptide units and almost remains unchanged when the number of peptide units exceeds four.

  16. Influence of an aliphatic linker between DOTA and synthetic ZHER2:342 Affibody molecule on targeting properties of the 111In-labeled conjugate

    Introduction: Affibody molecules are small (∼6.5 kDa) scaffold proteins suitable for radionuclide imaging of tumor-associated molecular targets. Site-specific labeling of Affibody molecules made by peptide synthesis can be achieved by coupling a chelator to N-terminus in the last synthesis step. The goal of this study was to evaluate the influence of a 6-aminohexanoic linker between DOTA and ZHER2:342 on targeting properties of 111In-labeled conjugate. Methods: A DOTA-conjugated 6-aminohexanoic linker-containing variant of ZHER2:342 (ABY-003) was produced by peptide synthesis, and the in vitro binding affinity, specificity and cellular processing were evaluated. The biodistribution of 111In-ABY-003 in normal mice was compared to 111In-ABY-002 (DOTA-ZHER2:342-pep2) lacking the linker. Tumor-targeting properties of 111In-ABY-003 were evaluated in mice bearing HER2-expressing xenografts. Results: The dissociation constant of ABY-003 was in the low picomolar range, slightly higher than for ABY-002. 111In-ABY-003 bound specifically to HER2-expressing cells in vitro. The cellular retention was efficient but slightly worse than for 111In-ABY-002. In normal mice, the clearance of 111In-ABY-003 from blood and other tissues was slightly but significantly faster compared to 111In-ABY-002. Targeting of HER2-expressing xenografts by 111In-ABY-003 was receptor-specific. Due to faster clearance, the tumor-to-blood ratio for 111In-ABY-003 at 4 h postinjection was improved compared to 111In-ABY-002. The capacity of 111In-ABY-003 to visualize HER2-expressing tumors was confirmed by gamma camera imaging. Conclusions: A 6-aminohexanoic linker between the DOTA chelator and N-terminus of synthetic ZHER2:342 had a measurable effect on affinity, cellular retention of radioactivity and blood clearance. The linker might be used for modulation of targeting properties of Affibody molecules.

  17. Antigene radiotherapy using 111In-labeled Triplex-Forming Oligonucleotide targeting human N-myc gene

    In this study, by selecting the polypurine-polypyrimidine stretch (2950-2978) in the human N-myc gene as a target, the 111In-labeled TFO targeting human N-myc gene (N-mycTFO111In) was tested for its cellular uptake and nuclear localization in vitro and in vivo. The total cellular uptake of TFO after the incubation of various normal and cancer cells with TFO for 24 h was 20-54.8% of the injected dose (% ID), and the nuclear localization was 6.59-30.0% ID, depending on cell lines. The highest cellular uptake was found in the human neuroblastoma SK-N-DZ (54.8% ID), human mammary ductal carcinoma T47-D (54% ID), human acute T cell leukemia Jurkat (54% ID), and multidrug-resistant human breast adenocarcinoma MCF7/TH (49.5% ID). The lowest was in the human normal mammary epithelium MCF10A (20.0% ID). The highest nuclear localization was found in MCF7/TH (30% ID) and SK-N-DZ (28.7% ID). The lowest was in MCF10A (6.59% ID). We next injected TFO into human mammary tumor-xenografted Balb/c nude mice. Tumor targeting of TFO in vivo reached its maximum peak 5 h after the intravenous injection in three types of tumor models. They are 21.0±3.23% ID per gram of tissue (% ID/g) for MCF7/TH, 7.77 ±2.11% ID/g for MCF7, and 4.53 ±%1.20% ID/g for MCF10A. The TFO blood level decreased from 8.00 ±0.90% ID/g 15min after the injection, to 1.30 ±0.30% ID/g after 19 h. The kidney TFO level increased rapidly from 5.93 ±0.94% ID/g after 15min, to 25.1± 5.60% ID/g after 19 h. A high TFO level (19.7-24.5% ID/g) in the lever was maintained until 19 h after the injection. Therefore, we suggest that the 111In-labeled N-myc-targeting TFO, a promising modality for nanoexplosive gene therapy, could effectively target the nucleus of the multidrug-resistant breast carcinoma MCF7/TH in vitro and in vivo

  18. Antigene radiotherapy using {sup 111}In-labeled Triplex-Forming Oligonucleotide targeting human N-myc gene

    Choi, J. G.; Son, S. H.; Shin, E. K.; Ryu, Y. M.; Park, Y. H.; Park, J. H.; Seo, S. H.; Lee, S. H.; Lee, J. H.; Kim, M. G. [Korea University, Seoul (Korea, Republic of)

    2004-07-01

    In this study, by selecting the polypurine-polypyrimidine stretch (2950-2978) in the human N-myc gene as a target, the {sup 111}In-labeled TFO targeting human N-myc gene (N-mycTFO{sup 111}In) was tested for its cellular uptake and nuclear localization in vitro and in vivo. The total cellular uptake of TFO after the incubation of various normal and cancer cells with TFO for 24 h was 20-54.8% of the injected dose (% ID), and the nuclear localization was 6.59-30.0% ID, depending on cell lines. The highest cellular uptake was found in the human neuroblastoma SK-N-DZ (54.8% ID), human mammary ductal carcinoma T47-D (54% ID), human acute T cell leukemia Jurkat (54% ID), and multidrug-resistant human breast adenocarcinoma MCF7/TH (49.5% ID). The lowest was in the human normal mammary epithelium MCF10A (20.0% ID). The highest nuclear localization was found in MCF7/TH (30% ID) and SK-N-DZ (28.7% ID). The lowest was in MCF10A (6.59% ID). We next injected TFO into human mammary tumor-xenografted Balb/c nude mice. Tumor targeting of TFO in vivo reached its maximum peak 5 h after the intravenous injection in three types of tumor models. They are 21.0{+-}3.23% ID per gram of tissue (% ID/g) for MCF7/TH, 7.77 {+-}2.11% ID/g for MCF7, and 4.53 {+-}%1.20% ID/g for MCF10A. The TFO blood level decreased from 8.00 {+-}0.90% ID/g 15min after the injection, to 1.30 {+-}0.30% ID/g after 19 h. The kidney TFO level increased rapidly from 5.93 {+-}0.94% ID/g after 15min, to 25.1{+-} 5.60% ID/g after 19 h. A high TFO level (19.7-24.5% ID/g) in the lever was maintained until 19 h after the injection. Therefore, we suggest that the {sup 111}In-labeled N-myc-targeting TFO, a promising modality for nanoexplosive gene therapy, could effectively target the nucleus of the multidrug-resistant breast carcinoma MCF7/TH in vitro and in vivo.

  19. Comparative biodistribution of 12 (1)(1)(1)In-labelled gastrin/CCK2 receptor-targeting peptides

    Laverman, P.; Joosten, L.; Eek, A.; Roosenburg, S.; Peitl, P.K.; Maina, T.; Macke, H.; Aloj, L.; Guggenberg, E. von; Sosabowski, J.K.; Jong, M. de; Reubi, J.C.; Oyen, W.J.G.; Boerman, O.C.

    2011-01-01

    PURPOSE: Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several C

  20. Antibacterial agents based on the cyclic D,L-α-peptide architecture

    Fernandez-Lopez, Sara; Kim, Hui-Sun; Choi, Ellen C.; Delgado, Mercedes; Granja, Juan R.; Khasanov, Alisher; Kraehenbuehl, Karin; Long, Georgina; Weinberger, Dana A.; Wilcoxen, Keith M.; Ghadiri, M. Reza

    2001-07-01

    The rapid emergence of bacterial infections that are resistant to many drugs underscores the need for new therapeutic agents. Here we report that six- and eight-residue cyclic D,L-α-peptides act preferentially on Gram-positive and/or Gram-negative bacterial membranes compared to mammalian cells, increase membrane permeability, collapse transmembrane ion potentials, and cause rapid cell death. The effectiveness of this class of materials as selective antibacterial agents is highlighted by the high efficacy observed against lethal methicillin-resistant Staphylococcus aureus infections in mice. Cyclic D,L-α-peptides are proteolytically stable, easy to synthesize, and can be derived from a potentially vast membrane-active sequence space. The unique abiotic structure of the cyclic peptides and their quick bactericidal action may also contribute to limit temporal acquirement of drug resistant bacteria. The low molecular weight D,L-α-peptides offer an attractive complement to the current arsenal of naturally derived antibiotics, and hold considerable potential in combating a variety of existing and emerging infectious diseases.

  1. Kinetics of leukocyte sequestration in the lungs of acutely septic primates: A study using 111In-labeled autologous leukocytes

    To further clarify the role of leukocytes in the pathogenesis of ARDS, we studied the localization and kinetics of leukocyte migration using 111In-labeled autologous white cell scans (111In wbc scans) in four primates made acutely septic with infusions of Escherichia coli. Whole body images were obtained with a gamma camera and were acquired on computer every 15 min beginning immediately after the E. coli infusion. Simultaneous measurements of C5a and peripheral blood leukocyte count were also obtained. Within 5 min of initiating sepsis, three major events occurred: complement activation as measured by the production of C5a, a profound fall in peripheral leukocyte count, and a significant increase in the sequestration of leukocytes in the lungs. The pulmonary sequestration reached a peak at 15 min with a mean of 152% of baseline activity. This sequestration consisted of a population that was predominantly neutrophils. Damage to the pulmonary capillary endothelium was demonstrated by an increase in extravascular lung water. The results support a role for neutrophils and complement as mediators in the pathogenesis of ARDS

  2. Thrombus imaging with [sup 99m]Tc-HMPAO-labeled platelets and [sup 111]In-labeled monoclonal antifibrin antibodies

    Vorne, M.S.; Honkanen, T.T.; Lantto, T.J.; Laitinen, R.O.; Karppinen, K.J.; Jauhola, S.V. (Depts. of Nuclear Medicine and Diagnostic Radiology, Paeijaet-Haeme Central Hospital, Lahti (Finland))

    1993-01-01

    Eighteen patients with suspicion of deep venous thrombosis (DVT) in the lower extremities were imaged both with autologous [sup 99m]Tc-HMPAO-labeled platelets (Tc-PLT) and [sup 111]In-labeled monoclonal antifibrin antibodies (In-MoAbs) on the same day. Precence or absence of thrombosis was verified by venography. Tc-PLT was given i.v. followed after 30 min by In-MoAbs. Anterior and posterior projections of the lower extremities were obtained with a large field-of-view gamma camera at 5 to 25 min, 2 h, 4 to 6 h, and 20 h after administration of the marker. Both Tc-PLT and In-MoAbs detected DVT well but less frequently than venography. Thrombi were visualized at 2 to 4 h after injection. The quality of images was better with Tc-PLT than with In-MoAbs. In the patients treated during the study, heparin significantly (p< 0.01) inhibited the uptake of Tc-PLT but not of In-MoAbs. We conclude that both Tc-PLT and In-MoAbs are suitable agents for the detection of DVT especially in patients without anticoagulation. (orig.).

  3. The use of 111In-labelled lymphocyte imaging to evaluate graft rejection following cardiac transplantation in dogs

    Lymphocytes separated from venous blood from six dogs who had heterotopic cardiac transplants have been labeled using 111In-oxine. Labeled lymphocytes were reinjected into the dogs and imaging for the heart carried out over the successive 3 or 4 days. For comparison serial ECGs and punch biopsies of the heart was clearly visible in three of the six dogs, faintly visible in two and not seen in one. 630 μCi111In was used in the dog where no uptake was seen and subsequent studies showed this amount of the radiopharmaceutical was toxic to lymphocytes. In the remaining five dogs the mean ratio of uptake of 111In in donor to recipient heart was 14:1 (range 6.5:1-21:1). The lack of substantial uptake in the transplanted heart of two dogs is attributed to a delay in rejection relative to the time the labled lymphocytes were injected. The results suggest that 111In-labeled lymphocytes have potential as a noninvasive test for detecting rejection of cardiac transplants. (orig.)

  4. Cyclic Peptide-Decorated Self-Assembled Nanohybrids for Selective Recognition and Detection of Multivalent RNAs.

    Choi, Jun Shik; Han, So-hee; Kim, Hyoseok; Lim, Yong-Beom

    2016-03-16

    Although there has been substantial advancement in the development of nanostructures, the development of self-assembled nanostructures that can selectively recognize multivalent targets has been very difficult. Here we show the proof of concept that topology-controlled peptide nanoassemblies can selectively recognize and detect a multivalent RNA target. We compared the differential behaviors of peptides in a linear or cyclic topology in terms of peptide-gold nanoparticle hybrid nanostructure formation, conformational stabilization, monovalent and multivalent RNA binding in vitro, and multivalent RNA recognition in live cells. When the topology-dependent selectivity amplification of the cyclic peptide hybrids is combined with the noninvasive nature of dark-field microscopy, the cellular localization of the viral Rev response element (RRE) RNA can be monitored in situ. Because intracellular interactions are often mediated by overlapping binding partners with weak affinity, the topology-controlled peptide assemblies can provide a versatile means to convert weak ligands into multivalent ligands with high affinity and selectivity. PMID:26886413

  5. Cyclic peptide inhibitors of the β-sliding clamp in Staphylococcus aureus

    Kjelstrup, Susanne; Hansen, Paula Melo Paulon; Thomsen, Line Elnif; Hansen, Paul Robert; Løbner-Olesen, Anders

    2013-01-01

    Interaction between pairs of Staphylococcus aureus replication proteins was detected in an Escherichia coli based two-hybrid analysis. A reverse two-hybrid system was constructed for selection of compounds that hindered interaction between interacting protein pairs. A number of cyclic peptides, f...... minimum inhibitory concentration was ∼50 μg/ml for S. aureus cells. These compounds may serve as lead candidates for future development into novel classes of antibiotics as well as provide information on the function of the S. aureus replication process.......Interaction between pairs of Staphylococcus aureus replication proteins was detected in an Escherichia coli based two-hybrid analysis. A reverse two-hybrid system was constructed for selection of compounds that hindered interaction between interacting protein pairs. A number of cyclic peptides...

  6. Purification and Identification of Two Antifungal Cyclic Peptides Produced by Bacillus amyloliquefaciens L-H15.

    Han, Yuzhu; Zhang, Bao; Shen, Qian; You, Chengzhen; Yu, Yaqiong; Li, Pinglan; Shang, Qingmao

    2015-08-01

    Bacillus amyloliquefaciens L-H15 with broad spectrum antifungal activity was used as a biocontrol agent to suppress Fusarium oxysporum and other soil-borne fungal plant pathogens. Two antifungal fractions were isolated by bioactivity-guided reversed-phase high-performance liquid chromatography. The two compounds were identified by tandem Q-TOF mass spectroscopy as C15 Iturin A (1) and a novel cyclic peptide with a molecular weight of 852.4 Da (2). Both compounds showed good inhibitory activities against three plant fungal pathogens in cylinder-plate diffusion assay. To our best knowledge, this is the first report on a cyclic antifungal peptide with a molecular weight of 852.4 Da. The strong antifungal activity suggests that the B. amyloliquefaciens L-H15 and its bioactive components might provide an alternative resource for the biocontrol of plant diseases and sustainable agriculture. PMID:26123083

  7. Cyclic peptides-assisted trans- port of metal ions across liquid-organic membrane

    2001-01-01

    The formation of alkali and alkaline-earth metal picrate complexes with cyclo(Pro-Gly)n ionophores (1, n = 3; 2, n = 4) can facilitate the migration of metal ions across a bulk liquid CH2Cl2 membrane. The migration behavior was studied by measuring the solution absorption at 356 nm, using a UV/Vis spectrophotometer, and the rates can be determined by comparing the initial absorption of donor solutions with the absorption of the corresponding receiver solutions as the function of time. It was found that cyclic peptide 1 shows higher transport activity for the studied alkali and alkaline-earth metal ions than compound 2, which is related to the backbone flexibility of the cyclic peptides. The findings in this work suggest that the rate of ionophore-facilitated ion transport depends not only on the ability of complex forma-tion in aqueous phase, but also on the ability of complex dissociation in organic phase.

  8. Peptide Macrocycles Featuring a Backbone Secondary Amine: A Convenient Strategy for the Synthesis of Lipidated Cyclic and Bicyclic Peptides on Solid Support

    Oddo, Alberto; Münzker, Lena; Hansen, Paul Robert

    2015-01-01

    A convenient strategy for the on-resin synthesis of macrocyclic peptides (3- to 13-mers) via intramolecular halide substitution by a diamino acid is described. The method is compatible with standard Fmoc/tBu SPPS and affords a tail-to-side-chain macrocyclic peptide featuring an endocyclic secondary...... amine. This functional group is still reactive toward acylation, allowing for the continuation of the synthesis. An application to the synthesis of lipidated cyclic and bicyclic antimicrobial peptides is presented....

  9. Atrial natriuretic peptide receptor heterogeneity and effects on cyclic GMP accumulation

    Leitman, D.C.

    1988-01-01

    The effects of atrial natriuretic peptide (ANP), oxytocin (OT) and vasopressin (AVP) on guanylate cyclase activity and cyclic GMP accumulation were examined, since these hormones appear to be intimately associated with blood pressure and intravascular volume homeostasis. ANP was found to increase cyclic GMP accumulation in ten cell culture systems, which were derived from blood vessels, adrenal cortex, kidney, lung, testes and mammary gland. ANP receptors were characterized in intact cultured cells using {sup 125}I-ANP{sub 8-33}. Specific {sup 125}I-ANP binding was saturable and of high affinity. Scratchard analysis of the binding data for all cell types exhibited a straight line, indicating that these cells possessed a single class of binding sites. Despite the presence of linear Scatchard plots, these studies demonstrated that cultured cells possess two functionally and physically distinct ANP-binding sites. Most of the ANP-binding sites in cultured cells have a molecular size of 66,000 daltons under reducing conditions. The identification of cultured cell types in which hormones (ANP and oxytocin) regulate guanylate cyclase activity and increase cyclic GMP synthesis will provide valuable systems to determine the mechanisms of hormone-receptor coupling to guanylate cyclase and the cellular processes regulated by cyclic GMP.

  10. Atrial natriuretic peptide receptor heterogeneity and effects on cyclic GMP accumulation

    The effects of atrial natriuretic peptide (ANP), oxytocin (OT) and vasopressin (AVP) on guanylate cyclase activity and cyclic GMP accumulation were examined, since these hormones appear to be intimately associated with blood pressure and intravascular volume homeostasis. ANP was found to increase cyclic GMP accumulation in ten cell culture systems, which were derived from blood vessels, adrenal cortex, kidney, lung, testes and mammary gland. ANP receptors were characterized in intact cultured cells using 125I-ANP8-33. Specific 125I-ANP binding was saturable and of high affinity. Scratchard analysis of the binding data for all cell types exhibited a straight line, indicating that these cells possessed a single class of binding sites. Despite the presence of linear Scatchard plots, these studies demonstrated that cultured cells possess two functionally and physically distinct ANP-binding sites. Most of the ANP-binding sites in cultured cells have a molecular size of 66,000 daltons under reducing conditions. The identification of cultured cell types in which hormones (ANP and oxytocin) regulate guanylate cyclase activity and increase cyclic GMP synthesis will provide valuable systems to determine the mechanisms of hormone-receptor coupling to guanylate cyclase and the cellular processes regulated by cyclic GMP

  11. Crystal structure of human insulin-regulated aminopeptidase with specificity for cyclic peptides.

    Hermans, Stefan J; Ascher, David B; Hancock, Nancy C; Holien, Jessica K; Michell, Belinda J; Chai, Siew Yeen; Morton, Craig J; Parker, Michael W

    2015-02-01

    Insulin-regulated aminopeptidase (IRAP or oxytocinase) is a membrane-bound zinc-metallopeptidase that cleaves neuroactive peptides in the brain and produces memory enhancing effects when inhibited. We have determined the crystal structure of human IRAP revealing a closed, four domain arrangement with a large, mostly buried cavity abutting the active site. The structure reveals that the GAMEN exopeptidase loop adopts a very different conformation from other aminopeptidases, thus explaining IRAP's unique specificity for cyclic peptides such as oxytocin and vasopressin. Computational docking of a series of IRAP-specific cognitive enhancers into the crystal structure provides a molecular basis for their structure-activity relationships and demonstrates that the structure will be a powerful tool in the development of new classes of cognitive enhancers for treating a variety of memory disorders such as Alzheimer's disease. PMID:25408552

  12. Design and Optimisation of Bioactive Cyclic Peptides: Generation of a Down-Regulator of TNF Secretion

    Roger New

    2014-12-01

    Full Text Available Although strong binding interactions between protein receptor and ligand do not require the participation of a large number of amino acids in either site, short peptide chains are generally poor at recreating the types of protein-protein interactions which take place during cell recognition and signalling process, probably because their flexible backbones prevent the side chains from forming sufficiently rigid and stable epitopes, which can take part in binding with the desired strength and specificity. In a recently-reported study, it was shown that a proto-epitope containing F, R and S amino acids has the ability to down-regulate TNF secretion by macrophages. This paper extends these findings, putting those amino acids into a short cyclic peptide scaffold, and determining the optimal configuration required to overcome the problems of conformational instability, and give rise to molecules which have potential as therapeutic agents in human disease, such as rheumatoid arthritis.

  13. Continuum modeling investigation of gigahertz oscillators based on a C60 fullerene inside cyclic peptide nanotubes

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-02-01

    Research concerning the fabrication of nano-oscillators with operating frequency in the gigahertz (GHz) range has become a focal point in recent years. In this paper, a new type of GHz oscillators is introduced based on a C60 fullerene inside a cyclic peptide nanotube (CPN). To study the dynamic behavior of such nano-oscillators, using the continuum approximation in conjunction with the 6-12 Lennard-Jones (LJ) potential function, analytical expressions are derived to determine the van der Waals (vdW) potential energy and interaction force between the two interacting molecules. Employing Newton's second law, the equation of motion is solved numerically to arrive at the telescopic oscillatory motion of a C60 fullerene inside CPNs. It is shown that the fullerene molecule exhibits different kinds of oscillation inside peptide nanotubes which are sensitive to the system parameters. Furthermore, for the precise evaluation of the oscillation frequency, a novel semi-analytical expression is proposed based on the conservation of the mechanical energy principle. Numerical results are presented to comprehensively study the effects of the number of peptide units and initial conditions (initial separation distance and velocity) on the oscillatory behavior of C60 -CPN oscillators. It is found out that for peptide nanotubes comprised of one unit, the maximum achievable frequency is obtained when the inner core oscillates with respect to its preferred positions located outside the tube, while for other numbers of peptide units, such frequency is obtained when the inner core oscillates with respect to the preferred positions situated in the space between the two first or the two last units. It is further found out that four peptide units are sufficient to obtain the optimal frequency.

  14. Effect of the amino acid composition of cyclic peptides on their self-assembly in lipid bilayers.

    Danial, Maarten; Perrier, Sébastien; Jolliffe, Katrina A

    2015-02-28

    The effect of amino acid composition on the formation of transmembrane channels in lipid bilayers upon self-assembly of alt-(L,D)-α-cyclic octapeptides has been investigated. Cyclic peptides comprising D-leucine, alternating with different combinations of L-azidolysine, L-lysine(Alloc), L-lysine and L-tryptophan were synthesized and the size of pores formed via self-assembly of these molecules in lipid bilayers was elucidated using large unilamellar vesicle fluorescence assays and dynamic light scattering. Pore formation was examined in large unilamellar vesicles made up of egg yolk phosphatidylcholine or Escherichia coli total lipid extract. From these analyses, we have established that cyclic peptides with charged side chains form large pores while those with neutral side chains form unimeric pores. Furthermore, the cyclic peptides that consist of non-symmetric amino acid configurations possess a higher membrane activity than the cyclic peptides with a symmetric amino acid configuration. In addition, we have found that peptide amphiphilicity plays a vital role in selective partitioning between bilayers that consist of egg yolk phosphatidylcholine and those comprised of E. coli total lipid extract. These results suggest that selective transbilayer channel formation via self-assembly may be a viable alternative for many applications that currently use more expensive, multistep synthesis methods. PMID:25566760

  15. A High-Adhesive Lysine-Cyclic RGD Peptide Designed for Selective Cell Retention Technology.

    Luo, Keyu; Mei, Tieniu; Li, Zhiqiang; Deng, Moyuan; Zhang, Zehua; Hou, Tianyong; Dong, Shiwu; Xie, Zhao; Xu, Jianzhong; Luo, Fei

    2016-06-01

    Cell adhesion is an important property of biomaterials used in selective cell retention (SCR) technology, which fabricates bone grafts rapidly in clinical settings. This could be improved by physical and biologic manipulations. To facilitate retention of the cells on the scaffold, especially osteoprogenitors from bone marrow in the convenient SCR procedure, a lysine-cyclic RGD (LcRGD) peptide was here designed to coordinate positively charged amino acids and the RGD sequence to enhance the adhesion performance of the scaffold. Demineralized bone matrix (DBM) is an important therapeutic resource, but its cell adhesion ability and osteoinductive capacity are low because of its processing. These capabilities can be increased to enhance the performance of DBM when used in SCR technology. Here, LcRGD peptide was used to modify DBM and produce a DBM/LcRGD composite. This composite exhibited enhanced adhesion performance on cultured human bone marrow-derived mesenchymal stem cells and retained more osteoprogenitors from bone marrow than other materials did. The DBM/LcRGD composite displayed a preferable osteoinduction in vitro and osteogenic capacity in vivo. Thus, LcRGD peptide as a commendable modifier of DBM applied in SCR technology can improve bone transplantation. PMID:27154386

  16. Gene coevolution and regulation lock cyclic plant defence peptides to their targets.

    Gilding, Edward K; Jackson, Mark A; Poth, Aaron G; Henriques, Sónia Troeira; Prentis, Peter J; Mahatmanto, Tunjung; Craik, David J

    2016-04-01

    Plants have evolved many strategies to protect themselves from attack, including peptide toxins that are ribosomally synthesized and thus adaptable directly by genetic polymorphisms. Certain toxins in Clitoria ternatea (butterfly pea) are cyclic cystine-knot peptides of c. 30 residues, called cyclotides, which have co-opted the plant's albumin-1 gene family for their production. How butterfly pea albumin-1 genes were commandeered and how these cyclotides are utilized in defence remain unclear. The role of cyclotides in host plant ecology and biotechnological applications requires exploration. We characterized the sequence diversity and expression dynamics of precursor and processing proteins implicated in butterfly pea cyclotide biosynthesis by expression profiling through RNA-sequencing (RNA-seq). Peptide-enriched extracts from various organs were tested for activity against insect-like membranes and the model nematode Caenorhabditis elegans. We found that the evolution and deployment of cyclotides involved their diversification to exhibit different chemical properties and expression between organs facing different defensive challenges. Cyclotide-enriched fractions from soil-contacting organs were effective at killing nematodes, whereas similar enriched fractions from aerial organs contained cyclotides that exhibited stronger interactions with insect-like membrane lipids. Cyclotides are employed as versatile and combinatorial mediators of defence in C. ternatea and have specialized to affect different classes of attacking organisms. PMID:26668107

  17. Effect of chelator conjugation level and injection dose on tumor and organ uptake of 111In-labeled MORAb-009, an anti-mesothelin antibody

    Introduction: Radiolabeling of a monoclonal antibody (mAb) with a metallic radionuclide requires the conjugation of a bifunctional chelator to the mAb. The conjugation, however, can alter the physical and immunological properties of the mAb, consequently affecting its tumor-targeting pharmacokinetics. In this study, we investigated the effect of the amount of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriamine-pentaacetic acid (CHX-A″) conjugated to MORAb-009, a mAb directed against mesothelin, and the effect of MORAb dose on the biodistribution of 111In-labeled MORAb-009. Methods: We used nude mice bearing the A431/K5 tumor as a mesothelin-positive tumor model and the A431 tumor as a mesothelin-negative control. To find the optimal level of CHX-A″ conjugation, CHX-A″-MORAb-009 conjugates with 2.4, 3.5 and 5.5 CHX-A″ molecules were investigated. To investigate the effect of injected MORAb-009 dose on neutralizing the shed mesothelin in the circulation, biodistribution studies were performed after the intravenous co-injection of 111In-labeled MORAb-009 (2.4 CHX-A″/MORAb-009) with three different doses: 0.2, 2 and 30 μg of MORAb-009. Results: The tumor uptake in A431/K5 tumor was four times higher than that in A431 tumor, indicating that the tumor uptake in A431/K5 was mesothelin mediated. The conjugate with 5.5 CHX-A″ showed a lower isoelectric point (pI) and lower immunoreactivity (IR) than the 2.4 CHX-A″ conjugate. These differences were reflected in the biodistribution of the 111In label. The 111In-labeled MORAb-009 conjugated with 2.4 CHX-A″ produced higher tumor uptake and lower liver and spleen uptakes than the 5.5 CHX-A″ conjugate. The biodistribution studies also revealed that the tumor uptake was significantly affected by the injected MORAb-009 dose and tumor size. The 30-μg dose produced higher tumor uptake than the 0.2- and 2-μg doses, whereas the 30-μg dose produced lower liver and spleen uptakes than the 0.2-μg dose

  18. Stereochemistry Balances Cell Permeability and Solubility in the Naturally Derived Phepropeptin Cyclic Peptides.

    Schwochert, Joshua; Lao, Yongtong; Pye, Cameron R; Naylor, Matthew R; Desai, Prashant V; Gonzalez Valcarcel, Isabel C; Barrett, Jaclyn A; Sawada, Geri; Blanco, Maria-Jesus; Lokey, R Scott

    2016-08-11

    Cyclic peptide (CP) natural products provide useful model systems for mapping "beyond-Rule-of-5" (bRo5) space. We identified the phepropeptins as natural product CPs with potential cell permeability. Synthesis of the phepropeptins and epimeric analogues revealed much more rapid cellular permeability for the natural stereochemical pattern. Despite being more cell permeable, the natural compounds exhibited similar aqueous solubility as the corresponding epimers, a phenomenon explained by solvent-dependent conformational flexibility among the natural compounds. When analyzing the polarity of the solution structures we found that neither the number of hydrogen bonds nor the total polar surface area accurately represents the solvation energies of the high and low dielectric conformations. This work adds to a growing number of natural CPs whose solvent-dependent conformational behavior allows for a balance between aqueous solubility and cell permeability, highlighting structural flexibility as an important consideration in the design of molecules in bRo5 chemical space. PMID:27563399

  19. Isolation and characterization of Pseudallescheria boydii secreted cyclic peptide – the potential marker in diagnostics of fungl infection

    Sklenář, Jan; Šulc, Miroslav; Žabka, Martin; Havlíček, Vladimír

    Ustron : Verlag, 2006, s. 24-24. [ Informal Meeting on Mass Spectrometry /24./. Ustroń (PL), 14.05.2006-18.05.2006] R&D Projects: GA MŠk LC545 Institutional research plan: CEZ:AV0Z50200510 Keywords : cyclic peptide * Pseudalleschria boydii Subject RIV: EE - Microbiology, Virology

  20. Profiling anti-cyclic citrullinated peptide antibodies in patients with juvenile idiopathic arthritis

    Tebo Anne E

    2012-08-01

    Full Text Available Abstract Background Anti-citrullinated protein/peptide antibodies (ACPA, have high specificity for rheumatoid arthritis (RA. Some children with juvenile idiopathic arthritis (JIA, phenotypically resemble RA and test positive for rheumatoid factor (RF a characteristic biomarker of RA. We investigated the prevalence of ACPA and its relationship to other serologic markers associated with RA in a well-characterized JIA cohort. Methods Cases were 334 children with JIA, 30 of whom had RF + polyarticular JIA. Sera from all cases and 50 healthy pediatric controls were investigated by ELISA at a single time point for anti-cyclic citrullinated peptide (anti-CCP IgG, RF IgM, IgA and IgG, anti-RA33 IgG, and antinuclear antibodies (ANA. Comparisons between cases and controls were made using Chi-square or Fisher exact tests and T-tests. Results The prevalence of RF was 8% among controls, and 12% among cases (ns. The prevalence of ACPA was 2% in controls and 14.3% in cases (OR 8.2, p Conclusions ACPAs are detectable in 14% of children with JIA. Children with positive ACPA but negative RF are frequent, and may define a distinct subset of children with JIA. ACPA testing should be included in the classification of JIA.

  1. Solvent-induced conformational changes in cyclic peptides: a vibrational circular dichroism study.

    Merten, Christian; Li, Fee; Bravo-Rodriguez, Kenny; Sanchez-Garcia, Elsa; Xu, Yunjie; Sander, Wolfram

    2014-03-28

    The three-dimensional structure of a peptide is strongly influenced by its solvent environment. In the present study, we study three cyclic tetrapeptides which serve as model peptides for β-turns. They are of the general structure cyclo(Boc-Cys-Pro-X-Cys-OMe) with the amino acid X being either glycine (1), or L- or D-leucine (L- or D-2). Using vibrational circular dichroism (VCD) spectroscopy, we confirm previous NMR results which showed that D-2 adopts predominantly a βII turn structure in apolar and polar solvents. Our results for L-2 indicate a preference for a βI structure over βII. With increasing solvent polarity, the preference for 1 is shifted from βII towards βI. This conformational change goes along with the breaking of an intramolecular hydrogen bond which stabilizes the βII conformation. Instead, a hydrogen bond with a solvent molecule can stabilize the βI turn conformation. PMID:24513908

  2. Investigating surface topology and cyclic-RGD peptide functionalization on vascular endothelialization.

    McNichols, Colton; Wilkins, Justin; Kubota, Atsutoshi; Shiu, Yan T; Aouadi, Samir M; Kohli, Punit

    2014-02-01

    The advantages of endothelialization of a stent surface in comparison with the bare metal and drug-eluting stents used today include reduced late-stent restenosis and in-stent thrombosis. In this article, we study the effect of surface topology and functionalization of tantalum (Ta) with cyclic-(arginine-glycine-aspartic acid-d-phenylalanine-lysine) (cRGDfK) on the attachment, spreading, and growth of vascular endothelial cells. Self-assembled nanodimpling on Ta surfaces was performed using a one-step electropolishing technique. Next, cRGDfK was covalently bonded onto the surface using silane chemistry. Our results suggest that nanotexturing alone was sufficient to enhance cell spreading, but the combination of a nanodimpled surfaces along with the cRGDfK peptide may produce a better endothelialization coating on the surface in terms of higher cell density, better cell spreading, and more cell-cell interactions, when compared to using cRGDfK peptide functionalization alone or nanotexturing alone. We believe that future research should look into how to implement both modifications (topographic and chemical modifications) to optimize the stent surface for endothelialization. PMID:23505215

  3. IRMPD Spectroscopy: Evidence of Hydrogen Bonding in the Gas Phase Conformations of Lasso Peptides and their Branched-Cyclic Topoisomers.

    Jeanne Dit Fouque, Kevin; Lavanant, Hélène; Zirah, Séverine; Steinmetz, Vincent; Rebuffat, Sylvie; Maître, Philippe; Afonso, Carlos

    2016-06-01

    Lasso peptides are natural products characterized by a mechanically interlocked topology. The conformation of lasso peptides has been probed in the gas phase using ion mobility-mass spectrometry (IM-MS) which showed differences in the lasso and their unthreaded branched-cyclic topoisomers depending on the ion charge states. To further characterize the evolution of gas phase conformations as a function of the charge state and to assess associated changes in the hydrogen bond network, infrared multiple photon dissociation (IRMPD) action spectroscopy was carried out on two representative lasso peptides, microcin J25 (MccJ25) and capistruin, and their branched-cyclic topoisomers. For the branched-cyclic topoisomers, spectroscopic evidence of a disruption of neutral hydrogen bonds were found when comparing the 3+ and 4+ charge states. In contrast, for the lasso peptides, the IRMPD spectra were found to be similar for the two charge states, suggesting very little difference in gas phase conformations upon addition of a proton. The IRMPD data were thus found consistent and complementary to IM-MS, confirming the stable and compact structure of lasso peptides in the gas phase. PMID:27171649

  4. Use of autologous /sup 111/In-labelled platelets and scintigraphy to illustrate enhanced platelet activity during erection in the chacma baboon

    Dormehl, I.C.; Du Plessis, M.; Maree, M.; Bornman, M.S.; Du Plessis, D.J.

    1984-12-01

    The demonstration of thrombelastographic hypercoagulability in the penile blood during erection, and the accompanying deposition of fibrin onto the endothelial layer of the deep penile artery and trabecular surface inspired this investigation of the possible role that platelets might play in the process. The bloodpooling pattern in the penis during and after erection from electro-stimulation was studied in 9 male adult baboons (Papio ursinus) using in vivo sup(99m)Tc-labelled red blood cells and scintigraphy. Platelet activity was similarly investigated after administering autologous /sup 111/In-labelled platelets to the baboons. The results indicate an enhanced platelet concentration with respect to blood-pooling during erection, and an entrapment of platelets after erection.

  5. The use of autologous 111In-labelled platelets and scintigraphy to illustrate enhanced platelet activity during erection in the chacma baboon

    The demonstration of thrombelastographic hypercoagulability in the penile blood during erection, and the accompanying deposition of fibrin onto the endothelial layer of the deep penile artery and trabecular surface inspired this investigation of the possible role that platelets might play in the process. The bloodpooling pattern in the penis during and after erection from electro-stimulation was studied in 9 male adult baboons (Papio ursinus) using in vivo sup(99m)Tc-labelled red blood cells and scintigraphy. Platelet activity was similarly investigated after administering autologous 111In-labelled platelets to the baboons. The results indicate an enhanced platelet concentration with respect to blood-pooling during erection, and an entrapment of platelets after erection. (orig.)

  6. Immunization with synthetic peptides containing epitopes of the class 1 outer-membrane protein of Neisseria meningitidis: production of bactericidal antibodies on immunization with a cyclic peptide.

    Christodoulides, M; McGuinness, B T; Heckels, J E

    1993-08-01

    The class 1 outer-membrane protein of Neisseria meningitidis is the target for subtype-specific, bactericidal monoclonal antibodies (mAbs). The epitopes recognized by these antibodies have been mapped previously to linear peptides corresponding to the sequences thought to be exposed at the apices of surface-exposed loops of the protein. In this work several synthetic peptides containing the subtype Pl.16b epitope have been synthetized with the aim of inducing a polyclonal immune response resembling the reactivity of the mAbs. Initially, peptides of 9 and 15 amino acid residues were synthesized and used for immunization after coupling to a carrier protein. The reactivity of the resulting antisera, with synthetic linear decapeptides, resembled that seen in previous epitope mapping experiments with the protective mAbs. However, despite the induction of antibodies having the desired specificity, the antisera reacted poorly with the native protein in outer membranes, and were non-bactericidal. A 36mer peptide, consisting of the entire surface-exposed loop 4 of the class 1 protein was then synthesized and used for immunization as (i) free peptide, (ii) peptide coupled to carrier and (iii) peptide subjected to cyclization, in an attempt to restrict it to conformations that might more closely resemble the native loop structure. In contrast to antisera raised against linear peptides, antibodies raised by immunization with the 36mer cyclic peptide, did not react with linear peptides recognized by the mAbs, but instead appeared to recognize conformational determinants. This antiserum promoted complement-mediated bactericidal killing of the homologous meningococcal strain, demonstrating the potential of synthetic peptide immunogens for inducing a protective immune response against group B meningococci. PMID:7691983

  7. Cryogenic Spectroscopy and Quantum Molecular Dynamics Determine the Structure of Cyclic Intermediates Involved in Peptide Sequence Scrambling.

    Aseev, Oleg; Perez, Marta A S; Rothlisberger, Ursula; Rizzo, Thomas R

    2015-07-01

    Collision-induced dissociation (CID) is a key technique used in mass spectrometry-based peptide sequencing. Collisionally activated peptides undergo statistical dissociation, forming a series of backbone fragment ions that reflect their amino acid (AA) sequence. Some of these fragments may experience a "head-to-tail" cyclization, which after proton migration, can lead to the cyclic structure opening in a different place than the initially formed bond. This process leads to AA sequence scrambling that may hinder sequencing of the initial peptide. Here we combine cryogenic ion spectroscopy and ab initio molecular dynamics simulations to isolate and characterize the precise structures of key intermediates in the scrambling process. The most stable peptide fragments show intriguing symmetric cyclic structures in which the proton is situated on a C2 symmetry axis and forms exceptionally short H-bonds (1.20 Å) with two backbone oxygens. Other nonsymmetric cyclic structures also exist, one of which is protonated on the amide nitrogen, where ring opening is likely to occur. PMID:26266729

  8. Truncated atrial natriuretic peptide (ANP) analogs: relationship between receptor binding and cyclic GMP accumulation

    The authors have shown that cultured bovine aortic smooth muscle (BASM) cells contain high affinity receptor sites for the ANP, auriculin (ANP(4-28)). Furthermore, ANP(4-28) causes cyclic GMP (cGMP) levels to increase in BASM. In the present study, the authors synthesized a series of NH2 and/or COOH truncated ANP(4-28) analogs and examined their ability to compete for 125I-ANP(4-28) binding to BASM and increase cGMP levels. ANP-mediated cGMP responses were reduced when amino acids were deleted from the NH2 and/or COOH termini of ANP(4-28). Removal of the NH2 terminal R, R-S, or R-S-S residues resulted in a 10X decrease in potency for cGMP stimulation. Deletion of the COOH terminal R-Y and F-R-Y residues resulted in a marked decline in potency. ANP's lacking the F-R-Y tripeptide were nearly inactive in stimulating cGMP accumulation. In contrast to the cGMP effects, NH2 and/or COOH truncations of ANP(4-28) did not alter apparent receptor binding affinities (Ki(app)). All of these peptide analogs exhibited Ki(app)'s of 1-5 nM. Furthermore, peptides that bound effectively and failed to elicit cGMP responses did not antagonize ANP(4-28)-mediated cGMP increases. These binding and functional data suggest the presence of a single class of ANP receptors on BASM is insufficient to explain the actions of ANP's in these cells

  9. Structural, nanomechanical, and computational characterization of D,L-cyclic peptide assemblies.

    Rubin, Daniel J; Amini, Shahrouz; Zhou, Feng; Su, Haibin; Miserez, Ali; Joshi, Neel S

    2015-03-24

    The rigid geometry and tunable chemistry of D,L-cyclic peptides makes them an intriguing building-block for the rational design of nano- and microscale hierarchically structured materials. Herein, we utilize a combination of electron microscopy, nanomechanical characterization including depth sensing-based bending experiments, and molecular modeling methods to obtain the structural and mechanical characteristics of cyclo-[(Gln-D-Leu)4] (QL4) assemblies. QL4 monomers assemble to form large, rod-like structures with diameters up to 2 μm and lengths of tens to hundreds of micrometers. Image analysis suggests that large assemblies are hierarchically organized from individual tubes that undergo bundling to form larger structures. With an elastic modulus of 11.3 ± 3.3 GPa, hardness of 387 ± 136 MPa and strength (bending) of 98 ± 19 MPa the peptide crystals are among the most robust known proteinaceous micro- and nanofibers. The measured bending modulus of micron-scale fibrils (10.5 ± 0.9 GPa) is in the same range as the Young's modulus measured by nanoindentation indicating that the robust nanoscale network from which the assembly derives its properties is preserved at larger length-scales. Materials selection charts are used to demonstrate the particularly robust properties of QL4 including its specific flexural modulus in which it outperforms a number of biological proteinaceous and nonproteinaceous materials including collagen and enamel. The facile synthesis, high modulus, and low density of QL4 fibers indicate that they may find utility as a filler material in a variety of high efficiency, biocompatible composite materials. PMID:25757883

  10. Dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes.

    Li, Rui; Fan, Jianfen; Li, Hui; Yan, Xiliang; Yu, Yi

    2015-07-01

    Classical molecular dynamics simulations have been performed to investigate the dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes (CPNTs) with various radii, i.e., 8×(WL¯)n=3,4,5/POPE. The results show that ethanol molecules spontaneously fill the octa- and deca-CPNTs, but not the hexa-CPNT. In the octa-CPNT, ethanol molecules are trapped at individual gaps with their carbon skeletons perpendicular to the tube axis and hydroxyl groups towards the tube wall, forming a broken single-file chain. As the channel radius increases, ethanol molecules inside the deca-CPNT tend to form a tubular layer and the hydroxyl groups mainly stretch towards the tube axis. Computations of diffusion coefficients indicate that ethanol molecules in the octa-CPNT nearly lost their diffusion abilities, while those in the deca-CPNT diffuse as 4.5 times as in a (8, 8) carbon nanotube with a similar tube diameter. The osmotic and diffusion permeabilities (pf and pd, respectively) of the octa- and deca-CPNTs transporting ethanol were deduced for the first time. The distributions of the gauche and trans conformers of ethanol molecules in two CPNTs are quite similar, both with approximately 57% gauche conformers. The non-bonded interactions of channel ethanol with a CPNT wall and surrounding ethanol were explored. The potential of mean force elucidates the mechanism underlying the transporting characteristics of channel ethanol in a transmembrane CPNT. PMID:26156492

  11. Transport properties of simple organic molecules in a transmembrane cyclic peptide nanotube.

    Xu, Jian; Fan, Jian Fen; Zhang, Ming Ming; Weng, Pei Pei; Lin, Hui Fang

    2016-05-01

    Multiple molecular dynamics simulations have been performed to explore the transport properties of single methane, methanol, and ethanol molecules through the water-filled transmembrane cyclic peptide nanotube (CPNT) of 8 × (WL)₄-POPE, as well as the potential application of this CPNT in the separation of an alcohol/water mixture. Molecular size and hydrophilicity/hydrophobicity were found to significantly influence molecular diffusion behavior in the channel. Methane and ethanol display more explicit distributions in midplane regions, while methanol mainly occurs in α-plane zones. Methane and ethanol drift faster near an α-plane zone, whereas methanol diffuses uniformly throughout the whole transmembrane region. The dipole orientation of channel methanol is significantly affected by the bare carbonyl groups at the tube mouths and flips mainly in gap 4, whereas the rotation of ethanol is blocked. Ball-shaped hydrophobic methane experiences more flips in gap 4. The PMF (potential of mean force) profiles of the three organic molecules disclose their different diffusion behaviors in the CPNT. Amphiphilic alcohols are able to form direct H-bonds with channel water and the tube. Both single and double water bridges with the tube were observed in the methanol and ethanol systems. The different adsorption behaviors of the alcohols and water in the dehydrated CPNT may lead to the potential application of the CPNT as a means of separating alcohols from water. PMID:27083567

  12. A Threshold-Minimization Scheme for Exploring the Energy Landscape of Biomolecules: Application to a Cyclic Peptide and a Disaccharide.

    Neelamraju, Sridhar; Johnston, Roy L; Schön, J Christian

    2016-05-10

    We present a scheme, called the threshold-minimization method, for globally exploring the energy landscapes of small systems of biomolecular interest where typical exploration moves always require a certain degree of subsequent structural relaxation in order to be efficient, e.g., systems containing small or large circular carbon chains such as cyclic peptides or carbohydrates. We show that using this threshold-minimization method we can not only reproduce the global minimum and relevant local minima but also overcome energetic barriers associated with different types of isomerism for the example of a cyclic peptide, cyclo-(Gly)4. We then apply the new method to the disaccharide α-d-glucopyranose-1-2-β-d-fructofuranose, report energetically preferred configurations and barriers to boat-chair isomerization in the glucopyranosyl ring, and discuss the energy landscape. PMID:27049524

  13. Influence of an aliphatic linker between DOTA and synthetic Z{sub HER2:342} Affibody molecule on targeting properties of the {sup 111}In-labeled conjugate

    Tolmachev, Vladimir, E-mail: vladimir.tolmachev@bms.uu.se [Division of Biomedical Radiation Sciences, Department of Radiology, Oncology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden); Feldwisch, Joachim [Division of Biomedical Radiation Sciences, Department of Radiology, Oncology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden); Affibody AB, SE-112 51, Stockholm (Sweden); Lindborg, Malin; Baastrup, Barbro [Affibody AB, SE-112 51, Stockholm (Sweden); Sandstroem, Mattias [Hospital Physics, Department of Oncology, Uppsala University Hospital, Uppsala (Sweden); Orlova, Anna [Division of Biomedical Radiation Sciences, Department of Radiology, Oncology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden)

    2011-07-15

    Introduction: Affibody molecules are small ({approx}6.5 kDa) scaffold proteins suitable for radionuclide imaging of tumor-associated molecular targets. Site-specific labeling of Affibody molecules made by peptide synthesis can be achieved by coupling a chelator to N-terminus in the last synthesis step. The goal of this study was to evaluate the influence of a 6-aminohexanoic linker between DOTA and Z{sub HER2:342} on targeting properties of {sup 111}In-labeled conjugate. Methods: A DOTA-conjugated 6-aminohexanoic linker-containing variant of Z{sub HER2:342} (ABY-003) was produced by peptide synthesis, and the in vitro binding affinity, specificity and cellular processing were evaluated. The biodistribution of {sup 111}In-ABY-003 in normal mice was compared to {sup 111}In-ABY-002 (DOTA-Z{sub HER2:342-pep2}) lacking the linker. Tumor-targeting properties of {sup 111}In-ABY-003 were evaluated in mice bearing HER2-expressing xenografts. Results: The dissociation constant of ABY-003 was in the low picomolar range, slightly higher than for ABY-002. {sup 111}In-ABY-003 bound specifically to HER2-expressing cells in vitro. The cellular retention was efficient but slightly worse than for {sup 111}In-ABY-002. In normal mice, the clearance of {sup 111}In-ABY-003 from blood and other tissues was slightly but significantly faster compared to {sup 111}In-ABY-002. Targeting of HER2-expressing xenografts by {sup 111}In-ABY-003 was receptor-specific. Due to faster clearance, the tumor-to-blood ratio for {sup 111}In-ABY-003 at 4 h postinjection was improved compared to {sup 111}In-ABY-002. The capacity of {sup 111}In-ABY-003 to visualize HER2-expressing tumors was confirmed by gamma camera imaging. Conclusions: A 6-aminohexanoic linker between the DOTA chelator and N-terminus of synthetic Z{sub HER2:342} had a measurable effect on affinity, cellular retention of radioactivity and blood clearance. The linker might be used for modulation of targeting properties of Affibody molecules.

  14. Development of a prosaposin-derived therapeutic cyclic peptide that targets ovarian cancer via the tumor microenvironment.

    Wang, Suming; Blois, Anna; El Rayes, Tina; Liu, Joyce F; Hirsch, Michelle S; Gravdal, Karsten; Palakurthi, Sangeetha; Bielenberg, Diane R; Akslen, Lars A; Drapkin, Ronny; Mittal, Vivek; Watnick, Randolph S

    2016-03-01

    The vast majority of ovarian cancer-related deaths are caused by metastatic dissemination of tumor cells, resulting in subsequent organ failure. However, despite our increased understanding of the physiological processes involved in tumor metastasis, there are no clinically approved drugs that have made a major impact in increasing the overall survival of patients with advanced, metastatic ovarian cancer. We identified prosaposin (psap) as a potent inhibitor of tumor metastasis, which acts via stimulation of p53 and the antitumorigenic protein thrombospondin-1 (TSP-1) in bone marrow-derived cells that are recruited to metastatic sites. We report that more than 97% of human serous ovarian tumors tested express CD36, the receptor that mediates the proapoptotic activity of TSP-1. Accordingly, we sought to determine whether a peptide derived from psap would be effective in treating this form of ovarian cancer. To that end, we developed a cyclic peptide with drug-like properties derived from the active sequence in psap. The cyclic psap peptide promoted tumor regression in a patient-derived tumor xenograft model of metastatic ovarian cancer. Thus, we hypothesize that a therapeutic agent based on this psap peptide would have efficacy in treating patients with metastatic ovarian cancer. PMID:26962158

  15. STAT1, STAT3 and p38MAPK are involved in the apoptotic effect induced by a chimeric cyclic interferon-{alpha}2b peptide

    Blank, Viviana C.; Pena, Clara [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina); Roguin, Leonor P., E-mail: rvroguin@qb.ffyb.uba.ar [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina)

    2010-02-15

    In the search of mimetic peptides of the interferon-{alpha}2b molecule (IFN-{alpha}2b), we have previously designed and synthesized a chimeric cyclic peptide of the IFN-{alpha}2b that inhibits WISH cell proliferation by inducing an apoptotic response. Here, we first studied the ability of this peptide to activate intracellular signaling pathways and then evaluated the participation of some signals in the induction of apoptosis. Stimulation of WISH cells with the cyclic peptide showed tyrosine phosphorylation of Jak1 and Tyk2 kinases, tyrosine and serine phosphorylation of STAT1 and STAT3 transcription factors and activation of p38 MAPK pathway, although phosphorylation levels or kinetics were in some conditions different to those obtained under IFN-{alpha}2b stimulus. JNK and p44/42 pathways were not activated by the peptide in WISH cells. We also showed that STAT1 and STAT3 downregulation by RNA interference decreased the antiproliferative activity and the amount of apoptotic cells induced by the peptide. Pharmacological inhibition of p38 MAPK also reduced the peptide growth inhibitory activity and the apoptotic effect. Thus, we demonstrated that the cyclic peptide regulates WISH cell proliferation through the activation of Jak/STAT signaling pathway. In addition, our results indicate that p38 MAPK may also be involved in cell growth regulation. This study suggests that STAT1, STAT3 and p38 MAPK would be mediating the antitumor and apoptotic response triggered by the cyclic peptide in WISH cells.

  16. Synthesis of linear and cyclic peptide-PEG-lipids for stabilization and targeting of cationic liposome-DNA complexes.

    Ewert, Kai K; Kotamraju, Venkata Ramana; Majzoub, Ramsey N; Steffes, Victoria M; Wonder, Emily A; Teesalu, Tambet; Ruoslahti, Erkki; Safinya, Cyrus R

    2016-03-15

    Because nucleic acids (NAs) have immense potential value as therapeutics, the development of safe and effective synthetic NA vectors continues to attract much attention. In vivo applications of NA vectors require stabilized, nanometer-scale particles, but the commonly used approaches of steric stabilization with a polymer coat (e.g., PEGylation; PEG=poly(ethylene glycol)) interfere with attachment to cells, uptake, and endosomal escape. Conjugation of peptides to PEG-lipids can improve cell attachment and uptake for cationic liposome-DNA (CL-DNA) complexes. We present several synthetic approaches to peptide-PEG-lipids and discuss their merits and drawbacks. A lipid-PEG-amine building block served as the common key intermediate in all synthetic routes. Assembling the entire peptide-PEG-lipid by manual solid phase peptide synthesis (employing a lipid-PEG-carboxylic acid) allowed gram-scale synthesis but is mostly applicable to linear peptides connected via their N-terminus. Conjugation via thiol-maleimide or strain-promoted (copper-free) azide-alkyne cycloaddition chemistry is highly amenable to on-demand preparation of peptide-PEG-lipids, and the appropriate PEG-lipid precursors are available in a single chemical step from the lipid-PEG-amine building block. Azide-alkyne cycloaddition is especially suitable for disulfide-bridged peptides such as iRGD (cyclic CRGDKGPDC). Added at 10 mol% of a cationic/neutral lipid mixture, the peptide-PEG-lipids stabilize the size of CL-DNA complexes. They also affect cell attachment and uptake of nanoparticles in a peptide-dependent manner, thereby providing a platform for preparing stabilized, affinity-targeted CL-DNA nanoparticles. PMID:26874401

  17. In vitro detection of mdr1 mRNA in murine leukemia cells with {sup 111}In-labeled oligonucleotide

    Bai Jingming; Yokoyama, Kunihiko; Kinuya, Seigo; Michigishi, Takatoshi; Tonami, Norihisa [Kanazawa University Graduate School of Medical Sciences, Department of Biotracer Medicine (Nuclear Medicine), Kanazawa (Japan); Shiba, Kazuhiro [Kanazawa University, Radioisotope Center, Kanazawa (Japan); Matsushita, Ryo [Kanazawa University, Laboratory for Development of Medicine, Faculty of Pharmaceutical Sciences, Kanazawa (Japan); Nomura, Masaaki [Kanazawa University Hospital, Hospital Pharmacy, Kanazawa (Japan)

    2004-11-01

    The feasibility of intracellular mdr1 mRNA expression detection with radiolabeled antisense oligonucleotide (ODN) was investigated in the murine leukemia cell line, P388/S, and its subclonal, adriamycin-resistant cell line, P388/R. The expression level of mdr1 mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Existence of the multidrug resistance (MDR) phenomenon was assessed via cellular uptake of {sup 99m}Tc-sestamibi (MIBI), a known substrate for P-glycoprotein. A 15-mer phosphorothioate antisense ODN complementary to the sequences located at -1 to 14 of mdr1 mRNA and its corresponding sense ODN were conjugated with the cyclic anhydride of diethylene triamine penta-acetic acid (cDTPA) via an amino group linked to the terminal phosphate at the 5' end at pH 8-9. The DTPA-ODN complexes at concentrations of 0.1-17.4 {mu}Mwere reacted with {sup 111}InCl{sub 3} at pH 5 for 1 h. The hybridization affinity of labeled ODN was evaluated with size-exclusion high-performance liquid chromatography following incubation with the complementary sequence. Cellular uptake of labeled ODN was examined in vitro. Furthermore, enhancing effects of synthetic lipid carriers (Transfast) on transmembrane delivery of ODN were assessed. P388/R cells displayed intense mdr1 mRNA expression in comparison with P388/S cells. {sup 99m}Tc-MIBI uptake in P388/S cells was higher than that in P388/R cells. Specific radioactivity up to 1,634 MBq/nmol was achieved via elevation of added radioactivity relative to ODN molar amount. The hybridization affinity of antisense {sup 111}In-ODN was preserved at approximately 85% irrespective of specific activity. Cellular uptake of antisense {sup 111}In-ODN did not differ from that of sense {sup 111}In-ODN in either P388/S cells or P388/R cells. However, lipid carrier incorporation significantly increased transmembrane delivery of {sup 111}In-ODN; moreover, specific uptake of antisense {sup 111}In-ODN was demonstrated in P388/R

  18. Improved immunoscintigraphy by subcutaneous injection of sup(99m)Tc or 111In labelled F(ab')2 fragments of an anti-melanoma monoclonal antibody

    Technetium-99m and/or 111In labelled F(ab')2 fragments of a melanoma associated MoAb 225.28S were injected i.v. in 80 patients affected by stage I to IV malignant melanoma. 75% of metastatic lesions already documented by other methods were detected by immunoscintigraphy, which was also capable of detecting a certain number of unknown metastases. The authors observed a lower percentage of positive scans in liver, lung and skin because of the poor tumour to background ratio. In some patients, subcutaneous (s.c.) injection allowed visualization documented metastases undetected by i.v. administration. An equal amount on non-specific F(ab')2 fragments (MoAb 4C4) injected s.c. as a negative control showed no positive scans. Clinical studies and chromatographic patterns of patient serum samples suggest that the s.c. route of administration offers, with respect to the the i.v. route, the advantage of reducing vascular background and aspecific accumulation in liver, probably because of retention of possible contaminants by the lymphatic system. (author)

  19. Covalent attachment of cyclic TAT peptides to GFP results in protein delivery into live cells with immediate bioavailability.

    Nischan, Nicole; Herce, Henry D; Natale, Francesco; Bohlke, Nina; Budisa, Nediljko; Cardoso, M Cristina; Hackenberger, Christian P R

    2015-02-01

    The delivery of free molecules into the cytoplasm and nucleus by using arginine-rich cell-penetrating peptides (CPPs) has been limited to small cargoes, while large cargoes such as proteins are taken up and trapped in endocytic vesicles. Based on recent work, in which we showed that the transduction efficiency of arginine-rich CPPs can be greatly enhanced by cyclization, the aim was to use cyclic CPPs to transport full-length proteins, in this study green fluorescent protein (GFP), into the cytosol of living cells. Cyclic and linear CPP-GFP conjugates were obtained by using azido-functionalized CPPs and an alkyne-functionalized GFP. Our findings reveal that the cyclic-CPP-GFP conjugates are internalized into live cells with immediate bioavailability in the cytosol and the nucleus, whereas linear CPP analogues do not confer GFP transduction. This technology expands the application of cyclic CPPs to the efficient transport of functional full-length proteins into live cells. PMID:25521313

  20. Preparation of 90Y-labeled different cyclic RGD peptides and evaluation in nude mice bearing human glioma xenografts

    90Y-DTPA-Bz-NH-SA-c(KRGDf) and 90Y-DTPA-Bz-NH-c(ERGDf) were prepared, and their in vitro and in vivo properties were compared. ITLC and HPLC show that the labeling yields of both compounds are more than 99% under the optimal conditions(pH=5.5, reac- ting at 80 degree C for 20 min), and they are stable in vitro. The biodistribution in nude mice bearing human glioma xenografts reveals no significant difference between these two radiolabeled com- pounds on uptake for all of tissues at the experimental time points; and pretty good tumor targeting and in vivo stability; and two radiolabeled compounds are mainly excreted through kid- neys, partly excreted through hepatobiliary system. The experimental data demonstrate that both of cyclic KRGDf and cyclic ERGDf are suitable for the further development of polymerconjugated RGD peptide drugs. (authors)

  1. RHEUMATOID FACTOR AND ANTI-CYCLIC CITRULLINATED PEPTIDE ANTIBODIES IN PATIENTS WITH PSORIATIC ARTHRITIS

    V. V. Badokin

    2011-06-01

    Full Text Available Objective: to define the clinical value of rheumatoid factor (RF and anti-cyclic citrullinated peptide antibodies (anti-CCP in early psori- atic arthritis (PA. Subjects and methods. Fifty-six patients (32 females and 24 males with early PA with a mean duration of 12±6.7 months were studied. The examinees' age ranged from 18 to 76 years (mean age 44±15.5 years. Mean psoriasis duration was 12.5±2.2 years. RF IgM was determined using a high-sensitive nephelometric method on a BN Pro-Spec analyzer (Siemens, Germany and serum anti-CCP concentra- tions were measured by immunochemiluminescence on a COBAS e411 analyzer (Roche, Switzerland. Group 1 included 10 patients with anti-CCP and/or RF (a study group; Group 2 comprised 46 patients without anti-CCP and RF (a control group. Results. There was anti-CCP in 7 (12.5% of the patients with early PA, RF in 8 (14.3%, both of them in 5 (9%. The study group had a severer course of PA accompanied by polyarthritis, inflamed distal interphalangeal joints, axial arthritis, dactylitis, enthesitis, and, in some cases spondylitis and sacroiliitis. In groups 1 and 2, the number of tender joints was 17.6±4 and 10±1.5, respectively (p = 0.04; that of swollen ones, 12.6±1.5 and 7.0±1.1 (p = 0.02; DAS28 index, 5.9±1.7 and 4.5±1.5 (p = 0.02; ESR, 34.5±5.9 and 22±2.3 (p = 0.04, high-sensitive C reactive protein, 70±25.3 and 24.9±5.0 (p = 0.06; and Sharp ratio, 68.7±14.3 and 21.3±3.8 (p < 0.004. Conclusion. In patients with early PA, anti-CCP and RF were encountered with an approximately equal frequency; at the same time, they were associated with polyarthritis, high disease activity, and an erosive process. 

  2. Environmental risk factors differ between rheumatoid arthritis with and without auto-antibodies against cyclic citrullinated peptides

    Pedersen, Line Merete Blak; Jacobsen, Søren; Klarlund, Mette;

    2006-01-01

    The aim of this study was to evaluate new and previously hypothesised non-genetic risk factors for serologic subtypes of rheumatoid arthritis (RA) defined by the presence or absence of auto-antibodies to cyclic citrullinated peptides (CCP). In a national case-control study, we included 515 patien...... recently diagnosed with RA according to the American College of Rheumatology 1987 classification criteria and 769 gender- and age-matched population controls. Telephone interviews provided information about non-genetic exposures, and serum samples for patients were tested for anti...

  3. Novel targeted nuclear imaging agent for gastric cancer diagnosis: glucose-regulated protein 78 binding peptide-guided 111In-labeled polymeric micelles

    Cheng, Chun-Chia

    2013-01-01

    Chun-Chia Cheng,1,2,* Chiung-Fang Huang,3,4,* Ai-Sheng Ho,5 Cheng-Liang Peng,6 Chun-Chao Chang,7,8 Fu-Der Mai,1,9 Ling-Yun Chen,10 Tsai-Yueh Luo,2 Jungshan Chang1,11,121Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, 2Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan, 3School of Dental Technology, Taipei Medical University, Taipei, 4Division of Family and Operative Dentistry, Department of Dentistry, Taipei Medical University Hospital, Taipei, 5Di...

  4. Transmembrane delivery of anticancer drugs through self-assembly of cyclic peptide nanotubes

    Chen, Jian; Zhang, Bei; Xia, Fei; Xie, Yunchang; Jiang, Sifan; Su, Rui; Lu, Yi; Wu, Wei

    2016-03-01

    Breaking the natural barriers of cell membranes achieves fast entry of therapeutics, which leads to enhanced efficacy and helps overcome multiple drug resistance. Herein, transmembrane delivery of a series of small molecule anticancer drugs was achieved by the construction of artificial transmembrane nanochannels formed by self-assembly of cyclic peptide (cyclo[Gln-(d-Leu-Trp)4-d-Leu], CP) nanotubes (CPNTs) in the lipid bilayers. Our in vitro study in liposomes indicated that the transport of molecules with sizes smaller than 1.0 nm, which is the internal diameter of the CPNTs, could be significantly enhanced by CPNTs in a size-selective and dose-dependent manner. Facilitated uptake of 5-fluorouracil (5-FU) was also confirmed in the BEL7402 cell line. On the contrary, CPs could facilitate neither the transport across liposomal membranes nor the uptake by cell lines of cytarabine, a counterevidence drug with a size of 1.1 nm. CPs had a very weak anticancer efficacy, but could significantly reduce the IC50 of 5-FU in BEL7402, HeLa and S180 cell lines. Analysis by a q test revealed that a combination of 5-FU and CP had a synergistic effect in BEL7402 at all CP levels, in S180 at CP levels higher than 64 μg mL-1, but not in HeLa, where an additive effect was observed. Temporarily, intratumoral injection is believed to be the best way for CP administration. In vivo imaging using 125I radio-labelled CP confirmed that CPNPTs were completely localized in the tumor tissues, and translocation to other tissues was negligible. In vivo anticancer efficacy was studied in the grafted S180 solid tumor model in mice, and the results indicated that tumor growth was greatly inhibited by the combinatory use of 5-FU and CP, and a synergistic effect was observed at CP doses of 0.25 mg per kg bw. It is concluded that facilitated transmembrane delivery of anticancer drugs with sizes smaller than 1.0 nm was achieved, and the synergistic anticancer effect was confirmed both in cell lines

  5. 111In-labeled platelets: effects of heparin on uptake by venous thrombi and relationship to the activated partial thromboplastin time

    The goal of heparin therapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin therapy is unclear. To explore this relationship, we studied the effect of several heparin regimens on the accretion of 111In-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5. Platelet accretion by venous thrombi occurs within narrow limits of heparin effect as reflected by the APTT

  6. Screening of Commercial Cyclic Peptides as Inhibitor Envelope Protein Dengue Virus (DENV Through Molecular Docking and Molecular Dynamics

    U.S.F. Tambunan

    2013-01-01

    Full Text Available Dengue virus (DENV has spread throughout the world, especially in tropical climates. Effective treatment of DENV infection is not yet available although several candidate vaccines have been developed. Treatment at this time is only to reduce symptoms and reduce the risk of death. Therefore, antiviral treatment is much needed. Envelope protein is one of the structural proteins of DENV which is known and could be a target of antiviral inhibitors and plays a special role in the fusion process. The aim of this research is to screen the commercial cyclic peptides which are used as inhibitors of envelope protein DENV through molecular docking and molecular dynamics at 310 and 312 K. Screening of commercial cyclic peptides through molecular docking ligands obtained best 10 ligands then examined the interaction between hydrogen bonding and residue contacts of the cavity envelope protein and obtained best three ligands which could enter the cavity of envelope protein overall. The three ligands were predicted through the ADME-Tox and the best ligand obtained was BNP (7-32, porcine. The results of molecular dynamics simulations at 310 and 312 K revealed that ligand can maintain interaction with the cavity of the target.

  7. Tracer level radiochemistry to clinical dose preparation of 177Lu-labeled cyclic RGD peptide dimer

    Aim: Integrin αvβ3 plays a significant role in angiogenesis during tumor growth and metastasis, and is a receptor for the extracellular matrix proteins with the exposed arginine(R)-glycine(G)-aspartic acid(D) tripeptide sequence. The over-expression of integrin αvβ3 during tumor growth and metastasis presents an interesting molecular target for both early detection and treatment of rapidly growing solid tumors. Considering the advantages of 177Lu for targeted radiotherapy and enhanced tumor targeting capability of cyclic RGD peptide dimer, an attempt has been made to optimize the protocol for the preparation of clinical dose of 177Lu labeled DOTA-E[c(RGDfK)]2 (E = Glutamic acid, f = phenyl alanine, K = lysine) as a potential agent for targeted tumor therapy. Methods: 177Lu was produced by thermal neutron bombardment on enriched Lu2O3 (82% in 176Lu) target at a flux of 1 × 1014 n/cm2.s for 21 d. Therapeutic dose of 177Lu-DOTA-E[c(RGDfK)]2 (7.4 GBq) was prepared by adding the aqueous solution of the ligand and 177LuCl3 to 0.1 M NH4OAC buffer containing gentisic acid and incubating the reaction mixture at 90 °C for 30 min. The yield and radiochemical purity of the complex was determined by HPLC technique. Parameters, such as, ligand-to-metal ratio, pH of the reaction mixture, incubation time and temperature were varied using tracer quantity of 177Lu (37 MBq) in order to arrive at the optimized protocol for the preparation of clinical dose. Biological behavior of the radiotracer prepared was studied in C57/BL6 mice bearing melanoma tumors. Results: 177Lu was produced with a specific activity of 950 ± 50 GBq/mg (25.7 ± 1.4 Ci/mg) and radionuclidic purity of 99.98%. A careful optimization of several parameters showed that 177Lu-DOTA-E[c(RGDfK)]2 could be prepared with adequately high radiochemical purity using a ligand-to-metal ratio ∼ 2. Based on these studies therapeutic dose of the agent with 7.4 GBq of 177Lu was formulated in ∼ 63 GBq/μM specific

  8. Cyclic peptides identified by phage display are competitive inhibitors of the tRNA-dependent amidotransferase of Helicobacter pylori.

    Pham, Van Hau; Maaroufi, Halim; Levesque, Roger C; Lapointe, Jacques

    2016-05-01

    In Helicobacter pylori, the heterotrimeric tRNA-dependent amidotransferase (GatCAB) is essential for protein biosynthesis because it catalyzes the conversion of misacylated Glu-tRNA(Gln) and Asp-tRNA(Asn) into Gln-tRNA(Gln) and Asn-tRNA(Asn), respectively. In this study, we used a phage library to identify peptide inhibitors of GatCAB. A library displaying loop-constrained heptapeptides was used to screen for phages binding to the purified GatCAB. To optimize the probability of obtaining competitive inhibitors of GatCAB with respect to its substrate Glu-tRNA(Gln), we used that purified substrate in the biopanning process of the phage-display technique to elute phages bound to GatCAB at the third round of the biopanning process. Among the eluted phages, we identified several that encode cyclic peptides rich in Trp and Pro that inhibit H. pylori GatCAB in vitro. Peptides P10 and P9 were shown to be competitive inhibitors of GatCAB with respect to its substrate Glu-tRNA(Gln), with Ki values of 126 and 392μM, respectively. The docking models revealed that the Trp residues of these peptides form π-π stacking interactions with Tyr81 of the synthetase active site, as does the 3'-terminal A76 of tRNA, supporting their competitive behavior with respect to Glu-tRNA(Gln) in the transamidation reaction. These peptides can be used as scaffolds in the search for novel antibiotics against the pathogenic bacteria that require GatCAB for Gln-tRNA(Gln) and/or Asn-tRNA(Asn) formation. PMID:26976271

  9. Role of Calcitonin Gene-Related Peptide in Bone Repair after Cyclic Fatigue Loading

    Sample, Susannah J.; Hao, Zhengling; Wilson, Aliya P; Muir, Peter

    2011-01-01

    Background Calcitonin gene related peptide (CGRP) is a neuropeptide that is abundant in the sensory neurons which innervate bone. The effects of CGRP on isolated bone cells have been widely studied, and CGRP is currently considered to be an osteoanabolic peptide that has effects on both osteoclasts and osteoblasts. However, relatively little is known about the physiological role of CGRP in-vivo in the skeletal responses to bone loading, particularly fatigue loading. Methodology/Principal Find...

  10. Lasiocepsin, a novel cyclic antimicrobial peptide from the venom of eusocial bee Lasioglossum laticeps (Hymenoptera: Halictidae)

    Monincová, Lenka; Slaninová, Jiřina; Fučík, Vladimír; Hovorka, Oldřich; Voburka, Zdeněk; Bednárová, Lucie; Maloň, Petr; Štokrová, Jitka; Čeřovský, Václav

    2012-01-01

    Roč. 43, č. 2 (2012), s. 751-761. ISSN 0939-4451 R&D Projects: GA ČR GA203/08/0536; GA ČR GAP205/10/1276 Grant ostatní: GAUK(CZ) 33779266 Keywords : antimicrobial peptides * disulfide bridge * analogs * peptide synthesis * wild-bee venom * CD spectroscopy Subject RIV: CE - Biochemistry Impact factor: 3.914, year: 2012

  11. Improving Tumor Uptake and Pharmacokinetics of 64Cu-Labeled Cyclic RGD Peptide Dimers with Gly3 and PEG4 Linkers

    Shi, Jiyun; Kim, Young-Seung; Zhai, Shizhen; Liu, Zhaofei; Chen, Xiaoyuan; Liu, Shuang

    2009-01-01

    Radiolabeled cyclic RGD (Arg-Gly-Asp) peptides represent a new class of radiotracers with potential for the early tumor detection and non-invasive monitoring of tumor metastasis and therapeutic response in cancer patients. This report describes the synthesis of two cyclic RGD peptide dimer conjugates, DOTA-PEG4-E[PEG4-c(RGDfK)]2 (DOTA-3PEG4-dimer: DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid; PEG4 = 15-amino-4,7,10,13-tetraoxapentadecanoic acid) and DOTA-G3-E[G3-c(RGDfK)]2 ...

  12. Hydroxyl-radical-induced oxidation of cyclic dipeptides: Reactions of free peptide radicals and their peroxyl radicals

    In the course of this study investigations were carried out into the reactions of hydroxyl radicals and hydrogen atoms with cyclic dipeptides as well as the subsequent reactions of peptide radicals and their peroxyl radicals in aqueous solution. The radiolysis products formed in the absence and presence of oxygen or transient metal complexes were characterized and determined on a quantitative basis. The linking of information from product analyses to the kinetic data for transient species obtained by time-resolving UV/VIS and conductivity measurements (pulse radiolysis) as well as computer-assisted simulations of individual events during the reaction permitted an evaluation of the mechanisms underlying the various processes and an identification of interim products with short life-times, which did or did not belong to the group of radicals. Through the characterization of key reactions of radicals and peroxyl radicals of this substance class a major advance has been made towards a better understanding of the role of radicals in the peptide compound and the mechanisms involved in indirect radiation effects on long-chain peptides and proteins. (orig.)

  13. Radiolabelled peptides for oncological diagnosis

    Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

    2012-02-15

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

  14. A Cell-Based Approach for the Biosynthesis/Screening of Cyclic Peptide Libraries against Bacterial Toxins

    Camarero, J A; Kimura, R; Woo, Y; Cantor, J; Steenblock, E

    2007-10-24

    Available methods for developing and screening small drug-like molecules able to knockout toxins or pathogenic microorganisms have some limitations. In order to be useful, these new methods must provide high-throughput analysis and identify specific binders in a short period of time. To meet this need, we are developing an approach that uses living cells to generate libraries of small biomolecules, which are then screened inside the cell for activity. Our group is using this new, combined approach to find highly specific ligands capable of disabling anthrax Lethal Factor (LF) as proof of principle. Key to our approach is the development of a method for the biosynthesis of libraries of cyclic peptides, and an efficient screening process that can be carried out inside the cell.

  15. Translation of Structure-Activity Relationships from Cyclic Mixed Efficacy Opioid Peptides to Linear Analogues

    Anand, Jessica P.; Porter-Barrus, Vanessa R.; Waldschmidt, Helen V.; Yeomans, Larisa; Pogozheva, Irina D.; Traynor, John R.; Mosberg, Henry I.

    2014-01-01

    Most opioid analgesics used in the treatment of pain are mu opioid receptor (MOR) agonists. While effective, there are significant drawbacks to opioid use, including the development of tolerance and dependence. However, the co-administration of a MOR agonist with a delta opioid receptor (DOR) antagonist slows the development of MOR-related side effects, while maintaining analgesia. We have previously reported a series of cyclic mixed efficacy MOR agonist/DOR antagonist ligands. Here we descri...

  16. Effects of atrial and brain natriuretic peptides upon cyclic GMP levels, potassium transport, and receptor binding in rat astrocytes

    Beaumont, K.; Tan, P.K. (Univ. of California, San Diego, La Jolla (USA))

    1990-02-01

    The ability of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) to alter cyclic GMP levels and NaKCl cotransport in rat neocortical astrocytes was determined. At concentrations of 10(-9)-10(-6) M, rat ANP99-126 (rANF), rat ANP102-126 (auriculin B), and rat ANP103-126 (atriopeptin III) stimulated 6- to 100-fold increases in cyclic GMP levels. Porcine BNP (pBNP) and rat BNP (rBNP) were 20%-90% as effective as rANF over most of this concentration range, although 10(-6) M pBNP produced a greater effect than rANF. NaKCl cotransport as measured by bumetanide-sensitive 86Rb+ influx was not altered by exposure of astrocytes to 10(-6)M rANF, pBNP, or rBNP. Both pBNP and rBNP, as well as rat ANP103-123 (atriopeptin I) and des(gl18, ser19, gly20, leu21, gly22) ANF4-23-NH2 (C-ANF4-23) strongly competed for specific 125I-rANF binding sites in astrocyte membranes with affinities ranging from 0.03 to 0.4 nM, suggesting that virtually all binding sites measured at subnanomolar concentrations of 125I-rANF were of the ANP-C (ANF-R2) receptor subtype. These receptors are thought to serve a clearance function and may be linked to a guanylate cyclase activity that is chemically and pharmacologically distinct from that coupled to ANP-A (ANF-R1) receptors. ANP receptors on astrocytes may function in limiting the access of ANP and BNP to neurons involved in body fluid and cardiovascular regulation.

  17. Formation of multicellular tumor spheroids induced by cyclic RGD-peptides and use for anticancer drug testing in vitro.

    Akasov, Roman; Zaytseva-Zotova, Daria; Burov, Sergey; Leko, Maria; Dontenwill, Monique; Chiper, Manuela; Vandamme, Thierry; Markvicheva, Elena

    2016-06-15

    Development of novel anticancer formulations is a priority challenge in biomedicine. However, in vitro models based on monolayer cultures (2D) which are currently used for cytotoxicity tests leave much to be desired. More and more attention is focusing on 3D in vitro systems which can better mimic solid tumors. The aim of the study was to develop a novel one-step highly reproducible technique for multicellular tumor spheroid (MTS) formation using synthetic cyclic RGD-peptides, and to demonstrate availability of the spheroids as 3D in vitro model for antitumor drug testing. Cell self-assembly effect induced by addition of both linear and cyclic RGD-peptides directly to monolayer cultures was studied for 12 cell lines of various origins, including tumor cells (e.i. U-87 MG, MCF-7, M-3, HCT-116) and normal cells, in particular L-929, BNL.CL2, HepG2. Cyclo-RGDfK and its modification with triphenylphosphonium cation (TPP), namely cyclo-RGDfK(TPP) in a range of 10-100μM were found to induce spheroid formation. The obtained spheroids were unimodal with mean sizes in a range of 60-120μm depending on cell line and serum content in culture medium. The spheroids were used as 3D in vitro model, in order to evaluate cytotoxicity effects of antitumor drugs (doxorubicin, curcumin, temozolomide). The developed technique could be proposed as a promising tool for in vitro test of novel antitumor drugs. PMID:27107900

  18. Effects of atrial and brain natriuretic peptides upon cyclic GMP levels, potassium transport, and receptor binding in rat astrocytes

    The ability of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) to alter cyclic GMP levels and NaKCl cotransport in rat neocortical astrocytes was determined. At concentrations of 10(-9)-10(-6) M, rat ANP99-126 (rANF), rat ANP102-126 (auriculin B), and rat ANP103-126 (atriopeptin III) stimulated 6- to 100-fold increases in cyclic GMP levels. Porcine BNP (pBNP) and rat BNP (rBNP) were 20%-90% as effective as rANF over most of this concentration range, although 10(-6) M pBNP produced a greater effect than rANF. NaKCl cotransport as measured by bumetanide-sensitive 86Rb+ influx was not altered by exposure of astrocytes to 10(-6)M rANF, pBNP, or rBNP. Both pBNP and rBNP, as well as rat ANP103-123 (atriopeptin I) and des[gl18, ser19, gly20, leu21, gly22] ANF4-23-NH2 (C-ANF4-23) strongly competed for specific 125I-rANF binding sites in astrocyte membranes with affinities ranging from 0.03 to 0.4 nM, suggesting that virtually all binding sites measured at subnanomolar concentrations of 125I-rANF were of the ANP-C (ANF-R2) receptor subtype. These receptors are thought to serve a clearance function and may be linked to a guanylate cyclase activity that is chemically and pharmacologically distinct from that coupled to ANP-A (ANF-R1) receptors. ANP receptors on astrocytes may function in limiting the access of ANP and BNP to neurons involved in body fluid and cardiovascular regulation

  19. Synthesis of mixed MOR/KOR efficacy cyclic opioid peptide analogs with antinociceptive activity after systemic administration.

    Perlikowska, Renata; Piekielna, Justyna; Gentilucci, Luca; De Marco, Rossella; Cerlesi, Maria Camilla; Calo, Girolamo; Artali, Roberto; Tömböly, Csaba; Kluczyk, Alicja; Janecka, Anna

    2016-02-15

    Cyclic pentapeptide Tyr-c[D-Lys-Phe-Phe-Asp]NH2, based on the structure of endomorphin-2 (EM-2), which shows high affinity to the μ-opioid receptor (MOR) and a very strong antinociceptive activity in mice was used as a parent compound for the structure-activity relationship studies. In this report we synthesized analogs of a general sequence Dmt-c[D-Lys-Xaa-Yaa-Asp]NH2, with D-1- or D-2-naphthyl-3-alanine (D-1-Nal or D-2-Nal) in positions 3 or 4. In our earlier papers we have indicated that replacing a phenylalanine residue by the more extended aromatic system of naphthylalanines may result in increased bioactivities of linear analogs. The data obtained here showed that only cyclopeptides modified in position 4 retained the sub-nanomolar MOR and nanomolar κ-opioid receptor (KOR) affinity, similar but not better than that of a parent cyclopeptide. In the in vivo mouse hot-plate test, the most potent analog, Dmt-c[D-Lys-Phe-D-1-Nal-Asp]NH2, exhibited higher than EM-2 but slightly lower than the cyclic parent peptide antinociceptive activity after peripheral (ip) and also central administration (icv). Conformational analyses in a biomimetic environment and molecular docking studies disclosed the structural determinants responsible for the different pharmacological profiles of position 3- versus position 4-modified analogs. PMID:26785295

  20. Mannose-binding lectin gene polymorphisms are associated with disease activity and physical disability in untreated, anti-cyclic citrullinated peptide-positive patients with early rheumatoid arthritis

    Jacobsen, Søren; Garred, Peter; Madsen, Hans Ole;

    2009-01-01

    modifying antirheumatic drugs, participating in a treatment trial (CIMESTRA study) were examined at inclusion for MBL2 pooled structural genotypes (O/O, A/O, A/A), regulatory MBL2 promoter polymorphism in position -221 (XX, XY, YY), anti-cyclic citrullinated peptide 2 antibodies (anti-CCP2), disease...

  1. Anti-cyclic citrullinated peptide antibodies do not reflect self-reported disability and physical health in patients with rheumatoid arthritis of less than 5 years of duration

    Poulsen, Chalotte Heinsvig; Jacobsen, Søren; Frisch, Morten;

    2013-01-01

    It is well accepted that patients with antibodies against cyclic citrullinated peptides (anti-CCP) and rheumatoid arthritis (RA) suffer from more severe forms of RA in terms of clinical presentation and radiographic destruction at long term compared to anti-CCP-negative patients. The purpose of t...

  2. Influence of macrocyclic chelators on the targeting properties of (68Ga-labeled synthetic affibody molecules: comparison with (111In-labeled counterparts.

    Joanna Strand

    Full Text Available Affibody molecules are a class of small (7 kDa non-immunoglobulin scaffold-based affinity proteins, which have demonstrated substantial potential as probes for radionuclide molecular imaging. The use of positron emission tomography (PET would further increase the resolution and quantification accuracy of Affibody-based imaging. The rapid in vivo kinetics of Affibody molecules permit the use of the generator-produced radionuclide (68Ga (T1/2=67.6 min. Earlier studies have demonstrated that the chemical nature of chelators has a substantial influence on the biodistribution properties of Affibody molecules. To determine an optimal labeling approach, the macrocyclic chelators 1,4,7,10-tetraazacylododecane-1,4,7,10-tetraacetic acid (DOTA, 1,4,7-triazacyclononane-N,N,N-triacetic acid (NOTA and 1-(1,3-carboxypropyl-1,4,7- triazacyclononane-4,7-diacetic acid (NODAGA were conjugated to the N-terminus of the synthetic Affibody molecule ZHER2:S1 targeting HER2. Affibody molecules were labeled with (68Ga, and their binding specificity and cellular processing were evaluated. The biodistribution of (68Ga-DOTA-ZHER2:S1, (68Ga-NOTA-ZHER2:S1 and (68Ga-NODAGA-ZHER2:S1, as well as that of their (111In-labeled counterparts, was evaluated in BALB/C nu/nu mice bearing HER2-expressing SKOV3 xenografts. The tumor uptake for (68Ga-DOTA-ZHER2:S1 (17.9 ± 0.7%IA/g was significantly higher than for both (68Ga-NODAGA-ZHER2:S1 (16.13 ± 0.67%IA/g and (68Ga-NOTA-ZHER2:S1 (13 ± 3%IA/g at 2 h after injection. (68Ga-NODAGA-ZHER2:S1 had the highest tumor-to-blood ratio (60 ± 10 in comparison with both (68Ga-DOTA-ZHER2:S1 (28 ± 4 and (68Ga-NOTA-ZHER2:S1 (42 ± 11. The tumor-to-liver ratio was also higher for (68Ga-NODAGA-ZHER2:S1 (7 ± 2 than the DOTA and NOTA conjugates (5.5 ± 0.6 vs.3.3 ± 0.6. The influence of chelator on the biodistribution and targeting properties was less pronounced for (68Ga than for (111In. The results of this study demonstrate that macrocyclic

  3. Unguisin F, a new cyclic peptide from the endophytic fungus Mucor irregularis.

    Akone, Sergi H; Daletos, Georgios; Lin, Wenhan; Proksch, Peter

    2016-01-01

    The new cyclic heptapeptide unguisin F (1) and the known congener unguisin E (2), were obtained from the endophytic fungus Mucor irregularis, isolated from the medicinal plant Moringa stenopetala, collected in Cameroon. The structure of the new compound was unambiguously determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configuration of the amino acid residues of 1 and 2 was determined using Marfey's analysis. Compounds 1 and 2 were evaluated for their antibacterial and antifungal potential, but failed to display significant activities. PMID:26812868

  4. Investigating Surface Topology and Cyclic-RGD Peptide functionalization on Vascular Endothelialization

    McNichols, Colton; Wilkins, Justin; Kubota, Atsu; Shiu, Yan T.; Aouadi, Samir M.; Kohli, Punit

    2013-01-01

    The advantages of endothelialization of a stent surface in comparison with the bare metal and drug eluting stents used today include reduced late-stent restenosis and in-stent thrombosis. In this paper, we study the effect of surface topology and functionalization of tantalum (Ta) with cyclic-(arginine-glycine-aspartic acid-D-phenylalanine-lysine (cRGDfK)) on the attachment, spreading, and growth of vascular endothelial cells. Self-assembled nano-dimpling on Ta surfaces was performed using a ...

  5. Profiling anti-cyclic citrullinated peptide antibodies in patients with juvenile idiopathic arthritis

    Tebo Anne E; Jaskowski Troy; Davis K.; Whiting April; Clifford Bronte; Zeft Andrew; McNally Bernadette; Hill Harry R; Bohnsack John; Prahalad Sampath

    2012-01-01

    Abstract Background Anti-citrullinated protein/peptide antibodies (ACPA), have high specificity for rheumatoid arthritis (RA). Some children with juvenile idiopathic arthritis (JIA), phenotypically resemble RA and test positive for rheumatoid factor (RF) a characteristic biomarker of RA. We investigated the prevalence of ACPA and its relationship to other serologic markers associated with RA in a well-characterized JIA cohort. Methods Cases were 334 children with JIA, 30 of whom had RF + poly...

  6. Molecular Grafting onto a Stable Framework Yields Novel Cyclic Peptides for the Treatment of Multiple Sclerosis

    Wang, Conan K.; Gruber, Christian W.; Cemazar, Maša; Siatskas, Christopher; Tagore, Prascilla; Payne, Natalie; Sun, Guizhi; Wang, Shunhe; Bernard, Claude C.; Craik, David J.

    2013-01-01

    Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) and is characterized by the destruction of myelin and axons leading to progressive disability. Peptide epitopes from CNS proteins, such as myelin oligodendrocyte glycoprotein (MOG), possess promising immunoregulatory potential for treating MS; however, their instability and poor bioavailability is a major impediment for their use clinically. To overcome this problem, we used molecular grafting to incorporat...

  7. Separation and structure-mobility relationship study of cyclic antimicrobial peptides by capillary zone electrophoresis

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    Helsinki: -, 2015. YS5. [International Symposium on Electro- and Liquid Phase-Separation Techniques (ITP2015) /22./ and Nordic Separation Science Symposium (NoSSS2015) /8./. 30.08.2015-03.09.2015, Helsinki] R&D Projects: GA ČR(CZ) GA15-01948S Institutional support: RVO:61388963 Keywords : structure-mobility relationship * antimicrobial peptides * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  8. Factors that restrict intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E; Steffansen, Bente; Borchardt, Ronald T

    2009-01-01

    -Tyr-D-Ala-Gly-Phe-D-Leu-OH). AOA-DADLE, CA-DADLE, and OMCA-DADLE were shown to be rapidly metabolized by rat liver microsomes and human CYP-3A4 and to a lesser extent by esterases. Using an in situ perfused rat ileum model, ketoconazole, a CYP 3A inhibitor, was shown to have no effect (AOA-DADLE) or a slight enhancing effect...... (OMCA-DADLE, twofold; CA-DADLE, threefold) on their intestinal mucosal permeation. In contrast, inclusion of PSC-833, a P-gp inhibitor, in the perfusate significantly enhanced (7-16-fold) the permeation of the three cyclic prodrugs. Since PSC-833 was found to be a weak inhibitor of CYP 3A4 and to have...

  9. ISOLATION OF THE ANTIMICROBIAL CYCLIC PEPTIDE SUBTILOSIN A FROM A GUT-ASSOCIATED BACILLUS SUBTILIS STRAIN

    Ghislain Schyns

    2013-01-01

    Full Text Available The endospore-forming Bacillus subtilis has been used as probiotics over the last 50 years. However, little is known on how Bacillus spp act in the gut compared to other well-characterized probiotics such as lactic acid bacteria. It is believed that the competitive exclusion of pathogens results from different mode of action notably the production of antimicrobial compounds such as bacteriocins. Here, we report the characterization of the unexpected ability of a gut-associated B. subtilis BSP1 to synthetize the cyclic bacteriocin subtilosin A at high level. Our findings suggest that the BSP1 phenotype could be related, at least in part, to a subsequent increased expression level of the subtilosin A biosynthetic gene cluster sbo-alb in response to a higher activity of the stationery and sporulation master regulator Spo0A.

  10. What Goes around Comes around-A Comparative Study of the Influence of Chemical Modifications on the Antimicrobial Properties of Small Cyclic Peptides

    Margitta Dathe

    2013-09-01

    Full Text Available Tryptophan and arginine-rich cyclic hexapeptides of the type cyclo-RRRWFW combine high antibacterial activity with rapid cell killing kinetics, but show low toxicity in human cell lines. The peptides fulfil the structural requirements for membrane interaction such as high amphipathicity and cationic charge, but membrane permeabilisation, which is the most common mode of action of antimicrobial peptides (AMPs, could not be observed. Our current studies focus on elucidating a putative membrane translocation mechanism whereupon the peptides might interfere with intracellular processes. These investigations require particular analytical tools: fluorescent analogues and peptides bearing appropriate reactive groups were synthesized and characterized in order to be used in confocal laser scanning microscopy and HPLC analysis. We found that minimal changes in both the cationic and hydrophobic domain of the peptides in most cases led to significant reduction of antimicrobial activity and/or changes in the mode of action. However, we were able to identify two modified peptides which exhibited properties similar to those of the cyclic parent hexapeptide and are suitable for subsequent studies on membrane translocation and uptake into bacterial cells.

  11. The Cyclic Antibacterial Peptide Enterocin AS-48: Isolation, Mode of Action, and Possible Food Applications

    María José Grande Burgos

    2014-12-01

    Full Text Available Enterocin AS-48 is a circular bacteriocin produced by Enterococcus. It contains a 70 amino acid-residue chain circularized by a head-to-tail peptide bond. The conformation of enterocin AS-48 is arranged into five alpha-helices with a compact globular structure. Enterocin AS-48 has a wide inhibitory spectrum on Gram-positive bacteria. Sensitivity of Gram-negative bacteria increases in combination with outer-membrane permeabilizing treatments. Eukaryotic cells are bacteriocin-resistant. This cationic peptide inserts into bacterial membranes and causes membrane permeabilization, leading ultimately to cell death. Microarray analysis revealed sets of up-regulated and down-regulated genes in Bacillus cereus cells treated with sublethal bacteriocin concentration. Enterocin AS-48 can be purified in two steps or prepared as lyophilized powder from cultures in whey-based substrates. The potential applications of enterocin AS-48 as a food biopreservative have been corroborated against foodborne pathogens and/or toxigenic bacteria (Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enterica and spoilage bacteria (Alicyclobacillus acidoterrestris, Bacillus spp., Paenibacillus spp., Geobacillus stearothermophilus, Brochothrix thermosphacta, Staphylococcus carnosus, Lactobacillus sakei and other spoilage lactic acid bacteria. The efficacy of enterocin AS-48 in food systems increases greatly in combination with chemical preservatives, essential oils, phenolic compounds, and physico-chemical treatments such as sublethal heat, high-intensity pulsed-electric fields or high hydrostatic pressure.

  12. Association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope and smoking status in Brazilian patients with rheumatoid arthritis

    Yazbek, Michel Alexandre; de Barros-Mazon, Silvia; Rossi, Cláudio Lúcio; Londe, Ana Carolina; Costallat, Lilian Tereza Lavras; Bértolo, Manoel Barros

    2011-01-01

    INTRODUCTION: Epstein-Barr virus exposure appears to be an environmental trigger for rheumatoid arthritis that interacts with other risk factors. Relationships among anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status have been observed in patients with rheumatoid arthritis from different populations. OBJECTIVE: To perform an association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status in Brazilian patients with rheumatoid arthritis. METHODS: In a case-control study, 140 rheumatoid arthritis patients and 143 healthy volunteers who were matched for age, sex, and ethnicity were recruited. Anti-Epstein-Barr nuclear antigen-1 antibodies and anti-cyclic citrullinated peptide antibodies were examined using an enzyme-linked immunosorbent assay, and shared epitope alleles were identified by genotyping. Smoking information was collected from all subjects. A comparative analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status was performed in the patient group. Logistic regression analysis models were used to analyze the risk of rheumatoid arthritis. RESULTS: Anti-Epstein-Barr nuclear antigen-1 antibodies were not associated with anti-cyclic citrullinated peptide antibodies, shared epitope alleles, or smoking status. Anti-cyclic citrullinated peptide antibody positivity was significantly higher in smoking patients with shared epitope alleles (OR = 3.82). In a multivariate logistic regression analysis using stepwise selection, only anti-cyclic citrullinated peptide antibodies were found to be independently associated with rheumatoid arthritis (OR = 247.9). CONCLUSION: Anti-Epstein-Barr nuclear antigen-1 antibodies did not increase the risk of rheumatoid arthritis and were not associated with the rheumatoid arthritis risk factors studied. Smoking and

  13. Osteoblastic potency of bone marrow cells cultivated on functionalized biometals with cyclic RGD-peptide.

    Jäger, M; Böge, C; Janissen, R; Rohrbeck, D; Hülsen, T; Lensing-Höhn, S; Krauspe, R; Herten, M

    2013-10-01

    The fixation of cementless endoprostheses requires excellent fixation at the bone implant interface. Although the surface structures of these implants are designed to promote osteoblastic differentiation, poor bone quality may prevent or delay osseointegration. There is evidence that RGD peptides known as recognition motifs for various integrins, promote cellular adhesion, influence cellular proliferation, and differentiation of local cells. In this study, five different metal surfaces were analyzed: Sandblasted (TiSa) and polished (TiPol) Ti6Al4V, porocoated (CCPor) and polished (CCPol) cobalt chrome and polished stainless steel (SS) were coated by ethanol amine and poly(ethylene glycol) to attach covalently RGD peptides. Human mesenchymal stromal cells of healthy donors were cultivated onto prior functionalized metal surfaces for 14 days without osteogenic stimulation. Cell proliferation and differentiation were quantitatively evaluated for native (I), NaOH pre-activated (II), NaOH pre-activated, and PEG-coated (III) as well as for RGD (IV) coated surfaces. The RGD immobilization efficiency was analyzed by epi-fluorescence spectroscopy, cell morphology was documented by light and scanning electron microscopy. The RGD-binding efficiency was TiSa > TiPol > SS > CCPor > CCPol. RGD coated surfaces showed the highest average cell proliferation on CCPol > SS > CCPor > TiSa ≥ TiPol, whereas cellular differentiation mostly correlated with the observed proliferation results, such as CCPol > TiSa > SS > CCPor > TiPol. Considering statistical analyses (significance level of α = 0.05), the RGD-coating of all biometals in comparison and in respect of their particular controls showed no significant improvement in cellular proliferation and osteoblastic differentiation. PMID:23529934

  14. Inhibition of atrial natriuretic peptide-induced cyclic GMP accumulation in the bovine endothelial cells with anti-atrial natriuretic peptide receptor antiserum

    Using an antiserum raised against the purified atrial natriuretic peptide (ANP) receptor that has a disulfide-linked homodimeric structure and represents one subtype of the multiple ANP receptors, we showed that the receptor is coupled to the guanylate cyclase activation; formerly, this type of ANP receptor is not considered to be coupled to the cyclase. The specificity of the antiserum was determined by immunoblot analysis and immunoprecipitation. The anti-receptor antiserum did not compete with 125I-ANP for binding to the receptor but it lowered the affinity of the receptor. When added to bovine endothelial cell cultures, the antiserum blocked the cyclic GMP response of the cells triggered by ANP. These results indicate that the subtype of the ANP receptor recognized by the antiserum is responsible for the activation of particulate guanylate cyclase as well as the double function type receptor that has been assumed to contain both the receptor domain and the catalytic domain for cGMP synthesis on the same molecule. The presence of dissociative complexes of ANP receptor and particulate guanylate cyclase was also demonstrated by radiation inactivation analysis

  15. Dynamic PET and Optical Imaging and Compartment Modeling using a Dual-labeled Cyclic RGD Peptide Probe

    Lei Zhu, Ning Guo, Quanzheng Li, Ying Ma, Orit Jacboson, Seulki Lee, Hak Soo Choi, James R. Mansfield, Gang Niu, Xiaoyuan Chen

    2012-01-01

    Full Text Available Purpose: The aim of this study is to determine if dynamic optical imaging could provide comparable kinetic parameters to that of dynamic PET imaging by a near-infrared dye/64Cu dual-labeled cyclic RGD peptide.Methods: The integrin αvβ3 binding RGD peptide was conjugated with a macrocyclic chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA for copper labeling and PET imaging and a near-infrared dye ZW-1 for optical imaging. The in vitro biological activity of RGD-C(DOTA-ZW-1 was characterized by cell staining and receptor binding assay. Sixty-min dynamic PET and optical imaging were acquired on a MDA-MB-435 tumor model. Singular value decomposition (SVD method was applied to compute the dynamic optical signal from the two-dimensional optical projection images. Compartment models were used to quantitatively analyze and compare the dynamic optical and PET data.Results: The dual-labeled probe 64Cu-RGD-C(DOTA-ZW-1 showed integrin specific binding in vitro and in vivo. The binding potential (Bp derived from dynamic optical imaging (1.762 ± 0.020 is comparable to that from dynamic PET (1.752 ± 0.026.Conclusion: The signal un-mixing process using SVD improved the accuracy of kinetic modeling of 2D dynamic optical data. Our results demonstrate that 2D dynamic optical imaging with SVD analysis could achieve comparable quantitative results as dynamic PET imaging in preclinical xenograft models.

  16. Marine sponge cyclic peptide theonellamide A disrupts lipid bilayer integrity without forming distinct membrane pores.

    Espiritu, Rafael Atillo; Cornelio, Kimberly; Kinoshita, Masanao; Matsumori, Nobuaki; Murata, Michio; Nishimura, Shinichi; Kakeya, Hideaki; Yoshida, Minoru; Matsunaga, Shigeki

    2016-06-01

    Theonellamides (TNMs) are antifungal and cytotoxic bicyclic dodecapeptides derived from the marine sponge Theonella sp. These peptides specifically bind to 3β-hydroxysterols, resulting in 1,3-β-d-glucan overproduction and membrane damage in yeasts. The inclusion of cholesterol or ergosterol in phosphatidylcholine membranes significantly enhanced the membrane affinity of theonellamide A (TNM-A) because of its direct interaction with 3β-hydroxyl groups of sterols. To better understand TNM-induced membrane alterations, we investigated the effects of TNM-A on liposome morphology. (31)P nuclear magnetic resonance (NMR) and dynamic light scattering (DLS) measurements revealed that the premixing of TNM-A with lipids induced smaller vesicle formation. When giant unilamellar vesicles were incubated with exogenously added TNM-A, confocal micrographs showed dynamic changes in membrane morphology, which were more frequently observed in cholesterol-containing than sterol-free liposomes. In conjunction with our previous data, these results suggest that the membrane action of TNM-A proceeds in two steps: 1) TNM-A binds to the membrane surface through direct interaction with sterols and 2) accumulated TNM-A modifies the local membrane curvature in a concentration-dependent manner, resulting in dramatic membrane morphological changes and membrane disruption. PMID:27003125

  17. Processing Cyclic Peptide-polymer Conjugates in Block Copolymer Thin Films for Sub-nm Porous Membranes

    Zhang, Chen; Xu, Ting

    2014-03-01

    Porous thin films containing subnanometer channels oriented normal to the surface exhibit unique transport and separation properties and can serve as selective membranes for separation. Inspired by natural protein channels, we have developed an approach using cyclic peptide nanotubes (CPNs) embedded in polymeric matrix to mimic the transport of natural channels. The co-assembly of polymer-covered CPNs in a block copolymer (BCP) thin film requires the synchronization of two self-assembly processes, namely the microphase separation of BCP and the nanotube growth of CP-polymer conjugates. We systematically investigated the co-assembly of isolated CP-poly(ethylene glycol) (CP-PEG) conjugates and polystyrene-b-poly (methyl methacrylate) (PS-b-PMMA) in thin films as a function of CP-PEG loading (fCP-PEG) and solvent-polymer interactions. We find that there is a strong dependence of the co-assembly process on fCP-PEG due to thermodynamic limit of incorporating one CPN in one PMMA microdomain, as well as the kinetic pathway in which favorable PEG-solvent interaction helps to disperse CPNs and thus lowers the activation energy barrier of the system. This study presents critical insights in guided assemblies of functional building blocks within nanoscopic frameworks. DOE-EFRC-Gas Separation, Army Research Office.

  18. Association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope and smoking status in Brazilian patients with rheumatoid arthritis

    Michel Alexandre Yazbek

    2011-01-01

    Full Text Available INTRODUCTION: Epstein-Barr virus exposure appears to be an environmental trigger for rheumatoid arthritis that interacts with other risk factors. Relationships among anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status have been observed in patients with rheumatoid arthritis from different populations. OBJECTIVE: To perform an association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status in Brazilian patients with rheumatoid arthritis. METHODS: In a case-control study, 140 rheumatoid arthritis patients and 143 healthy volunteers who were matched for age, sex, and ethnicity were recruited. Anti-Epstein-Barr nuclear antigen-1 antibodies and anti-cyclic citrullinated peptide antibodies were examined using an enzyme-linked immunosorbent assay, and shared epitope alleles were identified by genotyping. Smoking information was collected from all subjects. A comparative analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status was performed in the patient group. Logistic regression analysis models were used to analyze the risk of rheumatoid arthritis. RESULTS: Anti-Epstein-Barr nuclear antigen-1 antibodies were not associated with anti-cyclic citrullinated peptide antibodies, shared epitope alleles, or smoking status. Anti-cyclic citrullinated peptide antibody positivity was significantly higher in smoking patients with shared epitope alleles (OR = 3.82. In a multivariate logistic regression analysis using stepwise selection, only anti-cyclic citrullinated peptide antibodies were found to be independently associated with rheumatoid arthritis (OR = 247.9. CONCLUSION: Anti-Epstein-Barr nuclear antigen-1 antibodies did not increase the risk of rheumatoid arthritis and were not associated with the rheumatoid arthritis risk factors studied. Smoking

  19. Effect of the excipient concentration on the pharmacokinetics of PM181104, a novel antimicrobial thiazolyl cyclic peptide antibiotic, following intravenous administration to mice

    Vijayaphanikumar Yemparala; Damre, Anagha A; Venkat Manohar; Kishori Sharan Singh; Mahajan, Girish B.; Satish N. Sawant; Tanaji Deokule; Sivaramakrishnan, H.

    2014-01-01

    Thiazolyl cyclic peptide antibiotics are known for their poor aqueous solubility and unfavorable pharmacokinetics (PK) and hence pose challenging tasks in developing these antibiotics as clinical candidates. In the current paper, we report a possible way to address these challenges with exemplification of our antibiotic PM181104. The approach was to prepare formulations with known excipients, Polysorbate 80 (Tween 80, T-80) and PEG 400 through their varied stiochiometric combination in approp...

  20. Solid-Phase Peptide Head-to-Side Chain Cyclodimerization: Discovery of C2-Symmetric Cyclic Lactam Hybrid α-Melanocyte-Stimulating Hormone (MSH)/Agouti-Signaling Protein (ASIP) Analogues with Potent Activities at the Human Melanocortin Receptors

    Mayorov, Alexander V.; Cai, Minying; Palmer, Erin S.; Liu, Zhihua; Cain, James P.; Vagner, Josef; Trivedi, Dev; Victor J. Hruby

    2010-01-01

    A novel hybrid melanocortin pharmacophore was designed based on the pharmacophores of the Agouti signaling protein (ASIP), an endogenous melanocortin antagonist, and α-melanocyte-stimulating hormone (α-MSH), an endogenous melanocortin agonist. The designed hybrid ASIP/MSH pharmacophore was explored in monomeric cyclic, and cyclodimeric templates. The monomeric cyclic disulfide series yielded peptides with hMC3R-selective non-competitive binding affinities. The direct on-resin peptide lactam c...

  1. Effects of tumour mass and circulating antigen on the biodistribution of 111In-labelled F(ab')2 fragments of human prostatic acid phosphatase monoclonal antibody in nude mice bearing PC-82 human prostatic tumor xenografts

    We have evaluated the effects of tumour mass and circulating antigen (prostatic acid phosphatase, PAP) on the biodistribution and the incorporation of 111In-labelled F(ab')2 monoclonal antibody (MoAb) fragments directed against human PAP into human prostatic tumours (PC-82; 0.1-8.9 g) growing in nude mice. The radioactivities in the blood, liver, spleen, kidney and tumour were compared at 1, 3, 4 and 6 days after the intravenous administration of the antibody fragments. There was a significant correlation between the tumour size and the serum PAP concentration in the model employed. Even tissue of a small tumour (111In-labelled F(ab')2 fragments. This relationship had levelled off by 72 h and most likely reflected a better vascularisation of the smaller tumours. Our results show that the increase in tumour size and in the concentration of circulating antigen in the blood led to decreased tumour-to-blood ratios, since there was a tendency for higher blood activities in mice with larger tumours and higher serum PAP concentrations. There was no correlation between tumour size and label uptake by the liver during the follow-up over 144 h, although serum PAP concentrations ranged from 3.1 μg/l to 352 μg/l. On the other hand, when compared with our previous data obtained with non-tumour-bearing mice, there was a significant increase in the uptake by the liver and spleen. These results indicate that even a small concentration of circulating antigen was able to trigger an abnormal change in the biodistribution of MoAbs. (orig.)

  2. Onset of polyarticular juvenile idiopathic arthritis with both anti-cyclic citrullinated peptide antibodies and rheumatoid factor in a 3-year-old girl

    Yasui Kozo

    2012-12-01

    Full Text Available Abstract This report describes 3 year old girl with the unusual presentation of polyarticular juvenile idiopathic arthritis (JIA with anti-cyclic citrullinated peptide (anti-CCP antibodies and a positive rheumatoid factor (RF. She was initially treated with a nonsteroidal anti-inflammatory drug (NSAID; ibuprofen followed by methotrexate (MTX, 10 mg/m2/week and prednisolone (0.25 mg/kg/day, but these treatments were ineffective. Administration of tocilizumab, a humanized antihuman interleukin-6 receptor monoclonal antibody, promptly improved her clinical manifestations, and she has been in complete remission (DAS28

  3. Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[D-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation.

    Li, Yangmei; Cazares, Margret; Wu, Jinhua; Houghten, Richard A; Toll, Laurence; Dooley, Colette

    2016-02-11

    To optimize the structure of a μ-opioid receptor ligand, analogs H-Tyr-c[D-Lys-Xxx-Tyr-Gly] were synthesized and their biological activity was tested. The analog containing a Phe(3) was identified as not only exhibiting binding affinity 14-fold higher than the original hit but also producing agonist activity 3-fold more potent than morphine. NMR study suggested that a trans conformation at D-Lys(2)-Xxx(3) is crucial for these cyclic peptides to maintain high affinity, selectivity, and functional activity toward the μ-opioid receptor. PMID:26789491

  4. Discovery and characterization of a novel cyclic peptide that effectively inhibits ephrin binding to the EphA4 receptor and displays anti-angiogenesis activity.

    Xiaofeng Han

    Full Text Available The EphA4 receptor tyrosine kinase regulates a variety of physiological and pathological processes during neural development and the formation of tumor blood vessels; thus, it represents a new and promising therapeutic target. We used a combination of phage peptide display and computer modeling/docking approaches and discovered a novel cyclic nonapeptide, now designated TYY. This peptide selectively inhibits the binding of the ephrinA5 ligand with EphA4 and significantly blocks angiogenesis in a 3D matrigel culture system. Molecular docking reveals that TYY recognizes the same binding pocket on EphA4 that the natural ephrin ligand binds to and that the Tyr3 and Tyr4 side chains of TYY are both critical for the TYY/EphA4 interaction. The discovery of TYY introduces a valuable probe of EphA4 function and a new lead for EphA4-targeted therapeutic development.

  5. 68Ga-Labeled Cyclic NGR Peptide for MicroPET Imaging of CD13 Receptor Expression

    Yahui Shao; Wansheng Liang; Fei Kang; Weidong Yang; Xiaowei Ma; Guiyu Li; Shu Zong; Kai Chen; Jing Wang

    2014-01-01

    Peptides containing the asparagines-glycine-arginine (NGR) motif have been identified as specific ligands binding to CD13/aminopeptidase N (APN) receptor, a tumor neovascular biomarker. In this study, we synthesized a novel NGR-containing peptide (NOTA-G3-NGR), and labeled NOTA-G3-NGR with 68Ga (t1/2 = 67.7 min). The resulting 68Ga-NOTA-G3-NGR peptide was subject to in vitro and in vivo characterization. The microPET imaging results revealed that the 68Ga-NOTA-G3-NGR peptide exhibits rapid an...

  6. Brain-natriuretic peptide and cyclic guanosine monophosphate as biomarkers of myxomatous mitral valve disease in dogs

    Moesgaard, Sophia Gry; Falk, Bo Torkel; Teerlink, Tom; Guðmundsdóttir, Halldóra Hrund; Sigurðardóttir, Sif; Rasmussen, Caroline Elisabeth; Olsen, Lisbeth Høier

    2011-01-01

    Elevations in the plasma concentrations of natriuretic peptides correlate with increased severity of myxomatous mitral valve disease (MMVD) in dogs. This study correlates the severity of MMVD with the plasma concentrations of the biomarkers N-terminal fragment of the pro-brain-natriuretic peptide...

  7. 68Ga-Labeled Cyclic NGR Peptide for MicroPET Imaging of CD13 Receptor Expression

    Yahui Shao

    2014-08-01

    Full Text Available Peptides containing the asparagines-glycine-arginine (NGR motif have been identified as specific ligands binding to CD13/aminopeptidase N (APN receptor, a tumor neovascular biomarker. In this study, we synthesized a novel NGR-containing peptide (NOTA-G3-NGR, and labeled NOTA-G3-NGR with 68Ga (t1/2 = 67.7 min. The resulting 68Ga-NOTA-G3-NGR peptide was subject to in vitro and in vivo characterization. The microPET imaging results revealed that the 68Ga-NOTA-G3-NGR peptide exhibits rapid and specific tumor uptake, and high tumor-to-background contrast in a subcutaneous HT-1080 fibrosarcoma mouse model. We concluded that the 68Ga-NOTA-G3-NGR peptide has potential in the diagnosis of CD13-targeted tumor angiogenesis.

  8. Imaging platelet deposition on Dacron bifurcation grafts in man: Quantification by a dual-tracer method using 111In-labeled platelets and sup(99m)Tc-labeled human serum albumin

    A dual tracer technique using 111In-labeled platelets and sup(99m)Tc-labeled human serum albumin was applied to evaluate the thrombogenicity of Dacron, bifurcation arterial grafts. The level of platelet accumulation over the whole of the graft was estimated from the ratio of 111In-platelet radioactivity deposited on the vascular wall to these radioactivity circulating in the blood pool, i.e., the platelet-accumulation index (PAI). Furthermore, the PAI value was calculated for each pixel in digitized images and the PAI distribution image (PAI image) was reconstructed. Eighteen patients with DeBakey knitted Dacron bifurcation grafts and 11 normal volunteers were studied. Of the 18 patients, 11 had no graft occlusion (group I) and the remaining 7 (group II) had occlusion. The mean PAI value (+-SD) over the whole of the graft in group I was 32.6%+-33.7% as compared to -8.8%+-4.5% in the control group (P2=10.55; P<0.005). The method used for platelet imaging in the present study may be useful in the study of platelet reactions on Dacron arterial prostheses. (orig.)

  9. Structural Modifications of ICAM-1 Cyclic Peptides to Improve the Activity to Inhibit Heterotypic Adhesion of T cells

    Iskandarsyah; Tejo, Bimo A.; Tambunan, Usman S. F.; Verkhivker, Gennady; SIAHAAN, TERUNA J.

    2008-01-01

    LFA-1/ICAM-1 interaction plays an important role in the formation of the immunological synapse between T cells and antigen-presenting cells (APC). Blocking of LFA-1/ICAM-1 interactions has been shown to suppress the progression of autoimmune diseases. cIBR peptide (cyclo(1,12)PenPRGGSVLVTGC) inhibits ICAM-1/LFA-1 interaction by binding to the I-domain of LFA-1. To increase the bioactivity of cIBR peptide, we systemically modified the structure of the peptide by (a) replacing the Pen residue a...

  10. Ammonia inhibits the C-type natriuretic peptide-dependent cyclic GMP synthesis and calcium accumulation in a rat brain endothelial cell line.

    Konopacka, Agnieszka; Zielińska, Magdalena; Albrecht, Jan

    2008-05-01

    Recently we reported a decrease of C-type natriuretic peptide (CNP)-dependent, natriuretic peptide receptor 2 (NPR2)-mediated cyclic GMP (cGMP) synthesis in a non-neuronal compartment of cerebral cortical slices of hyperammonemic rats [Zielińska, M., Fresko, I., Konopacka, A., Felipo, V., Albrecht, J., 2007. Hyperammonemia inhibits the natriuretic peptide receptor 2 (NPR2)-mediated cyclic GMP synthesis in the astrocytic compartment of rat cerebral cortex slices. Neurotoxicology 28, 1260-1263]. Here we accounted for the possible involvement of cerebral capillary endothelial cells in this response by measuring the effect of ammonia on the CNP-mediated cGMP formation and intracellular calcium ([Ca2+]i) accumulation in a rat cerebral endothelial cell line (RBE-4). We first established that stimulation of cGMP synthesis in RBE-4 cells was coupled to protein kinase G (PKG)-mediated Ca2+ influx from the medium which was inhibited by an L-type channel blocker nimodipine. Ammonia treatment (1h, 5mM NH4Cl) evoked a substantial decrease of CNP-stimulated cGMP synthesis which was related to a decreased binding of CNP to NPR2 receptors, and depressed the CNP-dependent [Ca2+]i accumulation in these cells. Ammonia also abolished the CNP-dependent Ca2+ accumulation in the absence of Na+. In cells incubated with ammonia in the absence of Ca2+ a slight CNP-dependent increase of [Ca2+]i was observed, most likely representing Ca2+ release from intracellular stores. Depression of CNP-dependent cGMP-mediated [Ca2+]i accumulation may contribute to cerebral vascular endothelial dysfunction associated with hyperammonemia or hepatic encephalopathy. PMID:18222015

  11. Design, synthesis, and characterization of new cyclic d,l-α-alternate amino acid peptides by capillary electrophoresis coupled to electrospray ionization mass spectrometry.

    Cortez-Díaz, María Dámaris; d'Orlyé, Fanny; Gutierrez-Granados, Silvia; de Leon-Rodriguez, Luis Manuel; Varenne, Anne

    2016-06-01

    The self-assembly of peptide nanotubes (PNTs) depends on the structure and chemistry of cyclic peptide (CP) monomers, having an impact on their properties, making the choice of their monomers and their characterization a great challenge. We synthesized for the first time a new set of eight original CP sequences of 8, 10, and 12 d,l-α-alternate amino acids with a controlled internal diameter from 7 to 13 Å. They present various properties (e.g., diameter, global surface charge, hydrophobicity) that can open the way to new applications. Their structure and purity were determined thanks to a capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) methodology developed for the first time for this purpose. The CPs were successfully separated in a basic hydro-organic background electrolyte (BGE, pH 8.0, H2O/EtOH 50:50, v/v) and analyzed in MS positive mode. The effect of CP structure on electrophoretic mobility was studied, and the mass spectra were deeply analyzed. This methodology allowed verifying their purity and the absence of linear peptide precursors as well as their stability when stored over several months. Therefore, we have developed a new CE-ESI-MS methodology for the structure and purity control of interesting potential precursors for PNTs that could be employed as nanoplatforms in diagnostics or as pseudo sieving tools for separative purposes. PMID:26969790

  12. Systemic and tumor-targeted delivery of siRNA by cyclic NGR and isoDGR motif-containing peptides.

    Huang, Yuanyu; Cheng, Qiang; Jin, Xingyu; Ji, Jia-Li; Guo, Shutao; Zheng, Shuquan; Wang, Xiaoxia; Cao, Huiqing; Gao, Shan; Liang, Xing-Jie; Du, Quan; Liang, Zicai

    2016-02-23

    The drug development of siRNA has been seriously hindered by the lack of an effective, safe and clinically applicable delivery system. The cyclic NGR motif and its isomerization product isoDGR recruit CD13 and integrin as their specific receptors, both of which are overexpressed by tumor and neovascular cells. In this study, a bi-functional peptide, named NGR-10R, was designed and tested for siRNA delivery in vitro and in vivo. Through the formation of peptide/siRNA nanoparticles, RNase resistance was greatly enhanced for the siRNAs. Both FACS and confocal assays revealed that the peptide/siRNA complexes were effectively internalized by MDA-MB-231 cells. Gene silencing assays indicated that anti-Lamin A/C siRNA delivered by NGR-10R robustly repressed gene expression in MDA-MB-231 and HUVEC (a CD13(+)/αvβ3(+) cell). Importantly, the siRNAs were efficiently delivered into tumor tissues and localized around the nuclei, as revealed by in vivo imaging and cryosection examination. In summary, NGR-10R not only efficiently delivered siRNAs into MDA-MB-231 cells in vitro but also delivered siRNAs into tumor cells in vivo, taking advantage of its specific binding to CD13 (neovascular) or αvβ3 (MDA-MB-231). Therefore, the NGR-10R peptide provides a promising siRNA delivery reagent that could be used for drug development, particularly for anti-tumor therapeutics. PMID:26783563

  13. Biodistribution in normal mice of an 111In-labelled prostatic acid phosphatase-specific antibody and its F(ab')2 fragments derivatized site-specifically or via bicyclic diethylenetriaminepentaacetic acid anhydride

    We examined the optimization of derivatization of monoclonal antibodies and their fragments intended for use as radiopharmaceutical in radioimaging and/or radioimmunotherapy of prostatic cancer. Two different principles were used to conjugate (DTPA) to a monoclonal antibody (Mab, subclass IgG1) raised against human prostatic acid phosphatase (PAP). In addition, the F(ab')2 fragments of this Mab were also derivatized. The biodistribution of the 111In-labelled derivatives was investigated in normal mice. All the derivatives of IgG1 demonstrated a slower blood clearance than the corresponding derivatives of the F(ab')2 fragments. This property was particularly pronounced in the site-specifically conjugated derivatives of IgG1. All the derivatives studied accumulated in the liver, kidney, and spleen. The CA-DTPA derivatives of F(ab')2 fragments showed the highest kidney-to-blood ratios of radioactivity. The derivatives of IgG1 showed a higher percentage of the injected dose in liver and spleen tissues than the derivatives of the F(ab')2 fragments. The F(ab')2 fragments studied also gave rise to site-specific derivatives, which demonstrated that carbohydrates were also present in this part of the molecule. They behaved similarly to the CA-DTPA F(ab')2 derivative in other respects, but the kidney accumulation was lower at 72 and 120 h. The F(ab')2 fragments studied would be better suited for radioimaging than the derivatives of the IgG1 studied. In contrast, the derivatives of IgG1, especially the p-NH2-Bz-DTPA conjugate, might be more suitable candidates for the development of therapeutic agents. (orig.)

  14. 99mTc-EDDA/HYNIC-TOC: a new 99mTc-labelled radiopharmaceutical for imaging somatostatin receptor-positive tumours: first clinical results and intra-patient comparison with 111In-labelled octreotide derivatives

    [111In-diethylene triamine penta-acetic acid-d-Phe1]-octreotide (DTPA-octreotide) scintigraphy has gained widespread acceptance as a diagnostic clinical procedure in oncology for imaging somatostatin receptor-positive tumours. However, indium-111 as a radiolabel has several drawbacks, including limited availability, suboptimal gamma energy and high radiation burden to the patient. We have recently reported on the preclinical development of 99mTc-EDDA/HYNIC-TOC, a new octreotide derivative which showed promising results both in vitro and in vivo. We now report our initial clinical experiences with this new radiopharmaceutical in ten oncological patients. The clinical diagnoses were: carcinoid syndrome (n=5), thyroid cancer (n=3), pancreatic cancer (n=1) and pituitary tumour (n=1). The biodistribution and kinetics of 99mTc-EDDA/HYNIC-TOC were compared with those of 111In-DTPA-octreotide in six cases, and with those of 111In-DOTA-TOC in five cases. With the new tracer tumours were imaged within 15 min after injection and showed the highest target/non-target ratios 4 h after injection. Tumour uptake persisted up to 20 h p.i. The rate of blood clearance was similar to that of 111In-DTPA-octreotide but faster than that of 111In-DOTA-TOC, while urinary excretion was lower compared with the 111In derivatives. Semi-quantitative region of interest analysis showed that 99mTc-EDDA/HYNIC-TOC produced higher tumour/organ (target/non-target) ratios than the 111In derivatives, especially in relation to heart and muscle. Significantly more lesions could be detected in 99mTc images. We conclude that 99mTc-EDDA/HYNIC-TOC shows better imaging properties for the identification of somatostatin receptor-positive tumour sites than currently available 111In-labelled octreotide derivatives. (orig.)

  15. Low-field magnetic resonance imaging or combined ultrasonography and anti-cyclic citrullinated peptide antibody improve correct classification of individuals as established rheumatoid arthritis

    Pedersen, Jens K; Lorenzen, Tove; Ejbjerg, Bo;

    2014-01-01

    /specificity) was 78% (62%/94%) (classification) and 85% (69%/100%) (diagnosis), while for the total synovitis score of MCP joints plus wrist (cut-off ≥10) it was 78% (62%/94%) (both classification and diagnosis). CONCLUSIONS: Compared with the ACR 1987 criteria, low-field MRI alone or adapted criteria......BACKGROUND: The aim of the present study was to evaluate the accuracy of two approaches using magnetic resonance imaging (MRI) or combined ultrasonography (US) and anti-cyclic citrullinated peptide antibody (ACPA) for diagnosis and classification of individuals with established rheumatoid arthritis...... erosions on radiography with synovitis and erosions detected by US on a semi-quantitative scale), and RA MRI scoring System (RAMRIS) scores on low-field MRI in the unilateral hand. RESULTS: For the ACR 1987 criteria the ROC-area was 75% (sensitivity/specificity = 50%/100%) (with "classification" as...

  16. Hormonal Neuroendocrine and Vasoconstrictor Peptide Responses of Ball Game and Cyclic Sport Elite Athletes by Treadmill Test

    Anna Protzner; Márta Szmodis; Anna Udvardy; Edit Bosnyák; Emese Trájer; Zsolt Komka; István Györe; Miklós Tóth

    2015-01-01

    Objective Our objective was to evaluate complex hormonal response in ball game and cyclic sport elite athletes through an incremental treadmill test, since, so far, variables in experimental procedures have often hampered comparisons of data. Methods We determined anthropometric data, heart rate, maximal oxygen uptake, workload, plasma levels of lactate, adrenaline, noradrenaline, dopamine, cortisol, angiontensinogen and endothelin in control (n = 6), soccer (n = 8), handball (n = 12), kayaki...

  17. Hormonal Neuroendocrine and Vasoconstrictor Peptide Responses of Ball Game and Cyclic Sport Elite Athletes by Treadmill Test.

    Anna Protzner

    Full Text Available Our objective was to evaluate complex hormonal response in ball game and cyclic sport elite athletes through an incremental treadmill test, since, so far, variables in experimental procedures have often hampered comparisons of data.We determined anthropometric data, heart rate, maximal oxygen uptake, workload, plasma levels of lactate, adrenaline, noradrenaline, dopamine, cortisol, angiontensinogen and endothelin in control (n = 6, soccer (n = 8, handball (n = 12, kayaking (n = 9 and triathlon (n = 9 groups based on a Bruce protocol through a maximal exercise type of spiroergometric test.We obtained significant increases for adrenaline, 2.9- and 3.9-fold by comparing the normalized means for soccer players and kayakers and soccer players and triathletes after/before test, respectively. For noradrenaline, we observed an even stronger, three-time significant difference between each type of ball game and cyclic sport activity.Exercise related adrenaline and noradrenaline changes were more pronounced than dopamine plasma level changes and revealed an opportunity to differentiate cyclic and ball game activities and control group upon these parameters. Normalization of concentration ratios of the monitored compounds by the corresponding maximal oxygen uptake reflected better the differences in the response level of adrenaline, noradrenaline, dopamine and cortisol.

  18. Responses of plasma cyclic AMP, serum immunoreactive insulin, C-peptide immunoreactivity and blood sugar levels to glucagon in patients with liver diseases.

    Shimamura,Junnosuke

    1985-10-01

    Full Text Available Levels of plasma cyclic AMP, serum immunoreactive insulin (IRI, serum c-peptide immunoreactivity (CPR and blood sugar (BS were determined 0, 15, 30, 45 and 60 min after a glucagon injection (0.01 mg per kg body weight in normal controls, patients with acute hepatitis and liver cirrhosis. Plasma cyclic AMP responses to glucagon in liver disease patients varied widely in peak value, and only in patients with fulminant hepatitis and decompensated liver cirrhosis with poor prognosis was the response suppressed. The peak response of BS was found significantly later in liver cirrhosis patients than in normal controls. IRI and CPR responses to glucagon were lower in acute hepatitis patients than in normal controls and liver cirrhosis patients. IRI levels and their sum were also lower in acute hepatitis patients, although CPR levels were not significantly different. Thus, the ratio of the sum of CPR from 0 to 60 min to that of IRI was significantly higher in acute hepatitis, indicating impaired pancreatic secretion of insulin to glucagon stimulation as well as increased uptake of insulin by the liver in acute hepatitis.

  19. The Diagnostic Utility of Anti-cyclic Citrullinated Peptide Antibodies, Matrix Metalloproteinase-3, Rheumatoid Factor, Erythrocyte Sedimentation Rate, and C-reactive Protein in Patients with Erosive and Non-erosive Rheumatoid Arthritis

    O. Shovman

    2005-01-01

    Full Text Available Objective: To compare the diagnostic utility of laboratory variables, including matrix metalloproteinase-3 (MMP-3, anti-cyclic citrullinated peptide (CCP antibodies, rheumatoid factor (RF, erythrocyte sedimentation rate (ESR, and C-reactive protein (CRP in patients with erosive and non-erosive rheumatoid arthritis (RA.

  20. Grb7 SH2 domain structure and interactions with a cyclic peptide inhibitor of cancer cell migration and proliferation

    Pero Stephanie C

    2007-09-01

    Full Text Available Abstract Background Human growth factor receptor bound protein 7 (Grb7 is an adapter protein that mediates the coupling of tyrosine kinases with their downstream signaling pathways. Grb7 is frequently overexpressed in invasive and metastatic human cancers and is implicated in cancer progression via its interaction with the ErbB2 receptor and focal adhesion kinase (FAK that play critical roles in cell proliferation and migration. It is thus a prime target for the development of novel anti-cancer therapies. Recently, an inhibitory peptide (G7-18NATE has been developed which binds specifically to the Grb7 SH2 domain and is able to attenuate cancer cell proliferation and migration in various cancer cell lines. Results As a first step towards understanding how Grb7 may be inhibited by G7-18NATE, we solved the crystal structure of the Grb7 SH2 domain to 2.1 Å resolution. We describe the details of the peptide binding site underlying target specificity, as well as the dimer interface of Grb 7 SH2. Dimer formation of Grb7 was determined to be in the μM range using analytical ultracentrifugation for both full-length Grb7 and the SH2 domain alone, suggesting the SH2 domain forms the basis of a physiological dimer. ITC measurements of the interaction of the G7-18NATE peptide with the Grb7 SH2 domain revealed that it binds with a binding affinity of Kd = ~35.7 μM and NMR spectroscopy titration experiments revealed that peptide binding causes perturbations to both the ligand binding surface of the Grb7 SH2 domain as well as to the dimer interface, suggesting that dimerisation of Grb7 is impacted on by peptide binding. Conclusion Together the data allow us to propose a model of the Grb7 SH2 domain/G7-18NATE interaction and to rationalize the basis for the observed binding specificity and affinity. We propose that the current study will assist with the development of second generation Grb7 SH2 domain inhibitors, potentially leading to novel inhibitors of

  1. Determination of cyclic nucleotide-dependent protein kinase substrate specificity by the use of peptide libraries on cellulose paper.

    Tegge, W; Frank, R; Hofmann, F; Dostmann, W R

    1995-08-22

    An iterative approach to the a priori determination of the substrate specificity of cAMP- and cGMP-dependent protein kinases (PKA and PKG) by the use of peptide libraries on cellulose paper is described. The starting point of the investigation was an octamer library with the general structure Ac-XXX12XXX, where X represents mixtures of all 20 natural amino acids and 1 and 2 represent individual amino acid residues. The library thus contained all possible 2.56 x 10(10) octamers, divided into 400 sublibraries with defined amino acids 1 and 2 each consisting of 6.4 x 10(7) sequences. After phosphorylation with the kinases in the presence of [gamma-32P]ATP, the sublibrarys Ac-XXXRRXXX and Ac-XXXRKXXX were identified as the best substrates for PKA and PKG, respectively. The second-generation libraries had the structures Ac-XXXRR12X and Ac-XXXRK12X for PKA and PKG and resulted in the most active sequence pools Ac-XXXRRASX and Ac-XXXRKKSX. After delineation of every position in the octameric sequence and extension of the investigation to decameric peptides, the best sequences, Ac-KRAERKASIY and Ac-TQKARKKSNA, were obtained for PKA and PKG, respectively. Promising octameric and decameric peptides were assembled 5 or 10 times each and assayed in order to determine the experimental scatter inherent in the approach. The kinetic data of several octameric and decameric sequences were determined in solution and compared to data for known substrates. The recognition motif of PKA was confirmed by this approach, and a novel substrate sequence for PKG was identified.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7654713

  2. Preparation and evaluation of 99mTc-labeled cyclic arginine-glycine-aspartate (RGD) peptide for integrin targeting

    Technetium coordination chemistry has been a subject of interest in the development of radiopharmaceuticals, especially imaging radiotracers. Due to the extensive work done on developing chelates for 99mTc, various chelators have been investigated and applied to radiopharmceuticals. Previous studies on the coordination chemistry of the [99mTc=O] core have established peptide-derived sequences as effective chelating ligands. These observations led to the design of tetradentate ligands derived from amino acid sequences. Such amino acid sequences provide a tetradentate coordination site for chelation to the radionuclide and an effective functional group for conjugation to biomolecules using conventional solid-phase synthetic routes. A derivative of a novel tripeptide chelating sequence, Pro-Gly-Cys (PGC) has been developed where it is possible to form stable technetium complexes with the [99mTc=O] via N3S1 tetradentate coordination core that serves this function and can be readily incorporated into biomolecules using solid-phase synthesis techniques. As a model system, the RGD peptide was selected which has been well known to target the integrin receptor for angiogenesis and tumor imaging agents. The results of in vivo studies with these novel radiolabeled compounds in tumor xenografts demonstrated a distribution in tumor targeting and other organs, such as kidney, liver and intestines.

  3. Hyperammonemia inhibits the natriuretic peptide receptor 2 (NPR-2)-mediated cyclic GMP synthesis in the astrocytic compartment of rat cerebral cortex slices.

    Zielińska, Magdalena; Fresko, Inez; Konopacka, Agnieszka; Felipo, Vicente; Albrecht, Jan

    2007-11-01

    The decrease of cyclic GMP (cGMP) level in the brain, contributing to cognitive and memory deficit in hyperammonemia (HA), has been attributed to the interference of ammonia with the NMDA/nitric oxide/soluble guanylate cyclase (GC)/cGMP pathway in neurons. The present study tested the hypotheses that (a) HA also affects cGMP synthesis elicited by stimulation of the natriuretic peptide receptor 2 (NPR-2) with its natural ligand, C-type natriuretic peptide (CNP) and (b) the latter effect may involve astrocytes, the ammonia-sensitive cells. In the cerebral cortical slices of control rats, CNP stimulated cGMP synthesis in a degree comparable to the NO donor, S-nitroso-N-acetylpenicillamine (SNAP) used at an optimal concentration. Fluoroacetate (FA), a metabolic inhibitor specifically affecting astrocytic mitochondria, inhibited the CNP-dependent cGMP synthesis by about 50%. Ammonium acetate-induced HA decreased by 68% the CNP-dependent cGMP generation in slices incubated in the absence of FA. In slices incubated in the presence of FA, cGMP synthesis in slices derived from HA rats did not differ from that in control slices. The results indicate that HA inhibits CNP-dependent cGMP synthesis in the FA-vulnerable, astrocytic compartment, but not in the FA-resistant compartment(s) of the brain. HA did not affect the expression of NPR-2 mRNA in the cerebral cortex tissue as tested using real-time PCR, indicating that the effect of ammonia involves as yet unidentified events occurring posttranscriptionally. Deregulation of NPR-2 function in astrocytes by ammonia may contribute to neurophysiological symptoms of HA. PMID:17629948

  4. Isolation, structural characterization, and properties of mattacin (polymyxin M), a cyclic peptide antibiotic produced by Paenibacillus kobensis M.

    Martin, Nathaniel I; Hu, Haijing; Moake, Matthew M; Churey, John J; Whittal, Randy; Worobo, Randy W; Vederas, John C

    2003-04-11

    Mattacin is a nonribosomally synthesized, decapeptide antibiotic produced by Paenibacillus kobensis M. The producing strain was isolated from a soil/manure sample and identified using 16 S rRNA sequence homology along with chemical and morphological characterization. An efficient production and isolation procedure was developed to afford pure mattacin. Structure elucidation using a combination of chemical degradation, multidimensional NMR studies (COSY, HMBC, HMQC, ROESY), and mass spectrometric (MALDI MS/MS) analyses showed that mattacin is identical to polymyxin M, an uncommon antibiotic reported previously in certain Bacillus species by Russian investigators. Mattacin (polymyxin M) is cyclic and possesses an amide linkage between the C-terminal threonine and the side chain amino group of the diaminobutyric acid residue at position 4. It contains an (S)-6-methyloctanoic acid moiety attached as an amide at the N-terminal amino group, one D-leucine, six L-alpha,gamma-diaminobutyric acid, and three L-threonine residues. Transfer NOE experiments on the conformational preferences of mattacin when bound to lipid A and microcalorimetry studies on binding to lipopolysaccharide showed that its behavior was very similar to that observed in previous studies of polymyxin B (a commercial antibiotic), suggesting an identical mechanism of action. It was capable of inhibiting the growth of a wide variety of Gram-positive and Gram-negative bacteria, including several human and plant pathogens with activity comparable with purified polymyxin B. The biosynthesis of mattacin was also examined briefly using transpositional mutagenesis by which 10 production mutants were obtained, revealing a set of genes involved in production. PMID:12569104

  5. Anti-Cyclic Citrullinated Peptide Antibodies and Severity of Interstitial Lung Disease in Women with Rheumatoid Arthritis

    Alberto Daniel Rocha-Muñoz

    2015-01-01

    Full Text Available Objective. To evaluate whether serum titers of second-generation anticyclic citrullinated peptide antibodies (anti-CCP2 are associated with the severity and extent of interstitial lung disease in rheumatoid arthritis (RA-ILD. Methods. In across-sectional study, 39 RA-ILD patients confirmed by high-resolution computed tomography (HRCT were compared with 42 RA without lung involvement (RA only. Characteristics related to RA-ILD were assessed in all of the patients and serum anti-CCP2 titers quantified. Results. Higher anti-CCP2 titers were found in RA-ILD compared with RA only (medians 77.9 versus 30.2 U/mL, P<0.001. In the logistic regression analysis after adjustment for age, disease duration (DD, smoke exposure, disease activity, functioning, erythrocyte sedimentation rate, and methotrexate (MTX treatment duration, the characteristics associated with RA-ILD were higher anti-CCP2 titers (P=0.003 and + RF (P=0.002. In multivariate linear regression, the variables associated with severity of ground-glass score were anti-CCP2 titers (P=0.02 and with fibrosis score DD (P=0.01, anti-CCP2 titers (P<0.001, and MTX treatment duration (P<0.001. Conclusions. Anti-CCP2 antibodies are markers of severity and extent of RA-ILD in HRCT. Further longitudinal studies are required to identify if higher anti-CCP2 titers are associated with worst prognosis in RA-ILD.

  6. Anti-Cyclic Citrullinated Peptide (Anti-CCP and Anti-Mutated Citrullinated Vimentin (Anti-MCV Relation with Extra-Articular Manifestations in Rheumatoid Arthritis

    Laura Gonzalez-Lopez

    2014-01-01

    Full Text Available We evaluated the association between anti-cyclic citrullinated peptide antibodies (anti-CCP and anti-mutated citrullinated vimentin antibodies (anti-MCV with the presence of extra-articular (ExRA manifestations in 225 patients with rheumatoid arthritis (RA. Ninety-five patients had ExRA and 130 had no ExRA. There was no association of anti-CCP and anti-MCV levels with the presence of ExRA as total group (P=0.40 and P=0.91, resp.. Making an analysis of individual manifestations, rheumatoid nodules were associated with positivity for rheumatoid factor (RF; (P=0.01, anti-CCP (P=0.048, and anti-MCV (P=0.02. Instead, RF, anti-CCP, or anti-MCV were not associated with SS, chronic anemia, or peripheral neuropathy. Levels of anti-CCP correlated with the score of the Health Assessment Questionnaire-Disability Index (HAQ-Di (r=0.154, P=0.03, erythrocyte sedimentation rate (ESR; (r=0.155, P=0.03, and RF (P=0.254, P<0.001, whereas anti-MCV titres only correlated with RF (r=0.169, P=0.02. On adjusted analysis, ExRA was associated with longer age (P=0.015, longer disease duration (P=0.007, higher DAS-28 score (P=0.002, and higher HAQ-DI score (P=0.007, but serum levels of anti-CCP and anti-MCV were not associated. These findings show the need to strengthen the evaluation of the pathogenic mechanisms implied in each specific ExRA manifestation.

  7. A novel Indium-111-labeled gonadotropin-releasing hormone peptide for human prostate cancer imaging

    Guo, Haixun; Gallazzi, Fabio; Sklar, Larry A.; Miao, Yubin

    2011-01-01

    The purpose of this study was to evaluate the tumor targeting and imaging properties of a novel 111In-labeled gonadotropin-releasing hormone (GnRH) peptide {1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-Ahx-(d-Lys6-GnRH1)} for human prostate cancer. The biodistribution and tumor imaging properties of 111In-DOTA-Ahx-(d-Lys6-GnRH1) were determined in DU145 human prostate cancer-xenografted nude mice. 111In-DOTA-Ahx-(d-Lys6-GnRH1) exhibited rapid tumor uptake (1.27 ± 0.40 %ID/g...

  8. Differential Mobility Spectrometry Coupled with Multiple Ion Monitoring in Regulated LC-MS/MS Bioanalysis of a Therapeutic Cyclic Peptide in Human Plasma.

    Fu, Yunlin; Xia, Yuan-Qing; Flarakos, Jimmy; Tse, Francis L S; Miller, Jeffrey D; Jones, Elliott B; Li, Wenkui

    2016-04-01

    A differential mobility spectrometry (DMS) in combination with a multiple ion monitoring (MIM) method was developed and validated for quantitative LC-MS/MS bioanalysis of pasireotide (SOM230) in human plasma. Pasireotide, a therapeutic cyclic peptide, exhibits poor collision-induced dissociation (CID) efficiency for multiple reaction monitoring (MRM) detection. Therefore, in an effort to increase the overall sensitivity of the assay, a DMS-MIM approach was explored. By selecting the most abundant doubly charged precursor ion in both the Q1 and Q3 of the mass analyzer in MIM and combining the DMS capability to significantly reduce the high matrix/chemical background noise, this new LC-DMS-MIM method overcomes the sensitivity challenge in the typical MRM method due to poor CID fragmentation of the analyte. Human plasma was spiked with pasireotide with concentrations in the range 0.01-50 ng/mL. Weak cation-exchange solid-phase extraction was employed for sample preparation. The sample extracts were analyzed with a SCIEX QTRAP 6500 system equipped with an ESI source and DMS device. The separation voltage and compensation voltage of the DMS and other parameters of the MS system were optimized to maximize signal responses. The performance of the LC-DMS-MIM assay for quantitative analysis of pasireotide in human plasma was evaluated and compared to those obtained via LC-MRM and LC-MIM without DMS. Overall, the assay sensitivity with DMS-MIM was approximately 5-fold better than that observed in MRM or MIM without DMS. The assay was validated with accuracy (% bias) and precision (% CV) of the QC results at eight concentration levels (0.01, 0.02, 0.05, 0.15, 0.3, 1.5, 15, and 37.5 ng/mL) evaluated ranging from -4.8 to 5.0% bias and 0.7 to 8.6% CV for the intraday and interday runs. The current LC-DMS-MIM workflow can be expanded to quantitative analysis of other molecules that have poor fragmentation efficiency in CID. PMID:26937555

  9. Smoking in combination with antibodies to cyclic citrullinated peptides is associated with persistently high levels of survivin in early rheumatoid arthritis: a prospective cohort study

    2014-01-01

    Introduction High levels of the oncoprotein survivin may be detected in the majority of patients with early rheumatoid arthritis (RA). Survivin is a sensitive predictor of joint damage and persistent disease activity. Survivin-positive patients are often poor responders to antirheumatic and biological treatment. The aim of this study was to investigate the reproducibility of survivin status and its significance for clinical and immunological assessment of RA patients. Methods Survivin levels were measured in 339 patients from the Better Anti-Rheumatic FarmacOTherapy (BARFOT) cohort of early RA at baseline and after 24 months. The association of survivin status with joint damage (total Sharp-van der Heijde score), disease activity (Disease Activity Score based on evaluation of 28 joints (DAS28)), functional disability (Health Assessment Questionnaire (HAQ)), and pain perception (Visual Analogue Scale (VAS)) was calculated in the groups positive and negative for survivin on both occasions, and for the positive-negative and negative-positive groups. Results In 268 patients (79%) the levels of survivin were similar at baseline and after 24 months, 15% converted from survivin-positive to survivin-negative, and 5% from survivin-negative to survivin-positive. A combination of smoking and antibodies against cyclic citrullinated peptides (aCCP) predicted persistently (baseline and 24 months) high levels of survivin (odds ratio 4.36 (95% CI: 2.64 to 7.20), P < 0.001), positive predictive value 0.66 and specificity 0.83). The independent nature of survivin and aCCP was demonstrated by statistical and laboratory analysis. Survivin positivity on both test occasions was associated with the progression of joint damage, significantly higher DAS28 and lower rate of remission at 24 and 60 months compared to negative-negative patients. Survivin status was less associated with changes in HAQ and VAS. Conclusions Survivin is a relevant and reproducible marker of severe RA

  10. PET imaging of αvβ3 integrin expression in tumours with 68Ga-labelled mono-, di- and tetrameric RGD peptides

    Dijkgraaf, Ingrid; Yim, Cheng-Bin; Franssen, Gerben M.; Schuit, Robert C; Luurtsema, Gert; Liu, Shuang; Oyen, Wim J. G.; Boerman, Otto C.

    2010-01-01

    Purpose Due to the restricted expression of αvβ3 in tumours, αvβ3 is considered a suitable receptor for tumour targeting. In this study the αvβ3-binding characteristics of 68Ga-labelled monomeric, dimeric and tetrameric RGD peptides were determined and compared with their 111In-labelled counterparts. Methods A monomeric (E-c(RGDfK)), a dimeric (E-[c(RGDfK)]2) and a tetrameric (E{E[c(RGDfK)]2}2) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with 68Ga. In vitro αvβ3-bindi...

  11. Use of Galerina marginata genes and proteins for peptide production

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2016-03-01

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  12. Macrophage-inducible C-type lectin is associated with anti-cyclic citrullinated peptide antibodies-positive rheumatoid arthritis in men

    WU Xin-yu; GUO Jian-ping; YIN Fang-rui; LU Xiao-lan; LI Ru; HE Jing; LIU Xu; LI Zhan-guo

    2012-01-01

    Background Macrophage-inducible C-type lectin (MINCLE) is an important member of C-type lectin superfamily,which has been shown evidence for susceptibility to arthritis in animal models.We aimed to investigate the possible association of MINCLE with rheumatoid arthritis (RA) susceptibility in Chinese Hart population.Methods Haplotypes from HapMap database (Chinese Hart Beijing,CHB) were used to select tag-single nucleotide polymorphism (SNP) (r2=0.8) residing in MINCLE gene.A total of 563 patients with RA and 404 healthy controls were TagMan genotyped for SNP rs10841845.Association analyses were performed on the whole data set and on RA subsets based on gender difference and the status of anti-cyclic citrullinated peptide (anti-CCP) antibody in RA patients.Association statistics were calculated by age and sex adjusted logistic regression.Results Overall,MINCLE SNP rs10841845 was not associated with susceptibility to RA.However,following anti-CCP stratification,rs10841845 GG genotypes conferred a significantly protective effects against anti-CCP-positive RA (OR 0.65,95% CI 0.430-0.995,P=0.048).Following gender stratification,SNP rs10841845 G allele appeared to insert its RA protective effect only in male patients,both at allele level (G vs.A OR 0.66,95% CI 0.46-0.93,P=0.018) and at genotype level (GG vs.AA+AG,OR 0.429,95% CI 0.20-0.95,P=0.036).Notably,the male RA protective effect of rs10841845 G allele was only seen in anti-CCP-positive RA (G vs.A:OR 0.64,95% CI 0.43-0.96,P=0.029; GG vs.AA+AG:OR 0.375,95% Cl 0.14-0.94,P=0.038).Furthermore,we observed a significant reduction of Disease Activity Score (DAS) 28 score (3.91±0.70 vs.5.66±0.31,P=0.022) and serum C-reactive protein levels (31.64±24.13 vs.91.80±12.02,P=0.012)in male anti-CCP-positive RA patients carrying rs10841845 GG genotype,compared with patients carrying AA+AG genotypes.Conclusions Our study provides the evidence for a gender specific association between MINCLE rs10841845 and RA

  13. Total synthesis of cyclomarins A, C and D, marine cyclic peptides with interesting anti-tuberculosis and anti-malaria activities.

    Barbie, Philipp; Kazmaier, Uli

    2016-07-01

    Cyclomarins are cyclic heptapeptides containing four unusual amino acids. New synthetic protocols toward their synthesis have been developed, leading to the synthesis and biological evaluation of three natural occurring cyclomarins. Interestingly, cyclomarins address two completely different targets: Clp C1, a subunit of the caseinolytic protease of Mycobacterium tuberculosis (MTB), as well as PfAp3Ase of Plasmodium falciparum. Therefore, cyclomarins are interesting lead structures for the development of drugs against tuberculosis and malaria. PMID:27241518

  14. Optimization of a siRNA Carrier Modified with a pH-Sensitive Cationic Lipid and a Cyclic RGD Peptide for Efficiently Targeting Tumor Endothelial Cells

    Tomoya Hada

    2015-09-01

    Full Text Available In recent years, anti-angiogenic therapy has attracted much interest because it is a versatile approach to treating most types of tumors, and therefore would be expected to be applicable for various cancers. Severe adverse events in patients treated with currently available anti-angiogenic therapeutics have, however, been reported, and these are caused by their inhibitory effects in normal tissue. To achieve an efficient anti-angiogenic therapy with minimal toxicity, a drug delivery system (DDS specific to tumor endothelial cells (TECs is needed. Cyclic RGD (cRGD is a well-known ligand against αVβ3 integrin that is expressed at high levels in the cell surface of TECs. To address this issue, we previously developed a cyclic RGD-equipped liposomal DDS (RGD-MEND in which small interfering RNA (siRNA was encapsulated. However, in the previous study, details of the preparation steps were not thoroughly examined. In this paper, to produce the most efficient delivery of therapeutic TECs, we explored optimum preparation conditions and components of the RGD-MEND. The cellular uptake and silencing ability of the RGD-MEND were investigated as a function of ligand density, poly(ethyleneglycol linker length, and lipid composition. As a result, a knockdown efficiency that was five-fold higher than that of the previously reported one (ED50, from 4.0 to 0.75 mg/kg was achieved.

  15. Cyclic Voltammetry.

    Evans, Dennis H.; And Others

    1983-01-01

    Cyclic voltammetry is a simple experiment that has become popular in chemical research because it can provide useful information about redox reactions in a form which is easily obtained and interpreted. Discusses principles of the method and illustrates its use in the study of four electrode reactions. (Author/JN)

  16. Clinical applications of 111-In-labelled granulocytes

    The authors studied 542 patients in detail who were referred over the past five years to the Nuclear Medicine Departments of either Stanford University or the VA Medical Center, Palo Alto, CA, for investigation of acute inflammatory disease. The results of the radionuclide imaging procedure (using 111-In-oxinate labelled granulocytes) were correlated to the clinical findings, X-ray studies, surgical procedures or other relevant evidence. The application of the 111-In-oxinate white cell scan in Nuclear Medicine has proved to be highly sensitive, specific and accurate. (orig.)

  17. Imaging tumors with peptide-based radioligands

    Behr, T. M.; Gotthardt, M.; Barth, A.; Behe, M. [Philipps-University of Marburg, Dept. of Nuclear Medicine, Marburg (Germany)

    2001-06-01

    Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over)-expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. In {sup 111}In-DTPA-(D-Phe{sup 1})-octreotide is the first and only radio peptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), it was postulated the expression of the corresponding (i.e. cholecystokinin (CCK-)-B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung. Indeed, {sup 111}In-labeled DTPA

  18. Design, preparation and characterization of cyclic RGDfK peptide modified poly(ethylene glycol)-block-poly(lactic acid) micelle for targeted delivery.

    Li, Caixia; Wang, Wenlong; Xi, Yuewei; Wang, Jiexin; Chen, Jian-Feng; Yun, Jimmy; Le, Yuan

    2016-07-01

    Molecular targeted cancer therapy is a promising strategy to overcome the lack of specificity of anticancer drug. While the binding of c(RGDfK) (cyclic Arginine-Glycine-Aspartic acid-Phenylalanine-Lysine) to αvβ3 over-expressed on tumor cell has been validated, the underlying interaction remains poorly understood. In this work, docking calculation was applied to investigate the interactions between c(RGDfK)/c(RGDfK)-PEG and αvβ3. The calculated results indicated that c(RGDfK) interacted with αvβ3 mainly by electrostatic interaction, stabilization interaction, and hydrophobic interaction. Conjugation of PEG chain to the c(RGDfK) weakened the binding affinity of c(RGDfK) to αvβ3. Accordingly, docetaxel(DTX)-loaded target micelles (c(RGDfK)-PEG-PLA/PEG-PLA/DTX) were designed, characterized and evaluated using HeLa cells. In vitro release studies demonstrated both target and non-target micelles displayed almost the same profiles, which best fit in Ritger-Peppas model. Cellular uptake and MTT studies revealed that the target micelles with the presence of c(RGDfK) were more efficiently taken up by HeLa cells and significantly improved the cytotoxicity compared to that of non-target micelles. Cell inhibition rate of target micelles was improved by 20% after 24h. Our findings suggest that target micelles may be a potential anticancer drug delivery system in the treatment of integrin αvβ3 over-expressed on tumor cell. PMID:27127057

  19. Comparison of Two Assays to Determine Anti-Citrullinated Peptide Antibodies in Rheumatoid Arthritis in relation to Other Chronic Inflammatory Rheumatic Diseases: Assaying Anti-Modified Citrullinated Vimentin Antibodies Adds Value to Second-Generation Anti-Citrullinated Cyclic Peptides Testing

    Miriam Lizette Díaz-Toscano

    2014-01-01

    Full Text Available Determination of anti-citrullinated peptide antibodies (ACPA plays a relevant role in the diagnosis of rheumatoid arthritis (RA. To date, it is still unclear if the use of several tests for these autoantibodies in the same patient offers additional value as compared to performing only one test. Therefore, we evaluated the performance of using two assays for ACPA: second-generation anti-citrullinated cyclic peptides antibodies (anti-CCP2 and anti-mutated citrullinated vimentin (anti-MCV antibodies for the diagnosis of RA. We compared three groups: RA (n=142, chronic inflammatory disease (CIRD, n=86, and clinically healthy subjects (CHS, n=56 to evaluate sensitivity, specificity, predictive values, and likelihood ratios (LR of these two assays for the presence of RA. A lower frequency of positivity for anti-CCP2 was found in RA (66.2% as compared with anti-MCV (81.0%. When comparing RA versus other CIRD, sensitivity increased when both assays were performed. This strategy of testing both assays had high specificity and LR+. We conclude that adding the assay of anti-MCV antibodies to the determination of anti-CCP2 increases the sensitivity for detecting seropositive RA. Therefore, we propose the use of both assays in the initial screening of RA in longitudinal studies, including early onset of undifferentiated arthritis.

  20. Cyclic Vitalism

    Halse, Sven

    2014-01-01

    taking such a unilateral view of what constituted a Vitalist concept of life. It could lead to a misunderstanding of Vitalist way of thinking, Rasch said, if the focus were only set upon the enthusiastic surplus, the worshipping of youth and health. To Vitalists, life is more than that. It is a totality...... that also encompasses notions of destruction, decay and death. “All life symbols in literature around 1900 are at the same time symbols of death”. (Rasch, W. 1967:24) Through the analyses of three poems, this article aims to show concrete examples of how cyclic Vitalist thinking is embedded in poetry...... of the era. The analyses include a further sub-categorisation to capture the different types of Life Force dealt with in the texts. By way of an introduction, Vitalism is discussed within the context of the scientific and social developments of the 19th Century....

  1. The status of rheumatoid factor and anti-cyclic citrullinated peptide antibody are not associated with the effect of anti-TNFα agent treatment in patients with rheumatoid arthritis: a meta-analysis.

    Qianwen Lv

    Full Text Available OBJECTIVES: This meta-analysis was conducted to investigate whether the status of rheumatoid factor (RF and anti-cyclic citrullinated peptide (anti-CCP antibody are associated with the clinical response to anti-tumor necrosis factor (TNF alpha treatment in rheumatoid arthritis (RA. METHODS: A systemic literature review was performed using the MEDLINE, SCOPUS, Cochrane Library, ISI Web of Knowledge, and Clinical Trials Register databases, and Hayden's criteria of quality assessment for prognostic studies were used to evaluate all of the studies. The correlation between the RF and anti-CCP antibody status with the treatment effect of anti-TNFα agents was analyzed separately using the Mantel Haenszel method. A fixed-effects model was used when there was no significant heterogeneity; otherwise, a random-effects model was applied. Publication bias was assessed using Egger's linear regression and a funnel plot. RESULTS: A total of 14 studies involving 5561 RA patients meeting the inclusion criteria were included. The overall analysis showed that the pooled relative risk for the predictive effects of the RF and anti-CCP antibody status on patient response to anti-TNFα agents was 0.98 (95% CI: 0.91-1.05, p=0.54 and 0.88 (95% CI: 0.76-1.03, p=0.11, respectively, with I(2 values of 43% (p=0.05 and 67% (p<0.01, respectively. Subgroup analyses of different anti-TNFα treatments (infliximab vs. etanercept vs. adalimumab vs. golimumab, response criteria (DAS28 vs. ACR20 vs. EULAR response, follow-up period (≥ 6 vs. <6 months, and ethnic group did not reveal a significant association for the status of RF and anti-CCP. CONCLUSIONS: Neither the RF nor anti-CCP antibody status in RA patients is associated with a clinical response to anti-TNFα treatment.

  2. Quantum Cyclic Code

    Dutta, Sagarmoy

    2010-01-01

    In this paper, we define and study \\emph{quantum cyclic codes}, a generalisation of cyclic codes to the quantum setting. Previously studied examples of quantum cyclic codes were all quantum codes obtained from classical cyclic codes via the CSS construction. However, the codes that we study are much more general. In particular, we construct cyclic stabiliser codes with parameters $[[5,1,3

  3. Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

    Gijs Koopmanschap

    2014-03-01

    Full Text Available In the recent past, the design and synthesis of peptide mimics (peptidomimetics has received much attention. This because they have shown in many cases enhanced pharmacological properties over their natural peptide analogues. In particular, the incorporation of cyclic constructs into peptides is of high interest as they reduce the flexibility of the peptide enhancing often affinity for a certain receptor. Moreover, these cyclic mimics force the molecule into a well-defined secondary structure. Constraint structural and conformational features are often found in biological active peptides. For the synthesis of cyclic constrained peptidomimetics usually a sequence of multiple reactions has been applied, which makes it difficult to easily introduce structural diversity necessary for fine tuning the biological activity. A promising approach to tackle this problem is the use of multicomponent reactions (MCRs, because they can introduce both structural diversity and molecular complexity in only one step. Among the MCRs, the isocyanide-based multicomponent reactions (IMCRs are most relevant for the synthesis of peptidomimetics because they provide peptide-like products. However, these IMCRs usually give linear products and in order to obtain cyclic constrained peptidomimetics, the acyclic products have to be cyclized via additional cyclization strategies. This is possible via incorporation of bifunctional substrates into the initial IMCR. Examples of such bifunctional groups are N-protected amino acids, convertible isocyanides or MCR-components that bear an additional alkene, alkyne or azide moiety and can be cyclized via either a deprotection–cyclization strategy, a ring-closing metathesis, a 1,3-dipolar cycloaddition or even via a sequence of multiple multicomponent reactions. The sequential IMCR-cyclization reactions can afford small cyclic peptide mimics (ranging from four- to seven-membered rings, medium-sized cyclic constructs or peptidic

  4. Detecting Anti-cyclic Citrullinated Peptide Antibody in Patients with Connective Tissue Diseases%抗环瓜氨酸肽抗体在混合性结缔组织病中的检测及意义

    尹耕; 岑筱敏; 杨闵; 谢其冰

    2011-01-01

    Objective To determine the clinical significance of anti-cyclic citrullinated peptide antibody (antiCCP) in mixed connective tissue diseases (MCTD).Methods Enzyme linked immunosorbent assay was performed to detect anti-CCP in 57 patients with MCTD, 78 with rheumatoid arthritis (RA), 64 with systemic lupus erythematosus (SLE), 56 with polymyositis/dermatomyositis (PM/DM), 53 with sjogren syndrome (SS) and with 33 systemic sclerosis (SSc).The association between anti-CCP and clinical features of MCTD was analysed.Results Anti-CCP was detected in 87.5% RA cases, 15.8% MCTD cases, 57.1% MCTD with RA cases, 14.1% SLE cases, 15.2% PM/DM cases, 18.9% SS cases and 9.1% SSc cases.Patients with RA (or MCTD with RA) were more likely to be anti-CCP positive than those without RA (P<0.05).The MCTD patients with positive anti-CCP had higher prevalence of RA and SS related manifestations than those MCTD patients with negative anti-CCP (P<0.05).The MCTD patients with RA had higher prevalence of RA-related symptoms, diffuse sclerosis and positive anti-CCP than those MCTD patients without RA (P<0.01).Significant deviation of disease spectrum was found in the MCTD patients with RA compared with the anti-CCP positive MCTD patients without RA.Conclusion High titer of anti-CCP in combination with RA, SLE and SSc manifestations in MCTD patients can be an indicator of erosive arthritis.%目的 探讨抗环瓜氨酸肽(CCP)抗体在混合性结缔组织病(MCTD)中的临床价值.方法 采用酶联免疫吸附法分别检测57例MCTD、78例类风湿关节炎(RA)、64例系统性红斑狼疮(SLE)、56例多发性肌炎/皮肌炎(PM/DM)、53例干燥综合征(SS)、33例系统性硬化病(SSc)患者血清的抗CCP抗体水平,分析比较抗CCP抗体与MCTD各种临床特征的关系.结果 抗CCP抗体在RA、MCTD、符合RA诊断标准的MCTD、SLE、PM/DM、SS、SSc患者中的阳性率分别为87.5%、15.8%、57.1%、14.1%、15.2%、18.9%、9.1%,其中RA组及符

  5. Imaging focal sites of bacterial infection in rats with indium-111-labeled chemotactic peptide analogs

    Four DTPA-derivatized chemotactic peptide analogs: ForNleLFNleYK-DTPA (P1), ForMLFNH(CH2)6NH-DTPA (P2), ForNleLFK(NH2)-DTPA (P3), and ForNleLFK-DTPA (P4), were synthesized and evaluated for in vitro bioactivity and receptor binding. The peptides were radiolabeled with 111In by transchelation and their biodistribution determined in rats at 5, 30, 60 and 120 min after injection. Localization at sites of infection was determined by scintillation camera imaging in animals with deep-thigh infection due to Escherichia coli. Images were recorded from 5 min to 2 hr after injection. All peptides maintained biologic activity (EC50 for O2-production by human PMN's: 3-150 nM) and the ability to bind to the oligopeptide chemoattractant receptor on human PMN's (EC50 for binding: 7.5-50 nM); biologic activity and receptor binding were highly correlated (r = 0.99). For all the peptides, blood clearance was rapid (half-lives: 21.5, 33.1, 31.6, and 28.7 min for P1, P2, P3, and P4, respectively). Biodistributions of the individual peptides were similar with low levels of accumulation in the heart, lung, liver, spleen, and gastrointestinal tract. In the kidney, P1 had much greater accumulation than other organs. All peptides yielded high quality images of the infection sites within 1 hr of injection. This study demonstrates that 111In-labeled chemotactic peptide analogs were effective agents for the external imaging of focal sites of infection

  6. Preparation of particulate cyclic citrullinated peptide antigens and optimization of experimental conditions%颗粒型环瓜氨酸肽抗原的制备及条件优化

    付琳; 裘宇容; 姜云飞; 夏佳音; 王海芳

    2013-01-01

    目的 探讨颗粒型环瓜氨酸肽抗原的制备方法,并对实验条件进行优化.方法 通过碳二亚胺交联法将人工合成的CCP与BSA共价偶联,使偶联产物蛋白大小在70-170 KD之间,经紫外吸收光谱鉴定偶联成功.采用碳二亚胺两步法将偶联成功的CCP与BSA复合物又与聚苯乙烯微球偶联,优化偶联条件,根据蛋白偶联量和偶联效率判断偶联效果.结果 (1)BSA与CCP偶联质量比为1∶1,EDC与NHS用量比为2∶3,偶联pH为6.0,BSA与CCP偶联可以达到较好的效果.BSA与CCP偶联产物在70 KD-170 KD之间,紫外吸收峰有明显左移.(2)微球与偶联蛋白的吸附效率随着EDC用量的增大而增大,当EDC用量达到7.5 mg/ml时,偶联蛋白最大效率达到63.66%.(3)随着偶联时间的延长,蛋白偶联微球的效率不断增加,在偶联时间为0.5-2 h内,偶联效率增加最快,当反应时间2 h后,反应趋于平衡.(4)对不同偶联反应pH值条件进行筛选,pH为7.5时偶联效果最好,pH7.0-8.0为适宜偶联的pH范围.结论 CCP-BSA偶联产物蛋白与胶乳颗粒偶联,当EDC浓度为7.5 mg/ml,偶联时间为2 h,反应PH值为7.5,蛋白偶联效率可达到63.66%.%Objective To investigate the preparation method of particulate cyclic citrullinated peptide antigens,and optimize the experimental conditions. Methods The artificially synthesized CCP was covalent coupled with BSA by the method of carbodiimide cross linking,and the protein sizes of1 the coupled products were between 70 to 170 KD. The covalent coupling was tested by ultraviolet absorption spectrum. Then the successful coupling complex of BSA and CCP were covalently coupled to the microspheres,and the coupling conditions were optimized. The covalent coupling effect was determined according to the protein coupling quantity and the coupling efficiency. Results (1) When the mass ra tio of BSA and CCP was 1 : 1,the ratio of EDC and NHS was 2 : 3,and the pH of coupling was 6.0,the coupling result of BSA

  7. Cyclic phosphonium ionic liquids

    Sharon I. Lall-Ramnarine

    2014-01-01

    Full Text Available Ionic liquids (ILs incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonylamide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners.

  8. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Berhanu, Workalemahu M; Ibrahim, Mohamed A; Pillai, Girinath G; Oliferenko, Alexander A; Khelashvili, Levan; Jabeen, Farukh; Mirza, Bushra; Ansari, Farzana Latif; ul-Haq, Ihsan; El-Feky, Said A

    2012-01-01

    Summary The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium. PMID:23019443

  9. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Workalemahu M. Berhanu

    2012-07-01

    Full Text Available The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium.

  10. No Arithmetic Cyclic Quadrilaterals

    Beauregard, Raymond A.

    2006-01-01

    A quadrilateral is arithmetic if its area is an integer and its sides are integers in an arithmetic progression, and it is cyclic if it can be inscribed in a circle. The author shows that no quadrilateral is both arithmetic and cyclic.

  11. Affordable Cyclic Voltammetry

    Stewart, Greg; Kuntzleman, Thomas S.; Amend, John R.; Collins, Michael J.

    2009-01-01

    Cyclic voltammetry is an important component of the undergraduate chemical curriculum. Unfortunately, undergraduate students rarely have the opportunity to conduct experiments in cyclic voltammetry owing to the high cost of potentiostats, which are required to control these experiments. By using MicroLab data acquisition interfaces in conjunction…

  12. Asymptotic cyclic cohomology

    Puschnigg, Michael

    1996-01-01

    The aim of cyclic cohomology theories is the approximation of K-theory by cohomology theories defined by natural chain complexes. The basic example is the approximation of topological K-theory by de Rham cohomology via the classical Chern character. A cyclic cohomology theory for operator algebras is developed in the book, based on Connes' work on noncommutative geometry. Asymptotic cyclic cohomology faithfully reflects the basic properties and features of operator K-theory. It thus becomes a natural target for a Chern character. The central result of the book is a general Grothendieck-Riemann-Roch theorem in noncommutative geometry with values in asymptotic cyclic homology. Besides this, the book contains numerous examples and calculations of asymptotic cyclic cohomology groups.

  13. Selective inhibition by a synthetic hirudin peptide of fibrin-dependent thrombosis in baboons

    Cadroy, Y.; Hanson, S.R.; Harker, L.A. (Emory Univ., Atlanta, GA (United States)); Maraganore, J.M. (Biogen Inc., Cambridge, MA (United States))

    1991-02-15

    To determine the importance of the thrombin substrate recognition exosite for fibrinogen binding in the formation of both arterial and venous thrombi the authors evaluated the antithrombotic effects of the tyrosine-sulfated dodecapeptide from residues 53-64 of hirudin (H peptide) in a nonhuman primate model. This peptide was studied because it inhibits thrombin cleavages of fibrinogen by simple competition without blocking enzyme catalytic-site function. When an exteriorized arteriovenous access shunt model was used in baboons (Papio anubis), thrombus formation was induced by placing a thrombogenic device made of (i) a segment of tubing coated covalently with type I collagen, which generated platelet-rich thrombi under arterial flow conditions, and (ii) two subsequent annular regions of flow expansion that produced fibrin-rich thrombi typically associated with venous valves and veins. Thrombus formation was quantified by measurements of {sup 111}In-labeled platelet and {sup 125}I-labeled fibrinogen deposition in both arterial-flow and venous-flow portions of the device. These finding suggest that, by competitive inhibition of fibrinogen binding to thrombin, fibrin-rich venous-type thrombus formation may be selectively prevented. This strategy may be therapeutically attractive for preserving normal platelet function when conventional anticoagulant therapy is contraindicated.

  14. Selective inhibition by a synthetic hirudin peptide of fibrin-dependent thrombosis in baboons

    To determine the importance of the thrombin substrate recognition exosite for fibrinogen binding in the formation of both arterial and venous thrombi the authors evaluated the antithrombotic effects of the tyrosine-sulfated dodecapeptide from residues 53-64 of hirudin (H peptide) in a nonhuman primate model. This peptide was studied because it inhibits thrombin cleavages of fibrinogen by simple competition without blocking enzyme catalytic-site function. When an exteriorized arteriovenous access shunt model was used in baboons (Papio anubis), thrombus formation was induced by placing a thrombogenic device made of (i) a segment of tubing coated covalently with type I collagen, which generated platelet-rich thrombi under arterial flow conditions, and (ii) two subsequent annular regions of flow expansion that produced fibrin-rich thrombi typically associated with venous valves and veins. Thrombus formation was quantified by measurements of 111In-labeled platelet and 125I-labeled fibrinogen deposition in both arterial-flow and venous-flow portions of the device. These finding suggest that, by competitive inhibition of fibrinogen binding to thrombin, fibrin-rich venous-type thrombus formation may be selectively prevented. This strategy may be therapeutically attractive for preserving normal platelet function when conventional anticoagulant therapy is contraindicated

  15. Synthesis of Cyclic Antifreeze Glycopeptide and Glycopeptoids and Their Ice Recrystallization Inhibition Activity

    Ahn, Mija; Murugan, Ravichandran N.; Bang, Jeong Kyu; Kim, Hak Jun [Korea Basic Science Institute, Daejeon (Korea, Republic of); Shin, Song Yub [Chousn Univ., Gwangju (Korea, Republic of); Kim, Eunjung; Lee, Jun Hyuck [Korea Polar Research Institute, Incheon (Korea, Republic of)

    2012-11-15

    Until now, few groups reported the antifreeze activity of cyclic glycopeptides; however, the tedious synthetic procedure is not amenable to study the intensive structure activity relationship. A series of N-linked cyclic glycopeptoids and glycopeptide have been prepared to evaluate antifreeze activity as a function of peptide backbone cyclization and methyl stereochemical effect on the rigid Thr position. This study has combined the cyclization protocol with solid phase peptide synthesis and obtained significant quantities of homogeneous cyclic glycopeptide and glycopeptoids. Analysis of antifreeze activity revealed that our cyclic peptide demonstrated RI activity while cyclic glycopeptoids showed no RI activity. These results suggest that the subtle changes in conformation and Thr orientation dramatically influence RI activity of N-linked glycopeptoids.

  16. Genetics Home Reference: cyclic neutropenia

    ... Understand Genetics Home Health Conditions cyclic neutropenia cyclic neutropenia Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Cyclic neutropenia is a disorder that causes frequent infections and ...

  17. Antimicrobial Peptides from Plants

    Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang

    2015-01-01

    Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629

  18. Antimicrobial Peptides from Plants

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  19. EXPRESSED PROTEIN LIGATION. A NEW TOOL FOR THE BIOSYNTHESIS OF CYCLIC POLYPEPTIDES

    Kimura, R; Camarero, J A

    2004-11-11

    The present paper reviews the use of expressed protein ligation for the biosynthesis of backbone cyclic polypeptides. This general method allows the in vivo and in vitro biosynthesis of cyclic polypeptides using recombinant DNA expression techniques. Biosynthetic access to backbone cyclic peptides opens the possibility to generate cell-based combinatorial libraries that can be screened inside living cells for their ability to attenuate or inhibit cellular processes.

  20. Cyclical budget balance measurement

    C. AUDENIS; C. PROST

    2000-01-01

    Government balances are often adjusted for changes in economic activity in order to draw a clearer picture of the underlying fiscal situation and to use this as a guide to fiscal policy analysis. International organisations estimate the cyclical component of economic activity by the current level of the output gap. Using elasticities of tax and public expenditures to GDP, they compute the cyclical part of budget balance. The structural budget balance is defined as the remainder. Our approach ...

  1. Cyclic steps on ice

    Yokokawa, M.; Izumi, N.; Naito, K.; Parker, G.; Yamada, T.; Greve, R.

    2016-05-01

    Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice caps of Mars have been interpreted to be cyclic steps formed by katabatic wind blowing over ice. Cyclic steps are relatives of upstream-migrating antidunes. Cyclic step formation on ice is not only a mechanical but also a thermodynamic process. There have been very few studies on the formation of either cyclic steps or upstream-migrating antidunes on ice. In this study, we performed flume experiments to reproduce cyclic steps on ice by flowing water, and found that trains of steps form when the Froude number is larger than unity. The features of those steps allow them to be identified as ice-bed analogs of cyclic steps in alluvial and bedrock rivers. We performed a linear stability analysis and obtained a physical explanation of the formation of upstream-migrating antidunes, i.e., precursors of cyclic steps. We compared the results of experiments with the predictions of the analysis and found the observed steps fall in the range where the analysis predicts interfacial instability. We also found that short antidune-like undulations formed as a precursor to the appearance of well-defined steps. This fact suggests that such antidune-like undulations correspond to the instability predicted by the analysis and are precursors of cyclic steps.

  2. PET imaging of {alpha}{sub v}{beta}{sub 3} integrin expression in tumours with {sup 68}Ga-labelled mono-, di- and tetrameric RGD peptides

    Dijkgraaf, Ingrid; Franssen, Gerben M.; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); Yim, Cheng-Bin [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); Utrecht University, Department of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht (Netherlands); Schuit, Robert C. [VU University Medical Centre, Department of Nuclear Medicine and PET Research, P.O. Box 7057, Amsterdam (Netherlands); Luurtsema, Gert [University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, P.O. Box 30.001, Groningen (Netherlands); Liu, Shuang [Purdue University, School of Health Sciences, West Lafayette, IN (United States)

    2011-01-15

    Due to the restricted expression of {alpha}{sub v}{beta}{sub 3} in tumours, {alpha}{sub v}{beta}{sub 3} is considered a suitable receptor for tumour targeting. In this study the {alpha}{sub v}{beta}{sub 3}-binding characteristics of {sup 68}Ga-labelled monomeric, dimeric and tetrameric RGD peptides were determined and compared with their {sup 111}In-labelled counterparts. A monomeric (E-c(RGDfK)), a dimeric (E-[c(RGDfK)]{sub 2}) and a tetrameric (E{l_brace}E[c(RGDfK)]{sub 2}{r_brace}{sub 2}) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with {sup 68}Ga. In vitro {alpha}{sub v}{beta}{sub 3}-binding characteristics were determined in a competitive binding assay. In vivo {alpha}{sub v}{beta}{sub 3}-targeting characteristics of the compounds were assessed in mice with subcutaneously growing SK-RC-52 xenografts. In addition, microPET images were acquired using a microPET/CT scanner. The IC{sub 50} values for the Ga(III)-labelled DOTA-E-c(RGDfK), DOTA-E-[c(RGDfK)]{sub 2} and DOTA-E{l_brace}E[c(RGDfK)]{sub 2}{r_brace}{sub 2} were 23.9 {+-} 1.22, 8.99 {+-} 1.20 and 1.74 {+-} 1.18 nM, respectively, and were similar to those of the In(III)-labelled mono-, di- and tetrameric RGD peptides (26.6 {+-} 1.15, 3.34 {+-} 1.16 and 1.80 {+-} 1.37 nM, respectively). At 2 h post-injection, tumour uptake of the {sup 68}Ga-labelled mono-, di- and tetrameric RGD peptides (3.30 {+-} 0.30, 5.24 {+-} 0.27 and 7.11 {+-} 0.67%ID/g, respectively) was comparable to that of their {sup 111}In-labelled counterparts (2.70 {+-} 0.29, 5.61 {+-} 0.85 and 7.32 {+-} 2.45%ID/g, respectively). PET scans were in line with the biodistribution data. On all PET scans, the tumour could be clearly visualised. The integrin affinity and the tumour uptake followed the order of DOTA-tetramer > DOTA-dimer > DOTA-monomer. The {sup 68}Ga-labelled tetrameric RGD peptide has excellent characteristics for imaging of {alpha}{sub v} {beta}{sub 3} expression with PET. (orig.)

  3. PET imaging of αvβ3 integrin expression in tumours with 68Ga-labelled mono-, di- and tetrameric RGD peptides

    Due to the restricted expression of αvβ3 in tumours, αvβ3 is considered a suitable receptor for tumour targeting. In this study the αvβ3-binding characteristics of 68Ga-labelled monomeric, dimeric and tetrameric RGD peptides were determined and compared with their 111In-labelled counterparts. A monomeric (E-c(RGDfK)), a dimeric (E-[c(RGDfK)]2) and a tetrameric (E{E[c(RGDfK)]2}2) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with 68Ga. In vitro αvβ3-binding characteristics were determined in a competitive binding assay. In vivo αvβ3-targeting characteristics of the compounds were assessed in mice with subcutaneously growing SK-RC-52 xenografts. In addition, microPET images were acquired using a microPET/CT scanner. The IC50 values for the Ga(III)-labelled DOTA-E-c(RGDfK), DOTA-E-[c(RGDfK)]2 and DOTA-E{E[c(RGDfK)]2}2 were 23.9 ± 1.22, 8.99 ± 1.20 and 1.74 ± 1.18 nM, respectively, and were similar to those of the In(III)-labelled mono-, di- and tetrameric RGD peptides (26.6 ± 1.15, 3.34 ± 1.16 and 1.80 ± 1.37 nM, respectively). At 2 h post-injection, tumour uptake of the 68Ga-labelled mono-, di- and tetrameric RGD peptides (3.30 ± 0.30, 5.24 ± 0.27 and 7.11 ± 0.67%ID/g, respectively) was comparable to that of their 111In-labelled counterparts (2.70 ± 0.29, 5.61 ± 0.85 and 7.32 ± 2.45%ID/g, respectively). PET scans were in line with the biodistribution data. On all PET scans, the tumour could be clearly visualised. The integrin affinity and the tumour uptake followed the order of DOTA-tetramer > DOTA-dimer > DOTA-monomer. The 68Ga-labelled tetrameric RGD peptide has excellent characteristics for imaging of αv β3 expression with PET. (orig.)

  4. Cyclic polymers from alkynes

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  5. PEPTIDE TARGETING OF PLATINUM ANTI-CANCER DRUGS

    Ndinguri, Margaret W.; Solipuram, Rajasree; Gambrell, Robert P.; Aggarwal, Sita; Hansel, William; Hammer, Robert P.

    2009-01-01

    Besides various side effects caused by platinum anticancer drugs, they are not efficiently absorbed by the tumor cells. Two Pt-peptide conjugates; cyclic mPeg-CNGRC-Pt (7) and cyclic mPeg-CNGRC-Pten (8) bearing the Asn-Gly-Arg (NGR) targeting sequence, a malonoyl linker and low molecular weight miniPEG groups have been synthesized. The platinum ligand was attached to the peptide via the carboxylic end of the malonate group at the end of the peptide. The pegylated peptide is non toxic and high...

  6. Peptide dendrimers

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788. ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  7. Cysteine and arginine-rich peptides as molecular carriers.

    Shirazi, Amir Nasrolahi; El-Sayed, Naglaa Salem; Mandal, Dindayal; Tiwari, Rakesh K; Tavakoli, Kathy; Etesham, Matthew; Parang, Keykavous

    2016-01-15

    A number of linear and cyclic peptides containing alternative arginine and cysteine residues, namely linear (CR)3, linear (CR)4, linear (CR)5, cyclic [CR]4, and cyclic [CR]5, were synthesized. The peptides were evaluated for their ability to deliver two molecular cargos, fluorescence-labeled cell-impermeable negatively charged phosphopeptide (F'-GpYEEI) and fluorescence-labeled lamivudine (F'-3TC), intracellularly in human leukemia cancer (CCRF-CEM) cells. We investigated the role of cyclization and the number of amino acids in improving the transporting ability of the peptides. The flow cytometry studies suggested that the synthesized peptides were able to work efficiently as transporters for both cargos. Among all compounds, cyclic [CR]4 was found to be the most efficient peptide in transporting the cargo into cells. For instance, the cellular uptake of F'-3TC (5μM) and F'-GpYEEI (5μM) was enhanced by 16- and 20-fold, respectively, in the presence of cyclic [CR]4 compared to that of the parent compound alone. The mechanism of F'-GpYEEI uptake by cells was found to be energy-independent. The results showed that the number of amino acids and their cyclic nature can impact the efficiency of the peptide in transporting the molecular cargos. PMID:26631317

  8. 抗CCP抗体和RF联检在RA诊疗中的临床价值%Clinical Value of Combined Detection of Serum Anti-Cyclic Citrullinated Peptide Antibody(Anti-CCP Ab)and Rheumatoid Factor(RF)in Diagnosis of Rheumatoid Arthritis

    葛文亮

    2010-01-01

    目的:研究抗环瓜氨酸肽(anti-cyclic citrullinated peptide,Anti-CCP)(抗CCP抗体)和RF的检测在类风湿关节炎(RA)诊疗中的临床价值.方法:分别用酶联免疫吸附试验(ELISA)、BeckMan全自动蛋白分析仪同时检测早期RA组(病程<1年)42例,RA组(病程>1年)40例,非RA对照组40例患者血清抗CCP抗体和RF.结果:早期RA组、RA组的抗CCP抗体、RF阳性率显著高于非RA对照组(P<0.05)RA组抗CCP水平显著高于早期RA组(P<0.01),两者RF无显著差别(P>0.05).RA组与早期RA组CCP抗体与RF二者无相关性.结论:联检抗CCP抗体、RF有助于类风湿的早期诊断和预测病情的进展.

  9. Synthesis of peptide .alpha.-thioesters

    Camarero, Julio A.; Mitchell, Alexander R.; De Yoreo, James J.

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  10. On Expanded Cyclic Codes

    Wu, Yingquan

    2008-01-01

    The paper has a threefold purpose. The first purpose is to present an explicit description of expanded cyclic codes defined in $\\GF(q^m)$. The proposed explicit construction of expanded generator matrix and expanded parity check matrix maintains the symbol-wise algebraic structure and thus keeps many important original characteristics. The second purpose of this paper is to identify a class of constant-weight cyclic codes. Specifically, we show that a well-known class of $q$-ary BCH codes excluding the all-zero codeword are constant-weight cyclic codes. Moreover, we show this class of codes achieve the Plotkin bound. The last purpose of the paper is to characterize expanded cyclic codes utilizing the proposed expanded generator matrix and parity check matrix. We analyze the properties of component codewords of a codeword and particularly establish the precise conditions under which a codeword can be represented by a subbasis. With the new insights, we present an improved lower bound on the minimum distance of...

  11. Cyclic Voltammetry Experiment.

    Van Benschoten, James J.; And Others

    1983-01-01

    Describes a three-part experiment designed to introduce cyclic voltammetry to graduate/undergraduate students. Part 1 demonstrates formal reduction potential, redox electron transfer, diffusion coefficient, and electrochemical reversibility. Part 2 investigates electrochemical behavior of acetaminophen. Part 3 examines such experimental variables…

  12. Graphical Cyclic Permutation Groups

    Grech, Mariusz

    2012-01-01

    We establish conditions for a permutation group generated by a single permutation of a prime power order to be an automorphism group of a graph or an edge-colored graph. This corrects and generalizes the results of the two papers on cyclic permutation groups published in 1978 and 1981 by S. P. Mohanty, M. R. Sridharan, and S. K. Shukla.

  13. Cyclic Voltammograms from First Principles

    Karlberg, Gustav; Jaramillo, Thomas; Skulason, Egill; Rossmeisl, Jan; Bligaard, Thomas; Nørskov, Jens Kehlet

    2007-01-01

    Cyclic voltammetry is a fundamental experimental tool for characterizing electrochemical surfaces. Whereas cyclic voltammetry is widely used within the field of electrochemistry, a way to quantitatively and directly relate the cyclic voltammogram to ab initio calculations has been lacking, even for...

  14. The cyclic universe

    Chung Ding Yu

    2001-01-01

    The cyclic universe model is a modification of the ekpyrotic universe and the pyrotechnic universe models. The cyclic universe goes through the six transitions: the triplet universe, the inflation, the big bang, the quintessence, the big crush, and the deflation transitions. The universe starts with eleven dimensional space-time with two boundary 9-branes separated by a finite gap spanning an intervening bulk volume. The triplet transition starts when the bulk 9-brane is generated from the hidden boundary 9-brane, and collides with the pre-observable 9-brane. The collision starts the inflation transition. The collision is the brane dimensional interference mixing between the pre-observable 9-brane and the bulk 9-brane. The results are the mixed branes (combined brane dimensions), the internal space (cancelled brane dimensions), the bulk space, 3-brane vacuum, and cosmic radiation. Cosmic radiation generated during the inflation leads to the big bang. Meanwhile, the hidden brane undergoes stepwise fractionaliz...

  15. Dynamics of cyclic machines

    Vulfson, Iosif

    2015-01-01

    This book focuses on modern methods of oscillation analysis in machines, including cyclic action mechanisms (linkages, cams, steppers, etc.). It presents schematization techniques and mathematical descriptions of oscillating systems, taking into account the variability of the parameters and nonlinearities, engineering evaluations of dynamic errors, and oscillation suppression methods. The majority of the book is devoted to the development of new methods of dynamic analysis and synthesis for cyclic machines that form regular oscillatory systems with multiple duplicate modules.  There are also sections examining aspects of general engineering interest (nonlinear dissipative forces, systems with non-stationary constraints, impacts and pseudo-impacts in clearances, etc.)  The examples in the book are based on the widely used results of theoretical and experimental studies as well as engineering calculations carried out in relation to machines used in the textile, light, polygraphic and other industries. Particu...

  16. [Brain natriuretic peptide].

    La Villa, G; Lazzeri, C; Fronzaroli, C; Franchi, F; Gentilini, P

    1995-01-01

    Brain natriuretic peptide (BNP) is a cardiac hormone with a spectrum of activities quite similar to those of atrial natriuretic peptide (ANP), including diuretic, natriuretic, hypotensive and smooth muscle relaxant activities. These effects are due to the stimulation of guanylate cyclase-linked natriuretic peptide receptors, leading to an increase in cyclic GMP concentration in target cells. BNP has a lower affinity than ANP for C (clearance) receptors, and is less susceptible to degradation by neutral endopeptidase-24.11, resulting in a longer half-life. In the kidney, BNP increases the glomerular filtration rate and inhibits sodium reabsorption in the distal tubule. It also inhibits the release of renin and aldosterone. Unlike ANP, produced by the atria, BNP is mainly synthesized and released into circulation by the left ventricle and is therefore influenced by stimuli involving this cardiac chamber, such as an increase in arterial pressure, left ventricular hypertrophy and dilation. Plasma BNP levels are very low in healthy subjects, and respond modestly, although significantly to physiological stimuli such as changes in posture or sodium intake. In contrast, plasma BNP concentrations increase in disease states such as cirrhosis with ascites, hypertension, chronic renal failure, acute myocardial infarction and congestive heart failure. In the latter condition, plasma BNP concentration is a reliable prognostic index. Evidence obtained by administering BNP to healthy subjects and hypertensive patients suggests that BNP, at physiological and pathophysiological plasma concentrations, markedly influences cardiovascular homeostasis, mainly due to its effects on sodium excretion and the renin-aldosterone axis. PMID:8718658

  17. Cyclical Unemployment, Structural Unemployment

    Peter A. Diamond

    2013-01-01

    Whenever unemployment stays high for an extended period, it is common to see analyses, statements, and rebuttals about the extent to which the high unemployment is structural, not cyclical. This essay views the Beveridge Curve pattern of unemployment and vacancy rates and the related matching function as proxies for the functioning of the labor market and explores issues in that proxy relationship that complicate such analyses. Also discussed is the concept of mismatch.

  18. Accelerated cyclic corrosion tests

    Prošek T.

    2016-01-01

    Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS) test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical p...

  19. Endothelin and a Ca2+ ionophore raise cyclic GMP levels in a neuronal cell line via formation of nitric oxide.

    Reiser, G.

    1990-01-01

    1. The vasoconstrictor peptide endothelin-1 caused a fast, transient rise in guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels in a neuronal cell line (mouse neuroblastoma x rat glioma hybrid cells 108CC15). The mechanism of activation of guanylate cyclase by endothelin-1 was investigated. The endothelin-1-induced rise depended on the release of internal Ca2+. 2. The stimulation of cyclic GMP synthesis induced by endothelin-1 was suppressed after preincubating the cells in medium conta...

  20. Exploiting Protected Maleimides to Modify Oligonucleotides, Peptides and Peptide Nucleic Acids

    Clément Paris

    2015-04-01

    Full Text Available This manuscript reviews the possibilities offered by 2,5-dimethylfuran-protected maleimides. Suitably derivatized building blocks incorporating the exo Diels-Alder cycloadduct can be introduced at any position of oligonucleotides, peptide nucleic acids, peptides and peptoids, making use of standard solid-phase procedures. Maleimide deprotection takes place upon heating, which can be followed by either Michael-type or Diels-Alder click conjugation reactions. However, the one-pot procedure in which maleimide deprotection and conjugation are simultaneously carried out provides the target conjugate more quickly and, more importantly, in better yield. This procedure is compatible with conjugates involving oligonucleotides, peptides and peptide nucleic acids. A variety of cyclic peptides and oligonucleotides can be obtained from peptide and oligonucleotide precursors incorporating protected maleimides and thiols.

  1. The tRNA-Dependent Biosynthesis of Modified Cyclic Dipeptides

    Giessen, Tobias W.; Mohamed A. Marahiel

    2014-01-01

    In recent years it has become apparent that aminoacyl-tRNAs are not only crucial components involved in protein biosynthesis, but are also used as substrates and amino acid donors in a variety of other important cellular processes, ranging from bacterial cell wall biosynthesis and lipid modification to protein turnover and secondary metabolite assembly. In this review, we focus on tRNA-dependent biosynthetic pathways that generate modified cyclic dipeptides (CDPs). The essential peptide bond...

  2. Development of an 111In-labeled dihydropyridine complex for L-type calcium channel imaging

    [111In]-DTPA-Amlodipine complex ([111In]-DTPA-AMLO) was prepared starting high purity [111In]indium chloride and conjugated DTPA-AMLO in 30 min at room temperature in acetate buffer in high radiochemical purity (>99 %, RTLC/HPLC; specific activity: 8-10 GBq/mmol). The log P, stability, biodistribution studies and imaging studies in untreated and amlodipine-pretreated rats were determined. The tracer is mostly washed out through kidneys as expected for a dihydropyridine compound. Blocking studies demonstrated high specific binding of the tracer in calcium channel-rich organs including intestine, heart and colon. SPECT images fully supported above results in normal and treated rats. (author)

  3. Radioimmunoimaging of human colon carcinoma xenografts in nude mice with 111In-labelled monoclonal antibody

    A nude mouse model bearing human colon carcinoma xenograft from human fresh surgical specimens was established. The anti-colon carcinoma monoclonal antibody 2C10 was labelled with 111In using bifunctional chelating agent DTPA. The labelled antibodies were injected intraperitoneally into the tumor-bearing mice. The tissue distribution of labelled antibody was studied and whole body scintigraphies were obtained with a γ camera at different times. 96 hours after administration, the tumor to muscle ratio was 10.48, tumor to blood ratio 3.94 and tumor to liver ratio 1.58. There were significant difference in T/N ratio between animals receiving the specific antibody and labelled unrelated mouse IgG. Imaging showed clear tumor pictures in all animals receiving the specific McAb, while the two animals receiving unrelated mouse IgG showed negative imaging

  4. Indium (111In)-labelled platelets in the diagnosis of renal transplant rejection: preliminary findings

    Eleven patients with recent kidney transplants have undergone serial pelvic imaging after autologous platelet labelling with indium-111. Rejection was accompanied by marked platelet deposition in the graft, whereas acute tubular necrosis was characterized by minimal platelet accumulation. The method has been quantified by comparing counts over the graft to counts from a similar area on the opposite site, and appears to distinguish between the two main causes of renal failure after transplantation. In addition, complications of transplant surgery may be demonstrated. (author)

  5. 111In labelled platelets in the diagnosis of kidney transplant rejection

    Scintigraphy (employing Tc-99m-DTPA and/or I-131-hippuran) is often performed in post-operative management to determine perfusion and function of a kidney graft. Although lymphocytes and monocytes are predominantly found in the interstitial tissue of the rejection graft, accumulation of neutrophilic granulocytes and platelets also occurs. The availability of a very efficient labelling technique for these latter cells with In-111 oxinate prompted the authors to investigate the role of granulocytes and platelets in graft rejection, particularly in the early stages of that process. The results with granulocytes, published elsewhere, showed just a slightly increased accumulation of apparently viable granulocytes during a florid kidney graft rejection and could thus not sustain the preliminary results of Frick et al. that these cells might be a useful tool in the diagnosis of graft rejection. Therefore, it was decided to proceed the study using autologous In-111 labelled thrombocytes, the results of which are reported in this paper. Compared to the 'classical' cell-marker Cr-51, In-111 permits more photons per mrad absorbed dose. Moreover, the gamma energies emitted by the latter radionuclide (173 and 247 keV) makes it very suitable for in vivo detection with a gamma camera. Finally, the radioactive half-life of In-111 (2.8 days) combines favourably with the biological half-life of both granulocytes (4-6 hours) and thromocytes (4 days). (Auth.)

  6. /sup 111/In labelled platelets in the diagnosis of kidney transplant rejection

    Hardeman, M.R.; Vreeken, J.; Surachno, S.; ten Veen, J.H.; Wilmink, J.M.; van Royen, E.A.; van der Schoot, J.B. (Amsterdam Univ. (Netherlands). Academisch Ziekenhuis)

    1982-01-01

    Scintigraphy (employing Tc-99m-DTPA and/or I-131-hippuran) is often performed in post-operative management to determine perfusion and function of a kidney graft. Although lymphocytes and monocytes are predominantly found in the interstitial tissue of the rejection graft, accumulation of neutrophilic granulocytes and platelets also occurs. The availability of a very efficient labelling technique for these latter cells with In-111 oxinate prompted the authors to investigate the role of granulocytes and platelets in graft rejection, particularly in the early stages of that process. The results with granulocytes, published elsewhere, showed just a slightly increased accumulation of apparently viable granulocytes during a florid kidney graft rejection and could thus not sustain the preliminary results of Frick et al. that these cells might be a useful tool in the diagnosis of graft rejection. Therefore, it was decided to proceed with the study using autologous In-111 labelled thrombocytes, the results of which are reported in this paper. Compared to the 'classical' cell-marker Cr-51, In-111 permits more photons per mrad absorbed dose. Moreover, the gamma energies emitted by the latter radionuclide (173 and 247 keV) makes it very suitable for in vivo detection with a gamma camera. Finally, the radioactive half-life of In-111 (2.8 days) combines favourably with the biological half-life of both granulocytes (4-6 hours) and thromocytes (4 days).

  7. Use of 111In-labeled autologous leukocytes to image an abdominal abscess in a horse

    Indium 111-labeled autologous leukocytes were used to image an abdominal abscess in a horse with a palpable abdominal mass and history of Streptococcus equi infection. A focal area of radioactivity was identified in the location corresponding to the abscess. Imaging of this focal uptake was optimal 48 hours after injection. Similar scans obtained in 2 clinically normal horses revealed no evidence of focal radioactivity in this region. The cell labeling procedure gave acceptable labeling efficiency (87.5%) but an excessive number of damaged WBC, resulting in persistent lung radioactivity on all images. No adverse effects were noted. Radiation measured in the horse and its excreta were well within acceptable limits

  8. Radioimmunodetection with 111In-labeled monoclonal antibody Nd2 in patients with pancreatic cancer

    This report summarizes results from an initial clinical evaluation of radioimmunodetection (RAID) in patients with pancreatic cancer using murine monoclonal antibody Nd2, directed against mucins from pancreatic cancer. Nd2 (2 mg) was labeled with 111In (2 mCi) and injected into 19 patients suspected of having pancreatic cancer. Planar scintigrams were taken 3 days post-infusion. As for final diagnoses after surgery, 14 cases were pancreatic cancer, and one case each was chronic pancreatitis, neurilemmoma, islet cell carcinoma, cholangioma, and apparent absence of suspected recurrent lesion of pancreatic cancer. Of 14 patients with pancreatic cancer, RAID was positive in 10 cases (71.4%). Cases other than pancreatic cancer were all negative, so the specificity was 100%. These results demonstrate that RAID using 111In-Nd2 can be useful in differentiating exocrine pancreatic cancer from benign conditions and other types of carcinomas in the pancreatoduodenal regions. (author)

  9. An Early Cyclic Universe

    Duhe, William; Biswas, Tirthibir

    2014-03-01

    We provide a comprehensive numerical study of the Emergent Cyclic Inflation scenario. This is a scenario where instead of traditional monotonic slow roll inflation, the universe expands over numerous short asymmetric cycles due to the production of entropy via interactions among different species. This is one of the very few scenarios of inflation which provides a nonsingular geodesically complete space-time and does not require any ``reheating'' mechanism. A special thanks to Loyola University for an excellent community to help this project grow.

  10. Tumour uptake of the radiolabelled somatostatin analogue [DOTA0,TYR3]octreotide is dependent on the peptide amount

    Radiolabelled tumour receptor-binding peptides can be used for in vivo scintigraphic imaging. Recently, the somatostatin analogue [Tyr3]octreotide (d-Phe-c(Cys-Tyr-d-Trp-Lys-Thr-Cys)-Thr(ol)) was derivatized with the chelator DOTA (tetra-azacyclododecane-tetra-acetic acid), enabling stable radiolabelling with both the high-energy beta particle-emitter yttrium-90 and the Auger electron-emitter indium-111. The thus produced radiolabelled compounds are promising for peptide receptor radionuclide therapy. Our previous in vitro and in vivo (rat) experiments with these radiolabelled compounds showed favourable binding and biodistribution characteristics with high uptake and retention in the target organs. We also demonstrated receptor-specific, time- and temperature-dependent internalization of radiolabelled [DOTA0,Tyr3]octreotide in somatostatin receptor subtype 2 (sst2)-positive rat pancreatic tumour cell lines. In this study we have investigated the effects of differences in the amount of injected peptide on tissue distribution of 111In-labelled [DOTA0,Tyr3]octreotide in normal, i.e. non-tumour-bearing, and CA20948 tumour-bearing rats. This was done in order to find the amount of peptide at which the highest uptake in target tissues is achieved, and thereby to increase the potential of radionuclide therapy while simultaneously ensuring the lowest possible radiotoxicity in normal organs. Uptake of radiolabelled [DOTA0,Tyr3]octreotide in sst2-positive organs showed different bell-shaped functions of the amount of injected peptide, being highest at 0.05 (adrenals), 0.05-0.1 (pituitary and stomach) and 0.25 (pancreas) μg. Uptake in the tumour was highest at 0.5 μg injected peptide. The highest uptake was found at peptide amounts that were lower than those reported for [111In-DTPA0]octreotide (d-Phe-c(Cys-Phe-d-Trp-Lys-Thr-Cys)-Thr(ol), DTPA = diethylene-triamine-penta-acetic acid), consistent with the higher receptor affinity of the first compound. Our observations of