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441 results on '"Hansen, Paul Robert"'

102. Cytotoxicity and in vivo efficacy of a novel antimicrobial peptoid against Staphylococcus pseudintermedius

Author

Damborg, Peter Panduro, Skindersø, Mette E, Hansen, Paul Robert, Bahnsen, Jesper Søborg, Nielsen, Hanne Mørck, Guardabassi, Luca, Damborg, Peter Panduro, Skindersø, Mette E, Hansen, Paul Robert, Bahnsen, Jesper Søborg, Nielsen, Hanne Mørck, and Guardabassi, Luca

Abstract

Objectives: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is emerging in dogs worldwide, and few or no treatment options are available for dogs infected by this pathogen due to its multi-resistance phenotype. The objective of this study was to evaluate cytotoxicity and investigate the in vivo efficacy of a novel peptoid (D2) previously shown to be effective against S. pseudintermedius in vitro. Methods: D2 was subjected to an array of cytotoxicity assays targeting proliferation, cellular stress, apoptosis and cell cycle in Jurkat cells. D2 was then formulated into a gel at a concentration corresponding to 10 X the highest MIC detected in S. pseudintermedius. The peptoid gel was tested using a murine skin infection model: DBA/2 mice were inoculated with an MRSP strain on a 3X2 cm scraped skin surface (day 0) followed by topical treatment twice daily with either D2 gel, placebo gel or fusidic acid ointment (day 1-3). Mice were euthanized on day 4. Affected skin was homogenized and CFU/ml was quantified by plate dilution on selective media. Results: D2 did not mediate apoptosis and showed limited effect on Jurkat cell viability and cell cycle at a concentration similar to that used in the murine model. Three days of D2 treatment did not have any significant effect on S. pseudintermedius counts in mice skin compared to placebo treatment. On the contrary, fusidic acid reduced bacterial counts significantly compared to D2 and placebo. Conclusion: S. pseudintermedius was used for the first time in this murine skin infection model and appeared to colonize well. The lacking effect of D2 in vivo could be due to either a too low concentration or an inhibitory effect of the gel formulation used. The next step will be to find the optimal concentration working in mice and assess toxicity for the chosen concentration.

Published
2012

107. Evaluation of 4-[(18)F]fluorobenzoyl-FALGEA-NH(2) as a positron emission tomography tracer for epidermal growth factor receptor mutation variant III imaging in cancer

Author

Denholt, Charlotte Lund, Binderup, Tina, Stockhausen, Marie-Thérése, Poulsen, Hans Skovgaard, Spang-Thomsen, Mogens, Hansen, Paul Robert, Gillings, Nic, Kjær, Andreas, Denholt, Charlotte Lund, Binderup, Tina, Stockhausen, Marie-Thérése, Poulsen, Hans Skovgaard, Spang-Thomsen, Mogens, Hansen, Paul Robert, Gillings, Nic, and Kjær, Andreas

Abstract

This study describes the radiosynthesis, in vitro and in vivo evaluation of the novel small peptide radioligand, 4-[(18)F]fluorobenzoyl-Phe-Ala-Leu-Gly-Glu-Ala-NH(2,) ([(18)F]FBA-FALGEA-NH(2)) as a positron emission tomography (PET) tracer for imaging of the cancer specific epidermal growth factor receptor (EGFR) variant III mutation, EGFRvIII.

Published
2011

111. The interaction between calreticulin and immunoglobulin G and immunoglobulin Y

Author

Møllegaard, Karen Mai, Duus, Karen, Træholt, Sofie Dietz, Thaysen-Andersen, Morten, Liu, Yan, Palma, Angelina S., Feizi, Ten, Hansen, Paul Robert, Højrup, Peter, Houen, Gunnar, Møllegaard, Karen Mai, Duus, Karen, Træholt, Sofie Dietz, Thaysen-Andersen, Morten, Liu, Yan, Palma, Angelina S., Feizi, Ten, Hansen, Paul Robert, Højrup, Peter, and Houen, Gunnar

Published
2011

113. Epitope mapping of an autoantibody to the N-Methyl D-aspartate receptor in encephalitis

Author

Hansen, Paul Robert, Houen, Gunnar, Amrutkar, Surekha Dipak, Hansen, Paul Robert, Houen, Gunnar, and Amrutkar, Surekha Dipak

Abstract

N-Methyl D-aspartate (NMDA) receptors are a subclass of the excitatory, ionotropic L-glutamate neurotransmitter receptors. They are important for the function of learning, memory and in synaptogenesis during the development of central nervous system. Dysfunction of these receptors generates neurological and psychiatric disorders. Anti-NMDAR encephalitis is an autoimmune disease in which autoantibodies are produced against the NMDA receptor. These autoantibodies may be used as biomarker for such disorders. It has been found that autoantibody in the serum and cerebrospinal fluid (CSF) bind specifically to an epitope located on the extracellular N- terminal domain of the NR1 subunits (25-380). In this study I mapped the epitope of a monoclonal NMDAR1 antibody using resin-bound peptides covering the NR1 subunit and synthesised N-terminally truncated peptides on a TentaGel resin using 4-hydroxymehtyl benzoic acid (HMBA) linker. The linker is acid stable, remains on the resin and allows the side-chain protecting groups to be cleaved. The free peptides if required were obtained by treating with 1M NaOH. The resin-bound peptides were screened in order to find the minimal peptide length required for antibody recognition. The short linear immuno-dominant NPSDK epitope was identified by solid phase peptide synthesis and competitive inhibition assay. It was found to be located on the extracellular S2 segment situated next to the GT linker of the NR1 subunit. Our study reveals that all amino acid residues are essential for antibody binding and the C-terminal lysine (K) residue is important for monoclonal antibody recognition. The linear epitope NPSDK is useful for comparing the antigenicity of the protein receptor and to produce the antibodies against the NMDAR1 by immunization. It may provide useful information for researchers to develop a medicine for anti-NMDAR encephalitis.

Published
2011

121. Trypsin stability of lysine-peptoid hybrids

Author

Valle, Susan Del, Escher, Emanuel, Lubell, William D., Ryge, Trine S., Hansen, Paul Robert, Valle, Susan Del, Escher, Emanuel, Lubell, William D., Ryge, Trine S., and Hansen, Paul Robert

Published
2009

122. Fallaxin analogues with improved antibacterial activity

Author

Valle, Susan Del, Escher, Emanuel, Lubell, William D., Søndergaard, Sandra Lerche, Frimodt-Møller, N., Hansen, Paul Robert, Valle, Susan Del, Escher, Emanuel, Lubell, William D., Søndergaard, Sandra Lerche, Frimodt-Møller, N., and Hansen, Paul Robert

Published
2009

125. Identification of novel peptide ligands for the cancer-specific receptor mutation EFGRvIII using a mixture-based synthetic combinatorial library

Author

Denholt, Charlotte Lund, Hansen, Paul Robert, Pedersen, Nina, Poulsen, Hans Skovgaard, Gillings, Nic, Kjær, Andreas, Kjaer, Andreas, Denholt, Charlotte Lund, Hansen, Paul Robert, Pedersen, Nina, Poulsen, Hans Skovgaard, Gillings, Nic, Kjær, Andreas, and Kjaer, Andreas

Abstract

We report here, the design and synthesis of a positional scanning synthetic combinatorial library for the identification of novel peptide ligands targeted against the cancer-specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in several kinds of cancer, in particular, ovarian, glioblastomas, and breast cancer, but not in normal tissue. The library consisted of six individual positional sublibraries in the format, H-O(1-6)XXXXX-NH(2), O being one of the 19 proteinogenic amino acids (cysteine omitted) and X an equimolar mixture of these. The library consisted of 114 mixtures in total. Using a biotin-streptavidin assay, the binding of each sublibrary to NR6M, NR6W-A, and NR6 cells was tested. These cells express EGFRvIII, EGFR, and neither of the receptors, respectively. The result from each sublibrary was examined to identify the most active amino acid residue at each position. On the basis of this knowledge, eight peptides were synthesized and tested for binding to EGFRvIII. We identified one peptide, H-FALGEA-NH(2), that showed more selective binding to the mutated receptor than the EGFRvIII specific peptide PEPHC1. This study demonstrates the value of using mixture-based combinatorial positional scanning libraries for the identification of novel peptide ligands targeted against the cancer-specific EGFRvIII. Our best candidate H-FALGEA-NH(2) will be radioactively labeled and evaluated as an imaging agent for positron emission tomography investigation for diagnosis, staging, and monitoring of therapy of various types of cancer.

Published
2009

134. The chaperone and potential mannan-binding lectin (MBL) co-receptor calreticulin interacts with MBL through the binding site for MBL-associated serine proteases

Author

Pagh, Rasmus, Duus, Karen, Laursen, Inga, Hansen, Paul Robert, Mangor, Julie, Thielens, Nicole, Arlaud, Gérard J., Kongerslev, Leif, Højrup, Peter, Houen, Gunnar, Pagh, Rasmus, Duus, Karen, Laursen, Inga, Hansen, Paul Robert, Mangor, Julie, Thielens, Nicole, Arlaud, Gérard J., Kongerslev, Leif, Højrup, Peter, and Houen, Gunnar

Published
2008

141. Development of 18F-labelled EGFRvIII targeting peptides

Author

Hansen, C.L., Kuhnast, B., Pedersen, N., Hinnen, F., Poulsen, H.S., Gillings, N., Hansen, Paul Robert, Kjær, A., Dolle, F., Hansen, C.L., Kuhnast, B., Pedersen, N., Hinnen, F., Poulsen, H.S., Gillings, N., Hansen, Paul Robert, Kjær, A., and Dolle, F.

Published
2007

143. Structure-activity study of the antibacterial peptide fallaxin

Author

Søndergaard, Sandra Lerche, Frimodt-Møller, Niels, Kragelund, Birthe Brandt, Hansen, Paul Robert, Søndergaard, Sandra Lerche, Frimodt-Møller, Niels, Kragelund, Birthe Brandt, and Hansen, Paul Robert

Abstract

Fallaxin is a 25-mer antibacterial peptide amide, which was recently isolated from the West Indian mountain chicken frog Leptodactylus fallax. Fallaxin has been shown to inhibit the growth of several Gram-negative bacteria including Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Here, we report a structure-activity study of fallaxin based on 65 analogs, including a complete alanine scan and a full set of N- and C-terminal truncated analogs. The fallaxin analogs were tested for hemolytic activity and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate resistant S. aureus, (VISA), methicillin-susceptible S. aureus (MSSA), E. coli, K. pneumoniae, and P. aeruginosa. We identified several analogs, which showed improved antibacterial activity compared to fallaxin. Our best candidate was FA12, which displayed MIC values of 3.12, 25, 25, and 50 µM against E. coli, K. pneumoniae, MSSA, and VISA, respectively. Furthermore, we correlated the antibacterial activity with various structural parameters such as charge, hydrophobicity "<"H"" style="width: 4px; height: 15px; border-width: 0px"/>, mean hydrophobic moment "<"µH"" style="width: 4px; height: 15px; border-width: 0px"/>, and

Published
2007

144. Peptide binding specificity of the chaperone calreticulin

Author

Sandhu, Noreen, Duus, Karen, Jørgensen, Charlotte S., Hansen, Paul Robert, Bruun, Susanne W., Pedersen, Lars Ø., Højrup, Peter, Houen, Gunnar, Sandhu, Noreen, Duus, Karen, Jørgensen, Charlotte S., Hansen, Paul Robert, Bruun, Susanne W., Pedersen, Lars Ø., Højrup, Peter, and Houen, Gunnar

Published
2007

148. Single amino acid substitution analogues of the antibacterial peptide [A7]-anoplin

Author

Rolka, Krzysztof, Rekowski, Piotr, Silberring, Jerzy, Hansen, Paul Robert, Ifrah, Dan, Lianee, Henriette T., Thing, Christen Salomon, Vitved, Tine, Rolka, Krzysztof, Rekowski, Piotr, Silberring, Jerzy, Hansen, Paul Robert, Ifrah, Dan, Lianee, Henriette T., Thing, Christen Salomon, and Vitved, Tine

Published
2006

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